Physiological and training characteristics of recreational marathon runners

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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

Four Weeks of Classical Altitude Training Increases Resting Metabolic Rate in Highly Trained Middle-Distance Runners.

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Woods, Amy L; Sharma, Avish P; Garvican-Lewis, Laura A; Saunders, Philo U; Rice, Anthony J; Thompson, Kevin G

2017-02-01

High altitude exposure can increase resting metabolic rate (RMR) and induce weight loss in obese populations, but there is a lack of research regarding RMR in athletes at moderate elevations common to endurance training camps. The present study aimed to determine whether 4 weeks of classical altitude training affects RMR in middle-distance runners. Ten highly trained athletes were recruited for 4 weeks of endurance training undertaking identical programs at either 2200m in Flagstaff, Arizona (ALT, n = 5) or 600m in Canberra, Australia (CON, n = 5). RMR, anthropometry, energy intake, and hemoglobin mass (Hb mass ) were assessed pre- and posttraining. Weekly run distance during the training block was: ALT 96.8 ± 18.3km; CON 103.1 ± 5.6km. A significant interaction for Time*Group was observed for absolute (kJ.day -1 ) (F-statistic, p-value: F (1,8) =13.890, p = .01) and relative RMR (F (1,8) =653.453, p = .003) POST-training. No significant changes in anthropometry were observed in either group. Energy intake was unchanged (mean ± SD of difference, ALT: 195 ± 3921kJ, p = .25; CON: 836 ± 7535kJ, p = .75). A significant main effect for time was demonstrated for total Hb mass (g) (F (1,8) =13.380, p = .01), but no significant interactions were observed for either variable [Total Hb mass (g): F (1,8) =1.706, p = .23; Relative Hb mass (g.kg -1 ): F (1,8) =0.609, p = .46]. These novel findings have important practical application to endurance athletes routinely training at moderate altitude, and those seeking to optimize energy management without compromising training adaptation. Altitude exposure may increase RMR and enhance training adaptation,. During training camps at moderate altitude, an increased energy intake is likely required to support an increased RMR and provide sufficient energy for training and performance.

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

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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.

Oxygen consumption of elite distance runners on an anti-gravity treadmill®.

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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.

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

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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.

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

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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.

Eating disorders and health in elite women distance runners.

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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.

Incidence and determinants of lower extremity running injuries in long distance runners: a systematic review

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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

Effects of Ramadan intermittent fasting on middle-distance running performance in well-trained runners.

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Brisswalter, Jeanick; Bouhlel, Ezzedine; Falola, Jean Marie; Abbiss, Christopher R; Vallier, Jean Marc; Hausswirth, Christophe; Hauswirth, Christophe

2011-09-01

To assess whether Ramadan intermittent fasting (RIF) affects 5000-m running performance and physiological parameters classically associated with middle-distance performance. Two experimental groups (Ramadan fasting, n = 9, vs control, n = 9) participated in 2 experimental sessions, one before RIF and the other at the last week of fasting. For each session, subjects completed 4 tests in the same order: a maximal running test, a maximal voluntary contraction (MVC) of knee extensor, 2 rectangular submaximal exercises on treadmill for 6 minutes at an intensity corresponding to the first ventilatory threshold (VT1), and a running performance test (5000 m). Eighteen, well-trained, middle-distance runners. Maximal oxygen consumption, MVC, running performance, running efficiency, submaximal VO(2) kinetics parameters (VO(2), VO(2)b, time constant τ, and amplitude A1) and anthropometric parameters were recorded or calculated. At the end of Ramadan fasting, a decrease in MVC was observed (-3.2%; P < 0.00001; η, 0.80), associated with an increase in the time constant of oxygen kinetics (+51%; P < 0.00007; η, 0.72) and a decrease in performance (-5%; P < 0.0007; η, 0.51). No effect was observed on running efficiency or maximal aerobic power. These results suggest that Ramadan changes in muscular performance and oxygen kinetics could affect performance during middle-distance events and need to be considered to choose training protocols during RIF.

Optimization of special physical fitness of sportswomen - super long distances runners by means of run training

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S.I. Karaulova

2016-06-01

Full Text Available Purpose: improvement of special physical fitness of sportswomen – super long distances runners by means of run training. Material: in the research 6 elite sportswomen of 25-27 years’ age participated. We analyzed documents of training proves planning; analyzed sportswomen’s diaries. Results: three cycle system of annual macro cycle’s construction was put in the base of modern training system for elite marathon sportswomen. We found general and partial volumes of run load of different orientation in annual macro cycle. Optimal duration of maximal load’s segments during anaerobic training was from 30 sec. to 3 minutes. Rest between segments was slow run during 3 – 8 minutes. With it, sportswomen fulfilled repeated run at segments of 15х200 m, 15х400 m, 12х600 m. Conclusions: effectiveness of system of sportswomen’s special physical fitness improvement is determined by rational correlation of differently oriented run means, which were directed at increase of special fitness level in marathon.

Tapering strategies in elite British endurance runners.

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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.

Cardiovascular Risks in Long Distance Runners.

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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.

Seasonal Strength Performance and Its Relationship with Training Load on Elite Runners

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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.

Narratives of Psychosocial Response to Microtrauma Injury among Long-Distance Runners

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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.

Cardiovascular responses to static exercise in distance runners and weight lifters

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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.

Altered neuroendocrine regulation of gonadotropin secretion in women distance runners.

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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

Pre- and postmarathon training habits of nonelite runners

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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

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

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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 ...

Oxygen Consumption of Elite Distance Runners on an Anti-Gravity Treadmill®

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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.

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

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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.

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

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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.

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

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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

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

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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.

Does the sex difference in competitiveness decrease in selective sub-populations? A test with intercollegiate distance runners.

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Deaner, Robert O; Lowen, Aaron; Rogers, William; Saksa, Eric

2015-01-01

Sex differences in some preferences and motivations are well established, but it is unclear whether they persist in selective sub-populations, such as expert financial decision makers, top scientists, or elite athletes. We addressed this issue by studying competitiveness in 1,147 varsity intercollegiate distance runners. As expected, across all runners, men reported greater competitiveness with two previously validated instruments, greater competitiveness on a new elite competitiveness scale, and greater training volume, a known correlate of competitiveness. Among faster runners, the sex difference decreased for one measure of competitiveness but did not decrease for the two other competitiveness measures or either measure of training volume. Across NCAA athletic divisions (DI, DII, DIII), the sex difference did not decrease for any competitiveness or training measure. Further analyses showed that these sex differences could not be attributed to women suffering more injuries or facing greater childcare responsibilities. However, women did report greater commitment than men to their academic studies, suggesting a sex difference in priorities. Therefore, policies aiming to provide men and women with equal opportunities to flourish should acknowledge that sex differences in some kinds of preferences and motivation may persist even in selective sub-populations.

Gonadotropin Pulsatllity in FemaIe Long Distance Runners

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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

Effect of Maximal Versus Supra-Maximal Exhausting Race on Lipid Peroxidation, Antioxidant Activity and Muscle-Damage Biomarkers in Long-Distance and Middle-Distance Runners.

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Mohamed, Said; Lamya, Ncir; Hamda, Mansour

2016-03-01

Exhausting physical exercise increases lipid peroxidation and causes important muscle damages. The human body tries to mitigate these adverse effects by mobilizing its antioxidant defenses. This study aims to investigate the effect of a maximal versus supra-maximal race sustained until exhaustion on lipid peroxidation, antioxidant activity and muscle-damage biomarkers in trained (i.e. long-distance and middle-distance runners) and sedentary subjects. The study has been carried out on 8 middle-distance runners (MDR), 9 long-distance runners (LDR), and 8 sedentary subjects (SS). Each subject has undergone two exhaustive running tests, the first one is an incremental event (VAMEVAL test), the second one is a constant supra-maximal intensity test (limited-time test). Blood samples were collected at rest and immediately after each test. A significant increase in malondialdehyde (MDA) concentrations was observed in SS and MDR after the VAMEVAL test and in LDR after the Limited-Time test. A significant difference was also observed between LDR and the other two groups after the VAMEVAL test, and between LDR and MDR after the Limited-Time test. Significant modifications, notably, in myoglobin, CK, LDH, IL-6, TNF-α, and TAS were likewise noted but depending on the race-type and the sportive specialty. Maximal and supra-maximal races induce a significant increase in lipid peroxidation and cause non-negligible inflammation and muscle damage. These effects were relatively related to the physical exercise type and the sportive specialty.

Preparticipation evaluation of novice, middle-age, long-distance runners.

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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.

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

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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.

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

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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.

Glucose uptake patterns in exercised skeletal muscles of elite male long-distance and short-distance runners.

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Tai, Suh-Jun; Liu, Ren-Shyan; Kuo, Ya-Chen; Hsu, Chi-Yang; Chen, Chi-Hsien

2010-04-30

The aim of this study was to determine glucose uptake patterns in exercised skeletal muscles of elite male long-distance and short-distance runners. Positron emission tomography (PET) using 18F-fluoro-2-deoxyglucose (FDG) was performed to determine the patterns of glucose uptake in lower limbs of short-distance (SD group, n=8) and long-distance (LD group, n=8) male runners after a modified 20 min Bruce treadmill test. Magnetic resonance imaging (MRI) was used to delineate the muscle groups in lower limbs. Muscle groups from hip, knee, and ankle movers were measured. The total FDG uptake and the standard uptake value (SUV) for each muscle group were compared between the 2 groups. For the SD and LD runners, the 2 major muscle groups utilizing glucose during running were knee extensors and ankle plantarflexors, which accounted for 49.3 +/- 8.1% (25.1 +/- 4.7% and 24.2 +/- 6.0%) of overall lower extremity glucose uptake for SD group, and 51.3 +/- 8.0% (27.2 +/- 2.7% and 24.0 +/- 8.1%) for LD group. No difference in muscle glucose uptake was noted for other muscle groups. For SD runners, the SUVs for the muscle groups varied from 0.49 +/- 0.27 for the ankle plantarflexors, to 0.20 +/- 0.08 for the hip flexor. For the LD runners, the highest and lowest SUVs were 0.43 +/- 0.15 for the ankle dorsiflexors and 0.21 +/- 0.19 for the hip. For SD and LD groups, no difference in muscle SUV was noted for the muscle groups. However, the SUV ratio between the ankle dorsiflexors and plantarflexors in the LD group was significantly greater than that in the SD group. We thus conclude that the major propelling muscle groups account for approximately 50% of lower limb glucose utilization during running. Thus, the other muscle groups involving maintenance of balance, limb deceleration, and shock absorption utilize an equal amount. This result provides a new insight into glucose distribution in skeletal muscle, suggesting that propellers and supporters are both energetically important

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

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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...

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

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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.

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

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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

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

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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.

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

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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.

Impact of Short-Term Training Camp on Aortic Blood Pressure in Collegiate Endurance Runners

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Tsubasa Tomoto

2018-03-01

Full Text Available To investigate the influence of short-term vigorous endurance training on aortic blood pressure (BP, pulse wave analysis was performed in 36 highly trained elite collegiate endurance runners before and after a 7-day intense training camp. Subjects participated three training sessions per day, which mainly consisted of long distance running and sprint training to reach the daily target distance of 26 km. After the camp, they were divided into two groups based on whether the target training was achieved. Aortic systolic BP, pulse pressure, and tension-time index (TTI, a surrogate index of the myocardial oxygen demand were significantly elevated after the camp in the accomplished group but not in the unaccomplished group, whereas the brachial BP remained unchanged in both groups. The average daily training distance was significantly correlated with the changes in aortic systolic BP (r = 0.608, p = 0.0002, pulse pressure (r = 0.415, p = 0.016, and TTI (r = 0.438, p = 0.011. These results suggest that aortic BP is affected by a short-term vigorous training camp even in highly trained elite endurance athletes presumably due to a greater training volume compared to usual.

Biochemical adaptations in middle-distance runners: an assessment of blood and anthropometric parameters

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Danila Di Majo

2014-12-01

Full Text Available In order to understand the mechanism underlying the physiological adaptation of purely aerobic workout, we investigated the effect of 2 months of training on nine males (17-22 year-old middle distance running agonistic athletes. Blood sample was collected in the morning to analyze: hematological parameters, lipid profile, liver function enzymes [glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, gamma-glutamyl transferase (γ-GT] and skeletal and myocardial markers of muscle damage [creatin kinase (CK and creatin kinase MB (CK-MB]. Endurance training, as it implies high oxygen consumption, should increase reactive oxygen species, but it has been shown that exercise leads to increased activation of antioxidant defenses. In fact, serum levels of γ-GT enzyme and total CK were not increased. On the other hand, a statistical significant reduction of CKMB has been observed. There were not variations in hematological parameters. As far as the anthropometric value is concerned, after two months of training there was a change in weight (P<0.0001. Finally, any oxidative and biological stress was highlighted in the middle distance runners but, since this is a preliminary study, it would be of interest to replicate the study on a larger sample.

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

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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.

The reliability of running economy expressed as oxygen cost and energy cost in trained distance runners.

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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.

Study of speed endurance middle distance runners

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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.

An empirical study of race times in recreational endurance runners.

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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.

Plantar Pressures During Long Distance Running: An Investigation of 10 Marathon Runners

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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.

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

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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.

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.

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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.

Increased Circulating Anti-inflammatory Cells in Marathon-trained Runners.

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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.

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...

The Relationship between Running Economy and Biomechanical Variables in Distance Runners

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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…

Skeletal muscle plasticity with marathon training in novice runners.

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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.

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

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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

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

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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.

Firm insoles effectively reduce hemolysis in runners during long distance running - a comparative study.

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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.

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

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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.

Different Training Modalities Improve Energy Cost and Performance in Master Runners

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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.

[Osteoarthritis from long-distance running?].

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Hohmann, E; Wörtler, K; Imhoff, A

2005-06-01

Long distance running has become a fashionable recreational activity. This study investigated the effects of external impact loading on bone and cartilage introduced by performing a marathon race. Seven beginners were compared to six experienced recreational long distance runners and two professional athletes. All participants underwent magnetic resonance imaging of the hip and knee before and after a marathon run. Coronal T1 weighted and STIR sequences were used. The pre MRI served as a baseline investigation and monitored the training effect. All athletes demonstrated normal findings in the pre run scan. All but one athlete in the beginner group demonstrated joint effusions after the race. The experienced and professional runners failed to demonstrate pathology in the post run scans. Recreational and professional long distance runners tolerate high impact forces well. Beginners demonstrate significant changes on the post run scans. Whether those findings are a result of inadequate training (miles and duration) warrant further studies. We conclude that adequate endurance training results in adaptation mechanisms that allow the athlete to compensate for the stresses introduced by long distance running and do not predispose to the onset of osteoarthritis. Significant malalignment of the lower extremity may cause increased focal loading of joint and cartilage.

Predictor variables for marathon race time in recreational female runners.

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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.

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

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

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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.

Acute Effects of Plyometric and Resistance Training on Running Economy in Trained Runners.

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Marcello, Richard T; Greer, Beau K; Greer, Anna E

2017-09-01

Marcello, RT, Greer, BK, and Greer, AE. Acute effects of plyometric and resistance training on running economy in trained runners. J Strength Cond Res 31(9): 2432-2437, 2017-Results regarding the acute effects of plyometrics and resistance training (PRT) on running economy (RE) are conflicting. Eight male collegiate distance runners (21 ± 1 years, 62.5 ± 7.8 ml·kg·min V[Combining Dot Above]O2 peak) completed V[Combining Dot Above]O2 peak and 1 repetition maximum (1RM) testing. Seven days later, subjects completed a 12 minutes RE test at 60 and 80% V[Combining Dot Above]O2 peak, followed by a PRT protocol or a rested condition of equal duration (CON). The PRT protocol consisted of 3 sets of 5 repetitions at 85% 1RM for barbell squats, Romanian deadlifts, and barbell lunges; the same volume was used for resisted lateral lunges, box jumps, and depth jumps. Subjects completed another RE test immediately after the treatments and 24 hours later. Subjects followed an identical protocol 6 days later with condition assignment reversed. Running economy was determined by both relative V[Combining Dot Above]O2 (ml·kg·min) and energy expenditure (EE) (kcal·min). There was a significant (p ≤ 0.05) between-trial increase in V[Combining Dot Above]O2 (37.1 ± 4.2 ml·kg·min PRT vs. 35.5 ± 3.9 ml·kg·min CON) and EE (11.4 ± 1.3 kcal·min PRT vs. 11.0 ± 1.4 kcal·min CON) immediately after PRT at 60% V[Combining Dot Above]O2 peak, but no significant changes were observed at 80% V[Combining Dot Above]O2 peak. Respiratory exchange ratio was significantly (p ≤ 0.05) reduced 24 hours after PRT (0.93 ± 0.0) as compared to the CON trial (0.96 ± 0.0) at 80% V[Combining Dot Above]O2 peak. Results indicate that high-intensity PRT may acutely impair RE in aerobically trained individuals at a moderate running intensity, but that the attenuation lasts less than 24 hours in duration.

The running pattern and its importance in running long-distance gears

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Jarosław Hoffman

2017-07-01

Full Text Available The running pattern is individual for each runner, regardless of distance. We can characterize it as the sum of the data of the runner (age, height, training time, etc. and the parameters of his run. Building the proper technique should focus first and foremost on the work of movement coordination and the power of the runner. In training the correct running steps we can use similar tools as working on deep feeling. The aim of this paper was to define what we can call a running pattern, what is its influence in long-distance running, and the relationship between the training technique and the running pattern. The importance of a running pattern in long-distance racing is immense, as the more distracted and departed from the norm, the greater the harm to the body will cause it to repetition in long run. Putting on training exercises that shape the technique is very important and affects the running pattern significantly.

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

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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.

Biomechanical factors associated with running economy and performance of elite Kenyan distance runners: A systematic review.

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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

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

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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.

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.

Relationship between Achilles tendon length and running performance in well-trained male endurance runners.

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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.

Protocol for evaluating the effects of a therapeutic foot exercise program on injury incidence, foot functionality and biomechanics in long-distance runners: a randomized controlled trial.

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Matias, Alessandra B; Taddei, Ulisses T; Duarte, Marcos; Sacco, Isabel C N

2016-04-14

Overall performance, particularly in a very popular sports activity such as running, is typically influenced by the status of the musculoskeletal system and the level of training and conditioning of the biological structures. Any change in the musculoskeletal system's biomechanics, especially in the feet and ankles, will strongly influence the biomechanics of runners, possibly predisposing them to injuries. A thorough understanding of the effects of a therapeutic approach focused on feet biomechanics, on strength and functionality of lower limb muscles will contribute to the adoption of more effective therapeutic and preventive strategies for runners. A randomized, prospective controlled and parallel trial with blind assessment is designed to study the effects of a "ground-up" therapeutic approach focused on the foot-ankle complex as it relates to the incidence of running-related injuries in the lower limbs. One hundred and eleven (111) healthy long-distance runners will be randomly assigned to either a control (CG) or intervention (IG) group. IG runners will participate in a therapeutic exercise protocol for the foot-ankle for 8 weeks, with 1 directly supervised session and 3 remotely supervised sessions per week. After the 8-week period, IG runners will keep exercising for the remaining 10 months of the study, supervised only by web-enabled software three times a week. At baseline, 2 months, 4 months and 12 months, all runners will be assessed for running-related injuries (primary outcome), time for the occurrence of the first injury, foot health and functionality, muscle trophism, intrinsic foot muscle strength, dynamic foot arch strain and lower-limb biomechanics during walking and running (secondary outcomes). This is the first randomized clinical trial protocol to assess the effect of an exercise protocol that was designed specifically for the foot-and-ankle complex on running-related injuries to the lower limbs of long-distance runners. We intend to show

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

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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.

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

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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.

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

Effect of tapering after a period of high-volume sprint interval training on running performance and muscular adaptations in moderately trained runners

DEFF Research Database (Denmark)

Skovgaard, Casper; Almquist, Nicki Winfield; Kvorning, Thue

2018-01-01

The effect of tapering following a period of high-volume sprint interval training (SIT) and a basic volume of aerobic training on performance and muscle adaptations in moderately trained runners was examined. Eleven (8 males, 3 females) runners (maximum oxygen uptake (VO2-max): 56.8±2.9 mL·min(-1...... running test at 90% of vVO2-max to exhaustion (RRT). In addition, a biopsy from m. vastus lateralis was obtained at rest. Performance during RRT was better (P... at 60% of vVO2-max was lower (P

Mixed maximal and explosive strength training in recreational endurance runners.

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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.

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...

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.

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.

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.

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 ...

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.

The GRONORUN study: is a graded training program for novice runners effective in preventing running related injuries? Design of a Randomized Controlled Trial

Directory of Open Access Journals (Sweden)

Pepping Gert-Jan

2007-03-01

Full Text Available Abstract Background Running is a popular form of recreational exercise. Beside the positive effects of running on health and fitness, the risk of a running related injury has to be considered. The incidence of injuries in runners is high and varies from 30–79%. However, few intervention studies on prevention of running related injuries have been performed and none of these studies involved novice runners. Methods GRONORUN (Groningen Novice Running is a two armed randomized controlled trial, comparing the effects of two different training programs for novice runners on the incidence of running related injuries. Participants are novice runners, who want to train for a four mile running event. The control group will train according a standard 8 week training program. The intervention group will use a more gradual, 13 week training program which is based on "the ten percent training rule". During the thirteen week follow up participants register information on running and RRI's in an internet based running log. The primary outcome measure is RRI. An injury is defined as a musculoskeletal ailment of the lower extremity or back, causing a restriction of running for at least one week. Discussion The GRONORUN trial is the first randomized controlled trial to study a preventive intervention in novice runners. Many different training programs for novice runners are offered, but none are evidence based.

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

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.

Time-course changes of oxidative stress response to high-intensity discontinuous training versus moderate-intensity continuous training in masters runners.

Directory of Open Access Journals (Sweden)

Alessandra Vezzoli

Full Text Available Beneficial systemic effects of regular physical exercise have been demonstrated to reduce risks of a number of age-related disorders. Antioxidant capacity adaptations are amongst these fundamental changes in response to exercise training. However, it has been claimed that acute physical exercise performed at high intensity (>60% of maximal oxygen uptake may result in oxidative stress, due to reactive oxygen species being generated excessively by enhanced oxygen consumption. The aim of this study was to evaluate the effect of high-intensity discontinuous training (HIDT, characterized by repeated variations of intensity and changes of redox potential, on oxidative damage. Twenty long-distance masters runners (age 47.8 ± 7.8 yr on the basis of the individual values of gas exchange threshold were assigned to a different 8-weeks training program: continuous moderate-intensity training (MOD, n = 10 or HIDT (n = 10. In both groups before (PRE and after (POST training we examined the following oxidative damage markers: thiobarbituric acid reactive substances (TBARS as marker of lipid peroxidation; protein carbonyls (PC as marker of protein oxidation; 8-hydroxy-2-deoxy-guanosine (8-OH-dG as a biomarker of DNA base modifications; and total antioxidant capacity (TAC as indicator of the overall antioxidant system. Training induced a significant (p<0.05 decrease in resting plasma TBARS concentration in both MOD (7.53 ± 0.30 and 6.46 ± 0.27 µM, PRE and POST respectively and HIDT (7.21 ± 0.32 and 5.85 ± 0.46 µM, PRE and POST respectively. Resting urinary 8-OH-dG levels were significantly decreased in both MOD (5.50 ± 0.66 and 4.16 ± 0.40 ng mg(-1creatinine, PRE and POST respectively and HIDT (4.52 ± 0.50 and 3.18 ± 0.34 ng mg(-1creatinine, PRE and POST respectively. Training both in MOD and HIDT did not significantly modify plasma levels of PC. Resting plasma TAC was reduced in MOD while no significant changes were observed in HIDT. In conclusion

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.

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.

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....

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...

Sports injuries in Finnish elite cross-country skiers, swimmers, long-distance runners and soccer players

OpenAIRE

Ristolainen, Leena

2011-01-01

In sports with different exercise-loading characteristics, acute and overuse injury profiles and gender differences in injuries were investigated. In addition, trainingrelated risk factors for overuse injuries in endurance athletes were studied. This twelve-month retrospective questionnaire study comprised Finnish elite crosscountry skiers (n=149), swimmers (n=154), long-distance runners (n=143) and soccer players (n=128) aged 15–35 years. Questionnaires were sent to the athlet...

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.

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 ...

Genetic aspects of athletic performance: the African runners phenomenon

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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

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.

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

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.

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.

a case series in habitual distance runners

African Journals Online (AJOL)

muscle injury, aponeurotic tears, ligament injuries, tendinopathy and evaluation of soft tissue ... the point of preventing visualisation of sections of the vessel lumen. (Figure 6). ... 11 constant, then intermittent. Short distances ... Gielen S, Schuler G, Adams V. Cardiovascular effects of exercise training: molecular mechanisms.

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

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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.

Effects of high intensity training and continuous endurance training on aerobic capacity and body composition in recreationally active runners.

Science.gov (United States)

Hottenrott, Kuno; Ludyga, Sebastian; Schulze, Stephan

2012-01-01

The aim of the study was to examine the effects of two different training programs (high-intensity-training vs. continuous endurance training) on aerobic power and body composition in recreationally active men and women and to test whether or not participants were able to complete a half marathon after the intervention period. Thirty-four recreational endurance runners were randomly assigned either to a Weekend-Group (WE, n = 17) or an After-Work- Group (AW, n = 17) for a 12 week-intervention period. WE weekly completed 2 h 30 min of continuous endurance running composed of 2 sessions on the weekend. In contrast, AW performed 4 30 min sessions of high intensity training and an additional 30 min endurance run weekly, always after work. During an exhaustive treadmill test aerobic power was measured and heart rate was continuously recorded. Body composition was assessed using bio-impedance. Following the intervention period all subjects took part in a half-marathon. AW significantly improved peak oxygen uptake (VO2 peak) from 36.8 ± 4.5 to 43.6 ± 6.5 [mL.min(-1).kg(-1)], velocity at lactate threshold (VLT) from 9.7 ± 2.2 to 11.7 ± 1.8 [km.h(-1)] and visceral fat from 5.6 ± 2.2 to 4.7 ± 1.9 In WE VO2 peak signifi-cantly increased from 38.8 ± 5.0 to 41.5 ± 6.0 [mL.min(-1).kg(-1)], VLT from 9.9 ± 1.3 to 11.2 ± 1.7 [km.h(-1)] and visceral fat was reduced from 5.7 ± 2.1 to 5.4 ± 1.9 (p marathon with no significant differences in performance (p = 0.63). Short, intensive endurance training sessions of about 30 min are effective in improving aerobic fitness in recreationally active runners. Key pointsContinuous endurance training and high intensity training lead to significant improvements of aerobic capacity and body compositionBoth training methods enable recreationally active runners to finish a half-marathonHigh intensity training is favorable to improve VO2 peak.

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

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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.

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

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

The occurrence of injuries in recreational runners in Wroclaw

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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.

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

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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.

The impact of different cross-training modalities on performance and injury-related variables in high school cross country runners.

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Paquette, Max R; Peel, Shelby A; Smith, Ross E; Temme, Mark; Dwyer, Jeffrey N

2017-11-29

There are many different types of aerobic cross-training modalities currently available. It is important to consider the effects that these different modalities have on running performance and injury risks. The purpose of this study was to compare movement quality, running economy and performance, injury-related biomechanical variables and, hip muscle strength before and after training with different cross-training modalities in high school runners. Thirty-one high school male runners trained for four weeks in one of three cross-training modalities, in addition to a running-only (RUN, n=9) group, for which training sessions replaced two easy runs per week: cycling (CYCLE; n=6), indoor elliptical (ELLIP; n=7) and, outdoor elliptical bike (EBIKE; n=9). Functional movement screen (FMS), running economy (RE), 3,000m performance, hip kinematics, hip muscle strength were assessed. Paired t-tests and Cohen's d effect sizes were used to assess mean differences for each variable before and after training within each group. EBIKE training was the only modality that improved FMS scores (d = 1.36) and RE before and after training (d = 0.48). All groups showed improvements in 3,000m performance but large effects were only found for the CYCLE (d = 1.50) and EBIKE (d = 1.41) groups. RUN (d = 1.25), CYCLE (d = 1.17) and, EBIKE (d = 0.82) groups showed improvements in maximal hip extensor strength. Outdoor cycling and elliptical bike cross-training may be the most effective cross-training modalities to incorporate in early season training to improve running performance in high school runners.

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

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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.

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

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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.

Shorter Ground Contact Time and Better Running Economy: Evidence From Female Kenyan Runners.

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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.

The NLstart2run study: Training-related factors associated with running-related injuries in novice runners.

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

2016-08-01

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 and running-related injuries in novice runners, taking the time varying nature of these training-related factors into account. Prospective cohort study. 1696 participants completed weekly diaries on running exposure and injuries during a 6-week running program for novice runners. Total running volume (min), frequency and mean intensity (Rate of Perceived Exertion) were calculated for the seven days prior to each training session. The association of these time-varying variables with injury was determined in an extended Cox regression analysis. The results of the multivariable analysis showed that running with a higher intensity in the previous week was associated with a higher injury risk. Running frequency was not significantly associated with injury, however a trend towards running three times per week being more hazardous than two times could be observed. Finally, lower running volume was associated with a higher risk of sustaining an injury. These results suggest that running more than 60min at a lower intensity is least injurious. This finding is contrary to our expectations and is presumably the result of other factors. Therefore, the findings should not be used plainly as a guideline for novices. More research is needed to establish the person-specific training patterns that are associated with injury. Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

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

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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 ...

Dietary supplement usage and motivation in Brazilian road runners.

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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.

Gastrointestinal disturbances in marathon runners.

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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.

THE EFFECT OF STEP RATE MANIPULATION ON FOOT STRIKE PATTERN OF LONG DISTANCE RUNNERS.

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Allen, Darrell J; Heisler, Hollie; Mooney, Jennifer; Kring, Richard

2016-02-01

running shoes. If changing the foot strike pattern is the main goal, other gait re-training methods may be needed to make a change from a heel strike to a non-heel strike pattern. Step rate manipulation shows a progressive reduction of foot inclination angle at 5%, 10%, and 15% above preferred step rate which reduces the severity of the heel strike at initial contact. Step rate manipulation of at least +10% above preferred may be an effective running gait retraining method for clinicians to decrease the severity of heel strike and possibly assist a runner to change to a non-heel strike pattern. 3.

Post-analysis methods for lactate threshold depend on training intensity and aerobic capacity in runners. An experimental laboratory study

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Tiago Lazzaretti Fernandes

Full Text Available ABSTRACT CONTEXT AND OBJECTIVE: This study aimed to evaluate different mathematical post-analysis methods of determining lactate threshold in highly and lowly trained endurance runners. DESIGN AND SETTING: Experimental laboratory study, in a tertiary-level public university hospital. METHOD: Twenty-seven male endurance runners were divided into two training load groups: lowly trained (frequency < 4 times per week, < 6 consecutive months, training velocity ≥ 5.0 min/km and highly trained (frequency ≥ 4 times per week, ≥ 6 consecutive months, training velocity < 5.0 min/km. The subjects performed an incremental treadmill protocol, with 1 km/h increases at each subsequent 4-minute stage. Fingerprint blood-lactate analysis was performed at the end of each stage. The lactate threshold (i.e. the running velocity at which blood lactate levels began to exponentially increase was measured using three different methods: increase in blood lactate of 1 mmol/l at stages (DT1, absolute 4 mmol/l blood lactate concentration (4 mmol, and the semi-log method (semi-log. ANOVA was used to compare different lactate threshold methods and training groups. RESULTS: Highly trained athletes showed significantly greater lactate thresholds than lowly trained runners, regardless of the calculation method used. When all the subject data were combined, DT1 and semi-log were not different, while 4 mmol was significantly lower than the other two methods. These same trends were observed when comparing lactate threshold methods in the lowly trained group. However, 4 mmol was only significantly lower than DT1 in the highly trained group. CONCLUSION: The 4 mmol protocol did not show lactate threshold measurements comparable with DT1 and semi-log protocols among lowly trained athletes.

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

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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.

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

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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

Increases in .VO2max with "live high-train low" altitude training: role of ventilatory acclimatization.

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Wilhite, Daniel P; Mickleborough, Timothy D; Laymon, Abigail S; Chapman, Robert F

2013-02-01

The purpose of this study was to estimate the percentage of the increase in whole body maximal oxygen consumption (.VO(2max)) that is accounted for by increased respiratory muscle oxygen uptake after altitude training. Six elite male distance runners (.VO(2max) = 70.6 ± 4.5 ml kg(-1) min(-1)) and one elite female distance runner (.VO(2max)) = 64.7 ml kg(-1) min(-1)) completed a 28-day "live high-train low" training intervention (living elevation, 2,150 m). Before and after altitude training, subjects ran at three submaximal speeds, and during a separate session, performed a graded exercise test to exhaustion. A regression equation derived from published data was used to estimate respiratory muscle .VO(2) (.VO(2RM)) using our ventilation (.VE) values. .VO(2RM) was also estimated retrospectively from a larger group of distance runners (n = 22). .VO(2max) significantly (p altitude (196 ± 59 ml min(-1)), while (.VE) at .VO(2max) also significantly (p altitude (201 ± 36 ml min(-1)), along with a 10.8 ± 2.1 l min(-1) increase in (.VE), thus requiring an estimated 27 % of Δ .VO(2max) Our data suggest that a substantial portion of the improvement in .VO(2max) with chronic altitude training goes to fuel the respiratory muscles as opposed to the musculature which directly contributes to locomotion. Consequently, the time-course of decay in ventilatory acclimatization following return to sea-level may have an impact on competitive performance.

[MRI changes of Achilles tendon and hindfoot in experienced runners and beginners during training and after a (half)-marathon competition].

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Freund, W; Billich, C; Brambs, H-J; Weber, F; Schütz, U H

2011-08-01

Marathon running is gaining in popularity. Its benefits regarding the cardiovascular system as well as the metabolism are beyond doubt. However, whether or not there are detrimental side effects to the musculoskeletal system such as wear and tear is an unsolved question. We therefore prospectively looked at beginners and experienced runners at a city marathon during training and after the competition for lesions to the Achilles tendon (AT) or hindfoot. 73 healthy subjects were prospectively included in our study. They were recruited from the applicants of the city marathon or half-marathon. They underwent an initial clinical orthopaedic as well as three magnetic resonance (MRI) examinations. The MRI were conducted at the time point of study enrolment, near the end of training and directly (up to 72 hours) after the run. MRI evaluation (fat saturated T (2)-weighted sagittal STIR sequence) was performed by two independent experienced radiologists blinded to the clinical context. The results were compared for subgroups of runners, also a factorial analysis was performed. Statistical results were deemed significant for p ≤ 0.05. 32 women and 41 men were included. In the end there were 53 finishers and 20 non-finishers; 28 seasoned runners and 25 novices. 57 runners had no foot complaints, while 14 had foot pain during training and 13 during the marathon. Mean body weight was 71.6 kg, height was 173 cm, age was 40.2 years. Mean AT diameter was 7.0 mm and showed no change during training or after the marathon. There was no significant influence of gender on other variables investigated. There was a significant and positive correlation between AT diameter and weight (r = 0.37), also AT and height (r = 0.34), while there was negative correlation between height and signal intensity of calcaneus (r = -0.50). The signal intensity of the AT decreased during training. The signal intensity of the calcaneus decreased from inclusion until after the marathon

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.)

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

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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.

Improvement in Running Economy after 6 Weeks of Plyometric Training.

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Turner, Amanda M.; Owings, Matt; Schwane, James A.

2003-01-01

Investigated whether a 6-week regimen of plyometric training would improve running economy. Data were collected on 18 regular but not highly trained distance runners who participated in either regular running training or plyometric training. Results indicated that 6 weeks of plyometric training improved running economy at selected speeds in this…

The Effect of Step Frequency Training on a Male Runner with Patellofemoral Pain

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Shelley Payne

2016-10-01

Full Text Available Running is a very popular form of exercise. The most common site of injury for runners is the knee with patellofemoral pain being the most common complaint. Patellofemoral pain is described as pain around the patella that is worse with activities such as running, squatting, ascending or descending stairs, or sitting for long periods. Much of the recent work with the treatment of patellofemoral pain has involved strengthening of the hip musculature to reduce pain about the knee. However, the ability of these strengthening programs to change lower extremity mechanics or sustain long-term pain reduction has been unproven. More recently, researchers have started to examine the impact of step frequency modification on the forces encountered in the lower extremity, and specifically about the patellofemoral joint. The purpose of this study was to examine the short term effects of step frequency training in a recreational runner with PFP. Methods: This was a single-subject case study design. The subject completed a pre- and post-training assessment to determine the preferred step frequency. The subject also completed a Visual Analog Scale (VAS and a Lower Extremity Functional Scale (LEFS. Results: After the initial evaluation, the subject completed training 2 times per week for 4 weeks using auditory feedback to increase their step frequency by 5% above their preferred step frequency. The subject experienced a decrease in pain as measured by the VAS and an increase in function as measured by the LEFS across the 4 week training. Discussion: Although the results of this case study may not be generalized, the positive findings support additional research to determine both the short and long-term effects of step frequency training on PFP.

Bioenergetic constraints on tactical decision making in middle distance running.

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Jones, A M; Whipp, B J

2002-04-01

The highest velocity that a runner can sustain during middle distance races is defined by the intersection of the runner's individual velocity-time curve and the distance-time curve. The velocity-time curve is presumably fixed at the onset of a race; however, whereas the race distance is ostensibly fixed, the actual distance-time curve is not. That is, it is possible for a runner to run further than the race distance if he or she runs wide on bends in track races. In this instance, the point of intersection of the individual velocity-time curve and the distance-time curve will move downwards and to the right, reducing the best average velocity that can be sustained for the distance. To illustrate this point, the race tactics used by the gold and silver medallists at 800 m and 5000 m in the Sydney Olympics were analysed. The paths taken by the runners were carefully tracked and the total distance they covered during the races and the average velocity they sustained over the distances they actually covered were calculated. In both the Olympic 800 m and 5000 m finals, for example, the winner was not the runner who ran at the highest average velocity in the race. Rather, the winners of these races were able to husband their metabolic resources to better effect by running closer to the actual race distance. Race results in middle distance running events are dependent not just on the energetic potential of the runners at the start of the race and their strategy for pace allocation, but also on the effect of their tactical approach to positioning on the total distance covered in the race. Middle distance runners should be conscious of minimising the distance covered in races if they wish to optimise their performance.

Relationship between cytokines and running economy in marathon runners

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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.

Risk factors for lower extremity injuries among half marathon and marathon runners of the Lage Landen Marathon Eindhoven 2012: A prospective cohort study in the Netherlands.

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van Poppel, D; de Koning, J; Verhagen, A P; Scholten-Peeters, G G M

2016-02-01

To determine risk factors for running injuries during the Lage Landen Marathon Eindhoven 2012. Prospective cohort study. Population-based study. This study included 943 runners. Running injuries after the Lage Landen Marathon. Sociodemographic and training-related factors as well as lifestyle factors were considered as potential risk factors and assessed in a questionnaire 1 month before the running event. The association between potential risk factors and injuries was determined, per running distance separately, using univariate and multivariate logistic regression analysis. In total, 154 respondents sustained a running injury. Among the marathon runners, in the univariate model, body mass index ≥ 26 kg/m(2), ≤ 5 years of running experience, and often performing interval training, were significantly associated with running injuries, whereas in the multivariate model only ≤ 5 years of running experience and not performing interval training on a regular basis were significantly associated with running injuries. Among marathon runners, no multivariate model could be created because of the low number of injuries and participants. This study indicates that interval training on a regular basis may be recommended to marathon runners to reduce the risk of injury. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Predictor Variables for Marathon Race Time in Recreational Female Runners

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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...

Health and economic burden of running-related injuries in runners training for an event: A prospective cohort study.

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Hespanhol Junior, L C; van Mechelen, W; Postuma, E; Verhagen, E

2016-09-01

Prospective running-related injury (RRI) data from runners training for an event are scarce, especially with regard to RRI-associated costs. Therefore, the aim of this study was to investigate the prevalence and economic burden of RRIs in runners participating in an organized training program preparing them for an event. This was a prospective cohort study with 18 weeks of follow-up. Individuals aged 18 or older and registered to participate in an organized running program were eligible. Follow-up surveys were sent every 2 weeks to collect data about running exposure, RRIs, and costs. Of the 161 potential participants, 53 (32.9%) were included in this study. A total of 32 participants reported 41 RRIs. The mean prevalence during follow-up was 30.8% [95% confidence interval (CI) 25.6-36.0%]. Overuse was the main mechanism of RRI (85.4%, n = 35). An RRI was estimated to have an economic burden of €57.97 (95% CI €26.17-94.00) due to healthcare utilization (direct costs) and €115.75 (95% CI €10.37-253.73) due to absenteeism from paid work (indirect costs). These results indicate that the health and economic burden of RRIs may be considered significant for public health. Therefore, prevention programs are needed for runners participating in organized training programs. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Ground reaction forces and kinematics in distance running in older-aged men.

Science.gov (United States)

Bus, Sicco A

2003-07-01

The biomechanics of distance running has not been studied before in older-aged runners but may be different than in younger-aged runners because of musculoskeletal degeneration at older age. This study aimed at determining whether the stance phase kinematics and ground reaction forces in running are different between younger- and older-aged men. Lower-extremity kinematics using three-dimensional motion analysis and ground reaction forces (GRF) using a force plate were assessed in 16 older-aged (55-65 yr) and 13 younger-aged (20-35 yr) well-trained male distance runners running at a self-selected (SRS) and a controlled (CRS) speed of 3.3 m.s-1. The older subjects ran at significantly lower self-selected speeds than the younger subjects (mean 3.34 vs 3.77 m.s-1). In both speed conditions, the older runners exhibited significantly more knee flexion at heel strike and significantly less knee flexion and extension range of motion. No age group differences were present in subtalar joint motion. Impact peak force (1.91 vs 1.70 BW) and maximal initial loading rate (107.5 vs 85.5 BW.s-1) were significantly higher in the older runners at the CRS. Maximal peak vertical and anteroposterior forces and impulses were significantly lower in the older runners at the SRS. The biomechanics of running is different between older- and younger-aged runners on several relevant parameters. The larger impact peak force and initial loading rate indicate a loss of shock-absorbing capacity in the older runners. This may increase their susceptibility to lower-extremity overuse injuries. Moreover, it emphasizes the focus on optimizing cushioning properties in the design and prescription of running shoes and suggests that older-aged runners should be cautious with running under conditions of high impact.

Effects of a concurrent strength and endurance training on running performance and running economy in recreational marathon runners.

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Ferrauti, Alexander; Bergermann, Matthias; Fernandez-Fernandez, Jaime

2010-10-01

The purpose of this study was to investigate the effects of a concurrent strength and endurance training program on running performance and running economy of middle-aged runners during their marathon preparation. Twenty-two (8 women and 14 men) recreational runners (mean ± SD: age 40.0 ± 11.7 years; body mass index 22.6 ± 2.1 kg·m⁻²) were separated into 2 groups (n = 11; combined endurance running and strength training program [ES]: 9 men, 2 women and endurance running [E]: 7 men, and 4 women). Both completed an 8-week intervention period that consisted of either endurance training (E: 276 ± 108 minute running per week) or a combined endurance and strength training program (ES: 240 ± 121-minute running plus 2 strength training sessions per week [120 minutes]). Strength training was focused on trunk (strength endurance program) and leg muscles (high-intensity program). Before and after the intervention, subjects completed an incremental treadmill run and maximal isometric strength tests. The initial values for VO2peak (ES: 52.0 ± 6.1 vs. E: 51.1 ± 7.5 ml·kg⁻¹·min⁻¹) and anaerobic threshold (ES: 3.5 ± 0.4 vs. E: 3.4 ± 0.5 m·s⁻¹) were identical in both groups. A significant time × intervention effect was found for maximal isometric force of knee extension (ES: from 4.6 ± 1.4 to 6.2 ± 1.0 N·kg⁻¹, p marathon running velocities (2.4 and 2.8 m·s⁻¹) and submaximal blood lactate thresholds (2.0, 3.0, and 4.0 mmol·L⁻¹). Stride length and stride frequency also remained unchanged. The results suggest no benefits of an 8-week concurrent strength training for running economy and coordination of recreational marathon runners despite a clear improvement in leg strength, maybe because of an insufficient sample size or a short intervention period.

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.

Metabolic factors limiting performance in marathon runners.

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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.

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.

The effect of footwear on running performance and running economy in distance runners.

Science.gov (United States)

Fuller, Joel T; Bellenger, Clint R; Thewlis, Dominic; Tsiros, Margarita D; Buckley, Jonathan D

2015-03-01

The effect of footwear on running economy has been investigated in numerous studies. However, no systematic review and meta-analysis has synthesised the available literature and the effect of footwear on running performance is not known. The aim of this systematic review and meta-analysis was to investigate the effect of footwear on running performance and running economy in distance runners, by reviewing controlled trials that compare different footwear conditions or compare footwear with barefoot. The Web of Science, Scopus, MEDLINE, CENTRAL (Cochrane Central Register of Controlled Trials), EMBASE, AMED (Allied and Complementary Medicine), CINAHL and SPORTDiscus databases were searched from inception up until April 2014. Included articles reported on controlled trials that examined the effects of footwear or footwear characteristics (including shoe mass, cushioning, motion control, longitudinal bending stiffness, midsole viscoelasticity, drop height and comfort) on running performance or running economy and were published in a peer-reviewed journal. Of the 1,044 records retrieved, 19 studies were included in the systematic review and 14 studies were included in the meta-analysis. No studies were identified that reported effects on running performance. Individual studies reported significant, but trivial, beneficial effects on running economy for comfortable and stiff-soled shoes [standardised mean difference (SMD) beneficial effect on running economy for cushioned shoes (SMD = 0.37; P beneficial effect on running economy for training in minimalist shoes (SMD = 0.79; P beneficial effects on running economy for light shoes and barefoot compared with heavy shoes (SMD running was identified (P running economy. Certain models of footwear and footwear characteristics can improve running economy. Future research in footwear performance should include measures of running performance.

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

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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.

Trabecular bone in the calcaneus of runners.

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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

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

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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.

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.

Predictors of running-related injuries in novice runners enrolled in a systematic training program: a prospective cohort study.

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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.

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

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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.

10-20-30 training increases performance and lowers blood pressure and VEGF in runners

DEFF Research Database (Denmark)

Gliemann, Lasse; Gunnarsson, Thomas Gunnar Petursson; Hellsten, Ylva

2015-01-01

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......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......-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...

Ultramarathon runners: nature or nurture?

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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.

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...

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.

Comparison of Brain-Derived Neurotrophic Factor (BDNF and Insulin-like Growth Factor 1 (IGF-1 Responses to Different Endurance Training Intensities in Runner Men

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M. Habibian

2017-04-01

Full Text Available Aims: Blood neurotrophins, such as Brain-Derived Neurotrophic Factor (BDNF and Insulin-like Growth Factor 1 (IGF-1, mediate exercise- induced health benefits in humans. The purpose of this study was to compare the response of BDNF and IGF-1 to different endurance training intensities in runner men. Materials & Methods: In this semi-experimental study with pre-test-posttest design in 2015, 10 people of male runners from Gorgan were selected through purposeful and accessible sampling. The endurance training protocol was 6 km running with moderate (70-75% of heart rate reserve or severe (80-85% of heart rate reserve intensity, which was performed within a week's interval. Fasting blood samples were collected before and immediately after both acute training sessions and serum levels of BDNF and IGF-1 were measured by ELISA and radioimmunoassay enzyme. Data were analyzed by SPSS 20 software using independent t-test and paired t-test. Findings: Both acute endurance training significantly increased serum levels of BDNF and IGF-1 in runners, but high intensity endurance exercises increased BDNF levels in comparison with moderate intensity (p0.05. Conclusion: Serum BDNF response in endurance athletes is affected by the intensity of exercise, so that the effect of high intensity endurance training on BDNF levels is greater than moderate intensity exercise, but the response of IGF-1 to acute endurance training is independent of the intensity of exercise.

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…

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

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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.

The GRONORUN 2 study: effectiveness of a preconditioning program on preventing running related injuries in novice runners. The design of a randomized controlled trial.

Science.gov (United States)

Bredeweg, Steef W; Zijlstra, Sjouke; Buist, Ida

2010-09-01

Distance running is a popular recreational exercise. It is a beneficial activity for health and well being. However, running may also cause injuries, especially of the lower extremities. In literature there is no agreement what intrinsic and extrinsic factors cause running related injuries (RRIs). In theory, most RRIs are elicited by training errors, this too much, too soon. In a preconditioning program runners can adapt more gradually to the high mechanical loads of running and will be less susceptible to RRIs. In this study the effectiveness of a 4-week preconditioning program on the incidence of RRIs in novice runners prior to a training program will be studied. The GRONORUN 2 (Groningen Novice Running) study is a two arm randomized controlled trial studying the effect of a 4-week preconditioning (PRECON) program in a group of novice runners. All participants wanted to train for the recreational Groningen 4-Mile running event. The PRECON group started a 4-week preconditioning program with walking and hopping exercises 4 weeks before the start of the training program. The control (CON) and PRECON group started a frequently used 9-week training program in preparation for the Groningen 4-Mile running event.During the follow up period participants registered their running exposure, other sporting activities and running related injuries in an Internet based running log. The primary outcome measure was the number of RRIs. RRI was defined as a musculoskeletal ailment or complaint of the lower extremities or back causing a restriction on running for at least three training sessions. The GRONORUN 2 study will add important information to the existing running science. The concept of preconditioning is easy to implement in existing training programs and will hopefully prevent RRIs especially in novice runners. The Netherlands National Trial Register NTR1906. The NTR is part of the WHO Primary Registries.

Hypoxanthine as a predictor of performance in highly trained athletes.

Science.gov (United States)

Zieliński, J; Krasińska, B; Kusy, K

2013-12-01

Purine metabolism reflects the exercise-induced muscle adaptations and training status. This study evaluated the utility of plasma hypoxanthine in the prediction of actual sport performance. We studied male athletes: 28 triathletes (21.4±2.9 years), 12 long-distance runners (23.2±1.9 years), 13 middle-distance runners (22.9±1.8 years) and 18 sprinters (22.0±2.7 years). Season-best race times were considered, achieved over standard triathlon, 5 000 m, 1 500 m and 100 m, respectively. Incremental treadmill test was administered to determine maximum and "threshold" oxygen uptake. Resting and post-exercise plasma concentrations of hypoxanthine, xanthine, uric acid and lactate were measured as well as resting erythrocyte hypoxanthine-guanine phosphoribosyltransferase activity. Simple and multiple regression analyses were used to identify significant contributors to the variance in performance. Hypoxanthine considered alone explained more variance in triathletes, long-distance runners, middle-distance runners and sprinters (r 2=0.81, 0.81, 0.88 and 0.78, respectively) than models based on aerobic capacity and lactate (R 2=0.51, 0.37, 0.59 and 0.31, respectively). Combining purine metabolites and cardiorespiratory variables resulted in the best prediction (R 2=0.86, 0.93, 0.93 and 0.91; r=0.93, 0.96, 0.96 and 0.95, respectively). In summary, hypoxanthine is a strong predictor of performance in highly trained athletes and its prediction ability is very high regardless of sport specialization, spanning the continuum from speed-power to endurance disciplines. © Georg Thieme Verlag KG Stuttgart · New York.

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...

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.

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

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

THE EFFECTS OF SODIUM CITRATE INGESTION ON METABOLISM AND 1500-M RACING TIME IN TRAINED FEMALE RUNNERS

Directory of Open Access Journals (Sweden)

Vahur Ööpik

2008-03-01

Full Text Available The purpose of the study was to assess the effects of sodium citrate ingestion on the metabolic response to exercise and performance in a 1500-m competitive run in trained female middle-distance runners in field conditions. Seventeen athletes (mean (± SD aged 18.6 ± 2.5 years, VO2max 55.2 ± 7.6 ml·kg-1·min-1 competed in two 1500-m races following ingestion of 0.4 g·kg-1 body mass of sodium citrate (CIT and placebo (PLC - 1.0% solution of NaCl. The two substances, CIT and PLC were administered in 800 ml of solution in a randomly assigned double-blind crossover manner. Capillary blood samples were analysed for lactate, glucose, haemoglobin and haematocrit before administering the solutions (baseline as well as before and after both 1500-m races. The athletes' times for trials CIT and PLC were 321.4 ± 26.4 and 317.4 ± 22.5 s, respectively (p > 0.05. A greater relative increase in plasma volume after administering the experimental solution, an increased body mass (by 0.4 kg; p = 0.006 immediately before the race and a restrained increase in blood glucose concentration (by 2.5 ± 1.2 mmol·l-1 vs 3.4 ± 0.8 mmol·l-1; p = 0.002 during the race were observed in the CIT trial compared to the PLC. A significant relationship was observed between body mass of the subjects immediately before the race and performance time (r = 0.374; p = 0.029. There were no between-treatment differences in heart rate in any stage of the run or in blood lactate accumulation during the race (final concentration of lactate was 14.4 ± 3.0 mmol·l-1 and 13.4 ± 2.5 mmol·l-1 (p > 0.05 in the CIT and PLC trials, respectively. The results suggest that sodium citrate induces an increase in water retention before exercise and may modify carbohydrate metabolism in high intensity running, but does not improve performance in 1500-m competitive run in female middle-distance runners

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)

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.

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...

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.

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

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.

The Effects of a 10-day Altitude Training Camp at 1828 Meters on Varsity Cross-Country Runners.

Science.gov (United States)

Diebel, Sebastian R; Newhouse, Ian; Thompson, David S; Johnson, Vineet B K

2017-01-01

Altitude training has been shown to alter blood lactate (BL) levels due to alterations resulting from acclimatization. This study aims to estimate the impact of altitude training on BL changes immediately following an incremental treadmill test and during recovery before and after 10-day altitude training at approximately 1828 meters. Eight varsity cross-country runners performed an incremental treadmill test (ITT), pre and post-altitude training. Resting and post-warm-up BL values were recorded. During ITT, heart rate (HR), oxygen saturation (SpO2), and time to exhaustion were monitored. BL was also measured post-ITT at 0, 2, 4, 6, and 8 minutes. The average of all BL values was higher following altitude intervention (8.8 ± 4.6 mmol/L) compared to pre-intervention (7.4 ± 3.3 mmol/L). These differences were statistically significant ( t (6) = -2.40, p = .026). BL immediately (0 minutes) after the ITT was higher following the altitude intervention (13.6 ± 3.6 mmol/L) compared to pre-intervention (9.7 ± 3.8 mmol/L) and was statistically significant ( t (7) = -3.30, p = .006). Average HR during the ITT was lower following the altitude intervention (176.9 ± 11.1 bpm) compared to pre (187 ± 9.5 bpm), these differences were statistically significant ( t (28)= 18.07, p= altitude intervention at 1828 meters may benefit varsity cross-country runners. The higher post-exercise BL may be attributed to more anaerobic contributions. Lower HR may suggest a larger stroke volume and/or more efficient O2 carrying capacity.

EFFECTS OF HIGH INTENSITY TRAINING AND CONTINUOUS ENDURANCE TRAINING ON AEROBIC CAPACITY AND BODY COMPOSITION IN RECREATIONALLY ACTIVE RUNNERS

Directory of Open Access Journals (Sweden)

Kuno Hottenrott

2012-09-01

Full Text Available The aim of the study was to examine the effects of two different training programs (high-intensity-training vs. continuous endurance training on aerobic power and body composition in recreationally active men and women and to test whether or not participants were able to complete a half marathon after the intervention period. Thirty-four recreational endurance runners were randomly assigned either to a Weekend-Group (WE, n = 17 or an After-Work- Group (AW, n = 17 for a 12 week-intervention period. WE weekly completed 2 h 30 min of continuous endurance running composed of 2 sessions on the weekend. In contrast, AW performed 4 30 min sessions of high intensity training and an additional 30 min endurance run weekly, always after work. During an exhaustive treadmill test aerobic power was measured and heart rate was continuously recorded. Body composition was assessed using bio-impedance. Following the intervention period all subjects took part in a half-marathon. AW significantly improved peak oxygen uptake (VO2 peak from 36.8 ± 4.5 to 43.6 ± 6.5 [mL.min-1.kg-1], velocity at lactate threshold (VLT from 9.7 ± 2.2 to 11.7 ± 1.8 [km.h-1] and visceral fat from 5.6 ± 2.2 to 4.7 ± 1.9 In WE VO2 peak signifi-cantly increased from 38.8 ± 5.0 to 41.5 ± 6.0 [mL.min-1.kg-1], VLT from 9.9 ± 1.3 to 11.2 ± 1.7 [km.h-1] and visceral fat was reduced from 5.7 ± 2.1 to 5.4 ± 1.9 (p < 0.01. Only the improvements of VO2 peak were significantly greater in AW compared with WE (pre/post group interaction: F=15.4, p = 0.01, η2 = 0.36. Both groups completed a half marathon with no significant differences in performance (p = 0.63. Short, intensive endurance training sessions of about 30 min are effective in improving aerobic fitness in recreationally active runners

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.

long-distance runners

African Journals Online (AJOL)

Other problems are eating disorders and skeletal abnormalities, including re~ stress fractures and failure to reach peak bone mass.1. The BMD might be influenced by several variables, such as current men- strual status, menstrual history, body mass, functional loading, family history of osteoporosis, nutritional status, train ...

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.

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.

The GRONORUN 2 study: effectiveness of a preconditioning program on preventing running related injuries in novice runners. The design of a randomized controlled trial

Directory of Open Access Journals (Sweden)

Bredeweg Steef W

2010-09-01

Full Text Available Abstract Background Distance running is a popular recreational exercise. It is a beneficial activity for health and well being. However, running may also cause injuries, especially of the lower extremities. In literature there is no agreement what intrinsic and extrinsic factors cause running related injuries (RRIs. In theory, most RRIs are elicited by training errors, this too much, too soon. In a preconditioning program runners can adapt more gradually to the high mechanical loads of running and will be less susceptible to RRIs. In this study the effectiveness of a 4-week preconditioning program on the incidence of RRIs in novice runners prior to a training program will be studied. Methods/Design The GRONORUN 2 (Groningen Novice Running study is a two arm randomized controlled trial studying the effect of a 4-week preconditioning (PRECON program in a group of novice runners. All participants wanted to train for the recreational Groningen 4-Mile running event. The PRECON group started a 4-week preconditioning program with walking and hopping exercises 4 weeks before the start of the training program. The control (CON and PRECON group started a frequently used 9-week training program in preparation for the Groningen 4-Mile running event. During the follow up period participants registered their running exposure, other sporting activities and running related injuries in an Internet based running log. The primary outcome measure was the number of RRIs. RRI was defined as a musculoskeletal ailment or complaint of the lower extremities or back causing a restriction on running for at least three training sessions. Discussion The GRONORUN 2 study will add important information to the existing running science. The concept of preconditioning is easy to implement in existing training programs and will hopefully prevent RRIs especially in novice runners. Trial registration The Netherlands National Trial Register NTR1906. The NTR is part of the WHO Primary

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

Catharsis – Philosophical and Spiritual Aspects of Long-Distance Running

Directory of Open Access Journals (Sweden)

Nemec Marcel

2016-05-01

Full Text Available The purpose of the study was to identify and analyze the occurrence of cathartic states in a sample of long-distance runners. Data collected via questionnaires were used to evaluate quantitative variables complemented by heuristics while aiming at qualitatively categorize the areas of cathartic states in the context of philosophical and spiritual aspects of long-distance running. The study findings objectify philosophical and spiritual aspects affecting personalities of long-distance runners. The study findings have shown that catharsis represents a relevant philosophical and spiritual aspect affecting long-distance running. We assume that authentic experience of catharsis and its effects motivates runners to perform regular physical activity. The analysis of philosophical and spiritual aspects of long-distance running has revealed a multi-spectral holistic relevance based on the transfer affecting a specific way of life, spectrum of values, ethical personality traits, and also the quality of long-distance runners’ lives.

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.

Increased Prevalence of the IL-6-174C Genetic Polymorphism in Long Distance Swimmers.

Science.gov (United States)

Ben-Zaken, Sigal; Meckel, Yoav; Nemet, Dan; Kassem, Eias; Eliakim, Alon

2017-09-01

The IL-6 -174G/C single nucleotide polymorphism (SNP) functionally affects IL-6 activity, with the G-allele associated with increased IL-6 levels. The C-allele was found to be associated with exercise-induced skeletal muscle damage. The aim of the present study was to examine the association between the IL-6 -174G/C polymorphism and athletic performance among elite swimmers and runners. The study sample included 180 track and field athletes and 80 swimmers. Track and field athletes were assigned to three sub-groups: long-distance runners, middle-distance runners and short-distance runners. Swimmers were assigned to two subgroups: long-distance swimmers and short-distance swimmers. The control group consisted of 123 non-athletic healthy individuals. Genomic DNA was extracted from peripheral blood following a standard protocol. Genotyping was performed using polymerase chain reaction (PCR). The CC genotype and C-allele frequency were significantly higher in the long-distance swimmers (18 and 43%, respectively) compared to the long-distance runners (3 and 14%, respectively, p < 0.001); middle-distance runners (4 and 22%, respectively, p < 0.001); and controls (5 and 19%, respectively, p < 0.001). In addition, the CC genotype and C-allele frequency were significantly higher (p < 0.001) in long-distance swimmers compared to short-distance swimmers (18 versus 5% and 43 versus 29% for the CC genotype and C-allele frequency, respectively). The higher frequency of the C-allele and CC genotype among long-distance swimmers suggests that the rarity of exercise-associated rhabdomyolysis among swimmers is probably related to other sports-specific or water-related protective mechanisms. It is possible that swimming selection in talented endurance athletes who are C-allele carriers represents an example of genetically-dependent sports selection.

Increased Prevalence of the IL-6 -174C Genetic Polymorphism in Long Distance Swimmers

Directory of Open Access Journals (Sweden)

Ben-Zaken Sigal

2017-08-01

Full Text Available The IL-6 -174G/C single nucleotide polymorphism (SNP functionally affects IL-6 activity, with the G-allele associated with increased IL-6 levels. The C-allele was found to be associated with exercise-induced skeletal muscle damage. The aim of the present study was to examine the association between the IL-6 -174G/C polymorphism and athletic performance among elite swimmers and runners. The study sample included 180 track and field athletes and 80 swimmers. Track and field athletes were assigned to three sub-groups: long-distance runners, middle-distance runners and short-distance runners. Swimmers were assigned to two subgroups: long-distance swimmers and short-distance swimmers. The control group consisted of 123 non-athletic healthy individuals. Genomic DNA was extracted from peripheral blood following a standard protocol. Genotyping was performed using polymerase chain reaction (PCR. The CC genotype and C-allele frequency were significantly higher in the long-distance swimmers (18 and 43%, respectively compared to the long-distance runners (3 and 14%, respectively, p < 0.001; middle-distance runners (4 and 22%, respectively, p < 0.001; and controls (5 and 19%, respectively, p < 0.001. In addition, the CC genotype and C-allele frequency were significantly higher (p < 0.001 in long-distance swimmers compared to short-distance swimmers (18 versus 5% and 43 versus 29% for the CC genotype and C-allele frequency, respectively. The higher frequency of the C-allele and CC genotype among long-distance swimmers suggests that the rarity of exercise-associated rhabdomyolysis among swimmers is probably related to other sports-specific or water-related protective mechanisms. It is possible that swimming selection in talented endurance athletes who are C-allele carriers represents an example of genetically-dependent sports selection.

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 ...

Running more than three kilometers during the first week of a running regimen may be associated with increased risk of injury in obese novice runners

DEFF Research Database (Denmark)

Nielsen, R.O.; Bertelsen, Michael Lejbach; Parner, Erik Thorlund

2014-01-01

BACKGROUND: Training guidelines for novice runners are needed to reduce the risk of injury. The purpose of this study was to investigate whether the risk of injury varied in obese and non-obese individuals initiating a running program at different weekly distances. METHODS: A volunteer sample...... = high). Data was collected for three weeks for the six strata. The main outcome measure was running-related injury. RESULTS: Fifty-six runners sustained a running-related injury during the 3-week data collection. A significantly greater number of individuals with BMI>30 sustained injuries if they ran...... and BMI on additive scale was positive (11.7% [-3.6% to 27.0%], p=0.13). The number of obese individuals needed to change their running distance from high to low to avoid one injury was 8.5 [95%CI: 4.6 to 52]. CONCLUSIONS: Obese individuals were at greater risk of injury if they exceeded 3 km during...

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.

Long-term success and risk for marathon runners; Langzeiterfolg und Risiko der Marathonlaeufer

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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.)

Predictor variables for half marathon race time in recreational female runners

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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.

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.

A displaced stress fracture of the femoral neck in an adolescent female distance runner with female athlete triad: A case report

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Okamoto Shinichi

2010-03-01

Full Text Available Abstract This report presents a case of a displaced stress fracture of the femoral neck in an adolescent female distance runner with amenorrhea. Both reduction and internal fixation were performed early after the injury. At 24 months postoperatively, magnetic resonance imaging and bone scintigraphy showed no positive signs of femoral head necrosis and bone union was confirmed on plain X-ray. A medical examination for the presence of the signs of the female athlete triad by checking weight, calorie intake and menstrual cycles is most important to prevent such stress fractures. Athletes as well as their coaches or parents therefore need to understand female athlete triad.

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.

Changes on magnetic resonance tomography in the knee joints of marathon runners: a 10-year longitudinal study

International Nuclear Information System (INIS)

Krampla, Wolfgang W.; Newrkla, Stephan P.; Hruby, Walter F.; Kroener, Andreas H.

2008-01-01

The aim of the study was to evaluate long-term damage in the internal structures of the knee joints of recreational long-distance runners. Ten years after their participation in a baseline study concerning their knee joints, seven long-distance runners and one who had given up long-distance running were invited to participate in a repeat magnetic resonance imaging (MRI) investigation. The same evaluation criteria and the same technical equipment were used, and the results of the two investigations were compared. No adverse long-term consequences were observed in six of the seven active runners, regardless of pre-existing damage at the baseline investigation. In one case the arthrotic changes were progressive in nature. The person who had given up running presented with severe deterioration of the internal structures of the knee joint. Non-physiological maximal loads secondary to the marathon race do not cause any permanent damage in the internal structures of the knee joint in individuals without significant pre-existing damage. A disposition for premature arthrosis was not registered in the population investigated. A protective value of long distance running on the internal structures of the knee joint is discussed. (orig.)

Changes on magnetic resonance tomography in the knee joints of marathon runners: a 10-year longitudinal study

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Krampla, Wolfgang W.; Newrkla, Stephan P.; Hruby, Walter F. [Danube Hospital, Radiology Department, Vienna (Austria); Kroener, Andreas H. [Danube Hospital, Department of Orthopedic Surgery, Vienna (Austria)

2008-07-15

The aim of the study was to evaluate long-term damage in the internal structures of the knee joints of recreational long-distance runners. Ten years after their participation in a baseline study concerning their knee joints, seven long-distance runners and one who had given up long-distance running were invited to participate in a repeat magnetic resonance imaging (MRI) investigation. The same evaluation criteria and the same technical equipment were used, and the results of the two investigations were compared. No adverse long-term consequences were observed in six of the seven active runners, regardless of pre-existing damage at the baseline investigation. In one case the arthrotic changes were progressive in nature. The person who had given up running presented with severe deterioration of the internal structures of the knee joint. Non-physiological maximal loads secondary to the marathon race do not cause any permanent damage in the internal structures of the knee joint in individuals without significant pre-existing damage. A disposition for premature arthrosis was not registered in the population investigated. A protective value of long distance running on the internal structures of the knee joint is discussed. (orig.)

Enhanced Right-Chamber Remodeling in Endurance Ultra-Trail Athletes Compared to Marathon Runners Detected by Standard and Speckle-Tracking Echocardiography

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Kristian Ujka

2017-07-01

Full Text Available Background: Strenuous and endurance exercise training have been associated with morphological and functional heart remodeling. Two-dimensional speckle-tracking echocardiography (STE is a novel technique that allows an accurate quantification of global myocardium deformation. Our aim was to evaluate together left and right cardiac remodeling in different long-distance running athletes: marathon runners (42 km (M and endurance mountain runners (>300 Km (UT.Methods: A total of 92 athletes (70 males, 76% including 47 M [age 45 ± 7 years; training: 18 (9–53 years*days/week], 45 UT [age 42 ± 9, training: 30 (15–66 years*days/week] underwent conventional echocardiography and STE (Beyond Diogenes 2.0, AMID during the agonistic season.Results: Right ventricle (RV end-diastolic area (p = 0.026, fractional area changing (FAC (p = 0.008 and RV global longitudinal strain (GLS were significantly increasedin UT athletes. Furthermore, UT showed larger right atrium (RA volume (p = 0.03, reduced RA GLS and significantly increased RA global circumferential strain (GCS compared to M. After adjustment for age, sex, and HR as covariates, UT showed a reduced RA GLS (OR 0.907; CI 0.856–0.961 and increased RV FAC (OR 1.172; CI: 1.044–1.317 compared to M.Conclusion: Athletes enrolled in UT endurance activities showed RV and RA morphological and functional remodeling to increased preload in comparison with M runners characterized by increased RV FAC and reduced RA GLS. Follow-up studies are needed to better assess the long-term clinical impact of these modifications. 2D STE is a useful tool for investigating the deformation dynamic in different sports specialties.

Understanding Trail Runners' Activity on Online Community Forums: An Inductive Analysis of Discussion Topics.

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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.

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.

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

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

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.

Mean platelet volume (MPV) predicts middle distance running performance.

Science.gov (United States)

Lippi, Giuseppe; Salvagno, Gian Luca; Danese, Elisa; Skafidas, Spyros; Tarperi, Cantor; Guidi, Gian Cesare; Schena, Federico

2014-01-01

Running economy and performance in middle distance running depend on several physiological factors, which include anthropometric variables, functional characteristics, training volume and intensity. Since little information is available about hematological predictors of middle distance running time, we investigated whether some hematological parameters may be associated with middle distance running performance in a large sample of recreational runners. The study population consisted in 43 amateur runners (15 females, 28 males; median age 47 years), who successfully concluded a 21.1 km half-marathon at 75-85% of their maximal aerobic power (VO2max). Whole blood was collected 10 min before the run started and immediately thereafter, and hematological testing was completed within 2 hours after sample collection. The values of lymphocytes and eosinophils exhibited a significant decrease compared to pre-run values, whereas those of mean corpuscular volume (MCV), platelets, mean platelet volume (MPV), white blood cells (WBCs), neutrophils and monocytes were significantly increased after the run. In univariate analysis, significant associations with running time were found for pre-run values of hematocrit, hemoglobin, mean corpuscular hemoglobin (MCH), red blood cell distribution width (RDW), MPV, reticulocyte hemoglobin concentration (RetCHR), and post-run values of MCH, RDW, MPV, monocytes and RetCHR. In multivariate analysis, in which running time was entered as dependent variable whereas age, sex, blood lactate, body mass index, VO2max, mean training regimen and the hematological parameters significantly associated with running performance in univariate analysis were entered as independent variables, only MPV values before and after the trial remained significantly associated with running time. After adjustment for platelet count, the MPV value before the run (p = 0.042), but not thereafter (p = 0.247), remained significantly associated with running

Mean platelet volume (MPV predicts middle distance running performance.

Directory of Open Access Journals (Sweden)

Giuseppe Lippi

Full Text Available Running economy and performance in middle distance running depend on several physiological factors, which include anthropometric variables, functional characteristics, training volume and intensity. Since little information is available about hematological predictors of middle distance running time, we investigated whether some hematological parameters may be associated with middle distance running performance in a large sample of recreational runners.The study population consisted in 43 amateur runners (15 females, 28 males; median age 47 years, who successfully concluded a 21.1 km half-marathon at 75-85% of their maximal aerobic power (VO2max. Whole blood was collected 10 min before the run started and immediately thereafter, and hematological testing was completed within 2 hours after sample collection.The values of lymphocytes and eosinophils exhibited a significant decrease compared to pre-run values, whereas those of mean corpuscular volume (MCV, platelets, mean platelet volume (MPV, white blood cells (WBCs, neutrophils and monocytes were significantly increased after the run. In univariate analysis, significant associations with running time were found for pre-run values of hematocrit, hemoglobin, mean corpuscular hemoglobin (MCH, red blood cell distribution width (RDW, MPV, reticulocyte hemoglobin concentration (RetCHR, and post-run values of MCH, RDW, MPV, monocytes and RetCHR. In multivariate analysis, in which running time was entered as dependent variable whereas age, sex, blood lactate, body mass index, VO2max, mean training regimen and the hematological parameters significantly associated with running performance in univariate analysis were entered as independent variables, only MPV values before and after the trial remained significantly associated with running time. After adjustment for platelet count, the MPV value before the run (p = 0.042, but not thereafter (p = 0.247, remained significantly associated with running

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.

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

Gender differences in sport injury risk and types of inju-ries: a retrospective twelve-month study on cross-country skiers, swimmers, long-distance runners and soccer players.

Science.gov (United States)

Ristolainen, Leena; Heinonen, Ari; Waller, Benjamin; Kujala, Urho M; Kettunen, Jyrki A

2009-01-01

This twelve months survey compared injury risk and injury types by genders (312 females, 262 males) in 15- to 35-year-old cross-country skiers, swimmers, long- distance runners and soccer players. More male than female athletes reported at least one acute injury (44% vs. 35%, p gender differences in either of these comparisons. After adjustment for sport event males were at increased risk for posterior thigh overuse injuries compared to females (relative risk (RR) 5.8, 95% confidence interval (CI) 1.3 to 26.4, p difference between the sexes in overuse injury to the ankle persisted (female 0.11 vs. male 0.02 injuries/1000 exposure hours, p difference was found in such injuries when calculated per 1000 exposure hours. In conclusion, we found some gender differences in sport-related injuries, but most of these differences seemed to be explained at least in part by differences in the amount of training. Key pointsOnly a few sport injury studies have compared in-jury rates between the sexesOverall gender-related risk for acute and overuse injuries in top-level athletes between the sexes was smallSome gender differences in the specific anatomical locations of injuries as well as in specific injuries in sports were foundSome of these differences seem to be explained by the differences in the amount of training.

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

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.

Risk factors and most common traumatic injuries in people who practice long-distance running

Directory of Open Access Journals (Sweden)

Anna Lewandowska

2017-08-01

Full Text Available Undoubtedly, the fashion of running comes. Initially people used to run for fun, pleasure, to forget about worries or problems. With time, however, was no longer just about the idea itself, people more and more fascinated with jogging went one step further. At the same time, not realizing how important changes may occur in their body. These are usually overload or inflammatory changes. The aim of this paper is to present the most frequent injuries of long distance runners and the main predisposing factors for their trauma. The work will also cover the possibility of prevention of these injuries. The most important factors predisposing to injury include: the awareness of running people, the overweight and obesity, the incorrect running pattern and the inappropriate training plan. The consequences of these factors may be: runner's knee, leg overload syndrome, Achilles tendonitis, plantar fasciitis, fatigue fractures, and iliotibial-band syndrome. The injuries are, unfortunately, inscribed into the life of every runner, regardless of the level of advancement. However, it is worth remembering that they can be effectively prevented, and at the moment of their appearance, effectively heal. The injuries of runners depend primarily on their approach to practicing this form of physical activity, to a lesser extent from genetic or mechanical factors.

Effects of Low Versus Moderate Glycemic Index Diets on Aerobic Capacity in Endurance Runners: Three-Week Randomized Controlled Crossover Trial

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Krzysztof Durkalec-Michalski

2018-03-01

Full Text Available The glycemic index (GI of ingested carbohydrates may influence substrate oxidation during exercise and athletic performance. Therefore, the aim of this study was to assess the effect of low- and moderate-GI three-week diets on aerobic capacity and endurance performance in runners. We conducted a randomized crossover feeding study of matched diets differing only in GI (low vs. moderate in 21 endurance-trained runners. Each participant consumed both, low- (LGI and moderate-GI (MGI high-carbohydrate (~60% and nutrient-balanced diets for three weeks each. At the beginning and end of each diet, participants had their aerobic capacity and body composition measured and performed a 12-min running test. After LGI, time to exhaustion during incremental cycling test (ICT and distance covered in the 12-min run were significantly increased. The MGI diet led to an increase in maximal oxygen uptake ( V ˙ O2max, but no performance benefits were found after the MGI diet. The LGI and MGI diets improved time and workload at gas exchange threshold (GET during ICT. The results indicate that a three-week high-carbohydrate LGI diet resulted in a small but significant improvement in athletic performance in endurance runners. Observed increase in V ˙ O2max on MGI diet did not affect performance.

Distance Training in the European Union. ZIFF Papiere 96.

Science.gov (United States)

Keegan, Desmond

A study examined distance training in the European Union (EU) countries. First, recent literature on the following topics was reviewed: technology-supported learning, flexible and distance learning, development of open distance learning, and teleconferencing and distance learning. Next, enrollments and trends in distance learning in the EU as a…

Excessive Progression in Weekly Running Distance and Risk of Running-related Injuries

DEFF Research Database (Denmark)

Nielsen, R.O.; Parner, Erik Thorlund; Nohr, Ellen Aagaard

2014-01-01

Study Design An explorative, 1-year prospective cohort study. Objective To examine whether an association between a sudden change in weekly running distance and running-related injury varies according to injury type. Background It is widely accepted that a sudden increase in running distance...... is strongly related to injury in runners. But the scientific knowledge supporting this assumption is limited. Methods A volunteer sample of 874 healthy novice runners who started a self-structured running regimen were provided a global-positioning-system watch. After each running session during the study...... period, participants were categorized into 1 of the following exposure groups, based on the progression of their weekly running distance: less than 10% or regression, 10% to 30%, or more than 30%. The primary outcome was running-related injury. Results A total of 202 runners sustained a running...

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.

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...

Long-distance running, bone density, and osteoarthritis

International Nuclear Information System (INIS)

Lane, N.E.; Bloch, D.A.; Jones, H.H.; Marshall, W.H. Jr.; Wood, P.D.; Fries, J.F.

1986-01-01

Forty-one long-distance runners aged 50 to 72 years were compared with 41 matched community controls to examine associations of repetitive, long-term physical impact (running) with osteoarthritis and osteoporosis. Roentgenograms of hands, lateral lumbar spine, and knees were assessed without knowledge of running status. A computed tomographic scan of the first lumbar vertebra was performed to quantitate bone mineral content. Runners, both male and female, have approximately 40% more bone mineral than matched controls. Female runners, but not male runners, appear to have somewhat more sclerosis and spur formation in spine and weight-bearing knee x-ray films, but not in hand x-ray films. There were no differences between groups in joint space narrowing, crepitation, joint stability, or symptomatic osteoarthritis. Running is associated with increased bone mineral but not, in this cross-sectional study, with clinical osteoarthritis

Distance Learning for Teacher Training in Brazil

Directory of Open Access Journals (Sweden)

Alvana Maria Bof

2004-04-01

Full Text Available Proformação is a distance teacher certification course aimed at providing training to 27,000 uncertified teachers in 15 Brazilian states. This innovative program organizes human and technical resources for delivering distance education in a cost-effective manner. Different from other institutional systems – which typically employ their own dedicated content, design, and instructional resource personnel, and accompanied by a large pool of administrative staff – Proformação leverages pre-existing learning resources such as content experts, technology specialists, instruction, and student support systems from several institutions. Proformação goal is to create a viable teacher certification course to upgrade thousands of non-certified teachers working in the field. Proformação is coordinated by an administrative unit of the Brazilian Ministry of Education. To support the program, an information system was implemented to continuously and consistently monitor the program’s activities and results. Results of an external evaluation have been positive; Proformação is regarded by some as an innovative model for delivering decentralized training opportunities to large student numbers. Therefore, the findings in this article may prove interesting to those charged with implementing distance learning initiatives in developing countries, in that the lessons learned in Brazil may help others interested in implementing similar distance training programs.

Comparisons of Perceived Training Doses in Champion Collegiate-Level Male and Female Cross-country Runners and Coaches over the Course of a Competitive Season.

Science.gov (United States)

Barnes, Kyle R

2017-10-17

Session rating of perceived exertion (sRPE) is a practical tool for coaches to assess internal training load of their athletes. In a sport like cross-country running, that is individual in nature, but has a team training and competition component, information about the association between external and internal load is lacking. Furthermore, there is a need for studies that examine perception of training doses across multiple training cycles including the competitive season as well as between male and female athletes. Session RPE, duration, and training load (TL RPE  = sRPE × duration) of 25 highly trained male and female cross-country runners and their coaches were recorded for every training session (110 days) throughout a collegiate cross-country season. Intensity (sRPE), duration, and TL RPE were compared between coaches and runners by gender separately. Training sessions were also analyzed by those intended by the coaches to be easy, moderate, and hard as well as by training period. Data from 3024 training sessions were collected, 62% of which were considered "easy," 18% "moderate," and 20% "hard." Men and women rated coach-intended easy sessions significantly harder during each month of the season (effect size (ES) > 2.9, p sessions significantly higher than coaches (ES ≥ 1.0, p ≤ 0.002), whereas females rated hard intensity sessions significantly lower than coaches (ES > 0.5, p sessions (ES  0.05) or females and coach's moderate sessions (ES  0.05). Training intensity and TL RPE tended to increase throughout the season (p > 0.05), with a significant increase in moderate and hard intensity sessions in the last training period (p training throughout the cross-country season. Given the success of the athletes in this study, these results show how a simple system for monitoring training such as the sRPE method may improve control of training variables and provide a useful tool for coaches to evaluate training load placed on

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.

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.

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.

Six Weeks Habituation of Simulated Barefoot Running Induces Neuromuscular Adaptations and Changes in Foot Strike Patterns in Female Runners

Science.gov (United States)

Khowailed, Iman Akef; Petrofsky, Jerrold; Lohman, Everett; Daher, Noha

2015-01-01

Background The aim of this study was to examine the effects of a 6-week training program of simulated barefoot running (SBR) on running kinetics in habitually shod (wearing shoes) female recreational runners. Material/Methods Twelve female runners age 25.7±3.4 years gradually increased running distance in Vibram FiveFingers minimal shoes over a 6-week period. The kinetic analysis of treadmill running at 10 Km/h was performed pre- and post-intervention in shod running, non-habituated SBR, and habituated SBR conditions. Spatiotemporal parameters, ground reaction force components, and electromyography (EMG) were measured in all conditions. Results Post-intervention data indicated a significant decrease across time in the habituation SBR for EMG activity of the tibialis anterior (TA) in the pre-activation and absorptive phase of running (Prunning, unhabituated SBR, and habituated SBR. Six weeks of SBR was associated with a significant decrease in the loading rates and impact forces. Additionally, SBR significantly decrease the stride length, step duration, and flight time, and stride frequency was significantly higher compared to shod running. Conclusions The findings of this study indicate that changes in motor patterns in previously habitually shod runners are possible and can be accomplished within 6 weeks. Non-habituation SBR did not show a significant neuromuscular adaptation in the EMG activity of TA and GAS as manifested after 6 weeks of habituated SBR. PMID:26166443

Distance exercised during submaximal training on race winnings for Thoroughbred racehorses

Directory of Open Access Journals (Sweden)

Carolina Berkman

2015-07-01

Full Text Available Evaluations of the physical fitness of Thoroughbred racehorses have been correlated with race earnings, but few reports exist about the influence of the distance exercised during training on both physical conditioning indices and financial productivity. During one training season sixteen claiming Thoroughbred horses were subjected to submaximal training and monitored by a global positioning system (GPS coupled to a heart rate monitor. After initial and single monitoring, the horses were distributed into two groups of eight individuals each; one group exercised short distances (SD between 1600 and 1900m, while the other exercised long distances (LD between 2000 and 2350m. The duration (min and mean and maximal velocities (ms-1attained during each session were determined, as well as the difference in distances exercised (m between official races and each training session. Blood lactate concentration ([LA] during recovery was also determined. Student's t-test was used for a non-paired analysis, with P≤0.05 considered significant. The winnings (USD of each horse were correlated with the peak heart rate (HRpeak attained during the training session. The distances exercised in the training sessions were greater in relation to the official races distances by 24.7% and 40% for SD and LD, respectively. Lactatemia did not differ between the groups. The HRpeak obtained during the training session was lower in LD group. The velocity at which the heart rate reached 200 bpm (V200 was higher in LD group. There was a moderate correlation (r= 0.42 between the highest winnings and lowest HRpeak. The horses that ran longer distances during their submaximal training session had better cardiac conditioning and tendency to increase financial productivity

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

Case Study: Body Composition Periodization in an Olympic-Level Female Middle-Distance Runner Over a 9-Year Career.

Science.gov (United States)

Stellingwerff, Trent

2018-05-25

This case study features an Olympic-level female middle-distance runner implementing a science-based approach to body composition periodization. Data are emerging to suggest that it is not sustainable from a health and/or performance perspective to be at peak body composition year-round, so body composition needs to be strategically periodized. Anthropometric (n = 44), hematological, other health measures, and 1,500-m race performances (n = 83) were periodically assessed throughout a 9-year career. General preparation phase (September to April) featured the athlete at ∼2-4% over ideal competition phase body weight (BW) and body fat (%), with optimal energy availability being prioritized. The competition body composition optimization phase (May to August) included creating an individualized time frame and caloric deficit with various feedback metrics (BW, performance, and hunger) to guide the process. There were significant seasonal fluctuations in anthropometric outcomes between phases (47.3 ± 0.8 vs. 48.3 ± 0.9 kg BW; 53.6 ± 7.8 vs. 61.6 ± 9.7 mm International Society for the Advancement of Kinanthropometry sum of 8 [So8] skinfolds; p career (r = -.838; p = .018). The range of body composition during the competition period was 46.0-48.0 kg BW and a So8 range was 42.0-55.9 mm. There were also significant positive correlations between slower 1,500-m race times and increasing So8 (r = .437; p career injuries. This case study demonstrates a body composition periodization approach that allowed for targeted peak yearly performances, which improved throughout her career, while maximizing training adaptation and long-term athlete health through optimal energy availability.

Ground reaction forces and kinematics in distance running in older-aged men

NARCIS (Netherlands)

Bus, Sicco A.

2003-01-01

Purpose: The biomechanics of distance running has not been studied before in older-aged runners but may be different than in younger-aged runners because of musculoskeletal degeneration at older age. This study aimed at determining whether the stance phase kinematics and ground reaction forces in

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.

Excessive progression in weekly running distance and risk of running-related injuries: an association which varies according to type of injury.

Science.gov (United States)

Nielsen, Rasmus Østergaard; Parner, Erik Thorlund; Nohr, Ellen Aagaard; Sørensen, Henrik; Lind, Martin; Rasmussen, Sten

2014-10-01

An explorative, 1-year prospective cohort study. Objective To examine whether an association between a sudden change in weekly running distance and running-related injury varies according to injury type. It is widely accepted that a sudden increase in running distance is strongly related to injury in runners. But the scientific knowledge supporting this assumption is limited. A volunteer sample of 874 healthy novice runners who started a self-structured running regimen were provided a global-positioning-system watch. After each running session during the study period, participants were categorized into 1 of the following exposure groups, based on the progression of their weekly running distance: less than 10% or regression, 10% to 30%, or more than 30%. The primary outcome was running-related injury. A total of 202 runners sustained a running-related injury. Using Cox regression analysis, no statistically significant differences in injury rates were found across the 3 exposure groups. An increased rate of distance-related injuries (patellofemoral pain, iliotibial band syndrome, medial tibial stress syndrome, gluteus medius injury, greater trochanteric bursitis, injury to the tensor fascia latae, and patellar tendinopathy) existed in those who progressed their weekly running distance by more than 30% compared with those who progressed less than 10% (hazard ratio = 1.59; 95% confidence interval: 0.96, 2.66; P = .07). Novice runners who progressed their running distance by more than 30% over a 2-week period seem to be more vulnerable to distance-related injuries than runners who increase their running distance by less than 10%. Owing to the exploratory nature of the present study, randomized controlled trials are needed to verify these results, and more experimental studies are needed to validate the assumptions. Still, novice runners may be well advised to progress their weekly distances by less than 30% per week over a 2-week period.

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

Training-Load Distribution in Endurance Runners: Objective Versus Subjective Assessment.

Science.gov (United States)

Manzi, Vincenzo; Bovenzi, Antonio; Castagna, Carlo; Sinibaldi Salimei, Paola; Volterrani, Maurizio; Iellamo, Ferdinando

2015-11-01

To assess the distribution of exercise intensity in long-distance recreational athletes (LDRs) preparing for a marathon and to test the hypothesis that individual perception of effort could provide training responses similar to those provided by standardized training methodologies. Seven LDRs (age 36.5 ± 3.8 y) were followed during a 5-mo training period culminating with a city marathon. Heart rate at 2.0 and 4.0 mmol/L and maximal heart rate were used to establish 3 intensity training zones. Internal training load (TL) was assessed by training zones and TRIMPi methods. These were compared with the session-rating-of-perceived-exertion (RPE) method. Total time spent in zone 1 was higher than in zones 2 and 3 (76.3% ± 6.4%, 17.3% ± 5.8%, and 6.3% ± 0.9%, respectively; P = .000 for both, ES = 0.98, ES = 0.99). TL quantified by session-RPE provided the same result. The comparison between session-RPE and training-zones-based methods showed no significant difference at the lowest intensity (P = .07, ES = 0.25). A significant correlation was observed between TL RPE and TL TRIMPi at both individual and group levels (r = .79, P marathon (r = -.83, P recreational LDRs most of the training time is spent at low intensity and that this is associated with improved performances. Session-RPE is an easy-to-use training method that provides responses similar to those obtained with standardized training methodologies.

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.

Effect of maximal oxygen uptake and different forms of physical training on serum lipoproteins.

Science.gov (United States)

Schnabel, A; Kindermann, W

1982-01-01

260 well trained male sportsmen between 17 and 30 years of age participating in a variety of events were examined for total serum cholesterol and lipoprotein cholesterol and compared with 37 moderately active leisure-time sportsmen and 20 sedentary controls of similar ages and sex. Lipoprotein cholesterol distribution was determined by quantitative electrophoresis. Mean HDL-cholesterol increased progressively from the mean of the sedentary control to the mean of the long-distance runners, indicating a graded effect of physical activity on HDL-cholesterol. In all sporting groups mean LDL-cholesterol tended to be lower than in the controls, no association between LDL-cholesterol and form of training being apparent. Except for the long-distance runners, all sporting groups tended to be lower in total cholesterol than the controls. The HDL-/total cholesterol and LDL/HDL ratios yielded a better discrimination between the physically active and inactive than the HDL-cholesterol alone. Significant positive correlations with maximal oxygen uptake and roentgenologically determined heart volume were found for HDL-cholesterol and HDL-/total cholesterol, and negative ones for LDL/HDL. Differences in the regressions among subsets made up of sporting groups under different physical demands suggest a positive relationship between lipoprotein distribution and the magnitude of the trained muscle mass.

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.

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 ...

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.

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.

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.

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

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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.

GENETIC IDENTIFICATION FOR TUNA AND RAINBOW RUNNER CAPTURE IN NORTH BALI WATERS

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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.

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.

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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.

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

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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

Fat intake and injury in female runners.

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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.

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

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

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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.

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

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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

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

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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

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.

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.

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.

Distance Education and Corporate Training in Brazil: Regulations and interrelationships

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Stella C. S. Porto

2008-06-01

Full Text Available Distance education in Brazil has evolved more slowly than distance education offerings in other developing countries. This is because all aspects of Brazil’s publicly-funded educational system are excessively regulated, highly bureaucratic, and tightly centralized. Such highly centralized bureaucracy and strict control has resulted in tremendous hurdles that work to thwart the adoption, provision, and diffusion of distance education. This is not good news: Like many developing countries, Brazil is also characterized by wide gaps in wealth distribution, with 20 percent of its population functionally illiterate and living below the poverty line. Distance education, therefore, could be used to help train Brazil’s citizens. Brazil’s emerging status in the global economy, however, is generating enormous opportunities that are fueling demand for change. For example, in their quest to be competitive in the emerging global economy, Brazil’s corporate sector has addressed this challenge by establishing corporate universities to train and educate their employees; much of this corporate training and education takes place online and at a distance. The established and emerging educational opportunities provided by Brazil’s corporate sector, in turn, is fuelling the demand for the provision of distance education throughout Brazil. Indeed, most Brazilians are ready for distance education. Many Brazilian households own television sets and cellular telephones, and its expanding communication infrastructure has capacity to support distance and continuing education models. Moreover, this capacity is currently being used by Brazil’s rapidly expanding corporate university sector. In spite of Brazil’s emergence in the global marketplace and its private-sector educational success stories, Brazil’s public educational institutions have not kept pace. This is due to Brazil’s long-standing stringent regulation of its public education sector. Recent

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 ( ...

Age-Predicted Maximal Heart Rate in Recreational Marathon Runners: A Cross-Sectional Study on Fox's and Tanaka's Equations

Science.gov (United States)

Nikolaidis, Pantelis T.; Rosemann, Thomas; Knechtle, Beat

2018-01-01

Age-based prediction equations of maximal heart rate (HRmax), such as the popular formulas Fox's 220-age, or Tanaka's 208-0.7 × age, have been widely used in various populations. Surprisingly, so far these equations have not been validated in marathon runners, despite the importance of the role of HRmax for training purposes in endurance running. The aim of the present study was to examine the validity of Fox and Tanaka equations in a large sample of women and men recreational marathon runners. Participants (n = 180, age 43.2 ± 8.5 years, VO2max 46.8 mL/min/kg, finishers in at least one marathon during the last year) performed a graded exercise test on a treadmill, where HRmax was measured. Measured HRmax correlated largely with age in the total sample (r = −0.50, p marathon runners. In addition, exercise physiologists and sport scientists should consider the observed differences among various assessment methods when performing exercise testing or prescribing training program relying on HR. PMID:29599724

Age-Predicted Maximal Heart Rate in Recreational Marathon Runners: A Cross-Sectional Study on Fox's and Tanaka's Equations.

Science.gov (United States)

Nikolaidis, Pantelis T; Rosemann, Thomas; Knechtle, Beat

2018-01-01

Age-based prediction equations of maximal heart rate (HR max ), such as the popular formulas Fox's 220-age, or Tanaka's 208-0.7 × age, have been widely used in various populations. Surprisingly, so far these equations have not been validated in marathon runners, despite the importance of the role of HR max for training purposes in endurance running. The aim of the present study was to examine the validity of Fox and Tanaka equations in a large sample of women and men recreational marathon runners. Participants ( n = 180, age 43.2 ± 8.5 years, VO 2max 46.8 mL/min/kg, finishers in at least one marathon during the last year) performed a graded exercise test on a treadmill, where HR max was measured. Measured HR max correlated largely with age in the total sample ( r = -0.50, p marathon runners. In addition, exercise physiologists and sport scientists should consider the observed differences among various assessment methods when performing exercise testing or prescribing training program relying on HR.

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.

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

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.

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.

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.

The Influence of runner system on production of injection molds

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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

Mucosal immunity and upper respiratory tract symptoms in recreational endurance runners.

Science.gov (United States)

Ihalainen, Johanna K; Schumann, Moritz; Häkkinen, Keijo; Mero, Antti A

2016-01-01

The present study investigated the effects of a 12-week endurance-training intervention on salivary proteins and upper respiratory tract symptoms (URS) in 25 young men. Saliva samples of 25 recreational male endurance runners (age 34.6 years, body mass index = 23.8 kg·m(-2), peak aerobic capacity = 47.2 mL·kg(-1)·min(-1)) were collected before (PRE) and after (POST) the training intervention, in a fasting state, as well as both before and after a maximal incremental treadmill run. The training consisted of both continuous and interval training sessions, 4-6 times per week based on the polarized training approach. Participants filled in Wisconsin Upper Respiratory Symptom Survey-21 and were retrospectively divided into 2 groups according to whether they reported URS (URS group, n = 13) or not (HEALTHY group, n = 12). Basal salivary immunoglobulin A (sa-sIgA) levels were significantly higher (+70%, p < 0.05) in the HEALTHY group both at PRE and POST whereas no significant differences were observed in salivary immunoglobulin M, salivary immunoglobulin G, lysozyme, or salivary α-amylase activity (sAA). Sa-sIgA concentration at PRE significantly correlated with the number of sick-days (R = -0.755, p < 0.001) in all subjects. The incremental treadmill run acutely increased sAA significantly (p < 0.05) at PRE (200%) and POST (166%) in the HEALTHY group but not in the URS group. This study demonstrated that subjects, who experienced URS during the 12 weeks of progressive endurance training intervention, had significantly lower basal sa-sIgA levels both before and after the experimental endurance training period. In addition to sa-sIgA, acute sAA response to exercise might be a possible determinant of susceptibility to URS in endurance runners.

Changes in Foot Shape after Long-Distance Running

OpenAIRE

Fukano, Mako; Iso, Shigeo

2015-01-01

Changes in foot shape during long-distance running may lead to alteration in shoe fit. However, little information is available on changes in foot shape following long-distance running. The purpose of this study was to assess changes in foot shape in experienced runners after a single long-distance run. Data from the right feet of 21 subjects were obtained using a foot scanner before and after running 35 km on an asphalt road. After the run, the dorsal height, navicular height, and arch heigh...

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.

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

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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

Mechanisms of adaptation to intensive loads of 400 meters’ hurdles runners at stage of initial basic training

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A.S. Rovniy

2015-08-01

Full Text Available Purpose: is study of adaptation mechanisms of 400 meter’ hurdles-runners to intensive physical loads. Material: in the research 13 - 400 meters’ hurdles-runners and 13 - 400 meters’ runners participated. Results: it was found that physiological cost of sportsmen’s special workability has fragmentary character. We presented results of physiological and bio-chemical adaptation mechanisms to dozed work. The received results have no confident distinctions and can not objectively characterize mechanisms of sportsmen’s special workability. We did not detect definite differences in indicators of mechanisms, ensuring sportsmen’s special workability under dozed loads. We found, that level of anaerobic glycolysis is an objective criterion of 400 meter’ hurdles-runners’ special workability. It was shown that for determination of functional potentials for such kind of functioning it is necessary to apply special loads. Conclusions: the received results deepen information about mechanisms of adaptation to specific competition functioning. Correct approaches to processing and analysis of the research’s results permit to more specifically determine sportsmen’s functional potentials in different kinds of competition functioning.

Muscle metabolism of professional athletes using 31P-spectroscopy

International Nuclear Information System (INIS)

Maeurer, J.; Soellner, O.; Ehrenstein, T.; Knollmann, F.; Vogl, T.J.; Felix, R.; Konstanczak, P.; Wolff, R.

1999-01-01

Purpose: The aim of the study was to examine muscle metabolism in athletes by 31 P-spectroscopy (MRS) and to evaluate to what degree the respective resonance spectrum correlates with the kind of muscle exercise. Material and Methods: Twelve runners and 12 young ice skaters were studied by 31 P-spectroscopy of the gastrocnemic medialis muscle and the vastus medialis muscle using a surface coil at 1.5 T. Results: Sprinters displayed a higher phosphocreatinine/inorganic phosphate (PCr/Pi) and PCr/β-ATP ratios than marathon runners. The respective parameters for middle distance runners were in between. Ice skaters could prospectively be divided into sprint- and long-distance runners by our results which correlated with the athletes' training performance. Conclusion: 31 P-spectroscopy can evaluate the distribution of muscle fiber types. Thus, the athlete's potential for sprint- or long-distance running can be determined. Additional studies will have to demonstrate to what extent training may change muscle fiber distribution. (orig.)

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

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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

Effects of a 4-week high-intensity interval training on pacing during 5-km running trial

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R. Silva

2017-10-01

Full Text Available This study analyzed the influence of a 4-week high-intensity interval training on the pacing strategy adopted by runners during a 5-km running trial. Sixteen male recreational long-distance runners were randomly assigned to a control group (CON, n=8 or a high-intensity interval training group (HIIT, n=8. The HIIT group performed high-intensity interval-training twice per week, while the CON group maintained their regular training program. Before and after the training period, the runners performed an incremental exercise test to exhaustion to measure the onset of blood lactate accumulation, maximal oxygen uptake (VO2max, and peak treadmill speed (PTS. A submaximal constant-speed test to measure the running economy (RE and a 5-km running trial on an outdoor track to establish pacing strategy and performance were also done. During the 5-km running trial, the rating of perceived exertion (RPE and time to cover the 5-km trial (T5 were registered. After the training period, there were significant improvements in the HIIT group of ∼7 and 5% for RE (P=0.012 and PTS (P=0.019, respectively. There was no significant difference between the groups for VO2max (P=0.495 or onset of blood lactate accumulation (P=0.101. No difference was found in the parameters measured during the 5-km trial before the training period between HIIT and CON (P>0.05. These findings suggest that 4 weeks of HIIT can improve some traditional physiological variables related to endurance performance (RE and PTS, but it does not alter the perception of effort, pacing strategy, or overall performance during a 5-km running trial.

Rearfoot striking runners are more economical than midfoot strikers.

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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.

Vulnerability to exercise addiction, socio-demographic, behavioral and psychological characteristics of runners at risk for eating disorders.

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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.

Outrunning major weight gain: a prospective study of 8,340consistent runners during 7 years of follow-up

Energy Technology Data Exchange (ETDEWEB)

Williams, Paul T.

2006-01-06

Background: Body weight increases with aging. Short-term,longitudinal exercise training studies suggest that increasing exerciseproduces acute weight loss, but it is not clear if the maintenance oflong-term, vigorous exercise attenuates age-related weight gain inproportion to the exercise dose. Methods: Prospective study of 6,119 maleand 2,221 female runners whose running distance changed less than 5 km/wkbetween their baseline and follow-up survey 7 years later. Results: Onaverage, men who ran modest (0-24 km/wk), intermediate (24-48 km/wk) orprolonged distances (>_48 km/wk) all gained weight throughage 64,however, those who ran ?48 km/wk had one-half the average annual weightgain of those who ran<24 km/wk. Age-related weight gain, and itsreduction by running, were both greater in younger than older men. Incontrast, men s gain in waist circumference with age, and its reductionby running, were the same in older and younger men. Women increased theirbody weight and waist and hip circumferences over time, regardless ofage, which was also reduced in proportion to running distance. In bothsexes, running did not attenuate weight gain uniformly, but ratherdisproportionately prevented more extreme increases. Conclusion: Men andwomen who remain vigorously active gain less weight as they age and thereduction is in proportion to the exercise dose.

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

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.

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.

Strength Training for Middle- and Long-Distance Performance: A Meta-Analysis.

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Berryman, Nicolas; Mujika, Inigo; Arvisais, Denis; Roubeix, Marie; Binet, Carl; Bosquet, Laurent

2018-01-01

To assess the net effects of strength training on middle- and long-distance performance through a meta-analysis of the available literature. Three databases were searched, from which 28 of 554 potential studies met all inclusion criteria. Standardized mean differences (SMDs) were calculated and weighted by the inverse of variance to calculate an overall effect and its 95% confidence interval (CI). Subgroup analyses were conducted to determine whether the strength-training intensity, duration, and frequency and population performance level, age, sex, and sport were outcomes that might influence the magnitude of the effect. The implementation of a strength-training mesocycle in running, cycling, cross-country skiing, and swimming was associated with moderate improvements in middle- and long-distance performance (net SMD [95%CI] = 0.52 [0.33-0.70]). These results were associated with improvements in the energy cost of locomotion (0.65 [0.32-0.98]), maximal force (0.99 [0.80-1.18]), and maximal power (0.50 [0.34-0.67]). Maximal-force training led to greater improvements than other intensities. Subgroup analyses also revealed that beneficial effects on performance were consistent irrespective of the athletes' level. Taken together, these results provide a framework that supports the implementation of strength training in addition to traditional sport-specific training to improve middle- and long-distance performance, mainly through improvements in the energy cost of locomotion, maximal power, and maximal strength.

Estimated VO2max and its corresponding velocity predict performance of amateur runners

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Bruno Ribeiro Ramalho Oliveira

2012-03-01

Full Text Available In recent years, there has been a substantial increase in the number of runners, with a proportional increase in their involvement in amateur street competition. Identification of the determinants of performance in this population appears necessary for optimization of time devoted to training. The objective of this study was to ascertain the association between estimated maximal oxygen uptake (VO2max, critical velocity (CV and VO2max velocity (VVO2max and athletic performance in the 3.6 km (uphill and 10 and 21.1 km (flatland events. Twelve amateur runners (nine male, mean age 36 ± 5 years underwent five tests: 1 and 5 km race on level ground, 3.6 km race with slope (≈8%, and indirect VO2max measurement. CV was determined from the linear relationship between distance and run time on the first two tests. The subjects then took part in two official 10 km and 21.1 km (half marathon races. VVO2max was calculated from the VO2max through a metabolic equation. VO2max showed the best association with running performance in the 10 and 21.1 km events. For the uphill race, VVO2max showed a better association. Overall, the variable with the highest average association was VO2max (0.91±0.07, followed by VVO2max (0.90±0.04 and VC (0.87±0.06. This study showed strong associations between physiological variables established by low-cost, user-friendly indirect methods and running performance in the 10 and 21.1 km (flatland and 3.6 km (uphill running events.

The effect of plyometric training on power and kicking distance in female adolescent soccer players.

Science.gov (United States)

Rubley, Mack D; Haase, Amaris C; Holcomb, William R; Girouard, Tedd J; Tandy, Richard D

2011-01-01

The purpose of this study was to measure the effects of low-frequency, low-impact plyometric training on vertical jump (VJ) and kicking distance in female adolescent soccer players. Sixteen adolescent soccer players were studied (age 13.4 ± 0.5 years) across 14 weeks. The control group (general soccer training only) had 6 subjects, and the plyometric training (general soccer training plus plyometric exercise) group had 10 subjects. All subjects were tested for VJ and kicking distance on 3 occasions: pre-test, 7 weeks, and 14 weeks. Data were analyzed using a 2 (Training) × 3 (Test) analysis of variance (ANOVA) with repeated measures on the factor test. No significant difference in kicking distance was found between groups at pre-test (p = 0.688) or 7 weeks (p = 0.117). The plyometric group had significantly greater kicking distance after 14 weeks (p plyometric group had a significantly higher VJ after 14 weeks (p = 0.014). These results provide strength coaches with a safe and effective alternative to high-intensity plyometric training. Based on these findings, to increase lower-body power resulting in increased VJ and kicking distance, strength coaches should implement once-weekly, low-impact plyometric training programs with their adolescent athletes.

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...

Prevalence, Severity and Potential Nutritional Causes of Gastrointestinal Symptoms during a Marathon in Recreational Runners

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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.

Stress reactivity to and recovery from a standardised exercise bout: a study of 31 runners practising relaxation techniques.

Science.gov (United States)

Solberg, E E; Ingjer, F; Holen, A; Sundgot-Borgen, J; Nilsson, S; Holme, I

2000-08-01

To compare the efficacy in runners of two relaxation techniques with regard to exercise reactivity and recovery after exercise. Thirty one adult male runners were studied prospectively for six months in three groups practising either meditation (n = 11) or autogenic training (n = 11) or serving as controls (n = 10). Before and after the six months relaxation intervention, indicators of reactivity to exercise and metabolism after exercise (blood lactate concentration, heart rate (HR), and oxygen consumption (VO2)), were tested immediately after and 10 minutes after exercise. Resting HR was also assessed weekly at home during the trial. State anxiety was measured before and after the intervention. After the relaxation training, blood lactate concentration after exercise was significantly (pmeditation group compared with the control group. No difference was observed in lactate responses between the autogenic training group and the control group. There were no significant differences among the groups with regard to HR, VO2, or levels of anxiety. Meditation training may reduce the lactate response to a standardised exercise bout.

Exercise training in transgenic mice is associated with attenuation of early breast cancer growth in a dose-dependent manner.

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Jorming Goh

Full Text Available Epidemiological research suggests that regular physical activity confers beneficial effects that mediate an anti-tumor response and may reduce cancer recurrence. It is unclear what amount of physical activity is necessary to exert such a protective effect and what mechanisms are involved. We investigated the effects of voluntary wheel running on tumor progression and cytokine gene expression in the transgenic polyoma middle T oncoprotein (PyMT mouse model of invasive breast cancer. Runners showed significantly reduced tumor sizes compared with non-runners after 3 weeks of running (p ≤ 0.01, and the greater the running distance the smaller the tumor size (Pearson's r = -0.61, p ≤ 0.04, R(2 = 0.38. Mice running greater than 150 km per week had a significantly attenuated tumor size compared with non-runners (p ≤ 0.05. Adipose tissue mass was inversely correlated with tumor size in runners (Pearson's r = -0.77, p = 0.014 but not non-runners. Gene expression of CCL22, a cytokine associated with recruitment of immunosuppressive T regulatory cells, was decreased in tumors of runners compared to non-runners (p ≤ 0.005. No differences in tumor burden or metastatic burden were observed between runners and non-runners after ten weeks of running when the study was completed. We conclude that voluntary wheel running in PyMT mice correlates with an attenuation in tumor progression early during the course of invasive breast cancer. This effect is absent in the later stages of overwhelming tumor burden even though cytokine signaling for immunosuppressive regulatory T cells was down regulated. These observations suggest that the initiation of moderate exercise training for adjunctive therapeutic benefit early in the course of invasive breast cancer should be considered for further investigation.

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.

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.

A chronotype comparison of South African and Dutch marathon runners: The role of scheduled race start times and effects on performance.

Science.gov (United States)

Henst, Rob H P; Jaspers, Richard T; Roden, Laura C; Rae, Dale E

2015-01-01

Recently, a high prevalence of morning-types was reported among trained South African endurance athletes. Proposed explanations for this observation were that either the chronotype of these athletes is better suited to coping with the early-morning start times of endurance events in South Africa; or habitual early waking for training or endurance events may have conditioned the athletes to adapt and become morning-types. The South African endurance athletes also had earlier chronotypes compared to a control population of less active individuals, suggesting that individuals who are more physically active may have earlier chronotypes. However, since both the South African athlete and control groups showed an overrepresentation of morning-types compared to European and American populations, the South African climate may in part have explained this bias towards morningness. Given the latitude and climate differences between South Africa and the Netherlands, and that South African marathons typically start at about 06:30 while those in the Netherlands start later (±11:00), comparison of South African and Dutch marathon runners and active controls would allow for simultaneous assessment of the effects of marathon start time, degree of physical activity and climate on chronotype. Therefore, the primary aims of this study were: (i) to assess the effect of marathon start time on chronotype in marathon runners and (ii) to determine the extent to which either degree of physical activity or climate might explain the bias towards morningness observed in South African athletes and controls. A secondary aim was to determine whether any relationships exist between chronotype, PERIOD3 (PER3) variable number tandem repeat (VNTR) polymorphism genotype, habitual training habits and marathon performance. Trained male marathon runners from South Africa (n = 95) and the Netherlands (n = 90), and active but non-competitive male controls from South Africa (n = 97) and the

The Effects of Backwards Running Training on Forward Running Economy in Trained Males.

Science.gov (United States)

Ordway, Jason D; Laubach, Lloyd L; Vanderburgh, Paul M; Jackson, Kurt J

2016-03-01

Backwards running (BR) results in greater cardiopulmonary response and muscle activity compared with forward running (FR). BR has traditionally been used in rehabilitation for disorders such as stroke and lower leg extremity injuries, as well as in short bursts during various athletic events. The aim of this study was to measure the effects of sustained backwards running training on forward running economy in trained male athletes. Eight highly trained, male runners (26.13 ± 6.11 years, 174.7 ± 6.4 cm, 68.4 ± 9.24 kg, 8.61 ± 3.21% body fat, 71.40 ± 7.31 ml·kg(-1)·min(-1)) trained with BR while harnessed on a treadmill at 161 m·min(-1) for 5 weeks following a 5-week BR run-in period at a lower speed (134 m·min(-1)). Subjects were tested at baseline, postfamiliarized, and post-BR training for body composition, a ramped VO2max test, and an economy test designed for trained male runners. Subjects improved forward running economy by 2.54% (1.19 ± 1.26 ml·kg(-1)·min(-1), p = 0.032) at 215 m·min(-1). VO2max, body mass, lean mass, fat mass, and % body fat did not change (p > 0.05). Five weeks of BR training improved FR economy in healthy, trained male runners without altering VO2max or body composition. The improvements observed in this study could be a beneficial form of training to an already economical population to improve running economy.

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.

[Physiological characteristics and the level of risk factors for ischemic heart disease in marathon runners between 30 and 59 years of age].

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Kostka, T; Drygas, W; Mrozek, P

1989-02-06

The results of anthropometric, biochemical, cardiological and performance capacity studies in the 37 marathon runners, 113 men systematically practising recreational training programme with a domination of endurance exercises and 44 healthy men with little leisure time physical activity have been compared. In comparison with a group of physically non-active persons, the marathon runners are characterized by considerably higher physical working capacity, slimmer figure, lower resting heart rate, lower diastolic blood pressure, high concentration of HDL cholesterol and lower cholesterol: HDL cholesterol index. However, these differences are minimal in comparison with other systematically training persons, and with regard to the majority of factors statistically insignificant. It seems that for reaching the physiological effects desired from the point of view of ischemic heart disease prevention the endurance training of lower capacity and intensity would be sufficient.

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

Joint stiffness and running economy during imposed forefoot strike before and after a long run in rearfoot strike runners.

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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.

KINEMATIC CHANGES DURING A MARATHON FOR FAST AND SLOW RUNNERS

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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

Prospective comparison of running injuries between shod and barefoot runners.

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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/

Prevalência de lesões em corredores de rua e fatores associados Prevalence of injuries and associated factors among street runners

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Adriano Akira Ferreira Hino

2009-02-01

Full Text Available O objetivo deste estudo foi analisar a prevalência de lesões esportivas e os fatores associados em corredores de rua por meio de um inquérito de morbidade referida. Os participantes foram selecionados por convite e por voluntariedade entre os corredores do Circuito de Ruas da Cidade de Curitiba-PR. Foram entrevistados 295 indivíduos (77,3% homens. As prevalências foram descritas de acordo com as variáveis de estudo e a regressão de Poisson foi utilizada para testar as associações (p The aim of this study was to analyze the prevalence of sports-related injuries and associated factors in street runners through a referred morbidity survey. Participants were selected by invitation and by volunteering among the runners from the Curitiba City Street Running Circuit during the months of September to November. 295 runners were interviewed (77.3% men. Prevalence rates were described accordingly to the study variables and Poisson regression was employed to test associations (p/ training more than 30min/day (31.3%; and men training more than 60 min/day (34.2%. None of the variables analyzed were associated with self-reported sport injuries. The majority of injured subjects (60.5% remained less than three months away from training and those with training volume between 31 and 60 min/day were more likely to show this condition (prevalence ratio/ =/ 2.44; CI95% = 0.99-6.06; p = 0.05. It is concluded that sports injuries prevalence is observed in 1/3 of men and 1/4 of women. The variables investigated were not associated with prevalence of sport injuries in street runners and the injuries severity is associated with training volume.

Excellent results for CERN runners

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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...

Digital control systems training on a distance learning platform

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Jan PIECHA

2009-01-01

Full Text Available The paper deals with new training technologies development based on approach to distance learning website, implemented in the laboratory of a Traffic Engineering study branch at Faculty of Transport. The discussed computing interface allows students complete knowledge of traffic controllers’ architecture and machine language programming fundamentals. These training facilities are available at home; at their remote terminal. The training resources consist of electronic / computer based training; guidebooks and software units. The laboratory provides the students with an interface entering into simulation packages and programming interfaces, supporting the web training facilities. The courseware complexity selection is one of the most difficult factors in intelligent training unit’s development. The dynamically configured application provides the user with his individually set structure of the training resources. The trainee controls the application structure and complexity, from the time he started. For simplifying the training process and studying activities, several unifications were provided. The introduced ideas need various standardisations, simplifying the e-learning units’ development and application control processes [8], [9]. Further training facilities development concerns virtual laboratory environment organisation in laboratories of Transport Faculty.

The Study of the Impacts of "Running" on the Contact Area of Soles and Maximal Strength among Elite Middle Distance Runners

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Uzun, Ahmet; Aydos, Latif; Kaya, Metin; Yuksel, Mehmet Fatih; Pekel, Haci Ahmet

2017-01-01

It is possible that running training for many years in athletics affects athletes' running patterns and sole structure. The main aim of this study is to examine the effect of maximal force applied to the floor area and contact area of the athletes with related to mid-distance training for athletics. 18 male athletes who represent Turkey on the…

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

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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.

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

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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.

Short-Term Absenteeism and Health Care Utilization Due to Lower Extremity Injuries Among Novice Runners: A Prospective Cohort Study.

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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.

Which spike train distance is most suitable for distinguishing rate and temporal coding?

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Satuvuori, Eero; Kreuz, Thomas

2018-04-01

It is commonly assumed in neuronal coding that repeated presentations of a stimulus to a coding neuron elicit similar responses. One common way to assess similarity are spike train distances. These can be divided into spike-resolved, such as the Victor-Purpura and the van Rossum distance, and time-resolved, e.g. the ISI-, the SPIKE- and the RI-SPIKE-distance. We use independent steady-rate Poisson processes as surrogates for spike trains with fixed rate and no timing information to address two basic questions: How does the sensitivity of the different spike train distances to temporal coding depend on the rates of the two processes and how do the distances deal with very low rates? Spike-resolved distances always contain rate information even for parameters indicating time coding. This is an issue for reasonably high rates but beneficial for very low rates. In contrast, the operational range for detecting time coding of time-resolved distances is superior at normal rates, but these measures produce artefacts at very low rates. The RI-SPIKE-distance is the only measure that is sensitive to timing information only. While our results on rate-dependent expectation values for the spike-resolved distances agree with Chicharro et al. (2011), we here go one step further and specifically investigate applicability for very low rates. The most appropriate measure depends on the rates of the data being analysed. Accordingly, we summarize our results in one table that allows an easy selection of the preferred measure for any kind of data. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Influence of yearlong training on the state of cardiovascular, autonomic nervous system and physical performance in female 400 meters runners

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Ye. L. Mikhalyuk

2016-04-01

Full Text Available Aim of the research – identification and comparison of heart rate variability, central hemodynamics and physical performance in 400 meters runners from the III category to masters of sports of international class (MSIC in the annual cycle of the training process. Materials and methods. The study included 22 female athletes, 400 meters runners between the ages of 14 and 27 years (mean age – 16.8 ± 0.67 years, running experience – from 2 to 13 years (average – 4.4 ± 0.68 years in the preparatory and competitive periods. Body length and weight of athletes were 167.9 ± 0.91 cm and 52.5 ± 0.98 kg, respectively. For the analysis of the autonomic regulation of cardiac activity mathematical methods of HRV analysis were used. Analysis and evaluation of periodic components of heart rate were carried out by means of the research of spectral parameters of autocorrelation functions. Determination of physical performance was carried out under the practical standard on the cycle ergometer. It was established that in high class sportswomen (n=12 and ones with qualifications of the II–III category (n=10 in the competitive period there were strengthening of parasympathetic effects of ANS, transformation of eukinetic circulation type (CT into hypokinetic CT and absence of sportswomen with hyperkinetic CT. In high class sportswomen there were significant increase of the relative value of physical working capacity (PWC170/kg by 12.33% and tendency to increase of index of functional state (IFS by 9.46%, in sportswomen with qualifications of II–III category PWC170/kg significantly increased by 19.26%, and IFS by 17.87%. Correlation analysis conducted in both periods in the group and separately in high class sportswomen and ones with qualifications of II–III category found the relationship indicating that the increase of PWC170/kg and IFS is associated with the prevalence of hypokinetic CT and parasympathetic ANS influences. In the competitive period

Age, training, and previous experience predict race performance in long-distance inline skaters, not anthropometry.

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

2012-02-01

The association of characteristics of anthropometry, training, and previous experience with race time in 84 recreational, long-distance, inline skaters at the longest inline marathon in Europe (111 km), the Inline One-eleven in Switzerland, was investigated to identify predictor variables for performance. Age, duration per training unit, and personal best time were the only three variables related to race time in a multiple regression, while none of the 16 anthropometric variables were related. Anthropometric characteristics seem to be of no importance for a fast race time in a long-distance inline skating race in contrast to training volume and previous experience, when controlled with covariates. Improving performance in a long-distance inline skating race might be related to a high training volume and previous race experience. Also, doing such a race requires a parallel psychological effort, mental stamina, focus, and persistence. This may be reflected in the preparation and training for the event. Future studies should investigate what motivates these athletes to train and compete.

Cost of enlarged operating zone for an existing Francis runner

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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

Primary and secondary exercise dependence in a community-based sample of road race runners.

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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.

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

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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.

The NLstart2run study: Incidence and risk factors of running-related injuries in novice runners.

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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.

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

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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.

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

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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.

HEART RATE RECOVERY AFTER EXERCISE AND NEURAL REGULATION OF HEART RATE VARIABILITY IN 30-40 YEAR OLD FEMALE MARATHON RUNNERS

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Toshio Matsuoka

2005-03-01

Full Text Available The aim of the present study was to examine the effects of endurance training on heart rate (HR recovery after exercise and cardiac autonomic nervous system (ANS modulation in female marathon runners by comparing with untrained controls. Six female marathon runners (M group aged 32-40 years and eight age-matched untrained females (C group performed a maximum-effort treadmill running exercise. Maximal oxygen uptake (VO2max was measured during the exercise with a gas analyzer connected to subjects through a face mask. Heart rate, blood pressure and blood lactate were measured before and after the exercise. Rating of perceived exertion (RPE to the exercise was obtained immediately after the exercise. Holter ECG was recorded and analyzed with power spectral analysis of heart rate variability (HRV to investigate the cardiac ANS modulation. The M group had significantly higher VO2max, faster HR recovery after exercise, higher Mean RR, SDRR, HF power and lower LF/HF ratio at rest compared with the C group. The M group also presented greater percent decrease of blood pressure after exercise, although their blood pressure after exercise was higher than the C group. It is suggested that endurance training induced significant alterations in cardiac ANS modulation at rest and significant acceleration of HR recovery after exercise in female marathon runners. Faster HR recovery after exercise in the female marathon runners should result from their higher levels of HRV, higher aerobic capacity and exaggerated blood pressure response to exercise compared with untrained controls.

Distance walked and run as improved metrics over time-based energy estimation in epidemiological studies and prevention; evidence from medication use.

Directory of Open Access Journals (Sweden)

Paul T Williams

Full Text Available The guideline physical activity levels are prescribed in terms of time, frequency, and intensity (e.g., 30 minutes brisk walking, five days a week or its energy equivalence and assume that different activities may be combined to meet targeted goals (exchangeability premise. Habitual runners and walkers may quantify exercise in terms of distance (km/day, and for them, the relationship between activity dose and health benefits may be better assessed in terms of distance rather than time. Analyses were therefore performed to test: 1 whether time-based or distance-based estimates of energy expenditure provide the best metric for relating running and walking to hypertensive, high cholesterol, and diabetes medication use (conditions known to be diminished by exercise, and 2 the exchangeability premise.Logistic regression analyses of medication use (dependent variable vs. metabolic equivalent hours per day (METhr/d of running, walking and other exercise (independent variables using cross-sectional data from the National Runners' (17,201 male, 16,173 female and Walkers' Health Studies (3,434 male, 12,384 female.Estimated METhr/d of running and walking activity were 38% and 31% greater, respectively, when calculated from self-reported time than distance in men, and 43% and 37% greater in women, respectively. Percent reductions in the odds for hypertension and high cholesterol medication use per METhr/d run or per METhr/d walked were ≥ 2-fold greater when estimated from reported distance (km/wk than from time (hr/wk. The per METhr/d odds reduction was significantly greater for the distance- than the time-based estimate for hypertension (runners: P<10(-5 for males and P=0.003 for females; walkers: P=0.03 for males and P<10(-4 for females, high cholesterol medication use in runners (P<10(-4 for males and P=0.02 for females and male walkers (P=0.01 for males and P=0.08 for females and for diabetes medication use in male runners (P<10(-3.Although causality

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

Changes in Running Economy, Respiratory Exchange Ratio and VO2max in Runners following a 10-day Altitude Training Camp.

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Diebel, Sebastian R; Newhouse, Ian; Thompson, David S; Johnson, Vineet B K

2017-01-01

Running economy (RE) and VO 2 max are important predictors of endurance performance for elite and semi-elite endurance athletes, with RE being an appropriate predictor in a homogenous running population. Altitude training has been observed to change RE (mL.kg -1 .min -1 ), and VO 2 max due to alterations resulting from acclimatization. This study tracked changes in RE and VO 2 max before and after a 10-day altitude training camp at 1828 meters. VO 2 max, RE expressed calorically, and respiratory exchange ratio (RER), were measured below anaerobic threshold (AT) to observe differences between pre-and post-altitude training. Eight varsity cross-country runners between the ages of 18 and 22 years performed an incremental treadmill test, pre- and post-10-day altitude training. Paired samples t-tests were used to statistically analyze the data. Average RE (VO 2 mL.kg -1 .min -1 ) improved following altitude intervention ( M = 56.44 ± 4.28) compared to pre-altitude training (61.30 ± 7.56). These differences were statistically significant t ( 7 )= 2.71, p =.014. RE expressed as kcals.kg -1 .km -1 improved following altitude training (16.73 ± 2.96) compared to (18.44 ± 4.04) pre-altitude training and was statistically significant t( 7 ) =3.08, p = .008. RER taken during the last minute of steady-state was higher (0.97, ± .019) post-altitude training, compared to (0.90 ± .043) pre-altitude. These differences were statistically significant t ( 7 ) -3.62, p =.008. VO 2 max (mL.kg -1 .min -1 ) was lower in 6 out of 8 participants (63.91, ± 8.65) post-altitude compared to (69.90, ± 10.80) pre-altitude and was statistically significant t( 7 ) = 2.33, p =.026. The observed improvements in RE may be beneficial for endurance athletes competing and/or training at moderate altitudes near 1828 meters.

Validation, verification and evaluation of a Train to Train Distance Measurement System by means of Colored Petri Nets

International Nuclear Information System (INIS)

Song, Haifeng; Liu, Jieyu; Schnieder, Eckehard

2017-01-01

Validation, verification and evaluation are necessary processes to assure the safety and functionality of a system before its application in practice. This paper presents a Train to Train Distance Measurement System (TTDMS), which can provide distance information independently from existing onboard equipment. Afterwards, we proposed a new process using Colored Petri Nets to verify the TTDMS system functional safety, as well as to evaluate the system performance. Three main contributions are carried out in the paper: Firstly, this paper proposes a formalized TTDMS model, and the model correctness is validated using state space analysis and simulation-based verification. Secondly, corresponding checking queries are proposed for the purpose of functional safety verification. Further, the TTDMS performance is evaluated by applying parameters in the formal model. Thirdly, the reliability of a functional prototype TTDMS is estimated. It is found that the procedure can cooperate with the system development, and both formal and simulation-based verifications are performed. Using our process to evaluate and verify a system is easier to read and more reliable compared to executable code and mathematical methods. - Highlights: • A new Train to Train Distance Measurement System. • New approach verifying system functional safety and evaluating system performance by means of CPN. • System formalization using the system property concept. • Verification of system functional safety using state space analysis. • Evaluation of system performance applying simulation-based analysis.

Dose-response relationship of autonomic nervous system responses to individualized training impulse in marathon runners.

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Manzi, Vincenzo; Castagna, Carlo; Padua, Elvira; Lombardo, Mauro; D'Ottavio, Stefano; Massaro, Michele; Volterrani, Maurizio; Iellamo, Ferdinando

2009-06-01

In athletes, exercise training induces autonomic nervous system (ANS) adaptations that could be used to monitor training status. However, the relationship between training and ANS in athletes has been investigated without regard for individual training loads. We tested the hypothesis that in long-distance athletes, changes in ANS parameters are dose-response related to individual volume/intensity training load and could predict athletic performance. A spectral analysis of heart rate (HR), systolic arterial pressure variability, and baroreflex sensitivity by the sequences technique was investigated in eight recreational athletes during a 6-mo training period culminating with a marathon. Individualized training load responses were monitored by a modified training impulse (TRIMP(i)) method, which was determined in each athlete using the individual HR and lactate profiling determined during a treadmill test. Monthly TRIMP(i) steadily increased during the training period. All the ANS parameters were significantly and very highly correlated to the dose of exercise with a second-order regression model (r(2) ranged from 0.90 to 0.99; P marathon. These results suggest that in recreational athletes, ANS adaptations to exercise training are dose related on an individual basis, showing a progressive shift toward a sympathetic predominance, and that LF oscillations in HRV at peak training load could predict athletic achievement in this athlete population.

DIFFERENTIAL DIAGNOSIS OF DEEP GLUTEAL PAIN IN A FEMALE RUNNER WITH PELVIC INVOLVEMENT: A CASE REPORT

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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

Nutritional factors that influence change in bone density and stress fracture risk among young female cross-country runners.

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Nieves, Jeri W; Melsop, Kathryn; Curtis, Meredith; Kelsey, Jennifer L; Bachrach, Laura K; Greendale, Gail; Sowers, Mary Fran; Sainani, Kristin L

2010-08-01

To identify nutrients, foods, and dietary patterns associated with stress fracture risk and changes in bone density among young female distance runners. Two-year, prospective cohort study. Observational data were collected in the course of a multicenter randomized trial of the effect of oral contraceptives on bone health. One hundred and twenty-five female competitive distance runners ages 18-26 years. Dietary variables were assessed with a food frequency questionnaire. Bone mineral density and content (BMD/BMC) of the spine, hip, and total body were measured annually by dual x-ray absorptiometry (DEXA). Stress fractures were recorded on monthly calendars, and had to be confirmed by radiograph, bone scan, or magnetic resonance imaging. Seventeen participants had at least one stress fracture during follow-up. Higher intakes of calcium, skim milk, and dairy products were associated with lower rates of stress fracture. Each additional cup of skim milk consumed per day was associated with a 62% reduction in stress fracture incidence (P stress fracture rate. Potassium intake was also associated with greater gains in hip and whole-body BMD. Copyright © 2010 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Dosimetric characteristics of the Novoste Beta-Cath 90Sr/Y source trains at submillimeter distances

International Nuclear Information System (INIS)

Roa, Dante E.; Song Haijun; Yue Ning; D'Errico, Francesco; Nath, Ravinder

2004-01-01

Measurements were performed on the 30, 40, and 60 mm 90 Sr/Y β-emitter source trains used in the Novoste Beta-Cath system to determine their dosimetric characteristics at submillimeter distances and provide the necessary TG-60 parameters for mapping their dose distributions. These measurements were carried out in a Solid Water TM phantom where MD55-2 Gafchromic TM films were placed in direct contact with a 5 French (F) catheter used for the 30 and 60 mm source trains and a 3.5F catheter used for thinner 30 and 40 mm source trains. A data set consisted of three pieces of Gafchromic film irradiated for periods of 1.5, 5, and 10 minutes, respectively. This 3-film irradiation technique provided reliable dose data at short, intermediate and long distances from a source train. Three data sets per source train were collected in this study. For the 30 mm source train with a 5F catheter, data were collected with the source axis at proximal (0.41 mm) and distal (1.19 mm) positions to the film surface in order to investigate dosimetric effects due to the off centering of the source train lumen within the catheter. Absolute doses were determined by calibrating the Gafchromic film in a high-energy electron beam from a radiotherapy accelerator. The absolute dose rates at a distance of 2 mm along the source trains transverse axis were found to be within 13.7% of the values provided by Novoste. Radial dose functions were within 13% compared to 90 Sr/Y source train data constructed from Soares' 90 Sr/Y single seed data and within 17% and 25% compared to Monte Carlo data by Ye et al., and Wang et al., respectively. Discrepancies of 33% and 19% were observed at short radial distances (≤1 mm) between the Novoste Monte Carlo and the 3.5F and 5F catheter measured data, respectively. The source off centering data showed higher dose contribution from the source train at its distal rather than proximal position. Radial dose function comparisons between the Novoste Monte Carlo and the

Physiological and Biomechanical Mechanisms of Distance Specific Human Running Performance.

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Thompson, M A

2017-08-01

Running events range from 60-m sprints to ultra-marathons covering 100 miles or more, which presents an interesting diversity in terms of the parameters for successful performance. Here, we review the physiological and biomechanical variations underlying elite human running performance in sprint to ultramarathon distances. Maximal running speeds observed in sprint disciplines are achieved by high vertical ground reaction forces applied over short contact times. To create this high force output, sprint events rely heavily on anaerobic metabolism, as well as a high number and large cross-sectional area of type II fibers in the leg muscles. Middle distance running performance is characterized by intermediates of biomechanical and physiological parameters, with the possibility of unique combinations of each leading to high-level performance. The relatively fast velocities in mid-distance events require a high mechanical power output, though ground reaction forces are less than in sprinting. Elite mid-distance runners exhibit local muscle adaptations that, along with a large anaerobic capacity, provide the ability to generate a high power output. Aerobic capacity starts to become an important aspect of performance in middle distance events, especially as distance increases. In distance running events, V˙O2max is an important determinant of performance, but is relatively homogeneous in elite runners. V˙O2 and velocity at lactate threshold have been shown to be superior predictors of elite distance running performance. Ultramarathons are relatively new running events, as such, less is known about physiological and biomechanical parameters that underlie ultra-marathon performance. However, it is clear that performance in these events is related to aerobic capacity, fuel utilization, and fatigue resistance. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology 2017. This work is written by US Government employees and is in

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.

Running from Iliotibial Band Syndrome: A Guide for Preventing Overuse Injuries

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Ramsey, Codi A.

2016-01-01

Iliotbial band syndrome (ITBS) is an overuse injury that affects distance runners and produces a large amount of frustration (and pain) to the runner, coaches and trainers. Treatments for ITBS vary widely and no known cures exist. Many running experts and physicians have prescribed several variations of training programs designed to help runners…

Maximum Power Training and Plyometrics for Cross-Country Running.

Science.gov (United States)

Ebben, William P.

2001-01-01

Provides a rationale for maximum power training and plyometrics as conditioning strategies for cross-country runners, examining: an evaluation of training methods (strength training and maximum power training and plyometrics); biomechanic and velocity specificity (role in preventing injury); and practical application of maximum power training and…

Training for Distance Teaching through Distance Learning.

Science.gov (United States)

Cadorath, Jill; Harris, Simon; Encinas, Fatima

2002-01-01

Describes a mixed-mode bachelor degree course in English language teaching at the Universidad Autonoma de Puebla (Mexico) that was designed to help practicing teachers write appropriate distance education materials by giving them the experience of being distance students. Includes a course outline and results of a course evaluation. (Author/LRW)

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.

A comparative study of classroom and online distance modes of official vocational education and training.

Science.gov (United States)

López Soblechero, Miguel Vicente; González Gaya, Cristina; Hernández Ramírez, Juan José

2014-01-01

The study discussed in this paper had two principal objectives. The first was to evaluate the distance model of official vocational education and training offered by means of a virtual learning platform. The second was to establish that both on-site classroom and online distance modes of vocational education and training can be seen as complementary in terms of responding to the majority of modern educational needs. We performed a comparative study using data and results gathered over the course of eleven academic years for 1,133 of our students enrolled in an official vocational education and training program, leading to the awarding of a certificate as an Administrative Management Expert. The classes were offered by the Alfonso de Avellaneda Vocational Education and Training School, located in the city of Alcalá de Henares near Madrid, Spain. We offered classes both in traditional classroom mode and through online distance learning. This paper begins with a descriptive analysis of the variables we studied; inferential statistical techniques are subsequently applied in order to study the relationships that help form the basis for the conclusions reached. This study's results provide evidence that a broad offering of vocational education and training opportunities will facilitate access to such learning for students who require it, regardless of their age, employment status, or personal circumstances, with the online distance mode playing a fundamental role while also yielding results equivalent to those observed for classroom instruction.

A comparative study of classroom and online distance modes of official vocational education and training.

Directory of Open Access Journals (Sweden)

Miguel Vicente López Soblechero

Full Text Available The study discussed in this paper had two principal objectives. The first was to evaluate the distance model of official vocational education and training offered by means of a virtual learning platform. The second was to establish that both on-site classroom and online distance modes of vocational education and training can be seen as complementary in terms of responding to the majority of modern educational needs. We performed a comparative study using data and results gathered over the course of eleven academic years for 1,133 of our students enrolled in an official vocational education and training program, leading to the awarding of a certificate as an Administrative Management Expert. The classes were offered by the Alfonso de Avellaneda Vocational Education and Training School, located in the city of Alcalá de Henares near Madrid, Spain. We offered classes both in traditional classroom mode and through online distance learning. This paper begins with a descriptive analysis of the variables we studied; inferential statistical techniques are subsequently applied in order to study the relationships that help form the basis for the conclusions reached. This study's results provide evidence that a broad offering of vocational education and training opportunities will facilitate access to such learning for students who require it, regardless of their age, employment status, or personal circumstances, with the online distance mode playing a fundamental role while also yielding results equivalent to those observed for classroom instruction.

Marine oil dietary supplementation reduces delayed onset muscle soreness after a 30 km run

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Baum K

2013-05-01

Full Text Available Klaus Baum,1 Richard D Telford,2 Ross B Cunningham,3 1Trainingsinstitut Prof Baum, Köln, Germany; 2College of Medicine, Biology, and Environment, Australian National University, Canberra, ACT, Australia; 3The Fenner School of Environment and Society, Australian National University, Canberra, ACT, Australia Objective: Runners are prone to delayed onset muscle soreness (DOMS during long distance training. This especially holds for unaccustomed training volumes at moderate to high intensities. We investigated the effects of a marine oil complex, PCSO-524®, derived from the New Zealand green-lipped mussel (formulated as Lyprinol® and Omega XL® on DOMS after a 30 km training run. Methods: Initially, peak oxygen uptake of 32 distance runners (4 female, 28 male; median age 45 years, range 28–53 was measured on a treadmill with a 1.5 km hour-1 increase every 4 minutes starting from 8.5 km hour-1. At least 1-week after this initial test, they participated in a 30 km road run at a speed corresponding to about 70% of their individual peak oxygen uptake on a flat terrain. Before and after (0, 24, and 48 hours the run, blood concentration of creatine kinase (CK were measured and pain sensation was determined (pain scale from 0 = no pain to 10 = extremely painful. Runners were then matched in pairs based on maximal CK and peak oxygen uptake, and allocated randomly into two different groups. One group was supplemented with 400 mg per day of PCSO-524® for 11 weeks, the other group with an olive oil placebo. After that period, CK and pain sensations were remeasured following a second 30 km run at the same speed and on the same terrain. Results: The general pattern of soreness in the PCSO-524® supplemented group was reduced by 1.1 units (standard error 0.41 compared to the placebo (P < 0.05, the effects being greater in lesser trained runners (P < 0.05. CK levels were positively associated with pain sensation (P < 0.05, but trends toward lower CK in the

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

Unchanged Erythrocyte Profile After Exposure to Cryogenic Temperatures in Elder Marathon Runners

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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

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

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 ...

Improving Distance Courses: Understanding Teacher Trainees and their Learning Styles for the design of Teacher Training Courses and Materials at a Distance

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Hisham DZAKIRIA

2004-01-01

Full Text Available Literature on distance education and teacher education seems to show that what we do not know about Distance Teacher Trainees (DTT and their learning process involved exceeds what we know about it. As more DTT enroll in distance education programmes globally, distance education providers and institutions will witness trainees coming with different backgrounds and experiences begin to take advantage of this learning opportunities. One important variable in the effectiveness of distance learning is the preference of the distance learner for a particular learning mode. A key to maintaining distance learners participation in learning lies in understanding the Learning Styles Preferences (LSP and the processes involved.This is also true for teacher training. There is much greater variation in the range of LSP and how to address them when preparing distance training materials and courses. The primary purpose of this paper is to propose ways in which individual learning differences should be accommodated when designing instructional learning materials in print for DTTs. Kolb’s (1984 model on learning cycle and styles are discussed to provide instructional design guidelines which accommodate each stage of the learning cycles and individual differences between DTT in processing and presenting information and knowledge. In addition, issues on teacher education, distance learning, individual differences, and ways in which the ‘differences’ can be accommodated when designing learning materials for DTT are also discussed. This paper resonates the idea and belief that if attempts are made to match learning styles of DTTs and andragogy with content to be learned, distance teacher educators (DTEs and instructors can develop better instructional materials with greater prospects of success. Getting to know and understand the teacher trainees and their learning process involved must first be addressed to facilitate the diverse needs of the Malaysian teacher

Prediction of Running Injuries from Training Load: a Machine Learning Approach.

NARCIS (Netherlands)

Dijkhuis, Talko; Otter, Ruby; Velthuijsen, H.; Lemmink, Koen A.P.M.

2017-01-01

The prediction of the running injuries based on selfreported training data on load is difficult. At present, coaches and researchers have no validated system to predict if a runner has an increased risk of injuries. We aim to develop an algorithm to predict the increase of the risk of a runner to

The baseline serum value of α-amylase is a significant predictor of distance running performance.

Science.gov (United States)

Lippi, Giuseppe; Salvagno, Gian Luca; Danese, Elisa; Tarperi, Cantor; La Torre, Antonio; Guidi, Gian Cesare; Schena, Federico

2015-02-01

This study was planned to investigate whether serum α-amylase concentration may be associated with running performance, physiological characteristics and other clinical chemistry analytes in a large sample of recreational athletes undergoing distance running. Forty-three amateur runners successfully concluded a 21.1 km half-marathon at 75%-85% of their maximal oxygen uptake (VO2max). Blood was drawn during warm up and 15 min after conclusion of the run. After correction for body weight change, significant post-run increases were observed for serum values of alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, bilirubin, creatine kinase (CK), iron, lactate dehydrogenase (LDH), triglycerides, urea and uric acid, whereas the values of body weight, glomerular filtration rate, total and low density lipoprotein-cholesterol were significantly decreased. The concentration of serum α-amylase was unchanged. In univariate analysis, significant associations with running performance were found for gender, VO2max, training regimen and pre-run serum values of α-amylase, CK, glucose, high density lipoprotein-cholesterol, LDH, urea and uric acid. In multivariate analysis, only VO2max (p=0.042) and baseline α-amylase (p=0.021) remained significant predictors of running performance. The combination of these two variables predicted 71% of variance in running performance. The baseline concentration of serum α-amylase was positively correlated with variation of serum glucose during the trial (r=0.345; p=0.025) and negatively with capillary blood lactate at the end of the run (r=-0.352; p=0.021). We showed that the baseline serum α-amylase concentration significantly and independently predicts distance running performance in recreational runners.

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.

A pilot study on quantification of training load: The use of HRV in training practice.

Science.gov (United States)

Saboul, Damien; Balducci, Pascal; Millet, Grégoire; Pialoux, Vincent; Hautier, Christophe

2016-01-01

Recent laboratory studies have suggested that heart rate variability (HRV) may be an appropriate criterion for training load (TL) quantification. The aim of this study was to validate a novel HRV index that may be used to assess TL in field conditions. Eleven well-trained long-distance male runners performed four exercises of different duration and intensity. TL was evaluated using Foster and Banister methods. In addition, HRV measurements were performed 5 minutes before exercise and 5 and 30 minutes after exercise. We calculated HRV index (TLHRV) based on the ratio between HRV decrease during exercise and HRV increase during recovery. HRV decrease during exercise was strongly correlated with exercise intensity (R = -0.70; p HRV changes during exercise and recovery phase are affected by both intensity and physiological impact of the exercise. Since the TLHRV formula takes into account the disturbance and the return to homeostatic balance induced by exercise, this new method provides an objective and rational TL index. However, some simplification of the protocol measurement could be envisaged for field use.

Cracking the code for maintaining quality training in Olympic distance triathlon

DEFF Research Database (Denmark)

Myburgh, Corrie; Hansen, Tobias; Holm Beck, Anders

2017-01-01

OBJECTIVE: High-quality training is a key determinant of performance in the Olympic distance triathlon and is potentially influenced by a unique array of context-specific biopsychosocial factors. Our objective was to explore and describe these factors among squad members of a university-based, el...

Acute and chronic effects of aquatic treadmill training on land treadmill running kinematics: A cross-over and single-subject design approach.

Science.gov (United States)

Bressel, Eadric; Louder, Talin J; Hoover, James P; Roberts, Luke C; Dolny, Dennis G

2017-11-01

The aim of this study was to determine if selected kinematic measures (foot strike index [SI], knee contact angle and overstride angle) were different between aquatic treadmill (ATM) and land treadmill (LTM) running, and to determine if these measures were altered during LTM running as a result of 6 weeks of ATM training. Acute effects were tested using 15 competitive distance runners who completed 1 session of running on each treadmill type at 5 different running speeds. Subsequently, three recreational runners completed 6 weeks of ATM training following a single-subject baseline, intervention and withdrawal experiment. Kinematic measures were quantified from digitisation of video. Regardless of speed, SI values during ATM running (61.3 ± 17%) were significantly greater (P = 0.002) than LTM running (42.7 ± 23%). Training on the ATM did not change (pre/post) the SI (26 ± 3.2/27 ± 3.1), knee contact angle (165 ± 0.3/164 ± 0.8) or overstride angle (89 ± 0.4/89 ± 0.1) during LTM running. Although SI values were different between acute ATM and LTM running, 6 weeks of ATM training did not appear to alter LTM running kinematics as evidenced by no change in kinematic values from baseline to post intervention assessments.

[Problem based learning by distance education and analysis of a training system].

Science.gov (United States)

Dury, Cécile

2004-12-01

This article presents and analyses a training system aiming at acquiring skills in nursing cares. The aims followed are the development: --of an active pedagogic method: learning through problems (LTP); --of the interdisciplinary and intercultural approach, the same problems being solves by students from different disciplines and cultures; --of the use of the new technologies of information and communication (NTIC) so as to enable a maximal "distance" cooperation between the various partners of the project. The analysis of the system shows that the pedagogic aims followed by LTP are reached. The pluridisciplinary and pluricultural approach, to be optimal, requires great coordination between the partners, balance between the groups of students from different countries and disciplines, training and support from the tutors in the use of the distance teaching platform.

Breath acidification in adolescent runners exposed to atmospheric pollution: A prospective, repeated measures observational study

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Van Sickle David

2008-03-01

Full Text Available Abstract Background Vigorous outdoors exercise during an episode of air pollution might cause airway inflammation. The purpose of this study was to examine the effects of vigorous outdoor exercise during peak smog season on breath pH, a biomarker of airway inflammation, in adolescent athletes. Methods We measured breath pH both pre- and post-exercise on ten days during peak smog season in 16 high school athletes engaged in daily long-distance running in a downwind suburb of Atlanta. The association of post-exercise breath pH with ambient ozone and particulate matter concentrations was tested with linear regression. Results We collected 144 pre-exercise and 146 post-exercise breath samples from 16 runners (mean age 14.9 years, 56% male. Median pre-exercise breath pH was 7.58 (interquartile range: 6.90 to 7.86 and did not change significantly after exercise. We observed no significant association between ambient ozone or particulate matter and post-exercise breath pH. However both pre- and post-exercise breath pH were strikingly low in these athletes when compared to a control sample of 14 relatively sedentary healthy adults and to published values of breath pH in healthy subjects. Conclusion Although we did not observe an acute effect of air pollution exposure during exercise on breath pH, breath pH was surprisingly low in this sample of otherwise healthy long-distance runners. We speculate that repetitive vigorous exercise may induce airway acidification.

Kinematic classification of iliotibial band syndrome in runners.

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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.

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…

Face-to-Face or Distance Training: Two Different Approaches To Motivate SMEs to Learn.

Science.gov (United States)

Lawless, Naomi; Allan, John; O'Dwyer, Michele

2000-01-01

Two approaches to training for small/medium-sized enterprises were compared: a British distance learning program and an Irish program offering face-to-face training for micro-enterprises. Both used constructivist, collaborative, and reflective methods. Advantages and disadvantages of each approach were identified. (SK)

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.

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.

Distance learning in english teacher's training: Reflexion activities in discussion forums

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Fernanda Costa Ribas

2016-03-01

Full Text Available In this article we problematize the issues related to teacher’s training in the English language amidst the emersion of new literacies, especially those mediated by digital technologies, based in my experience both as a teacher and a researcher in Degree Courses in Languages, both classroom based and distance learning. Based in referential about teachers’ beliefs, reflexive practices, new literacies, and teachers’ training for the use of technologies, we focus our experience in the development of institutional material for a distance learning teaching degree course, describing some of the activities developed as discussion forums. With that, our aim is to discuss ways to promote the reflection of future teachers about their beliefs and experiences, and the interaction of these with teaching concepts and theories, allowing them to establish connections between theory and practice during practice - in other words, through their engagement in online activities of a subject in a Supervised Internship in English.

Cross-sectional relationships of exercise and age to adiposity in60,617 male runners

Energy Technology Data Exchange (ETDEWEB)

Williams, Paul T.; Pate, Russell R.

2004-06-01

The objective of this report is to assess in men whether exercise affects the estimated age-related increase in adiposity, and contrariwise, whether age affects the estimated exercise-related decrease in adiposity. Cross-sectional analyses of 64,911 male runners who provided data on their body mass index (97.6 percent), waist (91.1 percent), hip (47.1 percent), and chest circumferences (77.9 percent). Between 18 to 55 years old, the decline in BMI with weekly distance run (slope+-SE) was significantly greater in men 25-55 years old (slope+-:-0.036+-0.001 kg/m2 per km/wk) than in younger men (-0.020+-0.002 kg/m 2 per km/wk). Declines in waist circumference with running distance were also significantly greater in older than younger men (P<10-9 for trend),i.e., the slopes decreased progressively from -0.035+-0.004 cm per km/wk in 18-25 year old men to -0.097+-0.003 cm per km/wk in 50-55 year old men. Increases in BMI with age were greater for men who ran under 16km/wk than for longer distance runners. Waist circumference increased with age at all running levels, but the increase appeared to diminish by running further (0.259+-0.015 cm per year if running<8 km/wk and 0.154+-0.003 cm per year for>16 km/wk). In men over 50 years old, BMI declined -0.038+-0.001 kg/m2 per km/wk run when adjusted for age and declined -0.054+-0.003 kg/m2 (increased 0.021+-0.007 cm) per year of age when adjusted for running distance. Their waist circumference declined-0.096+-0.002 cm per km/wk run when adjusted for age and increased 0.021+-0.007 cm per year of age when adjusted for running distance. These cross-sectional data suggest that age and vigorous exercise interact with each other in affecting mens adiposity, and support the proposition that vigorous physical activity must increase with age to prevent middle-age weight gain. We estimate that a man who ran 16 km/wk at age 25 would need to increase their weekly running distance by 65.7 km/wk by age 50 in order to maintain his same waist

Skeletal muscle architectural adaptations to marathon run training.

Science.gov (United States)

Murach, Kevin; Greever, Cory; Luden, Nicholas D

2015-01-01

We assessed lateral gastrocnemius (LG) and vastus lateralis (VL) architecture in 16 recreational runners before and after 12 weeks of marathon training. LG fascicle length decreased 10% while pennation angle increased 17% (p training can modify skeletal muscle architectural features.

ANALYSIS OF EFFICIENCY OF THE DISTANCE TRAINING SYSTEM IN THE PROCESS OF COMPETENCY VERIFICATION

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Kravtsovа L.

2017-12-01

Full Text Available The Kherson State Maritime Academy conducts experimental research on the integration of the educational process on the basis of a competence approach to the state educational policy of Ukraine. One of the directions of this work is the creation and implementation of a distance education platform to support the educational process in the Kherson Maritime Academy. The distance learning system of KSMA is built on the basis of the open Moodle platform, which offers a wide range of opportunities to fully support the learning process in the remote environment, namely, a variety of ways of presenting the training material, testing knowledge and monitoring progress. The peculiarity of the developed system is that the effectiveness of the training strategy is provided by taking into account the psychological characteristics of the user contingent, the ultimate goal of training, the motivation of the whole process of education, namely, the specifics of the seaman's profession. One of the main directions of the work was a complete replacement of the classical methodology for conducting the examination session for complex testing, which covers all disciplines from 1 to 5 courses of study and is conducted on the basis of a distance education platform. The results of the experiment showed that own site of distance learning is an effective tool for studying the teaching material and for testing the quality of its learning.

Comparison of systemic cytokine responses after a long distance triathlon and a 100-km run: relationship to metabolic and inflammatory processes.

Science.gov (United States)

Gomez-Merino, Danielle; Drogou, Catherine; Guezennec, Charles Yannick; Burnat, Pascal; Bourrilhon, Cyprien; Tomaszewski, Armand; Milhau, Stéphane; Chennaoui, Mounir

2006-06-01

Suggested mechanisms for the systemic, circulating cytokinemia observed during heavy physical exertion include inflammation and energy demand. We compared cytokine levels and examined the underlying physiological mechanisms between a long-distance triathlon and a 100-km run, two endurance races of similar duration but characterized by differences in muscle strain. Blood samples were collected from 12 triathletes (34.8 +/- 1.4 yr) and 11 runners (42.4 +/- 2.2 yr) the day before and at the end of races (T1, R1), and 24 h and 7 days post-race (R2, R3). At R1, significant race-related differences were observed, with greater increases in plasma levels of interleukins (IL)-6, IL-1ra, and IL-10 in the triathletes than in the runners, while levels of the chemokine IL-8 increased solely in the runners (P long distance triathlon and a 100-km run suggested that IL-6 and IL-8 could be employed as respective markers of the intensity of the muscular activity required for substrate availability and vascular inflammation.

Who uses running apps and sports watches? Determinants and consumer profiles of event runners' usage of running-related smartphone applications and sports watches.

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Mark Janssen

Full Text Available Individual and unorganized sports with a health-related focus, such as recreational running, have grown extensively in the last decade. Consistent with this development, there has been an exponential increase in the availability and use of electronic monitoring devices such as smartphone applications (apps and sports watches. These electronic devices could provide support and monitoring for unorganized runners, who have no access to professional trainers and coaches. The purpose of this paper is to gain insight into the characteristics of event runners who use running-related apps and sports watches. This knowledge is useful from research, design, and marketing perspectives to adequately address unorganized runners' needs, and to support them in healthy and sustainable running through personalized technology. Data used in this study are drawn from the standardized online Eindhoven Running Survey 2014 (ERS14. In total, 2,172 participants in the Half Marathon Eindhoven 2014 completed the questionnaire (a response rate of 40.0%. Binary logistic regressions were used to analyze the impact of socio-demographic variables, running-related variables, and psychographic characteristics on the use of running-related apps and sports watches. Next, consumer profiles were identified. The results indicate that the use of monitoring devices is affected by socio-demographics as well as sports-related and psychographic variables, and this relationship depends on the type of monitoring device. Therefore, distinctive consumer profiles have been developed to provide a tool for designers and manufacturers of electronic running-related devices to better target (unorganized runners' needs through personalized and differentiated approaches. Apps are more likely to be used by younger, less experienced and involved runners. Hence, apps have the potential to target this group of novice, less trained, and unorganized runners. In contrast, sports watches are more likely to

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, ...

Determination of Br in blood of amateur runners using NAA and ITS correlation with adopted physical training

International Nuclear Information System (INIS)

Kovacs, Luciana; Zamboni, Cibele B.; Nunes, Lazaro A.S.; Lourenco, Thiago F.; Macedo, Denise V.

2013-01-01

Bromine (Br) is one of the most abundant trace elements in the biosphere, in the human body is present in blood (as bromide), lungs, liver and hair. There is no evidence in humans of bromide concentration in any particular organ that might indicate a specific physiological function and not enough information is available on bromine metabolism but, some studies report its use by eosinophilic leukocytes for immune defense and electrolytic balance. In this study the Br levels were determined in Brazilian amateur athlete's blood that performing physical exercise at (Laboratorio de Bioquimica do Exercicio (LABEX/UNICAMP-Brazil). The samples were collected from twenty six male athletes, ranging from 18 to 26 years old, at rest. The blood samples were irradiated in the nuclear reactor (IEA-R1, 3-4.5MW, pool type) at IPEN/Sao Paulo - Brazil and were analyzed using Neutron Activation Analyses (NAA) technique. These results were compared with the control group (subjects of same age but not involved with physical activities). The range established at rest for amateur runner (0.0040 - 0.0096 gL -1 ) when compared with control group (0.0074 - 0.0306 gL -1 ) suggests that there is a dependency of these limits in the function of the adopted physical training. (author)

Determination of Br in blood of amateur runners using NAA and ITS correlation with adopted physical training

Energy Technology Data Exchange (ETDEWEB)

Kovacs, Luciana; Zamboni, Cibele B., E-mail: lukovacs@gmail.com, E-mail: czamboni@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Nunes, Lazaro A.S.; Lourenco, Thiago F.; Macedo, Denise V., E-mail: lazaroalessandro@yahoo.com.br, E-mail: thiago_fl@yahoo.com.br, E-mail: denivevm@unicamp.br [Universidade de Campinas (LABEX/UNICAMP), Campinas, SP (Brazil). Lab. de Bioquimica do Exercicio

2013-07-01

Bromine (Br) is one of the most abundant trace elements in the biosphere, in the human body is present in blood (as bromide), lungs, liver and hair. There is no evidence in humans of bromide concentration in any particular organ that might indicate a specific physiological function and not enough information is available on bromine metabolism but, some studies report its use by eosinophilic leukocytes for immune defense and electrolytic balance. In this study the Br levels were determined in Brazilian amateur athlete's blood that performing physical exercise at (Laboratorio de Bioquimica do Exercicio (LABEX/UNICAMP-Brazil). The samples were collected from twenty six male athletes, ranging from 18 to 26 years old, at rest. The blood samples were irradiated in the nuclear reactor (IEA-R1, 3-4.5MW, pool type) at IPEN/Sao Paulo - Brazil and were analyzed using Neutron Activation Analyses (NAA) technique. These results were compared with the control group (subjects of same age but not involved with physical activities). The range established at rest for amateur runner (0.0040 - 0.0096 gL{sup -1}) when compared with control group (0.0074 - 0.0306 gL{sup -1}) suggests that there is a dependency of these limits in the function of the adopted physical training. (author)

Eighteen days of "living high, training low" stimulate erythropoiesis and enhance aerobic performance in elite middle-distance runners

DEFF Research Database (Denmark)

Brugniaux, Julien V; Schmitt, Laurent; Robach, Paul

2005-01-01

The efficiency of "living high, training low" (LHTL) remains controversial, despite its wide utilization. This study aimed to verify whether maximal and/or submaximal aerobic performance were modified by LHTL and whether these effects persist for 15 days after returning to normoxia. Last, we trie...

Presença de fatores de risco de doenças cardiovasculares e de lesões em praticantes de corrida de rua Presence of cardiovascular risck factors and injuries in road runners

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Jaqueline de Castro Ishida

2013-03-01

Full Text Available Este estudo descreveu as características antropométricas e presença de fatores de riscos cardiovasculares (Parte1 bem como a ocorrência de lesões (Parte 2 em corredores de rua. Índice de massa corporal, pressão arterial (PA, circunferência abdominal (CA e presença de lesões foram avaliadas em 94 corredores. Destes, 38,5% eram hipertensos auto-referidos, mas 41,9% estavam com a PA alterada no dia. Dentre os auto-referidos sem problemas de saúde, foram encontradas alterações na PA (42%, na CA (9,8% e 6% apresentaram risco cardiovascular moderado. Verificou-se que 34% já sofreram lesão, sendo que 67,7% foram derivadas de treinos ou competições. Idade, distância da prova e realização de outras atividades foram associados com a ocorrência de lesão. Os resultados do presente estudo nos permitem concluir que os praticantes de pedestrianismo apresentam uma condição física propícia ao comprometimento cardiovascular durante uma prova e ao surgimento de lesões, sugerindo campanhas de conscientização sobre a condição de saúde neste público.This study investigated the anthropometric characteristics and the presence of cardiovascular risk factors (Part 1 as well as occurrence of injuries (Part 2 in road runners. Body mass index, blood pressure (BP, abdominal circumference (AC and incidence of injuries were evaluated in 94 road runners. Among the participants, 38,5% self-reported as hypertensive, but 41,7% from total had altered BP. Among healthy runners, it was found alterations on BP (42%, AC (9.8% and 6% presented moderated cardiovascular risk. It was observed that 34% already suffered some injuries and 67.7% derived from training and competition. Age, distance of the running and practice of other activities were associated with presence of injury. The results of the present study allow us to conclude that road runners have a physical condition that facilitates the cardiovascular event during the competition and that

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.

A Distance Education Model for Training Substance Abuse Treatment Providers in Cognitive-Behavioral Therapy

Science.gov (United States)

Watson, Donnie W.; Rawson, Richard R.; Rataemane, Solomon; Shafer, Michael S.; Obert, Jeanne; Bisesi, Lorrie; Tanamly, Susie

2003-01-01

This paper presents a rationale for the use of a distance education approach in the clinical training of community substance abuse treatment providers. Developing and testing new approaches to the clinical training and supervision of providers is important in the substance abuse treatment field where new information is always available. A…

On the importance of the distance measures used to train and test knowledge-based potentials for proteins.

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Martin Carlsen

Full Text Available Knowledge-based potentials are energy functions derived from the analysis of databases of protein structures and sequences. They can be divided into two classes. Potentials from the first class are based on a direct conversion of the distributions of some geometric properties observed in native protein structures into energy values, while potentials from the second class are trained to mimic quantitatively the geometric differences between incorrectly folded models and native structures. In this paper, we focus on the relationship between energy and geometry when training the second class of knowledge-based potentials. We assume that the difference in energy between a decoy structure and the corresponding native structure is linearly related to the distance between the two structures. We trained two distance-based knowledge-based potentials accordingly, one based on all inter-residue distances (PPD, while the other had the set of all distances filtered to reflect consistency in an ensemble of decoys (PPE. We tested four types of metric to characterize the distance between the decoy and the native structure, two based on extrinsic geometry (RMSD and GTD-TS*, and two based on intrinsic geometry (Q* and MT. The corresponding eight potentials were tested on a large collection of decoy sets. We found that it is usually better to train a potential using an intrinsic distance measure. We also found that PPE outperforms PPD, emphasizing the benefits of capturing consistent information in an ensemble. The relevance of these results for the design of knowledge-based potentials is discussed.

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.

Prevalence of pathologic findings in asymptomatic knees of marathon runners before and after a competition in comparison with physically active subjects-a 3.0 T magnetic resonance imaging study.

Science.gov (United States)

Stahl, Robert; Luke, Anthony; Ma, C Benjamin; Krug, Roland; Steinbach, Lynne; Majumdar, Sharmila; Link, Thomas M

2008-07-01

To determine the prevalence of pathologic findings in asymptomatic knees of marathon runners before and after a competition in comparison with physically active subjects. To compare the diagnostic performance of cartilage-dedicated magnetic resonance imaging (MRI) sequences at 3.0 T. Ten marathon runners underwent 3.0 T MRI 2-3 days before and after competition. Twelve physically active asymptomatic subjects not performing long-distance running were examined as controls. Pathologic condition was assessed with the whole-organ magnetic resonance imaging score (WORMS). Cartilage abnormalities and bone marrow edema pattern (BMEP) were quantified. Visualization of cartilage pathology was assessed with intermediate-weighted fast spin-echo (IM-w FSE), fast imaging employing steady-state acquisition (FIESTA) and T1-weighted three-dimensional (3D) high-spatial-resolution volumetric fat-suppressed spoiled gradient-echo (SPGR) MRI sequences. Eight of ten marathon runners and 7/12 controls showed knee abnormality. Slightly more and larger cartilage abnormalities, and BMEP, in marathon runners yielded higher but not significantly different WORMS (P > 0.05) than in controls. Running a single marathon did not alter MR findings substantially. Cartilage abnormalities were best visualized with IM-w FSE images (P marathon runners and also in active subjects participating in other recreational sports. IM-w FSE sequences delineated more cartilage MR imaging abnormalities than did FIESTA and SPGR sequences.

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

A 2-Year Prospective Cohort Study of Overuse Running Injuries: The Runners and Injury Longitudinal Study (TRAILS).

Science.gov (United States)

Messier, Stephen P; Martin, David F; Mihalko, Shannon L; Ip, Edward; DeVita, Paul; Cannon, D Wayne; Love, Monica; Beringer, Danielle; Saldana, Santiago; Fellin, Rebecca E; Seay, Joseph F

2018-05-01

The National Center for Injury Prevention and Control, noting flaws in previous running injury research, called for more rigorous prospective designs and comprehensive analyses to define the origin of running injuries. To determine the risk factors that differentiate recreational runners who remain uninjured from those diagnosed with an overuse running injury during a 2-year observational period. Cohort study; Level of evidence, 2. Inclusion criteria were running a minimum of 5 miles per week and being injury free for at least the past 6 months. Data were collected at baseline on training, medical and injury histories, demographics, anthropometrics, strength, gait biomechanics, and psychosocial variables. Injuries occurring over the 2-year observation period were diagnosed by an orthopaedic surgeon on the basis of predetermined definitions. Of the 300 runners who entered the study, 199 (66%) sustained at least 1 injury, including 73% of women and 62% of men. Of the injured runners, 111 (56%) sustained injuries more than once. In bivariate analyses, significant ( P ≤ .05) factors at baseline that predicted injury were as follows: Short Form Health Survey-12 mental component score (lower mental health-related quality of life), Positive and Negative Affect Scale negative affect score (more negative emotions), sex (higher percentage of women were injured), and knee stiffness (greater stiffness was associated with injury); subsequently, knee stiffness was the lone significant predictor of injury (odds ratio = 1.18) in a multivariable analysis. Flexibility, quadriceps angle, arch height, rearfoot motion, strength, footwear, and previous injury were not significant risk factors for injury. The results of this study indicate the following: (1) among recreational runners, women sustain injuries at a higher rate than men; (2) greater knee stiffness, more common in runners with higher body weights (≥80 kg), significantly increases the odds of sustaining an overuse running

The essence of training trainers in the context of distance education

Directory of Open Access Journals (Sweden)

Yudy Alexandra Molina-Hurtado

2016-12-01

mobilization of knowledge in concrete situations and different scenarios. The objective of the article focuses on the importance of the training of trainers in the context of distance education so characterized, on the one hand, the trainer as a person who refines and contemplates his practice from a surrounding reality that impels the formation of values ethical, human, political, economic, social and immersed cultic in the role of teachers in the twenty-first century, and on the other hand, teachers in training as critical beings, advocates and peacemakers to think as teachers for life. Under this, a reflection between teacher training and professional development to the challenges that teachers face in training regarding their teaching practices supported from teaching and affirmed in the classroom through the teaching process is presented under the staging of competitions and performances from processes that generate autonomy to face the complex world in which we live.

US Air Force 1989 Research Initiation Program. Volume 4.

Science.gov (United States)

1992-06-25

1982, Epperson, Burton and Bernauer investigated 24 individuals divided into 3 separate exercise training groups ( runners , weight lifters and control...muscle fiber types in power lifters, distance runners and untrained 93-31 subjects. Eur J Physiol 1976; 363:19-26. 47. Shrout PE, Fleiss JL. Intraclass...and Gilmore, 1983; Stokes, Wickens, and Kite , 1990). Thus, animated mimic displays provide representations of the important components, systems, or

A Mismatch Between Athlete Practice and Current Sports Nutrition Guidelines Among Elite Female and Male Middle- and Long-Distance Athletes.

Science.gov (United States)

Heikura, Ida A; Stellingwerff, Trent; Mero, Antti A; Uusitalo, Arja Leena Tuulia; Burke, Louise M

2017-08-01

Contemporary nutrition guidelines promote a variety of periodized and time-sensitive recommendations, but current information regarding the knowledge and practice of these strategies among world-class athletes is limited. The aim of this study was to investigate this theme by implementing a questionnaire on dietary periodization practices in national/international level female (n = 27) and male (n = 21) middle- and long-distance runners/race-walkers. The questionnaire aimed to gain information on between and within-day dietary choices, as well as timing of pre- and posttraining meals and practices of training with low or high carbohydrate (CHO) availability. Data are shown as percentage (%) of all athletes, with differences in responses between subgroups (sex or event) shown as Chi-square x 2 when p nutrition recovery recommendations. However, very few athletes deliberately undertake some contemporary dietary periodization approaches, such as training in the fasted state or periodically restricting CHO intake. This study suggests mismatches between athlete practice and current and developing sports nutrition guidelines.

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.

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.

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.

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

Similarities and Differences in Pacing Patterns in a 161-km and 101-km Ultra-Distance Road Race.

Science.gov (United States)

Tan, Philip L S; Tan, Frankie H Y; Bosch, Andrew N

2016-08-01

Tan, PLS, Tan, FHY, and Bosch, AN. Similarities and differences in pacing patterns in a 161-km and 101-km ultra-distance road race. J Strength Cond Res 30(8): 2145-2155, 2016-The purpose of this study was to establish and compare the pacing patterns of fast and slow finishers in a tropical ultra-marathon. Data were collected from the Craze Ultra-marathon held on the 22nd and 21st of September in 2012 and 2013, respectively. Finishers of the 161-km (N = 47) and 101-km (N = 120) categories of the race were divided into thirds (groups A-C) by merit of finishing time. Altogether, 17 and 11 split times were recorded for the 161-km and 101-km finishers, respectively, and used to calculate the mean running speed for each distance segment. Running speed for the first segment was normalized to 100, with all subsequent splits adjusted accordingly. Running speed during the last 5 km was calculated against the mean race pace to establish the existence of an end spurt. A reverse J-shaped pacing profile was demonstrated in all groups for both distance categories and only 38% of the finishers executed an end spurt. In the 101-km category, in comparison with groups B and C, group A maintained a significantly more even pace (p = 0.013 and 0.001, respectively) and completed the race at a significantly higher percent of initial starting speed (p = 0.001 and 0.001, respectively). Descriptive data also revealed that the top 5 finishers displayed a "herd-behavior" by staying close to the lead runner in the initial portion of the race. These findings demonstrate that to achieve a more even pace, recreational ultra-runners should adopt a patient sustainable starting speed, with less competitive runners setting realistic performance goals whereas competitive runners with a specific time goal to consider running in packs of similar pace.

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

Distance Learning

National Research Council Canada - National Science Library

Braddock, Joseph

1997-01-01

A study reviewing the existing Army Distance Learning Plan (ADLP) and current Distance Learning practices, with a focus on the Army's training and educational challenges and the benefits of applying Distance Learning techniques...

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.

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.

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, ...

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

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.

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.

Risk factors for lower extremity injuries among half marathon and marathon runners of the Lage Landen Marathon Eindhoven 2012 : A prospective cohort study in the Netherlands

NARCIS (Netherlands)

Poppel van, D.; de Koning, J; Verhagen, Arianne P; Scholten-Peeters, G G M

To determine risk factors for running injuries during the Lage Landen Marathon Eindhoven 2012. Prospective cohort study. Population-based study. This study included 943 runners. Running injuries after the Lage Landen Marathon. Sociodemographic and training-related factors as well as lifestyle

The Relationship between Field Tests of Anaerobic Power and 10-km Run Performance.

Science.gov (United States)

Sinnett, Aaron M.; Berg, Kris; Latin, Richard W.; Noble, John M.

2001-01-01

Investigated the relationship between several field tests of anaerobic power (e.g., +various sprints, vertical jumps, and a plyometric leap) and distance running performance in trained adult male and female runners. Results indicate that anaerobic power is significantly related to distance running performance and may explain a meaningful…

Effects of training and anthropometric factors on marathon and 100 km ultramarathon race performance

Directory of Open Access Journals (Sweden)

Tanda G

2015-04-01

Full Text Available Giovanni Tanda,1 Beat Knechtle2,3 1Polytechnic School, University of Genoa, Genoa, Italy; 2Gesundheitszentrum St Gallen, St Gallen, 3Institute of Primary Care, University of Zurich, Zurich, Switzerland Background: Marathon (42 km and 100 km ultramarathon races are increasing in popularity. The aim of the present study was to investigate the potential associations of anthropometric and training variables with performance in these long-distance running competitions. Methods: Training and anthropometric data from a large cohort of marathoners and 100 km ultramarathoners provided the basis of this work. Correlations between training and anthropometric indices of subjects and race performance were assessed using bivariate and multiple regression analyses. Results: A combination of volume and intensity in training was found to be suitable for prediction of marathon and 100 km ultramarathon race pace. The relative role played by these two variables was different, in that training volume was more important than training pace for the prediction of 100 km ultramarathon performance, while the opposite was found for marathon performance. Anthropometric characteristics in terms of body fat percentage negatively affected 42 km and 100 km race performance. However, when this factor was relatively low (ie, less than 15% body fat, the performance of 42 km and 100 km races could be predicted solely on the basis of training indices. Conclusion: Mean weekly training distance run and mean training pace were key predictor variables for both marathon and 100 km ultramarathon race performance. Predictive correlations for race performance are provided for runners with a relatively low body fat percentage. Keywords: running, performance, training indices, body fat, sports training

Health Risk Factors Associated with Acute Respiratory Illness Among U.S. Army Recruits Attending Basic Combat Training

Science.gov (United States)

2012-06-11

Competitive athletes recognize peak performance on the field requires consistent intense practice off the field. Recreational sports enthusiasts to Olympic...challenging as a first time marathon runner. Recreational runners tend to run at comfortable distances and intensities, competitive athletes...level of aerobic fitness, as reflected by poor performance on the initial one-mile run test, may experience increased ARI incidence as 3   a result

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

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

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.

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...

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...

New approaches to training specialists of preschool education in the transition to distance learning

Directory of Open Access Journals (Sweden)

Nadiia Lazarovych

2017-03-01

Full Text Available The paper analyzes the features of professional training of pre-school education indistance learning. The efficiency of the use of a mixed form of education for students of “earlychildhood education”. Describes the main conditions for successful use ofdistance learningfor the training of future teachers.Key words: information space, distance learning, information technology (IT, earlychildhood education, personal and psychological characteristics, educational features

Prevalence of pathologic findings in asymptomatic knees of marathon runners before and after a competition in comparison with physically active subjects - a 3.0 T magnetic resonance imaging study

International Nuclear Information System (INIS)

Stahl, Robert; Luke, Anthony; Ma, C.B.; Krug, Roland; Steinbach, Lynne; Majumdar, Sharmila; Link, Thomas M.

2008-01-01

To determine the prevalence of pathologic findings in asymptomatic knees of marathon runners before and after a competition in comparison with physically active subjects. To compare the diagnostic performance of cartilage-dedicated magnetic resonance imaging (MRI) sequences at 3.0 T. Ten marathon runners underwent 3.0 T MRI 2-3 days before and after competition. Twelve physically active asymptomatic subjects not performing long-distance running were examined as controls. Pathologic condition was assessed with the whole-organ magnetic resonance imaging score (WORMS). Cartilage abnormalities and bone marrow edema pattern (BMEP) were quantified. Visualization of cartilage pathology was assessed with intermediate-weighted fast spin-echo (IM-w FSE), fast imaging employing steady-state acquisition (FIESTA) and T1-weighted three-dimensional (3D) high-spatial-resolution volumetric fat-suppressed spoiled gradient-echo (SPGR) MRI sequences. Eight of ten marathon runners and 7/12 controls showed knee abnormality. Slightly more and larger cartilage abnormalities, and BMEP, in marathon runners yielded higher but not significantly different WORMS (P > 0.05) than in controls. Running a single marathon did not alter MR findings substantially. Cartilage abnormalities were best visualized with IM-w FSE images (P < 0.05). A high prevalence of knee abnormalities was found in marathon runners and also in active subjects participating in other recreational sports. IM-w FSE sequences delineated more cartilage MR imaging abnormalities than did FIESTA and SPGR sequences. (orig.)

Prevalence of pathologic findings in asymptomatic knees of marathon runners before and after a competition in comparison with physically active subjects - a 3.0 T magnetic resonance imaging study

Energy Technology Data Exchange (ETDEWEB)

Stahl, Robert [University of California, San Francisco, Musculoskeletal and Quantitative Imaging Group, Department of Radiology, San Francisco, CA (United States); Ludwig Maximilians University of Munich, Department of Clinical Radiology, University Hospitals-Campus Grosshadern, Munich (Germany); Luke, Anthony [University of California, San Francisco, Department of Orthopedic Surgery, San Francisco, CA (United States); University of California, San Francisco, Department of Family and Community Medicine, San Francisco, CA (United States); Ma, C.B. [University of California, San Francisco, Department of Orthopedic Surgery, San Francisco, CA (United States); Krug, Roland; Steinbach, Lynne; Majumdar, Sharmila; Link, Thomas M. [University of California, San Francisco, Musculoskeletal and Quantitative Imaging Group, Department of Radiology, San Francisco, CA (United States)

2008-07-15

To determine the prevalence of pathologic findings in asymptomatic knees of marathon runners before and after a competition in comparison with physically active subjects. To compare the diagnostic performance of cartilage-dedicated magnetic resonance imaging (MRI) sequences at 3.0 T. Ten marathon runners underwent 3.0 T MRI 2-3 days before and after competition. Twelve physically active asymptomatic subjects not performing long-distance running were examined as controls. Pathologic condition was assessed with the whole-organ magnetic resonance imaging score (WORMS). Cartilage abnormalities and bone marrow edema pattern (BMEP) were quantified. Visualization of cartilage pathology was assessed with intermediate-weighted fast spin-echo (IM-w FSE), fast imaging employing steady-state acquisition (FIESTA) and T1-weighted three-dimensional (3D) high-spatial-resolution volumetric fat-suppressed spoiled gradient-echo (SPGR) MRI sequences. Eight of ten marathon runners and 7/12 controls showed knee abnormality. Slightly more and larger cartilage abnormalities, and BMEP, in marathon runners yielded higher but not significantly different WORMS (P > 0.05) than in controls. Running a single marathon did not alter MR findings substantially. Cartilage abnormalities were best visualized with IM-w FSE images (P < 0.05). A high prevalence of knee abnormalities was found in marathon runners and also in active subjects participating in other recreational sports. IM-w FSE sequences delineated more cartilage MR imaging abnormalities than did FIESTA and SPGR sequences. (orig.)

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 ...

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.

Six Sessions of Sprint Interval Training Improves Running Performance in Trained Athletes.

Science.gov (United States)

Koral, Jerome; Oranchuk, Dustin J; Herrera, Roberto; Millet, Guillaume Y

2018-03-01

Koral, J, Oranchuk, DJ, Herrera, R, and Millet, GY. Six sessions of sprint interval training improves running performance in trained athletes. J Strength Cond Res 32(3): 617-623, 2018-Sprint interval training (SIT) is gaining popularity with endurance athletes. Various studies have shown that SIT allows for similar or greater endurance, strength, and power performance improvements than traditional endurance training but demands less time and volume. One of the main limitations in SIT research is that most studies were performed in a laboratory using expensive treadmills or ergometers. The aim of this study was to assess the performance effects of a novel short-term and highly accessible training protocol based on maximal shuttle runs in the field (SIT-F). Sixteen (12 male, 4 female) trained trail runners completed a 2-week procedure consisting of 4-7 bouts of 30 seconds at maximal intensity interspersed by 4 minutes of recovery, 3 times a week. Maximal aerobic speed (MAS), time to exhaustion at 90% of MAS before test (Tmax at 90% MAS), and 3,000-m time trial (TT3000m) were evaluated before and after training. Data were analyzed using a paired samples t-test, and Cohen's (d) effect sizes were calculated. Maximal aerobic speed improved by 2.3% (p = 0.01, d = 0.22), whereas peak power (PP) and mean power (MP) increased by 2.4% (p = 0.009, d = 0.33) and 2.8% (p = 0.002, d = 0.41), respectively. TT3000m was 6% shorter (p training in the field significantly improved the 3,000-m run, time to exhaustion, PP, and MP in trained trail runners. Sprint interval training in the field is a time-efficient and cost-free means of improving both endurance and power performance in trained athletes.

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.

Going beyond Kirkpatrick's Training Evaluation Model: The Role of Workplace Factors in Distance Learning Transfer

Science.gov (United States)

Aluko, F. R.; Shonubi, O. K.

2014-01-01

This article emanates from a longitudinal study of the impact of a distance education programme for teacher training on graduates' job performance, in which the authors built on the findings of a previous pilot study. After using Kirkpatrick's Training Evaluation Model in a previous study, one of the authors found there to be a strong relationship…

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.

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.

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.

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

Athletic altitude training protocols and their application in preparation for mountainous operations.

Science.gov (United States)

Heil, K M; Keenan, A C M

2014-01-01

In recent years, small scale counter-insurgency and expeditionary operations have frequently taken place in mountainous, high-altitude areas. Preparation of soldiers for these environments has typically focussed on extended stays at altitude to ensure physiological acclimatisation. However, with the likelihood that future UK deployments may be unpredictable and thus with little time for preparation, is there a means by which the same acclimatisation may be achieved? The field of athletics has been researching such adaptations since the rise of the elite North African long-distance runners in the 1960s. These athletes all lived high above sea level and had become accustomed to performing in the relatively hypoxic environment found at high altitudes. The research has focussed on eliciting physiological acclimatisation in as short a time as possible, while maintaining the ability to train at the correct intensity. In the following review of altitude training we highlight areas for future investigation and assess whether protocols developed for athletes can be applied to military personnel.

Technical and tactical action modeling of highly trained athletes specializing in breaststroke swimming at various length distances

Directory of Open Access Journals (Sweden)

Olga Pilipko

2017-08-01

Full Text Available Purpose: definition of model parameters of technical and tactical actions of highly trained athletes specializing in breaststroke swimming at various length distances. Material & Methods: analysis of literary sources, video shooting, timing, methods of mathematical data processing. The contingent of the surveyed was made up of athletes who specialized in distances of 50, 100 and 200 meters in breaststroke swimming and had the level of sports qualification of master of sports of Ukraine, Master of Sports of International grade. Result: authors found that the technical and tactical actions of highly trained athletes during the swim of distances of 50, 100 and 200 meters by the breaststroke have their own characteristics; degree of influence of speed, pace and "step" of the strokes cycle on the result of swim distances of 50, 100 and 200 meters is determined; developed their model characteristics. Conclusion: the definition of distance specialization in breaststroke swimming should be carried out taking into account the compliance of individual indicators of technical and tactical actions of athletes to model parameters.

The 5- or 10-km Marikenloop Run: A Prospective Study of the Etiology of Running-Related Injuries in Women.

Science.gov (United States)

van der Worp, Maarten P; de Wijer, Anton; van Cingel, Robert; Verbeek, André L M; Nijhuis-van der Sanden, Maria W G; Staal, J Bart

2016-06-01

Study Design Prospective cohort. Background The popularity of running events is still growing, particularly among women; however, little is known about the risk factors for running-related injuries in female runners. Objectives The aims of this study were to determine the incidence and characteristics (site and recurrence) of running-related injuries and to identify specific risk factors for running-related injuries among female runners training for a 5- or 10-km race. Methods Four hundred thirty-five women registered for the Marikenloop run of 5 or 10 km were recruited. Follow-up data were collected over 12 weeks using questionnaires, starting 8 weeks before the event and ending 4 weeks after the event. Two orthopaedic tests (navicular drop test and extension of the first metatarsophalangeal joint) were performed in the 8 weeks before the event. Running-related injuries, defined as running-related pain of the lower back and/or the lower extremity that restricted running for at least 1 day, were assessed at 1-, 2-, and 3-month follow-ups. Results Of 417 female runners with follow-up data (96%), 93 runners (22.3%) reported 109 running-related injuries, mainly of the hip/groin, knee, and lower leg. Multivariable Cox regression analysis showed that a weekly training distance of more than 30 km (hazard ratio = 3.28; 95% confidence interval [CI]: 1.23, 8.75) and a previous running injury longer than 12 months prior (hazard ratio = 1.88; 95% CI: 1.03, 3.45) were associated with the occurrence of running-related injuries. Conclusion Hip/groin, knee, and lower-leg injuries were common among female runners. Only weekly training distance (greater than 30 km) and previous running injury (greater than 12 months prior) were associated with running-related injuries in female runners training for a 5- or 10-km event. Level of Evidence Etiology, 2b. J Orthop Sports Phys Ther 2016;46(6):462-470. Epub 26 Apr 2016. doi:10.2519/jospt.2016.6402.

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…

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.

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.

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.

Machine learning enhanced optical distance sensor

Science.gov (United States)

Amin, M. Junaid; Riza, N. A.

2018-01-01

Presented for the first time is a machine learning enhanced optical distance sensor. The distance sensor is based on our previously demonstrated distance measurement technique that uses an Electronically Controlled Variable Focus Lens (ECVFL) with a laser source to illuminate a target plane with a controlled optical beam spot. This spot with varying spot sizes is viewed by an off-axis camera and the spot size data is processed to compute the distance. In particular, proposed and demonstrated in this paper is the use of a regularized polynomial regression based supervised machine learning algorithm to enhance the accuracy of the operational sensor. The algorithm uses the acquired features and corresponding labels that are the actual target distance values to train a machine learning model. The optimized training model is trained over a 1000 mm (or 1 m) experimental target distance range. Using the machine learning algorithm produces a training set and testing set distance measurement errors of learning. Applications for the proposed sensor include industrial scenario distance sensing where target material specific training models can be generated to realize low <1% measurement error distance measurements.

Hydration status in adolescent runners: pre and post training