WorldWideScience

Sample records for peripheral runner speed

  1. Study of speed endurance middle distance runners

    Directory of Open Access Journals (Sweden)

    R.V. Golovaschenko

    2013-12-01

    Full Text Available Purpose : To investigate the boost performance speed endurance runners who specialize in middle-distance running . Material and methods : The study involved team members Vinnytsia region in an amount of 44 people, whose average age was 20,2 ± 2,1 years. Classes are held during the 21-day mesocycle, 5 times a week, twice a day. Things were aimed at enhancing the development of indicators of special speed endurance. Results : The dynamics of the running speed of the model segments that characterize speed endurance athletes. Proved that the improved running 400 meter intervals helps reduce travel time competitive distance of 1500 meters. Conclusion : The use of the program contributes to higher speed endurance, which determines the result in the women's 1,500 meters.

  2. Relationship between foot strike pattern, running speed, and footwear condition in recreational distance runners.

    Science.gov (United States)

    Cheung, Roy T H; Wong, Rodney Y L; Chung, Tim K W; Choi, R T; Leung, Wendy W Y; Shek, Diana H Y

    2017-06-01

    Compared to competitive runners, recreational runners appear to be more prone to injuries, which have been associated with foot strike patterns. Surprisingly, only few studies had examined the foot strike patterns outside laboratories. Therefore, this study compared the foot strike patterns in recreational runners at outdoor tracks with previously reported data. We also investigated the relationship between foot strike pattern, speed, and footwear in this cohort. Among 434 recreational runners analysed, 89.6% of them landed with rearfoot strike (RFS). Only 6.9 and 3.5% landed with midfoot and forefoot, respectively. A significant shift towards non-RFS was observed in our cohort, when compared with previously reported data. When speed increased by 1 m/s, the odds of having forefoot strike and midfoot strike relative to RFS increased by 2.3 times and 2.6 times, respectively. Runners were 9.2 times more likely to run with a forefoot strike in minimalists compared to regular running shoes, although 70% of runners in minimalists continued to use a RFS. These findings suggest that foot strike pattern may differ across running conditions and runners should consider these factors in order to mitigate potential injury.

  3. Clinical Impact of Speed Variability to Identify Ultramarathon Runners at Risk for Acute Kidney Injury.

    Directory of Open Access Journals (Sweden)

    Sen-Kuang Hou

    Full Text Available Ultramarathon is a high endurance exercise associated with a wide range of exercise-related problems, such as acute kidney injury (AKI. Early recognition of individuals at risk of AKI during ultramarathon event is critical for implementing preventative strategies.To investigate the impact of speed variability to identify the exercise-related acute kidney injury anticipatively in ultramarathon event.This is a prospective, observational study using data from a 100 km ultramarathon in Taipei, Taiwan. The distance of entire ultramarathon race was divided into 10 splits. The mean and variability of speed, which was determined by the coefficient of variation (CV in each 10 km-split (25 laps of 400 m oval track were calculated for enrolled runners. Baseline characteristics and biochemical data were collected completely 1 week before, immediately post-race, and one day after race. The main outcome was the development of AKI, defined as Stage II or III according to the Acute Kidney Injury Network (AKIN criteria. Multivariate analysis was performed to determine the independent association between variables and AKI development.26 ultramarathon runners were analyzed in the study. The overall incidence of AKI (in all Stages was 84.6% (22 in 26 runners. Among these 22 runners, 18 runners were determined as Stage I, 4 runners (15.4% were determined as Stage II, and none was in Stage III. The covariates of BMI (25.22 ± 2.02 vs. 22.55 ± 1.96, p = 0.02, uric acid (6.88 ± 1.47 vs. 5.62 ± 0.86, p = 0.024, and CV of speed in specific 10-km splits (from secondary 10 km-split (10th - 20th km-split to 60th - 70th km-split were significantly different between runners with or without AKI (Stage II in univariate analysis and showed discrimination ability in ROC curve. In the following multivariate analysis, only CV of speed in 40th - 50th km-split continued to show a significant association to the development of AKI (Stage II (p = 0.032.The development of exercise

  4. Effect of increased and maintained frequency of speed endurance training on performance and muscle adaptations in runners

    DEFF Research Database (Denmark)

    Skovgaard, Casper; Almquist, Nicki Winfield; Bangsbo, Jens

    2017-01-01

    The aim of the study was, in runners accustomed to speed endurance training (SET), to examine the effect of increased and maintained frequency of SET on performance and muscular adaptations. After familiarization (FAM) to SET, eighteen male (n=14) and female (n=4) runners (VO2-max: 57.3±3.4 ml·mi...

  5. Ankle and knee kinetics between strike patterns at common training speeds in competitive male runners.

    Science.gov (United States)

    Kuhman, Daniel; Melcher, Daniel; Paquette, Max R

    2016-01-01

    The purpose of this study was to investigate the interaction of foot strike and common speeds on sagittal plane ankle and knee joint kinetics in competitive rear foot strike (RFS) runners when running with a RFS pattern and an imposed forefoot strike (FFS) pattern. Sixteen competitive habitual male RFS runners ran at two different speeds (i.e. 8 and 6 min mile(-1)) using their habitual RFS and an imposed FFS pattern. A repeated measures analysis of variance was used to assess a potential interaction between strike pattern and speed for selected ground reaction force (GRF) variables and, sagittal plane ankle and knee kinematic and kinetic variables. No foot strike and speed interaction was observed for any of the kinetic variables. Habitual RFS yielded a greater loading rate of the vertical GRF, peak ankle dorsiflexor moment, peak knee extensor moment, peak knee eccentric extensor power, peak dorsiflexion and sagittal plane knee range of motion compared to imposed FFS. Imposed FFS yielded greater maximum vertical GRF, peak ankle plantarflexor moment, peak ankle eccentric plantarflexor power and sagittal plane ankle ROM compared to habitual RFS. Consistent with previous literature, imposed FFS in habitual RFS reduces eccentric knee extensor and ankle dorsiflexor involvement but produce greater eccentric ankle plantarflexor action compared to RFS. These acute differences between strike patterns were independent of running speeds equivalent to typical easy and hard training runs in competitive male runners. Current findings along with previous literature suggest differences in lower extremity kinetics between habitual RFS and imposed FFS running are consistent among a variety of runner populations.

  6. Effect of speed endurance and strength training on performance, running economy and muscular adaptations in endurance-trained runners

    DEFF Research Database (Denmark)

    Vorup Petersen, Jacob; Tybirk, Jonas; Gunnarsson, Thomas Petursson

    2016-01-01

    PURPOSE: To investigate the effects of combined strength and speed endurance (SE) training along with a reduced training volume on performance, running economy and muscular adaptations in endurance-trained runners. METHODS: Sixteen male endurance runners (VO2-max: ~60 ml kg(-1) min(-1)) were rand...... and speed endurance training, along with a reduced training volume, can improve short-term exercise capacity and induce muscular adaptations related to anaerobic capacity in endurance-trained runners.......PURPOSE: To investigate the effects of combined strength and speed endurance (SE) training along with a reduced training volume on performance, running economy and muscular adaptations in endurance-trained runners. METHODS: Sixteen male endurance runners (VO2-max: ~60 ml kg(-1) min(-1)) were...... randomly assigned to either a combined strength and SE training (CSS; n = 9) or a control (CON; n = 7) group. For 8 weeks, CSS replaced their normal moderate-intensity training (~63 km week(-1)) with SE (2 × week(-1)) and strength training (2 × week(-1)) as well as aerobic high (1 × week(-1)) and moderate...

  7. Changes in blood morphology and chosen biochemical parameters in ultra-marathon runners during a 100-km run in relation to the age and speed of runners

    Directory of Open Access Journals (Sweden)

    Zbigniew Jastrzębski

    2016-10-01

    Full Text Available Objectives: The objective of the study was to reveal morphology, electrolyte and chosen biochemical parameters in terms of health risk in runners in reference to their age and running speed in the case of running a distance of 100 km, which occur after 12 h or 24 h of recovery. Material and Methods: Fourteen experienced, male, amateur, ultra-marathon runners, divided into two age and two speed groups took part in the 100-km run. Blood samples for analyses indexes were collected from the ulnar vein just before the run, after 25 km, 50 km, 75 km and 100 km, as well as 12 h and 24 h after termination of the run. Results: The sustained ultramarathon run along with the distance covered (p < 0.05 caused an increase in myoglobin (max 90-fold, bilirubin (max 2.8-fold and total antioxidant status (max 1.15-fold, which also continued during the recovery. Significant changes in the number of white blood cells were observed with each sequential course and could be associated with muscle damage. The electrolyte showed changes towards slight hyperkalemia, but no changes in natrium and calcium concentrations. There were no significant differences between the age and speed groups for all the parameters after completing the 100-km run as well as after 12 h and 24 h of recovery. Conclusions: Considering changes in blood morphology and chosen biochemical parameters in ultra-marathon runners during a 100-km run it can be stated that such an exhausting effort may be dangerous for human health due to metabolic changes and large damage to the organs. Negative metabolic changes are independent of age of an ultramarathon runner and occur both in younger (32±5.33 years and older participants (50.56±9.7 years. It can be concluded that organ damage and negative metabolic changes during a 100-km run occur similarly in participants less experienced as well as in well trained runners. Int J Occup Med Environ Health 2016;29(5:801–814

  8. Effect of speed endurance training and reduced training volume on running economy and single muscle fiber adaptations in trained runners

    DEFF Research Database (Denmark)

    Skovgaard, Casper; Christiansen, Danny; Christensen, Peter Møller

    2018-01-01

    The aim of the present study was to examine whether improved running economy with a period of speed endurance training and reduced training volume could be related to adaptations in specific muscle fibers. Twenty trained male (n = 14) and female (n = 6) runners (maximum oxygen consumption (VO2 -m.......3 ± 0.3 vs. 18.9 ± 0.3 km/h) after than before the intervention. Thus, improved running economy with intense training may be related to changes in expression of proteins linked to energy consuming processes in primarily ST muscle fibers....

  9. Control entropy identifies differential changes in complexity of walking and running gait patterns with increasing speed in highly trained runners.

    Science.gov (United States)

    McGregor, Stephen J; Busa, Michael A; Skufca, Joseph; Yaggie, James A; Bollt, Erik M

    2009-06-01

    Regularity statistics have been previously applied to walking gait measures in the hope of gaining insight into the complexity of gait under different conditions and in different populations. Traditional regularity statistics are subject to the requirement of stationarity, a limitation for examining changes in complexity under dynamic conditions such as exhaustive exercise. Using a novel measure, control entropy (CE), applied to triaxial continuous accelerometry, we report changes in complexity of walking and running during increasing speeds up to exhaustion in highly trained runners. We further apply Karhunen-Loeve analysis in a new and novel way to the patterns of CE responses in each of the three axes to identify dominant modes of CE responses in the vertical, mediolateral, and anterior/posterior planes. The differential CE responses observed between the different axes in this select population provide insight into the constraints of walking and running in those who may have optimized locomotion. Future comparisons between athletes, healthy untrained, and clinical populations using this approach may help elucidate differences between optimized and diseased locomotor control.

  10. Effect of speed endurance training and reduced training volume on running economy and single muscle fiber adaptations in trained runners.

    Science.gov (United States)

    Skovgaard, Casper; Christiansen, Danny; Christensen, Peter M; Almquist, Nicki W; Thomassen, Martin; Bangsbo, Jens

    2018-02-01

    The aim of the present study was to examine whether improved running economy with a period of speed endurance training and reduced training volume could be related to adaptations in specific muscle fibers. Twenty trained male (n = 14) and female (n = 6) runners (maximum oxygen consumption (VO 2 -max): 56.4 ± 4.6 mL/min/kg) completed a 40-day intervention with 10 sessions of speed endurance training (5-10 × 30-sec maximal running) and a reduced (36%) volume of training. Before and after the intervention, a muscle biopsy was obtained at rest, and an incremental running test to exhaustion was performed. In addition, running at 60% vVO 2 -max, and a 10-km run was performed in a normal and a muscle slow twitch (ST) glycogen-depleted condition. After compared to before the intervention, expression of mitochondrial uncoupling protein 3 (UCP3) was lower (P economy at 60% vVO 2 -max (11.6 ± 0.2 km/h) and at v10-km (13.7 ± 0.3 km/h) was ~2% better (P economy with intense training may be related to changes in expression of proteins linked to energy consuming processes in primarily ST muscle fibers. © 2018 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

  11. Training improves reading speed in peripheral vision: Is it due to attention?

    OpenAIRE

    Lee, Hye-Won; Kwon, MiYoung; Legge, Gordon E.; Gefroh, Joshua J.

    2010-01-01

    Previous research has shown that perceptual training in peripheral vision, using a letter-recognition task, increases reading speed and letter recognition (Chung, Legge, & Cheung, 2004). We tested the hypothesis that enhanced deployment of spatial attention to peripheral vision explains this training effect. Subjects were pre- and post-tested with 3 tasks at 10° above and below fixation—RSVP reading speed, trigram letter recognition (used to construct visual-span profiles), and deployment of ...

  12. Runner's Knee

    Science.gov (United States)

    ... require a lot of knee bending, such as biking, jumping, or skiing. Runner's knee happens when the ... is out of alignment, activities like running or biking can wear down the cartilage of the kneecap ( ...

  13. Training improves reading speed in peripheral vision: is it due to attention?

    Science.gov (United States)

    Lee, Hye-Won; Kwon, Miyoung; Legge, Gordon E; Gefroh, Joshua J

    2010-06-01

    Previous research has shown that perceptual training in peripheral vision, using a letter-recognition task, increases reading speed and letter recognition (S. T. L. Chung, G. E. Legge, & S. H. Cheung, 2004). We tested the hypothesis that enhanced deployment of spatial attention to peripheral vision explains this training effect. Subjects were pre- and post-tested with 3 tasks at 10° above and below fixation-RSVP reading speed, trigram letter recognition (used to construct visual-span profiles), and deployment of spatial attention (measured as the benefit of a pre-cue for target position in a lexical-decision task). Groups of five normally sighted young adults received 4 days of trigram letter-recognition training in upper or lower visual fields, or central vision. A control group received no training. Our measure of deployment of spatial attention revealed visual-field anisotropies; better deployment of attention in the lower field than the upper, and in the lower-right quadrant compared with the other three quadrants. All subject groups exhibited slight improvement in deployment of spatial attention to peripheral vision in the post-test, but this improvement was not correlated with training-related increases in reading speed and the size of visual-span profiles. Our results indicate that improved deployment of spatial attention to peripheral vision does not account for improved reading speed and letter recognition in peripheral vision.

  14. Damage to Liver and Skeletal Muscles in Marathon Runners During a 100 km Run With Regard to Age and Running Speed

    Directory of Open Access Journals (Sweden)

    Jastrzębski Zbigniew

    2015-03-01

    Full Text Available The purpose of this study was to determine: (1 whether damage to liver and skeletal muscles occurs during a 100 km run; (2 whether the metabolic response to extreme exertion is related to the age or running speed of the participant; (3 whether it is possible to determine the optimal running speed and distance for long-distance runners’ health by examining biochemical parameters in venous blood. Fourteen experienced male amateur ultra-marathon runners, divided into two age groups, took part in a 100 km run. Blood samples for liver and skeletal muscle damage indexes were collected from the ulnar vein just before the run, after 25, 50, 75 and 100 km, and 24 hours after termination of the run. A considerable increase in alanine aminotransferase (ALT and aspartate aminotransferase (AST was observed with the distance covered (p < 0.05, which continued during recovery. An increase in the mean values of lactate dehydrogenase (LDH, creatine kinase (CK and C-reactive protein (CRP (p < 0.05 was observed with each sequential course. The biggest differences between the age groups were found for the activity of liver enzymes and LDH after completing 75 km as well as after 24 hours of recovery. It can be concluded that the response to extreme exertion deteriorates with age in terms of the active movement apparatus.

  15. Tapering strategies in elite British endurance runners.

    Science.gov (United States)

    Spilsbury, Kate L; Fudge, Barry W; Ingham, Stephen A; Faulkner, Steve H; Nimmo, Myra A

    2015-01-01

    The aim of the study was to explore pre-competition training practices of elite endurance runners. Training details from elite British middle distance (MD; 800 m and 1500 m), long distance (LD; 3000 m steeplechase to 10,000 m) and marathon (MAR) runners were collected by survey for 7 days in a regular training (RT) phase and throughout a pre-competition taper. Taper duration was [median (interquartile range)] 6 (3) days in MD, 6 (1) days in LD and 14 (8) days in MAR runners. Continuous running volume was reduced to 70 (16)%, 71 (24)% and 53 (12)% of regular levels in MD, LD and MAR runners, respectively (P training (MD; 53 (45)%, LD; 67 (23)%, MAR; 64 (34)%, P training intensity was above race speed in LD and MAR runners (112 (27)% and 114 (3)%, respectively, P training undertaken prior to the taper in elite endurance runners is predictive of the tapering strategy implemented before competition.

  16. Discrimination of gender-, speed-, and shoe-dependent movement patterns in runners using full-body kinematics.

    Science.gov (United States)

    Maurer, Christian; Federolf, Peter; von Tscharner, Vinzenz; Stirling, Lisa; Nigg, Benno M

    2012-05-01

    Changes in gait kinematics have often been analyzed using pattern recognition methods such as principal component analysis (PCA). It is usually just the first few principal components that are analyzed, because they describe the main variability within a dataset and thus represent the main movement patterns. However, while subtle changes in gait pattern (for instance, due to different footwear) may not change main movement patterns, they may affect movements represented by higher principal components. This study was designed to test two hypotheses: (1) speed and gender differences can be observed in the first principal components, and (2) small interventions such as changing footwear change the gait characteristics of higher principal components. Kinematic changes due to different running conditions (speed - 3.1m/s and 4.9 m/s, gender, and footwear - control shoe and adidas MicroBounce shoe) were investigated by applying PCA and support vector machine (SVM) to a full-body reflective marker setup. Differences in speed changed the basic movement pattern, as was reflected by a change in the time-dependent coefficient derived from the first principal. Gender was differentiated by using the time-dependent coefficient derived from intermediate principal components. (Intermediate principal components are characterized by limb rotations of the thigh and shank.) Different shoe conditions were identified in higher principal components. This study showed that different interventions can be analyzed using a full-body kinematic approach. Within the well-defined vector space spanned by the data of all subjects, higher principal components should also be considered because these components show the differences that result from small interventions such as footwear changes. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

  17. Effects of Continuous and Interval Training on Running Economy, Maximal Aerobic Speed and Gait Kinematics in Recreational Runners.

    Science.gov (United States)

    González-Mohíno, Fernando; González-Ravé, José M; Juárez, Daniel; Fernández, Francisco A; Barragán Castellanos, Rubén; Newton, Robert U

    2016-04-01

    The purpose of this study was to evaluate the effects on running economy (RE), V[Combining Dot Above]O2max, maximal aerobic speed (MAS), and gait kinematics (step length [SL] and frequency, flight and contact time [CT]) in recreational athletes, with 2 different training methods, Interval and Continuous (CON). Eleven participants were randomly distributed in an interval training group (INT; n = 6) or CON training group (CON; n = 5). Interval training and CON performed 2 different training programs (95-110% and 70-75% of MAS, respectively), which consisted of 3 sessions per week during 6 weeks with the same external workload (%MAS × duration). An incremental test to exhaustion was performed to obtain V[Combining Dot Above]O2max, MAS, RE, and gait variables (high speed camera) before and after the training intervention. There was a significant improvement (p ≤ 0.05) in RE at 60 and 90% of MAS by the CON group; without changes in gait. The INT group significantly increased MAS and higher stride length at 80, 90, and 100% of MAS and lower CT at 100% of MAS. As expected, training adaptations are highly specific to the overload applied with CON producing improvements in RE at lower percentage of MAS whereas INT produces improvements in MAS. The significantly increased stride length and decreased CT for the INT group are an important outcome of favorable changes in running gait.

  18. Trabecular bone in the calcaneus of runners.

    Science.gov (United States)

    Best, Andrew; Holt, Brigitte; Troy, Karen; Hamill, Joseph

    2017-01-01

    Trabecular bone of the human calcaneus is subjected to extreme repetitive forces during endurance running and should adapt in response to this strain. To assess possible bone functional adaptation in the posterior region of the calcaneus, we recruited forefoot-striking runners (n = 6), rearfoot-striking runners (n = 6), and non-runners (n = 6), all males aged 20-41 for this institutionally approved study. Foot strike pattern was confirmed for each runner using a motion capture system. We obtained high resolution peripheral computed tomography scans of the posterior calcaneus for both runners and non-runners. No statistically significant differences were found between runners and nonrunners or forefoot strikers and rearfoot strikers. Mean trabecular thickness and mineral density were greatest in forefoot runners with strong effect sizes (forefoot strikers, likely an artifact of greater running volume and earlier onset of running in this subgroup; thus, individuals with the greatest summative loading stimulus had, after body mass adjustment, the thickest trabeculae. Further study with larger sample sizes is necessary to elucidate the role of footstrike on calcaneal trabecular structure. To our knowledge, intraspecific body mass correlations with measures of trabecular robusticity have not been reported elsewhere. We hypothesize that early adoption of running and years of sustained moderate volume running stimulate bone modeling in trabeculae of the posterior calcaneus.

  19. The Effect of Training at 2100-m Altitude on Running Speed and Session Rating of Perceived Exertion at Different Intensities in Elite Middle-Distance Runners.

    Science.gov (United States)

    Sharma, Avish P; Saunders, Philo U; Garvican-Lewis, Laura A; Clark, Brad; Stanley, Jamie; Robertson, Eileen Y; Thompson, Kevin G

    2017-04-01

    To determine the effect of training at 2100-m natural altitude on running speed (RS) during training sessions over a range of intensities relevant to middle-distance running performance. In an observational study, 19 elite middle-distance runners (mean ± SD age 25 ± 5 y, VO 2 max, 71 ± 5 mL · kg -1 · min -1 ) completed either 4-6 wk of sea-level training (CON, n = 7) or a 4- to 5-wk natural altitude-training camp living at 2100 m and training at 1400-2700 m (ALT, n = 12) after a period of sea-level training. Each training session was recorded on a GPS watch, and athletes also provided a score for session rating of perceived exertion (sRPE). Training sessions were grouped according to duration and intensity. RS (km/h) and sRPE from matched training sessions completed at sea level and 2100 m were compared within ALT, with sessions completed at sea level in CON describing normal variation. In ALT, RS was reduced at altitude compared with sea level, with the greatest decrements observed during threshold- and VO 2 max-intensity sessions (5.8% and 3.6%, respectively). Velocity of low-intensity and race-pace sessions completed at a lower altitude (1400 m) and/or with additional recovery was maintained in ALT, though at a significantly greater sRPE (P = .04 and .05, respectively). There was no change in velocity or sRPE at any intensity in CON. RS in elite middle-distance athletes is adversely affected at 2100-m natural altitude, with levels of impairment dependent on the intensity of training. Maintenance of RS at certain intensities while training at altitude can result in a higher perceived exertion.

  20. High-speed BWR power plant simulations on the special-purpose peripheral processor AD10

    International Nuclear Information System (INIS)

    Wulff, W.; Cheng, H.S.; Lekach, S.V.; Mallen, A.N.

    1985-01-01

    A newly developed technique is described for fast, on-line simulations of normal and accidental transients in nuclear power plants. The technique is based on the utilization of the special-purpose peripheral processor AD10, which is specifically designed for high-speed systems simulations through integration of large systems of nonlinear ordinary differential equations. The Peach Bottom-II Boiling Water Reactor power plant has been simulated and results are presented. It is shown that the new technique not only advances safety analyses but also supports plant monitoring, failure diagnosis and accident mitigation, as well as the training of nuclear power plant operators. (author)

  1. Evaluating the role of low-speed centrifugation towards transfecting human peripheral blood mononuclear cell culture.

    Science.gov (United States)

    Majumdar, M; Ratho, R; Chawla, Y; Singh, M P

    2014-01-01

    The conventional method of transfection of suspension cells by chemical has proven to be very difficult. We present a new transfection protocol, wherein, low-speed centrifugation of cell culture plates immediately after adding the lipid: DNA complex significantly enhances the transfection efficiency. Peripheral blood mononuclear cells (PBMCs) were transfected with BLOCK-iT™ Fluorescent Oligo (scrambled siRNA) and lipofectamine complex using conventional and low-speed centrifugation modified transfection protocols. The efficiency of transfection was determined using flowcytometer and cell viability was checked using MTT assay. Incorporation of low-speed centrifugation significantly enhances the transfection efficiency of BLOCK-iT™ in the suspension culture of PBMCs as compared to conventional transfection method (99.8% vs 28.3%; P Centrifugation enhanced transfection (CET) technique is simple, time-saving and novel application without compromising the cell viability in the context of recently popular RNA interference in suspension cultures of PBMCs. This undemanding modification might be applicable to a wide variety of cell lines and solve crucial problem of researchers working with RNA interference in suspension cultures.

  2. Evaluating the role of low-speed centrifugation towards transfecting human peripheral blood mononuclear cell culture

    Directory of Open Access Journals (Sweden)

    M Majumdar

    2014-01-01

    Full Text Available The conventional method of transfection of suspension cells by chemical has proven to be very difficult. We present a new transfection protocol, wherein, low-speed centrifugation of cell culture plates immediately after adding the lipid: DNA complex significantly enhances the transfection efficiency. Peripheral blood mononuclear cells (PBMCs were transfected with BLOCK-iT™ Fluorescent Oligo (scrambled siRNA and lipofectamine complex using conventional and low-speed centrifugation modified transfection protocols. The efficiency of transfection was determined using flowcytometer and cell viability was checked using MTT assay. Incorporation of low-speed centrifugation significantly enhances the transfection efficiency of BLOCK-iT™ in the suspension culture of PBMCs as compared to conventional transfection method (99.8% vs 28.3%; P < 0.0001, even at a low concentration of 40 picomoles without affecting the cell viability. Centrifugation enhanced transfection (CET technique is simple, time-saving and novel application without compromising the cell viability in the context of recently popular RNA interference in suspension cultures of PBMCs. This undemanding modification might be applicable to a wide variety of cell lines and solve crucial problem of researchers working with RNA interference in suspension cultures.

  3. Trabecular bone in the calcaneus of runners.

    Directory of Open Access Journals (Sweden)

    Andrew Best

    Full Text Available Trabecular bone of the human calcaneus is subjected to extreme repetitive forces during endurance running and should adapt in response to this strain. To assess possible bone functional adaptation in the posterior region of the calcaneus, we recruited forefoot-striking runners (n = 6, rearfoot-striking runners (n = 6, and non-runners (n = 6, all males aged 20-41 for this institutionally approved study. Foot strike pattern was confirmed for each runner using a motion capture system. We obtained high resolution peripheral computed tomography scans of the posterior calcaneus for both runners and non-runners. No statistically significant differences were found between runners and nonrunners or forefoot strikers and rearfoot strikers. Mean trabecular thickness and mineral density were greatest in forefoot runners with strong effect sizes (<0.80. Trabecular thickness was positively correlated with weekly running distance (r2 = 0.417, p<0.05 and years running (r2 = 0.339, p<0.05 and negatively correlated with age at onset of running (r2 = 0.515, p<0.01 Trabecular thickness, mineral density and bone volume ratio of nonrunners were highly correlated with body mass (r2 = 0.824, p<0.05 and nonrunners were significantly heavier than runners (p<0.05. Adjusting for body mass revealed significantly thicker trabeculae in the posterior calcaneus of forefoot strikers, likely an artifact of greater running volume and earlier onset of running in this subgroup; thus, individuals with the greatest summative loading stimulus had, after body mass adjustment, the thickest trabeculae. Further study with larger sample sizes is necessary to elucidate the role of footstrike on calcaneal trabecular structure. To our knowledge, intraspecific body mass correlations with measures of trabecular robusticity have not been reported elsewhere. We hypothesize that early adoption of running and years of sustained moderate volume running stimulate bone modeling in trabeculae of the

  4. Studies on water turbine runner which fish can pass through: In case of single stage axial runner

    International Nuclear Information System (INIS)

    Shimizu, Yukimari; Maeda, Takao; Nagoshi, Osamu; Ieda, Kazuma; Shinma, Hisako; Hagimoto, Michiko

    1994-01-01

    The relationship between water turbine runner design and operation and the safe passage of fish through the turbine is studied. The kinds of fish used in the tests are a dace, a sweet fish and a small salmon. A single stage axial runner is used. The velocity and pressure distributions were measured inside the turbine casing and along the casing wall. Many pictures showing fish passing through the rotating runner were taken and analyzed. The swimming speed of the fish was examined from video recordings. Fish pass through the runner more rapidly when they can determine and choose the easier path. Injury and mortality of fish are affected by the runner speed and the location of impact of the runner on the fish body

  5. Comparison of foot strike patterns of barefoot and minimally shod runners in a recreational road race

    OpenAIRE

    Peter Larson

    2014-01-01

    Background: Previous studies of foot strike patterns of distance runners in road races have typically found that the overwhelming majority of shod runners initially contact the ground on the rearfoot. However, none of these studies has attempted to quantify foot strike patterns of barefoot or minimally shod runners. This study classifies foot strike patterns of barefoot and minimally shod runners in a recreational road race. Methods: High-speed video footage was obtained of 169 barefoot an...

  6. The impact of self-reported psychological stress levels on changes to peripheral blood immune biomarkers in recreational marathon runners during training and recovery.

    Science.gov (United States)

    Rehm, Kristina E; Elci, Okan U; Hahn, Kathryn; Marshall, Gailen D

    2013-01-01

    Marathon training is both physically and psychologically stressful, both of which can lead to altered immunity. The purpose of this study was to determine if the overall immunoregulatory changes associated with the physical stress of marathon training are affected by psychological stress. Nineteen recreational marathoners completed the Perceived Stress Scale (PSS), State-Trait Anxiety Inventory (STAI) and Penn State Worry Questionnaire (PSWQ), and had levels of T cell subpopulations and cytokine (IFNγ, IL4 and IL10) production determined 4 weeks before (baseline), 24-48 h before (prerace) and 1 week after (recovery) participation in a marathon. PSS scores decreased at the prerace visit compared to baseline and remained low at recovery. Compared to baseline, there were significant changes to numerous immune measures at the prerace visit, including decreases in Th1/Th2 ratio, Tc1/Tc2 ratio, Tr1 and Th3 cell populations as well as decreases in IFNγ/IL4 cytokine ratio and IL10 production. Most immune parameters had returned to near baseline values at the recovery visit. Higher levels of perceived stress, anxiety and worry exacerbated many of the alterations in immunity that were observed at the prerace visit. Higher levels of perceived stress and worry had significant effects on changes to Treg, IL4 production and the IFNγ/IL4 cytokine ratio. Stress had an additional impact on changes in IL10 production. High anxiety levels resulted in significant changes to Treg, Tr1 and Th3. These data suggest that recreational marathon runners with higher levels of psychological stress may be more at risk for the immune alterations that are common during periods of prolonged physical training. Copyright © 2013 S. Karger AG, Basel.

  7. Extraction of impacted mandibular third molars - the effect of osteotomy at two speeds on peripheral bone: a histopathological analysis.

    Science.gov (United States)

    Siroraj, A Pearlcid; Giri G V V; Ramkumar, Subramaniam; Narasimhan, Malathi

    2016-05-01

    The aim of this study was to find out the ideal speed for making a precise osteotomy with minimal damage to the surrounding bone. Thirty-six patients were divided into two groups (n=18 in each) depending on the speed of the handpiece used for osteotomy (slow=20000rpm and fast=40000rpm). Samples were taken from the peripheral bone and examined histologically to measure the margins of the osteotomy, the amount of debris produced, and the degree of thermal osteonecrosis. The osteotomy made with the high speed handpiece was better than that made with the low speed one on all counts. The margins in the high speed group were more or less precisely as required, with less debris and no thermal necrosis, which illustrated the efficacy of a high speed osteotomy. These findings can apply to other procedures that involve osteotomies in maxillofacial surgery. Copyright © 2016 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  8. Predictor Variables for Marathon Race Time in Recreational Female Runners

    OpenAIRE

    Schmid, Wiebke; Knechtle, Beat; Knechtle, Patrizia; Barandun, Ursula; Rüst, Christoph Alexander; Rosemann, Thomas; Lepers, Romuald

    2012-01-01

    Purpose We intended to determine predictor variables of anthropometry and training for marathon race time in recreational female runners in order to predict marathon race time for future novice female runners. Methods Anthropometric characteristics such as body mass, body height, body mass index, circumferences of limbs, thicknesses of skin-folds and body fat as well as training variables such as volume and speed in running training were related to marathon race time using bi- and multi-varia...

  9. KINEMATIC CHANGES DURING A MARATHON FOR FAST AND SLOW RUNNERS

    Directory of Open Access Journals (Sweden)

    Maggie Chan-Roper

    2012-03-01

    Full Text Available The purpose of this study was to describe kinematic changes that occur during an actual marathon. We hypothesized that (1 certain running kinematic measures would change between kilometres 8 and 40 (miles 5 and 25 of a marathon and (2 fast runners would demonstrate smaller changes than slow runners. Subjects (n = 179 were selected according to finish time (Range = 2:20:47 to 5:30:10. Two high-speed cameras were used to measure sagittal-plane kinematics at kilometres 8 and 40 of the marathon. The dependent variables were stride length, contact time, peak knee flexion during support and swing, and peak hip flexion and extension during swing. Two-tailed paired t-tests were used to compare dependent variables between kilometres 8 and 40 for all subjects, and regression analyses were used to determine whether faster runners exhibited smaller changes (between miles 5 and 25 than slower runners. For all runners, every dependent variable changed significantly between kilometres 8 and 40 (p < 0.001. Stride length increased 1.3%, contact time increased 13.1%, peak knee flexion during support decreased 3.2%, and peak hip extension, knee flexion, and hip flexion during swing decreased 27.9%, increased 4.3%, and increased 7.4%, respectively (p < 0.001. Among these significant changes, all runners generally changed the same from kilometres 8 and 40 except that fast runners decreased peak knee flexion during support less than the slow runners (p < 0.002. We believe that these changes, for all runners (fast and slow, were due to fatigue. The fact that fast runners maintained knee flexion during support more consistently might be due to their condition on the race day. Strengthening of knee extensor muscles may facilitate increased knee flexion during support throughout a marathon

  10. Speed

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Speed. The rate of information transferred per second is the speed of the information. Measured in bits per second. Need for speed on the net: You-Tube phenomenon; IPTV; 3D Video telephony. Online gaming; HDTV.

  11. Metabolic factors limiting performance in marathon runners.

    Science.gov (United States)

    Rapoport, Benjamin I

    2010-10-21

    Each year in the past three decades has seen hundreds of thousands of runners register to run a major marathon. Of those who attempt to race over the marathon distance of 26 miles and 385 yards (42.195 kilometers), more than two-fifths experience severe and performance-limiting depletion of physiologic carbohydrate reserves (a phenomenon known as 'hitting the wall'), and thousands drop out before reaching the finish lines (approximately 1-2% of those who start). Analyses of endurance physiology have often either used coarse approximations to suggest that human glycogen reserves are insufficient to fuel a marathon (making 'hitting the wall' seem inevitable), or implied that maximal glycogen loading is required in order to complete a marathon without 'hitting the wall.' The present computational study demonstrates that the energetic constraints on endurance runners are more subtle, and depend on several physiologic variables including the muscle mass distribution, liver and muscle glycogen densities, and running speed (exercise intensity as a fraction of aerobic capacity) of individual runners, in personalized but nevertheless quantifiable and predictable ways. The analytic approach presented here is used to estimate the distance at which runners will exhaust their glycogen stores as a function of running intensity. In so doing it also provides a basis for guidelines ensuring the safety and optimizing the performance of endurance runners, both by setting personally appropriate paces and by prescribing midrace fueling requirements for avoiding 'the wall.' The present analysis also sheds physiologically principled light on important standards in marathon running that until now have remained empirically defined: The qualifying times for the Boston Marathon.

  12. Metabolic factors limiting performance in marathon runners.

    Directory of Open Access Journals (Sweden)

    Benjamin I Rapoport

    2010-10-01

    Full Text Available Each year in the past three decades has seen hundreds of thousands of runners register to run a major marathon. Of those who attempt to race over the marathon distance of 26 miles and 385 yards (42.195 kilometers, more than two-fifths experience severe and performance-limiting depletion of physiologic carbohydrate reserves (a phenomenon known as 'hitting the wall', and thousands drop out before reaching the finish lines (approximately 1-2% of those who start. Analyses of endurance physiology have often either used coarse approximations to suggest that human glycogen reserves are insufficient to fuel a marathon (making 'hitting the wall' seem inevitable, or implied that maximal glycogen loading is required in order to complete a marathon without 'hitting the wall.' The present computational study demonstrates that the energetic constraints on endurance runners are more subtle, and depend on several physiologic variables including the muscle mass distribution, liver and muscle glycogen densities, and running speed (exercise intensity as a fraction of aerobic capacity of individual runners, in personalized but nevertheless quantifiable and predictable ways. The analytic approach presented here is used to estimate the distance at which runners will exhaust their glycogen stores as a function of running intensity. In so doing it also provides a basis for guidelines ensuring the safety and optimizing the performance of endurance runners, both by setting personally appropriate paces and by prescribing midrace fueling requirements for avoiding 'the wall.' The present analysis also sheds physiologically principled light on important standards in marathon running that until now have remained empirically defined: The qualifying times for the Boston Marathon.

  13. CFD Simulation and Optimization of Very Low Head Axial Flow Turbine Runner

    Directory of Open Access Journals (Sweden)

    Yohannis Mitiku Tobo

    2015-10-01

    Full Text Available The main objective of this work is Computational Fluid Dynamics (CFD modelling, simulation and optimization of very low head axial flow turbine runner  to be used to drive  a centrifugal pump of turbine-driven pump. The ultimate goal of the optimization is to produce a power of 1kW at head less than 1m from flowing  river to drive centrifugal pump using mechanical coupling (speed multiplier gear directly. Flow rate, blade numbers, turbine rotational speed, inlet angle are parameters used in CFD modeling,  simulation and design optimization of the turbine runner. The computed results show that power developed by a turbine runner increases with increasing flow rate. Pressure inside the turbine runner increases with flow rate but, runner efficiency increases for some flow rate and almost constant thereafter. Efficiency and power developed by a runner drops quickly if turbine speed increases due to higher pressure losses and conversion of pressure energy to kinetic energy inside the runner. Increasing blade number increases power developed but, efficiency does not increase always. Efficiency increases for some blade number and drops down due to the fact that  change in direction of the relative flow vector at the runner exit, which decreases the net rotational momentum and increases the axial flow velocity.

  14. Multi-objective shape optimization of runner blade for Kaplan turbine

    International Nuclear Information System (INIS)

    Power machines LMZ, Saint Petersburg (Russian Federation))" data-affiliation=" (OJSC Power machines LMZ, Saint Petersburg (Russian Federation))" >Semenova, A; Power machines LMZ, Saint Petersburg (Russian Federation))" data-affiliation=" (OJSC Power machines LMZ, Saint Petersburg (Russian Federation))" >Pylev, I; Chirkov, D; Lyutov, A; Chemy, S; Skorospelov, V

    2014-01-01

    Automatic runner shape optimization based on extensive CFD analysis proved to be a useful design tool in hydraulic turbomachinery. Previously the authors developed an efficient method for Francis runner optimization. It was successfully applied to the design of several runners with different specific speeds. In present work this method is extended to the task of a Kaplan runner optimization. Despite of relatively simpler blade shape, Kaplan turbines have several features, complicating the optimization problem. First, Kaplan turbines normally operate in a wide range of discharges, thus CFD analysis of each variant of the runner should be carried out for several operation points. Next, due to a high specific speed, draft tube losses have a great impact on the overall turbine efficiency, and thus should be accurately evaluated. Then, the flow in blade tip and hub clearances significantly affects the velocity profile behind the runner and draft tube behavior. All these features are accounted in the present optimization technique. Parameterization of runner blade surface using 24 geometrical parameters is described in details. For each variant of runner geometry steady state three-dimensional turbulent flow computations are carried out in the domain, including wicket gate, runner, draft tube, blade tip and hub clearances. The objectives are maximization of efficiency in best efficiency and high discharge operation points, with simultaneous minimization of cavitation area on the suction side of the blade. Multiobjective genetic algorithm is used for the solution of optimization problem, requiring the analysis of several thousands of runner variants. The method is applied to optimization of runner shape for several Kaplan turbines with different heads

  15. Multi-objective shape optimization of runner blade for Kaplan turbine

    Science.gov (United States)

    Semenova, A.; Chirkov, D.; Lyutov, A.; Chemy, S.; Skorospelov, V.; Pylev, I.

    2014-03-01

    Automatic runner shape optimization based on extensive CFD analysis proved to be a useful design tool in hydraulic turbomachinery. Previously the authors developed an efficient method for Francis runner optimization. It was successfully applied to the design of several runners with different specific speeds. In present work this method is extended to the task of a Kaplan runner optimization. Despite of relatively simpler blade shape, Kaplan turbines have several features, complicating the optimization problem. First, Kaplan turbines normally operate in a wide range of discharges, thus CFD analysis of each variant of the runner should be carried out for several operation points. Next, due to a high specific speed, draft tube losses have a great impact on the overall turbine efficiency, and thus should be accurately evaluated. Then, the flow in blade tip and hub clearances significantly affects the velocity profile behind the runner and draft tube behavior. All these features are accounted in the present optimization technique. Parameterization of runner blade surface using 24 geometrical parameters is described in details. For each variant of runner geometry steady state three-dimensional turbulent flow computations are carried out in the domain, including wicket gate, runner, draft tube, blade tip and hub clearances. The objectives are maximization of efficiency in best efficiency and high discharge operation points, with simultaneous minimization of cavitation area on the suction side of the blade. Multiobjective genetic algorithm is used for the solution of optimization problem, requiring the analysis of several thousands of runner variants. The method is applied to optimization of runner shape for several Kaplan turbines with different heads.

  16. Gastrointestinal disturbances in marathon runners.

    Science.gov (United States)

    Riddoch, C; Trinick, T

    1988-06-01

    The purpose of this survey was to investigate the prevalence of running-induced gastrointestinal (GI) disturbances in marathon runners. A questionnaire was completed by 471 of the estimated 1,750 competitors in the 1986 Belfast City Marathon. Eighty-three per cent of respondents indicated that they occasionally or frequently suffered one or more GI disturbances during or immediately after running. The urge to have a bowel movement (53%) and diarrhoea (38%) were the most common symptoms, especially among female runners (74% and 68% respectively). Upper GI tract symptoms were experienced more by women than men (p less than 0.05) and more by younger runners than older runners (p less than 0.01). Women also suffered more lower GI tract symptoms than men (p less than 0.05) with younger runners showing a similar trend. Both upper and lower tract symptoms were more common during a "hard" run than an "easy" run (p less than 0.01) and were equally as common both during and after running. Of those runners who suffered GI disturbances, 72% thought that running was the cause and 29% believed their performance to be adversely affected. There was no consensus among sufferers as to the causes of symptoms and a wide variety of "remedies" were suggested. GI disturbances are common amongst long-distance runners and their aetiology is unknown. Medical practitioners should be aware of this when dealing with patients who run.

  17. Effect of age and performance on pacing of marathon runners

    Directory of Open Access Journals (Sweden)

    Nikolaidis PT

    2017-08-01

    Full Text Available Pantelis Theodoros Nikolaidis,1 Beat Knechtle2,3 1Exercise Physiology Laboratory, Attiki, Greece; 2Gesundheitszentrum St. Gallen, St. Gallen, 3Institute of Primary Care, University of Zurich, Zurich, Switzerland Abstract: Pacing strategies in marathon runners have previously been examined, especially with regard to age and performance level separately. However, less information about the age × performance interaction on pacing in age-group runners exists. The aim of the present study was to examine whether runners with similar race time and at different age differ for pacing. Data (women, n=117,595; men, n=180,487 from the “New York City Marathon” between 2006 and 2016 were analyzed. A between–within subjects analysis of variance showed a large main effect of split on race speed (p<0.001, η2=0.538 with the fastest speed in the 5–10 km split and the slowest in the 35–40 km. A small sex × split interaction on race speed was found (p<0.001, η2=0.035 with men showing larger increase in speed at 5 km and women at 25 km and 40 km (end spurt. An age-group × performance group interaction on Δspeed was shown for both sexes at 5 km, 10 km, 15 km, 20 km, 25 km, 30 km, 35 km, and 40 km (p<0.001, 0.001≤η2≤0.004, where athletes in older age-groups presented a relatively more even pace compared with athletes in younger age-groups, a trend that was more remarkable in the relatively slow performance groups. So far, the present study is the first one to observe an age × performance interaction on pacing; ie, older runners pace differently (smaller changes than younger runners with similar race time. These findings are of great practical interest for coaches working with marathon runners of different age, but similar race time. Keywords: running, master athlete, endurance, aerobic capacity, fatigue, gender, race time

  18. ANTHROPOMETRIC, GAIT AND STRENGTH CHARACTERISTICS OF KENYAN DISTANCE RUNNERS

    Directory of Open Access Journals (Sweden)

    Pui W. Kong

    2008-12-01

    Full Text Available This study intended to take a biomechanical approach to understand the success of Kenyan distance runners. Anthropometric, gait and lower extremity strength characteristics of six elite Kenyan distance runners were analyzed. Stride frequency, relative stride length and ground contact time were measured at five running speeds (3.5 - 5.4 m/s using a motion capture system. Isometric knee extension and flexion torques were measured at six angles and hamstrings and quadriceps (H:Q ratios at three angular velocities were determined using an isokinetic dynamometer. These runners were characterized by a low body mass index (20.1 ± 1.8 kg·m- 2, low percentage body fat (5.1 ± 1.6% and small calf circumference (34.5 ± 2.3 cm. At all running speeds, the ground contact time was shorter (p < 0.05 during right (170 - 212 ms compared to left (177 - 220 ms foot contacts. No bilateral difference was observed in other gait or strength variables. Their maximal isometric strength was lower than other runners (knee extension: 1.4 - 2.6 Nm·kg-1, knee flexion: 1.0 - 1.4 Nm·kg-1 but their H:Q ratios were higher than athletes in other sports (1.03 ± 0.51 at 60o/s, 1.44 ± 0.46 at 120o/s, 1.59 ± 0.66 at 180o/s. The slim limbs of Kenyan distance runners may positively contribute to performance by having a low moment of inertia and thus requiring less muscular effort in leg swing. The short ground contact time observed may be related to good running economy since there is less time for the braking force to decelerate forward motion of the body. These runners displayed minor gait asymmetry, though the difference may be too small to be practically significant. Further investigations are needed to confirm whether the bilateral symmetry in strength and high H:Q ratios are related to genetics, training or the lack of injuries in these runners

  19. Running Economy: Neuromuscular and Joint Stiffness Contributions in Trained Runners.

    Science.gov (United States)

    Tam, Nicholas; Tucker, Ross; Santos-Concejero, Jordan; Prins, Danielle; Lamberts, Robert P

    2018-05-29

    It is debated whether running biomechanics make good predictors of running economy, with little known information about the neuromuscular and joint stiffness contributions to economical running gait. The aim of this study was to understand the relationship between certain neuromuscular and spatiotemporal biomechanical factors associated with running economy. Thirty trained runners performed a 6-minute constant-speed running set at 3.3 m∙s -1 , where oxygen consumption was assessed. Overground running trials were also performed at 3.3 m∙s -1 to assess kinematics, kinetics and muscle activity. Spatiotemporal gait variables, joint stiffness, pre-activation and stance phase muscle activity (gluteus medius; rectus femoris (RF); biceps femoris(BF); peroneus longus (PL); tibialis anterior (TA); gastrocnemius lateralis and medius (LG and MG) were variables of specific interest and thus determined. Additionally, pre-activation and ground contact of agonist:antagonist co-activation were calculated. More economical runners presented with short ground contact times (r=0.639, p<0.001) and greater strides frequencies (r=-0.630, p<0.001). Lower ankle and greater knee stiffness were associated with lower oxygen consumption (r=0.527, p=0.007 & r=0.384, p=0.043, respectively). Only LG:TA co-activation during stance were associated with lower oxygen cost of transport (r=0.672, p<0.0001). Greater muscle pre-activation and bi-articular muscle activity during stance were associated with more economical runners. Consequently, trained runners who exhibit greater neuromuscular activation prior to and during ground contact, in turn optimise spatiotemporal variables and joint stiffness, will be the most economical runners.

  20. Adolescent runners: the effect of training shoes on running kinematics.

    Science.gov (United States)

    Mullen, Scott; Toby, E Bruce

    2013-06-01

    The modern running shoe typically features a large cushioned heel intended to dissipate the energy at heel strike to the knees and hips. The purpose of this study was to evaluate the effect that shoes have upon the running biomechanics among competitive adolescent runners. We wish to answer the question of whether running style is altered in these athletes because of footwear. Twelve competitive adolescent athletes were recruited from local track teams. Each ran on a treadmill in large heel trainers, track flats, and barefoot. Four different speeds were used to test each athlete. The biomechanics were assessed with a motion capture system. Stride length, heel height during posterior swing phase, and foot/ground contact were recorded. Shoe type markedly altered the running biomechanics. The foot/ground contact point showed differences in terms of footwear (Ptrainers, the athletes landed on their heels 69.79% of the time at all speeds (Ptrainers promote a heel strike pattern, whereas track flats and barefoot promote a forefoot or midfoot strike pattern. Training in heavily cushioned trainers by the competitive runner has not been clearly shown to be detrimental to performance, but it does change the gait pattern. It is not known whether the altered biomechanics of the heavily heeled cushioned trainer may be detrimental to the adolescent runner who is still developing a running style.

  1. Skeletal muscle plasticity with marathon training in novice runners.

    Science.gov (United States)

    Luden, N; Hayes, E; Minchev, K; Louis, E; Raue, U; Conley, T; Trappe, S

    2012-10-01

    The purpose of this study was to investigate leg muscle adaptation in runners preparing for their first marathon. Soleus and vastus lateralis (VL) biopsies were obtained from six recreational runners (23 ± 1 years, 61 ± 3 kg) before (T1), after 13 weeks of run training (T2), and after 3 weeks of taper and marathon (T3). Single muscle fiber size, contractile function (strength, speed, and power) and oxidative enzyme activity [citrate synthase (CS)] were measured at all three time points, and fiber type distribution was determined before and after the 16-week intervention. Training increased VO(2max) ∼9% (Pmarathon training elicits very specific skeletal muscle adaptations that likely support the ability to perform 42.2 km of continuous running - further strengthening the existing body of evidence for skeletal muscle specificity. © 2011 John Wiley & Sons A/S.

  2. Initiating running barefoot: Effects on muscle activation and impact accelerations in habitually rearfoot shod runners.

    Science.gov (United States)

    Lucas-Cuevas, Angel Gabriel; Priego Quesada, José Ignacio; Giménez, José Vicente; Aparicio, Inma; Jimenez-Perez, Irene; Pérez-Soriano, Pedro

    2016-11-01

    Runners tend to shift from a rearfoot to a forefoot strike pattern when running barefoot. However, it is unclear how the first attempts at running barefoot affect habitually rearfoot shod runners. Due to the inconsistency of their recently adopted barefoot technique, a number of new barefoot-related running injuries are emerging among novice barefoot runners. The aim of this study was therefore to analyse the influence of three running conditions (natural barefoot [BF], barefoot with a forced rearfoot strike [BRS], and shod [SH]) on muscle activity and impact accelerations in habitually rearfoot shod runners. Twenty-two participants ran at 60% of their maximal aerobic speed while foot strike, tibial and head impact accelerations, and tibialis anterior (TA), peroneus longus (PL), gastrocnemius medialis (GM) and gastrocnemius lateralis (GL) muscle activity were registered. Only 68% of the runners adopted a non-rearfoot strike pattern during BF. Running BF led to a reduction of TA activity as well as to an increase of GL and GM activity compared to BRS and SH. Furthermore, BRS increased tibial peak acceleration, tibial magnitude and tibial acceleration rate compared to SH and BF. In conclusion, 32% of our runners showed a rearfoot strike pattern at the first attempts at running barefoot, which corresponds to a running style (BRS) that led to increased muscle activation and impact accelerations and thereby to a potentially higher risk of injury compared to running shod.

  3. CERN runners scale new heights

    CERN Multimedia

    2002-01-01

    Part of the field in the men's over-50 categories. Gordon Lee (IT) is in the white top, just behind the runner in yellow in the centre of the photo. On a bright and sunny 1 December last, a team from CERN lifted the honours for the company team event of Switzerland's most popular running race. The occasion was the 24th 'Course de l'Escalade'. The Escalade races wind through the narrow streets of Geneva's Old Town, lined with friends and well-wishers for the event. Since they began in 1978, they have become so popular that the Escalade now ranks among the largest popular running events in Europe. Some 19000 people aged from 5 to 85 donned running shoes to brave the crowds last December. Clearly, not all could run at once, so races by category started at 11am and continued until after 7pm. Distances ranged from about 2 km for the youngest children to 7.5 km for the men's categories. 100 or so runners, men and women, from the top international elite were invited for the race. CERN runners had a double reason t...

  4. Excellent results for CERN runners

    CERN Multimedia

    Hervé Cornet, CERN Running club

    2015-01-01

    As in previous years, thirty or so runners from CERN took part in the Tour du Canton de Genève (more information here, in French only).   The men’s team that won the corporate challenge prize in the Tour du Canton de Genève: (standing, left to right) Patrick Villeton, Phil Hebda, Mika Vesterinen, Steffen Doebert; (sitting, left to right) Guillaume Michet and Camille Ruiz-Llamas. The Laboratory was represented in the corporate challenge by five teams, one of which came first in the men’s category. CERN’s other teams also put in good performances, with one finishing fourth in the men's category and another seventh in the mixed category. Runners from CERN did well in the individual classifications too. All the results can be found here. The Maxi Race team: (left to right) Sebastien Ponce, Alain Cauphy, Klaus Hanke and Christophe Biot. Elsewhere, four CERN runners competed in the finals of the Annecy Maxi Race (site in French only...

  5. Predictor variables for marathon race time in recreational female runners.

    Science.gov (United States)

    Schmid, Wiebke; Knechtle, Beat; Knechtle, Patrizia; Barandun, Ursula; Rüst, Christoph Alexander; Rosemann, Thomas; Lepers, Romuald

    2012-06-01

    We intended to determine predictor variables of anthropometry and training for marathon race time in recreational female runners in order to predict marathon race time for future novice female runners. Anthropometric characteristics such as body mass, body height, body mass index, circumferences of limbs, thicknesses of skin-folds and body fat as well as training variables such as volume and speed in running training were related to marathon race time using bi- and multi-variate analysis in 29 female runners. The marathoners completed the marathon distance within 251 (26) min, running at a speed of 10.2 (1.1) km/h. Body mass (r=0.37), body mass index (r=0.46), the circumferences of thigh (r=0.51) and calf (r=0.41), the skin-fold thicknesses of front thigh (r=0.38) and of medial calf (r=0.40), the sum of eight skin-folds (r=0.44) and body fat percentage (r=0.41) were related to marathon race time. For the variables of training, maximal distance ran per week (r=- 0.38), number of running training sessions per week (r=- 0.46) and the speed of the training sessions (r= - 0.60) were related to marathon race time. In the multi-variate analysis, the circumference of calf (P=0.02) and the speed of the training sessions (P=0.0014) were related to marathon race time. Marathon race time might be partially (r(2)=0.50) predicted by the following equation: Race time (min)=184.4 + 5.0 x (circumference calf, cm) -11.9 x (speed in running during training, km/h) for recreational female marathoners. Variables of both anthropometry and training were related to marathon race time in recreational female marathoners and cannot be reduced to one single predictor variable. For practical applications, a low circumference of calf and a high running speed in training are associated with a fast marathon race time in recreational female runners.

  6. Is the rearfoot pattern the most frequently foot strike pattern among recreational shod distance runners?

    Science.gov (United States)

    de Almeida, Matheus Oliveira; Saragiotto, Bruno Tirotti; Yamato, Tiê Parma; Lopes, Alexandre Dias

    2015-02-01

    To determine the distribution of the foot strike patterns among recreational shod runners and to compare the personal and training characteristics between runners with different foot strike patterns. Cross-sectional study. Areas of running practice in São Paulo, Brazil. 514 recreational shod runners older than 18 years and free of injury. Foot strike patterns were evaluated with a high-speed camera (250 Hz) and photocells to assess the running speed of participants. Personal and training characteristics were collected through a questionnaire. The inter-rater reliability of the visual foot strike pattern classification method was 96.7% and intra-rater reliability was 98.9%. 95.1% (n = 489) of the participants were rearfoot strikers, 4.1% (n = 21) were midfoot strikers, and four runners (0.8%) were forefoot strikers. There were no significant differences between strike patterns for personal and training characteristics. This is the first study to demonstrate that almost all recreational shod runners were rearfoot strikers. The visual method of evaluation seems to be a reliable and feasible option to classify foot strike pattern. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Peripheral neuropathy

    Science.gov (United States)

    ... peripheral; Neuritis - peripheral; Nerve disease; Polyneuropathy; Chronic pain - peripheral neuropathy ... Philadelphia, PA: Elsevier; 2016:chap 107. Shy ME. Peripheral neuropathies. In: Goldman L, Schafer AI, eds. Goldman's Cecil ...

  8. Effects of Strength Training on Postpubertal Adolescent Distance Runners.

    Science.gov (United States)

    Blagrove, Richard C; Howe, Louis P; Cushion, Emily J; Spence, Adam; Howatson, Glyn; Pedlar, Charles R; Hayes, Philip R

    2018-06-01

    Strength training activities have consistently been shown to improve running economy (RE) and neuromuscular characteristics, such as force-producing ability and maximal speed, in adult distance runners. However, the effects on adolescent (training on several important physiological and neuromuscular qualities associated with distance running performance. Participants (n = 25, 13 female, 17.2 ± 1.2 yr) were paired according to their sex and RE and randomly assigned to a 10-wk strength training group (STG) or a control group who continued their regular training. The STG performed twice weekly sessions of plyometric, sprint, and resistance training in addition to their normal running. Outcome measures included body mass, maximal oxygen uptake (V˙O2max), speed at V˙O2max, RE (quantified as energy cost), speed at fixed blood lactate concentrations, 20-m sprint, and maximal voluntary contraction during an isometric quarter-squat. Eighteen participants (STG: n = 9, 16.1 ± 1.1 yr; control group: n = 9, 17.6 ± 1.2 yr) completed the study. The STG displayed small improvements (3.2%-3.7%; effect size (ES), 0.31-0.51) in RE that were inferred as "possibly beneficial" for an average of three submaximal speeds. Trivial or small changes were observed for body composition variables, V˙O2max and speed at V˙O2max; however, the training period provided likely benefits to speed at fixed blood lactate concentrations in both groups. Strength training elicited a very likely benefit and a possible benefit to sprint time (ES, 0.32) and maximal voluntary contraction (ES, 0.86), respectively. Ten weeks of strength training added to the program of a postpubertal distance runner was highly likely to improve maximal speed and enhances RE by a small extent, without deleterious effects on body composition or other aerobic parameters.

  9. Bone Stress Injuries in Runners.

    Science.gov (United States)

    Tenforde, Adam S; Kraus, Emily; Fredericson, Michael

    2016-02-01

    Bone stress injuries (BSIs) are common running injuries and may occur at a rate of 20% annually. Both biological and biomechanical risk factors contribute to BSI. Evaluation of a runner with suspected BSI includes completing an appropriate history and physical examination. MRI grading classification for BSI has been proposed and may guide return to play. Management includes activity modification, optimizing nutrition, and addressing risk factors, including the female athlete triad. BSI prevention strategies include screening for risk factors during preparticipation evaluations, optimizing nutrition (including adequate caloric intake, calcium, and vitamin D), and promoting ball sports during childhood and adolescence. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Muscular Calf Injuries in Runners.

    Science.gov (United States)

    Fields, Karl B; Rigby, Michael D

    2016-01-01

    Calf pain is a common complaint among runners of all ages but is most frequent in masters athletes. This article focuses on injuries to the triceps surae or true 'calf muscles.' The most common calf injury is a tear of the medial gastrocnemius muscle (Tennis Leg) but other structures including the lateral gastrocnemius, plantaris and soleus also may be the cause of muscular pain. This article looks at the presentation, evaluation, and treatment of these injuries. We also highlight some examples of musculoskeletal ultrasound which is a valuable tool for rapid diagnosis of the cause and extent of injury.

  11. Prediction of half-marathon race time in recreational female and male runners

    OpenAIRE

    Knechtle, Beat; Barandun, Ursula; Knechtle, Patrizia; Zingg, Matthias A; Rosemann, Thomas; Rüst, Christoph A

    2014-01-01

    Half-marathon running is of high popularity. Recent studies tried to find predictor variables for half-marathon race time for recreational female and male runners and to present equations to predict race time. The actual equations included running speed during training for both women and men as training variable but midaxillary skinfold for women and body mass index for men as anthropometric variable. An actual study found that percent body fat and running speed during training sessions were ...

  12. Is There an Optimal Speed for Economical Running?

    Science.gov (United States)

    Black, Matthew I; Handsaker, Joseph C; Allen, Sam J; Forrester, Stephanie E; Folland, Jonathan P

    2018-01-01

    The influence of running speed and sex on running economy is unclear and may have been confounded by measurements of oxygen cost that do not account for known differences in substrate metabolism, across a limited range of speeds, and differences in performance standard. Therefore, this study assessed the energy cost of running over a wide range of speeds in high-level and recreational runners to investigate the effect of speed (in absolute and relative terms) and sex (men vs women of equivalent performance standard) on running economy. To determine the energy cost (kcal · kg -1  · km -1 ) of submaximal running, speed at lactate turn point (sLTP), and maximal rate of oxygen uptake, 92 healthy runners (high-level men, n = 14; high-level women, n = 10; recreational men, n = 35; recreational women, n = 33) completed a discontinuous incremental treadmill test. There were no sex-specific differences in the energy cost of running for the recreational or high-level runners when compared at absolute or relative running speeds (P > .05). The absolute and relative speed-energy cost relationships for the high-level runners demonstrated a curvilinear U shape with a nadir reflecting the most economical speed at 13 km/h or 70% sLTP. The high-level runners were more economical than the recreational runners at all absolute and relative running speeds (P running, there is no sex-specific difference, and high-level endurance runners exhibit better running economy than recreational endurance runners.

  13. Physiological and training characteristics of recreational marathon runners.

    Science.gov (United States)

    Gordon, Dan; Wightman, Sarah; Basevitch, Itay; Johnstone, James; Espejo-Sanchez, Carolina; Beckford, Chelsea; Boal, Mariette; Scruton, Adrian; Ferrandino, Mike; Merzbach, Viviane

    2017-01-01

    The aim of this study was to examine the physical and training characteristics of recreational marathon runners within finish time bandings (2.5-3 h, 3-3.5 h, 3.5-4 h, 4-4.5 h and >4.5 h). A total of 97 recreational marathon runners (age 42.4 ± 9.9 years; mass 69.2 ± 11.3 kg; stature 172.8 ± 9.1 cm), with a marathon finish time of 229.1 ± 48.7 min, of whom n = 34 were female and n = 63 were male, completed an incremental treadmill test for the determination of lactate threshold (LT1), lactate turn point (LT2) and running economy (RE). Following a 7-min recovery, they completed a test to volitional exhaustion starting at LT2 for the assessment of [Formula: see text]. In addition, all participants completed a questionnaire gathering information on their current training regimes exploring weekly distances, training frequencies, types of sessions, longest run in a week, with estimations of training speed, and load and volume derived from these data. Training frequency was shown to be significantly greater for the 2.5-3 h group compared to the 3.5-4 h runners ( P 4.5 h group ( P = 0.004), while distance per session (km·session -1 ) was significantly greater for the 2.5-3 h group (16.1 ± 4.2) compared to the 3.5-4 h group (15.5 ± 5.2; P = 0.01) and >4.5 h group (10.3 ± 2.6; P = 0.001). Race speed correlated with LT1 ( r = 0.791), LT2 ( r = 0.721) and distance per session ( r = 0.563). The data highlight profound differences for key components of marathon running ([Formula: see text], LT1, LT2, RE and % [Formula: see text]) within a group of recreational runners with the discriminating training variables being training frequency and the absolute training speed.

  14. Design optimization of axial flow hydraulic turbine runner: Part II - multi-objective constrained optimization method

    Science.gov (United States)

    Peng, Guoyi; Cao, Shuliang; Ishizuka, Masaru; Hayama, Shinji

    2002-06-01

    This paper is concerned with the design optimization of axial flow hydraulic turbine runner blade geometry. In order to obtain a better design plan with good performance, a new comprehensive performance optimization procedure has been presented by combining a multi-variable multi-objective constrained optimization model with a Q3D inverse computation and a performance prediction procedure. With careful analysis of the inverse design of axial hydraulic turbine runner, the total hydraulic loss and the cavitation coefficient are taken as optimization objectives and a comprehensive objective function is defined using the weight factors. Parameters of a newly proposed blade bound circulation distribution function and parameters describing positions of blade leading and training edges in the meridional flow passage are taken as optimization variables.The optimization procedure has been applied to the design optimization of a Kaplan runner with specific speed of 440 kW. Numerical results show that the performance of designed runner is successfully improved through optimization computation. The optimization model is found to be validated and it has the feature of good convergence. With the multi-objective optimization model, it is possible to control the performance of designed runner by adjusting the value of weight factors defining the comprehensive objective function. Copyright

  15. Ankle plantarflexion strength in rearfoot and forefoot runners: a novel clusteranalytic approach.

    Science.gov (United States)

    Liebl, Dominik; Willwacher, Steffen; Hamill, Joseph; Brüggemann, Gert-Peter

    2014-06-01

    The purpose of the present study was to test for differences in ankle plantarflexion strengths of habitually rearfoot and forefoot runners. In order to approach this issue, we revisit the problem of classifying different footfall patterns in human runners. A dataset of 119 subjects running shod and barefoot (speed 3.5m/s) was analyzed. The footfall patterns were clustered by a novel statistical approach, which is motivated by advances in the statistical literature on functional data analysis. We explain the novel statistical approach in detail and compare it to the classically used strike index of Cavanagh and Lafortune (1980). The two groups found by the new cluster approach are well interpretable as a forefoot and a rearfoot footfall groups. The subsequent comparison study of the clustered subjects reveals that runners with a forefoot footfall pattern are capable of producing significantly higher joint moments in a maximum voluntary contraction (MVC) of their ankle plantarflexor muscles tendon units; difference in means: 0.28Nm/kg. This effect remains significant after controlling for an additional gender effect and for differences in training levels. Our analysis confirms the hypothesis that forefoot runners have a higher mean MVC plantarflexion strength than rearfoot runners. Furthermore, we demonstrate that our proposed stochastic cluster analysis provides a robust and useful framework for clustering foot strikes. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Foot strike patterns of runners at the 15-km point during an elite-level half marathon.

    Science.gov (United States)

    Hasegawa, Hiroshi; Yamauchi, Takeshi; Kraemer, William J

    2007-08-01

    There are various recommendations by many coaches regarding foot landing techniques in distance running that are meant to improve running performance and prevent injuries. Several studies have investigated the kinematic and kinetic differences between rearfoot strike (RFS), midfoot strike (MFS), and forefoot strike (FFS) patterns at foot landing and their effects on running efficiency on a treadmill and over ground conditions. However, little is known about the actual condition of the foot strike pattern during an actual road race at the elite level of competition. The purpose of the present study was to document actual foot strike patterns during a half marathon in which elite international level runners, including Olympians, compete. Four hundred fifteen runners were filmed by 2 120-Hz video cameras in the height of 0.15 m placed at the 15.0-km point and obtained sagittal foot landing and taking off images for 283 runners. Rearfoot strike was observed in 74.9% of all analyzed runners, MFS in 23.7%, and FFS in 1.4%. The percentage of MFS was higher in the faster runners group, when all runners were ranked and divided into 50 runner groups at the 15.0-km point of the competition. In the top 50, which included up to the 69th place runner in actual order who passed the 15-km point at 45 minutes, 53 second (this speed represents 5.45 m x s(-1), or 15 minutes, 17 seconds per 5 km), RFS, MFS, and FFS were 62.0, 36.0, and 2.0%, respectively. Contact time (CT) clearly increased for the slower runners, or the placement order increased (r = 0.71, p strike was observed in 42% of all runners. The percentage of INV for MFS was higher than for RFS and FFS (62.5, 32.0, and 50%, respectively). The CT with INV for MFS + FFS was significantly shorter than the CT with and without INV for RFS. Furthermore, the CT with INV was significantly shorter than push-off time without INV for RFS. The findings of this study indicate that foot strike patterns are related to running speed. The

  17. Arming and firing system for DISTANT RUNNER

    International Nuclear Information System (INIS)

    Skenandore, L.H.; Johnson, J.P.

    1982-01-01

    Sandia A and F systems Division 1132 provided arming and firing support for the DISTANT RUNNER Test Program at White Sands Missile Range. This report describes the field support and the firing system that was used

  18. New parameters influencing hydraulic runner lifetime

    International Nuclear Information System (INIS)

    Sabourin, M; Bouffard, D A; Thibault, D; Levesque, M

    2010-01-01

    Traditionally, hydraulic runner mechanical design is based on calculation of static stresses. Today, validation of hydraulic runner design in terms of reliability requires taking into account the fatigue effect of dynamics loads. A damage tolerant approach based on fracture mechanics is the method chosen by Alstom and Hydro-Quebec to study fatigue damage in runners. This requires a careful examination of all factors influencing material fatigue behavior. Such material behavior depends mainly on the chemical composition, microstructure and thermal history of the component, and on the resulting residual stresses. Measurement of fracture mechanics properties of various steels have demonstrated that runner lifetime can be significantly altered by differences in the manufacturing process, although remaining in accordance with agreed practices and standards such as ASTM. Carbon content and heat treatment are suspected to influence fatigue lifetime. This will have to be investigated by continuing the current research.

  19. New parameters influencing hydraulic runner lifetime

    Energy Technology Data Exchange (ETDEWEB)

    Sabourin, M; Bouffard, D A [Alstom Hydro Canada Inc, Hydraulic Engineering, 1350 chemin St-Roch, Sorel-Tracy (Quebec), J3P 5P9 (Canada); Thibault, D [Hydro-Quebec, Institut de Recherche d' Hydro-Quebec 1800 boul. Lionel-Boulet, Varennes (Quebec), J3X 1S1 (Canada); Levesque, M, E-mail: michel.sabourin@power.alstom.co [Ecole Polytechnique de Montreal, Departement de genie mecanique C.P.6079, succ. Centre-ville, Montreal (Quebec), H3C 3A7 (Canada)

    2010-08-15

    Traditionally, hydraulic runner mechanical design is based on calculation of static stresses. Today, validation of hydraulic runner design in terms of reliability requires taking into account the fatigue effect of dynamics loads. A damage tolerant approach based on fracture mechanics is the method chosen by Alstom and Hydro-Quebec to study fatigue damage in runners. This requires a careful examination of all factors influencing material fatigue behavior. Such material behavior depends mainly on the chemical composition, microstructure and thermal history of the component, and on the resulting residual stresses. Measurement of fracture mechanics properties of various steels have demonstrated that runner lifetime can be significantly altered by differences in the manufacturing process, although remaining in accordance with agreed practices and standards such as ASTM. Carbon content and heat treatment are suspected to influence fatigue lifetime. This will have to be investigated by continuing the current research.

  20. Fat intake and injury in female runners.

    Science.gov (United States)

    Gerlach, Kristen E; Burton, Harold W; Dorn, Joan M; Leddy, John J; Horvath, Peter J

    2008-01-03

    Our purpose was to determine the relationship between energy intake, energy availability, dietary fat and lower extremity injury in adult female runners. We hypothesized that runners who develop overuse running-related injuries have lower energy intakes, lower energy availability and lower fat intake compared to non-injured runners. Eighty-six female subjects, running a minimum of 20 miles/week, completed a food frequency questionnaire and informed us about injury incidence over the next year. Injured runners had significantly lower intakes of total fat (63 +/- 20 vs. 80 +/- 50 g/d) and percentage of kilocalories from fat (27 +/- 5 vs. 30 +/- 8 %) compared with non-injured runners. A logistic regression analysis found that fat intake was the best dietary predictor, correctly identifying 64% of future injuries. Lower energy intake and lower energy availability approached, but did not reach, a significant association with overuse injury in this study. Fat intake is likely associated with injury risk in female runners. By documenting these associations, better strategies can be developed to reduce running injuries in women.

  1. Fat intake and injury in female runners

    Directory of Open Access Journals (Sweden)

    Leddy John J

    2008-01-01

    Full Text Available Abstract Background Our purpose was to determine the relationship between energy intake, energy availability, dietary fat and lower extremity injury in adult female runners. We hypothesized that runners who develop overuse running-related injuries have lower energy intakes, lower energy availability and lower fat intake compared to non-injured runners. Methods Eighty-six female subjects, running a minimum of 20 miles/week, completed a food frequency questionnaire and informed us about injury incidence over the next year. Results Injured runners had significantly lower intakes of total fat (63 ± 20 vs. 80 ± 50 g/d and percentage of kilocalories from fat (27 ± 5 vs. 30 ± 8 % compared with non-injured runners. A logistic regression analysis found that fat intake was the best dietary predictor, correctly identifying 64% of future injuries. Lower energy intake and lower energy availability approached, but did not reach, a significant association with overuse injury in this study. Conclusion Fat intake is likely associated with injury risk in female runners. By documenting these associations, better strategies can be developed to reduce running injuries in women.

  2. The Influence of runner system on production of injection molds

    Directory of Open Access Journals (Sweden)

    Janostik Vaclav

    2016-01-01

    Full Text Available This experimental study describes the influence of runner system on rheological properties during the injection molding process. Economic effects on the amount of production are discussed as well. Autodesk Moldflow Synergy 2016 (Moldflow was used for the study of the injection process. Three suggestions of the runner system, cold runner system, hot runner system and the combination of cold–hot runner system have been promoted. These three variants underwent the rheological and economic analysis. As a result, recommendations for the application of the runner system for the required amount of production have been suggested

  3. Do Running Kinematic Characteristics Change over a Typical HIIT for Endurance Runners?

    Science.gov (United States)

    García-Pinillos, Felipe; Soto-Hermoso, Víctor M; Latorre-Román, Pedro Á

    2016-10-01

    García-Pinillos, F, Soto-Hermoso, VM, and Latorre-Román, PÁ. Do running kinematic characteristics change over a typical HIIT for endurance runners?. J Strength Cond Res 30(10): 2907-2917, 2016-The purpose of this study was to describe kinematic changes that occur during a common high-intensity intermittent training (HIIT) session for endurance runners. Twenty-eight male endurance runners participated in this study. A high-speed camera was used to measure sagittal-plane kinematics at the first and the last run during a HIIT (4 × 3 × 400 m). The dependent variables were spatial-temporal variables, joint angles during support and swing, and foot strike pattern. Physiological variables, rate of perceived exertion, and athletic performance were also recorded. No significant changes (p ≥ 0.05) in kinematic variables were found during the HIIT session. Two cluster analyses were performed, according to the average running pace-faster vs. slower, and according to exhaustion level reached-exhausted group vs. nonexhausted group (NEG). At first run, no significant differences were found between groups. As for the changes induced by the running protocol, significant differences (p ≤ 0.05) were found between faster and slower athletes at toe-off in θhip and θknee, whereas some changes were found in NEG in θhip during toe-off (+4.3°) and θknee at toe-off (-5.2°) during swing. The results show that a common HIIT session for endurance runners did not consistently or substantially perturb the running kinematics of trained male runners. Additionally, although some differences between groups have been found, neither athletic performance nor exhaustion level reached seems to be determinant in the kinematic response during a HIIT, at least for this group of moderately trained endurance runners.

  4. A statistical approach to the use of control entropy identifies differences in constraints of gait in highly trained versus untrained runners.

    Science.gov (United States)

    Parshad, Rana D; McGregor, Stephen J; Busa, Michael A; Skufca, Joseph D; Bollt, Erik

    2012-01-01

    Control entropy (CE) is a complexity analysis suitable for dynamic, non-stationary conditions which allows the inference of the control effort of a dynamical system generating the signal. These characteristics make CE a highly relevant time varying quantity relevant to the dynamic physiological responses associated with running. Using High Resolution Accelerometry (HRA) signals we evaluate here constraints of running gait, from two different groups of runners, highly trained collegiate and untrained runners. To this end,we further develop the control entropy (CE) statistic to allow for group analysis to examine the non-linear characteristics of movement patterns in highly trained runners with those of untrained runners, to gain insight regarding gaits that are optimal for running. Specifically, CE develops response time series of individuals descriptive of the control effort; a group analysis of these shapes developed here uses Karhunen Loeve Analysis (KL) modes of these time series which are compared between groups by application of a Hotelling T² test to these group response shapes. We find that differences in the shape of the CE response exist within groups, between axes for untrained runners (vertical vs anterior-posterior and mediolateral vs anterior-posterior) and trained runners (mediolateral vs anterior-posterior). Also shape differences exist between groups by axes (vertical vs mediolateral). Further, the CE, as a whole, was higher in each axis in trained vs untrained runners. These results indicate that the approach can provide unique insight regarding the differing constraints on running gait in highly trained and untrained runners when running under dynamic conditions. Further, the final point indicates trained runners are less constrained than untrained runners across all running speeds.

  5. Previous injuries and some training characteristics predict running-related injuries in recreational runners: a prospective cohort study.

    Science.gov (United States)

    Hespanhol Junior, Luiz Carlos; Pena Costa, Leonardo Oliveira; Lopes, Alexandre Dias

    2013-12-01

    What is the incidence of running-related injuries (RRIs) in recreational runners? Which personal and training characteristics predict RRIs in recreational runners? Prospective cohort study. A total of 200 recreational runners answered a fortnightly online survey containing questions about their running routine, races, and presence of RRI. These runners were followed-up for a period of 12 weeks. The primary outcome of this study was running-related injury. The incidence of injuries was calculated taking into account the exposure to running and was expressed by RRI/1000 hours. The association between potential predictive factors and RRIs was estimated using generalised estimating equation models. A total of 84 RRIs were registered in 60 (31%) of the 191 recreational runners who completed all follow-up surveys. Of the injured runners 30% (n=18/60) developed two or more RRIs, with 5/18 (28%) being recurrences. The incidence of RRI was 10 RRI/1000 hours of running exposure. The main type of RRI observed was muscle injuries (30%, n=25/84). The knee was the most commonly affected anatomical region (19%, n=16/84). The variables associated with RRI were: previous RRI (OR 1.88, 95% CI 1.01 to 3.51), duration of training although the effect was very small (OR 1.01, 95% CI 1.00 to 1.02), speed training (OR 1.46, 95% CI 1.02 to 2.10), and interval training (OR 0.61, 95% CI 0.43 to 0.88). Physiotherapists should be aware and advise runners that past RRI and speed training are associated with increased risk of further RRI, while interval training is associated with lower risk, although these associations may not be causative. Copyright © 2013 Australian Physiotherapy Association. Published by Elsevier B.V. All rights reserved.

  6. Physiological and training characteristics of recreational marathon runners

    Directory of Open Access Journals (Sweden)

    Gordon D

    2017-11-01

    Full Text Available Dan Gordon,1 Sarah Wightman,2 Itay Basevitch,1 James Johnstone,1 Carolina Espejo-Sanchez,1 Chelsea Beckford,1 Mariette Boal,1 Adrian Scruton,1 Mike Ferrandino,1 Viviane Merzbach1 1Cambridge Centre for Sport and Exercise Sciences, Anglia Ruskin University, 2The Flying Runner, Cambridge, UK Purpose: The aim of this study was to examine the physical and training characteristics of recreational marathon runners within finish time bandings (2.5–3 h, 3–3.5 h, 3.5–4 h, 4–4.5 h and >4.5 h.Materials and methods: A total of 97 recreational marathon runners (age 42.4 ± 9.9 years; mass 69.2 ± 11.3 kg; stature 172.8 ± 9.1 cm, with a marathon finish time of 229.1 ± 48.7 min, of whom n = 34 were female and n = 63 were male, completed an incremental treadmill test for the determination of lactate threshold (LT1, lactate turn point (LT2 and running economy (RE. Following a 7-min recovery, they completed a test to volitional exhaustion starting at LT2 for the assessment of VO2max. In addition, all participants completed a questionnaire gathering information on their current training regimes exploring weekly distances, training frequencies, types of sessions, longest run in a week, with estimations of training speed, and load and volume derived from these data.Results: Training frequency was shown to be significantly greater for the 2.5–3 h group compared to the 3.5–4 h runners (P < 0.001 and >4.5 h group (P = 0.004, while distance per session (km⋅session–1 was significantly greater for the 2.5–3 h group (16.1 ± 4.2 compared to the 3.5–4 h group (15.5 ± 5.2; P = 0.01 and >4.5 h group (10.3 ± 2.6; P = 0.001. Race speed correlated with LT1 (r = 0.791, LT2 (r = 0.721 and distance per session (r = 0.563.Conclusion: The data highlight profound differences for key components of marathon running (VO2max, LT1, LT2, RE and % VO2max within a group of recreational runners with the discriminating training variables being training

  7. Ultramarathon runners: nature or nurture?

    Science.gov (United States)

    Knechtle, Beat

    2012-12-01

    Ultramarathon running is increasingly popular. An ultramarathon is defined as a running event involving distances longer than the length of a traditional marathon of 42.195 km. In ultramarathon races, ~80% of the finishers are men. Ultramarathoners are typically ~45 y old and achieve their fastest running times between 30 and 49 y for men, and between 30 and 54 y for women. Most probably, ultrarunners start with a marathon before competing in an ultramarathon. In ultramarathoners, the number of previously completed marathons is significantly higher than the number of completed marathons in marathoners. However, recreational marathoners have a faster personal-best marathon time than ultramarathoners. Successful ultramarathoners have 7.6 ± 6.3 y of experience in ultrarunning. Ultramarathoners complete more running kilometers in training than marathoners do, but they run more slowly during training than marathoners. To summarize, ultramarathoners are master runners, have a broad experience in running, and prepare differently for an ultramarathon than marathoners do. However, it is not known what motivates male ultramarathoners and where ultramarathoners mainly originate. Future studies need to investigate the motivation of male ultramarathoners, where the best ultramarathoners originate, and whether they prepare by competing in marathons before entering ultramarathons.

  8. Relay Runners Catch The Rays

    CERN Multimedia

    2004-01-01

    Athletes sizzled around CERN on Wednesday 19 May at the 34th annual relay race. On one of the warmest days of the year so far, sunkissed competitors ran for the finish line and then straight for the drinks table. The Shabbys were on fire again, hurtling across the line first in a time of 10 min. 42.6 sec. and making an even stronger claim to being hailed as the traditional winners of the race with their fourth triumph in a row. Also on form were the Lynx Runners who won the Veteran's trophy, continuing their winning ways since 2002 and placing 29th overall. Ildefons Magrans of the ALICE Quarks on the Loose team ran the fastest 1000m in a time of 2 min. 47 sec. Second-placed Charmilles Technologies won the Open category in a time of 11 min. 03 sec., taking the prize for teams whose members work in different departments or who come from outside CERN. The OPALadies won the women's trophy and placed 48th. With 9 trophies up for grabs, more than 300 people in 55 teams ran the fun run, covering distances of 1000m ...

  9. Rearfoot striking runners are more economical than midfoot strikers.

    Science.gov (United States)

    Ogueta-Alday, Ana; Rodríguez-Marroyo, José Antonio; García-López, Juan

    2014-03-01

    This study aimed to analyze the influence of foot strike pattern on running economy and biomechanical characteristics in subelite runners with a similar performance level. Twenty subelite long-distance runners participated and were divided into two groups according to their foot strike pattern: rearfoot (RF, n = 10) and midfoot (MF, n = 10) strikers. Anthropometric characteristics were measured (height, body mass, body mass index, skinfolds, circumferences, and lengths); physiological (VO2max, anaerobic threshold, and running economy) and biomechanical characteristics (contact and flight times, step rate, and step length) were registered during both incremental and submaximal tests on a treadmill. There were no significant intergroup differences in anthropometrics, VO2max, or anaerobic threshold measures. RF strikers were 5.4%, 9.3%, and 5.0% more economical than MF at submaximal speeds (11, 13, and 15 km·h respectively, although the difference was not significant at 15 km·h, P = 0.07). Step rate and step length were not different between groups, but RF showed longer contact time (P Foot strike pattern affected both contact and flight times, which may explain the differences in running economy.

  10. Lower extremity injuries in runners. Advances in prediction.

    Science.gov (United States)

    Macera, C A

    1992-01-01

    Recreational and competitive running is practised by many individuals to improve cardiorespiratory function and general well-being. The major negative aspect of running is the high rate of injuries to the lower extremities. Several well-designed population-based studies have found no major differences in injury rates between men and women; no increasing effect of age on injuries; a declining injury rate with more years of running experience; no substantial effect of weight or height; an uncertain effect of psychological factors; and a strong effect of previous injury on future injuries. Among the modifiable risk factors studied, weekly distance is the strongest predictor of future injuries. Other training characteristics (speed, frequency, surface, timing) have little or no effect on future injuries after accounting for distance run. More studies are needed to address the effects of appropriate stretching practices and abrupt change in training patterns. For recreational runners who have sustained injuries, especially within the past year, a reduction in running to below 32 km per week is recommended. For those about to begin a running programme, moderation is the best advice. For competitive runners, great care should be taken to ensure that prior injuries are sufficiently healed before attempting any racing event, particularly a marathon.

  11. Hydrodynamics automatic optimization of runner blades for reaction hydraulic turbines

    Science.gov (United States)

    Balint, D.; Câmpian, V.; Nedelcu, D.; Megheles, O.

    2012-11-01

    The aim of this paper is to optimize the hydrodynamics of the runner blades of hydraulic turbines. The runner presented is an axial Kaplan one, but the methodology is common also to Francis runners. The whole methodology is implemented in the in-house software QTurbo3D. The effect of the runner blades geometry modification upon its hydrodynamics is shown both from energetic and cavitation points of view.

  12. Hydrodynamics automatic optimization of runner blades for reaction hydraulic turbines

    International Nuclear Information System (INIS)

    Balint, D; Câmpian, V; Nedelcu, D; Megheles, O

    2012-01-01

    The aim of this paper is to optimize the hydrodynamics of the runner blades of hydraulic turbines. The runner presented is an axial Kaplan one, but the methodology is common also to Francis runners. The whole methodology is implemented in the in-house software QTurbo3D. The effect of the runner blades geometry modification upon its hydrodynamics is shown both from energetic and cavitation points of view.

  13. Heart rate variability in prediction of individual adaptation to endurance training in recreational endurance runners.

    Science.gov (United States)

    Vesterinen, V; Häkkinen, K; Hynynen, E; Mikkola, J; Hokka, L; Nummela, A

    2013-03-01

    The aim of this study was to investigate whether nocturnal heart rate variability (HRV) can be used to predict changes in endurance performance during 28 weeks of endurance training. The training was divided into 14 weeks of basic training (BTP) and 14 weeks of intensive training periods (ITP). Endurance performance characteristics, nocturnal HRV, and serum hormone concentrations were measured before and after both training periods in 28 recreational endurance runners. During the study peak treadmill running speed (Vpeak ) improved by 7.5 ± 4.5%. No changes were observed in HRV indices after BTP, but after ITP, these indices increased significantly (HFP: 1.9%, P=0.026; TP: 1.7%, P=0.007). Significant correlations were observed between the change of Vpeak and HRV indices (TP: r=0.75, PHRV among recreational endurance runners, it seems that moderate- and high-intensity training are needed. This study showed that recreational endurance runners with a high HRV at baseline improved their endurance running performance after ITP more than runners with low baseline HRV. © 2011 John Wiley & Sons A/S.

  14. Functional and structural correlates of motor speed in the cerebellar anterior lobe.

    Directory of Open Access Journals (Sweden)

    Uwe Wenzel

    Full Text Available In athletics, motor performance is determined by different abilities such as technique, endurance, strength and speed. Based on animal studies, motor speed is thought to be encoded in the basal ganglia, sensorimotor cortex and the cerebellum. The question arises whether there is a unique structural feature in the human brain, which allows "power athletes" to perform a simple foot movement significantly faster than "endurance athletes". We acquired structural and functional brain imaging data from 32 track-and-field athletes. The study comprised of 16 "power athletes" requiring high speed foot movements (sprinters, jumpers, throwers and 16 endurance athletes (distance runners which in contrast do not require as high speed foot movements. Functional magnetic resonance imaging (fMRI was used to identify speed specific regions of interest in the brain during fast and slow foot movements. Anatomical MRI scans were performed to assess structural grey matter volume differences between athletes groups (voxel based morphometry. We tested maximum movement velocity of plantarflexion (PF-Vmax and acquired electromyographical activity of the lateral and medial gastrocnemius muscle. Behaviourally, a significant difference between the two groups of athletes was noted in PF-Vmax and fMRI indicates that fast plantarflexions are accompanied by increased activity in the cerebellar anterior lobe. The same region indicates increased grey matter volume for the power athletes compared to the endurance counterparts. Our results suggest that speed-specific neuro-functional and -structural differences exist between power and endurance athletes in the peripheral and central nervous system.

  15. Some physiological demands of a half-marathon race on recreational runners.

    Science.gov (United States)

    Williams, C; Nute, M L

    1983-09-01

    The purpose of this study was to assess the physiological demands of a half-marathon race on a group of ten recreational runners (8 men and 2 women). The average running speed was 223.1 +/- 22.7 m.min-1 (mean +/- SD) for the group and this represented 79 +/- 5% VO2 max for these runners. There was a good correlation between VO2 max and performance time for the race (4 = -0.81; p less than 0.01) and an even better correlation between running speed equivalent to a blood lactate concentration of 4 mmol.l-1 and performance times (r = -0.877; p less than 0.01). The blood lactate concentration os 4 of the runners at the end of the race was 5.65 +/- 1.42 mmol.l-1 (mean +/- SD) and the estimated energy expenditure for the group was 6.22 M.J. While there was only a poor correlation between total energy expenditure and performance time for the race, the correlation coefficient was improved when the energy expenditure of each individual was expressed in KJ.kg-1 min-1 (r = 0.938; p less than 0.01).

  16. Mixed maximal and explosive strength training in recreational endurance runners.

    Science.gov (United States)

    Taipale, Ritva S; Mikkola, Jussi; Salo, Tiina; Hokka, Laura; Vesterinen, Ville; Kraemer, William J; Nummela, Ari; Häkkinen, Keijo

    2014-03-01

    Supervised periodized mixed maximal and explosive strength training added to endurance training in recreational endurance runners was examined during an 8-week intervention preceded by an 8-week preparatory strength training period. Thirty-four subjects (21-45 years) were divided into experimental groups: men (M, n = 9), women (W, n = 9), and control groups: men (MC, n = 7), women (WC, n = 9). The experimental groups performed mixed maximal and explosive exercises, whereas control subjects performed circuit training with body weight. Endurance training included running at an intensity below lactate threshold. Strength, power, endurance performance characteristics, and hormones were monitored throughout the study. Significance was set at p ≤ 0.05. Increases were observed in both experimental groups that were more systematic than in the control groups in explosive strength (12 and 13% in men and women, respectively), muscle activation, maximal strength (6 and 13%), and peak running speed (14.9 ± 1.2 to 15.6 ± 1.2 and 12.9 ± 0.9 to 13.5 ± 0.8 km Ł h). The control groups showed significant improvements in maximal and explosive strength, but Speak increased only in MC. Submaximal running characteristics (blood lactate and heart rate) improved in all groups. Serum hormones fluctuated significantly in men (testosterone) and in women (thyroid stimulating hormone) but returned to baseline by the end of the study. Mixed strength training combined with endurance training may be more effective than circuit training in recreational endurance runners to benefit overall fitness that may be important for other adaptive processes and larger training loads associated with, e.g., marathon training.

  17. Ultra-obligatory running among ultramarathon runners.

    Science.gov (United States)

    Hoffman, Martin D; Krouse, Rhonna

    2018-01-01

    Participants in the Ultrarunners Longitudinal TRAcking (ULTRA) Study were asked to answer "yes" or "no" to the question "If you were to learn, with absolute certainty, that ultramarathon running is bad for your health, would you stop your ultramarathon training and participation?" Among the 1349 runners, 74.1% answered "no". Compared with those answering "yes", they were younger (p life meaning (p = 0.0002) scores on the Motivations of Marathoners Scales. Despite a high health orientation, most ultramarathon runners would not stop running if they learned it was bad for their health as it appears to serve their psychological and personal achievement motivations and their task orientation such that they must perceive enhanced benefits that are worth retaining at the risk of their health.

  18. Differences in Knee and Hip Adduction and Hip Muscle Activation in Runners With and Without Iliotibial Band Syndrome.

    Science.gov (United States)

    Baker, Robert L; Souza, Richard B; Rauh, Mitchell J; Fredericson, Michael; Rosenthal, Michael D

    2018-04-26

    Iliotibial band syndrome has been associated with altered hip and knee kinematics in runners. Previous studies have recommended further research on neuromuscular factors at the hip. The frontal plane hip muscles have been a strong focus in strength comparison but not for electromyography investigation. To compare hip surface electromyography, and frontal plane hip and knee kinematics, in runners with and without iliotibial band syndrome. Observational cross-sectional study. Thirty participants were tested for motion capture at the hip and knee and muscle activation in the lateral and posterior hip. Biomechanics research laboratory within a university. Thirty subjects were recruited consisting of 15 injured runners with iliotibial band syndrome and 15 gender-, age-, and body mass index-matched controls. In each group, 8 were male runners and 7 were female runners. Inclusion criteria for the injured group were pain within 2 months related to iliotibial band syndrome and a positive Noble compression test. Participants were excluded if they reported other lower extremity diagnoses within the last year or active lower extremity or low back pain not related to iliotibial band syndrome. Controls were excluded if they reported a history of iliotibial band syndrome. Convenience sampling was used based on referrals from local running clinics and orthopedic clinics. Three-dimensional motion capture was performed with 10 high-speed cameras synchronized with wireless surface electromyography during a 30-minute run. The first data point was at 3 minutes, using a constant speed of 2.74 meters per second. A second data point was at 30 minutes, using a self-selected pace by the participant to allow for a challenging run until completion at 30 minutes. Motion capture was reported as peak kinematic values from heel strike to peak knee flexion for hip adduction and knee adduction. Surface electromyography was reported as a percentage of maximal voluntary contraction for the gluteus

  19. Relationship between cytokines and running economy in marathon runners

    Directory of Open Access Journals (Sweden)

    Luna Junior Luiz Antonio

    2016-01-01

    Full Text Available Running economy (RE, expresses the relationship between the energy cost of running (Cr and the work performed by a runner and is an predictor of performance. Given the intense effort of marathon runners during training and competition and the dearth of studies that address performance and cytokines in this population, the objective of the current study was to investigate the relationship between RE and cytokines in marathon runners.

  20. Is changing footstrike pattern beneficial to runners?

    OpenAIRE

    Joseph Hamill; Allison H. Gruber

    2017-01-01

    Some researchers, running instructors, and coaches have suggested that the “optimal” footstrike pattern to improve performance and reduce running injuries is to land using a mid- or forefoot strike. Thus, it has been recommended that runners who use a rearfoot strike would benefit by changing their footstrike although there is little scientific evidence for suggesting such a change. The rearfoot strike is clearly more prevalent. The major reasons often given for changing to a mid- or forefoot...

  1. Cardiovascular Risks in Long Distance Runners.

    Science.gov (United States)

    Witham, Bethany Rolfe; Babbitt, Keven

    Distance running has become increasingly popular since the 1970s. Despite the health benefits, long-distance running has been associated with an increased risk for cardiac events. Healthcare professionals should be familiar with distance running cardiac risk factors and preparticipation screening recommendations from the American Heart Association, and should screen and educate patients during healthcare encounters. Nurses are particularly well suited to educate runners on risks and symptoms of cardiac dysfunction.

  2. Iron excess in recreational marathon runners.

    Science.gov (United States)

    Mettler, S; Zimmermann, M B

    2010-05-01

    Iron deficiency and anemia may impair athletic performance, and iron supplements are commonly consumed by athletes. However, iron overload should be avoided because of the possible long-term adverse health effects. We investigated the iron status of 170 male and female recreational runners participating in the Zürich marathon. Iron deficiency was defined either as a plasma ferritin (PF) concentration or =4.5 (functional iron deficiency). After excluding subjects with elevated C-reactive protein concentrations, iron overload was defined as PF >200 microg/l. Iron depletion was found in only 2 out of 127 men (1.6% of the male study population) and in 12 out of 43 (28.0%) women. Functional iron deficiency was found in 5 (3.9%) and 11 (25.5%) male and female athletes, respectively. Body iron stores, calculated from the sTfR/PF ratio, were significantly higher (Pmarathon runners. Median PF among males was 104 microg/l, and the upper limit of the PF distribution in males was 628 microg/l. Iron overload was found in 19 out of 127 (15.0%) men but only 2 out of 43 in women (4.7%). Gender (male sex), but not age, was a predictor of higher PF (Pperformance, our findings indicate excess body iron may be common in male recreational runners and suggest supplements should only be used if tests of iron status indicate deficiency.

  3. High-speed scanning ablation of dental hard tissues with a λ=9.3-μm CO2 laser: heat accumulation and peripheral thermal damage

    Science.gov (United States)

    Nguyen, Daniel; Staninec, Michal; Lee, Chulsung; Fried, Daniel

    2010-02-01

    A mechanically scanned CO2 laser operated at high laser pulse repetition rates can be used to rapidly and precisely remove dental decay. This study aims to determine whether these laser systems can safely ablate enamel and dentin without excessive heat accumulation and peripheral thermal damage. Peripheral thermal damage can adversely impact the mechanical strength of the irradiated tissue, particularly for dentin, and reduce the adhesion characteristics of the modified surfaces. Samples were derived from noncarious extracted molars. Pulpal temperatures were recorded using microthermocouples situated at the pulp chamber roof of samples (n=12), which were occlusally ablated using a rapid-scanning, water-cooled 300 Hz CO2 laser over a two minute time course. The mechanical strength of facially ablated dentin (n=10) was determined via four-point bend test and compared to control samples (n=10) prepared with 320 grit wet sand paper to simulate conventional preparations. Composite-to-enamel bond strength was measured via single-plane shear test for ablated/non-etched (n=10) and ablated/acid-etched (n=8) samples and compared to control samples (n=9) prepared by 320 grit wet sanding. Thermocouple measurements indicated that the temperature remained below ambient temperature at 19.0°C (s.d.=0.9) if water-cooling was used. There was no discoloration of either dentin and enamel, the treated surfaces were uniformly ablated and there were no cracks observable on the laser treated surfaces. Fourpoint bend tests yielded mean mechanical strengths of 18.2 N (s.d.=4.6) for ablated dentin and 18.1 N (s.d.=2.7) for control (p>0.05). Shear tests yielded mean bond strengths of 31.2 MPa (s.d.=2.5, penamel without excessive heat accumulation and with minimal thermal damage. It is not clear whether the small (16%) but statistically significant reduction in the shear bond strength to enamel is clinically significant since the mean shear bond strength exceeded 30 MPa.

  4. Prediction of maximal lactate steady state in runners with an incremental test on the field.

    Science.gov (United States)

    Leti, Thomas; Mendelson, Monique; Laplaud, David; Flore, Patrice

    2012-01-01

    During a maximal incremental ergocycle test, the power output associated with Respiratory Exchange Ratio equal to 1.00 (RER = 1.00) predicts maximal lactate steady state (MLSS). We hypothesised that these results are transferable for runners on the field. Fourteen runners performed a maximal progressive test, to assess the speed associated with RER = 1.00, and several 30 minutes constant velocity tests to determine the speed at MLSS. We observed that the speeds at RER = 1.00, at the second ventilatory threshold (VT2) and at MLSS did not differ (15.7 ± 1.1 km · h⁻¹, 16.2 ± 1.4 km · h⁻¹, 15.5 ± 1.1 km · h⁻¹ respectively). The speed associated with RER = 1.00 was better correlated with that at MLSS (r = 0.79; p = 0.0008) than that at VT2 (r = 0.73; p = 0.002). Neither the concentration of blood lactate nor the heart rate differed between the speed at RER = 1.00 and that at MLSS from the 10th and the 30th minute of the constant velocity test. Bland and Altman analysis showed a fair agreement between the speed at MLSS and that at RER (0.2 ± 1.4 km · h⁻¹). This study demonstrated that the speed associated with RER = 1.00 determined during maximal progressive track running allows a fair estimation of the speed associated with MLSS, markedly decreasing the burden of numerous invasive tests required to assess it.

  5. Experiences with environmentally adapted Kaplan runners; Erfarenheter med miljoeanpassade Kaplanloephjul

    Energy Technology Data Exchange (ETDEWEB)

    Ukonsaari; Jan

    2012-08-15

    This study concerns environmentally adapted Kaplan runners, which have no oil for lubricating the blade regulation mechanisms and bearings. The runners are water or air filled with self lubricated bearings. Recent design also includes regulation system pressure increase and servo motor placement below runner centre and environmentally adapted synthetic ester as hydraulic fluid. These together with power output increase and efficiency optimization are suspected sources of poor runner function. Of 37 runners 43 % have had some kind of problem and 30 % bearing or mechanism related ones. When the axial blade bearing problems are excluded the problems occurred at 16 %. Deeper look into the design of newer runners shows that only bronze based runner hubs is significantly more problem dense regarding regulation mechanisms (50 %). Hidden figures of increased runner regulation forces are suspected. All problems cannot be explained and the young machines limit the experiences. The working group's opinion and bring ups of historical and present examples during the work show evidence that the old oil filled runners function is far from perfect, nor the life length. The future is not with oil filled runner hubs. Main parts of the discovered problems have been solved and can be resolved by thorough design analysis. One future concern is what effects the recent design changes will cause due to increase demand for power output changes including the number of starts and stops. That is why the working group's recommendation is to put joint effort into material fatigue and in which a first step is to identify the real forces the runners are exposed to.

  6. Impact of Center-of-Mass Acceleration on the Performance of Ultramarathon Runners

    Directory of Open Access Journals (Sweden)

    Lin Shun-Ping

    2014-12-01

    Full Text Available Ultramarathon races are rapidly gaining popularity in several countries, raising interest for the improvement of training programs. The aim of this study was to use a triaxial accelerometer to compare the three-dimensional centerof- mass accelerations of two groups of ultramarathon runners with distinct performances during different running speeds and distances. Ten runners who participated in the 12-h Taipei International Ultramarathon Race underwent laboratory treadmill testing one month later. They were divided into an elite group (EG; n = 5 and a sub-elite group (SG; n = 5. The triaxial center-of-mass acceleration recorded during a level-surface progressive intensity running protocol (3, 6, 8, 9, 10, and 12 km/h; 5 min each was used for correlation analyses with running distance during the ultramarathon. The EG showed negative correlations between mediolateral (ML acceleration (r = −0.83 to −0.93, p < 0.05, and between anterior-posterior (AP acceleration and running distance (r = −0.8953 to −0.9653, p < 0.05, but not for vertical control of the center of mass. This study suggests that runners reduce stride length to minimize mediolateral sway and the effects of braking on the trunk; moreover, cadence must be increased to reduce braking effects and enhance impetus. Consequently, the competition level of ultramarathons can be elevated.

  7. Effect of Peer Influence on Exercise Behavior and Enjoyment in Recreational Runners.

    Science.gov (United States)

    Carnes, Andrew J; Petersen, Jennifer L; Barkley, Jacob E

    2016-02-01

    Fitness professionals and popular media sources often recommend exercising with a partner to increase exercise motivation, adherence, intensity, and/or duration. Although competition with peers has been shown to enhance maximal athletic performance, experimental research examining the impact of peer influence on submaximal exercise behavior in adults is limited. The purpose of this study was to determine the effects of the presence of familiar and unfamiliar peers, vs. running alone, on recreational runners' voluntary running duration, distance, intensity, liking (i.e., enjoyment), and ratings of perceived exertion (RPEs). Recreational runners (n = 12 males, n = 12 females) completed 3 experimental trials, each under a different social condition, in a randomized order. Each trial consisted of self-paced running for a duration voluntarily determined by the participant. The 3 social conditions were running alone, with a sex- and fitness-matched familiar peer, or with a sex- and fitness-matched unfamiliar peer. A wrist-worn global positioning system was used to record running duration, distance, and average speed. Liking and RPE were assessed at the end of each trial. Mixed model regression analysis showed no significant effects of social condition (p ≥ 0.40) for any of the dependent variables. The presence of a familiar or unfamiliar peer did not alter recreational runners' running behavior, liking, or perceived exertion during submaximal exercise. However, exercising with others may have other benefits (e.g., reduced attrition) not examined herein.

  8. The influence of training and mental skills preparation on injury incidence and performance in marathon runners.

    Science.gov (United States)

    Hamstra-Wright, Karrie L; Coumbe-Lilley, John E; Kim, Hajwa; McFarland, Jose A; Huxel Bliven, Kellie C

    2013-10-01

    There has been a considerable increase in the number of participants running marathons over the past several years. The 26.2-mile race requires physical and mental stamina to successfully complete it. However, studies have not investigated how running and mental skills preparation influence injury and performance. The purpose of our study was to describe the training and mental skills preparation of a typical group of runners as they began a marathon training program, assess the influence of training and mental skills preparation on injury incidence, and examine how training and mental skills preparation influence marathon performance. Healthy adults (N = 1,957) participating in an 18-week training program for a fall 2011 marathon were recruited for the study. One hundred twenty-five runners enrolled and received 4 surveys: pretraining, 6 weeks, 12 weeks, posttraining. The pretraining survey asked training and mental skills preparation questions. The 6- and 12-week surveys asked about injury incidence. The posttraining survey asked about injury incidence and marathon performance. Tempo runs during training preparation had a significant positive relationship to injury incidence in the 6-week survey (ρ[93] = 0.26, p = 0.01). The runners who reported incorporating tempo and interval runs, running more miles per week, and running more days per week in their training preparation ran significantly faster than did those reporting less tempo and interval runs, miles per week, and days per week (p ≤ 0.05). Mental skills preparation did not influence injury incidence or marathon performance. To prevent injury, and maximize performance, while marathon training, it is important that coaches and runners ensure that a solid foundation of running fitness and experience exists, followed by gradually building volume, and then strategically incorporating runs of various speeds and distances.

  9. Shin Splints 101: Explaining Shin Splints to Young Runners

    Science.gov (United States)

    Newlin, Dana; Smith, Darla S.

    2011-01-01

    Shin splints are a common but often confusing injury. Sources disagree on both the cause of the injury and the anatomical source of the pain. Some blame shin splints on foot pronation, footstrike pattern, or arch height. Regardless of what causes the condition, it affects many runners, beginning in some at a young age. Young runners often have…

  10. Acute renal failure in four Comrades Marathon runners ingesting the ...

    African Journals Online (AJOL)

    Objectives. To evaluate common factors associated with the development of acute renal failure (ARF) in Comrades Marathon runners. Methods. This was a retrospective case series of 4 runners hospitalised post-race with ARF in the 89 km 2010 Comrades Marathon. The outcome measures were incidence of analgesic use, ...

  11. Infectious episodes in runners before and after a roadrace.

    Science.gov (United States)

    Nieman, D C; Johanssen, L M; Lee, J W

    1989-09-01

    Various researchers have implied that regular and moderate exercise training may improve the ability of the immune system to protect the host from infection. In contrast, acute, maximal, and exhaustive exercise may have negative effects of the immune system. This study compared the incidence of infectious episodes in 273 runners during a two month training period prior to a 5 K, 10 K, or half-marathon race. In addition, the effect of the race experience on infectious episodes was studied. Twenty-five percent of the runners training more than 15 miles per week reported at least one infectious episode as compared with 34.3% of runners training less than 15 miles per week (p = 0.09). Only 6.8% of the runners preparing for the half-marathon race reported becoming sick with the flu versus 17.9% of the 5 K and 10 K runners (p = 0.067). During the week following the roadrace, runners did not report an increase in infectious episodes as compared to the week prior to the race. These trends suggest that runners with a more serious commitment to regular exercise may experience less infectious episodes than recreational runners because of both direct and indirect affects on immunosurveillance. In addition, the stressful race experience does not appear to increase risk of acquiring an acute respiratory infection.

  12. Development of a 5kw Francis Turbine Runner Using Computation ...

    African Journals Online (AJOL)

    A small scale Francis turbine runner for a turbine located at Awba dam in the University of Ibadan with designed head and flow rate of 6m and 0.244m3/s is designed. The basic design of the Francis turbine runner is completed based on basic fluid dynamics turbo machinery principles. A 2-D and 3-D steady state, ...

  13. Different Training Modalities Improve Energy Cost and Performance in Master Runners

    Directory of Open Access Journals (Sweden)

    Lorenzo Pugliese

    2018-01-01

    Full Text Available Purpose: The aim of this study was to compare the effects of continuous moderate-intensity and discontinuous high-intensity training on running performance in master runners.Methods: Thirty-four male master runners (47.2 ± 7.4 years were assigned to three different groups: continuous moderate-intensity training (CMIT, discontinuous high-intensity training (DHIT, and control group (CON. CMIT and DHIT performed 8-week of supervised training (3 session·wk−1; ~35 km·wk−1 while CON maintained their normal training habits (3–4 session·wk−1; ~50 km·wk−1. Peak oxygen consumption (V˙O2peak and peak running speed (vpeak during incremental treadmill exercise, gas exchange threshold (GET, speed at GET, energy cost of running (Cr, and 5-km performance were evaluated before and after training.Results: Following the training period, both CMIT and DHIT significantly reduced Cr (−4.4 and −4.9%, respectively, P < 0.05, increased speed at GET (3.4 and 5.7%, P < 0.05 and improved 5-km time-trial performance (3.1 and 2.2%, P < 0.05 whereas no differences were found for V˙O2peak and GET (as %V˙O2peak. After training, vpeak improved only for DHIT (6%, P < 0.05. No differences were found in any variable for CON.Conclusions: This study indicates that both CMIT and DHIT may positively affect running performance in middle-aged master runners. This improvement was achieved despite a significant reduction of the amount of weekly training volume.

  14. Runners with Patellofemoral Pain Exhibit Greater Peak Patella Cartilage Stress Compared to Pain-Free Runners.

    Science.gov (United States)

    Liao, Tzu-Chieh; Keyak, Joyce H; Powers, Christopher M

    2018-02-27

    The purpose of this study is to determine whether recreational runners with patellofemoral pain (PFP) exhibit greater peak patella cartilage stress compared to pain-free runners. A secondary purpose was to determine the kinematic and/or kinetic predictors of peak patella cartilage stress during running. Twenty-two female recreational runners participated (12 with PFP and 10 pain-free controls). Patella cartilage stress profiles were quantified using subject-specific finite element models simulating the maximum knee flexion angle during stance phase of running. Input parameters to the finite element model included subject-specific patellofemoral joint geometry, quadriceps muscle forces, and lower extremity kinematics in the frontal and transverse planes. Tibiofemoral joint kinematics and kinetics were quantified to determine the best predictor of stress using stepwise regression analysis. Compared to the pain-free runners, those with PFP exhibited greater peak hydrostatic pressure (PFP vs. control, 21.2 ± 5.6 MPa vs. 16.5 ± 4.6 MPa) and maximum shear stress (11.3 ± 4.6 MPa vs. 8.7 ± 2.3 MPa). Knee external rotation was the best predictor of peak hydrostatic pressure and peak maximum shear stress (38% and 25% of variances, respectively) followed by the knee extensor moment (21% and 25% of variances, respectively). Runners with PFP exhibit greater peak patella cartilage stress during running compared to pain-free individuals. The combination of knee external rotation and a high knee extensor moment best predicted elevated peak stress during running.

  15. Thoracic pain in a collegiate runner.

    Science.gov (United States)

    Austin, G P; Benesky, W T

    2002-08-01

    This case study describes the process of examination, re-examination, and intervention for a collegiate runner with mechanical thoracic pain preventing athletic participation and limiting daily function. Unimpaired function fully returned in less than 3 weeks with biweekly sessions to re-establish normal and painfree thoracic mechanics via postural hygiene, exercise, mobilization, and manipulation. The outcome of this case study supports the original hypothesis that the pattern of impairments was in fact responsible for the functional limitations and disability in this athlete. At the time of publication the athlete was without functional limitations and had fully returned to competitive sprinting for the university track team.

  16. DO GENERAL MEDICAL PRACTITIONERS EXAMINE INJURED RUNNERS?

    DEFF Research Database (Denmark)

    Videbæk, Solvej; Jensen, A V; Rasmussen, S

    2017-01-01

    BACKGROUND: General Medical Practitioners (GMP) in Denmark perform clinical examinations of patients with musculoskeletal pain. However, the prevalence proportion of examinations caused by running-related injuries remains unknown. PURPOSE: The primary purpose of the present study was to estimate...... the prevalence proportion of consultations in general medical practice caused by running-related injuries. The secondary purpose was to estimate the prevalence proportion of injured runners, who consult their GMP, that are referred to additional examinations or treatments. STUDY DESIGN: A survey-based study...

  17. Cost of enlarged operating zone for an existing Francis runner

    Science.gov (United States)

    Monette, Christine; Marmont, Hugues; Chamberland-Lauzon, Joël; Skagerstrand, Anders; Coutu, André; Carlevi, Jens

    2016-11-01

    Traditionally, hydro power plants have been operated close to best efficiency point, the more stable operating condition for which they have been designed. However, because of changes in the electricity market, many hydro power plants operators wish to operate their machines differently to fulfil those new market needs. New operating conditions can include whole range operation, many start/stops, extensive low load operation, synchronous condenser mode and power/frequency regulation. Many of these new operating conditions may impose more severe fatigue damage than the traditional base load operation close to best efficiency point. Under these conditions, the fatigue life of the runner may be significantly reduced and reparation or replacement cost might occur sooner than expected. In order to design reliable Francis runners for those new challenging operating scenarios, Andritz Hydro has developed various proprietary tools and design rules. These are used within Andritz Hydro to design mechanically robust Francis runners for the operating scenarios fulfilling customer's specifications. To estimate residual life under different operating scenarios of an existing runner designed years ago for best efficiency base load operation, Andritz Hydro's design rules and tools would necessarily lead to conservative results. While the geometry of a new runner can be modified to fulfil all conservative mechanical design rules, the predicted fatigue life of an existing runner under off-design operating conditions may appear rather short because of the conservative safety factor included in the calculations. The most precise and reliable way to calculate residual life of an existing runner under different operating scenarios is to perform a strain gauge measurement campaign on the runner. This paper presents the runner strain gage measurement campaign of a mid-head Francis turbine over all the operating conditions available during the test, the analysis of the measurement signals

  18. Prospective comparison of running injuries between shod and barefoot runners.

    Science.gov (United States)

    Altman, Allison R; Davis, Irene S

    2016-04-01

    Advocates of barefoot running suggest that it is more natural and may be a way to minimise injury risk. In contrast, opponents believe shoes are needed to adequately cushion and support the foot. However, to date, there have been no prospective studies of injury patterns in barefoot and shod runners. The purpose of this study was to compare the incidence and rate of injuries between shod and barefoot runners. A prospective survey was conducted over the course of a year among 201 (107 barefoot and 94 shod) adult runners. Information regarding injuries and mileage was logged monthly using a custom, web-based database program. The number of injured runners, number of injuries per runner and injury rates were compared between habitual barefoot and habitual shod runners. Both musculoskeletal and plantar surface injuries were assessed. Statistically fewer overall, diagnosed, musculoskeletal injuries/runner were noted in the barefoot group. However, injury rates were not statistically different between groups due to significantly less mileage run in the barefoot group. As expected, barefoot runners sustained a statistically greater number of injuries to the plantar surface of the foot. The descriptive analysis suggests a greater number of calf injuries, but lower number of knee and hip injuries in the barefoot group. Additionally barefoot runners reported less plantar fasciitis than the shod group. Barefoot running is associated with fewer overall musculoskeletal injuries/runner, but similar injury rates. A larger scale cohort is needed to more accurately assess differences in individual injuries between these two groups. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  19. Cardiac Output and Performance during a Marathon Race in Middle-Aged Recreational Runners

    OpenAIRE

    Billat, Véronique L.; Petot, Hélène; Landrain, Morgan; Meilland, Renaud; Koralsztein, Jean Pierre; Mille-Hamard, Laurence

    2012-01-01

    Purpose. Despite the increasing popularity of marathon running, there are no data on the responses of stroke volume (SV) and cardiac output (CO) to exercise in this context. We sought to establish whether marathon performance is associated with the ability to sustain high fractional use of maximal SV and CO (i.e, cardiac endurance) and/or CO, per meter (i.e., cardiac cost). Methods. We measured the SV, heart rate (HR), CO, and running speed of 14 recreational runners in an incremental, maxima...

  20. S-06: Effect of Increased Cadence on Neuromuscular Response and Lower Limb Kinematics in Middle Distance Runners

    Directory of Open Access Journals (Sweden)

    Amrinder Singh

    2017-03-01

    Full Text Available AIM: To examine the differences in the neuromuscular and kinematic response in middle distance runners when the step rate was increased to 5% and 10% respectively of the preferred step rate.MATERIALS AND METHODOLOGY: 80 middle distance runners (40 males and 40 females participated in the study. EMG of 8 muscles (rectus femoris, medial and lateral hamstrings, medial gastrocnemius, tibialis anterior, gluteus medius and maximus, kinematic changes at the lower limb joints during stance and swing phase of running, foot pressure readings and spatiotemporal gait pa-rameters were recorded as each participant ran at their preferred speed, 5% increase in preferred speed and 10% increase in their preferred speed while keeping the treadmill speed constant.RESULTS: Kinematic analysis showed an increased knee flexion angle at initial contact (p < 0.001 and decreased knee flexion angle during swing phase (p < 0.001, Ankle showed reduced dorsiflex-ion angle at initial contact (p<0.001 and the hip showed less peak flexion (p < 0.001 across step rate conditions.With an increase in step rate, a fore foot strike running pattern was seen. Muscle activity was signif-icantly increased during the late swing and pre-swing at 10% of the preferred speed (p<0.001, with less significant changes during 5% of the preferred speed. During loading response, significant de-crease in muscle activity (p<0.05 was found between 5% and 10% increase of preferred speed.CONCLUSION: Increased cadence showed increased muscle activation and a forefoot strike run-ning pattern. The kinematic changes documented along with the neuromuscular response across the step rate conditions could be beneficial to runners for rehabilitation and injury prevention.

  1. Sleep habits and strategies of ultramarathon runners

    Science.gov (United States)

    Martin, Tristan; Arnal, Pierrick J.; Hoffman, Martin D.; Millet, Guillaume Y.

    2018-01-01

    Among factors impacting performance during an ultramarathon, sleep is an underappreciated factor that has received little attention. The aims of this study were to characterize habitual sleep behaviors in ultramarathon runners and to examine strategies they use to manage sleep before and during ultramarathons. Responses from 636 participants to a questionnaire were considered. This population was found to sleep more on weekends and holidays (7–8 h to 8–9 h) than during weekdays (6–7 h to 7–8 h; p sleep disorders, with more women (38.9%) reporting sleep problems than men (22.0%; p sleep preceding an ultramarathon, with 54.7% trying to increase their opportunities for sleep. Only 21% of participants reported that they had a strategy to manage sleep during ultramarathons, with micronaps being the most common strategy specified. Sub-analyses from 221 responses indicated that sleep duration during an ultramarathon was correlated with finish time for races lasting 36–60 h (r = 0.48; p 60 h (r = 0.44; p sleep duration among ultramarathon runners was comparable to the general population and other athletic populations, yet they reported a lower prevalence of sleep disorders. Daytime sleepiness was among the lowest rates encountered in athletic populations, which may be related to the high percentage of nappers in our population. Sleep extension, by increasing sleep time at night and daytime napping, was the main sleep strategy to prepare for ultramarathons. PMID:29742118

  2. Failure analysis of a Francis turbine runner

    Energy Technology Data Exchange (ETDEWEB)

    Frunzaverde, D; Campian, V [Research Center in Hydraulics, Automation and Heat Transfer, ' Eftimie Murgu' University of Resita P-ta Traian Vuia 1-4, RO-320085, Resita (Romania); Muntean, S [Centre of Advanced Research in Engineering Sciences, Romanian Academy - Timisoara Branch Bv. Mihai Viteazu 24, RO-300223, Timisoara (Romania); Marginean, G [University of Applied Sciences Gelsenkirchen, Neidenburger Str. 10, 45877 Gelsenkirchen (Germany); Marsavina, L [Department of Strength, ' Politehnica' University of Timisoara, Bv. Mihai Viteazu 1, RO-300222, Timisoara (Romania); Terzi, R; Serban, V, E-mail: gabriela.marginean@fh-gelsenkirchen.d, E-mail: d.frunzaverde@uem.r [Ramnicu Valcea Subsidiary, S.C. Hidroelectrica S.A., Str. Decebal 11, RO-240255, Ramnicu Valcea (Romania)

    2010-08-15

    The variable demand on the energy market requires great flexibility in operating hydraulic turbines. Therefore, turbines are frequently operated over an extended range of regimes. Francis turbines operating at partial load present pressure fluctuations due to the vortex rope in the draft tube cone. This phenomenon generates strong vibrations and noise that may produce failures on the mechanical elements of the machine. This paper presents the failure analysis of a broken Francis turbine runner blade. The failure appeared some months after the welding repair work realized in situ on fatigue cracks initiated near to the trailing edge at the junction with the crown, where stress concentration occurs. In order to determine the causes that led to the fracture of the runner blade, the metallographic investigations on a sample obtained from the blade is carried out. The metallographic investigations included macroscopic and microscopic examinations, both performed with light and scanning electron microscopy, as well as EDX - analyses. These investigations led to the conclusion, that the cracking of the blade was caused by fatigue, initiated by the surface unevenness of the welding seam. The failure was accelerated by the hydrogen embrittlement of the filling material, which appeared as a consequence of improper welding conditions. In addition to the metallographic investigations, numerical computations with finite element analysis are performed in order to evaluate the deformation and stress distribution on blade.

  3. Failure analysis of a Francis turbine runner

    International Nuclear Information System (INIS)

    Frunzaverde, D; Campian, V; Muntean, S; Marginean, G; Marsavina, L; Terzi, R; Serban, V

    2010-01-01

    The variable demand on the energy market requires great flexibility in operating hydraulic turbines. Therefore, turbines are frequently operated over an extended range of regimes. Francis turbines operating at partial load present pressure fluctuations due to the vortex rope in the draft tube cone. This phenomenon generates strong vibrations and noise that may produce failures on the mechanical elements of the machine. This paper presents the failure analysis of a broken Francis turbine runner blade. The failure appeared some months after the welding repair work realized in situ on fatigue cracks initiated near to the trailing edge at the junction with the crown, where stress concentration occurs. In order to determine the causes that led to the fracture of the runner blade, the metallographic investigations on a sample obtained from the blade is carried out. The metallographic investigations included macroscopic and microscopic examinations, both performed with light and scanning electron microscopy, as well as EDX - analyses. These investigations led to the conclusion, that the cracking of the blade was caused by fatigue, initiated by the surface unevenness of the welding seam. The failure was accelerated by the hydrogen embrittlement of the filling material, which appeared as a consequence of improper welding conditions. In addition to the metallographic investigations, numerical computations with finite element analysis are performed in order to evaluate the deformation and stress distribution on blade.

  4. Dynamic stability of running: The effects of speed and leg amputations on the maximal Lyapunov exponent

    International Nuclear Information System (INIS)

    Look, Nicole; Arellano, Christopher J.; Grabowski, Alena M.; Kram, Rodger; McDermott, William J.; Bradley, Elizabeth

    2013-01-01

    In this paper, we study dynamic stability during running, focusing on the effects of speed, and the use of a leg prosthesis. We compute and compare the maximal Lyapunov exponents of kinematic time-series data from subjects with and without unilateral transtibial amputations running at a wide range of speeds. We find that the dynamics of the affected leg with the running-specific prosthesis are less stable than the dynamics of the unaffected leg and also less stable than the biological legs of the non-amputee runners. Surprisingly, we find that the center-of-mass dynamics of runners with two intact biological legs are slightly less stable than those of runners with amputations. Our results suggest that while leg asymmetries may be associated with instability, runners may compensate for this effect by increased control of their center-of-mass dynamics

  5. Prescribed and self-reported seasonal training of distance runners.

    Science.gov (United States)

    Hewson, D J; Hopkins, W G

    1995-12-01

    A survey of 123 distance-running coaches and their best runners was undertaken to describe prescribed seasonal training and its relationship to the performance and self-reported training of the runners. The runners were 43 females and 80 males, aged 24 +/- 8 years (mean +/- S.D.), training for events from 800 m to the marathon, with seasonal best paces of 86 +/- 6% of sex- and age-group world records. The coaches and runners completed a questionnaire on typical weekly volumes of interval and strength training, and typical weekly volumes and paces of moderate and hard continuous running, for build-up, pre-competition, competition and post-competition phases of a season. Prescribed training decreased in volume and increased in intensity from the build-up through to the competition phase, and had similarities with 'long slow distance' training. Coaches of the faster runners prescribed longer build-ups, greater volumes of moderate continuous running and slower relative paces of continuous running (r = 0.19-0.36, P training close to competition pace. The mean training volumes and paces prescribed by the coaches were similar to those reported by the runners, but the correlations between prescribed and reported training were poor (r = 0.2-0.6). Coaches may therefore need to monitor their runners' training more closely.

  6. Peripheral reactions

    International Nuclear Information System (INIS)

    Greiner, D.

    1978-01-01

    Peripheral collisions, that is, collisions involving a small amount of overlap of nuclear matter, are discussed including inclusive interactions, the magnitude of the peripheral cross section, fragmentation, a compilation of experiments and available data, limiting fragmentation, factorization, some models, fragment momentum distributions, and future research directions

  7. Dynamic behaviour of pump-turbine runner: From disk to prototype runner

    International Nuclear Information System (INIS)

    Huang, X X; Egusquiza, E; Valero, C; Presas, A

    2013-01-01

    In recent decades, in order to increase output power of hydroelectric turbomachinery, the design head and the flow rate of the hydraulic turbines have been increased greatly. This has led to serious vibratory problems. The pump-turbines have to work at various operation conditions to satisfy the requirements of the power grid. However, larger hydraulic forces will result in high vibration levels on the turbines, especially, when the machines operate at off-design conditions. Due to the economic considerations, the pump-turbines are built as light as possible, which will change the dynamic response of the structures. According to industrial cases, the fatigue damage of the pump-turbine runner induced by hydraulic dynamic forces usually happens on the outer edge of the crown, which is near the leading edges of blades. To better understand the reasons for this kind of fatigue, it is extremely important to investigate the dynamic response behaviour of the hydraulic turbine, especially the runner, by experimental measurement and numerical simulation. The pump-turbine runner has a similar dynamic response behaviour of the circular disk. Therefore, in this paper the dynamic response analyses for circular disks with different dimensions and disk-blades-disk structures were carried out to better understand the fundamental dynamic behaviour for the complex turbomachinery. The influences of the pattern and number of blades were discussed in detail

  8. Anthropometric and training variables related to half-marathon running performance in recreational female runners.

    Science.gov (United States)

    Knechtle, Beat; Knechtle, Patrizia; Barandun, Ursula; Rosemann, Thomas

    2011-05-01

    The relationship between skin-fold thickness and running has been investigated in distances ranging from 100 m to the marathon distance (42.195 km), with the exclusion of the half-marathon distance (21.0975 km). We investigated the association between anthropometric variables, prerace experience, and training variables with race time in 42 recreational, nonprofessional, female half-marathon runners using bi- and multivariate analysis. Body weight (r, 0.60); body mass index (r, 0.48); body fat percentage (r, 0.56); pectoral (r, 0.61), mid-axilla (r, 0.69), triceps (r, 0.49), subscapular (r, 0.61), abdominal (r, 0.59), suprailiac (r, 0.55), and medial calf (r, 0.53) skin-fold thickness; mean speed of the training sessions (r, -0.68); and personal best time in a half-marathon (r, 0.69) correlated with race time after bivariate analysis. Body weight (P = 0.0054), pectoral skin-fold thickness (P = 0.0068), and mean speed of the training sessions (P = 0.0041) remained significant after multivariate analysis. Mean running speed during training was related to mid-axilla (r, -0.31), subscapular (r, -0.38), abdominal (r, -0.44), and suprailiac (r, -0.41) skin-fold thickness, the sum of 8 skin-fold thicknesses (r, -0.36); and percent body fat (r, -0.31). It was determined that variables of both anthropometry and training were related to half-marathon race time, and that skin-fold thicknesses were associated with running speed during training. For practical applications, high running speed during training (as opposed to extensive training) may both reduce upper-body skin-fold thicknesses and improve race performance in recreational female half-marathon runners.

  9. No Change in Running Mechanics With Live High-Train Low Altitude Training in Elite Distance Runners.

    Science.gov (United States)

    Stickford, Abigail S L; Wilhite, Daniel P; Chapman, Robert F

    2017-01-01

    Investigations into ventilatory, metabolic, and hematological changes with altitude training have been completed; however, there is a lack of research exploring potential gait-kinematic changes after altitude training, despite a common complaint of athletes being a lack of leg "turnover" on return from altitude training. To determine if select kinematic variables changed in a group of elite distance runners after 4 wk of altitude training. Six elite male distance runners completed a 28-d altitude-training intervention in Flagstaff, AZ (2150 m), following a modified "live high-train low" model, wherein higherintensity runs were performed at lower altitudes (945-1150 m) and low-intensity sessions were completed at higher altitudes (1950-2850 m). Gait parameters were measured 2-9 d before departure to altitude and 1 to 2 d after returning to sea level at running speeds of 300-360 m/min. No differences were found in ground-contact time, swing time, or stride length or frequency after altitude training (P > .05). Running mechanics are not affected by chronic altitude training in elite distance runners. The data suggest that either chronic training at altitude truly has no effect on running mechanics or completing the live high-train low model of altitude training, where higher-velocity workouts are completed at lower elevations, mitigates any negative mechanical adaptations that may be associated with chronic training at slower speeds.

  10. Cardiac output and performance during a marathon race in middle-aged recreational runners.

    Science.gov (United States)

    Billat, Véronique L; Petot, Hélène; Landrain, Morgan; Meilland, Renaud; Koralsztein, Jean Pierre; Mille-Hamard, Laurence

    2012-01-01

    Despite the increasing popularity of marathon running, there are no data on the responses of stroke volume (SV) and cardiac output (CO) to exercise in this context. We sought to establish whether marathon performance is associated with the ability to sustain high fractional use of maximal SV and CO (i.e, cardiac endurance) and/or CO, per meter (i.e., cardiac cost). We measured the SV, heart rate (HR), CO, and running speed of 14 recreational runners in an incremental, maximal laboratory test and then during a real marathon race (mean performance: 3 hr 30 min ± 45 min). Our data revealed that HR, SV and CO were all in a high but submaximal steady state during the marathon (87.0 ± 1.6%, 77.2 ± 2.6%, and 68.7 ± 2.8% of maximal values, respectively). Marathon performance was inversely correlated with an upward drift in the CO/speed ratio (mL of CO × m(-1)) (r = -0.65, P marathon performance is inversely correlated with cardiac cost and positively correlated with cardiac endurance. The CO response could be a benchmark for race performance in recreational marathon runners.

  11. Do general medical practitioners examine injured runners?

    DEFF Research Database (Denmark)

    Andersen, Solvej Videbæk; Jensen, A V; Rasmussen, Sten

    2017-01-01

    BACKGROUND: General Medical Practitioners (GMP) in Denmark perform clinical examinations of patients with musculoskeletal pain. However, the prevalence proportion of examinations caused by running-related injuries remains unknown. PURPOSE: The primary purpose of the present study was to estimate...... the prevalence proportion of consultations in general medical practice caused by running-related injuries. The secondary purpose was to estimate the prevalence proportion of injured runners, who consult their GMP, that are referred to additional examinations or treatments. STUDY DESIGN: A survey-based study....... METHODS: An online survey was distributed in October and November 2015 to more than 370 GMPs in Denmark and completed by 27. RESULTS: The median prevalence proportion of consultations caused by running-related injuries in the prior two weeks was 0.80% [25th percentile = 0.00%; 75th percentile = 1...

  12. Experimental Pressure Measurements on Hydropower Turbine Runners

    Energy Technology Data Exchange (ETDEWEB)

    Harding, Samuel F.; Richmond, Marshall C.

    2017-04-28

    The range of hydrodynamic operating conditions to which the turbine is exposed results in significant pressure fluctuations on both the pressure and suction sides of the blades. Understanding these dynamic pressures has a range of applications. Structurally, the resulting dynamic loads are significant in understanding the design life and maintenance schedule of the bearing, shafts and runner components. The pulsing pressures have also been seen to have a detrimental effect on the surface condition of the blades. Biologically, the pressure gradients and pressure extremes are the primary driver of barotrauma for fish passing through hydroturbines. Improvements in computational fluid dynamics (CFD) can be used to simulate such unsteady pressures in the regions of concern. High frequency model scale and prototype measurements of pressures at the blade are important in the validation of these models. Experimental characterization of pressure fields over hydroturbine blades has been demonstrated by a number of studies which using multiple pressure transducers to map the pressure contours on the runner blades. These have been performed at both model and prototype scales, often to validate computational models of the pressure and flow fields over the blades. This report provides a review of existing studies in which the blade pressure was measured in situ. The report assesses the technology for both model and prototype scale testing. The details of the primary studies in this field are reported and used to inform the types of hardware required for similar experiments based on the Ice Harbor Dam owned by the US Corps of Engineers on the Snake River, WA, USA. Such a study would be used to validate the CFD performed for the BioPA.

  13. Higher Precision of Heart Rate Compared with VO2 to Predict Exercise Intensity in Endurance-Trained Runners.

    Science.gov (United States)

    Reis, Victor M; den Tillaar, Roland Van; Marques, Mario C

    2011-01-01

    The aim of the present study was to assess the precision of oxygen uptake with heart rate regression during track running in highly-trained runners. Twelve national and international level male long-distance road runners (age 30.7 ± 5.5 yrs, height 1.71 ± 0.04 m and mass 61.2 ± 5.8 kg) with a personal best on the half marathon of 62 min 37 s ± 1 min 22 s participated in the study. Each participant performed, in an all-weather synthetic track five, six min bouts at constant velocity with each bout at an increased running velocity. The starting velocity was 3.33 m·s(-1) with a 0.56 m·s(-1) increase on each subsequent bout. VO2 and heart rate were measured during the runs and blood lactate was assessed immediately after each run. Mean peak VO2 and mean peak heart rate were, respectively, 76.2 ± 9.7 mL·kg(-1)·min(-1) and 181 ± 13 beats·min(-1). The linearity of the regressions between heart rate, running velocity and VO2 were all very high (r > 0.99) with small standard errors of regression (i.e. Sy.x at the velocity associated with the 2 and 4 mmol·L(-1) lactate thresholds). The strong relationships between heart rate, running velocity and VO2 found in this study show that, in highly trained runners, it is possible to have heart rate as an accurate indicator of energy demand and of the running speed. Therefore, in this subject cohort it may be unnecessary to use VO2 to track changes in the subjects' running economy during training periods. Key pointsHeart rate is used in the control of exercise intensity in endurance sports.However, few studies have quantified the precision of its relationship with oxygen uptake in highly trained runners.We evaluated twelve elite half-marathon runners during track running at various intensities and established three regressions: oxygen uptake / heart rate; heart rate / running velocity and oxygen uptake / running velocity.The three regressions presented, respectively, imprecision of 4,2%, 2,75% and 4,5% at the velocity

  14. Oral Contraceptives and Bone Health in Female Runners

    National Research Council Canada - National Science Library

    Kelsey, Jennifer

    2000-01-01

    .... This study is a two-year randomized trial of the effects of oral contraceptives on bone mass and stress fracture incidence among 150 female competitive distance runners in the age range 18-25 years...

  15. Oral Contraceptives and Bone Health in Female Runners

    National Research Council Canada - National Science Library

    Kelsey, Jennifer

    1999-01-01

    .... This study is a two-year randomized trial of the effects of oral contraceptives on bone mass and stress fracture incidence among 150 female competitive cross country runners in the age range 18-25 years...

  16. The occurrence of injuries in recreational runners in Wroclaw

    Directory of Open Access Journals (Sweden)

    Kamil Michalik

    2017-04-01

    Full Text Available Introduction. Practicing sports activities e.g. running exposes individuals to physical injuries. Aim. Aim of the study was to determine the occurrence of injuries in runners training long running in Wrocław. The second aim was to investigate injury risk factors in runners. Materials and methods. In the study participated 255 subjects (157 man and 98 woman. The subjects were members in a running association WKB PIAST Wrocław, PRO-RUN Wrocław as well as non associated runners. In the study a diagnostic survey was used. Results. In this study 61% (n=156 of participants were injured, while 39% (n=100 trained without any injuries. Conclusions. The runners suffered from overloads in plantar fascia, cuff muscles and quadriceps muscles. The main injury factors were improper training loads and training surface.

  17. Bone geometry, strength, and muscle size in runners with a history of stress fracture.

    Science.gov (United States)

    Popp, Kristin L; Hughes, Julie M; Smock, Amanda J; Novotny, Susan A; Stovitz, Steven D; Koehler, Scott M; Petit, Moira A

    2009-12-01

    Our primary aim was to explore differences in estimates of tibial bone strength, in female runners with and without a history of stress fractures. Our secondary aim was to explore differences in bone geometry, volumetric density, and muscle size that may explain bone strength outcomes. A total of 39 competitive distance runners aged 18-35 yr, with (SFX, n = 19) or without (NSFX, n = 20) a history of stress fracture were recruited for this cross-sectional study. Peripheral quantitative computed tomography (XCT 3000; Orthometrix, White Plains, NY) was used to assess volumetric bone mineral density (vBMD, mg x mm(-3)), bone area (ToA, mm(2)), and estimated compressive bone strength (bone strength index (BSI) = ToA x total volumetric density (ToD(2))) at the distal tibia (4%). Total (ToA, mm(2)) and cortical (CoA, mm(2)) bone area, cortical vBMD, and estimated bending strength (strength-strain index (SSIp), mm(3)) were measured at the 15%, 25%, 33%, 45%, 50%, and 66% sites. Muscle cross-sectional area (MCSA) was measured at the 50% and 66% sites. Participants in the SFX group had significantly smaller (7%-8%) CoA at the 45%, 50%, and 66% sites (P stress fracture. However, the lower strength was appropriate for the smaller muscle size, suggesting that interventions to reduce stress fracture risk might be aimed at improving muscle size and strength.

  18. Performance assessment of a small wind turbine with crossflow runner by numerical simulations

    Energy Technology Data Exchange (ETDEWEB)

    Dragomirescu, A. [University Politehnica of Bucharest, Department of Hydraulics, Hydraulic Machinery and Environmental Engineering, Splaiul Independentei 313, 060042 Bucharest (Romania)

    2011-03-15

    Most of the classical wind turbines are not able to start at wind speeds as low as 2-3 m/s. Other turbines, like Savonius, have a low maximum efficiency, which renders them useless in poor wind conditions. Therefore, new turbine designs are required to harvest wind power even when the wind speed is low. A wind turbine having a crossflow runner, similar to the Banki water turbine, is studied numerically in this work in order to estimate its performance. The results obtained suggest that this turbine has a considerable high starting torque and its maximum power coefficient is comparable to those of horizontal axis wind turbines. Based on the results obtained, some improvements of the design are proposed in order to further increase turbine performance. (author)

  19. Optimal stride frequencies in running at different speeds.

    Directory of Open Access Journals (Sweden)

    Ben T van Oeveren

    Full Text Available During running at a constant speed, the optimal stride frequency (SF can be derived from the u-shaped relationship between SF and heart rate (HR. Changing SF towards the optimum of this relationship is beneficial for energy expenditure and may positively change biomechanics of running. In the current study, the effects of speed on the optimal SF and the nature of the u-shaped relation were empirically tested using Generalized Estimating Equations. To this end, HR was recorded from twelve healthy (4 males, 8 females inexperienced runners, who completed runs at three speeds. The three speeds were 90%, 100% and 110% of self-selected speed. A self-selected SF (SFself was determined for each of the speeds prior to the speed series. The speed series started with a free-chosen SF condition, followed by five imposed SF conditions (SFself, 70, 80, 90, 100 strides·min-1 assigned in random order. The conditions lasted 3 minutes with 2.5 minutes of walking in between. SFself increased significantly (p<0.05 with speed with averages of 77, 79, 80 strides·min-1 at 2.4, 2.6, 2.9 m·s-1, respectively. As expected, the relation between SF and HR could be described by a parabolic curve for all speeds. Speed did not significantly affect the curvature, nor did it affect optimal SF. We conclude that over the speed range tested, inexperienced runners may not need to adapt their SF to running speed. However, since SFself were lower than the SFopt of 83 strides·min-1, the runners could reduce HR by increasing their SFself.

  20. Is changing footstrike pattern beneficial to runners?

    Directory of Open Access Journals (Sweden)

    Joseph Hamill

    2017-06-01

    Full Text Available Some researchers, running instructors, and coaches have suggested that the “optimal” footstrike pattern to improve performance and reduce running injuries is to land using a mid- or forefoot strike. Thus, it has been recommended that runners who use a rearfoot strike would benefit by changing their footstrike although there is little scientific evidence for suggesting such a change. The rearfoot strike is clearly more prevalent. The major reasons often given for changing to a mid- or forefoot strike are (1 it is more economical; (2 there is a reduction in the impact peak and loading rate of the vertical component of the ground reaction force; and (3 there is a reduction in the risk of a running-related injuries. In this paper, we critique these 3 suggestions and provide alternate explanations that may provide contradictory evidence for altering one's footstrike pattern. We have concluded, based on examining the research literature, that changing to a mid- or forefoot strike does not improve running economy, does not eliminate an impact at the foot-ground contact, and does not reduce the risk of running-related injuries.

  1. Sulfur status in long distance runners

    International Nuclear Information System (INIS)

    Kovacs, L; Zamboni, C; Lourenço, T; Macedo, D

    2015-01-01

    In sports medicine, sulfur plays an important role and its deficiency can cause muscle injury affecting the performance of the athletes. However, its evaluation is unusual in conventional clinical practice. In this study the sulfur levels were determined in Brazilian amateur athlete's blood using Neutron Activation Analyses (NAA) technique. Twenty six male amateur runners, age 18 to 36 years, participated of this study. The athletes had a balanced diet, without multivitamin/mineral supplements. The blood collection was performed at LABEX (Laboratoriode Bioquimica do Exercicio, UNICAMP-SP) and the samples were irradiated for 300 seconds in a pneumatic station in the nuclear reactor (IEA-R1, 3-4.5MW, pool type) at IPEN/CNEN-SP. The results were compared with the control group (subjects of same age but not involved with physical activities) and showed that the sulfur concentration was 44% higher in amateurs athletes than control group. These data can be considered for preparation of balanced diet, as well as contributing for proposing new protocols of clinical evaluation. (paper)

  2. Sulfur status in long distance runners

    Science.gov (United States)

    Kovacs, L.; Zamboni, C.; Lourenço, T.; Macedo, D.

    2015-07-01

    In sports medicine, sulfur plays an important role and its deficiency can cause muscle injury affecting the performance of the athletes. However, its evaluation is unusual in conventional clinical practice. In this study the sulfur levels were determined in Brazilian amateur athlete's blood using Neutron Activation Analyses (NAA) technique. Twenty six male amateur runners, age 18 to 36 years, participated of this study. The athletes had a balanced diet, without multivitamin/mineral supplements. The blood collection was performed at LABEX (Laboratoriode Bioquimica do Exercicio, UNICAMP-SP) and the samples were irradiated for 300 seconds in a pneumatic station in the nuclear reactor (IEA-R1, 3-4.5MW, pool type) at IPEN/CNEN-SP. The results were compared with the control group (subjects of same age but not involved with physical activities) and showed that the sulfur concentration was 44% higher in amateurs athletes than control group. These data can be considered for preparation of balanced diet, as well as contributing for proposing new protocols of clinical evaluation.

  3. Endocrine Changes In Egyptian Female Olympic Runners

    International Nuclear Information System (INIS)

    Bayad, M.A.; Fahmy, N.M.

    2002-01-01

    Circulating levels of testosterone (T), free testosterone (FT), and rostenedione (A) estradial 17-B (E 2 ), dehydroepiandrosterone sulfate (DHEA-S), sex hormone binding globulin (SHBG), luteninzing hormone (LH) and cortisol (C) were estimated by RIA proccdures in the serum of two groups of athletic female runners. An eumenorrheic group (n=10), and an oligomenorrheic group (n=10), and in a healthy regularly menstruating group as control(n=20). The athletes were subjected to a stadardized Ergometer testing aiming at achieving maximal O 2 consumption. Blood samples were with drawn at rest and immediately after exercise in the eumenorrheic and oligomenorrheic groups. Samples from eumenorrheic athletes and control group were at midfollicular phase of the cycle; and randomly in the oligomenorrheicat athlets. Results revealed a state of hypercortisolism in resting eumenorrheic athletes in comparison with control, whereas the oligomenorrheic athletes showed a state of hypercortisolism, hyperandrogenism and hyperestrogenism. The estimated perameters showed remrakable significant increase after the bicycle Ergometer testing, with the exception of SHBG and DHEA-S in the athletic groups

  4. Running, Being, and Beijing—An Existential Exploration of a Runner Identity

    DEFF Research Database (Denmark)

    Ronkainen, Noora; Harrison, Marlen Elliot; Ryba, Tatiana

    2014-01-01

    In this research, we explore the negotiation of a conflicted runner identity in a Finnish runner's short-term migration to Beijing, China. We examine the historical and cultural construction of the runner identity and discuss the current discourses that constitute the modern runner subjectivities...... and migration studies as well as practical considerations for the use of autoethnography in psychological research and practice.......In this research, we explore the negotiation of a conflicted runner identity in a Finnish runner's short-term migration to Beijing, China. We examine the historical and cultural construction of the runner identity and discuss the current discourses that constitute the modern runner subjectivities....... From there, we continue with a Heideggerian existential-phenomenological analysis of the ‘boundary situation’ when the project of competitive running is challenged due to environmental and cultural barriers in the migration. Our empirical inquiry is based on the first author's autoethnographic account...

  5. Relationship between running speed and initial foot contact patterns.

    Science.gov (United States)

    Breine, Bastiaan; Malcolm, Philippe; Frederick, Edward C; De Clercq, Dirk

    2014-08-01

    This study assessed initial foot contact patterns (IFCP) in a large group of distance runners and the effect of speed on the IFCP. We determined the strike index to classify the runners in IFCP groups, at four speeds (3.2, 4.1, 5.1, and 6.2 m·s), by measuring center of pressure (COP) with a 2-m plantar pressure plate. Such a system allows a direct localization of the COP on the plantar footprint and has a low threshold value (2.7 N·cm), resulting in more accurate COP data at low ground reaction forces than when obtained from force plate. The IFCP distribution evolves from mostly initial rearfoot contact (IRFC) (82%) at 3.2 m·s to more anterior foot contacts with an approximately equal distribution of IRFC (46%) and initial midfoot or forefoot contact (54%) at 6.2 m·s. Approximately 44% of the IRFC runners showed atypical COP patterns with a fast anterior displacement of the COP along the lateral shoe margin. Apart from the different COP patterns, these atypical IRFC were also characterized by a significantly higher instantaneous vertical loading rate than the typical IRFC patterns. The IFCP distribution changes were due to intraindividual alterations in IFCP at higher speeds. That is, 45% of the runners made one or even two "transitions" toward a more anterior IFCP (and 3% shows some other type of transition between initial foot contact styles as speed increases). However, 52% of the runners remained with the same IFCP.

  6. Effects of dietary antioxidants on training and performance in female runners.

    Science.gov (United States)

    Braakhuis, Andrea J; Hopkins, Will G; Lowe, Tim E

    2014-01-01

    Exercise-induced oxidative stress is implicated in muscle damage and fatigue which has led athletes to embark on antioxidant supplementation regimes to negate these effects. This study investigated the intake of vitamin C (VC) (1 g), blackcurrant (BC) juice (15 mg VC, 300 mg anthocyanins) and placebo in isocaloric drink form on training progression, incremental running test and 5-km time-trial performance. Twenty-three trained female runners (age, 31 ± 8 y; mean ± SD) completed three blocks of high-intensity training for 3 wks and 3 days, separated by a washout (~3.7 wks). Changes in training and performance with each treatment were analysed with a mixed linear model, adjusting for performance at the beginning of each training block. Markers of oxidative status included protein carbonyl, malondialdehyde (in plasma and in vitro erythrocytes), ascorbic acid, uric acid and erythrocyte enzyme activity of superoxide dismutase, catalase and glutathione peroxidase were analysed. There was a likely harmful effect on mean running speed during training when taking VC (1.3%; 90% confidence limits ±1.3%). Effects of the two treatments relative to placebo on mean performance in the incremental test and time trial were unclear, but runners faster by 1 SD of peak speed demonstrated a possible improvement on peak running speed with BC juice (1.9%; ±2.5%). Following VC, certain oxidative markers were elevated: catalase at rest (23%; ±21%), protein carbonyls at rest (27%; ±38%) and superoxide dismutase post-exercise (8.3%; ±9.3%). In conclusion, athletes should be cautioned about taking VC chronically, however, BC may improve performance in the elite.

  7. Cardiac Output and Performance during a Marathon Race in Middle-Aged Recreational Runners

    Directory of Open Access Journals (Sweden)

    Véronique L. Billat

    2012-01-01

    Full Text Available Purpose. Despite the increasing popularity of marathon running, there are no data on the responses of stroke volume (SV and cardiac output (CO to exercise in this context. We sought to establish whether marathon performance is associated with the ability to sustain high fractional use of maximal SV and CO (i.e, cardiac endurance and/or CO, per meter (i.e., cardiac cost. Methods. We measured the SV, heart rate (HR, CO, and running speed of 14 recreational runners in an incremental, maximal laboratory test and then during a real marathon race (mean performance: 3 hr 30 min ± 45 min. Results. Our data revealed that HR, SV and CO were all in a high but submaximal steady state during the marathon (87.0 ± 1.6%, 77.2 ± 2.6%, and 68.7 ± 2.8% of maximal values, respectively. Marathon performance was inversely correlated with an upward drift in the CO/speed ratio (mL of CO×m−1 (r=−0.65, P<0.01 and positively correlated with the runner’s ability to complete the race at a high percentage of the speed at maximal SV (r=0.83, P<0.0002. Conclusion. Our results showed that marathon performance is inversely correlated with cardiac cost and positively correlated with cardiac endurance. The CO response could be a benchmark for race performance in recreational marathon runners.

  8. Kinematic and kinetic comparison of barefoot and shod running in mid/forefoot and rearfoot strike runners.

    Science.gov (United States)

    Thompson, M A; Lee, S S; Seegmiller, J; McGowan, C P

    2015-05-01

    Barefoot running has been associated with decreased stride length and switching from a rearfoot strike (RFS) pattern to a mid/forefoot strike (M/FFS) pattern. However, some individuals naturally contact the ground on their mid/forefoot, even when wearing cushioned running shoes. The purpose of this study was to determine if the mechanics of barefoot running by natural shod RFS runners differed from natural shod M/FFS runners. Twenty habitually shod runners (ten natural M/FFS and ten natural RFS) participated in this study. Three-dimensional motion analysis and ground reaction force data were captured as subjects ran at their preferred running speed in both barefoot and shod conditions. M/FFS experienced only a decrease in stride length when switching from shod to barefoot running. Whereas, when switching from shod to barefoot running, RFS individuals experienced a decrease in stride length, switched to a plantarflexed position at ground contact and saw reduced impact peak magnitudes. These results suggest that when barefoot, the RFS group ran similar to the M/FFS group running barefoot or shod. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Effects of Interval Training-Based Glycolytic Capacity on Physical Fitness in Recreational Long-Distance Runners

    Directory of Open Access Journals (Sweden)

    Zatoń Marek

    2015-06-01

    Full Text Available Purpose. The aim of this study was to investigate the influence of 8-week-long interval training (targeting glycolytic capacity on selected markers of physical fitness in amateur long-distance runners. Methods. The study involved 17 amateur long-distance runners randomly divided into an experimental (n = 8 and control (n = 9 group. The control group performed three or four continuous training sessions per week whereas the experimental group performed two interval running training sessions and one continuous running training session. A graded treadmill exercise test and the 12-min Cooper test were performed pre- and post-training. Results. O2max and the rate of recovery increased in the experimental group. Relative oxygen uptake, minute ventilation, and heart rate speed decreased in low- (6 km/h and medium-intensity (12 km/h running. Conclusions. Both training modalities showed similar results. However, the significant differences in training volume (4-8 min interval training vs. 40-150 min continuous training indicates that the modalities targeting glycolytic capacity may be more efficient for amateur runners prepare for long-distance events.

  10. Marathon performance in relation to body fat percentage and training indices in recreational male runners

    Directory of Open Access Journals (Sweden)

    Tanda G

    2013-05-01

    Full Text Available Giovanni Tanda,1 Beat Knechtle2,31DIME, Università degli Studi di Genova, Genova, Italy; 2Gesundheitszentrum St Gallen, St Gallen, Switzerland; 3Institute of General Practice and Health Services Research, University of Zurich, Zurich, SwitzerlandBackground: The purpose of this study was to investigate the effect of anthropometric characteristics and training indices on marathon race times in recreational male marathoners.Methods: Training and anthropometric characteristics were collected for a large cohort of recreational male runners (n = 126 participating in the Basel marathon in Switzerland between 2010 and 2011.Results: Among the parameters investigated, marathon performance time was found to be affected by mean running speed and the mean weekly distance run during the training period prior to the race and by body fat percentage. The effect of body fat percentage became significant as it exceeded a certain limiting value; for a relatively low body fat percentage, marathon performance time correlated only with training indices.Conclusion: Marathon race time may be predicted (r = 0.81 for recreational male runners by the following equation: marathon race time (minutes = 11.03 + 98.46 exp(−0.0053 mean weekly training distance [km/week] + 0.387 mean training pace (sec/km + 0.1 exp(0.23 body fat percentage [%]. The marathon race time results were valid over a range of 165–266 minutes.Keywords: endurance, exercise, anthropometry

  11. Marathon performance in relation to body fat percentage and training indices in recreational male runners.

    Science.gov (United States)

    Tanda, Giovanni; Knechtle, Beat

    2013-01-01

    The purpose of this study was to investigate the effect of anthropometric characteristics and training indices on marathon race times in recreational male marathoners. Training and anthropometric characteristics were collected for a large cohort of recreational male runners (n = 126) participating in the Basel marathon in Switzerland between 2010 and 2011. Among the parameters investigated, marathon performance time was found to be affected by mean running speed and the mean weekly distance run during the training period prior to the race and by body fat percentage. The effect of body fat percentage became significant as it exceeded a certain limiting value; for a relatively low body fat percentage, marathon performance time correlated only with training indices. Marathon race time may be predicted (r = 0.81) for recreational male runners by the following equation: marathon race time (minutes) = 11.03 + 98.46 exp(-0.0053 mean weekly training distance [km/week]) + 0.387 mean training pace (sec/km) + 0.1 exp(0.23 body fat percentage [%]). The marathon race time results were valid over a range of 165-266 minutes.

  12. Effectiveness of neuromuscular taping on pronated foot posture and walking plantar pressures in amateur runners.

    Science.gov (United States)

    Aguilar, María Bravo; Abián-Vicén, Javier; Halstead, Jill; Gijon-Nogueron, Gabriel

    2016-04-01

    To determine the effect kinesiotaping (KT) versus sham kinesiotaping (sham KT) in the repositioning of pronated feet after a short running. Prospective, randomised, double-blinded, using a repeated-measures design with no cross-over. 116 amateur runners were screened by assessing the post-run (45min duration) foot posture to identify pronated foot types (defined by Foot Posture Index [FPI] score of ≥6). Seventy-three runners met the inclusion criteria and were allocated into two treatment groups, KT (n=49) and sham KT (n=24). After applying either the KT or sham KT and completing 45min of running (mean speed of 12km/h), outcome measures were collected (FPI and walking Pedobarography). FPI was reduced in both groups, more so in the KT group (mean FPI between group difference=0.9, CI 0.1-1.9), with a score closer to neutral. There were statistically significant differences between KT and sham KT (p<.05 and p<.01) in pressure time integral, suggesting that sham KT had a greater effect. KT may be of some assistant to clinicians in correction of pronated foot posture in a short-term. There was no effect of KT, however on pressure variables at heel strike or toe-off following a short duration of running, the sham KT technique had a greater effect. Therapy, level 1b. Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  13. Sex Differences in Limb and Joint Stiffness in Recreational Runners

    Directory of Open Access Journals (Sweden)

    Sinclair Jonathan

    2015-09-01

    Full Text Available Purpose. Female runners are known to be at greater risk from chronic running injuries than age-matched males, although the exact mechanisms are often poorly understood. The aim of the current investigation was to determine if female recreational runners exhibit distinct limb and joint stiffness characteristics in relation to their male counterparts. Methods. Fourteen male and fourteen female runners ran over a force platform at 4.0 m · s-1. Lower limb kinematics were collected using an eight-camera optoelectric motion capture system operating at 250 Hz. Measures of limb and joint stiffness were calculated as a function of limb length and joint moments divided by the extent of limb and joint excursion. All stiffness and joint moment parameters were normalized to body mass. Sex differences in normalized limb and knee and ankle joint stiffness were examined statistically using independent samples t tests. Results. The results indicate that normalized limb (male = 0.18 ± 0.07, female = 0.37 ± 0.10 kN · kg · m-1 and knee stiffness (male = 5.59 ± 2.02, female = 7.34 ± 1.78 Nm · kg · rad-1 were significantly greater in female runners. Conclusions. On the basis that normalized knee and limb stiffness were shown to be significantly greater in female runners, the findings from the current investigation may provide further insight into the aetiology of the distinct injury patterns observed between sexes.

  14. Bone mass and geometry of the tibia and the radius of master sprinters, middle and long distance runners, race-walkers and sedentary control participants: a pQCT

    NARCIS (Netherlands)

    Wilks, D.C.; Winwood, K.; Gilliver, S.F.; Kwiet, A.; Chatfield, M; Michaelis, I.; Sun, L.W.; Ferretti, J.L.; Sargeant, A.J.; Felsenberg, D.; Rittweger, J.

    2009-01-01

    Mechanical loading is thought to be a determinant of bone mass and geometry. Both ground reaction forces and tibial strains increase with running speed. This study investigates the hypothesis that surrogates of bone strength in male and female master sprinters, middle and long distance runners and

  15. The Influence of Matching Populations on Kinematic and Kinetic Variables in Runners with Iliotibial Band Syndrome

    Science.gov (United States)

    Grau, Stefan; Maiwald, Christian; Krauss, Inga; Axmann, Detlef; Horstmann, Thomas

    2008-01-01

    The purpose of this study was to assess how participant matching influences biomechanical variables when comparing healthy runners and runners with iliotibial band syndrome (ITBS). We examined 52 healthy runners (CO) and 18 with ITBS, using three-dimensional kinematics and pressure distribution. The study population was matched in three ways and…

  16. Peripheral Quantitative Computed Tomography (pQCT), Broad Band Ultrasound Attenuation (BUA) and Speed of Sound (SOS) in a population of normal females aged from 8 to 20 years

    International Nuclear Information System (INIS)

    Bagni, B.; Corazzari, T.; Bagni, I.; Garuti, F.; Franceschetto, A.; Casolo, A.; Pansini, F.

    2002-01-01

    Aim: To evaluate, in a population of young healthy females aged from 8 to 20 years the bone mass peak (or density), the normal ranges versus age and menarche-age using two method: pQCT (peripheral Quantitative Computed Tomography) and ultrasound absorptiometry. Material and Methods: From 1998 to 2000 selective measurement of Bone Mineral Density (BMD) of trabecular bone at the ultradistal radius using pQCT, BUA (Broad Band Attenuation) and SOS ( Speed Of Sound) was carried out on 426 healthy females (aged from 8 to 20 years) in north Italy. BMD were measured using a single photon miniaturized tomographic scanner in the ultradistal radius, SOS and BUA were measured at the same time, using a water bath device obtaining parametric bidimensional images of BUA and SOS. The population studied refers to normal females free of bone metabolism alteration, in pre and post-pubertal status. Results: A normal range of BMD, BUA and SOS versus age and menarche age were established. A linear correlation was found between BUA and BMD measured with pQCT. SOS does not show any correlation with BMD. The pre-puberty and the post-puberty groups show statistically significant differences between SOS, BUA and BMD. We found the peak bone density (measured with pQCT) in the trabecular bone at the ultradistal radius at 15 years of age (mean menarche age of 10 years). The same position of the peak was found for BUA, for SOS the situation is not well defined. The analytical fitting of the data highlights a polynomial correlation of BMD vs. age, SOS vs. age, BUA vs. age. Conclusions: It appears that the sexual growth influences the position of peak bone density. The results obtained show a statistically significant correlation between BUA and BMD versus age, the menarche-age and the period of exposure of bone tissue to the oestrogen. After all, pQCT and ultrasound are useful techniques to evaluate bone density and structure also in a growing population. The results of this study shows the

  17. Echocardiographic left ventricular masses in distance runners and weight lifters

    Science.gov (United States)

    Longhurst, J. C.; Gonyea, W. J.; Mitchell, J. H.; Kelly, A. R.

    1980-01-01

    The relationships of different forms of exercise training to left ventricular mass and body mass are investigated by echocardiographic studies of weight lifters, long-distance runners, and comparatively sized untrained control subjects. Left ventricular mass determinations by the Penn convention reveal increased absolute left ventricular masses in long-distance runners and competitive weight lifters with respect to controls matched for age, body weight, and body surface area, and a significant correlation between ventricular mass and lean body mass. When normalized to lean body mass, the ventricular masses of distance runners are found to be significantly higher than those of the other groups, suggesting that dynamic training elevates left ventricular mass compared to static training and no training, while static training increases ventricular mass only to the extent that lean body mass is increased.

  18. Normative values of eccentric hip abduction strength in novice runners

    DEFF Research Database (Denmark)

    Ramskov, D; Pedersen, M B; Kastrup, K

    2014-01-01

    normative values of maximal eccentric hip abduction strength in novice runners. METHODS: Novice healthy runners (n = 831) were recruited through advertisements at a hospital and a university. Maximal eccentric hip abduction strength was measured with a hand-held dynamometer. The demographic variables...... was found, p values were identified using a regression equation adjusting for age and gender. Based on this, the equation to calculate normative values for relative eccentric hip abduction strength became: (1.600 + (age * -0.005) + (gender (1 = male / 0 = female) * 0.215) ± 1 or 2 * 0......PURPOSE: Low eccentric strength of the hip abductors, might increase the risk of patellofemoral pain syndrome and iliotibial band syndrome in runners. No normative values for maximal eccentric hip abduction strength have been established. Therefore the purpose of this study was to establish...

  19. Foot-strike haemolysis in an ultramarathon runner.

    Science.gov (United States)

    Fazal, Abid A; Whittemore, Mary S; DeGeorge, Katharine C

    2017-12-13

    This case report describes mild anaemia and intravascular haemolysis in an otherwise healthy 41-year-old ultramarathon runner. In long-distance endurance athletes, trace gastrointestinal bleeding and plasma volume expansion are recognised sources of mild anaemia, often found incidentally. However, repetitive forceful foot striking can lead to blood cell lysis in the feet, resulting in a mild macrocytic anaemia and intravascular haemolysis, as was demonstrated in the patient described herein. Mild anaemia in runners, often called 'runner's pseudoanaemia', is typically clinically insignificant and does not require intervention. However, an unexplained anaemia can cause undue worry for otherwise healthy patients and lead to costly further testing, providing an argument against routine testing with complete blood counts in healthy, asymptomatic patients. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  20. Haematological status in elite long-distance runners

    DEFF Research Database (Denmark)

    Suetta, C; Kanstrup, I L; Fogh-Andersen, N

    1996-01-01

    In 10 female and eight male Danish elite middle- and long-distance runners, haematological status, including blood volume, was examined. Haemoglobin, haematocrit and serum (s)-ferritin concentrations were all within the normal range. In both men and women, blood volume, plasma volume...... and erythrocyte volume were increased in relation to various reference values. However, the runners had a low body weight due to a reduced fat level, 9.5% (7.3-15.1%) fat for the women, 5.9% (5.0-8.8%) fat (median and ranges) for the men, measured by dual-energy X-ray absorptiometry (DEXA) scanning. When...... the runners' body weights were 'normalized' to a reference population (25% fat for women, 15% fat for men), only plasma volume remained increased in relation to body weight for the women, whereas all the volumes remained increased for the men. This confirms that endurance training induces a true increased...

  1. Sports drink consumption and dental erosion among amateur runners.

    Science.gov (United States)

    Antunes, Leonardo S; Veiga, Lais; Nery, Victor S; Nery, Caio C; Antunes, Lívia A

    2017-01-01

    This cross-sectional study assessed the prevalence and potential risk factors for dental erosion in amateur athletes at running events. After a sample calculation, 108 runners from the state of Rio de Janeiro, Brazil, were selected and examined for dental wear by a single trained and calibrated evaluator (kappa = 1.00). To identify risk factors, the runners were interviewed by using a standardized, semi-structured questionnaire. The average (SD) age of the runners was 34.2 (11.45), and the prevalence of dental erosion was 19.4%. Gastroesophageal reflux, running frequency per week, and time expended during competition were associated with dental erosion (P dental erosion was not significant (P > 0.05). In conclusion, dental erosion was not associated with use of isotonic drinks. However, frequency of exercise per week and gastroesophageal reflux were risk factors for dental erosion.

  2. Effects of Surface Inclination on the Vertical Loading Rates and Landing Pattern during the First Attempt of Barefoot Running in Habitual Shod Runners

    Science.gov (United States)

    An, W.; Rainbow, M. J.; Cheung, R. T. H.

    2015-01-01

    Barefoot running has been proposed to reduce vertical loading rates, which is a risk factor of running injuries. Most of the previous studies evaluated runners on level surfaces. This study examined the effect of surface inclination on vertical loading rates and landing pattern during the first attempt of barefoot running among habitual shod runners. Twenty habitual shod runners were asked to run on treadmill at 8.0 km/h at three inclination angles (0°; +10°; −10°) with and without their usual running shoes. Vertical average rate (VALR) and instantaneous loading rate (VILR) were obtained by established methods. Landing pattern was decided using high-speed camera. VALR and VILR in shod condition were significantly higher (p running, but not in barefoot condition (p > 0.382). There was no difference (p > 0.413) in the landing pattern among all surface inclinations. Only one runner demonstrated complete transition to non-heel strike landing in all slope conditions. Reducing heel strike ratio in barefoot running did not ensure a decrease in loading rates (p > 0.15). Conversely, non-heel strike landing, regardless of footwear condition, would result in a softer landing (p < 0.011). PMID:26258133

  3. Effects of Surface Inclination on the Vertical Loading Rates and Landing Pattern during the First Attempt of Barefoot Running in Habitual Shod Runners

    Directory of Open Access Journals (Sweden)

    W. An

    2015-01-01

    Full Text Available Barefoot running has been proposed to reduce vertical loading rates, which is a risk factor of running injuries. Most of the previous studies evaluated runners on level surfaces. This study examined the effect of surface inclination on vertical loading rates and landing pattern during the first attempt of barefoot running among habitual shod runners. Twenty habitual shod runners were asked to run on treadmill at 8.0 km/h at three inclination angles (0°; +10°; −10° with and without their usual running shoes. Vertical average rate (VALR and instantaneous loading rate (VILR were obtained by established methods. Landing pattern was decided using high-speed camera. VALR and VILR in shod condition were significantly higher (p0.382. There was no difference (p>0.413 in the landing pattern among all surface inclinations. Only one runner demonstrated complete transition to non-heel strike landing in all slope conditions. Reducing heel strike ratio in barefoot running did not ensure a decrease in loading rates (p>0.15. Conversely, non-heel strike landing, regardless of footwear condition, would result in a softer landing (p<0.011.

  4. Effects of Surface Inclination on the Vertical Loading Rates and Landing Pattern during the First Attempt of Barefoot Running in Habitual Shod Runners.

    Science.gov (United States)

    An, W; Rainbow, M J; Cheung, R T H

    2015-01-01

    Barefoot running has been proposed to reduce vertical loading rates, which is a risk factor of running injuries. Most of the previous studies evaluated runners on level surfaces. This study examined the effect of surface inclination on vertical loading rates and landing pattern during the first attempt of barefoot running among habitual shod runners. Twenty habitual shod runners were asked to run on treadmill at 8.0 km/h at three inclination angles (0°; +10°; -10°) with and without their usual running shoes. Vertical average rate (VALR) and instantaneous loading rate (VILR) were obtained by established methods. Landing pattern was decided using high-speed camera. VALR and VILR in shod condition were significantly higher (p running, but not in barefoot condition (p > 0.382). There was no difference (p > 0.413) in the landing pattern among all surface inclinations. Only one runner demonstrated complete transition to non-heel strike landing in all slope conditions. Reducing heel strike ratio in barefoot running did not ensure a decrease in loading rates (p > 0.15). Conversely, non-heel strike landing, regardless of footwear condition, would result in a softer landing (p < 0.011).

  5. Competition Nutrition Practices of Elite Ultramarathon Runners.

    Science.gov (United States)

    Stellingwerff, Trent

    2016-02-01

    Anecdotal claims have suggested that an increasing number of ultramarathoners purposely undertake chronic low-carbohydrate (CHO) ketogenic diets while training, and race with very low CHO intakes, as a way to maximize fat oxidation and improve performance. However, very little empirical evidence exists on specific fueling strategies that elite ultramarathoners undertake to maximize race performance. The study's purpose was to characterize race nutrition habits of elite ultramarathon runners. Three veteran male ultrarunners (M ± SD; age 35 ± 2 years; mass 59.5 ± 1.7 kg; 16.7 ± 2.5 hr 100-mi. best times) agreed to complete a competition- specific nutrition intake questionnaire for 100-mi. races. Verbal and visual instructions were used to instruct the athletes on portion sizes and confirm dietary intake. Throughout 2014, the athletes competed in 16 ultramarathons with a total of 8 wins, including the prestigious Western States Endurance Run 100-miler (14.9 hr). The average prerace breakfast contained 70 ± 16 g CHO, 29 ± 20 g protein, and 21 ± 8 g fat. Athletes consumed an average of 1,162 ± 250 g of CHO (71 ± 20g/hr), with minor fat and protein intakes, resulting in caloric intakes totaling 5,530 ± 1,673 kcals (333 ± 105 kcals/hr) with 93% of calories coming from commercial products. Athletes also reported consuming 912 ± 322 mg of caffeine and 6.9 ± 2.4 g of sodium. Despite having limited professional nutritional input into their fueling approaches, all athletes practiced fueling strategies that maximize CHO intake and are congruent with contemporary evidence-based recommendations.

  6. Dietary supplement usage and motivation in Brazilian road runners.

    Science.gov (United States)

    Salgado, José Vítor Vieira; Lollo, Pablo Christiano Barboza; Amaya-Farfan, Jaime; Chacon-Mikahil, Mara PatríciaTraina

    2014-01-01

    The consumption of dietary supplements is highest among athletes and it can represent potential a health risk for consumers. The aim of this study was to determine the prevalence of consumption of dietary supplements by road runners. We interviewed 817 volunteers from four road races in the Brazilian running calendar. The sample consisted of 671 male and 146 female runners with a mean age of 37.9 ± 12.4 years. Of the sample, 28.33% reported having used some type of dietary supplement. The main motivation for this consumption is to increase in stamina and improve performance. The probability of consuming dietary supplements increased 4.67 times when the runners were guided by coaches. The consumption of supplements was strongly correlated (r = 0.97) with weekly running distance, and also highly correlated (r = 0.86) with the number of years the sport had been practiced. The longer the runner had practiced the sport, the higher the training volume and the greater the intake of supplements. The five most frequently cited reasons for consumption were: energy enhancement (29.5%), performance improvement (17.1%), increased level of endurance (10.3%), nutrient replacement (11.1%), and avoidance of fatigue (10.3%). About 30% of the consumers declared more than one reason for taking dietary supplements. The most consumed supplements were: carbohydrates (52.17%), vitamins (28.70%), and proteins (13.48%). Supplement consumption by road runners in Brazil appeared to be guided by the energy boosting properties of the supplement, the influence of coaches, and the experience of the user. The amount of supplement intake seemed to be lower among road runners than for athletes of other sports. We recommend that coaches and nutritionists emphasise that a balanced diet can meet the needs of physically active people.

  7. Altered neuroendocrine regulation of gonadotropin secretion in women distance runners.

    Science.gov (United States)

    Veldhuis, J D; Evans, W S; Demers, L M; Thorner, M O; Wakat, D; Rogol, A D

    1985-09-01

    We tested the hypothesis that the neuroendocrine control of gonadotropin secretion is altered in certain women distance runners with secondary amenorrhea. To this end, we quantitated the frequency and amplitude of spontaneous pulsatile LH secretion during a 24-h interval in nine such women. The ability of the pituitary gland to release LH normally was assessed by administration of graded bolus doses of GnRH during the subsequent 8 h. Compared to normally menstruating women, six of nine amenorrheic distance runners had a distinct reduction in spontaneous LH pulse frequency, with one, three, six, five, four, or two pulses per 24 h (normal, 8-15 pulses/24 h). This reduction in LH pulse frequency occurred without any significant alterations in plasma concentrations of estradiol and free testosterone or 24-h integrated serum concentrations of LH, FSH, or PRL. Moreover, in long-distance runners, the capacity of the pituitary gland to release LH was normal or accentuated in response to exogenous pulses of GnRH. In the six women athletes with diminished spontaneous LH pulsatility, acute ovarian responsiveness also was normal, since serum estradiol concentrations increased normally in response to the GnRH-induced LH pulses. Although long-distance runners had significantly lower estimated percent body fat compared to control women, specific changes in pulsatile gonadotropin release did not correlate with degree of body leanness. In summary, certain long-distance runners with secondary amenorrhea or severe oligomenorrhea have unambiguously decreased spontaneous LH pulse frequency with intact pituitary responsiveness to GnRH. This neuroendocrine disturbance may be relevant to exercise-associated amenorrhea, since pulsatile LH release is a prerequisite for cyclic ovarian function. We speculate that such alterations in pulsatile LH release in exercising women reflect an adaptive response of the hypothalamic pulse generator controlling the intermittent GnRH signal to the

  8. Physiological and training characteristics of recreational marathon runners

    OpenAIRE

    Gordon, Dan; Wightman, Sarah; Basevitch, Itay; Johnstone, James; Espejo-Sanchez, Carolina; Beckford, Chelsea; Boal, Mariette; Scruton, Adrian; Ferrandino, Mike; Merzbach, Viviane

    2017-01-01

    Dan Gordon,1 Sarah Wightman,2 Itay Basevitch,1 James Johnstone,1 Carolina Espejo-Sanchez,1 Chelsea Beckford,1 Mariette Boal,1 Adrian Scruton,1 Mike Ferrandino,1 Viviane Merzbach1 1Cambridge Centre for Sport and Exercise Sciences, Anglia Ruskin University, 2The Flying Runner, Cambridge, UK Purpose: The aim of this study was to examine the physical and training characteristics of recreational marathon runners within finish time bandings (2.5–3 h, 3–3.5 h, 3...

  9. Maximal respiratory pressures and pulmonary function in male runners.

    OpenAIRE

    Cordain, L; Glisan, B J; Latin, R W; Tucker, A; Stager, J M

    1987-01-01

    To determine the effects of long term exercise on respiratory muscle strength, maximal inspiratory (Pl max) and expiratory (PE max) pressures, pulmonary volumes and capacities and anthropometric parameters were measured in a group of 101 male runners aged 16 to 58 years. The runners exhibited significantly (p less than 0.05) lower PE max (202 +/- 41 cm H2O and significantly greater residual lung volumes (RV) (2.08 +/- 0.49 L) than predicted values for normal subjects of similar height and age...

  10. Iliotibial band syndrome in runners: a systematic review.

    Science.gov (United States)

    van der Worp, Maarten P; van der Horst, Nick; de Wijer, Anton; Backx, Frank J G; Nijhuis-van der Sanden, Maria W G

    2012-11-01

    The popularity of running is still growing and, as participation increases, the incidence of running-related injuries will also rise. Iliotibial band syndrome (ITBS) is the most common injury of the lateral side of the knee in runners, with an incidence estimated to be between 5% and 14%. In order to facilitate the evidence-based management of ITBS in runners, more needs to be learned about the aetiology, diagnosis and treatment of this injury. This article provides a systematic review of the literature on the aetiology, diagnosis and treatment of ITBS in runners. The Cochrane Library, MEDLINE, EMBASE, CINAHL, Web of Science, and reference lists were searched for relevant articles. Systematic reviews, clinical trials or observational studies involving adult runners (>18 years) that focused on the aetiology, diagnosis and/or treatment of ITBS were included and articles not written in English, French, German or Dutch were excluded. Two reviewers independently screened search results, assessed methodological quality and extracted data. The sum of all positive ratings divided by the maximum score was the percentage quality score (QS). Only studies with a QS higher than 60% were included in the analysis. The following data were extracted: study design; number and characteristics of participants; diagnostic criteria for ITBS; exposure/treatment characteristics; analyses/outcome variables of the study; and setting and theoretical perspective on ITBS. The studies of the aetiology of ITBS in runners provide limited or conflicting evidence and it is not clear whether hip abductor weakness has a major role in ITBS. The kinetics and kinematics of the hip, knee and/or ankle/foot appear to be considerably different in runners with ITBS to those without. The biomechanical studies involved small samples, and data seem to have been influenced by sex, height and weight of participants. Although most studies monitored the management of ITBS using clinical tests, these tests have not

  11. Pre- and postmarathon training habits of nonelite runners

    Directory of Open Access Journals (Sweden)

    Angela M Voight

    2011-03-01

    Full Text Available Angela M Voight1, William O Roberts1, Scott Lunos2, Lisa S Chow31Department of Family Medicine and Community Health; 2Biostatistical Design and Analysis Center, Clinical and Translational Science Institute; 3Department of Medicine, Division of Diabetes, Endocrinology and Metabolism, University of Minnesota, Minneapolis, MN, USABackground: Despite the increasing popularity of marathons, little research has examined the training habits of nonelite marathon runners. Given that nonelite runners, particularly those with a competitive motive, have a higher risk for injury than experienced elite runners, it is important for physicians to understand the training program and features that might distinguish running performance and injury rates in this population.Hypothesis: We hypothesized that nonelite runners who qualify for the Boston Marathon (“qualifiers” would have higher running volumes, more running sessions per week, lower injury rates, and lower body mass index (BMI than nonqualifying runners.Study design: A cross-sectional Web-based survey of runners (convenience sample at 1 month (n = 50 and 6 months (n = 41 after participation in the 2008 Twin Cities Marathon (TCM that acquired data on anthropometric measures, demographic data, finishing time, premarathon/current training program, and self-reported injury.Results: Thirteen of 50 initial survey respondents were classified as a “qualifier” based on their finishing time. Mean BMI was significantly lower in the qualifiers at 1 month (22.0 versus 23.9 kg/m2, P = 0.0267 but not 6 months postmarathon. There were no significant differences in training volume (running frequency, run length, or cross-training volume or injury rates between qualifiers and nonqualifiers. Prior to the 2008 TCM, 54% of runners included cross-training in their exercise program, which increased significantly to 74% 1 month postmarathon (P = 0.0039 and 71% 6 months postmarathon (P = 0.0325. There was no association

  12. High-speed scanning ablation of dental hard tissues with a λ = 9.3 μm CO2 laser: adhesion, mechanical strength, heat accumulation, and peripheral thermal damage

    OpenAIRE

    Nguyen, Daniel; Chang, Kwang; Hedayatollahnajafi, Saba; Staninec, Michal; Chan, Kenneth; Lee, Robert; Fried, Daniel

    2011-01-01

    CO2 lasers can be operated at high laser pulse repetition rates for the rapid and precise removal of dental decay. Excessive heat accumulation and peripheral thermal damage is a concern when using high pulse repetition rates. Peripheral thermal damage can adversely impact the mechanical strength of the irradiated tissue, particularly for dentin, and reduce the adhesion characteristics of the modified surfaces. The interpulpal temperature rise was recorded using microthermocouples situated at ...

  13. Predictor variables for a half marathon race time in recreational male runners.

    Science.gov (United States)

    Rüst, Christoph Alexander; Knechtle, Beat; Knechtle, Patrizia; Barandun, Ursula; Lepers, Romuald; Rosemann, Thomas

    2011-01-01

    The aim of this study was to investigate predictor variables of anthropometry, training, and previous experience in order to predict a half marathon race time for future novice recreational male half marathoners. Eighty-four male finishers in the 'Half Marathon Basel' completed the race distance within (mean and standard deviation, SD) 103.9 (16.5) min, running at a speed of 12.7 (1.9) km/h. After multivariate analysis of the anthropometric characteristics, body mass index (r = 0.56), suprailiacal (r = 0.36) and medial calf skin fold (r = 0.53) were related to race time. For the variables of training and previous experience, speed in running of the training sessions (r = -0.54) were associated with race time. After multivariate analysis of both the significant anthropometric and training variables, body mass index (P = 0.0150) and speed in running during training (P = 0.0045) were related to race time. Race time in a half marathon might be partially predicted by the following equation (r(2) = 0.44): Race time (min) = 72.91 + 3.045 * (body mass index, kg/m(2)) -3.884 * (speed in running during training, km/h) for recreational male runners. To conclude, variables of both anthropometry and training were related to half marathon race time in recreational male half marathoners and cannot be reduced to one single predictor variable.

  14. Effect of resistance training regimens on treadmill running and neuromuscular performance in recreational endurance runners.

    Science.gov (United States)

    Mikkola, Jussi; Vesterinen, Ville; Taipale, Ritva; Capostagno, Benoit; Häkkinen, Keijo; Nummela, Ari

    2011-10-01

    The purpose of this study was to assess the effects of heavy resistance, explosive resistance, and muscle endurance training on neuromuscular, endurance, and high-intensity running performance in recreational endurance runners. Twenty-seven male runners were divided into one of three groups: heavy resistance, explosive resistance or muscle endurance training. After 6 weeks of preparatory training, the groups underwent an 8-week resistance training programme as a supplement to endurance training. Before and after the 8-week training period, maximal strength (one-repetition maximum), electromyographic activity of the leg extensors, countermovement jump height, maximal speed in the maximal anaerobic running test, maximal endurance performance, maximal oxygen uptake ([V·]O(₂max)), and running economy were assessed. Maximal strength improved in the heavy (P = 0.034, effect size ES = 0.38) and explosive resistance training groups (P = 0.003, ES = 0.67) with increases in leg muscle activation (heavy: P = 0.032, ES = 0.38; explosive: P = 0.002, ES = 0.77). Only the heavy resistance training group improved maximal running speed in the maximal anaerobic running test (P = 0.012, ES = 0.52) and jump height (P = 0.006, ES = 0.59). Maximal endurance running performance was improved in all groups (heavy: P = 0.005, ES = 0.56; explosive: P = 0.034, ES = 0.39; muscle endurance: P = 0.001, ES = 0.94), with small though not statistically significant improvements in [V·]O(₂max) (heavy: ES = 0.08; explosive: ES = 0.29; muscle endurance: ES = 0.65) and running economy (ES in all groups running endurance performance. However, both heavy and explosive strength training were beneficial in improving neuromuscular characteristics, and heavy resistance training in particular contributed to improvements in high-intensity running characteristics. Thus, endurance runners should include heavy resistance training in their training programmes to enhance endurance performance, such as

  15. Intensity related changes of running economy in recreational level distance runners.

    Science.gov (United States)

    Engeroff, Tobias; Bernardi, Andreas; Niederer, Daniel; Wilke, Jan; Vogt, Lutz; Banzer, Winfried

    2017-09-01

    Running economy (RE) is often described as a key demand of running performance. The variety of currently used assessment methods with different running intensities and outcomes restricts interindividual comparability of RE in recreational level runners. The purpose of this study was to compare the influence of RE, assessed as oxygen cost (OC) and caloric unit cost (CUC), on running speed at individual physiological thresholds. Eighteen recreational runners performed: 1) a graded exercise test to estimate first ventilatory threshold (VT1), respiratory compensation point (RCP) and maximal oxygen uptake (VO2max); 2) discontinuous RE assessment to determine relative OC in milliliters per kilogram per kilometer (mL/kg/km) and CUC in kilocalories per kilogram per kilometer (kcal/kg/km) at three different running intensities: VT1, RCP and at a third standardized reference point (TP) in between. OC (mL/kg/km; at VT1: 235.4±26.2; at TP: 227.8±23.4; at RCP: 224.9±21.9) and CUC (kcal/kg/km at VT1: 1.18±0.13; at TP: 1.14±0.12; at RCP: 1.13±0.11) decreased with increasing intensities (P≤0.01). Controlling for the influence of sex OC and CUC linearly correlated with running speed at RCP and VO2max (P≤0.01). RE, even assessed at low intensity, is strongly related to running performance in recreational athletes. Both calculation methods used (OC and CUC) are sensitive for monitoring intensity related changes of substrate utilization. RE values decreased with higher running intensity indicating an increase of anaerobic and subsequent decrease of aerobic substrate utilization.

  16. Bone strength estimates relative to vertical ground reaction force discriminates women runners with stress fracture history.

    Science.gov (United States)

    Popp, Kristin L; McDermott, William; Hughes, Julie M; Baxter, Stephanie A; Stovitz, Steven D; Petit, Moira A

    2017-01-01

    To determine differences in bone geometry, estimates of bone strength, muscle size and bone strength relative to load, in women runners with and without a history of stress fracture. We recruited 32 competitive distance runners aged 18-35, with (SFX, n=16) or without (NSFX, n=16) a history of stress fracture for this case-control study. Peripheral quantitative computed tomography (pQCT) was used to assess volumetric bone mineral density (vBMD, mg/mm 3 ), total (ToA) and cortical (CtA) bone areas (mm 2 ), and estimated compressive bone strength (bone strength index; BSI, mg/mm 4 ) at the distal tibia. ToA, CtA, cortical vBMD, and estimated strength (section modulus; Zp, mm 3 and strength strain index; SSIp, mm 3 ) were measured at six cortical sites along the tibia. Mean active peak vertical (pkZ) ground reaction forces (GRFs), assessed from a fatigue run on an instrumented treadmill, were used in conjunction with pQCT measurements to estimate bone strength relative to load (mm 2 /N∗kg -1 ) at all cortical sites. SSIp and Zp were 9-11% lower in the SFX group at mid-shaft of the tibia, while ToA and vBMD did not differ between groups at any measurement site. The SFX group had 11-17% lower bone strength relative to mean pkZ GRFs (phistory of stress fracture. Bone strength relative to load is also lower in this same region suggesting that strength deficits in the middle 1/3 of the tibia and altered gait biomechanics may predispose an individual to stress fracture. Copyright © 2016. Published by Elsevier Inc.

  17. Gonadotropin Pulsatllity in FemaIe Long Distance Runners

    Science.gov (United States)

    1986-10-24

    findings as well as her current knowledge of this area, she developed her own model of GnRH release. She believe that norepinephrine has a tonic...that . ,·. ~ only long distance runners and cross country skiers had trouble with their menstrual cycles. Similarly, Erdelyi (1976) found a higher

  18. Nutrient Intake by Ultramarathon Runners: Can They Meet Recommendations?

    NARCIS (Netherlands)

    Wardenaar, F.C.; Vries, de J.H.M.; Witkamp, R.F.; Mensink, M.R.

    2015-01-01

    Purpose: The objective of this study was to investigate whether ultramarathon runners were able to meet nutrition recommendations during a training period and on a competition day. Methods: In preparation for a 60 or 120 km ultramarathon covering a varied terrain, male and female ultramarathon

  19. Time Evolution of Sublingual Microcirculatory Changes in Recreational Marathon Runners

    Science.gov (United States)

    Arstikyte, Justina; Vaitkaitiene, Egle; Vaitkaitis, Dinas

    2017-01-01

    We aimed to evaluate changes in sublingual microcirculation induced by a marathon race. Thirteen healthy male controls and 13 male marathon runners volunteered for the study. We performed sublingual microcirculation, using a Cytocam-IDF device (Braedius Medical, Huizen, Netherlands), and systemic hemodynamic measurements four times: 24 hours prior to their participation in the Kaunas Marathon (distance: 41.2 km), directly after finishing the marathon, 24 hours after the marathon, and one week after the marathon. The marathon runners exhibited a higher functional capillary density (FCD) and total vascular density of small vessels at the first visit compared with the controls. Overall, we did not find any changes in sublingual microcirculation of the marathon runners at any of the other visits. However, in a subgroup of marathon runners with a decreased FCD compared to the subgroup with increased FCD, the subgroup with decreased FCD had shorter running time (190.37 ± 30.2 versus 221.80 ± 23.4 min, p = 0.045), ingested less fluids (907 ± 615 versus 1950 ± 488 mL, p = 0.007) during the race, and lost much more weight (−2.4 ± 1.3 versus −1.0 ± 0.8 kg, p = 0.041). Recreational marathon running is not associated with an alteration of sublingual microcirculation. However, faster running and dehydration may be crucial for further impairing microcirculation. PMID:28828386

  20. Iliotibial band syndrome in runners: a systematic review

    NARCIS (Netherlands)

    van der Worp, M.P.; van der Horst, N.; de Wijer, A.; Backx, F.J.; Nijhuis-Van der Sanden, M.W.G.

    2012-01-01

    BACKGROUND: The popularity of running is still growing and, as participation increases, the incidence of running-related injuries will also rise. Iliotibial band syndrome (ITBS) is the most common injury of the lateral side of the knee in runners, with an incidence estimated to be between 5% and

  1. Kinematic classification of iliotibial band syndrome in runners.

    Science.gov (United States)

    Grau, S; Krauss, I; Maiwald, C; Axmann, D; Horstmann, T; Best, R

    2011-04-01

    Several inconsistent causative biomechanical factors are considered to be crucial in the occurrence of iliotibial band syndrome (ITBS). The focus of this study was on assessing differences in the kinematic characteristics between healthy runners [control group (CO)] and runners with ITBS in order to recommend treatment strategies to deal with this injury. Three-dimensional kinematics of barefoot running was used in the biomechanical setup. Both groups were matched with respect to gender, height and weight. After determining drop outs, the final population comprised 36 subjects (26 male and 10 female): 18 CO and 18 ITBS (13 male and five female, each). Kinematic evaluations indicate less hip adduction and frontal range of motion at the hip joint in runners with ITBS. Furthermore, maximum hip flexion velocity and maximum knee flexion velocity were lower in runners with ITBS. Lack of joint coordination, expressed as earlier hip flexion and a tendency toward earlier knee flexion, was found to be another discriminating variable in subjects with ITBS compared with CO subjects. We assume that an increase in range of motion at the hip joint, stretching of the hip abductors, as well as stretching the hamstrings, calf muscles and hip flexors will help treat ITBS. © 2009 John Wiley & Sons A/S.

  2. Exploring Experience of Runners with Sports Tracking Technology

    NARCIS (Netherlands)

    Kuru, Armagan

    2016-01-01

    Running has been perceived as an easy way of becoming physically active. Over time, amateur runners start to use technology to keep track of their training and be aware of their improvement. In that sense, this article explores runners’ experience with activity tracking technology. After giving a

  3. Diet intake and endurance performance in Kenyan runners

    DEFF Research Database (Denmark)

    Christensen, Dirk Lund

    2004-01-01

    Training and competing at elite as well as sub-elite level requires an optimal functioning of the body. This review looks at the case of the Kenyan runners, who consume a relatively high-quality diet based on vegetable sources with maize and kidney beans as the staple foods. The diet is high in c...

  4. NSAID and other analgesic use by endurance runners during ...

    African Journals Online (AJOL)

    Background. An increasing popularity of ultra-endurance events coupled with excessive or inappropriate non-steroidal anti-inflammatory drug (NSAID) use during such events could pose considerable potential risks to runners' health. Objective. To evaluate the incidence of NSAID and other analgesic use in distance ...

  5. Development of a 5kw Francis Turbine Runner Using Computation ...

    African Journals Online (AJOL)

    First Lady

    energy obtained is known as hydro-electric power which is one of the cheapest forms ... Turgo) used for hydropower generation (Sabourin et al., 1996). The Awba ... Function of draft tube is to convert unused kinetic energy at the exit of runner.

  6. Time Evolution of Sublingual Microcirculatory Changes in Recreational Marathon Runners.

    Science.gov (United States)

    Pranskunas, Andrius; Arstikyte, Justina; Pranskuniene, Zivile; Bernatoniene, Jurga; Kiudulaite, Inga; Vaitkaitiene, Egle; Vaitkaitis, Dinas; Brazaitis, Marius

    2017-01-01

    We aimed to evaluate changes in sublingual microcirculation induced by a marathon race. Thirteen healthy male controls and 13 male marathon runners volunteered for the study. We performed sublingual microcirculation, using a Cytocam-IDF device (Braedius Medical, Huizen, Netherlands), and systemic hemodynamic measurements four times: 24 hours prior to their participation in the Kaunas Marathon (distance: 41.2 km), directly after finishing the marathon, 24 hours after the marathon, and one week after the marathon. The marathon runners exhibited a higher functional capillary density (FCD) and total vascular density of small vessels at the first visit compared with the controls. Overall, we did not find any changes in sublingual microcirculation of the marathon runners at any of the other visits. However, in a subgroup of marathon runners with a decreased FCD compared to the subgroup with increased FCD, the subgroup with decreased FCD had shorter running time (190.37 ± 30.2 versus 221.80 ± 23.4 min, p = 0.045), ingested less fluids (907 ± 615 versus 1950 ± 488 mL, p = 0.007) during the race, and lost much more weight (-2.4 ± 1.3 versus -1.0 ± 0.8 kg, p = 0.041). Recreational marathon running is not associated with an alteration of sublingual microcirculation. However, faster running and dehydration may be crucial for further impairing microcirculation.

  7. Time Evolution of Sublingual Microcirculatory Changes in Recreational Marathon Runners

    Directory of Open Access Journals (Sweden)

    Andrius Pranskunas

    2017-01-01

    Full Text Available We aimed to evaluate changes in sublingual microcirculation induced by a marathon race. Thirteen healthy male controls and 13 male marathon runners volunteered for the study. We performed sublingual microcirculation, using a Cytocam-IDF device (Braedius Medical, Huizen, Netherlands, and systemic hemodynamic measurements four times: 24 hours prior to their participation in the Kaunas Marathon (distance: 41.2 km, directly after finishing the marathon, 24 hours after the marathon, and one week after the marathon. The marathon runners exhibited a higher functional capillary density (FCD and total vascular density of small vessels at the first visit compared with the controls. Overall, we did not find any changes in sublingual microcirculation of the marathon runners at any of the other visits. However, in a subgroup of marathon runners with a decreased FCD compared to the subgroup with increased FCD, the subgroup with decreased FCD had shorter running time (190.37±30.2 versus 221.80±23.4 min, p=0.045, ingested less fluids (907±615 versus 1950±488 mL, p=0.007 during the race, and lost much more weight (-2.4±1.3 versus -1.0±0.8 kg, p=0.041. Recreational marathon running is not associated with an alteration of sublingual microcirculation. However, faster running and dehydration may be crucial for further impairing microcirculation.

  8. Using Augmented Feedback to Decrease Patellofemoral Pain in Runners: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Lauren M. Cornwell

    2016-05-01

    Full Text Available Objective: Patellofemoral pain (PFP is a common injury in running. The cause of patellofemoral pain is multifactorial in nature, which results varied treatment approaches for this disorder. Many studies have examined the effect of using strengthening protocols targeted at subjects’ hip and quadriceps strength. Although these studies have resulted in a reduction in short-term PFP for runners, many continue to experience PFP after undergoing these treatment strategies. A more recent theory regarding the treatment of PFP in runners involves the use of augmented verbal and visual feedback. This treatment strategy involves giving the runner scheduled visual feedback to adapt their running strategies in hopes of reducing their PFP. Much of this research has been done with experienced runners in the age range of 18-22 years old. The purpose of this study was to examine the effects of augmented verbal and real-time visual feedback on patellofemoral pain. The hypothesis was that training with the use of auditory and visual feedback would improve patellofemoral pain in this runner. In clinical practice, auditory and visual feedback to change hip and knee mechanics while running may be used as a treatment strategy for patellofemoral pain. Design and Setting: The study was conducted in a controlled laboratory setting and was an experimental design including a single-subject. Participants: The subject was a recreational female runner that was 22 years of age. The subject was recruited via a flyer distributed on campus. Once the individual agreed to participate, they were given a date to begin the study. This study was approved by the Institutional Review Board at the institution. When the subject arrived at the first meeting, the informed consent was reviewed and signed by the subject. Intervention: At the first visit, the subject was given a PFP questionnaire to determine if they were eligible for the study. For this study, the subject was classified as

  9. Serum creatine kinase elevations in ultramarathon runners at high altitude.

    Science.gov (United States)

    Magrini, Danielle; Khodaee, Morteza; San-Millán, Iñigo; Hew-Butler, Tamara; Provance, Aaron J

    2017-05-01

    Creatine kinase (CK) is a sensitive enzyme marker for muscle damage in athletes. Elevated CK levels have been reported in many endurance physical activities. The consequence and possible long-term sequela of the CK elevation in athletes is unknown. There is a paucity of literature stating actual numerical values of CK associated with competing in an ultramarathon with extreme environmental conditions. Our hypothesis was that the serum CK levels increase significantly as a result of running a 161 km ultramarathon at high altitude. This was a prospective observational study of participants of the Leadville 100 ultramarathon race in Leadville, Colorado at high altitude (2800-3840 m) in August 2014. We collected blood samples from sixty-four volunteer runners before and eighty-three runners immediately after the race. Out of 669 athletes who started the race, 352 successfully completed the race in less than the 30-hour cut-off time (52%). The majority of runners were male (84%). We were able to collect both pre- and post-race blood samples from 36 runners. Out of these 36 runners, the mean pre-race CK was increased from 126 ± 64 U/L to 14,569 ± 14,729 U/L (p athletes' age, BMI, or finishing time. Significant elevation of CK level occurs as a result of running ultramarathons. The majority of athletes with significantly elevated CK levels were asymptomatic and required no major medical attention.

  10. Genetic aspects of athletic performance: the African runners phenomenon

    Directory of Open Access Journals (Sweden)

    Vancini RL

    2014-05-01

    Full Text Available Rodrigo Luiz Vancini,1 João Bosco Pesquero,2 Rafael Júlio Fachina,3,4 Marília dos Santos Andrade,1 João Paulo Borin,3 Paulo César Montagner,3 Claudio Andre Barbosa de Lira51Centro de Educação Física e Desportos, Universidade Federal do Espírito Santo, Vitória, Espírito Santo, Brazil; 2Departamento de Biofísica, Universidade Federal de São Paulo, São Paulo, Brazil; 3Departamento de Ciência do Esporte, Faculdade de Educação Física, Universidade Estadual de Campinas, Campinas, Brazil; 4Confederação Brasileira de Basquetebol, Rio de Janeiro, Brazil; 5Setor de Fisiologia Humana e do Exercício, Faculdade de Educação Física, Universidade Federal de Goiás, Goiânia, BrazilAbstract: The current dominance of African runners in long-distance running is an intriguing phenomenon that highlights the close relationship between genetics and physical performance. Many factors in the interesting interaction between genotype and phenotype (eg, high cardiorespiratory fitness, higher hemoglobin concentration, good metabolic efficiency, muscle fiber composition, enzyme profile, diet, altitude training, and psychological aspects have been proposed in the attempt to explain the extraordinary success of these runners. Increasing evidence shows that genetics may be a determining factor in physical and athletic performance. But, could this also be true for African long-distance runners? Based on this question, this brief review proposed the role of genetic factors (mitochondrial deoxyribonucleic acid, the Y chromosome, and the angiotensin-converting enzyme and the alpha-actinin-3 genes in the amazing athletic performance observed in African runners, especially the Kenyans and Ethiopians, despite their environmental constraints.Keywords: genes, genotype, physical exercise, endurance runners

  11. Bone stress in runners with tibial stress fracture.

    Science.gov (United States)

    Meardon, Stacey A; Willson, John D; Gries, Samantha R; Kernozek, Thomas W; Derrick, Timothy R

    2015-11-01

    Combinations of smaller bone geometry and greater applied loads may contribute to tibial stress fracture. We examined tibial bone stress, accounting for geometry and applied loads, in runners with stress fracture. 23 runners with a history of tibial stress fracture & 23 matched controls ran over a force platform while 3-D kinematic and kinetic data were collected. An elliptical model of the distal 1/3 tibia cross section was used to estimate stress at 4 locations (anterior, posterior, medial and lateral). Inner and outer radii for the model were obtained from 2 planar x-ray images. Bone stress differences were assessed using two-factor ANOVA (α=0.05). Key contributors to observed stress differences between groups were examined using stepwise regression. Runners with tibial stress fracture experienced greater anterior tension and posterior compression at the distal tibia. Location, but not group, differences in shear stress were observed. Stepwise regression revealed that anterior-posterior outer diameter of the tibia and the sagittal plane bending moment explained >80% of the variance in anterior and posterior bone stress. Runners with tibial stress fracture displayed greater stress anteriorly and posteriorly at the distal tibia. Elevated tibial stress was associated with smaller bone geometry and greater bending moments about the medial-lateral axis of the tibia. Future research needs to identify key running mechanics associated with the sagittal plane bending moment at the distal tibia as well as to identify ways to improve bone geometry in runners in order to better guide preventative and rehabilitative efforts. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. A comparative biomechanical analysis of habitually unshod and shod runners based on a foot morphological difference.

    Science.gov (United States)

    Mei, Qichang; Fernandez, Justin; Fu, Weijie; Feng, Neng; Gu, Yaodong

    2015-08-01

    Running is one of the most accessible physical activities and running with and without footwear has attracted extensive attention in the past several years. In this study 18 habitually male unshod runners and 20 habitually male shod runners (all with dominant right feet) participated in a running test. A Vicon motion analysis system was used to capture the kinematics of each participant's lower limb. The in-shoe plantar pressure measurement system was employed to measure the pressure and force exerted on the pressure sensors of the insole. The function of a separate hallux in unshod runners is analyzed through the comparison of plantar pressure parameters. Owing to the different strike patterns in shod and unshod runners, peak dorsiflexion and plantarflexion angle were significantly different. Habitually shod runners exhibited a decreased foot strike angle (FSA) under unshod conditions; and the vertical average loading rate (VALR) of shod runners under unshod conditions was larger than that under shod conditions. This suggests that the foot strike pattern is more important than the shod or unshod running style and runners need to acquire the technique. It can be concluded that for habitually unshod runners the separate hallux takes part of the foot loading and reduces loading to the forefoot under shod conditions. The remaining toes of rearfoot strike (RFS) runners function similarly under unshod conditions. These morphological features of shod and unshod runners should be considered in footwear design to improve sport performance and reduce injury. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Incidence of chronic knee lesions in long-distance runners based on training level: Findings at MRI

    International Nuclear Information System (INIS)

    Schueller-Weidekamm, Claudia; Schueller, Gerd; Uffmann, Martin; Bader, Till

    2006-01-01

    Purpose: The purpose of this study was to evaluate the incidence of chronic knee changes in long-distance runners based on the training status, including distance, running frequency, training pace, and running experience. Methods: MRI of the knee was performed in 26 non-professional runners 5 days after their last training unit. Lesions of the menisci and cartilage (5-point scale), bone marrow and ligaments (3-point scale), and joint effusion were evaluated. A total score comprising all knee lesions in each runner was evaluated. The incidence of the knee changes was correlated with the training level, gender, and age of the runners. Results: Grade 1 lesions of the menisci were found in six runners with a high training level, and in only four runners with a low training level. Grade 1 cartilage lesions were found in three high-trained runners and in one low-trained runner, and grade 2 lesions were found in one high-trained runner and in two low-trained runners, respectively. Grade 1 anterior cruciate ligament lesions were seen in three runners with a high- and in two runners with a low-training level. Runners with a higher training level showed a statistically significant higher score for all chronic knee lesions than those with a lower training level (p < 0.05). Conclusions: MRI findings indicate that a higher training level in long-distance runners is a risk factor for chronic knee lesions

  14. Incidence of chronic knee lesions in long-distance runners based on training level: Findings at MRI

    Energy Technology Data Exchange (ETDEWEB)

    Schueller-Weidekamm, Claudia [Department of Radiology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria)]. E-mail: claudia.schueller-weidekamm@meduniwien.ac.at; Schueller, Gerd [Department of Radiology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Uffmann, Martin [Department of Radiology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria); Bader, Till [Department of Radiology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna (Austria)

    2006-05-15

    Purpose: The purpose of this study was to evaluate the incidence of chronic knee changes in long-distance runners based on the training status, including distance, running frequency, training pace, and running experience. Methods: MRI of the knee was performed in 26 non-professional runners 5 days after their last training unit. Lesions of the menisci and cartilage (5-point scale), bone marrow and ligaments (3-point scale), and joint effusion were evaluated. A total score comprising all knee lesions in each runner was evaluated. The incidence of the knee changes was correlated with the training level, gender, and age of the runners. Results: Grade 1 lesions of the menisci were found in six runners with a high training level, and in only four runners with a low training level. Grade 1 cartilage lesions were found in three high-trained runners and in one low-trained runner, and grade 2 lesions were found in one high-trained runner and in two low-trained runners, respectively. Grade 1 anterior cruciate ligament lesions were seen in three runners with a high- and in two runners with a low-training level. Runners with a higher training level showed a statistically significant higher score for all chronic knee lesions than those with a lower training level (p < 0.05). Conclusions: MRI findings indicate that a higher training level in long-distance runners is a risk factor for chronic knee lesions.

  15. Numerical Simulation of the Francis Turbine and CAD used to Optimized the Runner Design (2nd).

    Science.gov (United States)

    Sutikno, Priyono

    2010-06-01

    Hydro Power is the most important renewable energy source on earth. The water is free of charge and with the generation of electric energy in a Hydroelectric Power station the production of green house gases (mainly CO2) is negligible. Hydro Power Generation Stations are long term installations and can be used for 50 years and more, care must be taken to guarantee a smooth and safe operation over the years. Maintenance is necessary and critical parts of the machines have to be replaced if necessary. Within modern engineering the numerical flow simulation plays an important role in order to optimize the hydraulic turbine in conjunction with connected components of the plant. Especially for rehabilitation and upgrading existing Power Plants important point of concern are to predict the power output of turbine, to achieve maximum hydraulic efficiency, to avoid or to minimize cavitations, to avoid or to minimized vibrations in whole range operation. Flow simulation can help to solve operational problems and to optimize the turbo machinery for hydro electric generating stations or their component through, intuitive optimization, mathematical optimization, parametric design, the reduction of cavitations through design, prediction of draft tube vortex, trouble shooting by using the simulation. The classic design through graphic-analytical method is cumbersome and can't give in evidence the positive or negative aspects of the designing options. So it was obvious to have imposed as necessity the classical design methods to an adequate design method using the CAD software. There are many option chose during design calculus in a specific step of designing may be verified in ensemble and detail form a point of view. The final graphic post processing would be realized only for the optimal solution, through a 3 D representation of the runner as a whole for the final approval geometric shape. In this article it was investigated the redesign of the hydraulic turbine's runner

  16. Surrogate runner model for draft tube losses computation within a wide range of operating points

    International Nuclear Information System (INIS)

    Susan-Resiga, R; Ciocan, T; Muntean, S; De Colombel, T; Leroy, P

    2014-01-01

    We introduce a quasi two-dimensional (Q2D) methodology for assessing the swirling flow exiting the runner of hydraulic turbines at arbitrary operating points, within a wide operating range. The Q2D model does not need actual runner computations, and as a result it represents a surrogate runner model for a-priori assessment of the swirling flow ingested by the draft tube. The axial, radial and circumferential velocity components are computed on a conical section located immediately downstream the runner blades trailing edge, then used as inlet conditions for regular draft tube computations. The main advantage of our model is that it allows the determination of the draft tube losses within the intended turbine operating range in the early design stages of a new or refurbished runner, thus providing a robust and systematic methodology to meet the optimal requirements for the flow at the runner outlet

  17. Long-term success and risk for marathon runners

    International Nuclear Information System (INIS)

    Schueller-Weidekamm, C.

    2010-01-01

    The popularity of marathon running has increased during recent years, which is reflected by the dramatic increase in the number of competitions and participants. Running a marathon itself does not usually cause any severe lesions of the joints but the problems mostly occur during training prior to the marathon. Before the event runners often question whether they can successfully take part in the competition and cope with the pain that might occur during running. In addition to the rare acute trauma, which is in general caused by falls or slipping, chronic injuries are of particular relevance for long distance running. This article describes the typical patterns of injuries to long distance runners, the positive effects of running a marathon and the risk factors for injuries. (orig.) [de

  18. Multiple stress fractures in a young female runner.

    Science.gov (United States)

    Dusek, T; Pećina, M; Loncar-Dusek, M; Bojanic, I

    2004-01-01

    The effect of exercise on female's bone metabolism has received much attention in recent years. We report on unusual case of a female runner with low body mass and amenorrhea, who suffered 4 stress fractures. Three of the stress fractures occurred during her sports career, and the fourth occurred 7 years after the cessation of sports activities. It seems that exercise-induced amenorrhea together with food restriction in the young age may cause long-term consequences on bone metabolism.

  19. Recreational road runners: injuries, training, demographics and physical characteristics

    Directory of Open Access Journals (Sweden)

    Joris Pazin

    2008-07-01

    Full Text Available http://dx.doi.org/10.5007/1980-0037.2008v10n3p277 The purpose of this study was to study recreational road runners in order to identify: their physical characteristics, demographics, running profile (training distance, frequency, duration, and experience and the prevalence of injuries and their association with age, running profile, and other sports practiced. Body mass, height (from which BMI was calculated and waist circumference were also measured. The sample of runners was composed of 115 men who participated in two events organized in Santa Catarina State, Brazil, in 2006: 22nd Maratona de Blumenau and 5th Desafio Praias e Trilhas (Florianópolis. The data were analyzed with descriptive statistics and the chi-square test to identify associations between injury prevalence and other variables (p<.05. The majority of the runners were aged between 18 and 50 years (63.2%, with 36.8% older than 50 years. In terms of educational level 24.3% had attended only elementary school, 35.4% high school, and 40% degree courses. Monthly family income (based on Brazilian minimum wage in Reais - R$ 380.00 varied between R$ 300 and R$ 999 for 23.3% of the runners, between R$ 1000 and R$ 2900 for 45.2%, and above R$ 3000 for 31.3% of them. Seventy two percent of them have been running regularly for more than 6 years, and 57% had received specialist guidance for running; 56.5% run more than 64 km/week. The injury prevalence for one year was 37.7%; BMI and waist circumference were within healthy limits. No associations were found between injury prevalence and other variables studied.

  20. Concentration of Ca in blood of amateur runners using NAA

    Energy Technology Data Exchange (ETDEWEB)

    Kovacs, L.; Zamboni, C. B.; Metairon, S. [Instituto de Pesquisas Energeticas e Nucleares (IPEN / CNEN - SP) - Centro do Reator de Pesquisas Av. Professor Lineu Prestes, 2242 - 05508-000 Sao Paulo, SP (Brazil); Nunes, L. A. S.; Lourenco, T. F.; Macedo, D. V. [Universidade Estadual de Campinas - UNICAMP - Laboratorio de Bioquimica do Exercicio - LABEX Cidade Universitaria 13083-970 - Campinas, SP Brazil - Caixa-Postal: 6109 (Brazil)

    2013-05-06

    In this study the Ca levels were determined in amateur runners blood at LABEX (Laboratorio de Bioquimica do Exercicio - UNICAMP, Brazil), using Neutron Activation Analyses (NAA) technique. The range established at rest (162 - 410 mgL{sup -1}) when compared with control group (51 - 439 mgL{sup -1}) suggests that there is a dependency of these limits in the function of the adopted physical training.

  1. Emotions and trait emotional intelligence among ultra-endurance runners.

    Science.gov (United States)

    Lane, Andrew M; Wilson, Mathew

    2011-07-01

    The aim of this study was to investigate relationships between trait emotional intelligence and emotional state changes over the course of an ultra-endurance foot race covering a route of approximately 175 miles (282 km) and held in set stages over six days. A repeated measures field design that sought to maintain ecological validity was used. Trait emotional intelligence was defined as a relatively stable concept that should predict adaptive emotional states experienced over the duration of the race and therefore associate with pleasant emotions during a 6-stage endurance event. Thirty-four runners completed a self-report measure of trait emotional intelligence before the event started. Participants reported emotional states before and after each of the six races. Repeated measures ANOVA results showed significant variations in emotions over time and a main effect for trait emotional intelligence. Runners high in self-report trait emotional intelligence also reported higher pleasant and lower unpleasant emotions than runners low in trait emotional intelligence. Findings lend support to the notion that trait emotional intelligence associates with adaptive psychological states, suggesting that it may be a key individual difference that explains why some athletes respond to repeated bouts of hard exercise better than others. Future research should test the effectiveness of interventions designed to enhance trait emotional intelligence and examine the attendant impact on emotional responses to intense exercise during multi-stage events. Copyright © 2011. Published by Elsevier Ltd.

  2. CERN runners on the podium for the Escalade race

    CERN Multimedia

    Caroline Duc

    2012-01-01

    For the last race of the season, CERN runners distinguished themselves by notching up third place in the inter-entreprises category of the Escalade, Geneva’s famous running race across the city.   Some of the runners from the CERN team. On Friday 30 November and Saturday 1 December, 35 runners from CERN braved the chilly Geneva weather to take part in the 35th Escalade race. With 81 teams competing in the race, the group representing the Laboratory took third place in the inter-entreprises category, behind the Hôpitaux Universitaires de Genève and the Panards Migros teams.   CERN’s Helenka Przysiezniak, Steffen Doebert and Camille Ruiz Llamas also distinguished themselves individually by finishing eighth, sixth and fourth in their respective categories and Patrick Villeton achieved a very good ranking in the DUC race on Friday evening and in the classic race on Saturday. Congratulations to everyone who participated and see you next ...

  3. An empirical study of race times in recreational endurance runners.

    Science.gov (United States)

    Vickers, Andrew J; Vertosick, Emily A

    2016-01-01

    Studies of endurance running have typically involved elite athletes, small sample sizes and measures that require special expertise or equipment. We examined factors associated with race performance and explored methods for race time prediction using information routinely available to a recreational runner. An Internet survey was used to collect data from recreational endurance runners (N = 2303). The cohort was split 2:1 into a training set and validation set to create models to predict race time. Sex, age, BMI and race training were associated with mean race velocity for all race distances. The difference in velocity between males and females decreased with increasing distance. Tempo runs were more strongly associated with velocity for shorter distances, while typical weekly training mileage and interval training had similar associations with velocity for all race distances. The commonly used Riegel formula for race time prediction was well-calibrated for races up to a half-marathon, but dramatically underestimated marathon time, giving times at least 10 min too fast for half of runners. We built two models to predict marathon time. The mean squared error for Riegel was 381 compared to 228 (model based on one prior race) and 208 (model based on two prior races). Our findings can be used to inform race training and to provide more accurate race time predictions for better pacing.

  4. Risk factors for lower extremity injuries among male marathon runners.

    Science.gov (United States)

    Van Middelkoop, M; Kolkman, J; Van Ochten, J; Bierma-Zeinstra, S M A; Koes, B W

    2008-12-01

    The aim of this study is to identify risk factors for lower extremity injuries in male marathon runners. A random sample of 1500 recreational male marathon runners was drawn. Possible risk factors were obtained from a baseline questionnaire 1 month before the start of the marathon. Information on injuries sustained shortly before or during the marathon was obtained using a post-race questionnaire. Of the 694 male runners who responded to the baseline and post-race questionnaire, 28% suffered a self-reported running injury on the lower extremities in the month before or during the marathon run. More than six times race participation in the previous 12 months [odds ratio (OR) 1.66; confidence interval (CI) 1.08-2.56], a history of running injuries (OR 2.62; CI 1.82-3.78), high education level (OR 0.73; CI 0.51-1.04) and daily smoking (OR 0.23; CI 0.05-1.01) were associated with the occurrence of lower extremity injuries. Among the modifiable risk factor studies, a training distance training is a strong protective factor for knee injuries. Other training characteristics appear to have little or no effect on future injuries.

  5. Unsteady load on an oscillating Kaplan turbine runner

    Science.gov (United States)

    Puolakka, O.; Keto-Tokoi, J.; Matusiak, J.

    2013-02-01

    A Kaplan turbine runner oscillating in turbine waterways is subjected to a varying hydrodynamic load. Numerical simulation of the related unsteady flow is time-consuming and research is very limited. In this study, a simplified method based on unsteady airfoil theory is presented for evaluation of the unsteady load for vibration analyses of the turbine shaft line. The runner is assumed to oscillate as a rigid body in spin and axial heave, and the reaction force is resolved into added masses and dampings. The method is applied on three Kaplan runners at nominal operating conditions. Estimates for added masses and dampings are considered to be of a magnitude significant for shaft line vibration. Moderate variation in the added masses and minor variation in the added dampings is found in the frequency range of interest. Reference results for added masses are derived by solving the boundary value problem for small motions of inviscid fluid using the finite element method. Good correspondence is found in the added mass estimates of the two methods. The unsteady airfoil method is considered accurate enough for design purposes. Experimental results are needed for validation of unsteady load analyses.

  6. Hot Runner Mold Design of Fan Diverter Parts

    Science.gov (United States)

    Juan, D. J.; Cheng, Y. L.

    2017-09-01

    In this study, we discuss the case of plastic parts for the production of fan steering gear shaft parts injection molding, and use POM plastic steel to produce plastic parts from traditional cold runners. Because of the parts have a hole, which need side slide. The runner produce more waste after plastic parts injection make the runner waste account for the cost is relatively high, the cost of stock preparation is relatively increased when the product quantity demanded is great. After the crushing treatment of the waste, the backfill will affect the quality, and in the crushing process, the volume generated will make the operator to withstand up to 130 dB of noise. The actual test results show that the production cycle reduce 6.25%, while the production yield increase by about 5% and material costs reduced by 2% . It can be recovered within a year, not to mention the increase of the quality and reduction the noise on the staff of the benefit is impossible to estimate.

  7. HIGHER PRECISION OF HEART RATE COMPARED WITH VO2 TO PREDICT EXERCISE INTENSITY IN ENDURANCE-TRAINED RUNNERS

    Directory of Open Access Journals (Sweden)

    Victor M. Reis

    2011-03-01

    Full Text Available The aim of the present study was to assess the precision of oxygen uptake with heart rate regression during track running in highly-trained runners. Twelve national and international level male long-distance road runners (age 30.7 ± 5.5 yrs, height 1.71 ± 0.04 m and mass 61.2 ± 5.8 kg with a personal best on the half marathon of 62 min 37 s ± 1 min 22 s participated in the study. Each participant performed, in an all-weather synthetic track five, six min bouts at constant velocity with each bout at an increased running velocity. The starting velocity was 3.33 m·s-1 with a 0.56 m·s-1 increase on each subsequent bout. VO2 and heart rate were measured during the runs and blood lactate was assessed immediately after each run. Mean peak VO2 and mean peak heart rate were, respectively, 76.2 ± 9.7 mL·kg-1·min-1 and 181 ± 13 beats·min-1. The linearity of the regressions between heart rate, running velocity and VO2 were all very high (r > 0.99 with small standard errors of regression (i.e. Sy.x < 5% at the velocity associated with the 2 and 4 mmol·L-1 lactate thresholds. The strong relationships between heart rate, running velocity and VO2 found in this study show that, in highly trained runners, it is possible to have heart rate as an accurate indicator of energy demand and of the running speed. Therefore, in this subject cohort it may be unnecessary to use VO2 to track changes in the subjects' running economy during training periods.

  8. Validations of CFD against detailed velocity and pressure measurements in water turbine runner flow

    Science.gov (United States)

    Nilsson, H.; Davidson, L.

    2003-03-01

    This work compares CFD results with experimental results of the flow in two different kinds of water turbine runners. The runners studied are the GAMM Francis runner and the Hölleforsen Kaplan runner. The GAMM Francis runner was used as a test case in the 1989 GAMM Workshop on 3D Computation of Incompressible Internal Flows where the geometry and detailed best efficiency measurements were made available. In addition to the best efficiency measurements, four off-design operating condition measurements are used for the comparisons in this work. The Hölleforsen Kaplan runner was used at the 1999 Turbine 99 and 2001 Turbine 99 - II workshops on draft tube flow, where detailed measurements made after the runner were used as inlet boundary conditions for the draft tube computations. The measurements are used here to validate computations of the flow in the runner.The computations are made in a single runner blade passage where the inlet boundary conditions are obtained from an extrapolation of detailed measurements (GAMM) or from separate guide vane computations (Hölleforsen). The steady flow in a rotating co-ordinate system is computed. The effects of turbulence are modelled by a low-Reynolds number k- turbulence model, which removes some of the assumptions of the commonly used wall function approach and brings the computations one step further.

  9. Serum biochemistry and morbidity among runners presenting for medical care after an Australian mountain ultramarathon.

    Science.gov (United States)

    Reid, Stephen A; King, M Jonathan

    2007-07-01

    To determine if exercise-associated hyponatremia (EAH) was a cause of morbidity among runners requiring medical care at an Australian mountain ultramarathon. Case series. Six Foot Track mountain ultramarathon, New South Wales, Australia, March 2006. Runners presenting to the medical facility. Serum biochemistry. No cases of exercise-associated hyponatremia were identified among 9 athletes (from 775 starters) who were treated with intravenous fluid therapy. Unwell runners had a mean serum (Na) of 143 mmol/L (range 138-147 mmol/L). All runners tested had elevated serum urea and creatinine concentrations. In this setting, EAH was not a significant cause of morbidity.

  10. A prospective study on time to recovery in 254 injured novice runners.

    Directory of Open Access Journals (Sweden)

    Rasmus Oestergaard Nielsen

    Full Text Available Describe the diagnoses and the time to recovery of running-related injuries in novice runners.Prospective cohort study on injured runners.This paper is a secondary data analysis of a 933-person cohort study (DANO-RUN aimed at characterizing risk factors for injury in novice runners. Among those sustaining running-related injuries, the types of injuries and time to recovery is described in the present paper. All injured runners were diagnosed after a thorough clinical examination and then followed prospectively during their recovery. If they recovered completely from injury, time to recovery of each injury was registered.A total of 254 runners were injured. The proportion of runners diagnosed with medial tibial stress syndrome was 15%, 10% for patellofemoral pain, 9% for medial meniscal injury, 7% for Achilles tendinopathy and 5% for plantar fasciitis. Among the 220 runners (87% recovering from their injury, the median time to recovery was 71 days (minimum  = 9 days, maximum  = 617 days.Medial tibial stress syndrome was the most common injury followed by patellofemoral pain, medial meniscal injury and Achilles tendinopathy. Half of the injured runners were unable to run 2×500 meters without pain after 10 weeks. Almost 5% of the injured runners received surgical treatment.

  11. Variation in Foot Strike Patterns among Habitually Barefoot and Shod Runners in Kenya.

    Science.gov (United States)

    Lieberman, Daniel E; Castillo, Eric R; Otarola-Castillo, Erik; Sang, Meshack K; Sigei, Timothy K; Ojiambo, Robert; Okutoyi, Paul; Pitsiladis, Yannis

    2015-01-01

    Runners are often categorized as forefoot, midfoot or rearfoot strikers, but how much and why do individuals vary in foot strike patterns when running on level terrain? This study used general linear mixed-effects models to explore both intra- and inter-individual variations in foot strike pattern among 48 Kalenjin-speaking participants from Kenya who varied in age, sex, body mass, height, running history, and habitual use of footwear. High speed video was used to measure lower extremity kinematics at ground contact in the sagittal plane while participants ran down 13 meter-long tracks with three variables independently controlled: speed, track stiffness, and step frequency. 72% of the habitually barefoot and 32% of the habitually shod participants used multiple strike types, with significantly higher levels of foot strike variation among individuals who ran less frequently and who used lower step frequencies. There was no effect of sex, age, height or weight on foot strike angle, but individuals were more likely to midfoot or forefoot strike when they ran on a stiff surface, had a high preferred stride frequency, were habitually barefoot, and had more experience running. It is hypothesized that strike type variation during running, including a more frequent use of forefoot and midfoot strikes, used to be greater before the introduction of cushioned shoes and paved surfaces.

  12. Variation in Foot Strike Patterns among Habitually Barefoot and Shod Runners in Kenya.

    Directory of Open Access Journals (Sweden)

    Daniel E Lieberman

    Full Text Available Runners are often categorized as forefoot, midfoot or rearfoot strikers, but how much and why do individuals vary in foot strike patterns when running on level terrain? This study used general linear mixed-effects models to explore both intra- and inter-individual variations in foot strike pattern among 48 Kalenjin-speaking participants from Kenya who varied in age, sex, body mass, height, running history, and habitual use of footwear. High speed video was used to measure lower extremity kinematics at ground contact in the sagittal plane while participants ran down 13 meter-long tracks with three variables independently controlled: speed, track stiffness, and step frequency. 72% of the habitually barefoot and 32% of the habitually shod participants used multiple strike types, with significantly higher levels of foot strike variation among individuals who ran less frequently and who used lower step frequencies. There was no effect of sex, age, height or weight on foot strike angle, but individuals were more likely to midfoot or forefoot strike when they ran on a stiff surface, had a high preferred stride frequency, were habitually barefoot, and had more experience running. It is hypothesized that strike type variation during running, including a more frequent use of forefoot and midfoot strikes, used to be greater before the introduction of cushioned shoes and paved surfaces.

  13. Predictor variables for a half marathon race time in recreational male runners

    Directory of Open Access Journals (Sweden)

    Rüst CA

    2011-08-01

    Full Text Available Christoph Alexander Rüst1, Beat Knechtle1,2, Patrizia Knechtle2, Ursula Barandun1, Romuald Lepers3, Thomas Rosemann11Institute of General Practice and Health Services Research, University of Zurich, Zurich, Switzerland; 2Gesundheitszentrum St Gallen, St Gallen, Switzerland; 3INSERM U887, University of Burgundy, Faculty of Sport Sciences, Dijon, FranceAbstract: The aim of this study was to investigate predictor variables of anthropometry, training, and previous experience in order to predict a half marathon race time for future novice recreational male half marathoners. Eighty-four male finishers in the ‘Half Marathon Basel’ completed the race distance within (mean and standard deviation, SD 103.9 (16.5 min, running at a speed of 12.7 (1.9 km/h. After multivariate analysis of the anthropometric characteristics, body mass index (r = 0.56, suprailiacal (r = 0.36 and medial calf skin fold (r = 0.53 were related to race time. For the variables of training and previous experience, speed in running of the training sessions (r = –0.54 were associated with race time. After multivariate analysis of both the significant anthropometric and training variables, body mass index (P = 0.0150 and speed in running during training (P = 0.0045 were related to race time. Race time in a half marathon might be partially predicted by the following equation (r2 = 0.44: Race time (min = 72.91 + 3.045 * (body mass index, kg/m2 –3.884 * (speed in running during training, km/h for recreational male runners. To conclude, variables of both anthropometry and training were related to half marathon race time in recreational male half marathoners and cannot be reduced to one single predictor variable.Keywords: anthropometry, body fat, skin-folds, training, endurance

  14. Factors affecting running economy in trained distance runners.

    Science.gov (United States)

    Saunders, Philo U; Pyne, David B; Telford, Richard D; Hawley, John A

    2004-01-01

    Running economy (RE) is typically defined as the energy demand for a given velocity of submaximal running, and is determined by measuring the steady-state consumption of oxygen (VO2) and the respiratory exchange ratio. Taking body mass (BM) into consideration, runners with good RE use less energy and therefore less oxygen than runners with poor RE at the same velocity. There is a strong association between RE and distance running performance, with RE being a better predictor of performance than maximal oxygen uptake (VO2max) in elite runners who have a similar VO2max). RE is traditionally measured by running on a treadmill in standard laboratory conditions, and, although this is not the same as overground running, it gives a good indication of how economical a runner is and how RE changes over time. In order to determine whether changes in RE are real or not, careful standardisation of footwear, time of test and nutritional status are required to limit typical error of measurement. Under controlled conditions, RE is a stable test capable of detecting relatively small changes elicited by training or other interventions. When tracking RE between or within groups it is important to account for BM. As VO2 during submaximal exercise does not, in general, increase linearly with BM, reporting RE with respect to the 0.75 power of BM has been recommended. A number of physiological and biomechanical factors appear to influence RE in highly trained or elite runners. These include metabolic adaptations within the muscle such as increased mitochondria and oxidative enzymes, the ability of the muscles to store and release elastic energy by increasing the stiffness of the muscles, and more efficient mechanics leading to less energy wasted on braking forces and excessive vertical oscillation. Interventions to improve RE are constantly sought after by athletes, coaches and sport scientists. Two interventions that have received recent widespread attention are strength training and

  15. Effect of 8 weeks of concurrent plyometric and running training on spatiotemporal and physiological variables of novice runners.

    Science.gov (United States)

    Gómez-Molina, Josué; Ogueta-Alday, Ana; Camara, Jesus; Stickley, Christopher; García-López, Juan

    2018-03-01

    Concurrent plyometric and running training has the potential to improve running economy (RE) and performance through increasing muscle strength and power, but the possible effect on spatiotemporal parameters of running has not been studied yet. The aim of this study was to compare the effect of 8 weeks of concurrent plyometric and running training on spatiotemporal parameters and physiological variables of novice runners. Twenty-five male participants were randomly assigned into two training groups; running group (RG) (n = 11) and running + plyometric group (RPG) (n = 14). Both groups performed 8 weeks of running training programme, and only the RPG performed a concurrent plyometric training programme (two sessions per week). Anthropometric, physiological (VO 2max , heart rate and RE) and spatiotemporal variables (contact and flight times, step rate and length) were registered before and after the intervention. In comparison to RG, the RPG reduced step rate and increased flight times at the same running speeds (P running training entails a reduction in step rate, as well as increases in VT speed, RCT speed, peak speed and VO 2max . Athletes could benefit from plyometric training in order to improve their strength, which would contribute to them attaining higher running speeds.

  16. Development of a more fish-tolerant turbine runner, advanced hydropower turbine project

    International Nuclear Information System (INIS)

    Cook, T.C.; Hecker, G.E.

    1997-02-01

    Alden Research Laboratory, Inc. (ARL) and Northern Research and Engineering Corporation (NREC) conducted a research program to develop a turbine runner which will minimize fish injury and mortality at hydroelectric projects. ARL?NREC have developed a runner shape which minimizes the number of blade leading edges, reduces the pressure versus time and the velocity versus distance gradients within the runner, minimizes or eliminates the clearance between the runner and runner housing, and maximizes the size of the flow passages, all with minimal penalty on turbine efficiency. An existing pump impeller provided the starting point for developing the fish tolerant turbine runner. The Hidrostal pump is a single bladed combined screw/centrifugal pump which has been proven to transport fish with minimal injury. The focus of the ARL/NREC research project was to develop a new runner geometry which is effective in downstream fish passage and hydroelectric power generation. A flow of 1,000 cfs and a head in the range of 75 ft to 100 ft were selected for conceptual design of the new runner. Conceptual design of the new runner began with a re-evaluation of studies which have been previously conducted to identify probable sources of injury to fish passing through hydraulic turbines. Criteria relative to hydraulic characteristics which are favorable for fish passage were prepared based on a reassessment of the available information. Important criteria used to develop the new runner design included low pressure change rates, minimum absolute pressures, and minimum shear. Other criteria which are reflected in the runner design are a minimum number of blades (only two), minimum total length of leading edges, and large flow passages. 86 figs., 5 tabs

  17. Runners maintain locomotor-respiratory coupling following isocapnic voluntary hyperpnea to task failure.

    Science.gov (United States)

    Stickford, Abigail S L; Stickford, Jonathon L; Tanner, David A; Stager, Joel M; Chapman, Robert F

    2015-11-01

    Evidence has long suggested that mammalian ventilatory and locomotor rhythms are linked, yet determinants and implications of locomotor-respiratory coupling (LRC) continue to be investigated. Anecdotally, respiratory muscle fatigue seen at the end of heavy exercise may result in an uncoupling of movement-ventilation rhythms; however, there is no scientific evidence to substantiate this claim. We sought to determine whether or not fatigue of the respiratory muscles alters locomotor-respiratory coupling patterns typically observed in highly trained individuals while running. A related query was to examine the relationship between the potential changes in LRC and measures of running economy. Twelve male distance runners ran at four submaximal workloads (68-89 % VO2peak) on two separate days while LRC was quantified. One LRC trial served as a control (CON), while the other was performed following an isocapnic voluntary hyperpnea to task failure to induce respiratory muscle fatigue (FT+). LRC was assessed as stride-to-breathing frequency ratios (SF/fB) and degree of LRC (percentage of breaths occurring during the same decile of the step cycle). Hyperpnea resulted in significant declines in maximal voluntary inspiratory (MIP) and expiratory (MEP) mouth pressures (ΔMIP = -10 ± 12 cm H2O; ΔMEP = -6 ± 9 cm H2O). There were no differences in minute ventilation between CON and FT+ (CON, all speeds pooled = 104 ± 25 L min(-1); FT+ pooled = 106 ± 23 L min(-1)). Stride frequency was not different between trials; however, breathing frequency was significantly greater during FT+ compared to CON at all speeds (CON pooled = 47 ± 10 br min(-1); FT+ pooled = 52 ± 9 br min(-1)), resulting in smaller corresponding SF/fB. Yet, the degree of LRC was the same during CON and FT+ (CON pooled = 63 ± 15 %; FT+ pooled = 64 ± 18 %). The results indicate that trained runners are able to continue entraining breath and step cycles, despite marked changes in exercise breathing frequency

  18. High-speed scanning ablation of dental hard tissues with a λ = 9.3 μm CO2 laser: adhesion, mechanical strength, heat accumulation, and peripheral thermal damage

    Science.gov (United States)

    Nguyen, Daniel; Chang, Kwang; Hedayatollahnajafi, Saba; Staninec, Michal; Chan, Kenneth; Lee, Robert; Fried, Daniel

    2011-07-01

    CO2 lasers can be operated at high laser pulse repetition rates for the rapid and precise removal of dental decay. Excessive heat accumulation and peripheral thermal damage is a concern when using high pulse repetition rates. Peripheral thermal damage can adversely impact the mechanical strength of the irradiated tissue, particularly for dentin, and reduce the adhesion characteristics of the modified surfaces. The interpulpal temperature rise was recorded using microthermocouples situated at the roof of the pulp chamber on teeth that were occlusally ablated using a rapidly-scanned CO2 laser operating at 9.3 μm with a pulse duration of 10 to 15 μs and repetition rate of 300 Hz over a 2 min time course. The adhesion strength of laser treated enamel and dentin surfaces was measured for various laser scanning parameters with and without post-ablation acid etching using the single-plane shear test. The mechanical strength of laser-ablated dentin surfaces were determined via the four-point bend test and compared to control samples prepared with 320 grit wet sand paper to simulate conventional preparations. Thermocouple measurements indicated that the temperature remained below ambient temperature if water-cooling was used. There was no discoloration of either dentin or enamel laser treated surfaces, the surfaces were uniformly ablated, and there were no cracks visible. Four-point bend tests yielded mean mechanical strengths of 18.2 N (s.d. = 4.6) for ablated dentin and 18.1 N (s.d. = 2.7) for control (p > 0.05). Shear tests yielded mean bond strengths approaching 30 MPa for both enamel and dentin under certain irradiation conditions. These values were slightly lower than nonirradiated acid-etched control samples. Additional studies are needed to determine if the slightly lower bond strength than the acid-etched control samples is clinically significant. These measurements demonstrate that enamel and dentin surfaces can be rapidly ablated by CO2 lasers with minimal

  19. 76 FR 16700 - Importation of French Beans and Runner Beans From the Republic of Kenya Into the United States

    Science.gov (United States)

    2011-03-25

    .... APHIS-2010-0101] RIN 0579-AD39 Importation of French Beans and Runner Beans From the Republic of Kenya... French beans and runner beans from the Republic of Kenya into the United States. As a condition of entry... French beans and runner beans from the Republic of Kenya into the United States while continuing to...

  20. The Runners and Injury Longitudinal Study: Injury Recovery Supplement (TRAILS_IR)

    Science.gov (United States)

    2013-08-01

    2) develop statistical models that integrate biomechanical, behavioral, and psychological risk factors for injury, (3) determine the length of...Running Mechanics and Flexibility Between Runners in Minimalist and Traditional Footwear ”......14...annual meeting entitled “Differences in Running Mechanics and Flexibility between Runners in Minimalist and Traditional Footwear ”. The following

  1. Evaluation of the dynamic behavior of a Pelton runner based on strain gauge measurements

    Science.gov (United States)

    Mack, Reiner; Probst, Christian

    2016-11-01

    A reliable mechanical design of Pelton runners is very important in the layout of new installations and modernizations. Especially in horizontal machines, where the housing is not embedded into concrete, a rupture of a runner bucket can have severe consequences. Even if a crack in the runner is detected on time, the outage time that follows the malfunction of the runner is shortening the return of investment. It is a fact that stresses caused by the runner rotation and the jet forces are superposed by high frequent dynamic stresses. In case of resonance it even can be the dominating effect that is limiting the lifetime of a runner. Therefore a clear understanding of the dynamic mechanisms is essential for a safe runner design. This paper describes the evaluation of the dynamic behavior of a Pelton runner installed in a model turbine based on strain gauge measurements. Equipped with strain gauges at the root area of the buckets, the time responses of the strains under the influence of various operational parameters were measured. As a result basic theories for the jet bucket excitation were verified and the influence of the water mass was detected by evaluating the frequency shift in case of resonance. Furthermore, the influence of the individual bucket masses onto the dynamic behaviour for different mode shapes got measured.

  2. Gender differences in gait kinematics in runners with iliotibial band syndrome.

    Science.gov (United States)

    Phinyomark, A; Osis, S; Hettinga, B A; Leigh, R; Ferber, R

    2015-12-01

    Atypical running gait biomechanics are considered a primary factor in the etiology of iliotibial band syndrome (ITBS). However, a general consensus on the underpinning kinematic differences between runners with and without ITBS is yet to be reached. This lack of consensus may be due in part to three issues: gender differences in gait mechanics, the preselection of discrete biomechanical variables, and/or relatively small sample sizes. Therefore, this study was designed to address two purposes: (a) examining differences in gait kinematics for male and female runners experiencing ITBS at the time of testing and (b) assessing differences in gait kinematics between healthy gender- and age-matched runners as compared with their ITBS counterparts using waveform analysis. Ninety-six runners participated in this study: 48 ITBS and 48 healthy runners. The results show that female ITBS runners exhibited significantly greater hip external rotation compared with male ITBS and female healthy runners. On the contrary, male ITBS runners exhibited significantly greater ankle internal rotation compared with healthy males. These results suggest that care should be taken to account for gender when investigating the biomechanical etiology of ITBS. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. Kenyan and Ethiopian distance runners: what makes them so good?

    Science.gov (United States)

    Wilber, Randall L; Pitsiladis, Yannis P

    2012-06-01

    Since the 1968 Mexico City Olympics, Kenyan and Ethiopian runners have dominated the middle- and long-distance events in athletics and have exhibited comparable dominance in international cross-country and road-racing competition. Several factors have been proposed to explain the extraordinary success of the Kenyan and Ethiopian distance runners, including (1) genetic predisposition, (2) development of a high maximal oxygen uptake as a result of extensive walking and running at an early age, (3) relatively high hemoglobin and hematocrit, (4) development of good metabolic "economy/efficiency" based on somatotype and lower limb characteristics, (5) favorable skeletal-muscle-fiber composition and oxidative enzyme profile, (6) traditional Kenyan/Ethiopian diet, (7) living and training at altitude, and (8) motivation to achieve economic success. Some of these factors have been examined objectively in the laboratory and field, whereas others have been evaluated from an observational perspective. The purpose of this article is to present the current data relative to factors that potentially contribute to the unprecedented success of Kenyan and Ethiopian distance runners, including recent studies that examined potential links between Kenyan and Ethiopian genotype characteristics and elite running performance. In general, it appears that Kenyan and Ethiopian distance-running success is not based on a unique genetic or physiological characteristic. Rather, it appears to be the result of favorable somatotypical characteristics lending to exceptional biomechanical and metabolic economy/efficiency; chronic exposure to altitude in combination with moderate-volume, high-intensity training (live high + train high), and a strong psychological motivation to succeed athletically for the purpose of economic and social advancement.

  4. Numerical investigation of tip clearance cavitation in Kaplan runners

    Science.gov (United States)

    Nikiforova, K.; Semenov, G.; Kuznetsov, I.; Spiridonov, E.

    2016-11-01

    There is a gap between the Kaplan runner blade and the shroud that makes for a special kind of cavitation: cavitation in the tip leakage flow. Two types of cavitation caused by the presence of clearance gap are known: tip vortex cavitation that appears at the core of the rolled up vortex on the blade suction side and tip clearance cavitation that appears precisely in the gap between the blade tip edge and the shroud. In the context of this work numerical investigation of the model Kaplan runner has been performed taking into account variable tip clearance for several cavitation regimes. The focus is put on investigation of structure and origination of mechanism of cavitation in the tip leakage flow. Calculations have been performed with the help of 3-D unsteady numerical model for two-phase medium. Modeling of turbulent flow in this work has been carried out using full equations of Navier-Stokes averaged by Reynolds with correction for streamline curvature and system rotation. For description of this medium (liquid-vapor) simplification of Euler approach is used; it is based on the model of interpenetrating continuums, within the bounds of this two- phase medium considered as a quasi-homogeneous mixture with the common velocity field and continuous distribution of density for both phases. As a result, engineering techniques for calculation of cavitation conditioned by existence of tip clearance in model turbine runner have been developed. The detailed visualization of the flow was carried out and vortex structure on the suction side of the blade was reproduced. The range of frequency with maximum value of pulsation was assigned and maximum energy frequency was defined; it is based on spectral analysis of the obtained data. Comparison between numerical computation results and experimental data has been also performed. The location of cavitation zone has a good agreement with experiment for all analyzed regimes.

  5. Discrete and continuous joint coupling relationships in uninjured recreational runners.

    Science.gov (United States)

    Dierks, Tracy A; Davis, Irene

    2007-06-01

    Abnormal joint coupling is thought to be related to overuse injuries in runners. However, researchers do not yet know what constitutes normal joint coupling during running, which makes abnormal coupling difficult to define. Lower extremity kinematics were collected from 40 recreational runners during stance. Joint coupling methods were applied and, for each method, means and both within- and between-subject variability were calculated. The 95% confidence interval was used to compare differences across coupling relationships and periods of stance. Timing between rearfoot eversion, tibial internal rotation, and knee flexion were relatively synchronous while relationships involving knee internal rotation were more asynchronous. The excursion ratios showed that every 2 degrees of rearfoot eversion was coupled with 1 degrees of both tibial internal rotation and knee internal rotation. Vector coding results showed that just beyond maximum loading, all joint coupling relationships resulted in relatively equal amounts of motion, while the within-subject variability was similar throughout stance. The continuous relative phase results showed that the most out-of-phase coupling occurred in the periods around heel-strike and toe-off while the most in-phase coupling occurred in the period just beyond maximum loading of the leg. The continuous relative phase within-subject variability was greatest at the periods around heel-strike and toe-off and smallest just beyond maximum loading. With a better understanding of joint coupling in uninjured runners, these data will help to serve as a reference for future studies investigating the relationship between running injuries and abnormal joint coupling.

  6. PlateRunner: A Search Engine to Identify EMR Boilerplates.

    Science.gov (United States)

    Divita, Guy; Workman, T Elizabeth; Carter, Marjorie E; Redd, Andrew; Samore, Matthew H; Gundlapalli, Adi V

    2016-01-01

    Medical text contains boilerplated content, an artifact of pull-down forms from EMRs. Boilerplated content is the source of challenges for concept extraction on clinical text. This paper introduces PlateRunner, a search engine on boilerplates from the US Department of Veterans Affairs (VA) EMR. Boilerplates containing concepts should be identified and reviewed to recognize challenging formats, identify high yield document titles, and fine tune section zoning. This search engine has the capability to filter negated and asserted concepts, save and search query results. This tool can save queries, search results, and documents found for later analysis.

  7. Amir's Guilt in Khaled Hosseini's the Kite Runner

    OpenAIRE

    Lambe, Lordna G.L; Basuki, Ribut

    2013-01-01

    This paper emphasizes guilt as the main issue portrayed in Khaled Hosseini's The Kite Runner through its main character, Amir. Guilt discussed in this paper is defined as a feeling produced from a behavior that is related to a failure, a wrong doing, or even a sin. This paper discusses the way Amir deals with his guilt since it needs to be redeemed even through suffering. In this paper, I maintain that Amir bears not only his personal guilt yet also his familial and societal guilt. Amir's per...

  8. Prediction of half-marathon race time in recreational female and male runners.

    Science.gov (United States)

    Knechtle, Beat; Barandun, Ursula; Knechtle, Patrizia; Zingg, Matthias A; Rosemann, Thomas; Rüst, Christoph A

    2014-01-01

    Half-marathon running is of high popularity. Recent studies tried to find predictor variables for half-marathon race time for recreational female and male runners and to present equations to predict race time. The actual equations included running speed during training for both women and men as training variable but midaxillary skinfold for women and body mass index for men as anthropometric variable. An actual study found that percent body fat and running speed during training sessions were the best predictor variables for half-marathon race times in both women and men. The aim of the present study was to improve the existing equations to predict half-marathon race time in a larger sample of male and female half-marathoners by using percent body fat and running speed during training sessions as predictor variables. In a sample of 147 men and 83 women, multiple linear regression analysis including percent body fat and running speed during training units as independent variables and race time as dependent variable were performed and an equation was evolved to predict half-marathon race time. For men, half-marathon race time might be predicted by the equation (r(2) = 0.42, adjusted r(2) = 0.41, SE = 13.3) half-marathon race time (min) = 142.7 + 1.158 × percent body fat (%) - 5.223 × running speed during training (km/h). The predicted race time correlated highly significantly (r = 0.71, p marathon race time might be predicted by the equation (r(2) = 0.68, adjusted r(2) = 0.68, SE = 9.8) race time (min) = 168.7 + 1.077 × percent body fat (%) - 7.556 × running speed during training (km/h). The predicted race time correlated highly significantly (r = 0.89, p < 0.0001) to the achieved race time. The coefficients of determination of the models were slightly higher than for the existing equations. Future studies might include physiological variables to increase the coefficients of determination of the

  9. Reliability of video-based identification of footstrike pattern and video time frame at initial contact in recreational runners

    DEFF Research Database (Denmark)

    Damsted, Camma; Larsen, L H; Nielsen, R.O.

    2015-01-01

    and video time frame at initial contact during treadmill running using two-dimensional (2D) video recordings. METHODS: Thirty-one recreational runners were recorded twice, 1 week apart, with a high-speed video camera. Two blinded raters evaluated each video twice with an interval of at least 14 days....... RESULTS: Kappa values for within-day identification of footstrike pattern revealed intra-rater agreement of 0.83-0.88 and inter-rater agreement of 0.50-0.63. Corresponding figures for between-day identification of footstrike pattern were 0.63-0.69 and 0.41-0.53, respectively. Identification of video time...... in 36% of the identifications (kappa=0.41). The 95% limits of agreement for identification of video time frame at initial contact may, at times, allow for different identification of footstrike pattern. Clinicians should, therefore, be encouraged to continue using clinical 2D video setups for intra...

  10. Load management in elite German distance runners during 3-weeks of high-altitude training.

    Science.gov (United States)

    Sperlich, Billy; Achtzehn, Silvia; de Marées, Markus; von Papen, Henning; Mester, Joachim

    2016-06-01

    There is a debate on the optimal way of monitoring training loads in elite endurance athletes especially during altitude training camps. In this case report, including nine members of the German national middle distance running team, we describe a practical approach to monitor the psychobiological stress markers during 21 days of altitude training (~2100 m above sea-level) to estimate the training load and to control muscle damage, fatigue, and/or chronic overreaching. Daily examination included: oxygen saturation of hemoglobin, resting heart rate, body mass, body and sleep perception, capillary blood concentration of creatine kinase. Every other day, venous serum concentration of blood urea nitrogen, venous blood concentration of hemoglobin, hematocrit, red and white blood cell were measured. If two or more of the above-mentioned stress markers were beyond or beneath the athlete's normal individual range, the training load of the subsequent training session was reduced. Running speed at 3 mmol L(-1) blood lactate (V3) improved and no athlete showed any signs of underperformance, chronic muscle damage, decrease body and sleep perception as well as activated inflammatory process during the 21 days. The dense screening of biomarkers in the present case study may stimulate further research to identify candidate markers for load monitoring in elite middle- and long-distance runners during a training camp at altitude. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

  11. The effects of creatine and glycerol hyperhydration on running economy in well trained endurance runners

    Directory of Open Access Journals (Sweden)

    Beis Lukas Y

    2011-12-01

    Full Text Available Abstract Background Ingestion of creatine (Cr and glycerol (Gly has been reported to be an effective method in expanding water compartments within the human body, attenuating the rise in heart rate (HR and core temperature (Tcore during exercise in the heat. Despite these positive effects, a substantial water retention could potentially impair endurance performance through increasing body mass (BM and consequently impacting negatively on running economy (RE. The objective of the present study was to investigate the effects of a combined Cr and Gly supplementation on thermoregulatory and cardiovascular responses and RE during running for 30 min at speed corresponding to 60% of maximal oxygen uptake (V˙O2max in hot and cool conditions. Methods Cr·H2O (11.4 g, Gly (1 g·kg-1 BM and Glucose polymer (75 g were administered twice daily to 15 male endurance runners during a 7-day period. Exercise trials were conducted pre- and post-supplementation at 10 and 35°C and 70% relative humidity. Results BM and total body water increased by 0.90 ± 0.40 kg (P P V˙O2 and therefore RE. Both HR and Tcore were attenuated significantly after supplementation (P Conclusions Combining Cr and Gly is effective in reducing thermal and cardiovascular strain during exercise in the heat without negatively impacting on RE.

  12. Strain gauge measurement uncertainties on hydraulic turbine runner blade

    International Nuclear Information System (INIS)

    Arpin-Pont, J; Gagnon, M; Tahan, S A; Coutu, A; Thibault, D

    2012-01-01

    Strains experimentally measured with strain gauges can differ from those evaluated using the Finite Element (FE) method. This difference is due mainly to the assumptions and uncertainties inherent to each method. To circumvent this difficulty, we developed a numerical method based on Monte Carlo simulations to evaluate measurement uncertainties produced by the behaviour of a unidirectional welded gauge, its position uncertainty and its integration effect. This numerical method uses the displacement fields of the studied part evaluated by an FE analysis. The paper presents a study case using in situ data measured on a hydraulic turbine runner. The FE analysis of the turbine runner blade was computed, and our numerical method used to evaluate uncertainties on strains measured at five locations with welded strain gauges. Then, measured strains and their uncertainty ranges are compared to the estimated strains. The uncertainty ranges obtained extended from 74 με to 165 με. Furthermore, the biases observed between the median of the uncertainty ranges and the FE strains varied from −36 to 36 με. Note that strain gauge measurement uncertainties depend mainly on displacement fields and gauge geometry.

  13. INFLUENCE OF INJURY ON DYNAMIC POSTURAL CONTROL IN RUNNERS.

    Science.gov (United States)

    Meardon, Stacey; Klusendorf, Anna; Kernozek, Thomas

    2016-06-01

    Injury has been linked with altered postural control in active populations. The association between running injury and dynamic postural control has not been examined. The purpose of this study was to examine dynamic postural control in injured and uninjured runners using the Star Excursion Balance Test (SEBT), Time to Stabilization (TTS) of ground reaction forces following a single-leg landing, and postural stability indices reflecting the fluctuations in GRFs during single-leg landing and stabilization tasks (forward and lateral hop). It was hypothesized that dynamic postural control differences would exist between runners with a history of injury that interrupted training for ≥7 days (INJ) when compared to runners without injury (CON). Case-control study. Twenty-two INJ (14 F, 8 M; 23.7 ± 2.1 y; 22.3 ± 2.8 kg/m2; 29.5 ± 16.3 mi/wk) currently running > 50% pre-injury mileage without pain were compared with twenty-two matched CON (14F, 8M; 22.7 ± 1.2 y; 22.7 ± 2.7 kg/m2; 31.2 ± 19.6 mi/wk). INJ group was stratified by site of injury into two groups (Hip/Thigh/Knee and Lower Leg/Ankle/Foot) for secondary analysis. Leg length-normalized anterior, posterolateral, and posteromedial reach distances on the SEBT, medial/lateral and anterior/posterior ground reaction force TTS, directional postural stability indices, and a composite dynamic postural stability index (DPSI), were assessed using mixed model ANOVA (α=0.05) and effect sizes (d). No group X direction interaction or group differences were observed for the SEBT (p=0.51, 0.71) or TTS (p=0.83, 0.72) measures. A group X direction interaction was found for postural stability indices during the forward landing task (ppostural stability index (VPSI) (p=0.01 for both, d=0.80, 0.95) and DPSI (p=0.01, 0.02, d=0.75, 0.93) when compared to CON suggesting impaired balance control. A group X direction interaction was also found for postural stability indices during the lateral landing

  14. Predictor variables for half marathon race time in recreational female runners

    Directory of Open Access Journals (Sweden)

    Beat Knechtle

    2011-01-01

    Full Text Available INTRODUCTION: The relationship between skin-fold thickness and running performance has been investigated from 100 m to the marathon distance, except the half marathon distance. OBJECTIVE: To investigate whether anthropometry characteristics or training practices were related to race time in 42 recreational female half marathoners to determine the predictor variables of half-marathon race time and to inform future novice female half marathoners. METHODS: Observational field study at the 'Half Marathon Basel' in Switzerland. RESULTS: In the bivariate analysis, body mass (r = 0.60, body mass index (r = 0.48, body fat (r = 0.56, skin-fold at pectoral (r = 0.61, mid-axilla (r = 0.69, triceps (r = 0.49, subscapular (r = 0.61, abdominal (r = 0.59, suprailiac (r = 0.55 medial calf (r = 0.53 site, and speed of the training sessions (r = -0.68 correlated to race time. Mid-axilla skin-fold (p = 0.04 and speed of the training sessions (p = 0.0001 remained significant after multi-variate analysis. Race time in a half marathon might be predicted by the following equation (r² = 0.71: Race time (min = 166.7 + 1.7x (mid-axilla skin-fold, mm - 6.4x (speed in training, km/h. Running speed during training was related to skinfold thickness at mid-axilla (r = -0.31, subscapular (r = -0.38, abdominal (r = -0.44, suprailiacal (r = -0.41, the sum of eight skin-folds (r = -0.36 and percent body fat (r = -0.31. CONCLUSION: Anthropometric and training variables were related to half-marathon race time in recreational female runners. Skin-fold thicknesses at various upper body locations were related to training intensity. High running speed in training appears to be important for fast half-marathon race times and may reduce upper body skin-fold thicknesses in recreational female half marathoners.

  15. Predictor variables for half marathon race time in recreational female runners.

    Science.gov (United States)

    Knechtle, Beat; Knechtle, Patrizia; Barandun, Ursula; Rosemann, Thomas; Lepers, Romuald

    2011-01-01

    The relationship between skin-fold thickness and running performance has been investigated from 100 m to the marathon distance, except the half marathon distance. To investigate whether anthropometry characteristics or training practices were related to race time in 42 recreational female half marathoners to determine the predictor variables of half-marathon race time and to inform future novice female half marathoners. Observational field study at the 'Half Marathon Basel' in Switzerland. In the bivariate analysis, body mass (r = 0.60), body mass index (r = 0.48), body fat (r = 0.56), skin-fold at pectoral (r = 0.61), mid-axilla (r = 0.69), triceps (r = 0.49), subscapular (r = 0.61), abdominal (r = 0.59), suprailiac (r = 0.55) medial calf (r = 0.53) site, and speed of the training sessions (r = -0.68) correlated to race time. Mid-axilla skin-fold (p = 0.04) and speed of the training sessions (p = 0.0001) remained significant after multi-variate analysis. Race time in a half marathon might be predicted by the following equation (r² = 0.71): Race time (min) = 166.7 + 1.7x (mid-axilla skin-fold, mm) - 6.4x (speed in training, km/h). Running speed during training was related to skinfold thickness at mid-axilla (r = -0.31), subscapular (r = -0.38), abdominal (r = -0.44), suprailiacal (r = -0.41), the sum of eight skin-folds (r = -0.36) and percent body fat (r = -0.31). Anthropometric and training variables were related to half-marathon race time in recreational female runners. Skin-fold thicknesses at various upper body locations were related to training intensity. High running speed in training appears to be important for fast half-marathon race times and may reduce upper body skin-fold thicknesses in recreational female half marathoners.

  16. Propylthiouracil and peripheral neuropathy

    Directory of Open Access Journals (Sweden)

    Valentina Van Boekel

    1992-06-01

    Full Text Available Peripheral neuropathy is a rare manifestation in hyperthyroidism. We describe the neurological manifestations of a 38 year old female with Graves' disease who developed peripheral neuropathy in the course of her treatment with propylthiouracil. After the drug was tapered off, the neurological signs disappeared. Therefore, we call attention for a possible toxic effect on peripheral nervous system caused by this drug.

  17. Speed mathematics

    CERN Document Server

    Handley, Bill

    2012-01-01

    This new, revised edition of the bestselling Speed Mathematics features new chapters on memorising numbers and general information, calculating statistics and compound interest, square roots, logarithms and easy trig calculations. Written so anyone can understand, this book teaches simple strategies that will enable readers to make lightning-quick calculations. People who excel at mathematics use better strategies than the rest of us; they are not necessarily more intelligent. With Speed Mathematics you'll discover methods to make maths easy and fun. This book is perfect for stud

  18. Lower limb dynamics vary in shod runners who acutely transition to barefoot running.

    Science.gov (United States)

    Hashish, Rami; Samarawickrame, Sachithra D; Powers, Christopher M; Salem, George J

    2016-01-25

    Relative to traditional shod rear-foot strike (RFS) running, habituated barefoot running is associated with a forefoot-strike (FFS) and lower loading rates. Accordingly, barefoot running has been purported to reduce lower-extremity injury risk. Investigations, however, indicate that novice barefoot runners may not innately adopt a FFS. Therefore, the purpose of this study was to examine lower-extremity dynamics of habitually shod runners who acutely transition to barefoot running. 22 recreational RFS runners were included in this investigation. This laboratory controlled study consisted of two visits one-week apart, examining habitually shod, then novice barefoot running. Foot-strike patterns and loading rates were determined using motion analysis and force plates, and joint energy absorption was calculated using inverse dynamics. Of the 22 runners, 8 maintained a RFS, 9 adopted a MFS, and 5 adopted a FFS during novice barefoot running. All runners demonstrated a reduction in knee energy absorption when running barefoot; MFS and FFS runners also demonstrated a significant increase in ankle energy absorption. Runners who maintained a RFS presented with loading rates significantly higher than traditional shoe running, whereas FFS runners demonstrated a significant reduction in loading rate. Mid-foot strikers did not demonstrate a significant change in loading rate. These results indicate that habitually shod RFS runners demonstrate a variety of foot-strike and lower-extremity dynamic responses during the acute transition to barefoot running. Accordingly, explicit instruction regarding foot-strike patterns may be necessary if transitioning to barefoot. Long-term prospective studies are required in order to determine the influence of FFS barefoot running on injury rates. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Increased Vertebral Bone Mineral in Response to Reduced Exercise in Amenorrheic Runners

    OpenAIRE

    Lindberg, Jill S.; Hunt, Marjorie M.; Wade, Charles E.; Powell, Malcolm R.; Ducey, Diane E.

    1987-01-01

    Seven female runners found to have exercise-induced amenorrhea and decreased bone mineral were reevaluated after 15 months. During the 15-month period, four runners took supplemental calcium and reduced their weekly running distance by 43%, resulting in an average 5% increase in body weight, increased estradiol levels and eumenorrhea. Bone mineral content increased from 1.003±0.097 to 1.070±0.089 grams per cm.2 Three runners continued to have amenorrhea, with no change in running distance or ...

  20. Can self-reported BMI be used as a valid measure among novice runners

    DEFF Research Database (Denmark)

    Juul, Martin Serup; Nielsen, R.O.; Rasmussen, Sten

    There is an increased risk of running related injuries (RRI) among novice runners with a Body Mass Index (BMI) above 25. Information about BMI can be collected through questionnaires, when studies investigate if there is an association between BMI and RRI among novice runners. But can self...... of RRI. Healthy novice runners between the age of 18 to 65 and without lower extremity injuries were able to participate in the study. During July and August 2011 the participants were included in the study based on an online questionnaire. 1532 persons completed the questionnaire, of these, 970 were...

  1. Peripheral Neuropathy and Agent Orange

    Science.gov (United States)

    ... Enter ZIP code here Enter ZIP code here Peripheral Neuropathy and Agent Orange VA presumes Veterans' early-onset ... 10 percent disabling by VA's rating regulations. About peripheral neuropathy Peripheral neuropathy is a condition of the peripheral ...

  2. Normative values of eccentric hip abduction strength in novice runners

    DEFF Research Database (Denmark)

    Jørgensen, Daniel Ramskov; Pedersen, Mette Broen; Kastrup, Kristrian

    2014-01-01

    .354) Nm/kg. CONCLUSION: Normative values for maximal eccentric hip abduction strength in novice runners can be calculated by taking into account the differences in strength across genders and the decline in strength that occurs with increasing age. Age and gender were associated with maximal eccentric hip...... associated with maximal eccentric hip abduction strength from a univariate analysis were included in a multivariate linear regression model. Based on the results from the regression model, a regression equation for normative hip abduction strength is presented. RESULTS: A SIGNIFICANT DIFFERENCE IN MAXIMAL...... was found, p gender. Based on this, the equation to calculate normative values for relative eccentric hip abduction strength became: (1.600 + (age * -0.005) + (gender (1 = male / 0 = female) * 0.215) ± 1 or 2 * 0...

  3. Le controfigure di Dio. Da Blade Runner ad Avatar

    Directory of Open Access Journals (Sweden)

    Nicoletta Vallorani

    2011-06-01

    Full Text Available The issue of the relationship between the creator and his/her creature has been often dealt with  in dystopia and science fiction films, and in recent times it has taken on a specific flavor, less related to the implications of science and more connected to a symbolic dimension that goes  back to the Bible as a fruitful reservoir of myths and archetypes. The Biblical parable of the creation  in particular flows into narratives recalling familiar names and places, but deeply revising the  creator/creature relationship, that is unfolded through the poetic unacceptability of death in Blade  Runner (1982 and the possibility of a new life in a new body dwelling in the fictional Eden of Avatar (2010.

  4. Regional economic impacts of Grand Canyon river runners.

    Science.gov (United States)

    Hjerpe, Evan E; Kim, Yeon-Su

    2007-10-01

    Economic impact analysis (EIA) of outdoor recreation can provide critical social information concerning the utilization of natural resources. Outdoor recreation and other non-consumptive uses of resources are viewed as environmentally friendly alternatives to extractive-type industries. While outdoor recreation can be an appropriate use of resources, it generates both beneficial and adverse socioeconomic impacts on rural communities. The authors used EIA to assess the regional economic impacts of rafting in Grand Canyon National Park. The Grand Canyon region of northern Arizona represents a rural US economy that is highly dependent upon tourism and recreational expenditures. The purpose of this research is twofold. The first is to ascertain the previously unknown regional economic impacts of Grand Canyon river runners. The second purpose is to examine attributes of these economic impacts in terms of regional multipliers, leakage, and types of employment created. Most of the literature on economic impacts of outdoor recreation has focused strictly on the positive economic impacts, failing to illuminate the coinciding adverse and constraining economic impacts. Examining the attributes of economic impacts can highlight deficiencies and constraints that limit the economic benefits of recreation and tourism. Regional expenditure information was obtained by surveying non-commercial boaters and commercial outfitters. The authors used IMPLAN input-output modeling to assess direct, indirect, and induced effects of Grand Canyon river runners. Multipliers were calculated for output, employment, and income. Over 22,000 people rafted on the Colorado River through Grand Canyon National Park in 2001, resulting in an estimated $21,100,000 of regional expenditures to the greater Grand Canyon economy. However, over 50% of all rafting-related expenditures were not captured by the regional economy and many of the jobs created by the rafting industry are lower-wage and seasonal. Policy

  5. Eating disorders and health in elite women distance runners.

    Science.gov (United States)

    Hulley, A J; Hill, A J

    2001-11-01

    To examine the presence of eating disorder syndromes in elite women distance runners in the United Kingdom and any associated differences in training, dieting, general health, and well-being. Athletes were selected from the top of their respective ranking lists for all middle and long-distance races in 1996/1997. All running disciplines were included (track, road, cross-country, and fell/mountain running). Athletes were sent the Eating Disorders Examination Questionnaire and a questionnaire on demographics, athletic training, diet, and health. Of the 226 athletes identified, 181 (81%) completed and returned the questionnaires. Twenty-nine athletes (16%) had an eating disorder at the time of the study (7 had anorexia nervosa [AN], 2 had bulimia nervosa [BN], and 20 had eating disorders not otherwise specified [EDNOS]) and a further 6 had received previous treatment. Comparing the eating disorder group with the rest of the sample showed no difference in age, height, preferred race distance, or the number of hours/week spent training. However, they had a significantly lower body mass index (BMI), lower self-esteem, and poorer mental health. Current and past dieting were significantly more common in the eating disorder group. The levels of AN and EDNOS are higher than would be expected in similarly aged, nonathletic women. The demands for leanness rather than exercise intensity appear to be the main risk in these elite runners. The early detection and prevention of eating disorders in women athletes should have high priority. Copyright 2001 by John Wiley & Sons, Inc.

  6. Empirical analysis on the runners' velocity distribution in city marathons

    Science.gov (United States)

    Lin, Zhenquan; Meng, Fan

    2018-01-01

    In recent decades, much researches have been performed on human temporal activity and mobility patterns, while few investigations have been made to examine the features of the velocity distributions of human mobility patterns. In this paper, we investigated empirically the velocity distributions of finishers in New York City marathon, American Chicago marathon, Berlin marathon and London marathon. By statistical analyses on the datasets of the finish time records, we captured some statistical features of human behaviors in marathons: (1) The velocity distributions of all finishers and of partial finishers in the fastest age group both follow log-normal distribution; (2) In the New York City marathon, the velocity distribution of all male runners in eight 5-kilometer internal timing courses undergoes two transitions: from log-normal distribution at the initial stage (several initial courses) to the Gaussian distribution at the middle stage (several middle courses), and to log-normal distribution at the last stage (several last courses); (3) The intensity of the competition, which is described by the root-mean-square value of the rank changes of all runners, goes weaker from initial stage to the middle stage corresponding to the transition of the velocity distribution from log-normal distribution to Gaussian distribution, and when the competition gets stronger in the last course of the middle stage, there will come a transition from Gaussian distribution to log-normal one at last stage. This study may enrich the researches on human mobility patterns and attract attentions on the velocity features of human mobility.

  7. Foot Morphological Difference between Habitually Shod and Unshod Runners.

    Directory of Open Access Journals (Sweden)

    Yang Shu

    Full Text Available Foot morphology and function has received increasing attention from both biomechanics researchers and footwear manufacturers. In this study, 168 habitually unshod runners (90 males whose age, weight & height were 23±2.4 years, 66±7.1 kg & 1.68±0.13 m and 78 females whose age, weight & height were 22±1.8 years, 55±4.7 kg & 1.6±0.11 m (Indians and 196 shod runners (130 males whose age, weight & height were 24±2.6 years, 66±8.2 kg & 1.72±0.18 m and 66 females whose age, weight & height were 23±1.5 years, 54±5.6 kg & 1.62±0.15 m (Chinese participated in a foot scanning test using the easy-foot-scan (a three-dimensional foot scanning system to obtain 3D foot surface data and 2D footprint imaging. Foot length, foot width, hallux angle and minimal distance from hallux to second toe were calculated to analyze foot morphological differences. This study found that significant differences exist between groups (shod Chinese and unshod Indians for foot length (female p = 0.001, width (female p = 0.001, hallux angle (male and female p = 0.001 and the minimal distance (male and female p = 0.001 from hallux to second toe. This study suggests that significant differences in morphology between different ethnicities could be considered for future investigation of locomotion biomechanics characteristics between ethnicities and inform last shape and design so as to reduce injury risks and poor performance from mal-fit shoes.

  8. Differences in kinetic variables between injured and noninjured novice runners : A prospective cohort study

    NARCIS (Netherlands)

    Bredeweg, Steef W.; Kluitenberg, Bas; Bessem, Bram; Buist, Ida

    Objectives: This prospective study examined differences in kinetic variables between injured and noninjured novice female and male runners and their potential contribution to RRIs. Design: A prospective cohort study. Methods: At baseline vertical ground reaction forces were assessed with an

  9. Multiobjective optimal design of runner blade using efficiency and draft tube pulsation criteria

    International Nuclear Information System (INIS)

    Pilev, I M; Sotnikov, A A; Rigin, V E; Semenova, A V; Cherny, S G; Chirkov, D V; Bannikov, D V; Skorospelov, V A

    2012-01-01

    In the present work new criteria of optimal design method for turbine runner [1] are proposed. Firstly, based on the efficient method which couples direct simulation of 3D turbulent flow and engineering semi empirical formulas, the combined method is built for hydraulic energy losses estimation in the whole turbine water passage and the efficiency criterion is formulated. Secondly, the criterion of dynamic loads minimization is developed for those caused by vortex rope precession downstream of the runner. This criterion is based on the finding that the monotonic increase of meridional velocity component in the direction to runner hub, downstream of its blades, provides for decreasing the intensity of vortex rope and thereafter, minimization of pressure pulsation amplitude. The developed algorithm was applied to optimal design of 640 MW Francis turbine runner. It can ensure high efficiency at best efficiency operating point as well as diminished pressure pulsations at full load regime.

  10. Investigation of distributor vane jets to decrease the unsteady load on hydro turbine runner blades

    Science.gov (United States)

    Lewis, B. J.; Cimbala, J. M.; Wouden, A. M.

    2012-11-01

    As the runner blades of a Francis hydroturbine pass though the wakes created from the wicket gates, they experience a significant change in absolute velocity, flow angle, and pressure. The concept of adding jets to the trailing edge of the wicket gates is proposed as a method for reducing the dynamic load on the hydroturbine runner blades. Computational experiments show a decrease in velocity variation experienced by the runner blade with the addition of the jets. The decrease in velocity variation resulted in a 43% decrease in global torque variation at the runner passing frequency. However, an increased variation was observed at the wicket gate passing frequency. Also, a 5.7% increase in average global torque was observed with the addition of blowing from the trailing-edge of the wicket gates.

  11. Investigation of distributor vane jets to decrease the unsteady load on hydro turbine runner blades

    International Nuclear Information System (INIS)

    Lewis, B J; Cimbala, J M; Wouden, A M

    2012-01-01

    As the runner blades of a Francis hydroturbine pass though the wakes created from the wicket gates, they experience a significant change in absolute velocity, flow angle, and pressure. The concept of adding jets to the trailing edge of the wicket gates is proposed as a method for reducing the dynamic load on the hydroturbine runner blades. Computational experiments show a decrease in velocity variation experienced by the runner blade with the addition of the jets. The decrease in velocity variation resulted in a 43% decrease in global torque variation at the runner passing frequency. However, an increased variation was observed at the wicket gate passing frequency. Also, a 5.7% increase in average global torque was observed with the addition of blowing from the trailing-edge of the wicket gates.

  12. Increased vertebral bone mineral in response to reduced exercise in amenorrheic runners.

    Science.gov (United States)

    Lindberg, J S; Powell, M R; Hunt, M M; Ducey, D E; Wade, C E

    1987-01-01

    Seven female runners found to have exercise-induced amenorrhea and decreased bone mineral were reevaluated after 15 months. During the 15-month period, four runners took supplemental calcium and reduced their weekly running distance by 43%, resulting in an average 5% increase in body weight, increased estradiol levels and eumenorrhea. Bone mineral content increased from 1.003+/-0.097 to 1.070+/-0.089 grams per cm.(2) Three runners continued to have amenorrhea, with no change in running distance or body weight. Estradiol levels remained abnormally low and there was no significant change in the bone mineral content, although all three took supplemental calcium. We found that early osteopenia associated with exercise-induced menstrual dysfunction improved when runners reduced their running distance, gained weight and became eumenorrheic.

  13. Vegetative provision of central hemodynamics and physical performance of middle distance sportswomen-runners

    Directory of Open Access Journals (Sweden)

    E. L. Mikhalyuk

    2014-04-01

    Full Text Available Aims. To determine the autonomic provision of the central hemodynamics and physical performance in middle distance sportswomen-runners. Methods and results. A comprehensive survey of 34 sportswomen-sprinters, qualifications from II-III level to the IMS, was carried out. For the analysis of vegetative cardiovascular regulation mathematical methods of HRV were used. In middle distance sportswomen-runners with qualifications of MS-IMS parasympathetic link of autonomic nervous system, hypokinetic types of circulation, large quantities of physical performance and index of functional state prevail compared with sportswomen-runners with qualifications of CMS, I-st, II-nd and III-rd level. Conclusion. Correlation analysis showed a significant interconnection, indicating that the optimal vegetative providing of training process of middle distance runners is accompanied by hypokinetic TC and high digits of PWC170/kg and IFS.

  14. Lower-limb dynamics and clinical outcomes for habitually shod runners who transition to barefoot running.

    Science.gov (United States)

    Hashish, Rami; Samarawickrame, Sachithra D; Sigward, Susan; Azen, Stanley P; Salem, George J

    2018-01-01

    Recent investigations have revealed lower vertical loading rates and knee energy absorption amongst experienced barefoot runners relative to those who rear-foot strike (RFS). Although this has led to an adoption of barefoot running amongst many recreational shoe runners, recent investigations indicate that the experienced barefoot pattern is not immediately realized. Therefore, the purpose this investigation was to quantify changes in lower-extremity dynamics and clinical outcomes measures for habitually shod runners who perform a transition to barefoot running. We examined lower-extremity dynamics and clinical outcomes for 26 RFS shod runners who performed an 8-10 week transition to barefoot running. Runners were evaluated at the University of Southern California's Musculoskeletal Biomechanics Research Laboratory. Foot-strike patterns, vertical load rates, and joint energetics were evaluated before and after the transition using inverse dynamics. Clinical assessments were conducted throughout the transition by two licensed clinicians. Eighteen of the 26 runners successfully completed the transition: 7 maintained a RFS, 8 adopted a mid-foot strike (MFS), and 3 adopted a forefoot strike (FFS) during novice barefoot running. Following the transition, novice MFS/FFS runners often demonstrated reversions in strike-patterns and associated reductions in ankle energetics. We report no change in loading rates and knee energy absorption across transition time points. Importantly, there were no adverse events other than transient pain and soreness. These findings indicate that runners do not innately adopt the biomechanical characteristics thought to lower injury risk in-response to an uninstructed barefoot running transition. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Effect of Jet Shape on Flow and Torque Characteristics of Pelton Turbine Runner

    OpenAIRE

    Vishal Gupta,; Dr. Vishnu Prasad

    2014-01-01

    In Pelton turbine, the energy carried by water is converted into kinetic energy by providing nozzle at the end of penstock. The shape of jet affects the force and torque on the bucket and runner of turbine. The nozzle of circular cross section is commonly used. In this paper attempt has been made to study the effect of four different jet shapes on the flow and torque characteristics of Pelton turbine runner through numerical simulation.

  16. Characteristics of Plantar Pressures and Related Pain Profiles in Elite Sprinters and Recreational Runners.

    Science.gov (United States)

    Chow, Tong-Hsien; Chen, Yih-Shyuan; Wang, Jia-Chang

    2018-01-01

    Plantar pressure measurement is effective for assessing plantar loading and can be applied to evaluating foot performance. We sought to explore the characteristics of plantar pressures in elite sprinters and recreational runners during static standing and walking. Arch index (AI) values, regional plantar pressure distributions (PPDs), and footprint characteristics were examined in 80 elite sprinters and 90 recreational runners using an optical plantar pressure measurement system. Elite sprinters' pain profiles were examined to evaluate their most common pain areas. In recreational runners, AI values in males were in the normal range and in females were high arch type. The AI values were significantly lower in elite sprinters than in recreational runners. In elite sprinters, particularly males, the static PPD of both feet was higher at the medial metatarsal bone and the lateral heel and lower at the medial and lateral longitudinal arches. Elite male sprinters' PPD of both feet was mainly transferred to the medial metatarsal bone and decreased at the lateral longitudinal arch and the medial heel during the midstance phase of walking. The lateral knee joint and biceps femoris were the most common sites of musculoskeletal pain in elite sprinters. Elite sprinters' AI values could be classified as high arches, and their PPD tended to parallel the features of runners and high-arched runners. These findings correspond to the profile of patellofemoral pain syndrome (PFPS)-related plantar pressure. The pain profiles seemed to resonate with the symptoms of high-arched runners and PFPS. A possible link between high-arched runners and PFPS warrants further study.

  17. Racial Discrimination Towards the Hazaras as Reflected in Khaled Hosseini's the Kite Runner

    OpenAIRE

    Handayani, Fadlilah Satya

    2016-01-01

    Khaled Hosseini's novel entitled The Kite Runner is an American bestseller novel that represents racial conflict between the Pashtuns and Hazaras, two different races and ethnics in Afghanistan. The aims of this study are to find out the causes of racial discrimination, to analyze examples of racial discrimination, and to analyze the impacts of racial discrimination as depicted in The Kite Runner. Sociological approach and theories on racism and racial discrimination are used in this study. T...

  18. Vitamin and mineral intake of twelve adolescent male Kalenjin runners in western Kenya

    DEFF Research Database (Denmark)

    Christensen, Dirk Lund; Jakobsen, Jette; Friis, H

    2005-01-01

    runners was carried out to determine their micronutrient intake. MAIN OUTCOME MEASURES: Over a two-week period, samples of the main eaten food were collected for analysis of micronutrient distribution and a daily 24 recall interview performed to determine additional food intake. RESULTS: The estimated...... mg, 1309 microg, and 79 microg, respectively. CONCLUSION: Total daily micronutrient intake of the twelve Kalenjin runners was far from adequate compared to FAO/WHO daily recommended and suggested adequate intake....

  19. Reliability and accuracy of Cooper's test in male long distance runners

    OpenAIRE

    J.R. Alvero-Cruz; M.A. Giráldez García; E.A. Carnero

    2017-01-01

    Objective: Endurance capacity can be assessed by field test such as Cooper's test; however, reliability and accuracy are rarely reported in the literature. It was our aims to describe reliability and accuracy of Cooper's test in long distance runners. Method: Fifteen male long distance runners performed twice all-out Cooper's test in a 400 m track. Total distance covered, maximum heart rate (HR) and rate of perceived exertion were recorded. Bias correction factor (Bc) was used to describe ...

  20. Immediate effects of modified landing pattern on a probabilistic tibial stress fracture model in runners.

    Science.gov (United States)

    Chen, T L; An, W W; Chan, Z Y S; Au, I P H; Zhang, Z H; Cheung, R T H

    2016-03-01

    Tibial stress fracture is a common injury in runners. This condition has been associated with increased impact loading. Since vertical loading rates are related to the landing pattern, many heelstrike runners attempt to modify their footfalls for a lower risk of tibial stress fracture. Such effect of modified landing pattern remains unknown. This study examined the immediate effects of landing pattern modification on the probability of tibial stress fracture. Fourteen experienced heelstrike runners ran on an instrumented treadmill and they were given augmented feedback for landing pattern switch. We measured their running kinematics and kinetics during different landing patterns. Ankle joint contact force and peak tibial strains were estimated using computational models. We used an established mathematical model to determine the effect of landing pattern on stress fracture probability. Heelstrike runners experienced greater impact loading immediately after landing pattern switch (Ptibial strains and the risk of tibial stress fracture in runners with different landing patterns (P>0.986). Immediate transitioning of the landing pattern in heelstrike runners may not offer timely protection against tibial stress fracture, despite a reduction of impact loading. Long-term effects of landing pattern switch remains unknown. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Bridging the gap between metallurgy and fatigue reliability of hydraulic turbine runners

    International Nuclear Information System (INIS)

    Thibault, D; Gagnon, M; Godin, S

    2014-01-01

    The failure of hydraulic turbine runners is a very rare event. Hence, in order to assess the reliability of these components, one cannot rely on statistical models based on the number of failures in a given population. However, as there is a limited number of degradation mechanisms involved, it is possible to use physically-based reliability models. Such models are more complicated but have the advantage of being able to account for physical parameters in the prediction of the evolution of runner degradation. They can therefore propose solutions to help improve reliability. With the use of such models, the effect of materials properties on runner reliability can easily be illustrated. This paper will present a brief review of the Kitagawa-Takahashi diagram that links the damage tolerance approach, based on fracture mechanics, to the stress or strain-life approaches. This diagram is at the centre of the reliability model used in this study. Using simplified response spectra obtained from on-site runner stress measurements, the paper will show how fatigue reliability is impacted by materials fatigue properties, namely fatigue crack propagation behaviour and fatigue limit obtained on S-N curves. It will also present a review of the most important microstructural features of 13%Cr- 4%Ni stainless steels used for runner manufacturing and will review how they influence fatigue properties in an effort to bridge the gap between metallurgy and turbine runners reliability

  2. Half-marathon and full-marathon runners' hydration practices and perceptions.

    Science.gov (United States)

    O'Neal, Eric K; Wingo, Jonathan E; Richardson, Mark T; Leeper, James D; Neggers, Yasmine H; Bishop, Phil A

    2011-01-01

    The behaviors and beliefs of recreational runners with regard to hydration maintenance are not well elucidated. To examine which beverages runners choose to drink and why, negative performance and health experiences related to dehydration, and methods used to assess hydration status. Cross-sectional study. Marathon registration site. Men (n = 146) and women (n = 130) (age = 38.3 ± 11.3 years) registered for the 2010 Little Rock Half-Marathon or Full Marathon. A 23-item questionnaire was administered to runners when they picked up their race timing chips. Runners were separated into tertiles (Low, Mod, High) based on z scores derived from training volume, expected performance, and running experience. We used a 100-mm visual analog scale with anchors of 0 (never) and 100 (always). Total sample responses and comparisons between tertile groups for questionnaire items are presented. The High group (58±31) reported greater consumption of sport beverages in exercise environments than the Low (42 ± 35 mm) and Mod (39 ± 32 mm) groups (P performance during runs greater than 1 hour (P performance decrement, and 45% perceived dehydration to have resulted in adverse health effects. Twenty percent of runners reported monitoring their hydration status. Urine color was the method most often reported (7%), whereas only 2% reported measuring changes in body weight. Greater attention should be paid to informing runners of valid techniques to monitor hydration status and developing an appropriate individualized hydration strategy.

  3. Examining injury risk and pain perception in runners using minimalist footwear.

    Science.gov (United States)

    Ryan, Michael; Elashi, Maha; Newsham-West, Richard; Taunton, Jack

    2014-08-01

    This study examines the effect of progressive increases in footwear minimalism on injury incidence and pain perception in recreational runners. One hundred and three runners with neutral or mild pronation were randomly assigned a neutral (Nike Pegasus 28), partial minimalist (Nike Free 3.0 V2) or full minimalist shoe (Vibram 5-Finger Bikila). Runners underwent baseline testing to record training and injury history, as well as selected anthropometric measurements, before starting a 12-week training programme in preparation for a 10 km event. Outcome measures included number of injury events, Foot and Ankle Disability (FADI) scores and visual analogue scale pain rating scales for regional and overall pain with running. 99 runners were included in final analysis with 23 injuries reported; the neutral shoe reporting the fewest injuries (4) and the partial minimalist shoe (12) the most. The partial minimalist shoe reported a significantly higher rate of injury incidence throughout the 12-week period. Runners in the full minimalist group reported greater shin and calf pain. Running in minimalist footwear appears to increase the likelihood of experiencing an injury, with full minimalist designs specifically increasing pain at the shin and calf. Clinicians should exercise caution when recommending minimalist footwear to runners otherwise new to this footwear category who are preparing for a 10 km event. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  4. Medial tibial stress syndrome in high school cross-country runners: incidence and risk factors.

    Science.gov (United States)

    Plisky, Melody S; Rauh, Mitchell J; Heiderscheit, Bryan; Underwood, Frank B; Tank, Robert T

    2007-02-01

    Prospective cohort. To determine (1) the cumulative seasonal incidence and overall injury rate of medial tibial stress syndrome (MTSS) and (2) risk factors for MTSS with a primary focus on the relationship between navicular drop values and MTSS in high school cross-country runners. MTSS is a common injury among runners. However, few studies have reported the injury rate and risk factors for MTSS among adolescent runners. Data collected included measurement of bilateral navicular drop and foot length, and a baseline questionnaire regarding the runner's height, body mass, previous running injury, running experience, and orthotic or tape use. Runners were followed during the season to determine athletic exposures (AEs) and occurrence of MTSS. The overall injury rate for MTSS was 2.8/1000 AEs. Although not statistically different, girls had a higher rate (4.3/1000 AEs) than boys (1.7/1000 AEs) (P = .11). Logistic regression modeling indicated that only gender and body mass index (BMI) were significantly associated with the occurrence of MTSS. However, when controlled for orthotic use, only BMI was associated with risk of MTSS. No significant associations were found between MTSS and navicular drop or foot length. Our findings suggest that navicular drop may not be an appropriate measure to identify runners who may develop MTSS during a cross-country season; thus, additional studies are needed to identify appropriate preseason screening tools.

  5. [Diseases and overuse injuries of the lower extremities in long distance runners].

    Science.gov (United States)

    Tschopp, M; Brunner, F

    2017-06-01

    Running is one of the most popular sports worldwide, with running events attracting hundreds of thousands of runners of all age groups. Running is an effective way to improve health but is also associated with a high risk of injuries. Up to 50% of regular runners report having more than one injury each year. Some injuries are caused by an accident but most are caused by overuse. The most frequent diagnoses are patellofemoral pain syndrome, tibial stress syndrome (shin splint), Achilles tendinopathy, iliotibial band friction syndrome (runner's knee), plantar fasciitis and stress fractures of the metatarsals and tibia. The knee is the most frequently injured joint in runners at all distances. Hamstring injuries are typically acute resulting in a sudden, sharp pain in the posterior thigh. Hip injuries are less common but it can be more difficult to make the correct diagnosis and treatment is more complex. Clinicians confronted by runners with shin pain must distinguish between stress fractures of the tibia, tibial stress syndrome (shin splints) and chronic exertional compartment syndrome. Foot and ankle injuries are the most common injuries reported by long distance and marathon runners. Excess body weight and the number of kilometers run per week are high risk factors for injuries. The roles of other factors, such as shoes, stretching and biomechanics are less clear. A detailed anamnesis and physical examination are important for the correct diagnosis or the necessity for further diagnostic imaging and subsequent therapy.

  6. Foot strike patterns and collision forces in habitually barefoot versus shod runners.

    Science.gov (United States)

    Lieberman, Daniel E; Venkadesan, Madhusudhan; Werbel, William A; Daoud, Adam I; D'Andrea, Susan; Davis, Irene S; Mang'eni, Robert Ojiambo; Pitsiladis, Yannis

    2010-01-28

    Humans have engaged in endurance running for millions of years, but the modern running shoe was not invented until the 1970s. For most of human evolutionary history, runners were either barefoot or wore minimal footwear such as sandals or moccasins with smaller heels and little cushioning relative to modern running shoes. We wondered how runners coped with the impact caused by the foot colliding with the ground before the invention of the modern shoe. Here we show that habitually barefoot endurance runners often land on the fore-foot (fore-foot strike) before bringing down the heel, but they sometimes land with a flat foot (mid-foot strike) or, less often, on the heel (rear-foot strike). In contrast, habitually shod runners mostly rear-foot strike, facilitated by the elevated and cushioned heel of the modern running shoe. Kinematic and kinetic analyses show that even on hard surfaces, barefoot runners who fore-foot strike generate smaller collision forces than shod rear-foot strikers. This difference results primarily from a more plantarflexed foot at landing and more ankle compliance during impact, decreasing the effective mass of the body that collides with the ground. Fore-foot- and mid-foot-strike gaits were probably more common when humans ran barefoot or in minimal shoes, and may protect the feet and lower limbs from some of the impact-related injuries now experienced by a high percentage of runners.

  7. Barefoot-simulating footwear associated with metatarsal stress injury in 2 runners.

    Science.gov (United States)

    Giuliani, Jeffrey; Masini, Brendan; Alitz, Curtis; Owens, Brett D

    2011-07-07

    Stress-related changes and fractures in the foot are frequent in runners. However, the causative factors, including anatomic and kinematic variables, are not well defined. Footwear choice has also been implicated in contributing to injury patterns with changes in force transmission and gait analyses reported in the biomechanical literature. Despite the benefits of footwear, there has been increased interest among the running community in barefoot running with proposed benefits including a decreased rate of injury. We report 2 cases of metatarsal stress fracture in experienced runners whose only regimen change was the adoption of barefoot-simulating footwear. One was a 19-year-old runner who developed a second metatarsal stress reaction along the entire diaphysis. The second case was a 35-year-old ultra-marathon runner who developed a fracture in the second metatarsal diaphysis after 6 weeks of use of the same footwear. While both stress injuries healed without long-term effects, these injuries are alarming in that they occurred in experienced male runners without any other risk factors for stress injury to bone. The suspected cause for stress injury in these 2 patients is the change to barefoot-simulating footwear. Runners using these shoes should be cautioned on the potential need for gait alterations from a heel-strike to a midfoot-striking pattern, as well as cautioned on the symptoms of stress injury. Copyright 2011, SLACK Incorporated.

  8. Melanoma markers in marathon runners: increase with sun exposure and physical strain.

    Science.gov (United States)

    Richtig, Erika; Ambros-Rudolph, Christina M; Trapp, Michael; Lackner, Helmut K; Hofmann-Wellenhof, Rainer; Kerl, Helmut; Schwaberger, Guenther

    2008-01-01

    Marathon runners seem to have an increased melanoma risk. To identify potential melanoma markers. 150 marathon runners volunteered to take part in the skin cancer screening campaign. After the runners completed a questionnaire about melanoma risk factors, types of sportswear and training programs, they received a total skin examination. The number of lentigines and nevi on the left shoulder and the left buttock were counted in each participant using templates in standardized positions. The potential association of training sportswear and training parameters with the number of lentigines and nevi on the left shoulder was evaluated. The mean number of lentigines on the left shoulder was 19.6 +/- 18.2 (SD), whereas no lentigines were found on the left buttock (p = 0.000). The number of nevi also differed significantly between the 2 localizations with higher numbers on the left shoulder (p = 0.000). While lifetime sunburn history and type of sportswear correlated with the number of lentigines, training parameters had an impact on the number of nevi. Independent of their mean weekly running time, runners with higher heart rates while training, higher training velocities and higher physical strain indexes showed more nevi on the shoulder than the other runners (p = 0.029, 0.046, 0.038, respectively). Sun exposure and high physical strain lead to an increase in melanoma markers such as lentigines and nevi in marathon runners. Copyright 2008 S. Karger AG, Basel.

  9. Pilates training improves 5-km run performance by changing metabolic cost and muscle activity in trained runners

    Science.gov (United States)

    Finatto, Paula; Silva, Edson Soares Da; Okamura, Alexandre B.; Almada, Bruna P.; Oliveira, Henrique B.

    2018-01-01

    Purpose Strength training improves distance running economy and performance. This finding is based predominantly on maximal and explosive strength programmes applied to locomotor muscles, particularly on the lower limbs. It is not certain whether a minimization of metabolic cost (Cmet) and an improvement in running performance is feasible with strength training of the postural and trunk muscles. Methods Using kinematic, neuromuscular and metabolic measurements of running at two different speeds before and after a 12-week Pilates training programme, we tested the hypothesis that core training might improve the running Cmet and performance of trained runners. Thirty-two individuals were randomly assigned to the control group (CG, n = 16) or the Pilates group (PG, n = 16). Results Confirming our hypothesis, a significant improvement (p<0.05) was observed for running performance in the PG (pre: 25.65±0.4 min; post: 23.23±0.4 min) compared to the CG (pre: 25.33±0.58 min; post: 24.61±0.52 min). Similarly, the PG (4.33±0.07 J.kg-1.m-1) had better responses than the CG (4.71±0.11 J.kg-1.m-1) during post-training for Cmet. These findings were accompanied by decreased electromyographic activity of the postural muscles at submaximal running intensities in the PG. Conclusions Overall, these results provide a rationale for selecting strength training strategies that target adaptations on specific postural and locomotor muscles for trained distance runners. PMID:29561907

  10. Pilates training improves 5-km run performance by changing metabolic cost and muscle activity in trained runners.

    Directory of Open Access Journals (Sweden)

    Paula Finatto

    Full Text Available Strength training improves distance running economy and performance. This finding is based predominantly on maximal and explosive strength programmes applied to locomotor muscles, particularly on the lower limbs. It is not certain whether a minimization of metabolic cost (Cmet and an improvement in running performance is feasible with strength training of the postural and trunk muscles.Using kinematic, neuromuscular and metabolic measurements of running at two different speeds before and after a 12-week Pilates training programme, we tested the hypothesis that core training might improve the running Cmet and performance of trained runners. Thirty-two individuals were randomly assigned to the control group (CG, n = 16 or the Pilates group (PG, n = 16.Confirming our hypothesis, a significant improvement (p<0.05 was observed for running performance in the PG (pre: 25.65±0.4 min; post: 23.23±0.4 min compared to the CG (pre: 25.33±0.58 min; post: 24.61±0.52 min. Similarly, the PG (4.33±0.07 J.kg-1.m-1 had better responses than the CG (4.71±0.11 J.kg-1.m-1 during post-training for Cmet. These findings were accompanied by decreased electromyographic activity of the postural muscles at submaximal running intensities in the PG.Overall, these results provide a rationale for selecting strength training strategies that target adaptations on specific postural and locomotor muscles for trained distance runners.

  11. Velocity and pressure measurements in guide vane clearance gap of a low specific speed Francis turbine

    Science.gov (United States)

    Thapa, B. S.; Dahlhaug, O. G.; Thapa, B.

    2016-11-01

    In Francis turbine, a small clearance gap between the guide vanes and the cover plates is usually required to pivot guide vanes as a part of governing system. Deflection of cover plates and erosion of mating surfaces causes this gap to increase from its design value. The clearance gap induces the secondary flow in the distributor system. This effects the main flow at the runner inlet, which causes losses in efficiency and instability. A guide vane cascade of a low specific speed Francis turbine has been developed for experimental investigations. The test setup is able to produce similar velocity distributions at the runner inlet as that of a reference prototype turbine. The setup is designed for particle image velocimetry (PIV) measurements from the position of stay vane outlet to the position of runner inlet. In this study, velocity and pressure measurements are conducted with 2 mm clearance gap on one side of guide vane. Leakage flow is observed and measured together with pressure measurements. It is concluded that the leakage flow behaves as a jet and mixes with the main flow in cross-wise direction and forms a vortex filament. This causes non-uniform inlet flow conditions at runner blades.

  12. Numerical Analysis of Flow in Kaplan Turbine Runner Blades Anticavitation Lip with Modified Hydro-dynamic Profile

    Directory of Open Access Journals (Sweden)

    Vasile Cojocaru

    2011-09-01

    Full Text Available In order to increase the lifetime of runner blades of Kaplan turbines damaged by cavitation erosion, an anticavitation lip is attached to the periphery of the runner blades on the suction side. The anticavitation lip overtakes the cavitation pitting which appears between the runner blades and the runner chamber. A blade with the original anticavitation lip was modeled using CAE. The numerical simulations showed the tip vortex position and the source of the cavitation erosion. Using these data, a modified profile of the anticavitation lip was designed.

  13. Foot strike patterns of recreational and sub-elite runners in a long-distance road race.

    Science.gov (United States)

    Larson, Peter; Higgins, Erin; Kaminski, Justin; Decker, Tamara; Preble, Janine; Lyons, Daniela; McIntyre, Kevin; Normile, Adam

    2011-12-01

    Although the biomechanical properties of the various types of running foot strike (rearfoot, midfoot, and forefoot) have been studied extensively in the laboratory, only a few studies have attempted to quantify the frequency of running foot strike variants among runners in competitive road races. We classified the left and right foot strike patterns of 936 distance runners, most of whom would be considered of recreational or sub-elite ability, at the 10 km point of a half-marathon/marathon road race. We classified 88.9% of runners at the 10 km point as rearfoot strikers, 3.4% as midfoot strikers, 1.8% as forefoot strikers, and 5.9% of runners exhibited discrete foot strike asymmetry. Rearfoot striking was more common among our sample of mostly recreational distance runners than has been previously reported for samples of faster runners. We also compared foot strike patterns of 286 individual marathon runners between the 10 km and 32 km race locations and observed increased frequency of rearfoot striking at 32 km. A large percentage of runners switched from midfoot and forefoot foot strikes at 10 km to rearfoot strikes at 32 km. The frequency of discrete foot strike asymmetry declined from the 10 km to the 32 km location. Among marathon runners, we found no significant relationship between foot strike patterns and race times.

  14. A case study of an iron-deficient female Olympic 1500-m runner.

    Science.gov (United States)

    Pedlar, Charles R; Whyte, Gregory P; Burden, Richard; Moore, Brian; Horgan, Gill; Pollock, Noel

    2013-11-01

    This case study examines the impact of low serum ferritin (sFe) on physiological assessment measures and performance in a young female 1500-m runner undertaking approximately 95-130 km/wk training. The study spans 4 race seasons and an Olympic Games. During this period, 25 venous blood samples were analyzed for sFe and hemoglobin (Hb); running economy, VO(2max), and lactate threshold were measured on 6 occasions separated by 8-10 mo. Training was carefully monitored including 65 monitored treadmill training runs (targeting an intensity associated with the onset of blood lactate accumulation) using blood lactate and heart rate. Performances at competitive track events were recorded. All data were compared longitudinally. Mean sFe was 24.5 ± 7.6 μg/L (range 10-47), appearing to be in gradual decline with the exception of 2 data points (37 and 47 μg/L) after parenteral iron injections before championships, when the lowest values tended to occur, coinciding with peak training volumes. Each season, 1500-m performance improved, from 4:12.8 in year 1 to 4:03.5 in year 4. VO(2max) (69.8 ± 2.0 mL · kg(-1) · min(-1)) and running economy (%VO(2max) at a fixed speed of 16 km/h; max 87.8%, min 80.3%) were stable across time and lactate threshold improved (from 14 to 15.5 km/h). Evidence of anemia (Hb <12 g/dL) was absent. These unique data demonstrate that in 1 endurance athlete, performance can continue to improve despite an apparent iron deficiency. Raising training volume may have caused increased iron utilization; however, the effect of this on performance is unknown. Iron injections were effective in raising sFe in the short term but did not appear to affect the long-term pattern.

  15. Vasculitic peripheral neuropathy

    Directory of Open Access Journals (Sweden)

    Mona Amini

    2014-02-01

    Full Text Available Primary systemic vasculitis in pre-capillary arteries is associated with peripheral neuropathy. In some types of systematic vasculitis about 60 % of patients have peripheral nervous system (PNS involvement. In vasculitic peripheral neuropathies (VPN a necrotizing and inflammatory process leads to narrowing of vasa nervorum lumen and eventually the appearance of ischemic lesions in peripheral nerves. Some features might be suggestive of VPN, like: axonal nerve degeneration, wallerian-like degeneration, and diameter irregularity of nerve. Peripheral nervous system (PNS destruction during systemic vasculitides should be considered, due to its frequency and early occurrence in vasculitis progression. The first line treatment of non systematic VPNs is corticosteroid agents, but these drugs might worsen the VPNs or systemic vasculitis.

  16. Sex differences in association of race performance, skin-fold thicknesses, and training variables for recreational half-marathon runners.

    Science.gov (United States)

    Knechtle, Beat; Knechtle, Patrizia; Rosemann, Thomas; Senn, Oliver

    2010-12-01

    The purpose of this study was to investigate the association between selected skin-fold thicknesses and training variables with a half-marathon race time, for both male and female recreational runners, using bi- and multivariate analysis. In 52 men, two skin-fold thicknesses (abdominal and calf) were significantly and positively correlated with race time; whereas in 15 women, five (pectoral, mid-axilla, subscapular, abdominal, and suprailiac) showed positive and significant relations with total race time. In men, the mean weekly running distance, minimum distance run per week, maximum distance run per week, mean weekly hours of running, number of running training sessions per week, and mean speed of the training sessions were significantly and negatively related to total race time, but not in women. Interaction analyses suggested that race time was more strongly associated with anthropometry in women than men. Race time for the women was independently associated with the sum of eight skin-folds; but for the men, only the mean speed during training sessions was independently associated. Skin-fold thicknesses and training variables in these groups were differently related to race time according to their sex.

  17. Rearfoot and midfoot or forefoot impacts in habitually shod runners.

    Science.gov (United States)

    Boyer, Elizabeth R; Rooney, Brandon D; Derrick, Timothy R

    2014-07-01

    Shear loading rates (LR) have not been investigated in runners with a mid- or forefoot strike (FFS) versus rearfoot strike (RFS). The purpose of this study was to compare three-dimensional ground reaction forces (GRF) and LR during impact in habitual rearfoot strikers (hRF) and habitual forefoot strikers (hFF) strikers. Thirty competitive runners performed 10 overground running trials with both foot strike styles. Peak three-dimensional and resultant GRF and instantaneous LR during impact were compared. Vertical LR significantly decreased for hRF using an FFS (RFS = 148 ± 36 body weight [BW]·s(-1), FFS = 98 ± 31 BW·s(-1)) but was similar for hFF running with either foot strike (FFS = 136 ± 35 BW·s(-1), RFS = 135 ± 28 BW·s(-1)). Posterior impact forces were present during FFS but not during RFS, and posterior LR was significantly greater for both groups during FFS (-58 ± 17 vs -19 ± 6 BW·s(-1)). Medial impact forces were also present during FFS but not during RFS, and medial LR was significantly larger for both groups during FFS (-21 ± 7 vs -6 ± 6 BW·s(-1)). Interestingly, hFF had greater impact peaks and LR in all directions compared with hRF during FFS. This may be explained by hFF using a smaller strike index (hFF = 62% ± 9%, hRF = 67% ± 9%; P = 0.02), which was significantly inversely related to vertical LR and impact peak. Peak resultant and vertical LR are not ubiquitously lower when using a shod FFS versus RFS despite an absence of resultant and vertical impact peaks. Furthermore, there were impact peaks in the posterior and medial directions, leading also to greater LR in these directions during FFS. Therefore, transitioning from RFS to FFS in traditional running shoes may not offer long-term protection against impact-related running injuries because hFF running with an FFS demonstrated many GRF and LR similar to or greater than RFS.

  18. Exercise-induced stress responses of amenorrheic and eumenorrheic runners.

    Science.gov (United States)

    Loucks, A B; Horvath, S M

    1984-12-01

    The role of stress in exercise-associated amenorrhea was investigated. Sex hormones [FSH, LH, androstenedione (A), testosterone, estrone, and 17 beta-estradiol (E2)], stress hormones [dehydroepiandrosterone, cortisol (F), PRL, norepinephrine, and epinephrine] and psychological status (Profile of Mood States and State-Trait Anxiety Inventory) were measured at rest and in response to a 40-min 80% of maximal aerobic power (VO2max) run in highly trained eumenorrheic (n = 8) and amenorrheic (n = 7) women runners matched for fatness [eumenorrheic, 16.5 +/- 2.3% (+/- SD); amenorrheic, 14.9 +/- 4.8] and maximal aerobic power (eumenorrheic, 58.9 +/- 5.7 ml/kg X min; amenorrheic, 59.8 +/- 4.6). Eumenorrheic runners were tested between days 3 and 8 of the follicular phase. At rest, decreased plasma FSH, LH, and E2 concentrations were found in amenorrheic women [eumenorrheic FSH, 10.5 +/- 4.1 mIU/ml; amenorrheic FSH, 4.9 +/- 1.6 (P less than 0.01); eumenorrheic LH, 14.1 +/- 6.1 mIU/ml; amenorrheic LH, 5.1 +/- 1.7 (P less than 0.01); eumenorrheic E2, 20 +/- 9 pg/ml; amenorrheic E2, 7 +/- 6 (P less than 0.05)]. Other sex and stress hormones and psychological measurements were similar in the two groups and were within the normal range. Ventilatory, cardiovascular, thermoregulatory, and psychological responses to the submaximal run were identical. Among eumenorrheic women, all stress hormones and A increased after exercise, but PRL, F, and A were unchanged among amenorrheic women. Estrone, E2, and testosterone did not change in either group. These observations are inconsistent with a general stress hypothesis of exercise-associated amenorrhea as well as with more specific hyperprolactinemic and hyperandrogenic hypotheses. In amenorrheic women, failure of PRL to increase in response to exercise may be due to their lack of E2, while failure of F and A to increase may indicate reduced adrenal 3 beta-hydroxysteroid dehydrogenase/isomerase activity.

  19. Prevalence of allergy and upper respiratory tract symptoms in runners of the London marathon.

    Science.gov (United States)

    Robson-Ansley, Paula; Howatson, Glyn; Tallent, Jamie; Mitcheson, Kelly; Walshe, Ian; Toms, Chris; DU Toit, George; Smith, Matt; Ansley, Les

    2012-06-01

    The prevalence of self-reported upper respiratory tract (URT) symptoms in athletes has been traditionally associated with opportunistic infection during the temporal suppression of immune function after prolonged exercise. There is little evidence for this, and a competing noninfectious hypothesis has been proposed, whereby the exercise-induced immune system modulations favor the development of atopy and allergic disease, which manifests as URT symptoms. The aim of this study was to examine the association between allergy and URT symptoms in runners after an endurance running event. Two hundred eight runners from the 2010 London Marathon completed the validated Allergy Questionnaire for Athletes (AQUA) and had serum analyzed for total and specific immunoglobulin E response to common inhalant allergens. Participants who completed the marathon and nonrunning controls who lived in the same household were asked to complete a diary on URT symptoms. Forty percent of runners had allergy as defined by both a positive AQUA and elevated specific immunoglobulin E. Forty-seven percent of runners experienced URT symptoms after the marathon. A positive AQUA was a significant predictor of postmarathon URT symptoms in runners. Only 19% of nonrunning controls reported symptoms. The prevalence of allergy in recreational marathon runners was similar to that in elite athletes and higher than that in the general population. There was a strong association between a positive AQUA and URT symptoms. The low proportion of households in which both runners and nonrunners were symptomatic suggests that the nature of symptoms may be allergic or inflammatory based rather than infectious. Allergy is a treatable condition, and its potential effect on performance and health may be avoided by accurate clinical diagnosis and management. Both athletes' and coaches' awareness of the potential implications of poorly managed allergy needs to be raised.

  20. Exaggerated gonadotropin response to luteinizing hormone-releasing hormone in amenorrheic runners.

    Science.gov (United States)

    Yahiro, J; Glass, A R; Fears, W B; Ferguson, E W; Vigersky, R A

    1987-03-01

    Most studies of exercise-induced amenorrhea have compared amenorrheic athletes (usually runners) with sedentary control subjects. Such comparisons will identify hormonal changes that develop as a result of exercise training but cannot determine which of these changes play a role in causing amenorrhea. To obviate this problem, we assessed reproductive hormone status in a group of five amenorrheic runners and compared them to a group of six eumenorrheic runners matched for body fatness, training intensity, and exercise performance. Compared to the eumenorrheic runners, the amenorrheic runners had lower serum estradiol concentrations, similar basal serum luteinizing hormone and follicle-stimulating hormone concentrations, and exaggerated responses of serum gonadotropins after administration of luteinizing hormone-releasing hormone (100 micrograms intravenous bolus). Serum prolactin levels, both basally and after thyrotropin-releasing hormone administration (500 micrograms intravenous bolus) or treadmill exercise, was similar in the two groups, as were serum thyroid function tests (including thyrotropin response to thyrotropin-releasing hormone). Changes in serum cortisol levels after short-term treadmill exercise were similar in both groups, and serum testosterone levels increased after exercise only in the eumenorrheic group. In neither group did such exercise change serum luteinizing hormone, follicle-stimulating hormone, or thyrotropin levels. We concluded that exercise-induced amenorrhea is not solely related to the development of increased prolactin output after exercise training. The exaggerated gonadotropin response to luteinizing hormone-releasing hormone seen in amenorrheic runners in comparison with matched eumenorrheic runners is consistent with a hypothalamic etiology for the menstrual dysfunction, analogous to that previously described in "stress-induced" or "psychogenic" amenorrhea.

  1. Metallurgical and fatigue assessments of welds in cast welded hydraulic turbine runners

    International Nuclear Information System (INIS)

    Trudel, A; Sabourin, M

    2014-01-01

    Decades of hydraulic turbine operation around the world have shown one undeniable fact; welded turbine runners can be prone to fatigue cracking, especially in the vicinity of welds. In this regard, three factors are essential to consider in runner fatigue assessments: (1) the runner's design, which can induce stress concentrations in the fillets, (2) the casting process, which inherently creates defects such as shrinkage cavities and (3) the welding process, which induces significant residual stresses as well as a heat affected zone in the cast pieces near the interface with the filler metal. This study focuses on the latter, the welding process, with emphasis on the influence of the heat affected zone on the runner's fatigue behavior. In a recently concluded study by a large research consortium in Montreal, the microstructure and fatigue crack propagation properties of a CA6NM runner weld heat affected zone were thoroughly investigated to find if this zone deteriorates the runner's resistance to fatigue cracking. The main results showed that this zone's intrinsic fatigue crack propagation resistance is only slightly lower than the unaffected base metal because of its somewhat finer martensitic microstructure leading to a less tortuous crack path. However, it was also confirmed that weld-induced residual stresses represent the dominant influencing factor regarding fatigue crack propagation, though post-weld heat treatments are usually very effective in reducing such residual stresses. This paper aims to further confirm, through a case study, that the weld-induced heat affected zone does not compromise the reliability of welded turbine runners when its fatigue crack propagation properties are considered in fatigue damage models

  2. Donating Peripheral Blood Stem Cells

    Science.gov (United States)

    ... Print this page My Cart Donating peripheral blood stem cells Peripheral blood stem cell (PBSC) donation is a nonsurgical procedure to collect ... Donating bone marrow Donor experiences videos Peripheral blood stem cell (PBSC) donation is one of two methods of ...

  3. Peripheral Neuropathy: Symptoms and Signs

    Science.gov (United States)

    ... Utah Research News Make a Difference Symptoms of Peripheral Neuropathy Print This Page Peripheral Neuropathy symptoms usually start ... more slowly over many years. The symptoms of peripheral neuropathy often include: A sensation of wearing an invisible “ ...

  4. Athletic Engagement and Athletic Identity in Top Croatian Sprint Runners.

    Science.gov (United States)

    Babić, Vesna; Sarac, Jelena; Missoni, Sasa; Sindik, Josko

    2015-09-01

    The aim of the research was to determine construct validity and reliability for two questionnaires (Athlete Engagement Questionnaire-AEQ and Athletic Identity Measurement Scale-AIMS), applied on elite Croatian athletes-sprinters, as well as the correlations among the dimensions in these measuring instruments. Then, we have determined the differences in the dimensions of sport engagement and sport identity, according to gender, education level and winning medals on international competitions. A total of 71 elite athletes-sprinters (former and still active) are examined, from which 27 (38%) females and 44 (62%) males. The results of factor analyses revealed the existence of dimensions very similar as in the original instruments, which showed moderate to-high reliabilities. A small number of statistically significant correlations have been found between the dimensions of sport engagement and sport identity, mainly in male sprinter runners. Small number of statistically significant differences in the dimensions of sport engagement and sport identity have been found according to the gender, education level and winning medals on the international competitions. The most reasonable explanation of these differences could be given in terms of very similar characteristics of elite athletes on the same level of sport excellence.

  5. Bilateral femoral supracondylar stress fractures in a cross country runner.

    Science.gov (United States)

    Ross, Kate; Fahey, Mark

    2008-08-01

    Several high-risk factors lead to stress fractures. They include excessive training in athletes leading to overuse injuries, nutritional deficiencies, and endocrine disorders. While stress fractures are common, bilateral stress fractures are rarely seen. Few cases have been reported of bilateral femoral stress fractures in young athletes. This article presents a case of a 14-year-old cross country runner with a bilateral femoral supracondylar stress fracture. He presented with bilateral supracondylar stress fractures from running. The patient followed a strict vegan diet, but his parents stated that, to their knowledge, he was getting adequate protein and calcium. Treatment consisted of decreased activity to pain-free levels with acetaminophen for pain. Low-impact conditioning such as swimming and bicycling was allowed. Hamstring and quadricep stretching was suggested. Nutritional consultation was obtained to ensure appropriate nutrition on a vegan diet. At 1-month follow-up, he was pain free and allowed to proceed with a gradual return to running activities. In this case, the onset of a new workout routine was intolerable for this patient's low bone density, causing insufficiency fractures. Appropriate vegan diets were not associated with stress fracture in our literature review. He may have had an inadequate diet prior to this injury. As in this case, full recovery can be made after this rest period, and the patient may return to his or her original activity safely. In young athletes, diet and nutrition must be kept in mind.

  6. What do recreational runners think about risk factors for running injuries? A descriptive study of their beliefs and opinions.

    Science.gov (United States)

    Saragiotto, Bruno Tirotti; Yamato, Tiê Parma; Lopes, Alexandre Dias

    2014-10-01

    Qualitative study based on semi-structured interviews. To describe the beliefs and opinions of runners about risk factors associated with running injuries. Despite the health benefits of running, a high prevalence of injury has been reported in runners. Preventive strategies for running injuries may be more successful with a better knowledge of runners' beliefs. A semi-structured interview of recreational runners was based on the question, "What do you think can cause injuries in runners?" Analysis of the interviews was performed in 3 steps: (1) organizing the data into thematic units, (2) reading and reorganizing the data according to frequency of citation, and (3) interpreting and summarizing the data. The runner interviews were continued until no new beliefs and opinions of runners regarding injuries were being added to the data, indicating saturation of the topic. A total of 95 recreational runners (65 men, 30 women) between the ages of 19 and 71 years were interviewed. Of those interviewed, the average running experience was 5.5 years and approximately 45% had experienced a running-related injury in the past. The factors suggested by the runners were divided into extrinsic and intrinsic factors. The most cited extrinsic factors were "not stretching," "excess of training," "not warming up," "lack of strength," and "wearing the wrong shoes." For the intrinsic factors, the main terms cited were "not respecting the body's limitations" and "foot-type changes." Recreational runners mainly attributed injury to factors related to training, running shoes, and exceeding the body's limits. Knowing the factors identified in this study may contribute to the development of better educational strategies to prevent running injuries, as some of the runners' beliefs are not supported by the research literature.

  7. Influence of the rotor-stator interaction on the dynamic stresses of Francis runners

    International Nuclear Information System (INIS)

    Guillaume, R; Scolaro, D; Deniau, J L; Colombet, C

    2012-01-01

    Thanks to advances in computing capabilities and Computational Fluid Dynamics (CFD) techniques, it is now possible to calculate realistic unsteady pressure fields in Francis turbines. This paper will explain methods to calculate the structural loads and the dynamic behaviour in order to optimize the turbine design and maximize its reliability and lifetime. Depending on the operating conditions of a Francis turbine, different hydraulic phenomena may impact the mechanical behaviour of the structure. According to their nature, these highly variable phenomena should be treated differently and specifically in order to estimate the potential risks arising on submerged structures, in particular the runner. The operating condition studied thereafter is the point at maximum power with the maximum head. Under this condition, the runner is excited by only one dynamic phenomenon named the Rotor-Stator Interaction (RSI). The origin of the phenomenon is located on the radial gap of the turbine and is the source of pressure fluctuations. A fluid-structure analysis is performed to observe the influence of that dynamic pressure field on the runner behaviour. The first part of the paper deals with the unsteady fluid computation. The RSI phenomenon is totally unsteady so the fluid simulation must take into account the entire machine and its rotation movement, in order to obtain a dynamic pressure field. In the second part of the paper, a method suitable for the RSI study is developed. It is known that the fluctuating pressure in this gap can be described as a sum of spatial components. By evaluating these components in the CFD results and on the scale model, it is possible to assess the relevance of the numerical results on the whole runner. After this step, the numerical pressure field can be used as the dynamic load of the structure. The final part of the paper presentsthe mechanical finite element calculations. A modal analysis of the runner in water and a harmonic analysis of its

  8. Development of a pump-turbine runner based on multiobjective optimization

    International Nuclear Information System (INIS)

    Xuhe, W; Baoshan, Z; Lei, T; Jie, Z; Shuliang, C

    2014-01-01

    As a key component of reversible pump-turbine unit, pump-turbine runner rotates at pump or turbine direction according to the demand of power grid, so higher efficiencies under both operating modes have great importance for energy saving. In the present paper, a multiobjective optimization design strategy, which includes 3D inverse design method, CFD calculations, response surface method (RSM) and multiobjective genetic algorithm (MOGA), is introduced to develop a model pump-turbine runner for middle-high head pumped storage plant. Parameters that controlling blade shape, such as blade loading and blade lean angle at high pressure side are chosen as input parameters, while runner efficiencies under both pump and turbine modes are selected as objective functions. In order to validate the availability of the optimization design system, one runner configuration from Pareto front is manufactured for experimental research. Test results show that the highest unit efficiency is 91.0% under turbine mode and 90.8% under pump mode for the designed runner, of which prototype efficiencies are 93.88% and 93.27% respectively. Viscous CFD calculations for full passage model are also conducted, which aim at finding out the hydraulic improvement from internal flow analyses

  9. Transient myocardial tissue and function changes during a marathon in less fit marathon runners.

    Science.gov (United States)

    Gaudreault, Valerie; Tizon-Marcos, Helena; Poirier, Paul; Pibarot, Philippe; Gilbert, Philippe; Amyot, Marc; Rodés-Cabau, Josep; Després, Jean-Pierre; Bertrand, Olivier; Larose, Eric

    2013-10-01

    Although regular physical activity improves health, strenuous exercise might transiently increase cardiac risk. Training and fitness might provide protection. We prospectively studied 20 recreational marathon runners without known cardiovascular disease or symptoms: at peak training before, immediately after, and 3 months after a 42.2-km marathon. Changes in global/segmental myocardial function, edema, resting perfusion, and fibrosis were measured. At peak training, runners exercised 8.1 ± 2.3 hours and 62 ± 18 km per week with mean maximal oxygen consumption (VO2max) of 53.2 ± 8.3 mL/kg/min. In response to the marathon, global left ventricular and right ventricular ejection fraction decreased in half of the runners; these runners had poorer peak training distance, training time, and fitness level. Change in global left ventricular ejection fraction was associated with VO2max. Overall, 36% of segments developed edema, 53% decreased function, and 59% decreased perfusion. Significant agreement was observed between segment decreasing function, decreasing perfusion, and developing edema. Myocardial changes were reversible at 3 months. Completing a marathon leads to localized myocardial edema, diminished perfusion, and decreased function occurring more extensively in less trained and fit runners. Although reversible, these changes might contribute to the transient increase in cardiac risk reported during sustained vigorous exercise. Copyright © 2013 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

  10. Load variation effects on the pressure fluctuations exerted on a Kaplan turbine runner

    International Nuclear Information System (INIS)

    Amiri, K; Cervantes, M J; Mulu, B; Raisee, M

    2014-01-01

    Introduction of intermittent electricity production systems like wind power and solar systems to electricity market together with the consumption-based electricity production resulted in numerous start/stops, load variations and off-design operation of water turbines. The hydropower systems suffer from the varying loads exerted on the stationary and rotating parts of the turbines during load variations which they are not designed for. On the other hand, investigations on part load operation of single regulated turbines, i.e., Francis and propeller, proved the formation of rotating vortex rope (RVR) in the draft tube. The RVR induces oscillating flow both in plunging and rotating modes which results in oscillating force with two different frequencies on the runner blades, bearings and other rotating parts of the turbine. The purpose of this study is to investigate the effect of transient operations on the pressure fluctuations on the runner and mechanism of the RVR formation/mitigation. Draft tube and runner blades of the Porjus U9 model, a Kaplan turbine, were equipped with pressure sensors. The model was run in off-cam mode during different load variation conditions to check the runner performance under unsteady condition. The results showed that the transients between the best efficiency point and the high load happens in a smooth way while transitions to/from the part load, where rotating vortex rope (RVR) forms in the draft tube induces high level of fluctuations with two frequencies on the runner; plunging and rotating mode of the RVR

  11. Load variation effects on the pressure fluctuations exerted on a Kaplan turbine runner

    Science.gov (United States)

    Amiri, K.; Mulu, B.; Raisee, M.; Cervantes, M. J.

    2014-03-01

    Introduction of intermittent electricity production systems like wind power and solar systems to electricity market together with the consumption-based electricity production resulted in numerous start/stops, load variations and off-design operation of water turbines. The hydropower systems suffer from the varying loads exerted on the stationary and rotating parts of the turbines during load variations which they are not designed for. On the other hand, investigations on part load operation of single regulated turbines, i.e., Francis and propeller, proved the formation of rotating vortex rope (RVR) in the draft tube. The RVR induces oscillating flow both in plunging and rotating modes which results in oscillating force with two different frequencies on the runner blades, bearings and other rotating parts of the turbine. The purpose of this study is to investigate the effect of transient operations on the pressure fluctuations on the runner and mechanism of the RVR formation/mitigation. Draft tube and runner blades of the Porjus U9 model, a Kaplan turbine, were equipped with pressure sensors. The model was run in off-cam mode during different load variation conditions to check the runner performance under unsteady condition. The results showed that the transients between the best efficiency point and the high load happens in a smooth way while transitions to/from the part load, where rotating vortex rope (RVR) forms in the draft tube induces high level of fluctuations with two frequencies on the runner; plunging and rotating mode of the RVR.

  12. Foot strike and injury rates in endurance runners: a retrospective study.

    Science.gov (United States)

    Daoud, Adam I; Geissler, Gary J; Wang, Frank; Saretsky, Jason; Daoud, Yahya A; Lieberman, Daniel E

    2012-07-01

    This retrospective study tests if runners who habitually forefoot strike have different rates of injury than runners who habitually rearfoot strike. We measured the strike characteristics of middle- and long-distance runners from a collegiate cross-country team and quantified their history of injury, including the incidence and rate of specific injuries, the severity of each injury, and the rate of mild, moderate, and severe injuries per mile run. Of the 52 runners studied, 36 (69%) primarily used a rearfoot strike and 16 (31%) primarily used a forefoot strike. Approximately 74% of runners experienced a moderate or severe injury each year, but those who habitually rearfoot strike had approximately twice the rate of repetitive stress injuries than individuals who habitually forefoot strike. Traumatic injury rates were not significantly different between the two groups. A generalized linear model showed that strike type, sex, race distance, and average miles per week each correlate significantly (P strike have significantly higher rates of repetitive stress injury than those who mostly forefoot strike. This study does not test the causal bases for this general difference. One hypothesis, which requires further research, is that the absence of a marked impact peak in the ground reaction force during a forefoot strike compared with a rearfoot strike may contribute to lower rates of injuries in habitual forefoot strikers.

  13. Isokinetic analysis of ankle and ground reaction forces in runners and triathletes

    Directory of Open Access Journals (Sweden)

    Natália Mariana Silva Luna

    2012-09-01

    Full Text Available OBJECTIVE: To analyze and compare the vertical component of ground reaction forces and isokinetic muscle parameters for plantar flexion and dorsiflexion of the ankle between long-distance runners, triathletes, and nonathletes. METHODS: Seventy-five males with a mean age of 30.26 (±6.5 years were divided into three groups: a triathlete group (n=26, a long-distance runner group (n = 23, and a non-athlete control group. The kinetic parameters were measured during running using a force platform, and the isokinetic parameters were measured using an isokinetic dynamometer. RESULTS: The non-athlete control group and the triathlete group exhibited smaller vertical forces, a greater ground contact time, and a greater application of force during maximum vertical acceleration than the long-distance runner group. The total work (180º/s was greater in eccentric dorsiflexion and concentric plantar flexion for the non-athlete control group and the triathlete group than the long-distance runner group. The peak torque (60º/s was greater in eccentric plantar flexion and concentric dorsiflexion for the control group than the athlete groups. CONCLUSIONS: The athlete groups exhibited less muscle strength and resistance than the control group, and the triathletes exhibited less impact and better endurance performance than the runners.

  14. COMPARATIVE KINEMATIC MEASURES OF TREADMILL RUNNING WITH OR WITHOUT BODY WEIGHT SUPPORT IN RUNNERS

    Directory of Open Access Journals (Sweden)

    Duane Millslagle

    2005-12-01

    Full Text Available Treadmill walking and running using a supportive harness has been used as a training method to rehabilitate injured patients' walking or running gait. Comparison of full weight support (FWS and body weight support (BWS kinematic measures in competitive runners has received little attention. The purpose of this study was to compare selected FWS to BWS kinematic measures in healthy competitive runners. Ten male runners (age = 21.4 ± 1.5 years with a training regimen averaging 64 km per week at 3.8 m·s-1 participated. All participants ran three 3-minute trials. The randomized trial conditions were: FWS, 20% BWS, and 40% BWS. All conditions were videotaped with 2 cameras and a 21-point, 3-D model was generated for analysis. From the position-time data, cycle length (CL, cycle frequency (CF, time of contact (TC, hip-, knee-, ankle- range of motion in degrees (H-ROM, K-ROM, and A-ROM, respectively, and vertical displacement of the center of mass (COM were derived and compared. With increasing support conditions, cycle length increased. Cycle frequency, hip and ankle angle ranges, and COM vertical displacement decreased (p 0.05. BWS running produced significant changes in selected kinematic measures. These changes may provide insight into runners' behavior when using BWS in training or recovery from competition. Additional investigation of BWS training affect with competitive runners would be recommended

  15. Microclimate Variation and Estimated Heat Stress of Runners in the 2020 Tokyo Olympic Marathon

    Directory of Open Access Journals (Sweden)

    Eichi Kosaka

    2018-05-01

    Full Text Available The Tokyo 2020 Olympic Games will be held in July and August. As these are the hottest months in Tokyo, the risk of heat stress to athletes and spectators in outdoor sporting events is a serious concern. This study focuses on the marathon races, which are held outside for a prolonged time, and evaluates the potential heat stress of marathon runners using the COMFA (COMfort FormulA Human Heat Balance (HBB Model. The study applies a four-step procedure: (a measure the thermal environment along the marathon course; (b estimate heat stress on runners by applying COMFA; (c identify locations where runners may be exposed to extreme heat stress; and (d discuss measures to mitigate the heat stress on runners. On clear sunny days, the entire course is rated as ‘dangerous’ or ‘extremely dangerous’, and within the latter half of the course, there is a 10-km portion where values continuously exceed the extremely dangerous level. Findings illustrate which stretches have the highest need for mitigation measures, such as starting the race one hour earlier, allowing runners to run in the shade of buildings or making use of urban greenery including expanding the tree canopy.

  16. Running speed during training and percent body fat predict race time in recreational male marathoners.

    Science.gov (United States)

    Barandun, Ursula; Knechtle, Beat; Knechtle, Patrizia; Klipstein, Andreas; Rüst, Christoph Alexander; Rosemann, Thomas; Lepers, Romuald

    2012-01-01

    Recent studies have shown that personal best marathon time is a strong predictor of race time in male ultramarathoners. We aimed to determine variables predictive of marathon race time in recreational male marathoners by using the same characteristics of anthropometry and training as used for ultramarathoners. Anthropometric and training characteristics of 126 recreational male marathoners were bivariately and multivariately related to marathon race times. After multivariate regression, running speed of the training units (β = -0.52, P marathon race times. Marathon race time for recreational male runners may be estimated to some extent by using the following equation (r (2) = 0.44): race time ( minutes) = 326.3 + 2.394 × (percent body fat, %) - 12.06 × (speed in training, km/hours). Running speed during training sessions correlated with prerace percent body fat (r = 0.33, P = 0.0002). The model including anthropometric and training variables explained 44% of the variance of marathon race times, whereas running speed during training sessions alone explained 40%. Thus, training speed was more predictive of marathon performance times than anthropometric characteristics. The present results suggest that low body fat and running speed during training close to race pace (about 11 km/hour) are two key factors for a fast marathon race time in recreational male marathoner runners.

  17. Peripheral Ulcerative Keratitis

    Science.gov (United States)

    ... oval in shape. Diagnosis A doctor's evaluation Sometimes culture The diagnosis of peripheral ulcerative keratitis is suspected when the doctor sees the affected cornea in a person who also has a severe and/or long- ...

  18. Tumors of peripheral nerves

    International Nuclear Information System (INIS)

    Ho, Michael; Lutz, Amelie M.

    2017-01-01

    Differentiation between malignant and benign tumors of peripheral nerves in the early stages is challenging; however, due to the unfavorable prognosis of malignant tumors early identification is required. To show the possibilities for detection, differential diagnosis and clinical management of peripheral nerve tumors by imaging appearance in magnetic resonance (MR) neurography. Review of current literature available in PubMed and MEDLINE, supplemented by the authors' own observations in clinical practice. Although not pathognomonic, several imaging features have been reported for a differentiation between distinct peripheral nerve tumors. The use of MR neurography enables detection and initial differential diagnosis in tumors of peripheral nerves. Furthermore, it plays an important role in clinical follow-up, targeted biopsy and surgical planning. (orig.) [de

  19. Promoting peripheral myelin repair

    OpenAIRE

    Zhou, Ye; Notterpek, Lucia

    2016-01-01

    Compared to the central nervous system (CNS), peripheral nerves have a remarkable ability to regenerate and remyelinate. This regenerative capacity to a large extent is dependent on and supported by Schwann cells, the myelin-forming glial cells of the peripheral nervous system (PNS). In a variety of paradigms, Schwann cells are critical in the removal of the degenerated tissue, which is followed by remyelination of newly-regenerated axons. This unique plasticity of Schwann cells has been the ...

  20. 76 FR 68057 - Importation of French Beans and Runner Beans From the Republic of Kenya Into the United States

    Science.gov (United States)

    2011-11-03

    .... APHIS-2010-0101] RIN 0579-AD39 Importation of French Beans and Runner Beans From the Republic of Kenya.... SUMMARY: We are amending the fruits and vegetables regulations to allow the importation of French beans and runner beans from the Republic of Kenya into the United States. As a condition of entry, both...

  1. How does high-intensity intermittent training affect recreational endurance runners? Acute and chronic adaptations: A systematic review

    Directory of Open Access Journals (Sweden)

    Felipe García-Pinillos

    2017-03-01

    Conclusion: HIIT-based running plans (2 to 3 HIIT sessions per week, combining HIIT and CR runs show athletic performance improvements in endurance runners by improving maximal oxygen uptake and running economy along with muscular and metabolic adaptations. To maximize the adaptations to training, both HIIT and CR must be part of training programs for endurance runners.

  2. No effect of a graded training program on the number of running-related injuries in novice runners

    NARCIS (Netherlands)

    Buist, Ida; Bredeweg, Steef W.; van Mechelen, Willem; Lemmink, Koen A. P. M.; Pepping, Gert-Jan; Diercks, Ron L.

    Background: Although running has positive effects on health and fitness, the incidence of a running-related injury (RRI) is high. Research on prevention of RRI is scarce; to date, no studies have involved novice runners. Hypothesis: A graded training program for novice runners will lead to a

  3. The effectiveness of a preconditioning programme on preventing running-related injuries in novice runners : a randomised controlled trial

    NARCIS (Netherlands)

    Bredeweg, Steef W.; Zijlstra, Sjouke; Bessem, Bram; Buist, Ida

    Objectives There is no consensus on the aetiology and prevention of running-related injuries in runners. Preconditioning studies among different athlete populations show positive effects on the incidence of sports injuries. Hypothesis A 4-week preconditioning programme in novice runners will reduce

  4. Food and macronutrient intake of male adolescent Kalenjin runners in Kenya

    DEFF Research Database (Denmark)

    Christensen, Dirk L; Van Hall, Gerrit; Hambraeus, Leif

    2002-01-01

    A nutritional survey based on twelve adolescent male Kalenjin runners in Kenya during a 2-week field study was carried out in order to determine the composition of their diet and make a comparison with macronutrient recommendations for athletes. Food samples were collected for analysis of macronu......A nutritional survey based on twelve adolescent male Kalenjin runners in Kenya during a 2-week field study was carried out in order to determine the composition of their diet and make a comparison with macronutrient recommendations for athletes. Food samples were collected for analysis...... of macronutrient distribution and energy content from main meals and the macronutrient distribution and energy content of additional food intake were based on the information of a 24 h recall interview and estimated from food tables. The diet of the Kalenjin runners was very high in carbohydrate (71 % 8.7 g...

  5. Does running with or without changes in diet reduce fat mass in novice runners?

    DEFF Research Database (Denmark)

    Nielsen, Rasmus O.; Videbæk, Solvej; Hansen, Mette

    2016-01-01

    BACKGROUND: The aim of this study was to explore how average weekly running distance, combined with changes in diet habits and reasons to take up running, influence fat mass. METHODS: Fat mass was assessed by bioelectrical impedance at baseline and after 12 months in 538 novice runners included...... in a 1-year observational prospective follow-up study. During follow-up, running distance for each participant was continuously measured by GPS while reasons to take up running and diet changes were assessed trough web-based questionnaires. Loss of fat mass was compared between runners covering...... an average of 5 km or more per week and those running shorter distances. RESULTS: Runners who took up running to lose weight and ran over 5 km per week in average over a one-year period combined with a diet change reduced fat mass by -5.58 kg (95% CI: -8.69; -2.46; P

  6. Differences in ground contact time explain the less efficient running economy in north african runners.

    Science.gov (United States)

    Santos-Concejero, J; Granados, C; Irazusta, J; Bidaurrazaga-Letona, I; Zabala-Lili, J; Tam, N; Gil, S M

    2013-09-01

    The purpose of this study was to investigate the relationship between biomechanical variables and running economy in North African and European runners. Eight North African and 13 European male runners of the same athletic level ran 4-minute stages on a treadmill at varying set velocities. During the test, biomechanical variables such as ground contact time, swing time, stride length, stride frequency, stride angle and the different sub-phases of ground contact were recorded using an optical measurement system. Additionally, oxygen uptake was measured to calculate running economy. The European runners were more economical than the North African runners at 19.5 km · h(-1), presented lower ground contact time at 18 km · h(-1) and 19.5 km · h(-1) and experienced later propulsion sub-phase at 10.5 km · h(-1),12 km · h(-1), 15 km · h(-1), 16.5 km · h(-1) and 19.5 km · h(-1) than the European runners (P Running economy at 19.5 km · h(-1) was negatively correlated with swing time (r = -0.53) and stride angle (r = -0.52), whereas it was positively correlated with ground contact time (r = 0.53). Within the constraints of extrapolating these findings, the less efficient running economy in North African runners may imply that their outstanding performance at international athletic events appears not to be linked to running efficiency. Further, the differences in metabolic demand seem to be associated with differing biomechanical characteristics during ground contact, including longer contact times.

  7. Unsteady flow simulations of Pelton turbine at different rotational speeds

    Directory of Open Access Journals (Sweden)

    Minsuk Choi

    2015-11-01

    Full Text Available This article presents numerical simulations of a small Pelton turbine suitable for desalination system. A commercial flow solver was adopted to resolve difficulties in the numerical simulation for Pelton turbine such as the relative motion of the turbine runner to the injector and two-phase flow of water and air. To decrease the numerical diffusion of the water jet, a new topology with only hexagonal mesh was suggested for the computational mesh around the complex geometry of a bucket. The predicted flow coefficient, net head coefficient, and overall efficiency showed a good agreement with the experimental data. Based on the validation of the numerical results, the pattern of wet area on the bucket inner surface has been analyzed at different rotational speeds, and an attempt to find the connection between rotational speeds, torque, and efficiency has been made.

  8. Integrity and life estimation of turbine runner cover in a hydro power plant

    Directory of Open Access Journals (Sweden)

    A. Sedmak

    2016-03-01

    Full Text Available This paper presents integrity and life estimation of turbine runner cover in a vertical pipe turbines, Kaplan 200 MW nominal output power, produced in Russia, and built in six hydro-generation units of hydroelectric power plant „Đerdap 1” in Serbia. Fatigue and corrosion-fatigue interaction have been taken into account using experimentally obtained material properties, as well as analytical and numerical calculations of stress state, to estimate appropriate safety factors. Fatigue crack growth rate, da/dN, was also calculated, indicated that internal defects of circular or elliptical shape, found out by ultrasonic testing, do not affect reliable operation of runner cover.

  9. Mathematical, numerical and experimental analysis of the swirling flow at a Kaplan runner outlet

    Science.gov (United States)

    Muntean, S.; Ciocan, T.; Susan-Resiga, R. F.; Cervantes, M.; Nilsson, H.

    2012-11-01

    The paper presents a novel mathematical model for a-priori computation of the swirling flow at Kaplan runners outlet. The model is an extension of the initial version developed by Susan-Resiga et al [1], to include the contributions of non-negligible radial velocity and of the variable rothalpy. Simple analytical expressions are derived for these additional data from three-dimensional numerical simulations of the Kaplan turbine. The final results, i.e. velocity components profiles, are validated against experimental data at two operating points, with the same Kaplan runner blades opening, but variable discharge.

  10. The effect of shoe type on gait in forefoot strike runners during a 50-km run

    Directory of Open Access Journals (Sweden)

    Mark E. Kasmer

    2014-06-01

    Conclusion: More runners adopted a more posterior initial contact area after the 50-km run in the traditional shoe type than in the minimalist shoe type. The runners who adopted a more posterior initial contact area were more closely associated with an increased median frequency of the medial gastrocnemius, which suggests there may be a change in motor unit recruitment pattern during long-distance, sustained velocity running. The increased peak pressures observed in the medial forefoot in the minimalist shoe type may predispose to metatarsal stress fractures in the setting of improper training.

  11. Mathematical, numerical and experimental analysis of the swirling flow at a Kaplan runner outlet

    International Nuclear Information System (INIS)

    Muntean, S; Ciocan, T; Susan-Resiga, R F; Cervantes, M; Nilsson, H

    2012-01-01

    The paper presents a novel mathematical model for a-priori computation of the swirling flow at Kaplan runners outlet. The model is an extension of the initial version developed by Susan-Resiga et al [1], to include the contributions of non-negligible radial velocity and of the variable rothalpy. Simple analytical expressions are derived for these additional data from three-dimensional numerical simulations of the Kaplan turbine. The final results, i.e. velocity components profiles, are validated against experimental data at two operating points, with the same Kaplan runner blades opening, but variable discharge.

  12. Bilateral Anterior Knee Pain in a High School Cross-Country Runner: An Atypical Etiology.

    Science.gov (United States)

    MacDonald, James

    2017-09-01

    Anterior knee pain is a common complaint found in distance runners, and can be the end result of a variety of benign processes. A 17-year-old female cross-country runner presented to a sports medicine clinic with insidious onset of bilateral patellofemoral pain (PFP). In the workup of the significant quadriceps weakness discovered on her initial examination, a principal contributing cause of her PFP, she was found to have a form of spinal muscular atrophy, an uncommon neurodegenerative disease that typically requires multidisciplinary medical care. Her case provides a good example for clinicians to consider, at times, an in-depth assessment of the root causes of benign conditions.

  13. Lower extremity biomechanical relationships with different speeds in traditional, minimalist, and barefoot footwear.

    Science.gov (United States)

    Fredericks, William; Swank, Seth; Teisberg, Madeline; Hampton, Bethany; Ridpath, Lance; Hanna, Jandy B

    2015-06-01

    Minimalist running footwear has grown increasingly popular. Prior studies that have compared lower extremity biomechanics in minimalist running to traditional running conditions are largely limited to a single running velocity. This study compares the effects of running at various speeds on foot strike pattern, stride length, knee angles and ankle angles in traditional, barefoot, and minimalist running conditions. Twenty-six recreational runners (19-46 years of age) ran on a treadmill at a range of speeds (2.5-4.0 m·sec(-1)). Subjects ran with four different footwear conditions: personal, standard, and minimalist shoes and barefoot. 3D coordinates from video data were collected. The relationships between speed, knee and ankle angles at foot strike and toe-off, relative step length, and footwear conditions were evaluated by ANCOVA, with speed as the co-variate. Distribution of non-rearfoot strike was compared across shod conditions with paired t-tests. Non-rearfoot strike distribution was not significantly affected by speed, but was different between shod conditions (p strike. When controlling for foot strike style, barefoot and minimalist runners exhibited greater plantarflexion than other conditions (p strike pattern. Additionally, speed and footwear predict ankle angles (greater plantarflexion at foot strike) and may have implications for minimalist runners and their risk of injury. Long-term studies utilizing various speeds and habituation times are needed. Key pointsFoot strike style does not change with speed, but does change with shod condition, with minimalist shoes exhibiting an intermediate distribution of forefoot strikes between barefoot and traditional shoes.Plantarflexion at touchdown does change with speed and with shoe type, with barefoot and minimalist shoes exhibiting a greater plantarflexion angle than traditional running shoes.Knee angles change with speed in all shod conditions, but knee flexion at touchdown is not different between shod

  14. Prevalence in running events and running performance of endurance runners following a vegetarian or vegan diet compared to non-vegetarian endurance runners: the NURMI Study

    OpenAIRE

    Wirnitzer, Katharina; Seyfart, Tom; Leitzmann, Claus; Keller, Markus; Wirnitzer, Gerold; Lechleitner, Christoph; Rüst, Christoph Alexander; Rosemann, Thomas; Knechtle, Beat

    2016-01-01

    BACKGROUND: Beneficial and detrimental effects of various vegetarian and vegan diets on the health status are well known. Considering the growing background numbers of vegetarians and vegans, the number of vegetarian and vegan runners is likely to rise, too. Therefore, the Nutrition and Running High Mileage (NURMI) Study was designed as a comparative study to investigate the prevalence of omnivores, vegetarians, and vegans in running events and to detect potential differences in running perfo...

  15. Prevalence in running events and running performance of endurance runners following a vegetarian or vegan diet compared to non-vegetarian endurance runners: the NURMI Study.

    Science.gov (United States)

    Wirnitzer, Katharina; Seyfart, Tom; Leitzmann, Claus; Keller, Markus; Wirnitzer, Gerold; Lechleitner, Christoph; Rüst, Christoph Alexander; Rosemann, Thomas; Knechtle, Beat

    2016-01-01

    Beneficial and detrimental effects of various vegetarian and vegan diets on the health status are well known. Considering the growing background numbers of vegetarians and vegans, the number of vegetarian and vegan runners is likely to rise, too. Therefore, the Nutrition and Running High Mileage (NURMI) Study was designed as a comparative study to investigate the prevalence of omnivores, vegetarians, and vegans in running events and to detect potential differences in running performance comparing these three subgroups. The NURMI Study will be conducted in three steps following a cross-sectional design. Step 1 will determine epidemiological aspects of endurance runners (any distance) using a short standardized questionnaire. Step 2 will investigate dietary habits and running history from eligible participants (capable of running a half-marathon at least) using an extended standardized questionnaire. Step 3 will collect data after a running event on finishing time and final ranking as well as a post-race rating of perceived exertion, mood status, nutrient and fluid intake during the race. Our study will provide a major contribution to overcome the lack of data on the prevalence and running performance of vegetarian and vegan runners in endurance running events. We estimate the prevalence of vegetarians and vegans participating in a running event to be less compared to the respective proportion of vegetarians and vegans to the general population. Furthermore we will validate the subject's self-assessment of their respective diet. This comparative study may identify possible effects of dietary behavior on running performance und may detect possible differences between the respective subgroups: omnivorous, vegetarian and vegan runners. Trial registration Current controlled trials, ISRCTN73074080.

  16. The effect of moderate running on foot posture index and plantar pressure distribution in male recreational runners.

    Science.gov (United States)

    Escamilla-Martínez, Elena; Martínez-Nova, Alfonso; Gómez-Martín, Beatriz; Sánchez-Rodríguez, Raquel; Fernández-Seguín, Lourdes María

    2013-01-01

    Fatigue due to running has been shown to contribute to changes in plantar pressure distribution. However, little is known about changes in foot posture after running. We sought to compare the foot posture index before and after moderate exercise and to relate any changes to plantar pressure patterns. A baropodometric evaluation was made, using the FootScan platform (RSscan International, Olen, Belgium), of 30 men who were regular runners and their foot posture was examined using the Foot Posture Index before and after a 60-min continuous run at a moderate pace (3.3 m/sec). Foot posture showed a tendency toward pronation after the 60-min run, gaining 2 points in the foot posture index. The total support and medial heel contact areas increased, as did pressures under the second metatarsal head and medial heel. Continuous running at a moderate speed (3.3 m/sec) induced changes in heel strike related to enhanced pronation posture, indicative of greater stress on that zone after physical activity. This observation may help us understand the functioning of the foot, prevent injuries, and design effective plantar orthoses in sport.

  17. Product-related top runner approach at EU level; Grundkonzeption eines produktbezogenen Top-Runner-Modells auf der EU-Ebene

    Energy Technology Data Exchange (ETDEWEB)

    Jepsen, Dirk; Reintjes, Norbert [Institut fuer Oekologie und Politik GmbH (OEKOPOL), Hamburg (Germany); Rubik, Frieder; Stecker, Rebecca; Engel, Florian; Eisenhauer, Patrik [Institut fuer Oekologische Wirtschaftsforschung (IOEW) gGmbH, Berlin (Germany); Schomerus, Thomas; Spengler, Laura [Leuphana Univ., Lueneburg (Germany)

    2011-06-15

    This publication shows that the environmental ministers of the EU member states are largely agreed that a new generation of green legislation with dynamic standards is needed in order to create strong incentives for resource-efficient innovation. The German Federal Government has recognised the potential of this approach and is making a political drive for the introduction of a top-runner promotion scheme at EU level. A scheme of the same kind has also been incorporated in Germany's energy efficiency action plan. The top runner promotion scheme is a system of requirements and incentives for the promotion of the best and most efficient products on the market. It can also serve as a guiding model for product-related environmental protection in Germany. In its general considerations of the interaction between community law and national law in the implementation of the top runner promotion scheme on the basis of the Ecodesign Directive and in a special analysis based on the example of boilers and small-scale firing installations the present study shows that there is a trend of steady curtailment of the legislator's scope of influence. If any national scope for product-related regulation does still exist, then only in niches, but not in a manner that would permit the legal implementation of broad concepts.

  18. Peripheral epithelial odontogenic tumor

    International Nuclear Information System (INIS)

    Carzoglio, J.; Tancredi, N.; Capurro, S.; Ravecca, T.; Scarrone, P.

    2006-01-01

    A new case of peripheral epithelial odontogenic tumor (Pindborg tumor) is reported. It is localized in the superior right gingival region, a less frequent site, and has the histopathological features previously reported. Immunochemical studies were performed, revealing a differential positive stain to cytokeratins in tumor cells deeply seated in the tumor mass, probably related to tumoral cell heterogeneity.Interestingly, in this particular case S-100 protein positive reactivity was also detected in arborescent cells intermingled with tumoral cells, resembling Langerhans cells. Even though referred in the literature in central Pindborg tumors, no references were found about their presence in peripheral tumors, like the one that is presented here

  19. Vitamin D status and biomarkers of inflammation in runners

    Directory of Open Access Journals (Sweden)

    Willis KS

    2012-04-01

    Full Text Available Kentz S Willis1, Derek T Smith2, Kenneth S Broughton3, D Enette Larson-Meyer2,31Extension, 2Division of Kinesiology and Health, 3Department of Family and Consumer Sciences (Human Nutrition, University of Wyoming, Laramie, WY, USABackground and purpose: The extra-skeletal functions of vitamin D – including its role in inflammatory modulation – are now well recognized but have not yet been investigated in an athletic population. Thus, the purpose of this study was to investigate the relationship between vitamin D status and pro- and anti-inflammatory cytokines (as markers of inflammation and immune system function in endurance athletes.Patients and methods: We analyzed fasting blood samples from 19 healthy, endurance-trained male and female runners (following a standardized diet and exercise regimen for vitamin D status (serum 25-hydroxyvitamin D [25(OHD] and specific plasma cytokine concentrations (tumor necrosis factor alpha [TNF-α], interferon-gamma [IFN-γ], interleukin [IL]-4, and IL-10. Serum/plasma concentrations were log-transformed and simple regression analysis was used to determine significant associations between 25(OHD and cytokine concentrations.Results: Forty-two percent of participants had insufficient vitamin D status [25(OHD < 32 ng/mL], whereas 11% were deficient [25(OHD , 20 ng/mL]. TNF-α and IL-4 were variable, ranging from 2.9 to 36.4 pg/mL and 0 to 252.1 pg/mL, respectively. Concentrations of IFN-γ and IL-10 were minimal, with means of 6.7 ± 7.0 pg/mL and 4.8 ± 5.1 pg/mL, respectively. Regression analysis revealed a significant inverse association between 25(OHD and TNF-α concentrations (R2 = 56.5, P < 0.001 but not between 25(OHD and the remaining cytokines, IFN-γ, IL-4, and IL-10 (P = 0.477, 0.694, and 0.673, respectively.Conclusion: These results call further attention to the epidemic of vitamin D insufficiency, even in outdoor athletes, and support a possible link between decreased vitamin D status and one

  20. The efficacy of downhill running as a method to enhance running economy in trained distance runners.

    Science.gov (United States)

    Shaw, Andrew J; Ingham, Stephen A; Folland, Jonathan P

    2018-06-01

    Running downhill, in comparison to running on the flat, appears to involve an exaggerated stretch-shortening cycle (SSC) due to greater impact loads and higher vertical velocity on landing, whilst also incurring a lower metabolic cost. Therefore, downhill running could facilitate higher volumes of training at higher speeds whilst performing an exaggerated SSC, potentially inducing favourable adaptations in running mechanics and running economy (RE). This investigation assessed the efficacy of a supplementary 8-week programme of downhill running as a means of enhancing RE in well-trained distance runners. Nineteen athletes completed supplementary downhill (-5% gradient; n = 10) or flat (n = 9) run training twice a week for 8 weeks within their habitual training. Participants trained at a standardised intensity based on the velocity of lactate turnpoint (vLTP), with training volume increased incrementally between weeks. Changes in energy cost of running (E C ) and vLTP were assessed on both flat and downhill gradients, in addition to maximal oxygen uptake (⩒O 2max). No changes in E C were observed during flat running following downhill (1.22 ± 0.09 vs 1.20 ± 0.07 Kcal kg -1  km -1 , P = .41) or flat run training (1.21 ± 0.13 vs 1.19 ± 0.12 Kcal kg -1  km -1 ). Moreover, no changes in E C during downhill running were observed in either condition (P > .23). vLTP increased following both downhill (16.5 ± 0.7 vs 16.9 ± 0.6 km h -1 , P = .05) and flat run training (16.9 ± 0.7 vs 17.2 ± 1.0 km h -1 , P = .05), though no differences in responses were observed between groups (P = .53). Therefore, a short programme of supplementary downhill run training does not appear to enhance RE in already well-trained individuals.

  1. Effect of fatigue and gender on kinematics and ground reaction forces variables in recreational runners.

    Science.gov (United States)

    Bazuelo-Ruiz, Bruno; Durá-Gil, Juan V; Palomares, Nicolás; Medina, Enrique; Llana-Belloch, Salvador

    2018-01-01

    The presence of fatigue has been shown to modify running biomechanics. Overall in terms of gender, women are at lower risk than men for sustaining running-related injuries, although it depends on the factors taken into account. One possible reason for these differences in the injury rate and location might be the dissimilar running patterns between men and women. The purpose of this study was to determine the effect of fatigue and gender on the kinematic and ground reaction forces (GRF) parameters in recreational runners. Fifty-seven participants (28 males and 29 females) had kinematic and GRF variables measured while running at speed of 3.3 m s -1 before and after a fatigue test protocol. The fatigue protocol included (1) a running Course-Navette test, (2) running up and down a flight of stairs for 5 min, and (3) performance of alternating jumps on a step (five sets of 1 minute each with 30 resting seconds between the sets). Fatigue decreased dorsiflexion (14.24 ± 4.98° in pre-fatigue and 12.65 ± 6.21° in fatigue condition, p  < 0.05) at foot strike phase in females, and plantar flexion (-19.23 ± 4.12° in pre-fatigue and -18.26 ± 5.31° in fatigue condition, p  < 0.05) at toe-off phase in males. These changes led to a decreased loading rate (88.14 ± 25.82 BW/s in pre-fatigue and 83.97 ± 18.83 BW/s in fatigue condition, p  < 0.05) and the impact peak in females (1.95 ± 0.31 BW in pre-fatigue and 1.90 ± 0.31 BW in fatigue condition, p  < 0.05), and higher peak propulsive forces in males (-0.26 ± 0.04 BW in pre-fatigue and -0.27 ± 0.05 BW in fatigue condition, p  < 0.05) in the fatigue condition. It seems that better responses to impact under a fatigue condition are observed among women. Further studies should confirm whether these changes represent a strategy to optimize shock attenuation, prevent running injuries and improve running economy.

  2. Effect of fatigue and gender on kinematics and ground reaction forces variables in recreational runners

    Directory of Open Access Journals (Sweden)

    Bruno Bazuelo-Ruiz

    2018-03-01

    Full Text Available The presence of fatigue has been shown to modify running biomechanics. Overall in terms of gender, women are at lower risk than men for sustaining running-related injuries, although it depends on the factors taken into account. One possible reason for these differences in the injury rate and location might be the dissimilar running patterns between men and women. The purpose of this study was to determine the effect of fatigue and gender on the kinematic and ground reaction forces (GRF parameters in recreational runners. Fifty-seven participants (28 males and 29 females had kinematic and GRF variables measured while running at speed of 3.3 m s−1 before and after a fatigue test protocol. The fatigue protocol included (1 a running Course-Navette test, (2 running up and down a flight of stairs for 5 min, and (3 performance of alternating jumps on a step (five sets of 1 minute each with 30 resting seconds between the sets. Fatigue decreased dorsiflexion (14.24 ± 4.98° in pre-fatigue and 12.65 ± 6.21° in fatigue condition, p < 0.05 at foot strike phase in females, and plantar flexion (−19.23 ± 4.12° in pre-fatigue and −18.26 ± 5.31° in fatigue condition, p < 0.05 at toe-off phase in males. These changes led to a decreased loading rate (88.14 ± 25.82 BW/s in pre-fatigue and 83.97 ± 18.83 BW/s in fatigue condition, p < 0.05 and the impact peak in females (1.95 ± 0.31 BW in pre-fatigue and 1.90 ± 0.31 BW in fatigue condition, p < 0.05, and higher peak propulsive forces in males (−0.26 ± 0.04 BW in pre-fatigue and −0.27 ± 0.05 BW in fatigue condition, p < 0.05 in the fatigue condition. It seems that better responses to impact under a fatigue condition are observed among women. Further studies should confirm whether these changes represent a strategy to optimize shock attenuation, prevent running injuries and improve running economy.

  3. A method to combine hydrodynamics and constructive design in the optimization of the runner blades of Kaplan turbines

    International Nuclear Information System (INIS)

    Miclosina, C O; Balint, D I; Campian, C V; Frunzaverde, D; Ion, I

    2012-01-01

    This paper deals with the optimization of the axial hydraulic turbines of Kaplan type. The optimization of the runner blade is presented systematically from two points of view: hydrodynamic and constructive. Combining these aspects in order to gain a safer operation when unsteady effects occur in the runner of the turbine is attempted. The design and optimization of the runner blade is performed with QTurbo3D software developed at the Center for Research in Hydraulics, Automation and Thermal Processes (CCHAPT) from 'Eftimie Murgu' University of Resita, Romania. QTurbo3D software offers possibilities to design the meridian channel of hydraulic turbines design the blades and optimize the runner blade. 3D modeling and motion analysis of the runner blade operating mechanism are accomplished using SolidWorks software. The purpose of motion study is to obtain forces, torques or stresses in the runner blade operating mechanism, necessary to estimate its lifetime. This paper clearly states the importance of combining the hydrodynamics with the structural design in the optimization procedure of the runner of hydraulic turbines.

  4. A method to combine hydrodynamics and constructive design in the optimization of the runner blades of Kaplan turbines

    Science.gov (United States)

    Miclosina, C. O.; Balint, D. I.; Campian, C. V.; Frunzaverde, D.; Ion, I.

    2012-11-01

    This paper deals with the optimization of the axial hydraulic turbines of Kaplan type. The optimization of the runner blade is presented systematically from two points of view: hydrodynamic and constructive. Combining these aspects in order to gain a safer operation when unsteady effects occur in the runner of the turbine is attempted. The design and optimization of the runner blade is performed with QTurbo3D software developed at the Center for Research in Hydraulics, Automation and Thermal Processes (CCHAPT) from "Eftimie Murgu" University of Resita, Romania. QTurbo3D software offers possibilities to design the meridian channel of hydraulic turbines design the blades and optimize the runner blade. 3D modeling and motion analysis of the runner blade operating mechanism are accomplished using SolidWorks software. The purpose of motion study is to obtain forces, torques or stresses in the runner blade operating mechanism, necessary to estimate its lifetime. This paper clearly states the importance of combining the hydrodynamics with the structural design in the optimization procedure of the runner of hydraulic turbines.

  5. Speeds in school zones.

    Science.gov (United States)

    2009-02-01

    School speed zones are frequently requested traffic controls for school areas, based on the common belief : that if the transportation agency would only install a reduced speed limit, then drivers would no longer : speed through the area. This resear...

  6. Influence of Sahour Meal on Exercise Performance and Physiological Responses in Well-trained Muslim Runners during Ramadan

    Directory of Open Access Journals (Sweden)

    Goh Kok Wei

    2013-07-01

    Full Text Available Introduction: The objective of this study was to examine the influence of sahour meal on exercise performance, and physiological responses to a 10Km Time-Trial (10KTT at two different times of the day during Ramadan. Method: Three well-trained Muslim runners participated (age, 25±0.8years; maximal oxygen uptake, 54.87±3.45 ml.kg-1.min-1; body weight, 52.4±1.99 kg; height, 162.7±3.55 cm. Subjects ran a 10KTT on four occasions: 8.00am (Am, and 5.00pm (Pm, separated by one day rest two weeks before Ramadan (BRam and during the second week of Ramadan (DRam. BRam, subjects consumed their usual diet. DRam, subjects consumed a standardized sahour meal containing 15.6±0.6kcal/kgBW; 2.3±0.1gCHO/kgBW; 0.6±0.0g Protein/kgBW; 0.5±0.0gFat/kgBW. During each 10KTT, the subject ran at 85%VO2max for the first two Km, and then at a self-selected speed then onwards. Blood samples were collected before the run, and at 2, and the end of 10 Km. Time to complete 10KTT were recorded. Urine specific gravity was measured before each run. Results: There was no difference in hydration status for the Am and Pm runs BRam and DRam. Running performance DRamAM, was better compared to the DRamPm. There were also no changes in blood glucose BRam and DRam. Serum Testosterone was highest at the end of 10KTT DRamPm when compared to the DRamAm, and was generally higher than BRam. Serum Cortisol showed no differences between the trials. All runners did not experience dehydration, lack of energy nor drop in performance DRam. Conclusion: The results from this study suggest that when athletes are provided with a balanced sahour meal, during Ramadan, they can maintain their performance.

  7. Influence of Sahour meal on exercise performance and physiological responses in well-trained Muslim runners during Ramadan

    Directory of Open Access Journals (Sweden)

    Goh Kok Wei

    2013-03-01

    Full Text Available Introduction: The objective of this study was to examine the influence of sahour meal on exercise performance, and physiological responses to a 10Km Time-Trial (10KTT at two different times of the day during Ramadan. Method: Three well-trained Muslim runners participated (age, 25±0.8years; maximal oxygen uptake, 54.87±3.45 ml.kg-1.min-1; body weight, 52.4±1.99 kg; height, 162.7±3.55 cm.  Subjects ran a 10KTT on four occasions: 8.00am (Am, and 5.00pm (Pm, separated by one day rest two weeks before Ramadan (BRam and during the second week of Ramadan (DRam. BRam, subjects consumed their usual diet. DRam, subjects consumed a standardized sahour meal containing 15.6±0.6kcal/kgBW; 2.3±0.1gCHO/kgBW; 0.6±0.0g Protein/kgBW; 0.5±0.0gFat/kgBW. During each 10KTT, the subject ran at 85%VO2max for the first two Km, and then at a self-selected speed then onwards. Blood samples were collected before the run, and at 2, and the end of 10 Km. Time to complete 10KTT were recorded. Urine specific gravity was measured before each run. Results: There was no difference in hydration status for the Am and Pm runs BRam and DRam. Running performance DRamAM, was better compared to the DRamPm. There were also no changes in blood glucose BRam and DRam. Serum Testosterone was highest at the end of 10KTT DRamPm when compared to the DRamAm, and was generally higher than BRam. Serum Cortisol showed no differences between the trials. All runners did not experience dehydration, lack of energy nor drop in performance DRam. Conclusion: The results from this study suggest that when athletes are provided with a balanced sahour meal, during Ramadan, they can maintain their performance.

  8. The Relationship between Running Economy and Biomechanical Variables in Distance Runners

    Science.gov (United States)

    Tartaruga, Marcus Peikriszwili; Brisswalter, Jeanick; Peyre-Tartaruga, Leonardo Alexandre; Avila, Aluisio Otavio Vargas; Alberton, Cristine Lima; Coertjens, Marcelo; Cadore, Eduardo Lusa; Tiggemann, Carlos Leandro; Silva, Eduardo Marczwski; Kruel, Luiz Fernando Martins

    2012-01-01

    In this study, we analyzed the relationship between running economy (RE) and biomechanical parameters in a group running at the same relative intensity and same absolute velocity. Sixteen homogeneous male long-distance runners performed a test to determine RE at 4.4 m.s[superscript -1], corresponding to 11.1% below velocity at the ventilatory…

  9. 7 CFR 51.2710 - U.S. No. 1 Runner.

    Science.gov (United States)

    2010-01-01

    ... Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946... of shelled Runner type peanut kernels of similar varietal characteristics which are whole and free...

  10. 7 CFR 51.2712 - U.S. No. 2 Runner.

    Science.gov (United States)

    2010-01-01

    ... Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946... of shelled Runner type peanut kernels of similar varietal characteristics which may be split or...

  11. Effect of a Marathon Run on Serum Lipoproteins, Creatine Kinase, and Lactate Dehydrogenase in Recreational Runners

    Science.gov (United States)

    Kobayashi, Yoshio; Takeuchi, Toshiko; Hosoi, Teruo; Yoshizaki, Hidekiyo; Loeppky, Jack A.

    2005-01-01

    The objective of this study was to determine the effect of a marathon run on serum lipid and lipoprotein concentrations and serum muscle enzyme activities and follow their recovery after the run. These blood concentrations were measured before, immediately after, and serially after a marathon run in 15 male recreational runners. The triglyceride…

  12. The impact of injury definition on injury surveillance in novice runners

    NARCIS (Netherlands)

    Kluitenberg, Bas; van Middelkoop, Marienke; Verhagen, Evert; Hartgens, Fred; Huisstede, Bionka; Diercks, Ron; van der Worp, Henk

    Objectives: Despite several consensus statements, different injury definitions are used in the literature. This study aimed to identify the impact of different injury definitions on the nature and incidence of complaints captured during a short-term running program for novice runners. Design:

  13. The diagnosis of stress fractures of runners by an isotope scintigraphy

    International Nuclear Information System (INIS)

    Karvonen, J.; Nieminen, M.

    1988-01-01

    By means of isotope scintigraphy the suspected stress fractures in the lower limb bones of ten competitive runners were verified in nine cases (9/10). In all cases the X-rays were normal. By conservative treatment avoiding excessive stress, the intensive local isotope uptake in the bone and pain symptoms of the stress fracture disappeared after 2-4 months. (orig.)

  14. MR imaging of the knee in marathon runners before and after competition

    International Nuclear Information System (INIS)

    Krampla, W.; Mayrhofer, R.; Malcher, J.; Urban, M.; Hruby, W.; Kristen, K.H.

    2001-01-01

    Objective. To evaluate the findings in MRI-studies of the knee in recreational long-distance runners after competition and to assess the reversibility of the findings.Design and patients. Eight recreational long-distance runners underwent MRI studies of the knee before, immediately after and 6-8 weeks after taking part in the Vienna City Marathon. The studies were evaluated regarding alterations of pre-existing lesions and new pathological findings.Results. In six runners without major pre-existing alterations no negative effects were experienced. In one runner with pre-existing grade III alterations of the menisci, signs of progressive osteoarthritis were experienced 2 months after the competition. In all other cases increased meniscal signal alterations and minor signal changes in the bone marrow after the race were transitory.Conclusion. In healthy individuals no negative long-term-effects were experienced. Pre-existing high-grade lesions of the menisci might be a predisposing risk for osteoarthritis, triggered by the stress of long-distance running. (orig.)

  15. Hydraulic design and optimization of a modular pump-turbine runner

    International Nuclear Information System (INIS)

    Schleicher, W.C.; Oztekin, A.

    2015-01-01

    Highlights: • A modular pumped-storage scheme using elevated water storage towers is investigated. • The pumped-storage scheme also aides in the wastewater treatment process. • A preliminary hydraulic pump-turbine runner design is created based on existing literature. • The preliminary design is optimized using a response surface optimization methodology. • The performance and flow fields between preliminary and optimized designs are compared. - Abstract: A novel modular pumped-storage scheme is investigated that uses elevated water storage towers and cement pools as the upper and lower reservoirs. The scheme serves a second purpose as part of the wastewater treatment process, providing multiple benefits besides energy storage. A small pumped-storage scheme has been shown to be a competitive energy storage solution for micro renewable energy grids; however, pumped-storage schemes have not been implemented on scales smaller than megawatts. Off-the-shelf runner designs are not available for modular pumped-storage schemes, so a custom runner design is sought. A preliminary hydraulic design for a pump-turbine runner is examined and optimized for increased pumping hydraulic efficiency using a response surface optimization methodology. The hydraulic pumping efficiency was found to have improved by 1.06% at the best efficiency point, while turbine hydraulic efficiency decreased by 0.70% at the turbine best efficiency point. The round-trip efficiency for the system was estimated to be about 78%, which is comparable to larger pumped-storage schemes currently in operation

  16. Relationship between Achilles tendon properties and foot strike patterns in long-distance runners.

    Science.gov (United States)

    Kubo, Keitaro; Miyazaki, Daisuke; Tanaka, Shigeharu; Shimoju, Shozo; Tsunoda, Naoya

    2015-01-01

    The purpose of this study was to investigate the relationship between Achilles tendon properties and foot strike patterns in long-distance runners. Forty-one highly trained male long-distance runners participated in this study. Elongation of the Achilles tendon and aponeurosis of the medial gastrocnemius muscle were measured using ultrasonography, while the participants performed ramp isometric plantar flexion up to the voluntary maximum. The relationship between the estimated muscle force and tendon elongation during the ascending phase was fit to a linear regression, the slope of which was defined as stiffness. In addition, the cross-sectional area of the Achilles tendon was measured using ultrasonography. Foot strike patterns (forefoot, midfoot and rearfoot) during running were determined at submaximal velocity (18 km · h(-1)) on a treadmill. The number of each foot strike runner was 12 for the forefoot (29.3%), 12 for the midfoot (29.3%) and 17 for the rearfoot (41.5%). No significant differences were observed in the variables measured for the Achilles tendon among the three groups. These results suggested that the foot strike pattern during running did not affect the morphological or mechanical properties of the Achilles tendon in long-distance runners.

  17. Physical Activity Enhances Metabolic Fitness Independently of Cardiorespiratory Fitness in Marathon Runners

    Directory of Open Access Journals (Sweden)

    M. J. Laye

    2015-01-01

    Full Text Available High levels of cardiovascular fitness (CRF and physical activity (PA are associated with decreased mortality and risk to develop metabolic diseases. The independent contributions of CRF and PA to metabolic disease risk factors are unknown. We tested the hypothesis that runners who run consistently >50 km/wk and/or >2 marathons/yr for the last 5 years have superior metabolic fitness compared to matched sedentary subjects (CRF, age, gender, and BMI. Case-control recruitment of 31 pairs of runner-sedentary subjects identified 10 matched pairs with similar VO2max (mL/min/kg (similar-VO2max. The similar-VO2max group was compared with a group of age, gender, and BMI matched pairs who had the largest difference in VO2max (different-VO2max. Primary outcomes that defined metabolic fitness including insulin response to an oral glucose tolerance test, fasting lipids, and fasting insulin were superior in runners versus sedentary controls despite similar VO2max. Furthermore, performance (velocity at VO2max, running economy, improved exercise metabolism (lactate threshold, and skeletal muscle levels of mitochondrial proteins were superior in runners versus sedentary controls with similar VO2max. In conclusion subjects with a high amount of PA have more positive metabolic health parameters independent of CRF. PA is thus a good marker against metabolic diseases.

  18. The Other World in B.R. Collins' Game Runner (2011

    OpenAIRE

    Fateha Aziz

    2016-01-01

    A brief lecture for an undergrad Sci-fi class at University of Worcester, on the alternative world in B.R. Collins' Game Runner; also a work in progress on the notion of the digitised, consumer childhood in the 21st century.

  19. Excessive exercise habits of runners as new signs of hypertension and arrhythmia.

    Science.gov (United States)

    Kim, Young-Joo; Kim, Chul-Hyun; Park, Kyoung-Min

    2016-08-15

    Excessive exercise may induce arrhythmia, and this risk is higher in middle-aged people. The study aim was to compare the exercise characteristics of middle-aged runners participating in excessive endurance exercise. The subjects of this study were 552 runners (mean age; 49.0±7.4years) without structural heart disease who performed exercise at least twice per week, had consistently exercised for at least three years, and had finished at least five marathons. The arrhythmia runner group (ARG, n=14) and normal runner group (NRG, n=538) were compared with regard to hemodynamic response, cardiorespiratory fitness level, training history, number of finished races, finishing times, and exercise habits. The mean resting systolic (134.0±15.8mmHg) and diastolic (85.8±10.9mmHg) blood pressure values indicated pre-hypertension, while the mean maximal SBP (213.7±27.4mmHg) values indicated exercise-induced hypertension. The VO2max was significantly higher and the maximal DBP was significantly lower in the ARG than in the NRG (phypertension and exercise-induced hypertension, and the ARG had higher VO2max values, greater exercise intensities, and longer training histories than the NRG. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  20. Predisposing Risk Factors and Stress Fractures in Division I Cross Country Runners.

    Science.gov (United States)

    Giffin, Kaci L; Knight, Kathy B; Bass, Martha A; Valliant, Melinda W

    2017-11-11

    The purpose of this study was to explore factors associated with increased stress fractures in collegiate cross country runners. Participants in this study were 42 male and female cross country runners at a Division I university. Each athlete completed a questionnaire regarding smoking status, vitamin/mineral intake, previous stress fracture history, birth control usage, menstrual status, and demographic information. Nutritional assessment via a 3-day food record and measurements of whole body, lumbar spine, and hip bone mineral densities (BMD) were also conducted on each athlete. Results indicated that 40% of the female and 35% of the male runners reported a history of stress fracture, and that all of these did not meet the recommended daily energy intake or adequate intakes for calcium or Vitamin D required for their amount of training. Two-tailed t-test found statistically higher incidences of lumbar spine BMD in males and females whose daily calcium and Vitamin D intakes were below minimum requirements as well as for women whose caloric intake was below the required level. When data on the lumbar spine was evaluated, 31% of participants (31.8% of the male and 30% of the female runners) were identified as having osteopenia and 4.8% with osteoporosis. Results warrant a need for future longitudinal studies.

  1. Comparison of running and cycling economy in runners, cyclists, and triathletes.

    Science.gov (United States)

    Swinnen, Wannes; Kipp, Shalaya; Kram, Rodger

    2018-07-01

    Exercise economy is one of the main physiological factors determining performance in endurance sports. Running economy (RE) can be improved with running-specific training, while the improvement of cycling economy (CE) with cycling-specific training is controversial. We investigated whether exercise economy reflects sport-specific skills/adaptations or is determined by overall physiological factors. We compared RE and CE in 10 runners, 9 cyclists and 9 triathletes for running at 12 km/h and cycling at 200 W. Gross rates of oxygen consumption and carbon dioxide production were collected and used to calculate gross metabolic rate in watts for both running and cycling. Runners had better RE than cyclists (917 ± 107 W vs. 1111 ± 159 W) (p < 0.01). Triathletes had intermediate RE values (1004 ± 98 W) not different from runners or cyclists. CE was not different (p = 0.20) between the three groups (runners: 945 ± 60 W; cyclists: 982 ± 44 W; triathletes: 979 ± 54 W). RE can be enhanced with running-specific training, but CE is independent of cycling-specific training.

  2. Numerical Research on Flow Characteristics around a Hydraulic Turbine Runner at Small Opening of Cylindrical Valve

    Directory of Open Access Journals (Sweden)

    Zhenwei Mo

    2016-01-01

    Full Text Available We use the continuity equation and the Reynolds averaged Navier-Stokes equations to study the flow-pattern characteristics around a turbine runner for the small-opening cylindrical valve of a hydraulic turbine. For closure, we adopt the renormalization-group k-ε two-equation turbulence model and use the computational fluid dynamics (CFD software FLUENT to numerically simulate the three-dimensional unsteady turbulent flow through the entire passage of the hydraulic turbine. The results show that a low-pressure zone develops around the runner blades when the cylindrical valve is closed in a small opening; cavitation occurs at the blades, and a vortex appears at the outlet of the runner. As the cylindrical valve is gradually closed, the flow velocity over the runner area increases, and the pressure gradient becomes more significant as the discharge decreases. In addition, the fluid flow velocity is relatively high between the lower end of the cylindrical valve and the base, so that a high-velocity jet is easily induced. The calculation and analysis provide a theoretical basis for improving the performance of cylindrical-valve operating systems.

  3. A Negative Life Event Impairs Psychosocial Stress, Recovery and Running Economy of Runners

    NARCIS (Netherlands)

    Otter, R. T. A.; Brink, M. S.; Diercks, R. L.; Lemmink, K. A. P. M.

    The purpose was to investigate how a negative life event (NLE) affects perceived psychosocial stress, recovery and running economy (RE). Competitive runners were monitored in a prospective non-experimental cohort study over one full training season in which they experienced the same unplanned severe

  4. Distinct hip and rearfoot kinematics in female runners with a history of tibial stress fracture.

    Science.gov (United States)

    Milner, Clare E; Hamill, Joseph; Davis, Irene S

    2010-02-01

    Cross-sectional controlled laboratory study. To investigate the kinematics of the hip, knee, and rearfoot in the frontal and transverse planes in female distance runners with a history of tibial stress fracture. Tibial stress fractures are a common overuse injury in runners, accounting for up to half of all stress fractures. Abnormal kinematics of the lower extremity may contribute to abnormal musculoskeletal load distributions, leading to an increased risk of stress fractures. Thirty female runners with a history of tibial stress fracture were compared to 30 age-matched and weekly-running-distance-matched control subjects with no previous lower extremity bony injuries. Kinematic and kinetic data were collected using a motion capture system and a force platform, respectively, as subjects ran in the laboratory. Selected variables of interest were compared between the groups using a multivariate analysis of variance (MANOVA). Peak hip adduction and peak rearfoot eversion angles were greater in the stress fracture group compared to the control group. Peak knee adduction and knee internal rotation angles and all joint angles at impact peak were similar between the groups. Runners with a previous tibial stress fracture exhibited greater peak hip adduction and rearfoot eversion angles during the stance phase of running compared to healthy controls. A consequence of these mechanics may be altered load distribution within the lower extremity, predisposing individuals to stress fracture.

  5. Comparison of three-dimensional lower extremity running kinematics of young adult and elderly runners.

    Science.gov (United States)

    Fukuchi, Reginaldo K; Duarte, Marcos

    2008-11-01

    The objective of this study was to compare the three-dimensional lower extremity running kinematics of young adult runners and elderly runners. Seventeen elderly adults (age 67-73 years) and 17 young adults (age 26-36 years) ran at 3.1 m x s(-1) on a treadmill while the movements of the lower extremity during the stance phase were recorded at 120 Hz using three-dimensional video. The three-dimensional kinematics of the lower limb segments and of the ankle and knee joints were determined, and selected variables were calculated to describe the movement. Our results suggest that elderly runners have a different movement pattern of the lower extremity from that of young adults during the stance phase of running. Compared with the young adults, the elderly runners had a substantial decrease in stride length (1.97 vs. 2.23 m; P = 0.01), an increase in stride frequency (1.58 vs. 1.37 Hz; P = 0.002), less knee flexion/extension range of motion (26 vs. 33 degrees ; P = 0.002), less tibial internal/external rotation range of motion (9 vs. 12 degrees ; P heel strike (-5.8 vs. -1.0 degrees ; P = 0.009), and greater asynchronies between the ankle and knee movements during running. These results may help to explain why elderly individuals could be more susceptible to running-related injuries.

  6. Risk models for lower extremity injuries among short- and long distance runners : A prospective cohort study

    NARCIS (Netherlands)

    van Poppel, Dennis; Scholten-Peeters, Gwendolijne G.M.; van Middelkoop, Marienke; Koes, Bart W.; Verhagen, Arianne P.

    2018-01-01

    Background: Running injuries are very common. Risk factors for running injuries are not consistently described across studies and do not differentiate between runners of long- and short distances within one cohort. Objectives: The aim of this study is to determine risk factors for running injuries

  7. Prevalence and incidence rate of injuries in runners at a local athletic club in Cape Town

    Directory of Open Access Journals (Sweden)

    C. Hendricks

    2013-12-01

    Full Text Available People across the world are running on a daily basis to improvetheir health status. However, running can predispose an individual to injuryto the back and lower limb. Baseline data on prevalence, incidence rate ofinjury and aetiological factors associated with running injuries are neededby physiotherapists to develop and implement effective prevention programmesto allow optimal performance in runners. Thus, the purpose of this study wasto determine the prevalence and incidence of injuries in runners at a localathletic club.Methods: A prospective, non-experimental cohort study was conductedover a 16 week period. A sample of 50 runners completed a self-administeredquestionnaire and an injury report form recording injuries sustained during the 16 week study period. Injury prevalence andcumulative incidence was calculated as a proportion rate along with 95% confidence interval.Results: The prevalence rate of injuries was 32%. The incidence rate of injuries was 0.67 per 1000km run (95% CI: 0.41- 1.08.The most common anatomical sites for new injuries were the calf (20% and the knee (18%.Conclusions: The study found a moderate prevalence and incidence rate of injury in runners, thus the need for physiotherapyledinjury surveillance and prevention programmes have been highlighted.

  8. Stress Fracture of the Pubic Ramus in a Female Long Distance Runner: A Case Report

    Directory of Open Access Journals (Sweden)

    Seçkin Şenışık

    2017-06-01

    Stress fractures of the pelvis should be included in the differential diagnosis of female distance runners who have prolonged groin pain increasing with exercise. Detailed medical history, physical examination, blood tests, and radiological images are keys to reach certain diagnosis. Treatment plan should include risk factor analysis and progressive training programs.

  9. The impact of injury definition on injury surveillance in novice runners

    NARCIS (Netherlands)

    Kluitenberg, Bas; van Middelkoop, Marienke; Verhagen, Evert; Hartgens, Fred; Huisstede, Bionka; Diercks, Ron; van der Worp, Henk

    2016-01-01

    Objectives: Despite several consensus statements, different injury definitions are used in the literature. This study aimed to identify the impact of different injury definitions on the nature and incidence of complaints captured during a short-term running program for novice runners. Design:

  10. Dynamic observation of vegetative support of central hemodynamics and physical performance in 400-m runners

    Directory of Open Access Journals (Sweden)

    E. L. Mikhalyuk

    2016-01-01

    Full Text Available At the present time problem of human physical performance is relevant, especially in sports, because athletes can achieve good results mostly due to the high level of physical performance. Aim. To determine and compare heart rate variability, central hemodynamics and physical performance in runners at a distance of 400 m, obtained in the preparatory and competitive periods of training process. Results. The study of the functional state of the 400 m runners showed strengthening of parasympathetic effects of the autonomic nervous system (ANS in the competitive period. Also eukinetic circulation type transformation into hypokinetic occurred. Significant increase in physical performance by 8.5% and the IFS by 17.9% was detected. High class runners separate study showed the prevalence of parasympathetic effects of the ANS, hypokinetic circulation type (CT and lack of athletes with hyperkinetic CT. Significant increase in physical performance at 7.95% and the IFS by 20.2% was detected in them. Athletes with II–III level of qualification in the preparatory period had sighs of the increased parasympathetic ANS similar with eukinetic CT. Nobody had hyperkinetic CT. Conclusions. Correlation analysis between the integrated parameters in the whole group of runners in the competitive period found no significant correlations between the studied parameters.

  11. Serum lipid levels and steroidal hormones in women runners with irregular menses.

    Science.gov (United States)

    Thompson, D L; Snead, D B; Seip, R L; Weltman, J Y; Rogol, A D; Weltman, A

    1997-02-01

    This study compared the lipid profile of women runners with menstrual cycle irregularities with their normally menstruating counterparts. Relationships among selected steroid hormones and serum lipid levels in 10 eumenorrheic (EU) and 8 oligo-/amenorrheic (O/A) women runners and 6 eumenorrheic controls (CON) were examined. Serum 17 beta-estradiol (E2), progesterone (Prog), and dehydroepiandrosterone-sulfate (DHEAS) concentrations were determined in daily blood samples for 21 days, and integrated concentrations were calculated. Fasting blood samples were analyzed for total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), HDL2, HDL3, triglycerides (Trig), and apolipoproteins A-1, A-II, and B. The O/A group had significantly lower E2 and Prog than EU or CON groups. Women in the CON group had lower HDL-C and HDL3 than the runners. With all women grouped together, E2 was not significantly correlated with any measured blood lipid parameters. On the other hand, DHEAS was significantly correlated with HDL-C, HDL2, and apolipoprotein A-I. These data demonstrate that women runners, regardless of menstrual cycle status, exhibit higher HDL-C concentrations than CON and supports previous research reporting a positive association between DHEAS and HDL-C.

  12. Reliability and accuracy of Cooper's test in male long distance runners

    Directory of Open Access Journals (Sweden)

    J.R. Alvero-Cruz

    2017-06-01

    Conclusions: All together, our results may confirm a good accuracy and reliability of Cooper's test in amateur long distance runners. Also, improvements or impairment lower than 52.2 m must not be associated with exercise training or retraining, since they are below the values of intra-subject reliability.

  13. ASSOCIATION OF ISOMETRIC STRENGTH OF HIP AND KNEE MUSCLES WITH INJURY RISK IN HIGH SCHOOL CROSS COUNTRY RUNNERS.

    Science.gov (United States)

    Luedke, Lace E; Heiderscheit, Bryan C; Williams, D S Blaise; Rauh, Mitchell J

    2015-11-01

    High school cross country runners have a high incidence of overuse injuries, particularly to the knee and shin. As lower extremity strength is modifiable, identification of strength attributes that contribute to anterior knee pain (AKP) and shin injuries may influence prevention and management of these injuries. To determine if a relationship existed between isometric hip abductor, knee extensor and flexor strength and the incidence of AKP and shin injury in high school cross country runners. Sixty-eight high school cross country runners (47 girls, 21 boys) participated in the study. Isometric strength tests of hip abductors, knee extensors and flexors were performed with a handheld dynamometer. Runners were prospectively followed during the 2014 interscholastic cross country season for occurrences of AKP and shin injury. Bivariate logistic regression was used to examine risk relationships between strength values and occurrence of AKP and shin injury. During the season, three (4.4%) runners experienced AKP and 13 (19.1%) runners incurred a shin injury. Runners in the tertiles indicating weakest hip abductor (chi-square = 6.140; p=0.046), knee extensor (chi-square = 6.562; p=0.038), and knee flexor (chi-square = 6.140; p=0.046) muscle strength had a significantly higher incidence of AKP. Hip and knee muscle strength was not significantly associated with shin injury. High school cross country runners with weaker hip abductor, knee extensor and flexor muscle strength had a higher incidence of AKP. Increasing hip and knee muscle strength may reduce the likelihood of AKP in high school cross country runners. 2b.

  14. Monitoring of total body water to examine the progress of acclimatization of runners at varying altitudes

    Directory of Open Access Journals (Sweden)

    Miroslav Semerád

    2017-11-01

    Full Text Available The purpose of our pilot study was to find out if total body water (TBW changes could objectively modify the course of adaptation during training for elite runners at different altitudes. The aim of this pilot study is to summarize the indication of the progress of acclimatization at high altitudes (1000–2700 meters above sea level during alpine conditioning. In three training camps at various altitudes the TBW of elite runners (F = 3, M = 1; n = 4; age 23 } 0.9 was monitored, in order to check the progress of acclimatization. We used BIA measurement methods (Bodystat 1500 at different high altitude running camps at the Czech Republic, Morocco and Ethiopia. Changes in TBW were used to check the progress of acclimatization. We discovered that the retention peaks of TBW corresponded with critical days (p ≤ 0.04; Cohen’s d. The highest measured increases of TBW at an altitude of 1000 m were for runner 1, 1.7 litres and for runner 2, 2.1 litres with retention peaks for both occurring on the 5th day. At an altitude of 1770 m runner 1 reached an increase of TBW of 6.3 litres, with a retention peak on the 11th day, and runner 3 had an increase of 5.1 litres with a peak on the 8th day. In the acclimatization phase we found two critical periods, from the 4th–6th day, and after the 10th–12th day. For runner 4 in altitude 2700m who completed the camp at a higher altitude, the situation is more complicated because there were fluctuations of the content of TBW in the range of 1.25 litres, with the highest depression on the 5th and then again an unsettled rise and reaching a maximum on the 12th, when she nearly returned to the initial value. Detected retention peaks reflected different levels of altitude (5th–12th days.We can conclude that the measuring of changes in TBW during camps at higher altitudes may be one of the biomarkers during acclimatization to altitude.

  15. libRoadRunner: a high performance SBML simulation and analysis library.

    Science.gov (United States)

    Somogyi, Endre T; Bouteiller, Jean-Marie; Glazier, James A; König, Matthias; Medley, J Kyle; Swat, Maciej H; Sauro, Herbert M

    2015-10-15

    This article presents libRoadRunner, an extensible, high-performance, cross-platform, open-source software library for the simulation and analysis of models expressed using Systems Biology Markup Language (SBML). SBML is the most widely used standard for representing dynamic networks, especially biochemical networks. libRoadRunner is fast enough to support large-scale problems such as tissue models, studies that require large numbers of repeated runs and interactive simulations. libRoadRunner is a self-contained library, able to run both as a component inside other tools via its C++ and C bindings, and interactively through its Python interface. Its Python Application Programming Interface (API) is similar to the APIs of MATLAB ( WWWMATHWORKSCOM: ) and SciPy ( HTTP//WWWSCIPYORG/: ), making it fast and easy to learn. libRoadRunner uses a custom Just-In-Time (JIT) compiler built on the widely used LLVM JIT compiler framework. It compiles SBML-specified models directly into native machine code for a variety of processors, making it appropriate for solving extremely large models or repeated runs. libRoadRunner is flexible, supporting the bulk of the SBML specification (except for delay and non-linear algebraic equations) including several SBML extensions (composition and distributions). It offers multiple deterministic and stochastic integrators, as well as tools for steady-state analysis, stability analysis and structural analysis of the stoichiometric matrix. libRoadRunner binary distributions are available for Mac OS X, Linux and Windows. The library is licensed under Apache License Version 2.0. libRoadRunner is also available for ARM-based computers such as the Raspberry Pi. http://www.libroadrunner.org provides online documentation, full build instructions, binaries and a git source repository. hsauro@u.washington.edu or somogyie@indiana.edu Supplementary data are available at Bioinformatics online. Published by Oxford University Press 2015. This work is written

  16. Changes in vigorous physical activity and incident diabetes inmale runners

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Paul T.

    2007-04-30

    We examined the dose-response relationship between changes in reported vigorous exercise (running distance, {Delta}km/wk) and self-reported physician diagnosed diabetes in 25,988 men followed prospectively for (mean {+-} SD) 7.8 {+-} 1.8 years. Logistic regression analyses showed that the log odds for diabetes declined significantly in relation to men's {Delta}km/wk (coefficient {+-} SE: -0.012 {+-} 0.004, P < 0.01), which remained significant when adjusted for BMI (-0.018 {+-} 0.003, P < 0.0001). The decline in the log odds for diabetes was related to the distance run at the end of follow-up when adjusted for baseline distance, with (-0.024 {+-} 0.005, P < 0.0001) or without (-0.027 {+-} 0.005, P < 0.0001) adjustment for BMI. Baseline distance was unrelated to diabetes incidence when adjusted for the distance at the end of follow-up. Compared to men who ran <8 km/wk at the end of follow-up, incidence rates in those who ran {ge} 8 km/wk were 95% lower between 35-44 yrs old (P < 0.0001), 92% lower between 45-54 yrs old (P < 0.0001), 87% lower between 55 and 64 years old (P < 0.0001), and 46% lower between 65-75 yrs old (P = 0.30). For the subset of 6,208 men who maintained the same running distance during follow-up ({+-}5 km/wk), the log odds for diabetes declined with weekly distance run (-0.024 {+-} 0.010, P = 0.02) but not when adjusted for BMI (-0.005 {+-} 0.010, P = 0.65). Conclusion: Vigorous exercise significantly reduces diabetes incidence, due in part to the prevention of age-related weight gain and in part to other exercise effects. Physical activity decreases the risk of type 2 diabetes [1-10]. Moderate and vigorous exercise are purported to produce comparable reductions in diabetes risk if the energy expenditure is the same [3,10]. The optimal physical activity dose remains unclear, however, with some [4-7] but not all studies [1,8,9] showing continued reduction in diabetes for high versus intermediate energy expenditures. The National Runners

  17. Peripheral Artery Disease

    Science.gov (United States)

    ... pressure High blood cholesterol Coronary heart disease Stroke Metabolic syndrome Screening and Prevention Taking action to control your risk factors can help prevent or delay peripheral artery disease (P.A.D.) and its complications. Know your family history of health problems related to P.A. ...

  18. Promoting peripheral myelin repair.

    Science.gov (United States)

    Zhou, Ye; Notterpek, Lucia

    2016-09-01

    Compared to the central nervous system (CNS), peripheral nerves have a remarkable ability to regenerate and remyelinate. This regenerative capacity to a large extent is dependent on and supported by Schwann cells, the myelin-forming glial cells of the peripheral nervous system (PNS). In a variety of paradigms, Schwann cells are critical in the removal of the degenerated tissue, which is followed by remyelination of newly-regenerated axons. This unique plasticity of Schwann cells has been the target of myelin repair strategies in acute injuries and chronic diseases, such as hereditary demyelinating neuropathies. In one approach, the endogenous regenerative capacity of Schwann cells is enhanced through interventions such as exercise, electrical stimulation or pharmacological means. Alternatively, Schwann cells derived from healthy nerves, or engineered from different tissue sources have been transplanted into the PNS to support remyelination. These transplant approaches can then be further enhanced by exercise and/or electrical stimulation, as well as by the inclusion of biomaterial engineered to support glial cell viability and neurite extension. Advances in our basic understanding of peripheral nerve biology, as well as biomaterial engineering, will further improve the functional repair of myelinated peripheral nerves. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Water and sodium intake habits and status of ultra-endurance runners during a multi-stage ultra-marathon conducted in a hot ambient environment: an observational field based study

    Directory of Open Access Journals (Sweden)

    Costa Ricardo JS

    2013-01-01

    Full Text Available Abstract Background Anecdotal evidence suggests ultra-runners may not be consuming sufficient water through foods and fluids to maintenance euhydration, and present sub-optimal sodium intakes, throughout multi-stage ultra-marathon (MSUM competitions in the heat. Subsequently, the aims were primarily to assess water and sodium intake habits of recreational ultra-runners during a five stage 225 km semi self-sufficient MSUM conducted in a hot ambient environment (Tmax range: 32°C to 40°C; simultaneously to monitor serum sodium concentration, and hydration status using multiple hydration assessment techniques. Methods Total daily, pre-stage, during running, and post-stage water and sodium ingestion of ultra-endurance runners (UER, n = 74 and control (CON, n = 12 through foods and fluids were recorded on Stages 1 to 4 by trained dietetic researchers using dietary recall interview technique, and analysed through dietary analysis software. Body mass (BM, hydration status, and serum sodium concentration were determined pre- and post-Stages 1 to 5. Results Water (overall mean (SD: total daily 7.7 (1.5 L/day, during running 732 (183 ml/h and sodium (total daily 3.9 (1.3 g/day, during running 270 (151 mg/L ingestion did not differ between stages in UER (p vs. CON. Exercise-induced BM loss was 2.4 (1.2% (p p > 0.05 vs. CON pre-stage. Asymptomatic hyponatraemia (n = 8 UER, corresponding to 42% of sampled participants. Pre- and post-stage urine colour, urine osmolality and urine/plasma osmolality ratio increased (p p  Conclusion Water intake habits of ultra-runners during MSUM conducted in hot ambient conditions appear to be sufficient to maintain baseline euhydration levels. However, fluid over-consumption behaviours were evident along competition, irrespective of running speed and gender. Normonatraemia was observed in the majority of ultra-runners throughout MSUM, despite sodium ingestion under benchmark recommendations.

  20. Ankle and toe muscle strength characteristics in runners with a history of medial tibial stress syndrome.

    Science.gov (United States)

    Saeki, Junya; Nakamura, Masatoshi; Nakao, Sayaka; Fujita, Kosuke; Yanase, Ko; Morishita, Katsuyuki; Ichihashi, Noriaki

    2017-01-01

    A high proportion of flexor digitorum longus attachment is found at the posteromedial border of the tibia, which is the most common location of medial tibial stress syndrome (MTSS). Therefore, plantar flexion strength of the lesser toes could be related to MTSS; however, the relationship between MTSS and muscle strength of the hallux and lesser toes is not yet evaluated due to the lack of quantitative methods. This study investigated the muscle strength characteristics in runners with a history of MTSS by using a newly developed device to measure the muscle strength of the hallux, lesser toes, and ankle. This study comprised 27 collegiate male runner participants (20.0 ± 1.6 years, 172.1 ± 5.1 cm, 57.5 ± 4.0 kg). Maximal voluntary isometric contraction (MVIC) torque of the plantar flexion, dorsiflexion, inversion, and eversion of the ankle were measured by using an electric dynamometer. MVIC torque of the 1st metatarsophalangeal joint (MTPJ) and 2nd-5th MTPJ were measured by using a custom-made torque-measuring device. MVIC torques were compared between runners with and without a history of MTSS. MVIC torque of the 1st MTPJ plantar flexion was significantly higher in runners with a history of MTSS than in those without it. In contrast, there were no significant differences in the MVIC torque values of the 2nd-5th MTPJ plantar flexion and each MVIC torque of the ankle between runners with and without a history of MTSS. A history of MTSS increased the isometric FHL strength.

  1. Male and female runners demonstrate different sagittal plane mechanics as a function of static hamstring flexibility

    Science.gov (United States)

    Williams III, D. S. Blaise; Welch, Lee M.

    2015-01-01

    ABSTRACT Background: Injuries to runners are common. However, there are many potential contributing factors to injury. While lack of flexibility alone is commonly related to injury, there are clear differences in hamstring flexibility between males and females. Objective: To compare the effect of static hamstring length on sagittal plane mechanics between male and female runners. Method: Forty subjects (30.0±6.4 years) participated and were placed in one of 4 groups: flexible males (n=10), inflexible males (n=10), flexible females (n=10), and inflexible females (n=10). All subjects were free of injury at the time of data collection. Three-dimensional kinematics and kinetics were collected while subjects ran over ground across 2 force platforms. Sagittal plane joint angles and moments were calculated at the knee and hip and compared with a 2-way (sex X flexibility) ANOVA (α=0.05). Results: Males exhibited greater peak knee extension moment than females (M=2.80±0.47, F=2.48±0.52 Nm/kg*m, p=0.05) and inflexible runners exhibited greater peak knee extension moment than flexible runners (In=2.83±0.56, Fl=2.44±0.51 Nm/kg*m, p=0.01). For hip flexion at initial contact, a significant interaction existed (pHamstring flexibility results in different mechanical profiles in males and females. Flexibility in the hamstrings may result in decreased moments via active or passive tension. These differences may have implications for performance and injury in flexible female runners. PMID:26537812

  2. The impact of hepatitis B carrier on cardiac troponin I in 100-km ultramarathon runners.

    Science.gov (United States)

    Li, Li-Hua; How, Chorng-Kuang; Kao, Wei-Fong; Chiu, Yu-Hui; Meng, Chen; Hsu, Cheng-Chin; Tsay, Yeou-Guang

    2017-06-01

    Prolonged endurance exercise is known to cause elevation of cardiac troponin I (cTnI). Previous studies have reported the correlation of several factors with exercise-induced cTnI release. However, the investigation of the predictors for elevated cTnI and postrace kinetics of cTnI after ultramarathon running is lacking, especially in an Oriental population. Twenty-six participants, including eight hepatitis B virus carrier (HBVc) runners, who finished a 100-km ultramarathon in Taiwan were enrolled. For each participant, blood samples were collected 1 week before the race, as well as immediately and 24 hours after the finish. The results showed that 19 runners (73.1%) had postrace elevated cTnI levels and eight (30.8%) had elevated cTnI values lasting more than 24 hours after the run. A multiple linear regression analysis demonstrated that the HBV status was a factor related to the high level of cTnI after 24 hours of running (β=0.03, p=0.08). The recovery of plasma cTnI levels was delayed in ultramarathon runners with latent HBV infection. Among HBVc runners, multiple linear regression analyses showed age (β=-0.01), previous running experience (β=-0.06), training distance (β=0.37), and 4 hours of running distance (β=-0.04) as significant predictors of higher postrace cTnI levels. For most athletes, cTnI values significantly increased immediately following the race in the absence of adverse clinical sequelae, and HBVc runners had higher and prolonged cTnI levels. While several factors are identified for such HBV effects, the specific causes need further elucidation. Copyright © 2017. Published by Elsevier Taiwan LLC.

  3. Efficient runner safety assessment during early design phase and root cause analysis

    International Nuclear Information System (INIS)

    Liang, Q W; Lais, S; Gentner, C; Braun, O

    2012-01-01

    Fatigue related problems in Francis turbines, especially high head Francis turbines, have been published several times in the last years. During operation the runner is exposed to various steady and unsteady hydraulic loads. Therefore the analysis of forced response of the runner structure requires a combined approach of fluid dynamics and structural dynamics. Due to the high complexity of the phenomena and due to the limitation of computer power, the numerical prediction was in the past too expensive and not feasible for the use as standard design tool. However, due to continuous improvement of the knowledge and the simulation tools such complex analysis has become part of the design procedure in ANDRITZ HYDRO. This article describes the application of most advanced analysis techniques in runner safety check (RSC), including steady state CFD analysis, transient CFD analysis considering rotor stator interaction (RSI), static FE analysis and modal analysis in water considering the added mass effect, in the early design phase. This procedure allows a very efficient interaction between the hydraulic designer and the mechanical designer during the design phase, such that a risk of failure can be detected and avoided in an early design stage.The RSC procedure can also be applied to a root cause analysis (RCA) both to find out the cause of failure and to quickly define a technical solution to meet the safety criteria. An efficient application to a RCA of cracks in a Francis runner is quoted in this article as an example. The results of the RCA are presented together with an efficient and inexpensive solution whose effectiveness could be proven again by applying the described RSC technics. It is shown that, with the RSC procedure developed and applied as standard procedure in ANDRITZ HYDRO such a failure is excluded in an early design phase. Moreover, the RSC procedure is compatible with different commercial and open source codes and can be easily adapted to apply for

  4. Efficient runner safety assessment during early design phase and root cause analysis

    Science.gov (United States)

    Liang, Q. W.; Lais, S.; Gentner, C.; Braun, O.

    2012-11-01

    Fatigue related problems in Francis turbines, especially high head Francis turbines, have been published several times in the last years. During operation the runner is exposed to various steady and unsteady hydraulic loads. Therefore the analysis of forced response of the runner structure requires a combined approach of fluid dynamics and structural dynamics. Due to the high complexity of the phenomena and due to the limitation of computer power, the numerical prediction was in the past too expensive and not feasible for the use as standard design tool. However, due to continuous improvement of the knowledge and the simulation tools such complex analysis has become part of the design procedure in ANDRITZ HYDRO. This article describes the application of most advanced analysis techniques in runner safety check (RSC), including steady state CFD analysis, transient CFD analysis considering rotor stator interaction (RSI), static FE analysis and modal analysis in water considering the added mass effect, in the early design phase. This procedure allows a very efficient interaction between the hydraulic designer and the mechanical designer during the design phase, such that a risk of failure can be detected and avoided in an early design stage.The RSC procedure can also be applied to a root cause analysis (RCA) both to find out the cause of failure and to quickly define a technical solution to meet the safety criteria. An efficient application to a RCA of cracks in a Francis runner is quoted in this article as an example. The results of the RCA are presented together with an efficient and inexpensive solution whose effectiveness could be proven again by applying the described RSC technics. It is shown that, with the RSC procedure developed and applied as standard procedure in ANDRITZ HYDRO such a failure is excluded in an early design phase. Moreover, the RSC procedure is compatible with different commercial and open source codes and can be easily adapted to apply for

  5. Physiological characteristics of the best Eritrean runners-exceptional running economy.

    Science.gov (United States)

    Lucia, Alejandro; Esteve-Lanao, Jonathan; Oliván, Jesús; Gómez-Gallego, Félix; San Juan, Alejandro F; Santiago, Catalina; Pérez, Margarita; Chamorro-Viña, Carolina; Foster, Carl

    2006-10-01

    Despite their young age, limited training history, and lack of running tradition compared with other East African endurance athletes (e.g., Kenyans and Ethiopians), male endurance runners from Eritrea have recently attained important running successes. The purposes of our study were (i) to document the main physical and physiological characteristics of elite black Eritrean distance runners (n = 7; age: 22 +/- 3 years) and (ii) to compare them with those of their elite white Spanish counterparts. For this second purpose we selected a control group of elite Spanish runners (n = 9; 24 +/- 2 years), owing to the traditionally high success of Spanish athletes in long-distance running compared with other white runners, especially in cross-country competitions. The subjects' main anthropometric characteristics were determined, together with their maximum oxygen uptake (VO2 max) and VO2 (mL.kg(-1).min(-1)), blood lactate, and ammonia concentrations while running at 17, 19, or 21 km.h(-1). The body mass index (18.9 +/- 1.5 kg.m(-2)) and maximal calf circumference (30.9 +/- 1.5 cm) was lower in Eritreans than in Spaniards (20.5 +/- 1.7 kg.m(-2) and 33.9 +/- 2.0 cm, respectively) (p economy of Eritreans is associated, at least partly, with anthropometric variables. Comparison of their submaximal running cost with other published data suggests that superior running economy, rather than enhanced aerobic capacity, may be the common denominator in the success of black endurance runners of East African origin.

  6. Comparison of Site-Specific Bone Mineral Densities between Endurance Runners and Sprinters in Adolescent Women

    Directory of Open Access Journals (Sweden)

    Aoi Ikedo

    2016-11-01

    Full Text Available We aimed to compare site-specific bone mineral densities (BMDs between adolescent endurance runners and sprinters and examine the relationship of fat-free mass (FFM and nutrient intake on BMD. In this cross-sectional study, 37 adolescent female endurance runners and sprinters (16.1 ± 0.8 years were recruited. BMD and FFM were assessed by dual-energy X-ray absorptiometry. Nutrient intake and menstrual state were evaluated by questionnaires. After adjusting for covariates, spine and total bone less head (TBLH BMDs were significantly higher in sprinters than endurance runners (TBLH, 1.02 ± 0.05 vs. 0.98 ± 0.06 g/cm2; spine, 0.99 ± 0.06 vs. 0.94 ± 0.06 g/cm2; p < 0.05. There was no significant difference between groups in other sites. The rate of menstrual abnormality was higher in endurance runners compared with sprinters (56.3% vs. 23.8%; p < 0.05. FFM was a significant covariate for BMD on all sites except the spine (p < 0.05. Dietary intake of vitamin D was identified as a significant covariate only for pelvic BMD (p < 0.05. The BMDs of different sites among endurance runners and sprinters were strongly related to FFM. However, the association of FFM with spine BMD cannot be explained by FFM alone. Other factors, including nutrition and/or mechanical loading, may affect the spine BMD.

  7. Understanding Trail Runners' Activity on Online Community Forums: An Inductive Analysis of Discussion Topics.

    Science.gov (United States)

    Rochat, Nadège; Hauw, Denis; Gür, Gaëlle; Seifert, Ludovic

    2018-03-01

    Recreational trail runners often participate in online community forums where they can freely read posted messages, join discussions and/or introduce new discussion topics. This tool can enhance learning as runners connect with other trail runners and reflect on how they can better organize their own practice. Studying forum activity would provide greater insight into the relationship between field practice and dedicated forums. The aim of this study was therefore to detect the topics discussed online by trail runners in order to understand how they collectively look for solutions that help them adapt to issues that emerge during actual practice. The discussion topics (n = 171) on the forum hosted by the Raidlight brand were examined using inductive content analysis, which distinguished two general dimensions. The first dimension was training and had four first-order themes (i.e., "specific trail running sessions", "complementary trail running sessions". "training plans" and "specific questions about races") grouped into two second-order themes (i.e., "training session contents" and "structure and schedule"). The second dimension was health and had seven first-order themes (i.e., "tendinitis", "muscle issues", "foot issues", "sprains and fractures", "pain", "physiology" and "substances and practitioners") grouped into two second-order themes (i.e., "pain and injury" and "prevention"). The results indicate that the issues that trail runners discuss on forums are significant and that the successions of questions and solutions are a fruitful means for building, enriching and adjusting their activity as they cope with constraints. As a practical consequence, suggestions for improving such online platforms are made.

  8. Risk factors for stress fracture among young female cross-country runners.

    Science.gov (United States)

    Kelsey, Jennifer L; Bachrach, Laura K; Procter-Gray, Elizabeth; Nieves, Jeri; Greendale, Gail A; Sowers, Maryfran; Brown, Byron W; Matheson, Kim A; Crawford, Sybil L; Cobb, Kristin L

    2007-09-01

    To identify risk factors for stress fracture among young female distance runners. Participants were 127 competitive female distance runners, aged 18-26, who provided at least some follow-up data in a randomized trial among 150 runners of the effects of oral contraceptives on bone health. After completing a baseline questionnaire and undergoing bone densitometry, they were followed an average of 1.85 yr. Eighteen participants had at least one stress fracture during follow-up. Baseline characteristics associated (Pstress fracture occurrence were one or more previous stress fractures (rate ratio [RR] [95% confidence interval]=6.42 (1.80-22.87), lower whole-body bone mineral content (RR=2.70 [1.26-5.88] per 1-SD [293.2 g] decrease), younger chronologic age (RR=1.42 [1.05-1.92] per 1-yr decrease), lower dietary calcium intake (RR=1.11 [0.98-1.25] per 100-mg decrease), and younger age at menarche (RR=1.92 [1.15-3.23] per 1-yr decrease). Although not statistically significant, a history of irregular menstrual periods was also associated with increased risk (RR=3.41 [0.69-16.91]). Training-related factors did not affect risk. The results of this and other studies indicate that risk factors for stress fracture among young female runners include previous stress fractures, lower bone mass, and, although not statistically significant in this study, menstrual irregularity. More study is needed of the associations between stress fracture and age, calcium intake, and age at menarche. Given the importance of stress fractures to runners, identifying preventive measures is of high priority.

  9. Shorter Ground Contact Time and Better Running Economy: Evidence From Female Kenyan Runners.

    Science.gov (United States)

    Mooses, Martin; Haile, Diresibachew W; Ojiambo, Robert; Sang, Meshack; Mooses, Kerli; Lane, Amy R; Hackney, Anthony C

    2018-06-25

    Mooses, M, Haile, DW, Ojiambo, R, Sang, M, Mooses, K, Lane, AR, and Hackney, AC. Shorter ground contact time and better running economy: evidence from female Kenyan runners. J Strength Cond Res XX(X): 000-000, 2018-Previously, it has been concluded that the improvement in running economy (RE) might be considered as a key to the continued improvement in performance when no further increase in V[Combining Dot Above]O2max is observed. To date, RE has been extensively studied among male East African distance runners. By contrast, there is a paucity of data on the RE of female East African runners. A total of 10 female Kenyan runners performed 3 × 1,600-m steady-state run trials on a flat outdoor clay track (400-m lap) at the intensities that corresponded to their everyday training intensities for easy, moderate, and fast running. Running economy together with gait characteristics was determined. Participants showed moderate to very good RE at the first (202 ± 26 ml·kg·km) and second (188 ± 12 ml·kg·km) run trials, respectively. Correlation analysis revealed significant relationship between ground contact time (GCT) and RE at the second run (r = 0.782; p = 0.022), which represented the intensity of anaerobic threshold. This study is the first to report the RE and gait characteristics of East African female athletes measured under everyday training settings. We provided the evidence that GCT is associated with the superior RE of the female Kenyan runners.

  10. Male and female runners demonstrate different sagittal plane mechanics as a function of static hamstring flexibility.

    Science.gov (United States)

    Williams, D S Blaise; Welch, Lee M

    2015-01-01

    Injuries to runners are common. However, there are many potential contributing factors to injury. While lack of flexibility alone is commonly related to injury, there are clear differences in hamstring flexibility between males and females. To compare the effect of static hamstring length on sagittal plane mechanics between male and female runners. Forty subjects (30.0±6.4 years) participated and were placed in one of 4 groups: flexible males (n=10), inflexible males (n=10), flexible females (n=10), and inflexible females (n=10). All subjects were free of injury at the time of data collection. Three-dimensional kinematics and kinetics were collected while subjects ran over ground across 2 force platforms. Sagittal plane joint angles and moments were calculated at the knee and hip and compared with a 2-way (sex X flexibility) ANOVA (α=0.05). Males exhibited greater peak knee extension moment than females (M=2.80±0.47, F=2.48±0.52 Nm/kg*m, p=0.05) and inflexible runners exhibited greater peak knee extension moment than flexible runners (In=2.83±0.56, Fl=2.44±0.51 Nm/kg*m, p=0.01). For hip flexion at initial contact, a significant interaction existed (pHamstring flexibility results in different mechanical profiles in males and females. Flexibility in the hamstrings may result in decreased moments via active or passive tension. These differences may have implications for performance and injury in flexible female runners.

  11. Oxygen consumption of elite distance runners on an anti-gravity treadmill®.

    Science.gov (United States)

    McNeill, David K P; Kline, John R; de Heer, Hendrick D; Coast, J Richard

    2015-06-01

    Lower body positive pressure (LBPP), or 'anti-gravity' treadmills® have become increasingly popular among elite distance runners. However, to date, few studies have assessed the effect of body weight support (BWS) on the metabolic cost of running among elite runners. This study evaluated how BWS influenced the relationship between velocity and metabolic cost among 6 elite male distance runners. Participants ran three- 16 minute tests consisting of 4 stages of 4 minutes at 8, 7, 6 and 5 min·mile(-1) pace (3.35, 3.84, 4.47 and 5.36 m·s(-1)), while maintaining an aerobic effort (Respiratory Exchange Ratio ≤1.00). One test was run on a regular treadmill, one on an anti-gravity treadmill with 40% BWS and one with 20% BWS being provided. Expired gas data were collected and regression equations used to determine and compare slopes. Significant decreases in oxygen uptake (V̇O2) were found with each increase in BWS (p rate, perceived exertion or directly measured oxygen uptake) should be used to guide training intensity when training on the LBPP treadmill. Key pointsWith increasing amounts of body weight-support (BWS), the slope of the relationship between velocity and oxygen consumption (ΔVO2/Δv) decreases significantly. This means the change in oxygen consumption (VO2) is significantly smaller over a given change in velocity at higher amounts of BWS.There is a non-linear decrease in VO2 with increasing BWS. As such, with each increment in the amount of BWS provided, the reduction in VO2 becomes increasingly smaller.This paper provides first of its kind data on the effects of BWS on the cost of running among highly trained, elite runners. The outcomes of this study are in line with previous findings among non-elite runners.

  12. Influence of regression model and incremental test protocol on the relationship between lactate threshold using the maximal-deviation method and performance in female runners.

    Science.gov (United States)

    Machado, Fabiana Andrade; Nakamura, Fábio Yuzo; Moraes, Solange Marta Franzói De

    2012-01-01

    This study examined the influence of the regression model and initial intensity of an incremental test on the relationship between the lactate threshold estimated by the maximal-deviation method and the endurance performance. Sixteen non-competitive, recreational female runners performed a discontinuous incremental treadmill test. The initial speed was set at 7 km · h⁻¹, and increased every 3 min by 1 km · h⁻¹ with a 30-s rest between the stages used for earlobe capillary blood sample collection. Lactate-speed data were fitted by an exponential-plus-constant and a third-order polynomial equation. The lactate threshold was determined for both regression equations, using all the coordinates, excluding the first and excluding the first and second initial points. Mean speed of a 10-km road race was the performance index (3.04 ± 0.22 m · s⁻¹). The exponentially-derived lactate threshold had a higher correlation (0.98 ≤ r ≤ 0.99) and smaller standard error of estimate (SEE) (0.04 ≤ SEE ≤ 0.05 m · s⁻¹) with performance than the polynomially-derived equivalent (0.83 ≤ r ≤ 0.89; 0.10 ≤ SEE ≤ 0.13 m · s⁻¹). The exponential lactate threshold was greater than the polynomial equivalent (P performance index that is independent of the initial intensity of the incremental test and better than the polynomial equivalent.

  13. Measures for speed management.

    NARCIS (Netherlands)

    2009-01-01

    Measures for speed management are essential for limiting the negative effects of driving too fast and at inappropriate speeds. To begin with, safe and credible speed limits need to be determined. Dynamic and variable speed limits that take into account the current circumstances, such as weather

  14. Peripheral orbit model

    CERN Document Server

    Hara, Yasuo

    1975-01-01

    Peripheral orbit model, in which an incoming hadron is assumed to revolve in a peripheral orbit around a target hadron, is discussed. The non-diffractive parts of two-body reaction amplitudes of hadrons are expressed in terms of the radius, width an absorptivity of the orbit. The radius of the orbit is about 1 fm and the width of the orbit is determined by the range of the interaction between the hadrons. The model reproduces all available experimental data on differential cross-sections and polarizations of $K^{-}p\\to K^{-}p$ and $\\bar K^{\\circ}n$ reactions for all angles successfully. This contribution is not included in the proceedings since it will appear in Progress of Theoretical Physics Vol. 51 (1974) No 2. Any person interested in the subject may apply for reprints to the author.

  15. Differences in energy capacities between tennis players and runners.

    Science.gov (United States)

    Novak, Dario; Vucetić, Vlatko; Zugaj, Sanja

    2013-05-01

    The primary purpose of this study was to determine differences between elite athletes and tennis players in order to provide a clearer picture regarding the energy demands in modern tennis. Forty-eight (48) athletes and 24 tennis players from Croatian national leagues were compared in morphological and physiological parameters of an all-out incremental treadmill test with gas exchange measurements. Tennis players' HRmax (192.96+/-7.75 bpm) shows values that are most different to 400-meters sprinters (200.13+/-6.95 bpm). Maximum running speed of tennis players on the treadmill (vmax) is no different with the speed achieved by sprinters, while there are significant differences among other athletes. Values in running speed at anaerobic threshold (vAnT) show no statistically significant difference with the values for athlete sprinters and 400-m sprinters. Values of RvO2max for tennis players indicate significant similarities with athlete sprinters and 400-m sprinters while the values of RvO2AnT are nearly identical with the values for sprinters and show no statistically significant differences (psprint endurance in tennis players. Knowing these characteristics is the basis for planning and implementing training systems that will enable the increase and optimal usage of energy capacities of tennis players in possibly improving sports results.

  16. Short-Term Absenteeism and Health Care Utilization Due to Lower Extremity Injuries Among Novice Runners : A Prospective Cohort Study

    NARCIS (Netherlands)

    Smits, Dirk-Wouter; Huisstede, Bionka; Verhagen, Evert; van der Worp, Henk; Kluitenberg, Bas; van Middelkoop, Marienke; Hartgens, Fred; Backx, Frank

    2016-01-01

    Objective: To describe absenteeism and health care utilization (HCU) within 6 weeks after occurrence of running-related injuries (RRIs) among novice runners and to explore differences relating to injury and personal characteristics. Design: Prospective cohort study. Setting: Primary care.

  17. Run Clever - No difference in risk of injury when comparing progression in running volume and running intensity in recreational runners

    DEFF Research Database (Denmark)

    Ramskov, Daniel; Rasmussen, Sten; Sørensen, Henrik

    2018-01-01

    Background/aim: The Run Clever trial investigated if there was a difference in injury occurrence across two running schedules, focusing on progression in volume of running intensity (Sch-I) or in total running volume (Sch-V). It was hypothesised that 15% more runners with a focus on progression...... in volume of running intensity would sustain an injury compared with runners with a focus on progression in total running volume. Methods: Healthy recreational runners were included and randomly allocated to Sch-I or Sch-V. In the first eight weeks of the 24-week follow-up, all participants (n=839) followed...... participants received real-time, individualised feedback on running intensity and running volume. The primary outcome was running-related injury (RRI). Results: After preconditioning a total of 80 runners sustained an RRI (Sch-I n=36/Sch-V n=44). The cumulative incidence proportion (CIP) in Sch-V (reference...

  18. Proximal tibia volumetric bone mineral density is correlated to the magnitude of local acceleration in male long-distance runners

    OpenAIRE

    Dériaz, Olivier; Najafi, Bijan; Ballabeni, Pierluigi; Crettenand, Antoinette; Gobelet, Charles; Aminian, Kamiar; Rizzoli, René; Gremion, Gerald

    2010-01-01

    The beneficial effect of physical exercise on bone mineral density (BMD) is at least partly explained by the forces exerted directly on the bones. Male runners present generally higher BMD than sedentary individuals. We postulated that the proximal tibia BMD is related to the running distance, as well as to the magnitude of the shocks (while running) in male runners. A prospective study (three yearly measurements) included 81 healthy male subjects: 16 sedentary lean subjects, and 3 groups of ...

  19. Instance Analysis for the Error of Three-pivot Pressure Transducer Static Balancing Method for Hydraulic Turbine Runner

    Science.gov (United States)

    Weng, Hanli; Li, Youping

    2017-04-01

    The working principle, process device and test procedure of runner static balancing test method by weighting with three-pivot pressure transducers are introduced in this paper. Based on an actual instance of a V hydraulic turbine runner, the error and sensitivity of the three-pivot pressure transducer static balancing method are analysed. Suggestions about improving the accuracy and the application of the method are also proposed.

  20. THE EFFECT OF STEP RATE MANIPULATION ON FOOT STRIKE PATTERN OF LONG DISTANCE RUNNERS.

    Science.gov (United States)

    Allen, Darrell J; Heisler, Hollie; Mooney, Jennifer; Kring, Richard

    2016-02-01

    Running gait retraining to change foot strike pattern in runners from a heel strike pattern to a non heel- strike pattern has been shown to reduce impact forces and may help to reduce running related injuries. Step rate manipulation above preferred is known to help decrease step length, foot inclination angle, and vertical mass excursion, but has not yet been evaluated as a method to change foot strike pattern. The purpose of this study was to investigate the effect of step rate manipulation on foot strike pattern in shod recreational runners who run with a heel strike pattern. A secondary purpose was to describe the effect of step rate manipulation at specific percentages above preferred on foot inclination angle at initial contact. Forty volunteer runners, who were self-reported heel strikers and had a weekly running mileage of at least 10 miles, were recruited. Runners were confirmed to be heel strikers during the warm up period on the treadmill. The subject's step rate was determined at their preferred running pace. A metronome was used to increase step rate above the preferred step rate by 5%, 10% and 15%. 2D video motion analysis was utilized to determine foot strike pattern and to measure foot inclination angle at initial contact for each step rate condition. There was a statistically significant change in foot strike pattern from a heel strike pattern to a mid-foot or forefoot strike pattern at both 10% and 15% step rates above preferred. Seven of the 40 subjects (17.5%) changed from a heel- strike pattern to a non- heel strike pattern at +10% and 12 of the 40 subjects (30%) changed to a non-heel strike pattern at +15%. Mean foot inclination angle at initial contact showed a statistically significant change (reduction) as step rate increased. Step rate manipulation of 10% or greater may be enough to change foot strike pattern from a heel strike to a mid-foot or forefoot strike pattern in a small percentage of recreational runners who run in traditional

  1. Solar Ultraviolet Radiation Exposure of South African Marathon Runners During Competition Marathon Runs and Training Sessions: A Feasibility Study.

    Science.gov (United States)

    Nurse, Victoria; Wright, Caradee Y; Allen, Martin; McKenzie, Richard L

    2015-01-01

    Marathon runners spend considerable time in outdoor training for and participating in marathons. Outdoor runners may experience high solar ultraviolet radiation (UVR) exposure. South Africa, where running is popular, experiences high ambient solar UVR levels that may be associated with adverse health effects. This feasibility study explores the use of personal dosimeters to determine solar UVR exposure patterns and possible related acute health risks of four marathon runners during marathons and training sessions in Cape Town and Pretoria. Runners running marathons that started early in the day, and that did not exceed 4 hours, yielded low total solar UVR exposure doses (mean 0.093 SED per exposure period run, median 0.088 SED, range 0.062-0.136 SED; average of 16.54% of ambient solar UVR). Training sessions run during early morning and late afternoon presented similar results. Several challenges hindered analysis including accounting for anatomical position of personal dosimeter and natural shade. To assess health risks, hazard quotients (HQs) were calculated using a hypothetical runner's schedule. Cumulative, annual solar UVR exposure-calculated acute health risks were low (HQ = 0.024) for training sessions and moderate (HQ = 4.922) for marathon runs. While these data and calculations are based on 18 person-days, one can measure marathon runners' personal solar UVR exposure although several challenges must be overcome. © 2015 The American Society of Photobiology.

  2. Concurrent speed endurance and resistance training improves performance, running economy and muscle NHE1 in moderately trained runners

    DEFF Research Database (Denmark)

    Skovgaard, Casper; Christensen, Peter Møller; Larsen, Sonni

    2014-01-01

    , content of muscle Na(+)/K(+) pump subunits and MCT4 were unaltered. No changes were observed in CON. The present study demonstrates that SET and HRT, when performed in succession, leads to improvements in both short- and long-term running performance together with improved running economy as well...

  3. Individual adaptation to experimental changes in running speed and step rate during treadmill running in injury-free runners

    DEFF Research Database (Denmark)

    Larsen, Lars Henrik; Kjeldsen, Nikolaj Hørby; Stoklund Pedersen, Daniel

    % velocity with self-selected and 105% step rate and 100% velocity with 105% step rate) and 2 sides (left and right) were analyzed by RM- ANOVA with a Greenhouse-Geisser correction and significance level 0.05 in IBM SPSS version 22.0 Results A 2-way RM-ANOVA including sides (left and right) and conditions (5...

  4. Effects of changing speed on knee and ankle joint load during walking and running.

    Science.gov (United States)

    de David, Ana Cristina; Carpes, Felipe Pivetta; Stefanyshyn, Darren

    2015-01-01

    Joint moments can be used as an indicator of joint loading and have potential application for sports performance and injury prevention. The effects of changing walking and running speeds on joint moments for the different planes of motion still are debatable. Here, we compared knee and ankle moments during walking and running at different speeds. Data were collected from 11 recreational male runners to determine knee and ankle joint moments during different conditions. Conditions include walking at a comfortable speed (self-selected pacing), fast walking (fastest speed possible), slow running (speed corresponding to 30% slower than running) and running (at 4 m · s(-1) ± 10%). A different joint moment pattern was observed between walking and running. We observed a general increase in joint load for sagittal and frontal planes as speed increased, while the effects of speed were not clear in the transverse plane moments. Although differences tend to be more pronounced when gait changed from walking to running, the peak moments, in general, increased when speed increased from comfortable walking to fast walking and from slow running to running mainly in the sagittal and frontal planes. Knee flexion moment was higher in walking than in running due to larger knee extension. Results suggest caution when recommending walking over running in an attempt to reduce knee joint loading. The different effects of speed increments during walking and running should be considered with regard to the prevention of injuries and for rehabilitation purposes.

  5. Lung volumes and maximal respiratory pressures in collegiate swimmers and runners.

    Science.gov (United States)

    Cordain, L; Tucker, A; Moon, D; Stager, J M

    1990-03-01

    To determine whether respiratory muscle strength is related to pulmonary volume differences in athletes and nonathletes, 11 intercollegiate female swimmers, 11 female cross-country runners, and two nonathletic control groups, matched to the athletes in height and age, were evaluated for pulmonary parameters including maximal inspiratory pressure (PImax) and maximal expiratory pressure (PEmax). Swimmers exhibited larger (p less than .05) vital capacities (VC), residual lung volumes (RV), inspiratory capacities (IC), and functional residual capacities (FRC) than both the runners or the controls but no difference (p greater than .05) in either PImax or inspiratory flow (FIV 25%-75%). Timed expiratory volumes (FEV 0.5 and FEV 1.0) were significantly (p less than .05) lower in the swimmers than in the controls. These data suggest that an adaptational growth may be responsible, in part, for the augmented static lung volumes demonstrated in swimmers.

  6. Influence of Working Environment on Fatigue Life Time Duration for Runner Blades of Kaplan Turbines

    Directory of Open Access Journals (Sweden)

    Ana-Maria Budai

    2010-10-01

    Full Text Available The paper present an analytical analyzes refer to influence of working environment on life time duration in service of runner blades of Kaplan turbines. The study are made using only analytical method, the entry dates being obtained from measurements made in situ for a Kaplan turbine. To calculate the maximum number of stress cycles whereupon the runner blades work without any damage it was used an analytical relation known in specialized literatures under the name of Morrow’s relation. To estimate fatigue life time duration will be used a formula obtained from one of most common cumulative damage methodology taking in consideration the real exploitation conditions of a specified Kaplan turbine.

  7. Can GPS be used to detect deleterious progression in training volume among runners?

    DEFF Research Database (Denmark)

    Nielsen, Rasmus Oestergaard; Cederholm, Jens Peter; Buist, Ida

    2013-01-01

    There is a need to ascertain if an association exists between excessive progression in weekly volume and development of running-related injuries (RRI). The purpose of this study was to investigate if GPS can be used to detect deleterious progression in weekly training volume among 60 novice runners...... included in a 10-week prospective study. All participants used GPS to quantify training volume while running. In case of injury, participants attended a clinical examination. The 13 runners who sustained injuries during follow-up had a significantly higher weekly progression in total training volume...... in the week before the injury origin (86% [95% confidence interval: 12.9-159.9], p = 0.026) compared with other weeks. Although not significant, participants with injuries had an increase in weekly training volume of 31.6% compared with a 22.1% increase among the healthy participants. The error of the GPS...

  8. Incidence and determinants of lower extremity running injuries in long distance runners: a systematic review

    Science.gov (United States)

    van Gent, R N; Siem, D; van Middelkoop, M; van Os, A G; Bierma‐Zeinstra, S M A; Koes, B W

    2007-01-01

    The purpose of this study was to present a systematic overview of published reports on the incidence and associated potential risk factors of lower extremity running injuries in long distance runners. An electronic database search was conducted using the PubMed–Medline database. Two observers independently assessed the quality of the studies and a best evidence synthesis was used to summarise the results. The incidence of lower extremity running injuries ranged from 19.4% to 79.3%. The predominant site of these injuries was the knee. There was strong evidence that a long training distance per week in male runners and a history of previous injuries were risk factors for injuries, and that an increase in training distance per week was a protective factor for knee injuries. PMID:17473005

  9. Comparison between recreational male Ironman triathletes and marathon runners.

    Science.gov (United States)

    Gianoli, Daniele; Knechtle, Beat; Knechtle, Patrizia; Barandun, Ursula; Rüst, Christoph Alexander; Rosemann, Thomas

    2012-08-01

    Recent investigations described a personal best marathon time as a predictor variable for an Ironman race time in recreational male Ironman triathletes. Similarities and differences in anthropometry and training were investigated between 83 recreational male Ironman triathletes and 81 recreational male marathoners. Ironman triathletes were significantly taller and had a higher body mass and a higher skin-fold thickness of the calf compared to the marathoners. Weekly training volume in hours was higher in Ironman triathletes. In the Ironman triathletes, percent body fat was related to overall race time and both the split time in cycling and running. The weekly swim kilometres were related to the split time in swimming, and the speed in cycling was related to the bike split time. For the marathoners, the calf skin-fold thickness and running speed during training were related to marathon race time. Although personal best marathon time was a predictor of Ironman race time in male triathletes, anthropometric and training characteristics of male marathoners were different from those of male Ironman triathletes, probably due to training of different muscle groups and metabolic endurance beyond marathon running, as the triathletes are also training for high-level performance in swimming and cycling. Future studies should compare Olympic distance triathletes and road cyclists with Ironman triathletes.

  10. Effects of Surface Inclination on the Vertical Loading Rates and Landing Pattern during the First Attempt of Barefoot Running in Habitual Shod Runners

    OpenAIRE

    An, W.; Rainbow, M. J.; Cheung, R. T. H.

    2015-01-01

    Barefoot running has been proposed to reduce vertical loading rates, which is a risk factor of running injuries. Most of the previous studies evaluated runners on level surfaces. This study examined the effect of surface inclination on vertical loading rates and landing pattern during the first attempt of barefoot running among habitual shod runners. Twenty habitual shod runners were asked to run on treadmill at 8.0?km/h at three inclination angles (0?; +10?; ?10?) with and without their usua...

  11. High-speed Maglev studies in Canada

    International Nuclear Information System (INIS)

    Atherton, D.L.; Eastham, A.R.

    1974-01-01

    This paper reports on Canadian studies of superconducting magnetic levitation and variable-speed linear synchronous motor propulsion for high-speed inter-city guided ground transport. Levitation is obtained by the interaction of vehicle-mounted superconducting magnets and the eddy currents induced in aluminium strip conductors on the guideway. Non-contact propulsion by linear synchronous motor (LSM) is obtained by using vehicle-borne superconducting magnets and powered guideway coils. A suggested guidance scheme uses a flat guideway with 'null-flux' loops overlying the LSM windings. The propulsion magnets interact with the loops and the edges of the levitation strips to provide lateral stabilization. The test facility is a 7.6m wheel, rotating with a peripheral speed of 33m/s. (author)

  12. Predisposing factors to lateral ankle injury in male comrades marathon runners

    Directory of Open Access Journals (Sweden)

    J. Hiemstra

    2009-01-01

    Full Text Available Introduction: More than two million people experience ankle ligament traumaeach year in the United States. Half of these are severe ligament sprains, however verylittle is known about the factors that predispose individuals to these injuries. The purpose of this study, (which was conducted as an undergraduate research project,was to find a correlation between the characteristics of height, weight and limbdominance and lateral ankle ligament injuries. Method: A  retrospective study was conducted on 114 ultra distance runners whoparticipated in the 2006 Comrades Marathon. During race registration, the runners’ height and weight were measuredafter answering a questionnaire regarding their training. Results: 114 runners responded to the questionnaire. From this cohort, 38 (33.3% had sustained previous lateral ankle injuries. Of these 38 injuries, 47.4% of the injuries occurred on the runner’s dominant limb and 36.8% occurred on thenon-dominant side. 15.8% of the runners sustained previous ankle injuries to both ankles. There was a low negative correlation coefficient of 0.24 with regards to weight as a risk factor. This indicated that the power of the correlationwas 5.93%. The study demonstrates that there is no correlation between an increase in weight and an increase in theincidence of ankle injury. The correlation coefficient indicated a low correlation between an increase in height and the incidence of ankle injury. However, the power of the correlation at 18.37% makes inaccurate any attempt to predict the height at which a runner would be at most risk for lateral ankle injury. Conclusion: Height and weight are not risk factors predisposing subjects to lateral ankle injury. In addition, the studyillustrated that there was no effect of limb dominance on the incidence of lateral ankle injury.

  13. Differences in Strike Index Between Treadmill and Aquatic Treadmill Running in Experienced Distance Runners

    OpenAIRE

    Hoover, James Paul, Jr.

    2014-01-01

    Strike index (SI) quantifies how one’s foot contacts the ground at the beginning of the stance phase of gait. SI is reported as a percentage of the total foot length, with lower percentages indicating a more posterior point of contact, while greater percentages indicate a more anterior point of contact along the foot. Differences in SI may be related to running-related injuries, such that experienced distance runners who are rearfoot (posterior) strikers may have approximately twice the rate ...

  14. Gaya Bahasa Dalam Novel Terjemahan Sang Pengejar Layang-layang (the Kite Runner) Karya Khaled Hosseini

    OpenAIRE

    Maya Setia Ekawati, Dian; Sumarwati, Sumarwati; Anindyarini, Atikah

    2012-01-01

    The purpose of this research is : (1) to describes the dominant language of style is use by Khaled Hosseini in the translation novel The Kite Runner, and (2) perception readers againt the used language of style in novel. The sampling technique used was purposive sampling. Data collection techniques used were in-depth interviews and document analysis. Data analysis technique used is the interactive analytical model that includes four components, namely data collection, data reduction, data pre...

  15. Differences in MCT1 A1470T polymorphism prevalence between runners and swimmers.

    Science.gov (United States)

    Ben-Zaken, S; Eliakim, A; Nemet, D; Rabinovich, M; Kassem, E; Meckel, Y

    2015-06-01

    Skeletal muscle is the major producer and user of lactate in the body. Therefore, transport of lactate across cells' membrane is of considerable importance. Lactate transport is mediated by proton-linked monocarboxylate transporter (MCT1). The A1470T polymorphism (rs1049434) in MCT1 gene influences lactate transport, with T allele associated with reduction of lactate transport rate and elevation in blood lactate levels. The aim of the current study was to compare allelic and genotype frequencies of MCT1 A1470T polymorphism among Israeli track-and-field athletes, swimmers, and non-athletes. Genomic DNA was extracted from 173 track-and-field athletes (age 17-50), 80 swimmers (age 16-49), and 128 non-athletes (age 19-29). Track-and-field athletes were assigned to three subgroups: long-distance runners, middle-distance runners, and power event athletes. Swimmers were assigned to two subgroups: long-distance swimmers and short-distance swimmers. Genotyping was performed using polymerase chain reaction. T-allele frequency was significantly higher among long-distance swimmers (45%) compared with long- and middle-distance runners (27% and 30%, respectively; P < 0.01). In addition, T-allele frequency was significantly higher among short-distance swimmers (40%) compared with power event athletes (25%, P < 0.01). Overall, T-allele frequency was significantly higher among swimmers (42%) compared with runners (27%, P < 0.001). More research is needed to clarify whether this polymorphism displays advantage for swimming performance. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. A Survey of Runners' Attitudes Toward and Experiences With Minimally Shod Running.

    Science.gov (United States)

    Cohler, Marissa H; Casey, Ellen

    2015-08-01

    To investigate the characteristics, perceptions, motivating factors, experiences, and injury rates of runners who practice minimally shod running. Survey. web-based questionnaire. Five-hundred sixty-six members of the Chicago Area Runner's Association. A link to a 31-question online survey was e-mailed to members of Chicago Area Runner's Association. Questions covered demographic information, use of minimalist-style running shoes (MSRS), injury rates, and change in pain. Use of MSRS, occurrence or improvement of injury/pain, regions of injury/pain, reasons for or for not using MSRS. One-hundred seventy-five (31%) respondents had practiced minimally shod running, and the most common motivating factor was to decrease injuries and/or pain. Fifty-one respondents (29%) suffered an injury or pain while wearing MSRS, with the most common body part involved being the foot. Fifty-four respondents (31%) had an injury that improved after adopting minimally shod running; the most common area involved was the knee. One-hundred twenty respondents (69%) were still using MSRS. Of those who stopped using MSRS, the main reason was development of an injury or pain. The most common reason that respondents have not tried minimally shod running is a fear of developing an injury. This survey-based study demonstrated that the use of MSRS is common, largely as the result of a perception that they may reduce injuries or pain. Reductions and occurrences of injury/pain with minimally shod running were reported in approximately equal numbers. The most common site of reported injury/pain reduction was the knee, whereas the most common reported site of injury/pain occurrence was the foot. Fear of developing pain or injury is the most common reason runners are reluctant to try minimally shod running. Copyright © 2015 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

  17. Running injuries in novice runners enrolled in different training interventions: a pilot randomized controlled trial.

    Science.gov (United States)

    Baltich, J; Emery, C A; Whittaker, J L; Nigg, B M

    2017-11-01

    The purpose of this trial was to evaluate injury risk in novice runners participating in different strength training interventions. This was a pilot randomized controlled trial. Novice runners (n = 129, 18-60 years old, running experience) were block randomized to one of three groups: a "resistance" strength training group, a "functional" strength training group, or a stretching "control" group. The primary outcome was running related injury. The number of participants with complaints and the injury rate (IR = no. injuries/1000 running hours) were quantified for each intervention group. For the first 8 weeks, participants were instructed to complete their training intervention three to five times a week. The remaining 4 months was a maintenance period. NCT01900262. A total of 52 of the 129 (40%) novice runners experienced at least one running related injury: 21 in the functional strength training program, 16 in the resistance strength training program and 15 in the control stretching program. Injury rates did not differ between study groups [IR = 32.9 (95% CI 20.8, 49.3) in the functional group, IR = 31.6 (95% CI 18.4, 50.5) in the resistance group, and IR = 26.7 (95% CI 15.2, 43.2)] in the control group. Although this was a pilot assessment, home-based strength training did not appear to alter injury rates compared to stretching. Future studies should consider methods to minimize participant drop out to allow for the assessment of injury risk. Injury risk in novice runners based on this pilot study will inform the development of future larger studies investigating the impact of injury prevention interventions. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. Daspsone Induced Peripheral Neuropathy

    Directory of Open Access Journals (Sweden)

    P A Sarojini

    1988-01-01

    Full Text Available A 24 year old lady being treated with 300 mg of dapsone daily for dermatitits herpetiformis, developed weakness and wasting of muscles of feet with claw hand deformity and t drop, 2 months tater. Neurological examination and nerve conduction studies conformed the presence of a peripheral motor neuropathy. Dapsone was discontinued and the patient was treated with cotrimatoxazole, gluten-free diet and supportive therapy. This satisfactorily controlled the dermatological lesion without adversely affecting the resolution of her neuropthy. Symptomatic improvement reported by the patient was confirmed by EMG and nerve conduction studies.

  19. Peripheral ossifying fibroma

    Directory of Open Access Journals (Sweden)

    Ameet Mani

    2010-01-01

    Full Text Available The peripheral ossifying fibroma (POF is an exophytic gingival mass of fibrous connective tissue covered with a surface epithelium associated with the formation of randomly dispersed foci of a mineralized product consisting of bone, cementum-like tissue, or dystrophic calcifications having a recurrent rate of nearly 20%. It is one of the most common reactive gingival lesions, which have often been called by the generic term "epulis." This case report describes the clinical and histopathological findings of POF, its differential diagnosis, and treatment.

  20. Experiences with the hydraulic design of the high specific speed Francis turbine

    International Nuclear Information System (INIS)

    Obrovsky, J; Zouhar, J

    2014-01-01

    The high specific speed Francis turbine is still suitable alternative for refurbishment of older hydro power plants with lower heads and worse cavitation conditions. In the paper the design process of such kind of turbine together with the results comparison of homological model tests performed in hydraulic laboratory of ČKD Blansko Engineering is introduced. The turbine runner was designed using the optimization algorithm and considering the high specific speed hydraulic profile. It means that hydraulic profiles of the spiral case, the distributor and the draft tube were used from a Kaplan turbine. The optimization was done as the automatic cycle and was based on a simplex optimization method as well as on a genetic algorithm. The number of blades is shown as the parameter which changes the resulting specific speed of the turbine between n s =425 to 455 together with the cavitation characteristics. Minimizing of cavitation on the blade surface as well as on the inlet edge of the runner blade was taken into account during the design process. The results of CFD analyses as well as the model tests are mentioned in the paper

  1. Experiences with the hydraulic design of the high specific speed Francis turbine

    Science.gov (United States)

    Obrovsky, J.; Zouhar, J.

    2014-03-01

    The high specific speed Francis turbine is still suitable alternative for refurbishment of older hydro power plants with lower heads and worse cavitation conditions. In the paper the design process of such kind of turbine together with the results comparison of homological model tests performed in hydraulic laboratory of ČKD Blansko Engineering is introduced. The turbine runner was designed using the optimization algorithm and considering the high specific speed hydraulic profile. It means that hydraulic profiles of the spiral case, the distributor and the draft tube were used from a Kaplan turbine. The optimization was done as the automatic cycle and was based on a simplex optimization method as well as on a genetic algorithm. The number of blades is shown as the parameter which changes the resulting specific speed of the turbine between ns=425 to 455 together with the cavitation characteristics. Minimizing of cavitation on the blade surface as well as on the inlet edge of the runner blade was taken into account during the design process. The results of CFD analyses as well as the model tests are mentioned in the paper.

  2. Speed management program plan.

    Science.gov (United States)

    2014-05-01

    Changing public attitudes regarding speeding and speed management will require a comprehensive and concerted effort, involving a wide variety of strategies. This plan identifies six primary focus areas: : A. Data and Data-Driven Approaches, : B. Rese...

  3. Small portable speed calculator

    Science.gov (United States)

    Burch, J. L.; Billions, J. C.

    1973-01-01

    Calculator is adapted stopwatch calibrated for fast accurate measurement of speeds. Single assembled unit is rugged, self-contained, and relatively inexpensive to manufacture. Potential market includes automobile-speed enforcement, railroads, and field-test facilities.

  4. Electric vehicle speed control

    Energy Technology Data Exchange (ETDEWEB)

    Krueger, W.R.; Mc Auliffe, G.N.; Schlageter, G.A.

    1987-06-23

    This patent describes an electric vehicle driven by a DC motor. The vehicle has a field winding, an electric resistance element in circuit with the field winding, a switch in the circuit operative when closed to place. The element in parallel with the field winding weakens the field and increases potential motor speed. Also are relay means for operating the switch, means to determine motor speed, computer means for determining whether the motor speed is increasing or decreasing, and means for operating the relay means to close the switch at a first speed. If the motor speed is increased, it actuates the switch at a second speed lower than the first speed but only if switch has been closed previously and motor speed is decreasing.

  5. Control of impact loading during distracted running before and after gait retraining in runners.

    Science.gov (United States)

    Cheung, Roy T H; An, Winko W; Au, Ivan P H; Zhang, Janet H; Chan, Zoe Y S; MacPhail, Aislinn J

    2018-07-01

    Gait retraining using visual biofeedback has been reported to reduce impact loading in runners. However, most of the previous studies did not adequately examine the level of motor learning after training, as the modified gait pattern was not tested in a dual-task condition. Hence, this study sought to compare the landing peak positive acceleration (PPA) and vertical loading rates during distracted running before and after gait retraining. Sixteen recreational runners underwent a two-week visual biofeedback gait retraining program for impact loading reduction, with feedback on the PPA measured at heel. In the evaluation of PPA and vertical loading rates before and after the retraining, the participants performed a cognitive and verbal counting task while running. Repeated measures ANOVA indicated a significant interaction between feedback and training on PPA (F = 4.642; P = 0.048) but not vertical loading rates (F > 1.953; P > 0.067). Pairwise comparisons indicated a significantly lower PPA and vertical loading rates after gait retraining (P  0.68). Visual feedback after gait retraining reduced PPA and vertical loading rates during distracted running (P  0.36). Gait retraining is effective in lowering impact loading even when the runners are distracted. In dual-task situation, visual biofeedback provided beneficial influence on kinetics control after gait retraining.

  6. Relationship between Achilles tendon length and running performance in well-trained male endurance runners.

    Science.gov (United States)

    Ueno, Hiromasa; Suga, Tadashi; Takao, Kenji; Tanaka, Takahiro; Misaki, Jun; Miyake, Yuto; Nagano, Akinori; Isaka, Tadao

    2018-02-01

    This study aimed to determine the relationship between Achilles tendon (AT) length and running performance, including running economy, in well-trained endurance runners. We also examined the reasonable portion of the AT related to running performance among AT lengths measured in three different portions. The AT lengths at three portions and cross-sectional area (CSA) of 30 endurance runners were measured using magnetic resonance imaging. Each AT length was calculated as the distance from the calcaneal tuberosity to the muscle-tendon junction of the soleus, gastrocnemius medialis (GM AT ), and gastrocnemius lateralis, respectively. These AT lengths were normalized with shank length. The AT CSA was calculated as the average of 10, 20, and 30 mm above the distal insertion of the AT and normalized with body mass. Running economy was evaluated by measuring energy cost during three 4-minutes submaximal treadmill running trials at 14, 16, and 18 km/h, respectively. Among three AT lengths, only a GM AT correlated significantly with personal best 5000-m race time (r=-.376, P=.046). Furthermore, GM AT correlated significantly with energy cost during submaximal treadmill running trials at 14 km/h and 18 km/h (r=-.446 and -.429, respectively, Prunning performance. These findings suggest that longer AT, especially GM AT , may be advantageous to achieve superior running performance, with better running economy, in endurance runners. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  7. GENETIC IDENTIFICATION FOR TUNA AND RAINBOW RUNNER CAPTURE IN NORTH BALI WATERS

    Directory of Open Access Journals (Sweden)

    Gusti Ngurah Permana

    2006-06-01

    Full Text Available Gondol Research Institute for Mariculture identification of tuna and rainbow runner was an objective in this current study. Samples of five species were collected from territorial water of North Bali. The method used in this study was allozyme electrophoresis. The results showed that buffer of CAPM-6 (citric acid aminoprophylmorpholine resulted in a sharp and clear banding pattern. The species could be differentiated in six diagnostic isozyme patterns Idh* (isocitrate dehydrogenase, 6Pgd* (6 phosphogluconate dehydrogenase, Gpi* (glucose phosphate isomerase, Mdh* (malate dehydrogenase, Est* (esterase, and Sp* (sarcoplasmic protein. All species were in Hardy-weinberg equilibrium. Heterozygosities of species were ranged from 0.00 to 0.099. Yellowfin tuna has the highest heterozigosity compared with the other species. Clustering samples according to pairs revealed that genetic distance of Bullet tuna (A. rochei and Eastern little tuna (E. affinis had small value (0.001. By contrast, the largest value was observed between yellowfin tuna, T. albacares and rainbow runner, E. bipunnulata (0.007. This value indicated that Bullet tuna (A. rochei and Eastern little tuna (E. affinis closed relation, while among yellowfin tuna, skipjack tuna, and rainbow runner, were separated phylogenically.

  8. Prevalence, Severity and Potential Nutritional Causes of Gastrointestinal Symptoms during a Marathon in Recreational Runners

    Directory of Open Access Journals (Sweden)

    Jamie N. Pugh

    2018-06-01

    Full Text Available The purpose of the present study was to investigate the prevalence of gastrointestinal symptoms (GIS amongst recreational runners during a marathon race, and potential nutritional factors that may contribute. Recreational runners of the 2017 Liverpool (n = 66 and Dublin (n = 30 marathons were recruited. GIS were reported post-marathon and we considered GIS in the 7 days prior to the marathon and during the marathon using the Gastrointestinal Symptom Rating Scale (GSRS. Nutritional intake was recorded using food diaries for the day before the race, morning of the race, and during the race; 43% of participants reported moderate (≥4 GIS in the 7 days prior to the marathon and 27% reported moderate symptoms during the marathon with most common symptoms being flatulence (16% during training, and nausea (8% during the marathon race. Correlations between all nutritional intake and GIS were not statistically significant (p > 0.05. There were significant correlations between total GIS score (r = 0.510, p < 0.001, upper GIS score (r = 0.346, p = 0.001 and lower GIS score (r = 0.483, p < 0.001 in training and during the marathon. There appears to be a modest prevalence of GIS in recreational runners, in the week prior to a marathon and during marathon running, although there was no association with nutritional intake before or during the race.

  9. Kinetic Risk Factors of Running-Related Injuries in Female Recreational Runners.

    Science.gov (United States)

    Napier, Christopher; MacLean, Christopher L; Maurer, Jessica; Taunton, Jack E; Hunt, Michael A

    2018-05-30

    Our objective was to prospectively investigate the association of kinetic variables with running-related injury (RRI) risk. Seventy-four healthy female recreational runners ran on an instrumented treadmill while 3D kinetic and kinematic data were collected. Kinetic outcomes were vertical impact transient, average vertical loading rate, instantaneous vertical loading rate, active peak, vertical impulse, and peak braking force (PBF). Participants followed a 15-week half-marathon training program. Exposure time (hours of running) was calculated from start of program until onset of injury, loss to follow-up, or end of program. After converting kinetic variables from continuous to ordinal variables based on tertiles, Cox proportional hazard models with competing risks were fit for each variable independently, before analysis in a forward stepwise multivariable model. Sixty-five participants were included in the final analysis, with a 33.8% injury rate. PBF was the only kinetic variable that was a significant predictor of RRI. Runners in the highest tertile (PBF recreational runners and should be considered as a target for gait retraining interventions. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  10. Prevalence, Severity and Potential Nutritional Causes of Gastrointestinal Symptoms during a Marathon in Recreational Runners.

    Science.gov (United States)

    Pugh, Jamie N; Kirk, Ben; Fearn, Robert; Morton, James P; Close, Graeme L

    2018-06-24

    The purpose of the present study was to investigate the prevalence of gastrointestinal symptoms (GIS) amongst recreational runners during a marathon race, and potential nutritional factors that may contribute. Recreational runners of the 2017 Liverpool ( n = 66) and Dublin ( n = 30) marathons were recruited. GIS were reported post-marathon and we considered GIS in the 7 days prior to the marathon and during the marathon using the Gastrointestinal Symptom Rating Scale (GSRS). Nutritional intake was recorded using food diaries for the day before the race, morning of the race, and during the race; 43% of participants reported moderate (≥4) GIS in the 7 days prior to the marathon and 27% reported moderate symptoms during the marathon with most common symptoms being flatulence (16%) during training, and nausea (8%) during the marathon race. Correlations between all nutritional intake and GIS were not statistically significant ( p > 0.05). There were significant correlations between total GIS score ( r = 0.510, p training and during the marathon. There appears to be a modest prevalence of GIS in recreational runners, in the week prior to a marathon and during marathon running, although there was no association with nutritional intake before or during the race.

  11. Increased Circulating Anti-inflammatory Cells in Marathon-trained Runners.

    Science.gov (United States)

    Rehm, K; Sunesara, I; Marshall, G D

    2015-10-01

    Exercise training can alter immune function. Marathon training has been associated with an increased susceptibility to infectious diseases and an increased activity of inflammatory-based diseases, but the precise mechanisms are unknown. The purpose of this study was to compare levels of circulating CD4+  T cell subsets in the periphery of marathon-trained runners and matched non-marathon controls. 19 recreational marathoners that were 4 weeks from running a marathon and 19 demographically-matched healthy control subjects had the percentage of CD4+ T cell subpopulations (T helper 1, T helper 2, T helper 1/T helper 2 ratio, regulatory T cells, CD4+ IL10+, and CD4+ TGFβ+ (Transforming Growth Factor-beta) measured by flow cytometry. Marathon-trained runners had significantly less T helper 1 and regulatory T cells and significantly more T helper 2, CD4+ IL10+, and TGFβ+ cells than the control subjects. The alterations in the percentage of T helper 1 and T helper 2 cells led to a significantly lower T helper 1/T helper 2 ratio in the marathon-trained runners. These data suggest that endurance-based training can increase the number of anti-inflammatory cells. This may be a potential mechanism for the increased incidence of both infectious and inflammatory diseases observed in endurance athletes. © Georg Thieme Verlag KG Stuttgart · New York.

  12. The Effect of Clinical Pilates on Functional Movement in Recreational Runners.

    Science.gov (United States)

    Laws, Anna; Williams, Sean; Wilson, Cassie

    2017-09-01

    Biomechanical imbalances and inefficient functional movements are considered contributing factors to running-related injuries. Clinical Pilates uses a series of exercises focused on retraining normal movement patterns. This study investigated whether a 6-week course of Clinical Pilates improves functional movement and thereby, potentially, reduces the risk of running-related injuries associated with movement dysfunction. A modified functional movement screen was used to analyze the functional movement ability of forty runners. Forty participants completed a 6-week course of Clinical Pilates delivered by a Clinical Pilates instructor. The movement screen was carried out 3 times for each runner: 6 weeks pre-intervention (baseline), within one week pre-intervention (pre) and within one week post-intervention (post). Repeated-measures analysis of variance and post-hoc tests found significant increases in scores between baseline and post (mean±SD; 13.4±2.4 vs. 17.0±1.7, pPilates significantly improves functional movement in recreational runners, and this may lead to a reduction in the risk of running-related injuries. © Georg Thieme Verlag KG Stuttgart · New York.

  13. Nitrogen for growth of stock plants and production of strawberry runner tips

    Directory of Open Access Journals (Sweden)

    Djeimi Isabel Janisch

    2012-01-01

    Full Text Available The objective of this research was to determine growth and dry matter partitioning among organs of strawberry stock plants under five Nitrogen concentrations in the nutrient solution and its effects on emission and growth of runner tips. The experiment was carried out under greenhouse conditions, from September 2010 to March 2011, in a soilless system with Oso Grande and Camino Real cultivars. Nitrogen concentrations of 5.12, 7.6, 10.12 (control, 12.62 and 15.12 mmol L-1 in the nutrient solution were studied in a 5x2 factorial randomised experimental design. All runner tips bearing at least one expanded leaf (patent requested were collected weekly and counted during the growth period. The number of leaves, dry matter (DM of leaves, crown and root, specific leaf area and leaf area index (LAI was determined at the final harvest. Increasing N concentration in the nutrient solution from 5.12 to 15.12 mmol L-1 reduces growth of crown, roots and LAI of strawberry stock plants but did not affect emission and growth of runner tips. It was concluded that for the commercial production of plug plants the optimal nitrogen concentration in the nutrient solution should be 5.12 mmol L-1.

  14. Firm insoles effectively reduce hemolysis in runners during long distance running - a comparative study.

    Science.gov (United States)

    Janakiraman, Kamal; Shenoy, Shweta; Sandhu, Jaspal Singh

    2011-06-09

    Shock absorbing insoles are effective in reducing the magnitude and rate of loading of peak impact forces generated at foot strike during running, whereas the foot impact force during running has been considered to be an important cause of intravascular hemolysis in long distance runners. Objective of this study was to evaluate the intravascular hemolysis during running and compare the effect of two different types of insoles (Soft and Firm) on hemolysis. Twenty male long and middle distance runners volunteered to participate in this study. We selected two insoles (Soft and Firm) according to their hardness level (SHORE 'A' scale). Participants were randomly assigned to the soft insole (group 1) and firm insole (group 2) group with ten athletes in each group. Each athlete completed one hour of running at the calculated target heart rate (60-70%). Venous blood samples were collected before and immediately after running. We measured unconjucated bilirubin (mg/dl), lactate dehydrogenase (μ/ml), hemoglobin (g/l) and serum ferritin (ng/ml) as indicators of hemolysis. Our study revealed a significant increase in the mean values of unconjucated bilirubin (P firm insoles effectively reduces the amount of hemolysis in runners compared to soft insoles.

  15. GenomeRunner web server: regulatory similarity and differences define the functional impact of SNP sets.

    Science.gov (United States)

    Dozmorov, Mikhail G; Cara, Lukas R; Giles, Cory B; Wren, Jonathan D

    2016-08-01

    The growing amount of regulatory data from the ENCODE, Roadmap Epigenomics and other consortia provides a wealth of opportunities to investigate the functional impact of single nucleotide polymorphisms (SNPs). Yet, given the large number of regulatory datasets, researchers are posed with a challenge of how to efficiently utilize them to interpret the functional impact of SNP sets. We developed the GenomeRunner web server to automate systematic statistical analysis of SNP sets within a regulatory context. Besides defining the functional impact of SNP sets, GenomeRunner implements novel regulatory similarity/differential analyses, and cell type-specific regulatory enrichment analysis. Validated against literature- and disease ontology-based approaches, analysis of 39 disease/trait-associated SNP sets demonstrated that the functional impact of SNP sets corresponds to known disease relationships. We identified a group of autoimmune diseases with SNPs distinctly enriched in the enhancers of T helper cell subpopulations, and demonstrated relevant cell type-specificity of the functional impact of other SNP sets. In summary, we show how systematic analysis of genomic data within a regulatory context can help interpreting the functional impact of SNP sets. GenomeRunner web server is freely available at http://www.integrativegenomics.org/ mikhail.dozmorov@gmail.com Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  16. PubRunner: A light-weight framework for updating text mining results.

    Science.gov (United States)

    Anekalla, Kishore R; Courneya, J P; Fiorini, Nicolas; Lever, Jake; Muchow, Michael; Busby, Ben

    2017-01-01

    Biomedical text mining promises to assist biologists in quickly navigating the combined knowledge in their domain. This would allow improved understanding of the complex interactions within biological systems and faster hypothesis generation. New biomedical research articles are published daily and text mining tools are only as good as the corpus from which they work. Many text mining tools are underused because their results are static and do not reflect the constantly expanding knowledge in the field. In order for biomedical text mining to become an indispensable tool used by researchers, this problem must be addressed. To this end, we present PubRunner, a framework for regularly running text mining tools on the latest publications. PubRunner is lightweight, simple to use, and can be integrated with an existing text mining tool. The workflow involves downloading the latest abstracts from PubMed, executing a user-defined tool, pushing the resulting data to a public FTP or Zenodo dataset, and publicizing the location of these results on the public PubRunner website. We illustrate the use of this tool by re-running the commonly used word2vec tool on the latest PubMed abstracts to generate up-to-date word vector representations for the biomedical domain. This shows a proof of concept that we hope will encourage text mining developers to build tools that truly will aid biologists in exploring the latest publications.

  17. Engineering & Performance of DuoTurbo: Microturbine with Counter-Rotating Runners

    Science.gov (United States)

    Biner, D.; Hasmatuchi, V.; Violante, D.; Richard, S.; Chevailler, S.; Andolfatto, L.; Avellan, F.; Münch, C.

    2016-11-01

    Considering the nuclear phase-out strategy of several European countries and the future tendency to promote renewable energies, the exploitation of small hydropower sites (industrial partners. The modular in-line “plug & play” technology requires low investment, reaching economic feasibility with an available power between 5 kW and 25 kW. One stage of the microturbine consists of two axial counter-rotating runners that form a compact independent unit. Each runner of the turbine holds its own rim generator, the DuoTurbo-configuration involving that each hydraulic runner is integral with each electrical rotor. The possibility of stacking several stages in series enables covering quite a wide range of hydraulic power and, thus, recovering a maximum of energy dissipated in release valves of water supply systems. The present work introduces the global concept of the implemented prototype of the DuoTurbo-microturbine, to target a maximal injected power of 5 kW for a discharge of 9 l/s and a head of 24.5 m per stage. The main features of the hydraulic, the mechanical, the electrical and the electronic design are presented. The hydraulic performance is, then, assessed using CFD simulations for the expected operating range. Finally, the performance measurements of the single-stage prototype installed in the hydraulic test rig of the HES-SO Valais//Wallis are presented.

  18. Gait-related intrinsic risk factors for patellofemoral pain in novice recreational runners.

    Science.gov (United States)

    Thijs, Y; De Clercq, D; Roosen, P; Witvrouw, E

    2008-06-01

    To determine prospectively gait-related intrinsic risk factors for patellofemoral pain (PFP) in a population of novice recreational runners. Prospective cohort study. 102 novice recreational runners (89 women) with no history of knee or lower leg complaints. The standing foot posture of the subjects was examined and plantar pressure measurements during running were collected. The subjects then participated in a 10-week "start to run" programme. During this period all sports injuries were registered by a sports medicine physician. The relationship between the standing foot posture and PFP was investigated and gait-related intrinsic risk factors for PFP were determined. The 17 runners who developed PFP exerted a significantly higher vertical peak force underneath the lateral heel and metatarsals 2 and 3. Logistic regression analysis showed that a significantly higher vertical peak force underneath the second metatarsal and shorter time to the vertical peak force underneath the lateral heel were predictors for PFP. No significant evidence was found for an association between an excessively pronated or supinated foot posture and the development of PFP. The findings suggest that an excessive impact shock during heel strike and at the propulsion phase of running may contribute to an increased risk of developing PFP. The hypothesis that persons at risk for PFP show an altered static foot posture in comparison with non-afflicted persons is not supported by the results of this study.

  19. Narratives of Psychosocial Response to Microtrauma Injury among Long-Distance Runners

    Directory of Open Access Journals (Sweden)

    Hayley C. Russell

    2015-07-01

    Full Text Available Athletes with microtrauma or overuse injuries resulting from an accumulation of repeated small forces may differ from athletes with macrotrauma or acute injuries in their psychosocial responses because of the unique challenges presented by these insidious-onset and often chronic injuries. Our purpose was to use narrative inquiry to examine the psychosocial experiences and responses of 10 long-distance runners who had experienced microtrauma injuries. Qualitative data analysis of interview data led to a chronological timeline of the injury experience and an assessment of the meaning attributed to these injury experiences using a variation of Mishler’s core-narrative approach. Participants reported distinct thoughts, feelings, and behaviors during each phase of the injury—pre-injury, injury onset, and outcome. In the pre-injury period, participants indicated specific running-related goals and attributed their injuries to overtraining or a change in training. During the injury onset phase, participants consistently indicated two themes: self-diagnosis and treatment, and not taking time off. Within the outcome phase of injury, participants acknowledged changed training because of the injury, and lessons learned from their injury experiences. The narratives of microtrauma-injured runners revealed psychosocial distress and behavioral tendencies post-injury that have important implications for runners, coaches, and healthcare professionals.

  20. Study on the Pressure Pulsation inside Runner with Splitter Blades in Ultra-High Head Turbine

    International Nuclear Information System (INIS)

    Meng, L; Zhang, S P; Zhou, L J; Wang, Z W

    2014-01-01

    Runners with splitter blades were used widely for the high efficiency and stability. In this paper, the unsteady simulation of an ultra-high head turbine at the best efficiency point, 50% and 75% discharge points were established, to analyze the pressure pulsation in the vaneless space, rotating domain and the draft tube. First of all, runners with different length splitter blades and without splitter blades were compared to learn the efficiency and the pressure distribution on the blade surface. And then the amplitude of the pressure pulsation was analysed. The peak efficiency of the runner with splitter blades is remarkably higher than that of the corresponding impeller without splitter blades. And the efficiency of the turbine is the highest when the length ratio of the splitter blades is 0.75 times the main blades. The pressure pulsation characteristics were also influenced, because the amplitudes of the pulsation induced by the RSI phenomenon were changed as a result of more blades. At last, the best design plan of the length of the splitter blades (length ratio=0.825) was obtained, which improved the pressure pulsation characteristics without significant prejudice to the efficiency

  1. Anthropometric and functional characteristics of Colombian elite long-distance runners

    Directory of Open Access Journals (Sweden)

    Ramírez-Vélez, Robinson

    2015-07-01

    Full Text Available Objective: To evaluate the anthropometric and physical performance characteristics of elite long-distance runners. Methods: A cross-sectional study in 19 male competitive long-distance runners of national level (age 28.2 ± 6.9 years. A total of 24 anthropometric variables were measured according to the International Society for the Advancement of Kinanthropometry (ISAK statements. The Heath-Carter method and the formula proposed by Siri, Matiegka, Jackson and Pollock were used to calculate the somatotype and the body composition, respectively. Ergospirometry VO (2 max, Vertical Jump Test and the Wingate Test were used as functional indicators. Results: Regarding body composition, we found fat mass percentage 13.3 ± 3.2; muscle mass 47.3 ± 2.5%, and body adiposity index 24.1 ± 3.3. Somatotype profile was the mesomorphic-balanced (3.6-4.0-2.1. Mean values of functional tests with their standard deviations were: VO(2 máx (mL•kg-1•min-1 42.6 ± 8.1; anaerobic power 106.0 ± 31.8 kg•s-1, and anaerobic capacity 6501.0 ± 1831.6 K/jul. Conclusion: These results may provide a profile of long-distance runners that can be used as training targets for developing athletes. The results may also provide information for training and tactical emphasis.

  2. Physical activity enhances metabolic fitness independently of cardiorespiratory fitness in marathon runners

    DEFF Research Database (Denmark)

    Laye, M J; Nielsen, M B; Hansen, L S

    2015-01-01

    High levels of cardiovascular fitness (CRF) and physical activity (PA) are associated with decreased mortality and risk to develop metabolic diseases. The independent contributions of CRF and PA to metabolic disease risk factors are unknown. We tested the hypothesis that runners who run consisten......High levels of cardiovascular fitness (CRF) and physical activity (PA) are associated with decreased mortality and risk to develop metabolic diseases. The independent contributions of CRF and PA to metabolic disease risk factors are unknown. We tested the hypothesis that runners who run...... consistently >50 km/wk and/or >2 marathons/yr for the last 5 years have superior metabolic fitness compared to matched sedentary subjects (CRF, age, gender, and BMI). Case-control recruitment of 31 pairs of runner-sedentary subjects identified 10 matched pairs with similar VO2max (mL/min/kg) (similar-VO2max......). The similar-VO2max group was compared with a group of age, gender, and BMI matched pairs who had the largest difference in VO2max (different-VO2max). Primary outcomes that defined metabolic fitness including insulin response to an oral glucose tolerance test, fasting lipids, and fasting insulin were superior...

  3. The Design Method of Axial Flow Runners Focusing on Axial Flow Velocity Uniformization and Its Application to an Ultra-Small Axial Flow Hydraulic Turbine

    Directory of Open Access Journals (Sweden)

    Yasuyuki Nishi

    2016-01-01

    Full Text Available We proposed a portable and ultra-small axial flow hydraulic turbine that can generate electric power comparatively easily using the low head of open channels such as existing pipe conduits or small rivers. In addition, we proposed a simple design method for axial flow runners in combination with the conventional one-dimensional design method and the design method of axial flow velocity uniformization, with the support of three-dimensional flow analysis. Applying our design method to the runner of an ultra-small axial flow hydraulic turbine, the performance and internal flow of the designed runner were investigated using CFD analysis and experiment (performance test and PIV measurement. As a result, the runners designed with our design method were significantly improved in turbine efficiency compared to the original runner. Specifically, in the experiment, a new design of the runner achieved a turbine efficiency of 0.768. This reason was that the axial component of absolute velocity of the new design of the runner was relatively uniform at the runner outlet in comparison with that of the original runner, and as a result, the negative rotational flow was improved. Thus, the validity of our design method has been verified.

  4. Possibilities of rotating drums in ultra-high-speed cinematography

    International Nuclear Information System (INIS)

    Andre, Michel

    A theoretical study shows that it is possible to produce a drum rotating at a peripheral speed of 500m/s. A prototype has actually reached this speed and confirmed the feasibility of the system. It is driven by an electric motor and is made of titanium covered with boron fibres. The main performances to be expected of cameras (whole-image, slit or spectrographic) using such a drum is described [fr

  5. High-speed flow visualization in a pump-turbine under off-design operating conditions

    International Nuclear Information System (INIS)

    Hasmatuchi, V; Roth, S; Botero, F; Avellan, F; Farhat, M

    2010-01-01

    The flow hydrodynamics in a low specific speed radial pump-turbine reduced scale model is experimentally investigated under off-design operating conditions in generating mode. Wall pressure measurements, in the stator, synchronized with high-speed flow visualizations in the vaneless space between the impeller and the guide vanes using air bubbles injection are performed. When starting from the best efficiency point and increasing the runner speed, a significant increase of the pressure fluctuations is observed mainly in channels between wicket gates. The spectral analysis shows a rise of one stall cell, rotating with about 70% of the impeller frequency, at runaway, which further increases as the zero discharge condition is approached. Then a specific image processing technique is detailed and applied to create a synthetic instantaneous view of the flow pattern on the entire guide vanes circumference for an operating point in turbine-brake mode, where backflow and vortices accompany the stall passage.

  6. Vulnerability to exercise addiction, socio-demographic, behavioral and psychological characteristics of runners at risk for eating disorders.

    Science.gov (United States)

    Di Lodovico, Laura; Dubertret, Caroline; Ameller, Aurely

    2018-02-01

    Excessive exercise is frequently associated with eating disorders and may degenerate into exercise addiction. We still don't know whether runners at risk for eating disorders are at risk for exercise addiction. Our aim is to assess: 1) risk for exercise addiction in runners at risk for eating disorders and 2) socio-demographic, behavioral and psychological characteristics distinguishing runners at-risk from not-at-risk for eating disorders. We assessed risk for eating disorders and exercise addiction using the SCOFF questionnaire and the Exercise Addiction Inventory personality traits with the Big-Five Inventory Test, socio-demographic data, eating and training habits in a sample of 154 healthy runners. Twenty five subjects had a score of ≥2 at the SCOFF and were included in the group "at risk for eating disorders". In this group, we found a higher percentage of subjects at risk for exercise addiction (p=0.01) and higher average scores at the Exercise Addiction Inventory (p=0.01) than runners not at risk (N=136). Runners at risk were statistically younger (p=0.03), women (p=0.001), started running to lose weight more often (p=0.03), lost more kilos since affiliation in their running club (p=0.04), and were characterized by neurotic traits using the Big-Five-Inventory Test (p=3.10 -6 ). Screening for exercise addiction and mood disorders could lead to a more accurate management of runners at risk for eating disorders. Identifying vulnerable individuals will facilitate the prevention of eating disorders and preserve the benefits of sport practice. Copyright © 2018. Published by Elsevier Inc.

  7. Short-Term Absenteeism and Health Care Utilization Due to Lower Extremity Injuries Among Novice Runners: A Prospective Cohort Study.

    Science.gov (United States)

    Smits, Dirk-Wouter; Huisstede, Bionka; Verhagen, Evert; van der Worp, Henk; Kluitenberg, Bas; van Middelkoop, Marienke; Hartgens, Fred; Backx, Frank

    2016-11-01

    To describe absenteeism and health care utilization (HCU) within 6 weeks after occurrence of running-related injuries (RRIs) among novice runners and to explore differences relating to injury and personal characteristics. Prospective cohort study. Primary care. One thousand six hundred ninety-six novice runners (18-65 years) participating in a 6-week running program ("Start-to-Run"). Injury characteristics were assessed by weekly training logs and personal characteristics by a baseline questionnaire. Data on absenteeism and HCU were collected using questionnaires at 2 and 6 weeks after the RRI occurred. A total of 185 novice runners (11%) reported an RRI during the 6-week program. Of these injured novice runners, 78% reported absence from sports, whereas only 4% reported absence from work. Fifty-one percent of the injured novice runners visited a health care professional, mostly physical therapists (PTs) rather than physicians. Absenteeism was more common among women than men and was also more common with acute RRIs than gradual-onset RRIs. As regards HCU, both the variety of professionals visited and the number of PT visits were higher among runners with muscle-tendon injuries in the ankle/foot region than among those with other RRIs. Among novice runners sustaining an RRI during a 6-week running program, over three quarters reported short-term absence from sports, whereas absence from work was very limited, and over half used professional health care. Both absence and HCU are associated with injury characteristics. In future running promotion programs (eg in Start-to-Run programs), specific attention should be paid to acute injuries and to muscle-tendon injuries in the ankle/foot region.

  8. Male and female runners demonstrate different sagittal plane mechanics as a function of static hamstring flexibility

    Directory of Open Access Journals (Sweden)

    D. S. Blaise Williams III

    2015-10-01

    Full Text Available ABSTRACTBackground:Injuries to runners are common. However, there are many potential contributing factors to injury. While lack of flexibility alone is commonly related to injury, there are clear differences in hamstring flexibility between males and females.Objective: To compare the effect of static hamstring length on sagittal plane mechanics between male and female runners.Method: Forty subjects (30.0±6.4 years participated and were placed in one of 4 groups: flexible males (n=10, inflexible males (n=10, flexible females (n=10, and inflexible females (n=10. All subjects were free of injury at the time of data collection. Three-dimensional kinematics and kinetics were collected while subjects ran over ground across 2 force platforms. Sagittal plane joint angles and moments were calculated at the knee and hip and compared with a 2-way (sex X flexibility ANOVA (α=0.05.Results: Males exhibited greater peak knee extension moment than females (M=2.80±0.47, F=2.48±0.52 Nm/kg*m, p=0.05 and inflexible runners exhibited greater peak knee extension moment than flexible runners (In=2.83±0.56, Fl=2.44±0.51 Nm/kg*m, p=0.01. For hip flexion at initial contact, a significant interaction existed (p<0.05. Flexible females (36.7±7.4º exhibited more hip flexion than inflexible females (27.9±4.6º, p<0.01 and flexible males (30.1±9.5º, p<0.05. No differences existed for knee angle at initial contact, peak knee angle, peak hip angle, or peak hip moment.Conclusion: Hamstring flexibility results in different mechanical profiles in males and females. Flexibility in the hamstrings may result in decreased moments via active or passive tension. These differences may have implications for performance and injury in flexible female runners.

  9. Drug-induced peripheral neuropathy

    DEFF Research Database (Denmark)

    Vilholm, Ole Jakob; Christensen, Alex Alban; Zedan, Ahmed

    2014-01-01

    Peripheral neuropathy can be caused by medication, and various descriptions have been applied for this condition. In this MiniReview, the term 'drug-induced peripheral neuropathy' (DIPN) is used with the suggested definition: Damage to nerves of the peripheral nervous system caused by a chemical...... substance used in the treatment, cure, prevention or diagnosis of a disease. Optic neuropathy is included in this definition. A distinction between DIPN and other aetiologies of peripheral neuropathy is often quite difficult and thus, the aim of this MiniReview is to discuss the major agents associated...

  10. Speed in Acquisitions

    DEFF Research Database (Denmark)

    Meglio, Olimpia; King, David R.; Risberg, Annette

    2017-01-01

    The advantage of speed is often invoked by academics and practitioners as an essential condition during post-acquisition integration, frequently without consideration of the impact earlier decisions have on acquisition speed. In this article, we examine the role speed plays in acquisitions across...... the acquisition process using research organized around characteristics that display complexity with respect to acquisition speed. We incorporate existing research with a process perspective of acquisitions in order to present trade-offs, and consider the influence of both stakeholders and the pre......-deal-completion context on acquisition speed, as well as the organization’s capabilities to facilitating that speed. Observed trade-offs suggest both that acquisition speed often requires longer planning time before an acquisition and that associated decisions require managerial judgement. A framework for improving...

  11. Region-specific differences in bioenergetic proteins and protein response to acute high fat diet in brains of low and high capacity runner rats.

    Science.gov (United States)

    Gan, Li; Ma, Delin; Li, Min; Yang, Fu-Chen; Rogers, Robert S; Wheatley, Joshua L; Koch, Lauren G; Britton, Steven L; Thyfault, John P; Geiger, Paige C; Stanford, John A

    2018-05-01

    Aerobic capacity is a strong predictor of mortality. Low capacity runner (LCR) rats exhibit reduced mitochondrial function in peripheral organs. A high fat diet (HFD) can worsen metabolic phenotype in LCR rats. Little is known about metabolic changes in the brains of these rats, however. This study examined protein markers of mitochondrial function and metabolism as a function of aerobic running capacity and an acute HFD in four brain regions: the striatum, hippocampus, hypothalamus, and substantia nigra. After 3 days HFD or chow diets, we measured peroxisome proliferator-activated receptor-γ coactivator 1α (PGC1-α), nuclear respiratory factors 1 (Nrf-1), mitochondrial transcription factor A (TFAM), and phosphorylated (activated) AMP-activated protein kinase (p-AMPK) protein levels in the four brain regions. LCR rats exhibited lower levels of mitochondrial proteins (PGC1-α, Nrf-1, TFAM), and greater p-AMPK, in striatum, but not in the other brain regions. Mitochondrial protein levels were greater in HFD LCR striatum, while p-AMPK was lower in this group. Markers of lower mitochondrial biogenesis and increased metabolic demand were limited to the LCR striatum, which nevertheless maintained the capacity to respond to an acute HFD challenge. Copyright © 2018 Elsevier B.V. All rights reserved.

  12. Peripheral degenerative joint diseases

    Directory of Open Access Journals (Sweden)

    Nilzio Antonio da Silva

    2008-03-01

    Full Text Available Osteoarthritis, a degenerative joint disease, is the most commonrheumatic disorder mainly in a geriatric population. Manifestationsare pain, stiffness and functional loss in the affected joint.According to etiology it is classifi ed as primary (or idiopathicand secondary. Some risk factors for disease development aregenetics, race, age, sex, obesity, occupational activities andarticular biomechanics. Pathogenesis is the same for any cause orlocalization, being catabolic alterations, with synthesis, inhibitionand reparing intent of the cartilage matrix. Metalloproteinases andcytokines (IL-1,IL-6,TNF-α actions promote infl ammatory reactionand cartilage degradation. Pain, the most important symptom,does not correlate with radiologic fi ndings. Peripheral osteoarthritisoccurs predominantly in the knee, hip and hand. Diagnosis is basedon clinical features, laboratorial tests and radiological changes.Rheumatological associations’ guidelines for treatment includenon-pharmacologic (education, physiotherapy, assistive devices,and pharmacologic (analgesics, anti-infl ammatory drugs therapyand surgery. Arthroplasty seems to work better than medicines, butshould be used if other treatments have failed.

  13. Incidence of Running-Related Injuries Per 1000 h of running in Different Types of Runners: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Videbæk, Solvej; Bueno, Andreas Moeballe; Nielsen, Rasmus Oestergaard; Rasmussen, Sten

    2015-07-01

    No systematic review has identified the incidence of running-related injuries per 1000 h of running in different types of runners. The purpose of the present review was to systematically search the literature for the incidence of running-related injuries per 1000 h of running in different types of runners, and to include the data in meta-analyses. A search of the PubMed, Scopus, SPORTDiscus, PEDro and Web of Science databases was conducted. Titles, abstracts, and full-text articles were screened by two blinded reviewers to identify prospective cohort studies and randomized controlled trials reporting the incidence of running-related injuries in novice runners, recreational runners, ultra-marathon runners, and track and field athletes. Data were extracted from all studies and comprised for further analysis. An adapted scale was applied to assess the risk of bias. After screening 815 abstracts, 13 original articles were included in the main analysis. Running-related injuries per 1000 h of running ranged from a minimum of 2.5 in a study of long-distance track and field athletes to a maximum of 33.0 in a study of novice runners. The meta-analyses revealed a weighted injury incidence of 17.8 (95% confidence interval [CI] 16.7-19.1) in novice runners and 7.7 (95% CI 6.9-8.7) in recreational runners. Heterogeneity in definitions of injury, definition of type of runner, and outcome measures in the included full-text articles challenged comparison across studies. Novice runners seem to face a significantly greater risk of injury per 1000 h of running than recreational runners.

  14. Analysis of Pressure Fluctuations in a Prototype Pump-Turbine with Different Numbers of Runner Blades in Turbine Mode

    Directory of Open Access Journals (Sweden)

    Deyou Li

    2018-06-01

    Full Text Available In pump-turbines, high pressure fluctuation is one of the crucial instabilities, which is harmful to the stable and effective operation of the entire unit. Extensive studies have been carried out to investigate pressure fluctuations (amplitude and frequency at specific locations. However, limited research was conducted on the distribution of pressure fluctuations in turbine mode in a pump-turbine, as well as the influence of the number of runner blades on pressure fluctuations. Hence, in this study, three dimensional numerical simulations were performed to predict the distribution of pressure fluctuations with different numbers of runner blades in a prototype pump-turbine in turbine mode using the shear stress transport (SST k-ω turbulence model. Three operating points with the same hydraulic head and different mass flow rates were simulated. The distribution of pressure fluctuation components of blade passing frequency and its harmonics in the direction along the whole flow path, as well as along the circumferential direction, was presented. The mass flow rate and number of runner blades have great influence on the distribution of pressure fluctuations, especially at blade passing frequency along circumferential direction. The mass flow rate mainly affects the position of peak pressure fluctuations, while the number of runner blades mainly changes the number of peak pressure fluctuations. Additionally, the number of runner blades influences the dominant frequencies of pressure fluctuations especially in the spiral casing and draft tube.

  15. Design optimization of axial flow hydraulic turbine runner: Part I - an improved Q3D inverse method

    Science.gov (United States)

    Peng, Guoyi; Cao, Shuliang; Ishizuka, Masaru; Hayama, Shinji

    2002-06-01

    With the aim of constructing a comprehensive design optimization procedure of axial flow hydraulic turbine, an improved quasi-three-dimensional inverse method has been proposed from the viewpoint of system and a set of rotational flow governing equations as well as a blade geometry design equation has been derived. The computation domain is firstly taken from the inlet of guide vane to the far outlet of runner blade in the inverse method and flows in different regions are solved simultaneously. So the influence of wicket gate parameters on the runner blade design can be considered and the difficulty to define the flow condition at the runner blade inlet is surmounted. As a pre-computation of initial blade design on S2m surface is newly adopted, the iteration of S1 and S2m surfaces has been reduced greatly and the convergence of inverse computation has been improved. The present model has been applied to the inverse computation of a Kaplan turbine runner. Experimental results and the direct flow analysis have proved the validation of inverse computation. Numerical investigations show that a proper enlargement of guide vane distribution diameter is advantageous to improve the performance of axial hydraulic turbine runner. Copyright

  16. Joint stiffness and running economy during imposed forefoot strike before and after a long run in rearfoot strike runners.

    Science.gov (United States)

    Melcher, Daniel A; Paquette, Max R; Schilling, Brian K; Bloomer, Richard J

    2017-12-01

    Research has focused on the effects of acute strike pattern modifications on lower extremity joint stiffness and running economy (RE). Strike pattern modifications on running biomechanics have mostly been studied while runners complete short running bouts. This study examined the effects of an imposed forefoot strike (FFS) on RE and ankle and knee joint stiffness before and after a long run in habitual rearfoot strike (RFS) runners. Joint kinetics and RE were collected before and after a long run. Sagittal joint kinetics were computed from kinematic and ground reaction force data that were collected during over-ground running trials in 13 male runners. RE was measured during treadmill running. Knee flexion range of motion, knee extensor moment and ankle joint stiffness were lower while plantarflexor moment and knee joint stiffness were greater during imposed FFS compared with RFS. The long run did not influence the difference in ankle and knee joint stiffness between strike patterns. Runners were more economical during RFS than imposed FFS and RE was not influenced by the long run. These findings suggest that using a FFS pattern towards the end of a long run may not be mechanically or metabolically beneficial for well-trained male RFS runners.

  17. Does running with or without diet changes reduce fat mass in novice runners? A 1-year prospective study.

    Science.gov (United States)

    Nielsen, Rasmus O; Videbaek, Solvej; Hansen, Mette; Parner, Erik T; Rasmussen, Sten; Langberg, Henning

    2016-01-01

    The aim of this study was to explore how average weekly running distance, combined with changes in diet habits and reasons to take up running, influence fat mass. Fat mass was assessed by bioelectrical impedance at baseline and after 12 months in 538 novice runners included in a 1-year observational prospective follow-up study. During follow-up, running distance for each participant was continuously measured by GPS while reasons to take up running and diet changes were assessed trough web-based questionnaires. Loss of fat mass was compared between runners covering an average of 5 km or more per week and those running shorter distances. Runners who took up running to lose weight and ran over 5 km per week in average over a one-year period combined with a diet change reduced fat mass by -5.58 kg (95% CI: -8.69; -2.46; Pdiet changes, the mean difference in fat mass between groups was 3.81 kg (95% CI: -5.96; -1.66; Pdiet. An average running distance of more than 5 km per week in runners who took up running to lose weight combined with a targeted diet change seems effective in reducing fat mass over a one-year period among novice runners. Still, randomized controlled trials are needed to better document the effects of self-selected diet changes.

  18. The effectiveness of a preconditioning programme on preventing running-related injuries in novice runners: a randomised controlled trial.

    Science.gov (United States)

    Bredeweg, Steef W; Zijlstra, Sjouke; Bessem, Bram; Buist, Ida

    2012-09-01

    There is no consensus on the aetiology and prevention of running-related injuries in runners. Preconditioning studies among different athlete populations show positive effects on the incidence of sports injuries. A 4-week preconditioning programme in novice runners will reduce the incidence of running-related injuries. Randomised controlled clinical trial; level of evidence, 1. Novice runners (N=432) prepared for a four-mile recreational running event. Participants were allocated to the 4-week preconditioning (PRECON) group (N=211) or the control group (N=221). The PRECON group started a 4-week training programme, prior to the running programme, with walking and hopping exercises. After the 4-week period both groups started a 9-week running programme. In both groups information was registered on running exposure and running-related injuries (RRIs) using an internet-based running log. Primary outcome measure was RRIs per 100 runners. An RRI was defined as any musculoskeletal complaint of the lower extremity or lower back causing restriction of running for at least a week. The incidence of RRIs was 15.2% in the PRECON group and 16.8% in the control group. The difference in RRIs between the groups was not significant (χ(2)=0.161, df=1, p=0.69). This prospective study demonstrated that a 4-week PRECON programme with walking and hopping exercises had no influence on the incidence of RRIs in novice runners.

  19. A MEPS is a MEPS is a MEPS. Comparing Ecodesign and Top Runner schemes for setting product efficiency standards

    Energy Technology Data Exchange (ETDEWEB)

    Siderius, P.J.S. [NL Agency, Croeselaan 15, P.O. Box 8242, 3503 RE Utrecht (Netherlands); Nakagami, H. [Jyukankyo Research Institute, 3-29, Kioi-cho, Chiyoda-ku Tokyo, 102-0094 (Japan)

    2013-02-15

    Both Top Runner in Japan and Ecodesign in the European Union are schemes to set requirements on the energy efficiency (minimum efficiency performance standards, MEPS) of a variety of products. This article provides an overview of the main characteristics and results of both schemes and gives recommendations for improving them. Both schemes contribute significantly to the energy efficiency targets set by the European Commission and the Japanese government. Although it is difficult to compare the absolute levels of the requirements, comparison of the relative improvements and of the savings on household electricity consumption (11 % in Japan, 16 % in the EU) suggest they are in the same range. Furthermore, the time needed to set or review requirements is in both schemes considerable (between 5 and 6 years on average) and the manageability increasingly will become a challenge. The appeal of the Top Runner approach is that the most efficient product (Top Runner) sets the standard for all products at the next target year. Although the Ecodesign scheme includes the elements for a Top Runner approach, it could exploit this principle more explicitly. On the other hand, the Top Runner scheme could benefit by using a real minimum efficiency performance standard instead of a fleet average. This would make the monitoring and enforcement more simple and transparent, and would open the scheme for products where the market situation is less clear.

  20. BWR thermohydraulics simulation on the AD-10 peripheral processor

    International Nuclear Information System (INIS)

    Wulff, W.; Cheng, H.S.; Lekach, S.V.; Mallen, A.N.

    1983-01-01

    This presentation demonstrates the feasibility of simulating plant transients and severe abnormal transients in nuclear power plants at much faster than real-time computing speeds in a low-cost, dedicated, interactive minicomputer. This is achieved by implementing advanced modeling techniques in modern, special-purpose peripheral processors for high-speed system simulation. The results of this demonstration will impact safety analyses and parametric studies, studies on operator responses and control system failures and it will make possible the continuous on-line monitoring of plant performance and the detection and diagnosis of system or component failures

  1. Odontogenic keratocyst: a peripheral variant.

    Science.gov (United States)

    Vij, H; Vij, R; Gupta, V; Sengupta, S

    2011-01-01

    Odontogenic keratocyst, which is developmental in nature, is an intraosseous lesion though on rare occasions it may occur in an extraosseous location. The extraosseous variant is referred to as peripheral odontogenic keratocyst. Though, clinically, peripheral odontogenic keratocyst resembles the gingival cyst of adults, it has histologic features that are pathognomonic of odontogenic keratocyst. This article presents a case of this uncommon entity.

  2. Peripheral dentinogenic ghost cell tumor

    Directory of Open Access Journals (Sweden)

    Sushant S Kamat

    2013-01-01

    Full Text Available Dentinogenic ghost cell tumors (DGCT are uncommon lesions mainly with rare peripheral types. This report presents a case of peripheral DGCT on the left side of the mandibular alveolar ridge of a heavy smoker, a 68-year-old man, with main presenting feature as a mild pain. Submandibular lymphadenopathy and radiological "saucerization" were evident. Differential diagnosis included fibroma, neurofibroma, peripheral ameloblastoma, peripheral odontogenic fibroma, and peripheral giant cell granuloma. Histologically, ameloblastoma-like epithelial elements were seen in association with grouped ghost cells. Proliferating polyhedral cells and stellate reticulum-like cells with various densities were spread over a wide range of the field. The lesion was curetted and after 2 years of follow up, it did not recur.

  3. Amyotrophic Lateral Sclerosis Multiprotein Biomarkers in Peripheral Blood Mononuclear Cells

    OpenAIRE

    Nardo, Giovanni; Pozzi, Silvia; Pignataro, Mauro; Lauranzano, Eliana; Spano, Giorgia; Garbelli, Silvia; Mantovani, Stefania; Marinou, Kalliopi; Papetti, Laura; Monteforte, Marta; Torri, Valter; Paris, Luca; Bazzoni, Gianfranco; Lunetta, Christian; Corbo, Massimo

    2011-01-01

    Background Amyotrophic lateral sclerosis (ALS) is a fatal progressive motor neuron disease, for which there are still no diagnostic/prognostic test and therapy. Specific molecular biomarkers are urgently needed to facilitate clinical studies and speed up the development of effective treatments. Methodology/Principal Findings We used a two-dimensional difference in gel electrophoresis approach to identify in easily accessible clinical samples, peripheral blood mononuclear cells (PBMC), a panel...

  4. Speed and income

    DEFF Research Database (Denmark)

    Fosgerau, Mogens

    2005-01-01

    The relationship between speed and income is established in a microeconomic model focusing on the trade-off between travel time and the risk of receiving a penalty for exceeding the speed limit. This is used to determine when a rational driver will choose to exceed the speed limit. The relationship...... between speed and income is found again in the empirical analysis of a cross-sectional dataset comprising 60,000 observations of car trips. This is used to perform regressions of speed on income, distance travelled, and a number of controls. The results are clearly statistically significant and indicate...... an average income elasticity of speed of 0.02; it is smaller at short distances and about twice as large at the longest distance investigated of 200 km....

  5. The risk of pedestrian collisions with peripheral visual field loss.

    Science.gov (United States)

    Peli, Eli; Apfelbaum, Henry; Berson, Eliot L; Goldstein, Robert B

    2016-12-01

    Patients with peripheral field loss complain of colliding with other pedestrians in open-space environments such as shopping malls. Field expansion devices (e.g., prisms) can create artificial peripheral islands of vision. We investigated the visual angle at which these islands can be most effective for avoiding pedestrian collisions, by modeling the collision risk density as a function of bearing angle of pedestrians relative to the patient. Pedestrians at all possible locations were assumed to be moving in all directions with equal probability within a reasonable range of walking speeds. The risk density was found to be highly anisotropic. It peaked at ≈45° eccentricity. Increasing pedestrian speed range shifted the risk to higher eccentricities. The risk density is independent of time to collision. The model results were compared to the binocular residual peripheral island locations of 42 patients with forms of retinitis pigmentosa. The natural residual island prevalence also peaked nasally at about 45° but temporally at about 75°. This asymmetry resulted in a complementary coverage of the binocular field of view. Natural residual binocular island eccentricities seem well matched to the collision-risk density function, optimizing detection of other walking pedestrians (nasally) and of faster hazards (temporally). Field expansion prism devices will be most effective if they can create artificial peripheral islands at about 45° eccentricities. The collision risk and residual island findings raise interesting questions about normal visual development.

  6. Foot pronation is not associated with increased injury risk in novice runners wearing a neutral shoe : a 1-year prospective cohort study

    NARCIS (Netherlands)

    Nielsen, Rasmus Oestergaard; Buist, Ida; Parner, Erik Thorlund; Nohr, Ellen Aagaard; Sorensen, Henrik; Lind, Martin; Rasmussen, Sten

    Objective To investigate if running distance to first running-related injury varies between foot postures in novice runners wearing neutral shoes. Design A 1-year epidemiological observational prospective cohort study. Setting Denmark. Participants A total of 927 novice runners equivalent to 1854

  7. High speed atom source

    International Nuclear Information System (INIS)

    Hoshino, Hitoshi.

    1990-01-01

    In a high speed atom source, since the speed is not identical between ions and electrons, no sufficient neutralizing effect for ionic rays due to the mixing of the ionic rays and the electron rays can be obtained failing to obtain high speed atomic rays at high density. In view of the above, a speed control means is disposed for equalizing the speed of ions forming ionic rays and the speed of electrons forming electron rays. Further, incident angle of the electron rays and/or ionic rays to a magnet or an electrode is made variable. As a result, the relative speed between the ions and the electrons to the processing direction is reduced to zero, in which the probability of association between the ions and the electrons due to the coulomb force is increased to improve the neutralizing efficiency to easily obtain fine and high density high speed electron rays. Further, by varying the incident angle, a track capable of obtaining an ideal mixing depending on the energy of the neutralized ionic rays is formed. Since the high speed electron rays has such high density, they can be irradiated easily to the minute region of the specimen. (N.H.)

  8. Computer ray tracing speeds.

    Science.gov (United States)

    Robb, P; Pawlowski, B

    1990-05-01

    The results of measuring the ray trace speed and compilation speed of thirty-nine computers in fifty-seven configurations, ranging from personal computers to super computers, are described. A correlation of ray trace speed has been made with the LINPACK benchmark which allows the ray trace speed to be estimated using LINPACK performance data. The results indicate that the latest generation of workstations, using CPUs based on RISC (Reduced Instruction Set Computer) technology, are as fast or faster than mainframe computers in compute-bound situations.

  9. Peripheral Auditory Mechanisms

    CERN Document Server

    Hall, J; Hubbard, A; Neely, S; Tubis, A

    1986-01-01

    How weIl can we model experimental observations of the peripheral auditory system'? What theoretical predictions can we make that might be tested'? It was with these questions in mind that we organized the 1985 Mechanics of Hearing Workshop, to bring together auditory researchers to compare models with experimental observations. Tbe workshop forum was inspired by the very successful 1983 Mechanics of Hearing Workshop in Delft [1]. Boston University was chosen as the site of our meeting because of the Boston area's role as a center for hearing research in this country. We made a special effort at this meeting to attract students from around the world, because without students this field will not progress. Financial support for the workshop was provided in part by grant BNS- 8412878 from the National Science Foundation. Modeling is a traditional strategy in science and plays an important role in the scientific method. Models are the bridge between theory and experiment. Tbey test the assumptions made in experim...

  10. Pressure measurements and high speed visualizations of the cavitation phenomena at deep part load condition in a Francis turbine

    International Nuclear Information System (INIS)

    Yamamoto, K; Müller, A; Favrel, A; Landry, C; Avellan, F

    2014-01-01

    In a hydraulic power plant, it is essential to provide a reliable, sustainable and flexible energy supply. In recent years, in order to cover the variations of the renewable electricity production, hydraulic power plants are demanded to operate with more extended operating range. Under these off-design conditions, a hydraulic turbine is subject to cavitating swirl flow at the runner outlet. It is well-known that the helically/symmetrically shaped cavitation develops at the runner outlet in part load/full load condition, and it gives severe damage to the hydraulic systems under certain conditions. Although there have been many studies about partial and full load conditions, contributions reporting the deep part load condition are limited, and the cavitation behaviour at this condition is not yet understood. This study aims to unveil the cavitation phenomena at deep part load condition by high speed visualizations focusing on the draft tube cone as well as the runner blade channel, and pressure fluctuations associated with the phenomena were also investigated

  11. Peroneal tendinosis as a predisposing factor for the acute lateral ankle sprain in runners.

    Science.gov (United States)

    Ziai, Pejman; Benca, Emir; Wenzel, Florian; Schuh, Reinhard; Krall, Christoph; Auffahrt, Alexander; Hofstetter, Martin; Windhager, Reinhard; Buchhorn, Tomas

    2016-04-01

    A painful episode in the region of the peroneal tendons, within the retromalleolar groove, is a common precipitating event of an acute lateral ankle sprain. A forefoot striking pattern is suspected to cause peroneal tendinosis. The aim of this study is to analyse the role of peroneal tendinosis as a predisposing factor for ankle sprain trauma in runners. Fifty-eight runners who had experienced acute ankle sprain trauma, with pre-existing pain episodes for up to 4 weeks in the region of the peroneal tendons, were assessed clinically. Fractures were excluded by conventional radiography. An magnetic resonance imaging (MRI) scan had been performed within 14 days after the traumatic event and was subsequently evaluated by two experienced radiologists. MRI revealed peroneal tendinosis in 55 patients (95% of the total study population). Peroneus brevis (PB) tendinosis was found in 48 patients (87% of all patients with peroneal tendinosis), and peroneus longus (PL) tendinosis was observed in 42 cases (76%). Thirty-five patients (64%) had combined PB and PL tendinosis. A lesion of the anterior talofibular ligament was found to be the most common ligament injury associated with peroneal tendinosis (29 cases; 53%), followed by a lesion of the calcaneofibular ligament (16 cases; 29%) and a lesion of the posterior tibiofibular ligament (13 cases; 24%). The results of this study reflect the correlation between peroneal tendinosis and ankle sprain trauma. Injuries of one or more ligaments are associated with further complications. A period of rest or forbearance of sports as well as adequate treatment of the peroneal tendinosis is essential to prevent subsequent ankle injuries, especially in runners. Modification of the running technique would also be beneficial. IV.

  12. Application of the allometric scale for the submaximal oxygen uptake in runners and rowers

    Directory of Open Access Journals (Sweden)

    M.P. Tartaruga

    2010-12-01

    Full Text Available Background: The aim of the current study was to determine the allometric exponents for runners and rower’s metabolic cost, while also verifying the relation of performance with and without the allometric application. Methods: Eleven runners (age: 22.3±10.4 years; height: 174±8.8 cm; body mass: 61.7±9.3 kg; maximum oxygen uptake ( •VO2max: 56.3±3.9 ml.kg[sup]-1[/sup].min[sup]-1[/sup] and fifteen rowers (age: 24±5.4 years; height: 185.5±6.5 cm; body mass: 83.5±7.2 kg; •VO2max: 61.2±3.4 ml.kg[sup]-1[/sup].min[sup]-1[/sup] carried out a specific progressive maximum test. The allometric exponent was determined from the logarithmic equation Log y = Log b Log x, where x is the mass, y is the VO2max (l.min[sup]-1[/sup], a is one constant and b is the allometric exponent. The data were analyzed using descriptive and comparative statistics (independent T test of the Student, with p<0.05 (SPSS version 13.0. Results: The allometric exponent of the rowers was 0.70 and that of the runners was 1.00. Significant differences were found between the fat mass percentage, with higher value for rowers, suggesting that this variable may influence the behavior of the allometric exponent and consequently of the basal metabolic rate. Conclusions: Scaling may help in understanding variation in aerobic power and in defining the physiological limitations of work capacity.

  13. Comparison of Achilles Tendon Loading Between Male and Female Recreational Runners

    Directory of Open Access Journals (Sweden)

    Andrew Greenhalgh

    2014-12-01

    Full Text Available Recreational running is an activity with multiple reported health benefits for both sexes, however, chronic injuries caused by excessive and/or repetitive loading of the Achilles tendon are common. Males have been identified as being at an increased risk of suffering an injury to the Achilles tendon and as such, knowledge of differences in loading between the sexes may provide further information to better understand why this is the case. The aim of the current investigation was to determine whether gender differences in the Achilles tendon load exist in recreational runners. Fifteen male (age 26.74 ± 5.52 years, body height 1.80 ± 0.11 m and body mass 74.22 ± 7.27 kg and fifteen female (age 25.13 ± 6.39 years, body height 1.68 ± 0.12 m and body mass 67.12 ± 9.11 kg recreational runners volunteered to take part in the current investigation. Participants completed 10 trials running at 4.0 m·s-1 ±5% striking a force platform (1000 Hz with their right foot. Ankle joint kinematics were synchronously recorded (250 Hz using an optoelectric motion capture system. Ankle joint kinetics were computed using Newton-Euler inverse-dynamics. Net external ankle joint moments were then calculated. To estimate Achilles tendon kinetics the plantarflexion moment calculated was divided by an estimated Achilles tendon moment arm of 0.05 m. Differences in Achilles tendon kinetics were examined using independent sample t-tests (p<0.05. The results indicate that males were associated with significantly (p<0.05 greater Achilles tendon loads than females. The findings from this study support the notion that male recreational runners may be at greater risk of Achilles tendon pathology.

  14. New challenges of Japanese energy efficiency program by Top Runner approach

    International Nuclear Information System (INIS)

    Murakoshi, Chiharu; Nakagami, Hidetoshi; Tsuruda, Masanori; Edamura, Nobuhisa

    2005-01-01

    The Top Runner standards are the key energy efficiency program in Japan. Last year, TVs and VCRs reached the target year for improvement in efficiency, and have improved their efficiencies far more than the original energy savings targets. In order to accelerate energy savings by the Top Runner approach, the Government of Japan is now planning to add new items, and moreover to strengthen the standards for TVs and VCRs. On the other hand, high prices of efficient appliances are considered by many to be the main factor preventing wider diffusion. In order to increase diffusion of efficient appliances by promoting sales, in 2003 the e-Shop Commendation System for retail stores was started, for 'stores that are excellent in promoting diffusion of energy-efficient appliances.' Until then it was quite rare to see products with their e-Mark energy-efficiency labels attached. Moreover, no incentive was given to retail stores to recommend efficient appliances to customers. Under the e-Shop Commendation System, we evaluated comprehensive measures for retail stores, such as the sales ratio of products achieving the standards, percentage of products with e-Mark labels attached, employee education programs, and creation of original posters. As a result of starting the e-Shop Commendation System, e-Mark labels have come to be posted on almost all appliances, original posters have been produced, and sales staffs are receiving instruction in selling points and how to talk with customers. We describe new challenges of the Top Runner program and the contents, evaluation method, and the considerable effect of the e-Shop Commendation System for retail stores

  15. DIFFERENTIAL DIAGNOSIS OF DEEP GLUTEAL PAIN IN A FEMALE RUNNER WITH PELVIC INVOLVEMENT: A CASE REPORT

    Science.gov (United States)

    Podschun, Laura; Kolber, Morey J.; Garcia, Ashley; Rothschild, Carey E.

    2013-01-01

    Background: Gluteal injuries, proximal hamstring injuries, and pelvic floor disorders have been reported in the literature among runners. Some suggest that hip, pelvis, and/or groin injuries occur in 3.3% to 11.5% of long distance runners. The purpose of this case report is to describe the differential diagnosis and treatment approach for a patient presenting with combined hip and pelvic pain. Case description: A 45-year-old female distance runner was referred to physical therapy for proximal hamstring pain that had been present for several months. This pain limited her ability to tolerate sitting and caused her to cease running. Examination of the patient's lumbar spine, pelvis, and lower extremity led to the initial differential diagnosis of hamstring syndrome and ischiogluteal bursitis. The patient's primary symptoms improved during the initial four visits, which focused on education, pain management, trunk stabilization and gluteus maximus strengthening, however pelvic pain persisted. Further examination led to a secondary diagnosis of pelvic floor hypertonic disorder. Interventions to address the pelvic floor led to resolution of symptoms and return to running. Outcomes: Pain level on the Visual Analog Scale decreased from 7/10 to 1/10 over the course of treatment. The patient was able to return to full sport activity and improved sitting tolerance to greater then two hours without significant discomfort. Discussion: This case suggests the interdependence of lumbopelvic and lower extremity kinematics in complaints of hamstring, posterior thigh and pelvic floor disorders. This case highlights the importance of a thorough examination as well as the need to consider a regional interdependence of the pelvic floor and lower quarter when treating individuals with proximal hamstring pain. Level of Evidence: Level 4 PMID:24175132

  16. Preparticipation evaluation of novice, middle-age, long-distance runners.

    Science.gov (United States)

    Aagaard, Philip; Sahlén, Anders; Bergfeldt, Lennart; Braunschweig, Frieder

    2013-01-01

    The purpose of this study was to assess the cardiovascular health and risk profile in middle-age men making an entry to participate for their first time in a long-distance race. Male first-time participants, 45 yr and older, in the world's largest cross-country running race, the Lidingöloppet, were evaluated with a medical history and physical examination, European systematic coronary risk evaluation (SCORE), 12-lead ECG, echocardiography, and blood tests. Further diagnostic workup was performed when clinically indicated. Of 265 eligible runners, 153 (58%, age 51 ± 5 yr) completed the study. Although the 10-yr fatal cardiovascular event risk was low (SCORE, 1%; interquartile range, 0%-1%), mild abnormalities were common, for example, elevated blood pressure (19%), left ventricular hypertrophy (6%), and elevated LDL cholesterol (5%). ECG changes compatible with the "athlete's heart" were present in 82%, for example, sinus bradycardia (61%) and/or early repolarization (32%). ECG changes considered training unrelated were found in 24%, for example, prolonged QTc-interval (13%), left axis deviation (5.3%), and left atrial enlargement (4%). In 14 runners (9%), additional diagnostic workup was clinically motivated, and 4 runners (2%) were ultimately discouraged from vigorous exercise because of QTc intervals >500 ms (n = 2), symptomatic atrioventricular block (n = 1), and cardiac tumor (n = 1). The physician examination and the ECG identified 12 of the 14 participants requiring further evaluation. Cardiovascular evaluation of middle-age men, including a physician examination and a 12-lead ECG, appears useful to identify individuals requiring further testing before vigorous exercise. The additional yield of routine echocardiography was small.

  17. 10-20-30 training increases performance and lowers blood pressure and VEGF in runners.

    Science.gov (United States)

    Gliemann, Lasse; Gunnarsson, Thomas P; Hellsten, Ylva; Bangsbo, Jens

    2015-10-01

    The present study examined the effect of training by the 10-20-30 concept on performance, blood pressure (BP), and skeletal muscle angiogenesis as well as the feasibility of completing high-intensity interval training in local running communities. One hundred sixty recreational runners were divided into either a control group (CON; n = 28), or a 10-20-30 training group (10-20-30; n = 132) replacing two of three weekly training sessions with 10-20-30 training for 8 weeks and performance of a 5-km run (5-K) and BP was measured. VO2max was measured and resting muscle biopsies were taken in a subgroup of runners (n = 18). 10-20-30 improved 5-K time (38 s) and lowered systolic BP (2 ± 1 mmHg). For hypertensive subjects in 10-20-30 (n = 30), systolic and diastolic BP was lowered by 5 ± 4 and 3 ± 2 mmHg, respectively, which was a greater reduction than in the non-hypertensive subjects (n = 102). 10-20-30 increased VO2max but did not influence muscle fiber area, distribution or capillarization, whereas the expression of the pro-angiogenic vascular endothelial growth factor (VEGF) was lowered by 22%. No changes were observed in CON. These results suggest that 10-20-30 training is an effective and easily implemented training intervention improving endurance performance, VO2max and lowering BP in recreational runners, but does not affect muscle morphology and reduces muscle VEGF. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. Predictors of running-related injuries in novice runners enrolled in a systematic training program: a prospective cohort study.

    Science.gov (United States)

    Buist, Ida; Bredeweg, Steef W; Lemmink, Koen A P M; van Mechelen, Willem; Diercks, Ron L

    2010-02-01

    The popularity of running is still growing. As participation increases, running-related injuries also increase. Until now, little is known about the predictors for injuries in novice runners. Predictors for running-related injuries (RRIs) will differ between male and female novice runners. Cohort study; Level of evidence, 2. Participants were 532 novice runners (226 men, 306 women) preparing for a recreational 4-mile (6.7-km) running event. After completing a baseline questionnaire and undergoing an orthopaedic examination, they were followed during the training period of 13 weeks. An RRI was defined as any self-reported running-related musculoskeletal pain of the lower extremity or back causing a restriction of running for at least 1 week. Twenty-one percent of the novice runners had at least one RRI during follow-up. The multivariate adjusted Cox regression model for male participants showed that body mass index (BMI) (hazard ratio [HR], 1.15; 95% confidence interval [CI], 1.05-1.26), previous injury in the past year (HR, 2.7; 95% CI, 1.36-5.55), and previous participation in sports without axial load (HR, 2.05; 95% CI, 1.03-4.11) were associated with RRI. In female participants, only navicular drop (HR, 0.85; 95% CI, 0.75-0.97) remained a significant predictor for RRI in the multivariate Cox regression modeling. Type A behavior and range of motion (ROM) of the hip and ankle did not affect risk. Male and female novice runners have different risk profiles. Higher BMI, previous injury, and previous sports participation without axial loading are important predictors for RRI in male participants. Further research is needed to detect more predictors for female novice runners.

  19. Pacing Strategy, Muscle Fatigue and Technique in 1500m Speed Skating and Cycling Time-Trials

    NARCIS (Netherlands)

    Stoter, Inge K; MacIntosh, Brian R; Fletcher, Jared R; Pootz, Spencer; Zijdewind, Inge; Hettinga, Florentina J

    2016-01-01

    PURPOSE: To evaluate pacing behavior and peripheral and central contributions to muscle fatigue in 1500m speed skating and cycling time-trials, when a faster or slower start is instructed. METHODS: Nine speed skaters and nine cyclists, all competing at regional or national level, performed two 1500m

  20. Cardiovascular responses to static exercise in distance runners and weight lifters

    Science.gov (United States)

    Longhurst, J. C.; Kelly, A. R.; Gonyea, W. J.; Mitchell, J. H.

    1980-01-01

    Three groups of athletes including long-distance runners, competitive and amateur weight lifters, and age- and sex-matched control subjects have been studied by hemodynamic and echocardiographic methods in order to determine the effect of the training programs on the cardiovascular response to static exercise. Blood pressure, heart rate, and double product data at rest and at fatigue suggest that competitive endurance (dynamic exercise) training alters the cardiovascular response to static exercise. In contrast to endurance exercise, weight lifting (static exercise) training does not alter the cardiovascular response to static exercise: weight lifters responded to static exercise in a manner very similar to that of the control subjects.

  1. Optimization of the Runner for Extremely Low Head Bidirectional Tidal Bulb Turbine

    Directory of Open Access Journals (Sweden)

    Yongyao Luo

    2017-06-01

    Full Text Available This paper presents a multi-objective optimization procedure for bidirectional bulb turbine runners which is completed using ANSYS Workbench. The optimization procedure is able to check many more geometries with less manual work. In the procedure, the initial blade shape is parameterized, the inlet and outlet angles (β1, β2, as well as the starting and ending wrap angles (θ1, θ2 for the five sections of the blade profile, are selected as design variables, and the optimization target is set to obtain the maximum of the overall efficiency for the ebb and flood turbine modes. For the flow analysis, the ANSYS CFX code, with a SST (Shear Stress Transport k-ω turbulence model, has been used to evaluate the efficiency of the turbine. An efficient response surface model relating the design parameters and the objective functions is obtained. The optimization strategy was used to optimize a model bulb turbine runner. Model tests were carried out to validate the final designs and the design procedure. For the four-bladed turbine, the efficiency improvement is 5.5% in the ebb operation direction, and 2.9% in the flood operation direction, as well as 4.3% and 4.5% for the three-bladed turbine. Numerical simulations were then performed to analyze the pressure pulsation in the pressure and suction sides of the blade for the prototype turbine with optimal four-bladed and three-bladed runners. The results show that the runner rotational frequency (fn is the dominant frequency of the pressure pulsations in the blades for ebb and flood turbine modes, and the gravitational effect, rather than rotor-stator interaction (RSI, plays an important role in a low head horizontal axial turbine. The amplitudes of the pressure pulsations on the blade side facing the guide vanes varies little with the water head. However, the amplitudes of the pressure pulsations on the blade side facing the diffusion tube linearly increase with the water head. These results could provide

  2. Oxygen Consumption of Elite Distance Runners on an Anti-Gravity Treadmill®

    Directory of Open Access Journals (Sweden)

    David K.P. McNeill, John R. Kline, Hendrick D. de Heer, J. Richard Coast

    2015-06-01

    Full Text Available Lower body positive pressure (LBPP, or ‘anti-gravity’ treadmills® have become increasingly popular among elite distance runners. However, to date, few studies have assessed the effect of body weight support (BWS on the metabolic cost of running among elite runners. This study evaluated how BWS influenced the relationship between velocity and metabolic cost among 6 elite male distance runners. Participants ran three- 16 minute tests consisting of 4 stages of 4 minutes at 8, 7, 6 and 5 min·mile−1 pace (3.35, 3.84, 4.47 and 5.36 m·s−1, while maintaining an aerobic effort (Respiratory Exchange Ratio ≤1.00. One test was run on a regular treadmill, one on an anti-gravity treadmill with 40% BWS and one with 20% BWS being provided. Expired gas data were collected and regression equations used to determine and compare slopes. Significant decreases in oxygen uptake (V̇O2 were found with each increase in BWS (p < 0.001. At 20% BWS, the average decrease in net VO2 was greater than proportional (34%, while at 40% BWS, the average net reduction in VO2 was close to proportional (38%. Across velocities, the slope of the relationship between VO2 and velocity (ΔV̇O2/Δv was steeper with less support. The slopes at both the 20% and 40% BWS conditions were similar, especially when compared to the regular treadmill. Variability in VO2 between athletes was much greater on the LBPP treadmill and was greater with increased levels of BWS. In this study we evaluated the effect of body weight support on V̇O2 among elite distance runners. We have shown that oxygen uptake decreased with support, but not in direct proportion to that support. Further, because of the high variability in oxygen uptake between athletes on the LBPP treadmill, prediction equations may not be reliable and other indicators (heart rate, perceived exertion or directly measured oxygen uptake should be used to guide training intensity when training on the LBPP treadmill.

  3. The reliability of running economy expressed as oxygen cost and energy cost in trained distance runners.

    Science.gov (United States)

    Shaw, Andrew J; Ingham, Stephen A; Fudge, Barry W; Folland, Jonathan P

    2013-12-01

    This study assessed the between-test reliability of oxygen cost (OC) and energy cost (EC) in distance runners, and contrasted it with the smallest worthwhile change (SWC) of these measures. OC and EC displayed similar levels of within-subject variation (typical error < 3.85%). However, the typical error (2.75% vs 2.74%) was greater than the SWC (1.38% vs 1.71%) for both OC and EC, respectively, indicating insufficient sensitivity to confidently detect small, but meaningful, changes in OC and EC.

  4. Biomechanical factors associated with running economy and performance of elite Kenyan distance runners: A systematic review.

    Science.gov (United States)

    Tawa, Nassib; Louw, Quinette

    2018-01-01

    Running economy (RE) is a determinant of performance in endurance sports and is a complex multi-factorial measure which reflects the combined functioning of bio-mechanical, neuro-muscular, metabolic and cardio-respiratory factors some of which are hereditary or adapt to coaching. Kenyan distance runners have dominated major global events with their unmatched performance for decades and this phenomenon has prompted several investigations aimed at establishing possible factors associated with their performance. This systematic review was aimed at establishing up-to date quantitative synthesis of evidence on biomechanical factors associated with running economy and performance of elite Kenyan distance runners and to provide an algorithm for future research and coaching strategies. A comprehensive electronic search was conducted through June 2017. Quality appraisal was independently done by both reviewers using the STROBE checklist. Descriptive summaries and tables were used to illustrate biomechanical outcomes, mean differences and confidence intervals. Evidence from reviewed studies was graded according to the Australian National Health and Medical Research Council (NHMRC) hierarchy for aetiological factors and meta-analysis was performed where applicable. Eight cross-sectional studies were included. The overall methodological score was moderate (58%). Elite Kenyan distance runners have significant longer gastroc-Achilles tendons compared to their counterparts while their shank length is not significantly longer. There is no certainty of evidence regarding the association between their characteristic unique profile of tall and slender bodies, low BMI and low body mass, short ground contact and flight times, greater forward lean torso and faster and greater forward leg swing with RE and performance. Our findings presents evidence on biomechanical factors associated with RE and performance of elite Kenyan distance runners. Despite these findings, there are a number of

  5. Endurance in speed skating

    NARCIS (Netherlands)

    Kuper, G.H.; Sterken, E.

    2002-01-01

    We analyse the development of world records speed skating from 1893 to 2000 for bothmen and women. The historical data show that it is likely that the relation betweenskating speed and distance of the various events is non-linear and converges to a limitvalue. We pay special attention to technical

  6. Endurance in speed skating

    NARCIS (Netherlands)

    Kuper, Gerard H.; Sterken, Elmer

    2001-01-01

    We analyse the development of world records speed skating from 1893 to 2000 for both men and women. The historical data show that it is likely that the relation between skating speed and distance of the various events is non-linear and converges to a limit value. We pay special attention to

  7. Effects of Marathon Running on Aerobic Fitness and Performance in Recreational Runners One Week after a Race

    OpenAIRE

    Takayama, Fuminori; Aoyagi, Atsushi; Shimazu, Wataru; Nabekura, Yoshiharu

    2017-01-01

    It is not clear whether or not recreational runners can recover aerobic fitness and performance within one week after marathon running. This study aimed to investigate the effects of running a marathon race on aerobic fitness and performance one week later. Eleven recreational runners (six men, five women) completed the race in 3 h 36 min 20 s ± 41 min 34 s (mean ± standard deviation). Before and 7 days after the race, they performed a treadmill running test. Perceived muscle soreness was ass...

  8. Effectiveness of Motorcycle speed controlled by speed hump

    Directory of Open Access Journals (Sweden)

    Pornsiri Urapa

    2014-09-01

    Full Text Available Speed humps are one of the traffic calming measures widely accepted to control vehicle speed in the local road. Humps standards from the western countries are designed mainly for the passenger car. This study, therefore, aims to reveal the effectiveness of speed hump to control the motorcycle speed. This study observes the free-flow speed of the riders at the total of 20 speed bumps and humps. They are 0.3-14.8 meter in width and 5-18 centimeter in height. The results reveal that the 85th percentile speeds reduce 15-65 percent when crossing the speed bumps and speed humps. Besides, this study develops the speed model to predict the motorcycle mean speed and 85th percentile speed. It is found that speed humps follow the ITE standard can control motorcycle crossing speeds to be 25-30 Kph which are suitable to travel on the local road.

  9. Peripheral T-Cell Lymphoma

    Science.gov (United States)

    ... Non-Hodgkin Lymphoma Peripheral T-Cell Lymphoma Primary Central Nervous System Lymphoma T-Cell Lymphoma Transformed Mycosis Fungoides Waldenstrom Macroglobulinemia Young Adult Lymphoma Overview Treatment Options Relapsed/Refractory Long-term ...

  10. Network node for peripheral sharing

    International Nuclear Information System (INIS)

    Bobbitt, J.; Johnson, M.

    1977-01-01

    A module which enables several independent computer systems to share the peripherals (graphics display and line printer) of a PDP-11 computer is described. The module requires no software support in the PDP-11

  11. A reference Pelton turbine - High speed visualization in the rotating frame

    Science.gov (United States)

    Solemslie, Bjørn W.; Dahlhaug, Ole G.

    2016-11-01

    To enable a detailed study the flow mechanisms effecting the flow within the reference Pelton runner designed at the Waterpower Laboratory (NTNLT) a flow visualization system has been developed. The system enables high speed filming of the hydraulic surface of a single bucket in the rotating frame of reference. It is built with an angular borescopes adapter entering the turbine along the rotational axis and a borescope embedded within a bucket. A stationary high speed camera located outside the turbine housing has been connected to the optical arrangement by a non-contact coupling. The view point of the system includes the whole hydraulic surface of one half of a bucket. The system has been designed to minimize the amount of vibrations and to ensure that the vibrations felt by the borescope are the same as those affecting the camera. The preliminary results captured with the system are promising and enable a detailed study of the flow within the turbine.

  12. THERE ARE NO BIOMECHANICAL DIFFERENCES BETWEEN RUNNERS CLASSIFIED BY THE FUNCTIONAL MOVEMENT SCREEN

    Science.gov (United States)

    de Oliveira, Rodrigo Ribeiro; Chaves, Shalimá Figueirêdo; Lima, Yuri Lopes; Bezerra, Márcio Almeida; Leão Almeida, Gabriel Peixoto

    2017-01-01

    Background Running has been one of the main choices of physical activity in people seeking an active lifestyle. The Functional Movement Screen (FMS™) is a screening tool that aims to discern movement competency. Purpose The purposes of this study were to compare biomechanical characteristics between two groups rated using the composite FMS™ score, and to analyze the influence of specific individual tests. The hypothesis was that the group that scored above 14 would demonstrate better performance on biomechanical tests than the group that scored below 14. Study Design Cross-Sectional Study. Methods Runners were screened using the FMS™ and were dichotomized into groups based on final score: Functional, where the subjects scored a 14 or greater (G≥14, n = 16) and dysfunctional, when the subjects scored less than 14 (G in flexibility, muscle strength, knee dynamic valgus, or myoelectric response time of the transversus abdominis and long fibular muscles. Index of asymmetry (IS) of global stability was 3.26 ± 26.79% in G≥14 and 31.72 ± 52.69% in GIn-line lunge and active straight-leg raise tests showed no significant difference between the groups (p > 0.05). Conclusions Overall, there were no biomechanical differences between the groups of runners as classified by the FMS™. In addition, in-line lunge and active strength-leg raise tests did not influence on the FMS™ final score. Level of Evidence 2b PMID:28900569

  13. Sprinting, Change of Direction Ability and Horizontal Jump Performance in Youth Runners According to Gender

    Directory of Open Access Journals (Sweden)

    Yanci Javier

    2017-12-01

    Full Text Available The purpose of the study was to assess straight sprinting, change of direction ability and horizontal jump performance in youth runners according to age and gender. Two hundred and fifty-five youth runners (116 boys and 139 girls participated in this study. The athletes were divided according to their age into five groups: under 8 yr (U8, under 10 yr (U10, under 12 yr (U12, under 14 yr (U14 and under 16 yr (U16. Significant differences (p 0.05, d = 0.29-1.17 between U14 and U16 were observed in any of the tests. With regard to age and gender, in U8 and U10 groups there were no significant differences (p > 0.05, d = 0.02-0.76 between boys and girls in any test. However, in U12 and U14 groups, significant gender differences (p < 0.05, d = 0.85-1.24 were found in the MAT. Likewise, the boys obtained better results than girls in the horizontal jump tests (p < 0.05, d = 1.01-1.26. After the classification by age, some differences were observed between both genders, depending on the fitness variable evaluated.

  14. Analysis of a pico tubular-type hydro turbine performance by runner blade shape using CFD

    Science.gov (United States)

    Park, J. H.; Lee, N. J.; Wata, J. V.; Hwang, Y. C.; Kim, Y. T.; Lee, Y. H.

    2012-11-01

    There has been a considerable interest recently in the topic of renewable energy. This is primarily due to concerns about environmental impacts of fossil fuels. Moreover, fluctuating and rising oil prices, increase in demand, supply uncertainties and other factors have led to increased calls for alternative energy sources. Small hydropower, among other renewable energy sources, has been evaluated to have adequate development value because it is a clean, renewable and abundant energy resource. In addition, small hydropower has the advantage of low cost development by using rivers, agricultural reservoirs, sewage treatment plants, waterworks and water resources. The main concept of the tubular-type hydro turbine is based on the difference in water pressure levels in pipe lines, where the energy which was initially wasted by using a reducing valve at the pipeline of waterworks, is collected by turbine in the hydro power generator. In this study, in order to acquire the performance data of a pico tubular-type hydro turbine, the output power, head and efficiency characteristics by different runner blade shapes are examined. The pressure and velocity distributions with the variation of guide vane and runner vane angle on turbine performance are investigated by using a commercial CFD code.

  15. Achilles tendon adaptation in cross-country runners across a competitive season.

    Science.gov (United States)

    Stanley, L E; Lucero, A; Mauntel, T C; Kennedy, M; Walker, N; Marshall, S W; Padua, D A; Berkoff, D J

    2018-01-01

    Ultrasound tissue characterization (UTC) is an imaging tool used to quantify tendon structural integrity. UTC has quantified Achilles tendon (AT) acute response to load in athletes; however, AT response to cumulative load over a season is unknown. The purpose of this study was to evaluate AT response across a four-month competitive season in collegiate cross-country (XC) runners. Participants (n=21; male=9, female=12; age=19.8±1.2 years; height=171.9±8.9 cm; weight=60.2±8.5 kg) were imaged using the UTC device with a 10-MHz linear-array transducer mounted in a tracking device. The device captures images at 0.2 mm intervals along the AT. UTC algorithms quantified the stability of pixel brightness over every 17 contiguous transverse images into four echo types (I-IV). A total of 168 scans (n=21, bilateral limbs) were performed monthly across the four-month season (Aug=M1, Sep=M2, Oct=M3, Nov=M4). Echo-type percentages (%) were calculated from each scan. Generalized estimating equations (GEE) linear regression models evaluated echo-type % change (β) over the season (M1=reference). Type I increased from M1 to M4 (β=9.10, Presilience to a competitive season of repetitive loading in highly trained runners. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. Primary and secondary exercise dependence in a community-based sample of road race runners.

    Science.gov (United States)

    Cook, Brian; Karr, Trisha M; Zunker, Christie; Mitchell, James E; Thompson, Ron; Sherman, Roberta; Crosby, Ross D; Cao, Li; Erickson, Ann; Wonderlich, Stephen A

    2013-10-01

    The purpose of our study was to examine exercise dependence (EXD) in a large community-based sample of runners. The secondary purpose of this study was to examine differences in EXD symptoms between primary and secondary EXD. Our sample included 2660 runners recruited from a local road race (M age = 38.78 years, SD = 10.80; 66.39% women; 91.62% Caucasian) who completed all study measures online within 3 weeks of the race. In this study, EXD prevalence was lower than most previously reported rates (gamma = .248, p < .001) and individuals in the at-risk for EXD category participated in longer distance races, F(8,1) = 14.13, p = .01, partial eta squared = .05. Group differences were found for gender, F(1,1921) 8.08, p = .01, partial eta squared = .004, and primary or secondary group status, F(1,1921) 159.53, p = .01, partial eta squared = .077. Implications of primary and secondary EXD differences and future research are discussed.

  17. Effects of repetitive training at low altitude on erythropoiesis in 400 and 800 m runners.

    Science.gov (United States)

    Frese, F; Friedmann-Bette, B

    2010-06-01

    Classical altitude training can cause an increase in total hemoglobin mass (THM) if a minimum "dose of hypoxia" is reached (altitude >or=2,000 m, >or=3 weeks). We wanted to find out if repetitive exposure to mild hypoxia during living and training at low altitude (training camps at low altitude interspersed by 3 weeks of sea-level training and at the same time points in a control group (CG) of 5 well-trained runners. EPO, sTfR and ferritin were also repeatedly measured during the altitude training camps. Repeated measures ANOVA revealed significant increases in EPO- and sTfR-levels during both training camps and a significant decrease in ferritin indicating enhanced erythropoietic stimulation during living and training at low altitude. Furthermore, significant augmentation of THM by 5.1% occurred in the course of the 2 altitude training camps. In conclusion, repetitive living and training at low altitude leads to a hypoxia-induced increase in erythropoietic stimulation in elite 400 m and 800 m runners and, apparently, might also cause a consecutive augmentation of THM.

  18. Whey Protein Improves Marathon-Induced Injury and Exercise Performance in Elite Track Runners.

    Science.gov (United States)

    Huang, Wen-Ching; Chang, Yung-Cheng; Chen, Yi-Ming; Hsu, Yi-Ju; Huang, Chi-Chang; Kan, Nai-Wen; Chen, Sheng-Shih

    2017-01-01

    Whey protein has been widely applied to athletes and the fitness field for muscle growth and performance improvement. Limited studies focused on the beneficial effects of whey on aerobic exercise according to biochemical assessments. In the current study, 12 elite male track runners were randomly assigned to whey and maltodextrin groups for 5 weeks' supplementation. The aim of this study was to investigate the effect of whey protein on physiological adaptions and exercise performance. During this period, three time points (pre-, post-, and end-test) were used to evaluate related biochemical parameters, body composition, and performance. The post-test was set 1 day after a marathon for injury status evaluation and the end-test was also assessed after 1-week recovery from endurance test. The results showed that the whey group exhibited significantly lower aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and creatine kinase indicators after the marathon (post-test), as well as at the end-test ( p <0.016). The endurance performance in twelve-minute walk/run was also significantly elevated ( p <0.012) possibly due to an increase in the muscle mass and amelioration of exercise injuries. In the current study, we demonstrated that whey protein can also be used for aerobic exercise for better physiological adaptation, in addition to resistance training. Whey protein could be also a potential nutrient supplement with a variety of benefits for amateur runners.

  19. Cavitation erosion - corrosion behaviour of ASTM A27 runner steel in natural river water

    International Nuclear Information System (INIS)

    Tôn-Thât, L

    2014-01-01

    Cavitation erosion is still one of the most important degradation modes in hydraulic turbine runners. Part of researches in this field focuses on finding new materials, coatings and surface treatments to improve the resistance properties of runners to this phenomenon. However, only few studies are focused on the deleterious effect of the environment. Actually, in some cases a synergistic effect between cavitation erosion mechanisms and corrosion kinetics can establish and increase erosion rate. In the present study, the cavitation erosion-corrosion behaviour of ASTM A27 steel in natural river water is investigated. This paper state the approach which has been used to enlighten the synergy between both phenomena. For this, a 20 kHz vibratory test according ASTM G32 standard is coupled to an electrochemical cell to be able to follow the different corrosion parameters during the tests to get evidence of the damaging mechanism. Moreover, mass losses have been followed during the exposure time. The classical degradation parameters (cumulative weight loss and erosion rate) are determined. Furthermore, a particular effort has been implemented to determine the evolution of surface damages in terms of pitting, surface cracking, material removal and surface corrosion. For this, scanning electron microscopy has been used to link the microstructure to the material removal mechanisms

  20. Lower limb alignment characteristics are not associated with running injuries in runners: Prospective cohort study.

    Science.gov (United States)

    Hespanhol Junior, Luiz Carlos; de Carvalho, Aline Carla Araújo; Costa, Leonardo Oliveira Pena; Lopes, Alexandre Dias

    2016-11-01

    There is conflicting evidence on the association between lower limb alignment characteristics and the incidence of running-related injury (RRI). Therefore, the primary aim of this study was to investigate the association between lower limb alignment characteristics and the incidence proportion of RRI in a convenience sample of recreational runners. A total of 89 recreational runners were included in this prospective cohort study. These participants had been running for at least six months and were injury-free at baseline. Lower limb alignment measurements were conducted in order to calculate lower limb discrepancy, Q-angle, subtalar angle and plantar index. All participants also answered a baseline and biweekly online surveys about their running routine, history of RRI and newly developed RRI over a period of 12 weeks. The prevalence of previous RRI and the 12-week incidence proportion of new RRI were calculated. Logistic regression analysis was performed to estimate the association between lower limb length discrepancy, Q-angle, subtalar angle and plantar ach index with the incidence proportion of RRI. The prevalence of previous RRI was 55.1% (n = 49). The 12-week incidence proportion of new RRI was 27.0% (n = 24). Muscle injuries and tendinopathies were the main types of RRI identified. The lower leg and the knee were the main anatomical regions affected. We did not find significant associations between lower limb length discrepancy, Q-angle, subtalar angle and plantar arch index and injury occurrence.

  1. Long-term success and risk for marathon runners; Langzeiterfolg und Risiko der Marathonlaeufer

    Energy Technology Data Exchange (ETDEWEB)

    Schueller-Weidekamm, C. [Medizinische Universitaet Wien (Austria). AKH, Abteilung fuer Neuroradiologie und Muskuloskelettale Radiologie, Klinik fuer Radiodiagnostik

    2010-05-15

    The popularity of marathon running has increased during recent years, which is reflected by the dramatic increase in the number of competitions and participants. Running a marathon itself does not usually cause any severe lesions of the joints but the problems mostly occur during training prior to the marathon. Before the event runners often question whether they can successfully take part in the competition and cope with the pain that might occur during running. In addition to the rare acute trauma, which is in general caused by falls or slipping, chronic injuries are of particular relevance for long distance running. This article describes the typical patterns of injuries to long distance runners, the positive effects of running a marathon and the risk factors for injuries. (orig.) [German] Die Popularitaet des Marathonlaufens ist in den letzten Jahren gestiegen, was an der rasch zunehmenden Anzahl von Wettbewerben und Teilnehmern erkennbar ist. Nicht der Marathonlauf an sich ist belastend fuer die Gelenke, sondern meistens spielen sich die Probleme schon im Vorfeld waehrend der Trainingsvorbereitung ab. Eine der wichtigsten Fragen fuer jeden Laeufer vor dem grossen Ereignis ist, ob es trotz der haeufig auftretenden Gelenkschmerzen waehrend des Laufens moeglich ist, am Marathonlauf erfolgreich teilzunehmen. Neben den seltenen akuten Verletzungen, die durch Stuerze oder Fehltritte zu Stande kommen, stehen bei den Langstreckenlaeufern eher die chronischen Verletzungen im Vordergrund. Dieser Artikel beschreibt die typischen Verletzungsmuster bei Langstreckenlaeufern, die positiven Effekte des Marathonlaufens sowie die Risikofaktoren fuer eine erhoehte Verletzungsgefahr. (orig.)

  2. Plantar Pressures During Long Distance Running: An Investigation of 10 Marathon Runners

    Directory of Open Access Journals (Sweden)

    Erik Hohmann, Peter Reaburn, Kevin Tetsworth, Andreas Imhoff

    2016-06-01

    Full Text Available The objective of this study was to record plantar pressures using an in-shoe measuring system before, during, and after a marathon run in ten experienced long-distance runners with a mean age of 37.7 ± 11.5 years. Peak and mean plantar pressures were recorded before, after, and every three km during a marathon race. There were no significant changes over time in peak and mean plantar pressures for either the dominant or non-dominant foot. There were significant between foot peak and mean plantar pressure differences for the total foot (p = 0.0001, forefoot (p = 0.0001, midfoot (p = 0.02 resp. p = 0.006, hindfoot (p = 0.0001, first ray (p = 0.01 resp. p = 0.0001 and MTP (p = 0.05 resp. p = 0.0001. Long-distance runners do not demonstrate significant changes in mean or peak plantar foot pressures over the distance of a marathon race. However, athletes consistently favoured their dominant extremity, applying significantly higher plantar pressures through their dominant foot over the entire marathon distance.

  3. Prevalence of injuries in amateur street runners precuring up to 10 km

    Directory of Open Access Journals (Sweden)

    Elizeth Garcia de Araújo Oliveira

    2018-01-01

    Full Text Available Compared to most exercise and sports activities, street racing is highly versatile as it can be performed in a wide variety of indoor or outdoor environments, on lane or uneven terrain. Physical exercise is usually associated with the well-being of its practitioners. Many people who seek healthier lifestyle habits, such as controlling body weight and improving physical fitness, end up choosing the race as a modality. Among its various manifestations, the race is one of the modalities with many fans, both for ease in its practice, as well as for the health benefits and the low cost. To verify the prevalence of injuries in amateur street runners that cover up to 10 km. A quantitative research was carried out through a semi-structured questionnaire with open questions. Included in this study were amateur athletes who had been racing for at least three months, at least twice a week, and were 18 years of age or older. A total of 70 questionnaires were sent, of which 30 were viable. Eight participants are women and 22 are men. Most respondents do not do pre-employment pre-race work. Among men, 14 had some type of injury or sensation of pain. Among women only 4. Amateur street runners that cover up to 10 km have mostly knee injuries, being present in women the calf, thigh and ankle injuries.

  4. Traffic speed management

    Directory of Open Access Journals (Sweden)

    Subotić Jovana Lj.

    2014-01-01

    Full Text Available Speed, and vehicles themselves, affect the level of service and road safety, quality of life, noise from traffic, the environment, health, air pollution, emission of carbon dioxide, global warming, the economy and consumption of non-renewable energy such as oil. Therefore, the speed management of the traffic of multiple significance and that should be primarily to provide effective and economical conditions of the modern and preventive protection of human life as the greatest treasure and then the material resources. The way to accomplish this is by using various (different measures such as: appropriate planning and projecting roads and streets, speed control, the legislation, enforcement, campaigns, education, advanced technologies (ITS.

  5. Do running speed and shoe cushioning influence impact loading and tibial shock in basketball players?

    Directory of Open Access Journals (Sweden)

    Wing-Kai Lam

    2018-05-01

    Full Text Available Background Tibial stress fracture (TSF is a common injury in basketball players. This condition has been associated with high tibial shock and impact loading, which can be affected by running speed, footwear condition, and footstrike pattern. However, these relationships were established in runners but not in basketball players, with very little research done on impact loading and speed. Hence, this study compared tibial shock, impact loading, and foot strike pattern in basketball players running at different speeds with different shoe cushioning properties/performances. Methods Eighteen male collegiate basketball players performed straight running trials with different shoe cushioning (regular-, better-, and best-cushioning and running speed conditions (3.0 m/s vs. 6.0 m/s on a flat instrumented runway. Tri-axial accelerometer, force plate and motion capture system were used to determine tibial accelerations, vertical ground reaction forces and footstrike patterns in each condition, respectively. Comfort perception was indicated on a 150 mm Visual Analogue Scale. A 2 (speed × 3 (footwear repeated measures ANOVA was used to examine the main effects of shoe cushioning and running speeds. Results Greater tibial shock (P 0.14; η2 = 0.13. Discussion There may be an optimal band of shoe cushioning for better protection against TSF. These findings may provide insights to formulate rehabilitation protocols for basketball players who are recovering from TSF.

  6. Speed of light exceeded in 31st CERN Relay

    CERN Multimedia

    2001-01-01

    In the closest-ever finish of the CERN relay race, Florian Marinet (number 54) of the Neutrinos to Gran Sasso team just fails to catch Pierre Maesen of The Shabbys on the line. The AThLetic AceS team (number 76) won the Veterans category by just 3 seconds from long-time participants The Lynx Runners, who didn't leave empty handed. They picked up the cup that is drawn at random. Evidence for new physics? No, simply evidence for faster legs. Only at CERN could the speed of light come third to a team called The Shabbys. But that's exactly what happened on Wednesday 23 May when the team from PS Division lifted the Opitz cup after winning the 31st CERN relay race. The Shabbys sped home in 10 minutes 53 seconds, just 0.3 of a second ahead of the 'Neutrinos to Gran Sasso' team. There's some logic there since it is the PS complex that will provide the protons that will give rise to the neutrino beam. As for 'c0 the speed of light', they took a relatively leisurely 11 minutes 1.6 seconds to cover the course. A total...

  7. High-Speed Photography

    International Nuclear Information System (INIS)

    Paisley, D.L.; Schelev, M.Y.

    1998-01-01

    The applications of high-speed photography to a diverse set of subjects including inertial confinement fusion, laser surgical procedures, communications, automotive airbags, lightning etc. are briefly discussed. (AIP) copyright 1998 Society of Photo-Optical Instrumentation Engineers

  8. Wind_Speeds_Master

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set included wind speeds for each subregion in the study (Georges Bank, Gulf of Maine, Southern New England, Middle Atlantic Bight) . The data came from...

  9. High speed data acquisition

    International Nuclear Information System (INIS)

    Cooper, P.S.

    1997-07-01

    A general introduction to high speed data acquisition system techniques in modern particle physics experiments is given. Examples are drawn from the SELEX(E78 1) high statistics charmed baryon production and decay experiment now taking data at Fermilab

  10. Normal results of post-race thallium-201 myocardial perfusion imaging in marathon runners with elevated serum MB creatine kinase levels

    International Nuclear Information System (INIS)

    Siegel, A.J.; Silverman, L.M.; Holman, B.L.

    1985-01-01

    Elevated cardiac enzyme values in asymptomatic marathon runners after competition can arise from skeletal muscle through exertional rhabdomyolysis, silent injury to the myocardium, or a combined tissue source. Peak post-race levels of the MB isoenzyme of creatine kinase are similar to values in patients with acute myocardial infarction. Previously reported normal results of infarct-avid myocardial scintigraphy with technetium 99m pyrophosphate in runners after competition suggest a non-cardiac source but cannot exclude silent injury to the myocardium. Therefore, thallium 201 myocardial perfusion imaging was performed in runners immediately after competition together with determination of sequential cardiac enzyme levels. Among 15 runners tested, the average peak in serum MB creatine kinase 24 hours after the race was 128 IU/liter with a cumulative MB creatine kinase release of 117 IU/liter; these values are comparable to those in patients with acute transmural myocardial infarction. Thallium 201 myocardial scintigraphic results were normal in five runners randomly selected from those who volunteered for determination of sequential blood levels. It is concluded that elevations of serum MB creatine kinase in marathon runners arise from a skeletal muscle source and that thallium 201 myocardial scintigraphy is useful to assess runners for myocardial injury when clinical questions arise

  11. High speed heterostructure devices

    CERN Document Server

    Beer, Albert C; Willardson, R K; Kiehl, Richard A; Sollner, T C L Gerhard

    1994-01-01

    Volume 41 includes an in-depth review of the most important, high-speed switches made with heterojunction technology. This volume is aimed at the graduate student or working researcher who needs a broad overview andan introduction to current literature. Key Features * The first complete review of InP-based HFETs and complementary HFETs, which promise very low power and high speed * Offers a complete, three-chapter review of resonant tunneling * Provides an emphasis on circuits as well as devices.

  12. The experience of breast pain (mastalgia) in female runners of the 2012 London Marathon and its effect on exercise behaviour.

    Science.gov (United States)

    Brown, Nicola; White, Jennifer; Brasher, Amanda; Scurr, Joanna

    2014-02-01

    For female marathon runners, breast pain (mastalgia) may be an important issue which has yet to be considered. This study aimed to determine the prevalence and severity of mastalgia in female marathon runners, identify factors that increase mastalgia and methods used to overcome mastalgia, and explore the impact that mastalgia may have on marathon training. 1397 female marathon runners were surveyed at the 2012 London Marathon Registration. All participants who completed the four-part, 30-question survey in its entirety have been included in the analysis (n=1285). 32% of participants experienced mastalgia. This was significantly related to cup size and was greater during vigorous compared with moderate physical activity. Exercise-related factors were the primary factors reported to increase mastalgia participation. Seventeen per cent of symptomatic participants reported that mastalgia affected their exercise behaviour. Methods reportedly used to overcome mastalgia included pain medication and firm breast support; however, 44% of participants took no measures to relieve symptoms despite over half describing their mastalgia as discomforting. Mastalgia was experienced by a third of marathon runners and was found to be related to breast size which has previously been unreported. The link between exercise and mastalgia has yet to be established; however, this study identified that exercise was the most prevalent factor in mastalgia occurrence which may have implications for its management. The number of participants who took no measures to relieve their mastalgia, or resorted to pain medication, highlights the importance and significance of research into exercise-related mastalgia.

  13. Analysis of Hassan's Tragedy in "The Kite Runner" from the Three-Dimensional Ethical Perspective

    Science.gov (United States)

    Yuan-yuan, Peng

    2018-01-01

    Hassan in "The Kite Runner" was brave, kind-hearted and loyal, but he still ended up with misery. From the three dimensional ethical perspective, Hassan's tragedy is not only greatly related to national and religious ethics, but also influenced by deformed family ethics. Thus it can be seen that national discrimination and religious…

  14. Mental skills comparison between elite sprint and endurance track and field runners according to their genetic polymorphism: a pilot study.

    Science.gov (United States)

    Znazen, Hela; Slimani, Maamer; Miarka, Bianca; Butovskaya, Marina; Siala, Hajer; Messaoud, Taieb; Chamari, Karim; Souissi, Nizar

    2017-09-01

    Achieving excellence in track and field athletes requires specific mental skills. The aim of the present study was to compare the mental skills between elite sprint and endurance athletes. Forty elite athletes (age 20.55±2.22 years, body mass 74.8±7.9 kg, height 1.70±0.1 m) participated in the present study. The athletes were classified into two groups according to their genetic polymorphism to physical activity: Endurance group (allele I, N.=20) and power group (allele D, N.=20). The mental skills were assessed by means of Ottawa Mental Skill Assessment Tool-3 inventory (OMSAT-3: based in foundation mental skills, psychosomatic skills, and cognitive skills subscales) before the competition period. Furthermore, genetic data were also collected. Sprint and endurance runners were participating in Tunisian National championship. The results showed a significant difference between elite sprint and endurance runners in the foundation mental and psychosomatic skills subscales (all, Pstudy revealed that goal setting, commitment, stress reactions, fear control, imagery, competition planning and mental practice were significantly higher among the elite sprint runners compared to the endurance runners (all, Pstudy could confirm the widely acclaimed research assumption that mental skills, such as goal setting, commitment and mental practice, are the predictor variables of power performances, while endurance performances are associated with different mental skills components. Finally, the results may inform applied practitioners regarding the differences in mental skill demands between power and endurance athletes and the genetic predisposition of practitioners.

  15. Design, Modeling, and CFD Analysis of a Micro Hydro Pelton Turbine Runner: For the Case of Selected Site in Ethiopia

    Directory of Open Access Journals (Sweden)

    Tilahun Nigussie

    2017-01-01

    Full Text Available This paper addresses the design, modeling, and performance analysis of a Pelton turbine using CFD for one of the selected micro hydro potential sites in Ethiopia to meet the requirements of the energy demands. The site has a net head of 47.5 m and flow rate of 0.14 m3/s. The design process starts with the design of initial dimensions for the runner based on different literatures and directed towards the modeling of bucket using CATIA V5. The performance of the runner has been analyzed in ANSYS CFX (CFD under given loading conditions of the turbine. Consequently, the present study has also the ambition to reduce the size of the runner to have a cost effective runner design. The case study described in this paper provides an example of how the size of turbine can affect the efficiency of the turbine. These were discussed in detail which helps in understanding of the underlying fluid dynamic design problem as an aid for improving the efficiency and lowering the manufacturing cost for future study. The result showed that the model is highly dependent on the size and this was verified and discussed properly using flow visualization of the computed flow field and published result.

  16. Exploring Adolescents' Multimodal Responses to "The Kite Runner": Understanding How Students Use Digital Media for Academic Purposes

    Science.gov (United States)

    Jocius, Robin

    2013-01-01

    This qualitative study explores how adolescent high school students in an AP English class used multiple forms of media (the internet, digital video, slide show software, video editing tools, literary texts, and writing) to respond to and analyze a contemporary novel, "The Kite Runner". Using a multimodal analysis framework, the author explores…

  17. From problem to solution : developing a personalized smartphone application for recreational runners following a three-step design approach

    NARCIS (Netherlands)

    Vos, S.B.; Janssen, M.A.; Goudsmit, J.; Lauwerijssen, C.; Brombacher, A.C.

    2016-01-01

    The aim of this paper is to design and test a smartphone application which supports personalized running experiences for less experienced runners. As a result of a multidisciplinary three-step design approach Inspirun was developed. Inspirun is a personalized running-application for Android

  18. The NLstart2run study : Training-related factors associated with running-related injuries in novice runners

    NARCIS (Netherlands)

    Kluitenberg, Bas; van der Worp, Henk; Huisstede, Bionka M A; Hartgens, Fred; Diercks, Ron; Verhagen, Evert; van Middelkoop, Marienke

    2016-01-01

    Objectives: The incidence of running-related injuries is high. Some risk factors for injury were identified in novice runners, however, not much is known about the effect of training factors on injury risk. Therefore, the purpose of this study was to examine the associations between training factors

  19. Prevalence, incidence and course of lower extremity injuries in runners during a 12-month follow-up period

    NARCIS (Netherlands)

    Poppel van, D.; Scholten-Peeters, G G M; van Middelkoop, M.; Verhagen, Arianne P

    2014-01-01

    To describe the incidence, 12-month prevalence, and course of lower extremity injuries that occurred during and after the Amgen Singelloop Breda in 2009. The design was based on a prospective cohort study with a population-based setting. In total, 3605 registered runners received a web-based

  20. The NLstart2run study: Incidence and risk factors of running-related injuries in novice runners.

    Science.gov (United States)

    Kluitenberg, B; van Middelkoop, M; Smits, D W; Verhagen, E; Hartgens, F; Diercks, R; van der Worp, H

    2015-10-01

    Running is a popular form of physical activity, despite of the high incidence of running-related injuries (RRIs). Because of methodological issues, the etiology of RRIs remains unclear. Therefore, the purposes of the study were to assess the incidence of RRIs and to identify risk factors for RRIs in a large group of novice runners. In total, 1696 runners of a 6-week supervised "Start to Run" program were included in the NLstart2run study. All participants were aged between 18 and 65, completed a baseline questionnaire that covered potential risk factors, and completed at least one running diary. RRIs were registered during the program with a weekly running log. An RRI was defined as a musculo-skeletal complaint of the lower extremity or back attributed to running and hampering running ability for three consecutive training sessions. During the running program, 10.9% of the runners sustained an RRI. The multivariable Cox regression analysis showed that a higher age, higher BMI, previous musculo-skeletal complaints not attributed to sports and no previous running experience were related to RRI. These findings indicate that many novice runners participating in a short-term running program suffer from RRIs. Therefore, the identified risk factors should be considered for screening and prevention purposes. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. Predictors of Running-Related Injuries in Novice Runners Enrolled in a Systematic Training Program A Prospective Cohort Study

    NARCIS (Netherlands)

    Buist, Ida; Bredeweg, Steef W.; Lemmink, Koen A. P. M.; van Mechelen, Willem; Diercks, Ron L.

    Background: The popularity of running is still growing. As participation increases, running-related injuries also increase. Until now, little is known about the predictors for injuries in novice runners. Hypothesis: Predictors for running-related injuries (RRIs) will differ between male and female

  2. The NLstart2run study: Training-related factors associated with running-related injuries in novice runners

    NARCIS (Netherlands)

    Kluitenberg, Bas; van der Worp, Henk; Huisstede, Bionka M. A.; Hartgens, Fred; Diercks, Ronald; Verhagen, Evert; van Middelkoop, Marienke

    Objectives: The incidence of running-related injuries is high. Some risk factors for injury were identified in novice runners, however, not much is known about the effect of training factors on injury risk. Therefore, the purpose of this study was to examine the associations between training factors

  3. BladeRunners and Picasso Cafe: A Case Study Evaluation of Two Work-Based Training Programs for Disadvantaged Youth.

    Science.gov (United States)

    Currie, Sheila; Foley, Kelly; Schwartz, Saul; Taylor-Lewis, Musu

    In 1998, Canada's Social Research and Demonstration Corporation (SRDC) conducted case studies of two work-based training and skill development programs for street youth in Vancouver, British Columbia. The BladeRunners program places youth on construction sites while encouraging them to work toward an apprenticeship in the building trades. The…

  4.  Running speed during training and percent body fat predict race time in recreational male marathoners

    Directory of Open Access Journals (Sweden)

    Barandun U

    2012-07-01

    Full Text Available  Background: Recent studies have shown that personal best marathon time is a strong predictor of race time in male ultramarathoners. We aimed to determine variables predictive of marathon race time in recreational male marathoners by using the same characteristics of anthropometry and training as used for ultramarathoners.Methods: Anthropometric and training characteristics of 126 recreational male marathoners were bivariately and multivariately related to marathon race times.Results: After multivariate regression, running speed of the training units (β=-0.52, P<0.0001 and percent body fat (β=0.27, P <0.0001 were the two variables most strongly correlated with marathon race times. Marathon race time for recreational male runners may be estimated to some extent by using the following equation (r2 = 0.44: race time (minutes = 326.3 + 2.394 × (percent body fat, % – 12.06 × (speed in training, km/hours. Running speed during training sessions correlated with prerace percent body fat (r=0.33, P=0.0002. The model including anthropometric and training variables explained 44% of the variance of marathon race times, whereas running speed during training sessions alone explained 40%. Thus, training speed was more predictive of marathon performance times than anthropometric characteristics.Conclusion: The present results suggest that low body fat and running speed during training close to race pace (about 11 km/hour are two key factors for a fast marathon race time in recreational male marathoner runners.Keywords: body fat, skinfold thickness, anthropometry, endurance, athlete

  5. The effect of three surface conditions, speed and running experience on vertical acceleration of the tibia during running.

    Science.gov (United States)

    Boey, Hannelore; Aeles, Jeroen; Schütte, Kurt; Vanwanseele, Benedicte

    2017-06-01

    Research has focused on parameters that are associated with injury risk, e.g. vertical acceleration. These parameters can be influenced by running on different surfaces or at different running speeds, but the relationship between them is not completely clear. Understanding the relationship may result in training guidelines to reduce the injury risk. In this study, thirty-five participants with three different levels of running experience were recruited. Participants ran on three different surfaces (concrete, synthetic running track, and woodchip trail) at two different running speeds: a self-selected comfortable speed and a fixed speed of 3.06 m/s. Vertical acceleration of the lower leg was measured with an accelerometer. The vertical acceleration was significantly lower during running on the woodchip trail in comparison with the synthetic running track and the concrete, and significantly lower during running at lower speed in comparison with during running at higher speed on all surfaces. No significant differences in vertical acceleration were found between the three groups of runners at fixed speed. Higher self-selected speed due to higher performance level also did not result in higher vertical acceleration. These results may show that running on a woodchip trail and slowing down could reduce the injury risk at the tibia.

  6. Everyone Deserves a Speeding Ticket.

    Science.gov (United States)

    Burris, Harold

    1993-01-01

    Presents a first day physics activity having students determine the fine for a speeding ticket if the speeds considered include the earth's rotation and revolution speed, and the movement through the galaxy. (MDH)

  7. Unchanged Erythrocyte Profile After Exposure to Cryogenic Temperatures in Elder Marathon Runners

    Directory of Open Access Journals (Sweden)

    Jadwiga Szymura

    2018-05-01

    Full Text Available Objective: Endurance runners may experience “sports anemia” resulting from intravascular hemolysis. In addition, aging has negative impact on hematopoiesis and rheological properties of blood, and erythrocyte membranes in older people are more vulnerable to oxidative damage, which together can lead to anemia. Whole-body cryostimulation (WBCST is increasingly used in the elderly as a method of biological regeneration of athletes or therapy and preventive treatment. That is why the aim of the study was to determine whether repeated WBCST had an effect on the erythrocyte system in master marathon runners, compared to non-training men.Methods: Ten marathon runners (men aged 55.9 ± 5.5 years, training experience 6.71 ± 5.79 years and 10 non-training (men aged 62.0 ± 5.8 years were subjected to a series of 24 WBCST (3 min, -130°C performed every other day. Erythrocyte levels, interleukin-3 (IL-3, erythropoietin (EPO, haptoglobin, bilirubin, and extracellular hemoglobin (HGBecf concentrations were determined in the blood before and after 12, 24 WBCST, as well as 7 days after their completion.Results: The concentrations of EPO and IL-3 were significantly increased 7 days after the completion of WBCST in both groups (P < 0.05. The erythrocyte content and indicators, the bilirubin, haptoglobin, and HGBecf levels in each group did not change as a result of WBCST. In order to document hemolytic changes and/or factors affecting the severity of erythropoiesis, correlations between growth erythropoietic factors, erythrocyte and hemolytic factors as well as mutual correlations between hemolytic indexes were calculated. There was a positive correlation (P < 0.05 between the EPO and IL-3, bilirubin, mean corpuscular hemoglobin, and red blood cell distribution width – standard deviation. There was also a positive correlation between the concentrations of bilirubin and HGBecf, and a negative correlation between haptoglobin and HGBecf as well as bilirubin

  8. Seasonal Strength Performance and Its Relationship with Training Load on Elite Runners

    Directory of Open Access Journals (Sweden)

    Carlos Balsalobre-Fernández

    2015-01-01

    Full Text Available The aim of this study was to analyze the time-course of force production of elite middle and long-distance runners throughout an entire season and at the end of the off-season, as well as its relationships with training load and hormonal responses. Training load was recorded daily throughout an entire season by measuring and evaluating the session distance (km, training zone and session-RPE in a group of 15 elite middle and long-distance runners (12 men, 3 women; age = 26.3 ± 5.1yrs, BMI = 19.7 ± 1.1. Also, basal salivary-free cortisol levels were measured weekly, and 50-metre sprints, mean propulsive velocity (MPV, mean propulsive power (MPP, repetition maximum (RM and peak rate of force development (RFD of half-squats were measured 4 times during the season, and once more after the off-season break. There were no significant variations in force production during the season or after the off-season break, except for the RFD (-30.2%, p = 0.005 values, which changed significantly from the beginning to the end of the season. Significant correlations were found between session-RPE and MPV (r = -0.650, p = 0.004, MPP (r = -0.602, p = 0.009, RM (r = -0.650, p = 0.004, and the 50-metre sprint (r = 0.560, p = 0.015. Meanwhile, salivary-free cortisol correlated significantly with the 50-metre sprint (r = 0.737, p < 0.001 and the RM ( r = -0.514, p = 0.025. Finally, the training zone correlated with the 50-metre sprint (r = -0.463, p = 0.041. Session-RPE, training zone and salivary-free cortisol levels are related to force production in elite middle and long-distance runners. Monitoring these variables could be a useful tool in controlling the training programs of elite athletes.

  9. The Perceived Naturalness of Virtual Walking Speeds during WIP Locomotion

    DEFF Research Database (Denmark)

    Nilsson, Niels Chr.; Serafin, Stefania; Nordahl, Rolf

    2016-01-01

    It is well established that individuals tend to underestimate visually presented walking speeds when relying on treadmills for virtual walking. However, prior to the present studies this perceptual distortion had not been observed in relation to Walking-in-Place (WIP) locomotion, and a number...... to how gait cycle characteristics, visual display properties, and methodological differences affect speed underestimation during treadmill and WIP locomotion. The studies suggested the following: A significant main effect was found for step frequency; both display and geometric field of view were...... inversely proportional to the degree of underestimation; varying degrees of peripheral occlusion and increased HMD weight did not yield significant main effects; and the choice of method (i.e., how the speeds were presented) had a significant effect on the upper and lower bounds of what speeds were...

  10. Peripheral nerve conduits: technology update

    Science.gov (United States)

    Arslantunali, D; Dursun, T; Yucel, D; Hasirci, N; Hasirci, V

    2014-01-01

    Peripheral nerve injury is a worldwide clinical problem which could lead to loss of neuronal communication along sensory and motor nerves between the central nervous system (CNS) and the peripheral organs and impairs the quality of life of a patient. The primary requirement for the treatment of complete lesions is a tension-free, end-to-end repair. When end-to-end repair is not possible, peripheral nerve grafts or nerve conduits are used. The limited availability of autografts, and drawbacks of the allografts and xenografts like immunological reactions, forced the researchers to investigate and develop alternative approaches, mainly nerve conduits. In this review, recent information on the various types of conduit materials (made of biological and synthetic polymers) and designs (tubular, fibrous, and matrix type) are being presented. PMID:25489251

  11. Peripheral Atherectomy: Applications and Techniques.

    Science.gov (United States)

    Mittleider, Derek; Russell, Erich

    2016-06-01

    Peripheral atherectomy is a class of procedures that is rapidly increasing in volume. Multiple classes of devices exist, and newer variants are added to the market annually. The devices see wide application for de novo lesions, in-stent restenosis, and adjunctive therapy for drug-coated balloons. The body of evidence supporting atherectomy is less robust than for many other peripheral therapies. The frequency and severity of complications from atherectomy can be significant compared with angioplasty and stenting, and familiarity with preventative and bailout techniques is essential for the interventionalist. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. [Atherectomy for peripheral arterial disease].

    Science.gov (United States)

    Londero, Louise Skovgaard; Høgh, Annette Langager; Lindholt, Jes Sanddal

    2015-04-13

    Symptomatic peripheral arterial disease is managed according to national and international guidelines and the number of vascular reconstructions performed each year has increased over the past decade mainly due to an increasing frequency of endovascular procedures. Atherectomy as an alternative to the established treatment of symptomatic peripheral arterial disease has recently been analysed in a Cochrane review. In Denmark, atherectomy is not performed and so far the evidence is poor as the method is not an alternative to the established treatment in this country.

  13. Imaging of the peripheral retina

    Directory of Open Access Journals (Sweden)

    Marcus Kernt

    2013-01-01

    Full Text Available The technical progress of the recent years has revolutionized imaging in ophthalmology. Scanning laser ophthalmoscopy (SLO, digital angiography, optical coherence tomography (OCT, and detection of fundus autofluorescence (FAF have fundamentally changed our understanding of numerous retinal and choroidal diseases. Besides the tremendous advances in macular diagnostics, there is more and more evidence that central pathologies are often directly linked to changes in the peripheral retina. This review provides a brief overview on current posterior segment imaging techniques with a special focus on the peripheral retina.

  14. PERSONALITY AND SPEEDING

    Directory of Open Access Journals (Sweden)

    Richard TAY

    2003-01-01

    Full Text Available While there has been extensive research on the effect of sensation seeking on risky driving, relatively little research has been conducted on Type-A personality. The motivations for speeding are likely to be different for each group and these differences have important implications for the design, implementation and expected efficacy of road safety countermeasures. This paper examines the influence of sensation seeking and Type-A behavior pattern on speeding behaviour. A sample of 139 staff and students in an Australian university were surveyed in July 2001 to gather information on their gender, age, personality and self-reported speeding behaviour. The data were analysed using correlations and analysis of variance procedures. Finally, some implications for road safety are discussed.

  15. Design of a high speed rotating mechanical shutter

    International Nuclear Information System (INIS)

    Stowers, I.F.; Merritt, B.T.; McFann, C.B.

    1979-01-01

    A high-speed rotating shutter was designed to operate in a 10 -6 Torr vacuum at the optical focus of a laser spatial filter. The shutter is basically a wheel, with a single 3 x 10-mm slot at the perimeter, which rotates with a peripheral speed of 1 km/s. The motor to drive the rotating wheel is magnetically suspended and synchronously wound. The wheel achieves a 4 μs opening time and a timing accuracy of better than 0.2 μs

  16. Investigation of Blade Angle of an Open Cross-Flow Runner

    Science.gov (United States)

    Katayama, Yusuke; Iio, Shouichiro; Veerapun, Salisa; Uchiyama, Tomomi

    2015-04-01

    The aim of this study was to develop a nano-hydraulic turbine utilizing drop structure in irrigation channels or industrial waterways. This study was focused on an open-type cross-flow turbine without any attached equipment for cost reduction and easy maintenance. In this study, the authors used an artificial indoor waterfall as lab model. Test runner which is a simple structure of 20 circular arc-shaped blades sandwiched by two circular plates was used The optimum inlet blade angle and the relationship between the power performance and the flow rate approaching theoretically and experimentally were investigated. As a result, the optimum inlet blade angle due to the flow rate was changed. Additionally, allocation rate of power output in 1st stage and 2nd stage is changed by the blade inlet angle.

  17. Examination of “Pre-competition” anxiety levels, of mid-distance runners: A quantitative approach

    Directory of Open Access Journals (Sweden)

    Bebetsos Evangelos

    2015-09-01

    Full Text Available Mid-distance runners are subject to intense cognitive and somatic anxiety, not only during competition but also during practice. An important variable which may influence athletes’ performance is perceived behavioral control on anxiety. The aim of the present study was to examine whether aspects such as sex, sport/competition experience and weekly practices, differentiated the participants respectively. The participants consisted of 110 athletes, 61 male and 49 female athletes, between the ages of 15 and 28 (Μ=20.05, SD=2.82.They all completed the Greek version of the “Pre- Race Questionnaire”. Results indicated differences between the less experienced and more experienced athletes in almost all factors of the questionnaire, for both sport/competition experience, and weekly practices. No gender differences were shown. Overall, results could help sport professionals such as coaches and the athletes themselves, become more familiar with the sport-specific psychological aspects involved in their unique sport.

  18. Atypical femoral neck stress fracture in a marathon runner: a case report and literature review.

    LENUS (Irish Health Repository)

    2012-02-01

    BACKGROUND: Femoral neck stress fractures are relatively rare and may present as sports-related injuries. The presentation is variable, and prompt diagnosis facilitates the earliest return to pre-morbid functional activity levels. Delayed detection may precipitate femoral non-union or avascular necrosis, resulting in long-term functional deficit. AIMS: We present the case of a basicervical femoral neck stress fracture occurring in a 23-year-old marathon runner. The pathophysiology and practical management issues related to this unusual injury pattern are discussed. CONCLUSION: The growing interest in amateur athletic activities should raise the index of suspicion for stress fractures of the femoral neck in healthy adults with atypical hip pain. Increased levels of patient education and physician awareness can reduce the incidence of long-term morbidity in cases of this unusual sports-related injury.

  19. Latinoamérica y el Apocalipsis: íconos visuales en Blade Runner y Elysium

    Directory of Open Access Journals (Sweden)

    Nelson Arteaga Botello

    2015-07-01

    Full Text Available En el presente trabajo se subraya cómo las distopías fílmicas proyectan formas específicas de dominación y tensiones sociales que es posible encontrar en las sociedades contemporáneas. Se analizan las películas Blade Runner y Elysium a partir de cuatro elementos iconográficos que comparten: la ciudad de Los Ángeles, el abandono de la tierra por sus élites, un contexto social multicultural, así como la presencia de tecnologías de vigilancia social. El trabajo muestra cómo estas películas construyen una idea de lo latinoamericano que da sentido a los escenarios apocalípticos futuros, y proyectan a la vez el presente de las sociedades latinoamericanas.

  20. Concurrent fatigue and postactivation potentiation during extended interval training in long-distance runners

    Directory of Open Access Journals (Sweden)

    Pedro Ángel Latorre-Román

    2014-12-01

    Full Text Available The purpose of this study is to analyze acute effect of running extended interval training(EIT on vertical jump (VJ and handgrip strength (HS performance in experienced endurance athletes. In order to analyze mechanical parameters of the VJ and HS between runs, sixteen experienced male athletes performed an EIT (4x3x400m. The results show that fatigue induced by EIT does not impair handgrip strength or VJ performance. A significant improvement (p< .05 was noted for VJ due to the postactivation potentiation (PAP phenomenon. A positive correlation (r= .619, p= .011 was found between VJ and lactate. The results suggest that experienced long-distance runners can maintain their strength levels and, consequently, work capacity, despite the induced fatigue by the field training demand. Therefore, VJ performance during EIT can be used as an indicator of muscular adaptations to training and, together, with handgrip strength, become indicators of fatigue. These indicators allow proper prescription training routines.