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Sample records for repeated-sprint ability rsa

  1. Development of Repeated Sprint Ability in Talented Youth Basketball Players

    NARCIS (Netherlands)

    te Wierike, Sanne C. M.; de Jong, Mark C.; Tromp, Eveline J. Y.; Vuijk, Pieter J.; Lemmink, Koen A. P. M.; Malina, Robert M.; Elferink-Gemser, Marije T.; Visscher, Chris

    te Wierike, SCM, de Jong, MC, Tromp, EJY, Vuijk, PJ, Lemmink, KAPM, Malina, RM, Elferink-Gemser, MT, and Visscher, C. Development of repeated sprint ability in talented youth basketball players. J Strength Cond Res 28(4): 928-934, 2014-Factors affecting repeated sprint ability (RSA) were evaluated

  2. Development of Repeated Sprint Ability in Talented Youth Basketball Players

    NARCIS (Netherlands)

    te Wierike, Sanne C. M.; de Jong, Mark C.; Tromp, Eveline J. Y.; Vuijk, Pieter J.; Lemmink, Koen A. P. M.; Malina, Robert M.; Elferink-Gemser, Marije T.; Visscher, Chris

    2014-01-01

    te Wierike, SCM, de Jong, MC, Tromp, EJY, Vuijk, PJ, Lemmink, KAPM, Malina, RM, Elferink-Gemser, MT, and Visscher, C. Development of repeated sprint ability in talented youth basketball players. J Strength Cond Res 28(4): 928-934, 2014-Factors affecting repeated sprint ability (RSA) were evaluated i

  3. Development of Repeated Sprint Ability in Talented Youth Basketball Players

    NARCIS (Netherlands)

    te Wierike, Sanne C. M.; de Jong, Mark C.; Tromp, Eveline J. Y.; Vuijk, Pieter J.; Lemmink, Koen A. P. M.; Malina, Robert M.; Elferink-Gemser, Marije T.; Visscher, Chris

    2014-01-01

    te Wierike, SCM, de Jong, MC, Tromp, EJY, Vuijk, PJ, Lemmink, KAPM, Malina, RM, Elferink-Gemser, MT, and Visscher, C. Development of repeated sprint ability in talented youth basketball players. J Strength Cond Res 28(4): 928-934, 2014-Factors affecting repeated sprint ability (RSA) were evaluated i

  4. Repeated-sprint ability and aerobic fitness.

    Science.gov (United States)

    Thébault, Nicolas; Léger, Luc A; Passelergue, Philippe

    2011-10-01

    The purpose of this study was to reinvestigate the relationship between aerobic fitness and fatigue indices of repeated-sprint ability (RSA), with special attention to methodological normalization. Soldiers were divided into low (n = 10) and high (n = 9) fitness groups according to a preset maximal aerobic speed (MAS) of 17 km·h(-1) (∼60 ml O2·kg(-1)·min) measured with the University of Montreal Track Test (UMTT). Subjects' assessment included the RSA test (3 sets of 5 40-m sprints with 1-minute rest between sprints and 1.5 minutes between sets), a 40-m sprint (criterion test used in the computation of fatigue indices for the RSA test), strength and power measurement of the lower limbs, and the 20-m shuttle run test (20-m SRT) and the UMTT, which are measures of maximal aerobic power. The highest correlation with the RSA fatigue indices was obtained with the 20-m SRT (r = 0.90, p = 0.0001, n = 19), a test with 180° direction changes and accelerations and decelerations. The lower correlation (r = 0.66, p repeated sprints and achieved better recovery between series. A MAS of at least 17 km·h(-1) favors constant and high speed level during repeated sprints. From a practical point of view, a high aerobic fitness is a precious asset in counteracting fatigue in sports with numerous sprint repetitions.

  5. Evolution of Determinant Factors of Repeated Sprint Ability.

    Science.gov (United States)

    Pareja-Blanco, Fernando; Suarez-Arrones, Luis; Rodríguez-Rosell, David; López-Segovia, Manuel; Jiménez-Reyes, Pedro; Bachero-Mena, Beatriz; González-Badillo, Juan José

    2016-12-01

    The aim of this study was to investigate the changes in the relationships between repeated sprint ability (RSA) and anthropometric measures as well as fitness qualities in soccer players. Twenty-one professional soccer players performed several anthropometric and physical tests including countermovement vertical jumps (CMJs), a straight-line 30 m sprint (T30), an RSA test (6 x 20 + 20 m with 20 s recovery), a progressive isoinertial loading test in a full squat, a Yo-Yo Intermittent Recovery Test Level-1 (YYIRT-1) and a 20 m shuttle run test (20mSRT). The mean (RSAmean), the fastest (RSAbest), each single sprint time, and the percentage in a sprint decrease (%Dec) in the RSA test were calculated. RSAbest correlated significantly with RSAmean (r = .82) and with all single sprints (p sprints performed increased. No significant relationship was observed between the %Dec and RSA performance. CMJs and the T30 also showed a correlation with RSA performance, whereas lower limb strength did not show any relationship with RSA performance. RSAmean showed significant (p repeated sprints increased. The 20mSRT showed minimal relationships with RSA performance. In conclusion, maximal sprint capacity seems to be relevant for the RSA performance, mainly in the first sprints. However, high intermittent endurance capacity and low adiposity might help enhance the RSA performance when increasing the number of repeated sprints.

  6. Repeated-sprint and effort ability in rugby league players.

    Science.gov (United States)

    Johnston, Rich D; Gabbett, Tim J

    2011-10-01

    The aim of this study was to (a) investigate the influence of tackling on repeated-sprint performance; (b) determine whether repeated-sprint ability (RSA) and repeated-effort ability (REA) are 2 distinct qualities; and (c) assess the test-retest reliability of repeated-sprint and repeated-effort tests in rugby league. Twelve rugby league players performed a repeated-sprint (12 × 20-m sprints performed on a 20-second cycle) and a repeated-effort (12 × 20-m sprints with intermittent tackling, performed on a 20-second cycle) test 7 days apart. The test-retest reliability of these tests was also established. Heart rate and rating of perceived exertion were recorded throughout the tests. There was a significantly greater (p ≤ 0.05) and large effect size (ES) differences for total sprint time (ES = 1.19), average heart rate (ES = 1.64), peak heart rate (ES = 1.35), and perceived exertion (ES = 3.39) for the repeated-effort test compared with the repeated-sprint test. A large difference (ES = 1.02, p = 0.06) was detected for percentage decrement between the 2 tests. No significant relationship was found between the repeated-sprint and repeated-effort tests for any of the dependent variables. Both tests proved reliable, with total sprint time being the most reliable method of assessing performance. This study demonstrates that the addition of tackling significantly increases the physiological response to repeated-sprint exercise and reduces repeated-sprint performance in rugby league players. Furthermore, RSA and REA appear to be 2 distinct qualities that can be reliably assessed with total time being the most reliable measure of performance.

  7. Development of repeated sprint ability in talented youth basketball players.

    NARCIS (Netherlands)

    Wierike, S.C. te; Jong, M.C. de; Tromp, E.J.; Vuijk, P.J.; Lemmink, K.A.; Malina, R.M.; Elferink-Gemser, M.T.; Visscher, C.

    2013-01-01

    Factors affecting repeated sprint ability (RSA) were evaluated in a mixed-longitudinal sample of 48 elite basketball players 14 to 19 years of age (16.1±1.7 years). Players were observed on six occasions during the 2008-2009 and 2009-2010 seasons. Three basketball-specific field tests were administe

  8. Development of repeated sprint ability in talented youth basketball players.

    NARCIS (Netherlands)

    Koen A.P.M. Lemmink; S.C. te Wierike; E.J. Tromp; M.T. Elferink-Gemser; M.C. de Jong; R.M. Malina; P.J. Vuijk; C. Visscher

    2013-01-01

    Factors affecting repeated sprint ability (RSA) were evaluated in a mixed-longitudinal sample of 48 elite basketball players 14 to 19 years of age (16.1±1.7 years). Players were observed on six occasions during the 2008-2009 and 2009-2010 seasons. Three basketball-specific field tests were

  9. Development of repeated sprint ability in talented youth basketball players.

    NARCIS (Netherlands)

    Koen A.P.M. Lemmink; S.C. te Wierike; E.J. Tromp; M.T. Elferink-Gemser; M.C. de Jong; R.M. Malina; P.J. Vuijk; C. Visscher

    2013-01-01

    Factors affecting repeated sprint ability (RSA) were evaluated in a mixed-longitudinal sample of 48 elite basketball players 14 to 19 years of age (16.1±1.7 years). Players were observed on six occasions during the 2008-2009 and 2009-2010 seasons. Three basketball-specific field tests were administe

  10. Evolution of Determinant Factors of Repeated Sprint Ability

    Directory of Open Access Journals (Sweden)

    Pareja-Blanco Fernando

    2016-12-01

    Full Text Available The aim of this study was to investigate the changes in the relationships between repeated sprint ability (RSA and anthropometric measures as well as fitness qualities in soccer players. Twenty-one professional soccer players performed several anthropometric and physical tests including countermovement vertical jumps (CMJs, a straight-line 30 m sprint (T30, an RSA test (6 x 20 + 20 m with 20 s recovery, a progressive isoinertial loading test in a full squat, a Yo-Yo Intermittent Recovery Test Level-1 (YYIRT-1 and a 20 m shuttle run test (20mSRT. The mean (RSAmean, the fastest (RSAbest, each single sprint time, and the percentage in a sprint decrease (%Dec in the RSA test were calculated. RSAbest correlated significantly with RSAmean (r = .82 and with all single sprints (p < 0.05, showing a downward trend as the number of sprints performed increased. No significant relationship was observed between the %Dec and RSA performance. CMJs and the T30 also showed a correlation with RSA performance, whereas lower limb strength did not show any relationship with RSA performance. RSAmean showed significant (p < 0.05 relationships with body mass (r = .44, adiposity (r = .59 and the YYIRT-1 (r = -.62, increasing as the number of repeated sprints increased. The 20mSRT showed minimal relationships with RSA performance. In conclusion, maximal sprint capacity seems to be relevant for the RSA performance, mainly in the first sprints. However, high intermittent endurance capacity and low adiposity might help enhance the RSA performance when increasing the number of repeated sprints.

  11. Repeated-sprint ability - part II: recommendations for training.

    Science.gov (United States)

    Bishop, David; Girard, Olivier; Mendez-Villanueva, Alberto

    2011-09-01

    Short-duration sprints, interspersed with brief recoveries, are common during most team sports. The ability to produce the best possible average sprint performance over a series of sprints (≤10 seconds), separated by short (≤60 seconds) recovery periods has been termed repeated-sprint ability (RSA). RSA is therefore an important fitness requirement of team-sport athletes, and it is important to better understand training strategies that can improve this fitness component. Surprisingly, however, there has been little research about the best training methods to improve RSA. In the absence of strong scientific evidence, two principal training theories have emerged. One is based on the concept of training specificity and maintains that the best way to train RSA is to perform repeated sprints. The second proposes that training interventions that target the main factors limiting RSA may be a more effective approach. The aim of this review (Part II) is to critically analyse training strategies to improve both RSA and the underlying factors responsible for fatigue during repeated sprints (see Part I of the preceding companion article). This review has highlighted that there is not one type of training that can be recommended to best improve RSA and all of the factors believed to be responsible for performance decrements during repeated-sprint tasks. This is not surprising, as RSA is a complex fitness component that depends on both metabolic (e.g. oxidative capacity, phosphocreatine recovery and H+ buffering) and neural factors (e.g. muscle activation and recruitment strategies) among others. While different training strategies can be used in order to improve each of these potential limiting factors, and in turn RSA, two key recommendations emerge from this review; it is important to include (i) some training to improve single-sprint performance (e.g. 'traditional' sprint training and strength/power training); and (ii) some high-intensity (80-90% maximal oxygen

  12. The validity and reliability of a global positioning satellite system device to assess speed and repeated sprint ability (RSA) in athletes.

    Science.gov (United States)

    Barbero-Alvarez, José C; Coutts, Aaron; Granda, Juan; Barbero-Alvarez, Verónica; Castagna, Carlo

    2010-03-01

    There is a limited understanding of the validity and reliability of commercially available global positioning satellite (GPS) devices for assessing repeated sprint performance in athletes. The aims of this study were to assess the convergent validity and the test-retest reliability of a GPS device for measuring repeated sprint ability test (RSAT) variables. Two groups participated in this study, a group of 21 physical education students (age: 20.2+/-2.3 years, stature: 1.75+/-0.42 m, body mass: 68.0+/-6.8kg) and a second group 14 elite junior soccer players (age: 14.5+/-1.2 years, stature: 1.60+/-0.09 m, body mass: 57.7+/-3.8kg) volunteered to participate in this study. Convergent validity was assessed as the correlation between sprint performance (15 and 30-m) using both timing lights and a portable GPS device during a RSAT (7 x 30-m sprints with 30-s of active recovery). The 7 x 30-m RSAT test-retest reliability using GPS device was assessed in elite junior soccer players repeating the test 1 week apart and expressing reliability as a coefficient of variation. Results showed a strong correlation between peak speed measures with the GPS device and RSAT performance measured with timing lights for the 15-m (r(2)=0.87, pspeed (1.7%) and peak speed (1.2%) during the 7 x 30-m RSAT, but high variation for the percentage decrement score (36.2%). These results provide evidence to support the use of the GPS device as an alternative measure to assess repeated sprint performance but suggest a percentage decrement score is not a reliable measure of RSAT performance.

  13. No Additional Benefit of Repeat-Sprint Training in Hypoxia than in Normoxia on Sea-Level Repeat-Sprint Ability

    Science.gov (United States)

    Goods, Paul S.R.; Dawson, Brian; Landers, Grant J.; Gore, Christopher J.; Peeling, Peter

    2015-01-01

    To assess the impact of ‘top-up’ normoxic or hypoxic repeat-sprint training on sea-level repeat-sprint ability, thirty team sport athletes were randomly split into three groups, which were matched in running repeat-sprint ability (RSA), cycling RSA and 20 m shuttle run performance. Two groups then performed 15 maximal cycling repeat-sprint training sessions over 5 weeks, in either normoxia (NORM) or hypoxia (HYP), while a third group acted as a control (CON). In the post-training cycling RSA test, both NORM (13.6%; p = 0.0001, and 8.6%; p = 0.001) and HYP (10.3%; p = 0.007, and 4.7%; p = 0.046) significantly improved overall mean and peak power output, respectively, whereas CON did not change (1.4%; p = 0.528, and -1.1%; p = 0.571, respectively); with only NORM demonstrating a moderate effect for improved mean and peak power output compared to CON. Running RSA demonstrated no significant between group differences; however, the mean sprint times improved significantly from pre- to post-training for CON (1.1%), NORM (1.8%), and HYP (2.3%). Finally, there were no group differences in 20 m shuttle run performance. In conclusion, ‘top-up’ training improved performance in a task-specific activity (i.e. cycling); however, there was no additional benefit of conducting this ‘top-up’ training in hypoxia, since cycle RSA improved similarly in both HYP and NORM conditions. Regardless, the ‘top-up’ training had no significant impact on running RSA, therefore the use of cycle repeat-sprint training should be discouraged for team sport athletes due to limitations in specificity. Key points ‘Top-up’ repeat-sprint training performed on a cycle ergometer enhances cycle repeat-sprint ability compared to team sport training only in football players. The addition of moderate hypoxia to repeat-sprint training provides no additional performance benefits to sea-level repeat-sprint ability or endurance performance than normoxic repeat-sprint training.

  14. No Additional Benefit of Repeat-Sprint Training in Hypoxia than in Normoxia on Sea-Level Repeat-Sprint Ability.

    Science.gov (United States)

    Goods, Paul S R; Dawson, Brian; Landers, Grant J; Gore, Christopher J; Peeling, Peter

    2015-09-01

    To assess the impact of 'top-up' normoxic or hypoxic repeat-sprint training on sea-level repeat-sprint ability, thirty team sport athletes were randomly split into three groups, which were matched in running repeat-sprint ability (RSA), cycling RSA and 20 m shuttle run performance. Two groups then performed 15 maximal cycling repeat-sprint training sessions over 5 weeks, in either normoxia (NORM) or hypoxia (HYP), while a third group acted as a control (CON). In the post-training cycling RSA test, both NORM (13.6%; p = 0.0001, and 8.6%; p = 0.001) and HYP (10.3%; p = 0.007, and 4.7%; p = 0.046) significantly improved overall mean and peak power output, respectively, whereas CON did not change (1.4%; p = 0.528, and -1.1%; p = 0.571, respectively); with only NORM demonstrating a moderate effect for improved mean and peak power output compared to CON. Running RSA demonstrated no significant between group differences; however, the mean sprint times improved significantly from pre- to post-training for CON (1.1%), NORM (1.8%), and HYP (2.3%). Finally, there were no group differences in 20 m shuttle run performance. In conclusion, 'top-up' training improved performance in a task-specific activity (i.e. cycling); however, there was no additional benefit of conducting this 'top-up' training in hypoxia, since cycle RSA improved similarly in both HYP and NORM conditions. Regardless, the 'top-up' training had no significant impact on running RSA, therefore the use of cycle repeat-sprint training should be discouraged for team sport athletes due to limitations in specificity. Key points'Top-up' repeat-sprint training performed on a cycle ergometer enhances cycle repeat-sprint ability compared to team sport training only in football players.The addition of moderate hypoxia to repeat-sprint training provides no additional performance benefits to sea-level repeat-sprint ability or endurance performance than normoxic repeat-sprint training.'Top-up' cycling repeat-sprint training

  15. Development of repeated sprint ability in talented youth basketball players.

    Science.gov (United States)

    te Wierike, Sanne C M; de Jong, Mark C; Tromp, Eveline J Y; Vuijk, Pieter J; Lemmink, Koen A P M; Malina, Robert M; Elferink-Gemser, Marije T; Visscher, Chris

    2014-04-01

    Factors affecting repeated sprint ability (RSA) were evaluated in a mixed-longitudinal sample of 48 elite basketball players 14-19 years of age (16.1 ± 1.7 years). Players were observed on 6 occasions during the 2008-09 and 2009-10 seasons. Three following basketball-specific field tests were administered on each occasion: the shuttle sprint test for RSA, the vertical jump for lower body explosive strength (power), and the interval shuttle run test for interval endurance capacity. Height and weight were measured; body composition was estimated (percent fat, lean body mass). Multilevel modeling of RSA development curve was used with 32 players (16.0 ± 1.7 years) who had 2 or more observations. The 16 players (16.1 ± 1.8 years) measured on only 1 occasion were used as a control group to evaluate the appropriateness of the model. Age, lower body explosive strength, and interval endurance capacity significantly contributed to RSA (p ≤ 0.05). Repeated sprint ability improved with age from 14 to 17 years (p ≤ 0.05) and reached a plateau at 17-19 years. Predicted RSA did not significantly differ from measured RSA in the control group (p ≥ 0.05). The results suggest a potentially important role for the training of lower body explosive strength and interval endurance capacity in the development of RSA among youth basketball players. Age-specific reference values for RSA of youth players may assist basketball coaches in setting appropriate goals for individual players.

  16. Aerobic Capacity is Related to Repeated Sprint Ability with Sprint Distances Less Than 40 Meters.

    Science.gov (United States)

    Sanders, Gabriel J; Turner, Zachary; Boos, Brian; Peacock, Corey A; Peveler, Willard; Lipping, Alar

    2017-01-01

    Research is inconclusive regarding the association between aerobic fitness (objectively measured VO2max) and repeated sprint performance when the sprints are less than 40 meters. Soccer athletes must be able to repeat sprints without significant decreases in speed and strength and conditioning coaches need to better understand if aerobic fitness is related to repeated sprint ability (RSA). Twenty (10 male, 10 female) Division I soccer athletes first completed a graded maximal treadmill test to measure VO2max. Then on a separate day, athletes completed the RSA test. The RSA test consisted of 10, 30-meter sprints which athletes repeated every 30 seconds. There were significant negative correlations (r ≤ -0.69, P sprint times and average sprint time. More aerobically fit Division I soccer athletes were faster at all time points during the RSA test. Aerobic fitness is associated with faster sprint times during a more anaerobic RSA test when sprint distances are less than 40 meters.

  17. Repeated sprint ability in young basketball players: one vs. two changes of direction (Part 2).

    Science.gov (United States)

    Attene, Giuseppe; Laffaye, Guillaume; Chaouachi, Anis; Pizzolato, Fabio; Migliaccio, Gian Mario; Padulo, Johnny

    2015-01-01

    The aim of this study was to compare the training effects based on repeated sprint ability (RSA) (with one change of direction) with an intensive repeated sprint ability (IRSA) (with two changes of direction) on jump performance and aerobic fitness. Eighteen male basketball players were assigned to repeated sprint ability and intensive repeated sprint ability training groups (RSAG and IRSAG). RSA, IRSA, squat jump (SJ), countermovement jump (CMJ) and Yo-Yo intermittent recovery level 1 test were assessed before and after four training weeks. The RSA and IRSA trainings consisted of three sets of six sprints (first two weeks) and eight sprints (second two weeks) with 4-min sets recovery and 20-s of sprints recovery. Four weeks of training led to an overall improvement in most of the measures of RSA, but little evidence of any differences between the two training modes. Jump performance was enhanced: CMJ of 7.5% (P repeated sprint training with one/two changes of direction promotes improvements in both RSA and IRSA respectively but the better increase on jump performance shown a few changes on sprint and endurance performances.

  18. Repeated-sprint ability - part I: factors contributing to fatigue.

    Science.gov (United States)

    Girard, Olivier; Mendez-Villanueva, Alberto; Bishop, David

    2011-08-01

    Short-duration sprints (ability to recover and to reproduce performance in subsequent sprints is probably an important fitness requirement of athletes engaged in these disciplines, and has been termed repeated-sprint ability (RSA). This review (Part I) examines how fatigue manifests during repeated-sprint exercise (RSE), and discusses the potential underpinning muscular and neural mechanisms. A subsequent companion review to this article will explain a better understanding of the training interventions that could eventually improve RSA. Using laboratory and field-based protocols, performance analyses have consistently shown that fatigue during RSE typically manifests as a decline in maximal/mean sprint speed (i.e. running) or a decrease in peak power or total work (i.e. cycling) over sprint repetitions. A consistent result among these studies is that performance decrements (i.e. fatigue) during successive bouts are inversely correlated to initial sprint performance. To date, there is no doubt that the details of the task (e.g. changes in the nature of the work/recovery bouts) alter the time course/magnitude of fatigue development during RSE (i.e. task dependency) and potentially the contribution of the underlying mechanisms. At the muscle level, limitations in energy supply, which include energy available from phosphocreatine hydrolysis, anaerobic glycolysis and oxidative metabolism, and the intramuscular accumulation of metabolic by-products, such as hydrogen ions, emerge as key factors responsible for fatigue. Although not as extensively studied, the use of surface electromyography techniques has revealed that failure to fully activate the contracting musculature and/or changes in inter-muscle recruitment strategies (i.e. neural factors) are also associated with fatigue outcomes. Pending confirmatory research, other factors such as stiffness regulation, hypoglycaemia, muscle damage and hostile environments (e.g. heat, hypoxia) are also likely to compromise

  19. Intermittent endurance and repeated sprint ability in soccer players.

    Science.gov (United States)

    Chaouachi, Anis; Manzi, Vincenzo; Wong, Del P; Chaalali, Anis; Laurencelle, Louis; Chamari, Karim; Castagna, Carlo

    2010-10-01

    The ability to perform high-intensity intermittent exercise (i.e., Yo-Yo Intermittent Recovery Test [Yo-Yo IR1]) and to repeat sprints with relatively short recovery times (i.e., 20- to 30-seconds, relatively short time interval [repeated sprint ability (RSA)]) has been shown to be relevant fitness variables in soccer. However, though they potentially share common features, it is not known whether these 2 abilities are associated. The aim of this study was to examine the relationships between Yo-Yo IR1 and RSA performances in elite soccer players. Twenty-three soccer players (age 19 ± 1 years, height 181 ± 5.7 cm, body mass 73.2 ± 4.1 kg, %body fat 11 ± 2.4) performed the Yo-Yo IR1 and a test for RSA (7 × 30 m with 25-second recovery). Results were 2,289 ± 409 m, 31.21 ± 1.13 seconds, and 4 ± 2.1% for Yo-Yo IR1, total sprint time, and sprint decrement, respectively. Yo-Yo IR1 showed a significant and moderate relationship with sprint decrement (r² = -0.44, p = 0.04). Splitting the sample into Best and Worst Yo-Yo IR1 performers according to median score (2,320 m), the Best group showed lower RSA total time (30.69 ± 0.99 vs. 31.79 ± 1.06, p Sprint-time deterioration over 30 m occurred earlier (from the second sprint on) in the Yo-YoWorst compared with in the Yo-YoBest group (from the fourth sprint on, p sprint bouts.

  20. Aerobic Capacity is Related to Repeated Sprint Ability with Sprint Distances Less Than 40 Meters

    Science.gov (United States)

    SANDERS, GABRIEL J.; TURNER, ZACHARY; BOOS, BRIAN; PEACOCK, COREY A.; PEVELER, WILLARD; LIPPING, ALAR

    2017-01-01

    Research is inconclusive regarding the association between aerobic fitness (objectively measured VO2max) and repeated sprint performance when the sprints are less than 40 meters. Soccer athletes must be able to repeat sprints without significant decreases in speed and strength and conditioning coaches need to better understand if aerobic fitness is related to repeated sprint ability (RSA). Twenty (10 male, 10 female) Division I soccer athletes first completed a graded maximal treadmill test to measure VO2max. Then on a separate day, athletes completed the RSA test. The RSA test consisted of 10, 30-meter sprints which athletes repeated every 30 seconds. There were significant negative correlations (r ≤ −0.69, P distances are less than 40 meters.

  1. Relationship between Repeated Sprint Ability and Aerobic Capacity in Professional Soccer Players

    Directory of Open Access Journals (Sweden)

    Rhys M. Jones

    2013-01-01

    Full Text Available Aim. The aim of the present study was to investigate the relationship between maximal aerobic capacity ( and repeated sprint ability (RSA in a group of professional soccer players. Methods. Forty-one professional soccer players (age  yrs, height  cm, weight  kg were required to perform tests to assess RSA and on two separate days with at least 48 hr rest between testing sessions. Each player performed a treadmill test to determine their and a test for RSA involving the players completing  m sprints (turn after 20 m with 20 s active recovery between each sprint. Results. There was a significant negative correlation between body mass normalised and mean sprint time ( (; and total sprint time ( (, . Conclusion. Results of the current study indicate that is one important factor aiding soccer players in the recovery from repeated sprint type activities.

  2. Sympathetic enhancement in futsal players but not in football players after repeated sprint ability test

    OpenAIRE

    Chen, Yung-Sheng; Liao, Chih-Jung; Lu, Wan-An; Kuo, Cheng-Deng

    2015-01-01

    Background Heart rate variability (HRV) can disclose the specific adaptation of sympathovagal modulation to exercise. This study investigated the change in HRV measures after anaerobic and aerobic intermittent exercises in university football and futsal players. Method 36 male university students with physically active lifestyle (n=14), football (n=12), and futsal (n=10) participated in this study. The participants completed the repeated sprint ability (RSA) test and Yo-Yo (YY) intermittent r...

  3. Repeated sprint ability in young basketball players: one vs. two changes of direction (Part 1).

    Science.gov (United States)

    Padulo, Johnny; Laffaye, Guillaume; Haddad, Monoem; Chaouachi, Anis; Attene, Giuseppe; Migliaccio, Gian Mario; Chamari, Karim; Pizzolato, Fabio

    2015-01-01

    The present study aimed to compare the changes of direction on repeated sprint ability (RSA) vs. intensive repeated sprint ability (IRSA) protocols in basketball. Eighteen young male basketball players performed on RSA [10 × 30-m (15 + 15-m, one change of direction)] and IRSA [10 × 30-m (10 + 10 + 10-m, two changes of direction)]. A correlation matrix between RSA, IRSA, "squat jump (SJ)-countermovement jump (CMJ)", footstep analysis and total distance in Yo-Yo intermittent recovery level 1 was performed. The best time, worst time, total time and the number of footsteps were significantly smaller in the RSA test compared to IRSA test (P  0.80, P  0.478, P  0.515, P  0.489, P basketball game's actions (~2 s). Besides, IRSA could be an appropriate choice for assessing both RSA and changes of direction capacities in basketball players.

  4. The relationship between repeated sprint ability and the aerobic and anaerobic energy systems.

    Science.gov (United States)

    Wadley, G; Le Rossignol, P

    1998-06-01

    A large number of team games require participants to repeatedly produce maximal or near maximal sprints of short duration with brief recovery periods. The purpose of the present study was to determine the relationship between a repeated sprint ability (RSA) test that is specific to the energy demands of Australian Rules football (ARF), and the aerobic and anaerobic energy systems. Seventeen ARF players participated in the study. Each participant was assessed for VO2 max, accumulated oxygen deficit (AOD), best 20 m sprint time and RSA. The RSA test involved 12x20 m sprints departing every 20 s. When including the work performed during the time taken to decelerate, the test involved a work to rest ratio of approximately 1:3. Total sprinting time and the percentage decrement of repeated sprinting times were the two derived measures of RSA. The results indicate that the best 20 m sprint time was the only factor to correlate significantly with total sprinting time (r = 0.829, P RSA test. This was interpreted to signify that the phosphagen system was the major energy contributor for this test.

  5. Modelling Developmental Changes in Repeated-Sprint Ability by Chronological and Skeletal Ages in Young Soccer Players

    NARCIS (Netherlands)

    Valente-dos-Santos, J.; Coelho-e-Silva, M. J.; Martins, R. A.; Figueiredo, A. J.; Cyrino, E. S.; Sherar, L. B.; Vaeyens, R.; Huijgen, B. C. H.; Elferink-Gemser, M. T.; Malina, R. M.

    2012-01-01

    This study investigated the influence of chronological (CA) and skeletal ages (SA), anthropometry, aerobic endurance and lower limb explosive strength on developmental changes in repeated-sprint ability (RSA) in soccer players aged 11-17 years. Participants were annually followed over 5 years, resul

  6. Modelling Developmental Changes in Repeated-Sprint Ability by Chronological and Skeletal Ages in Young Soccer Players

    NARCIS (Netherlands)

    Valente-dos-Santos, J.; Coelho-e-Silva, M. J.; Martins, R. A.; Figueiredo, A. J.; Cyrino, E. S.; Sherar, L. B.; Vaeyens, R.; Huijgen, B. C. H.; Elferink-Gemser, M. T.; Malina, R. M.

    2012-01-01

    This study investigated the influence of chronological (CA) and skeletal ages (SA), anthropometry, aerobic endurance and lower limb explosive strength on developmental changes in repeated-sprint ability (RSA) in soccer players aged 11-17 years. Participants were annually followed over 5 years, resul

  7. Modelling Developmental Changes in Repeated-Sprint Ability by Chronological and Skeletal Ages in Young Soccer Players

    NARCIS (Netherlands)

    Valente-dos-Santos, J.; Coelho-e-Silva, M. J.; Martins, R. A.; Figueiredo, A. J.; Cyrino, E. S.; Sherar, L. B.; Vaeyens, R.; Huijgen, B. C. H.; Elferink-Gemser, M. T.; Malina, R. M.

    2012-01-01

    This study investigated the influence of chronological (CA) and skeletal ages (SA), anthropometry, aerobic endurance and lower limb explosive strength on developmental changes in repeated-sprint ability (RSA) in soccer players aged 11-17 years. Participants were annually followed over 5 years,

  8. Correlation between explosive strength, aerobic power and repeated sprint ability in elite basketball players.

    Science.gov (United States)

    Stojanovic, M D; Ostojic, S M; Calleja-González, J; Milosevic, Z; Mikic, M

    2012-08-01

    The aim of this study was to examine the relationship between explosive strength and aerobic power with basketball-specific repeated sprint ability in elite male basketball players. Twenty-four elite basketball players (age 22.2±3.4 years, height 197.1±6.2 cm, weight 95.7±8.8 kg; training experience 11.0±3.1 years; mean±SD), participated in the study. Subjects performed countermovement jump (CMJ) test and incremental pseudo-ramp test protocol with measured CMJ height and VO2max, respectively. Specific repeated sprint ability (RSA) test was conducted, with total sprinting time (summation of 10 sprint times - RSAtot) and sprint decrement (fatigue index - RSAFI) calculated. Significant decrements in sprint performance from the eight 30-m sprint (P<0.05) were observed. Strong inverse correlation was found between CMJ and RSAtot (r=-0.74, P<0.01). No significant correlation was found between VO2max and RSA outcomes neither between CMJ and RSAFI. CMJ is a predictor of RSA in elite basketball players. It seems that coaches and strength and conditioning professionals should devote additional time for explosive strength development in elite basketball players during preparatory period to enhance RSA performance.

  9. Relationship between repeated sprint ability and aerobic capacity in professional soccer players.

    Science.gov (United States)

    Jones, Rhys M; Cook, Christian C; Kilduff, Liam P; Milanović, Zoran; James, Nic; Sporiš, Goran; Fiorentini, Bruno; Fiorentini, Fredi; Turner, Anthony; Vučković, Goran

    2013-01-01

    The aim of the present study was to investigate the relationship between maximal aerobic capacity (VO(2max)) and repeated sprint ability (RSA) in a group of professional soccer players. Forty-one professional soccer players (age 23 ± 4 yrs, height 180.0 ± 5.3 cm, weight 79.6 ± 5.3 kg) were required to perform tests to assess RSA and VO(2max) on two separate days with at least 48 hr rest between testing sessions. Each player performed a treadmill test to determine their VO(2max) and a test for RSA involving the players completing 6 × 40 m sprints (turn after 20 m) with 20 s active recovery between each sprint. There was a significant negative correlation between body mass normalised VO(2max) and mean sprint time (RSAmean) (r = -0.655; P sprint time (RSAtotal) (r = -0.591, P repeated sprint type activities.

  10. Relationship between Repeated Sprint Ability and Aerobic Capacity in Professional Soccer Players

    Science.gov (United States)

    Jones, Rhys M.; Cook, Christian C.; Kilduff, Liam P.; Milanović, Zoran; James, Nic; Sporiš, Goran; Fiorentini, Bruno; Fiorentini, Fredi; Turner, Anthony; Vučković, Goran

    2013-01-01

    Aim. The aim of the present study was to investigate the relationship between maximal aerobic capacity (VO2 max) and repeated sprint ability (RSA) in a group of professional soccer players. Methods. Forty-one professional soccer players (age 23 ± 4 yrs, height 180.0 ± 5.3 cm, weight 79.6 ± 5.3 kg) were required to perform tests to assess RSA and VO2 max on two separate days with at least 48 hr rest between testing sessions. Each player performed a treadmill test to determine their VO2 max and a test for RSA involving the players completing 6 × 40 m sprints (turn after 20 m) with 20 s active recovery between each sprint. Results. There was a significant negative correlation between body mass normalised VO2 max and mean sprint time (RSAmean) (r = −0.655; P < 0.01) and total sprint time (RSAtotal) (r = −0.591, P < 0.01). Conclusion. Results of the current study indicate that VO2 max is one important factor aiding soccer players in the recovery from repeated sprint type activities. PMID:24198732

  11. Time of day effects on repeated sprint ability.

    Science.gov (United States)

    Zarrouk, N; Chtourou, H; Rebai, H; Hammouda, O; Souissi, N; Dogui, M; Hug, F

    2012-12-01

    The present study aimed at investigating the effects of time-of-day on muscle power and associated electromyographic (EMG) activity level of 4 thigh muscles during a repeated pedalling sprint exercise. After a familiarization session, 12 male subjects were asked to perform the repeated sprint ability test during 2 experimental sessions (randomized order), which were set up either at 06:00 or 18:00 h. For each sprint, peak power output, percentage of peak power decrement and total work were calculated. EMG activity of vastus lateralis, rectus femoris, vastus medialis and biceps femoris muscles was recorded throughout the test and analyzed for each sprint. Total work and percentage of peak power decrement were higher in the evening than in the morning (psprints (psprint 1 and psprint 2 and 3). There was no time-of-day effect for EMG activity level. The neuromuscular efficiency decreased significantly over the repeated sprint ability test at the 2 times of testing (prepeated sprint ability test, EMG activity of major thigh muscles was not time-of-day dependent. © Georg Thieme Verlag KG Stuttgart · New York.

  12. REPEATED SPRINT ABILITY AND RECOVERY PERIOD: COMPARISON OF TRAINED AND UNTRAINED INDIVIDUALS

    Directory of Open Access Journals (Sweden)

    Sultan

    2016-04-01

    Full Text Available The purpose of the study was to investigate the effects of training both in repeated sprint ability (RSA and during the recovery after sprint. Soccer players playing in regional amateur league (n=14, age: 21.86±2.35 years, height: 180.14±4.54 cm, body mass: 72.57±5.03 kg, training age: 8.71±1.86 years and students from faculty of sport sciences that played soccer in the past (n=13, age: 23.77±2.65 years, height: 178.54±4.67 cm, body mass: 74.54±10.52 kg participated in this study as trained and untrained group, respectively. The groups were tested using Yo-Yo intermittent recovery test level 1 (YIRT1 and maximum oxygen uptake (VO2max was calculated using a formula from distance covered in YIRT1. Groups performed a repeated sprint ability (RSA, 6x6 s of Wingate test protocol + 30 s of rest test after 48 h. Blood lactate level and heart rate of groups were recorded at rest, immediately, 5, 15, and 30 min after RSA test. The absolute peak power and relative mean power in repeated sprints and the VO2max values were significantly higher in trained group than in untrained group (p<0.05. The absolute values of mean power was also significantly higher in trained group compared to that of the untrained group, except for the first sprint (p<0.05. On the other hand, it was observed that blood lactate level at 30 min and heart rate at 15 and 30 min of the recovery after testing was significantly lower in trained group than those of untrained group (p<0.05. The performance and metabolic results showed that VO2max level would be effective both in maintaining repeated sprint ability performance and for the acceleration of the recovery period.

  13. Relationship among Repeated Sprint Ability, Chronological Age and Puberty in young soccer players.

    Science.gov (United States)

    Perroni, Fabrizio; Pintus, Antonio; Frandino, Mattia; Guidetti, Laura; Baldari, Carlo

    2016-01-20

    The aim of this study was to analyzed the relationship of Repeated Sprinting Ability (RSA) with chronological age and puberty in 100 young soccer players (Age: 13 ± 3 yr - 160 ± 33 month-; High: 159 ± 16 cm, Weight: 49.7 ± 14.1 kg; BMI 19.2 ± 2.5 kg/m) grouped on "Pulcini" (9 - 10 yrs), "Esordienti" (11 - 12 yrs), "Giovanissimi" (13 - 14 yrs), "Allievi" (15 - 16 yrs) and "Juniores" (> 17 yrs) categories. Anthropometric (Weight, Height, BMI), RSA (7x30 m sprint with 25s active rest: Total Time -TT, the lowest sprinting time (LST) and the fatigue index percentage -%IF), and Development (Self-Administered Rating Scale for pubertal development - PDS; Puberty) parameters were measured. ANOVA among categories was applied to asses differences (pinjury and overtraining during the different phases of growth and maturation.

  14. The relationship between short- and long-distance swimming performance and repeated sprint ability.

    Science.gov (United States)

    Meckel, Yoav; Bishop, David J; Rabinovich, Moran; Kaufman, Leonid; Nemet, Dan; Eliakim, Alon

    2012-12-01

    The purpose of this study was to determine indices of repeated sprint ability (RSA) during a repeated sprint swimming test (RST), to compare these with previous similar running and cycling RST, and to correlate these indices with the best short (100 m, as an index of anaerobic performance) and long (2,000 m, as an index of aerobic performance) distance swimming times in 20 elite, national team level, male swimmers. Indices of RSA included the ideal sprint time (IS), the total sprint time (TS), and the performance decrement (PD) recorded during an 8 × 15-m swimming RST. The PD during the present swimming RST (4.7 ± 2.3%) was similar to that in previous running or cycling RSTs. However, the physiological responses after the swimming RST (heart rate 168 ± 7 b·min(-1) and blood lactate concentration 5.5 ± 2.0 mmol·L(-1)) were lower than typical responses after running or cycling RSTs. There was no significant relationship between any of the RST performance indices and either the 100-m or 2,000-m swimming results. Multiple regression analysis indicated that the 3 RST indices (IS, TS, and PD), contributed 36% of the variance of the 2,000-m, but not the 100-m, swimming time. A strong correlation was found between the 100- and 2,000-m swim times (r = 0.74, p 100- and 2,000-m swim times is unique for swimming.

  15. Effects of sodium phosphate and beetroot juice supplementation on repeated-sprint ability in females.

    Science.gov (United States)

    Buck, Christopher L; Henry, Timothy; Guelfi, Kym; Dawson, Brian; McNaughton, Lars R; Wallman, Karen

    2015-10-01

    Sodium phosphate (SP) and beetroot juice (BJ) supplementation was assessed on repeated-sprint ability (RSA). Thirteen female team-sport participants completed four trials: (1) SP and BJ (SP + BJ), (2) SP and placebo (for BJ), (3) BJ and placebo (for SP) and (4) placebo (for SP + BJ), with ~21 days separating each trial. After each trial, participants performed a simulated team-game circuit (STGC) consisting of four 15 min quarters, with a 6 × 20-m repeated-sprint set performed at the start, half-time and end. Total sprint times were between 0.95-1.30 and 0.83-1.12 s faster for each RSA set and 3.25 and 3.12 s faster overall (~5% improvement) after SP compared with placebo and BJ, respectively (p = 0.02 for sets 1, 2 and overall; Cohen's effect size: d = -0.51 to -0.90 for all sets and overall). Additionally, total sprint times were 0.48 s faster after SP + BJ compared with placebo (set 2; p = 0.05, ~2% improvement). Furthermore, best sprints were 0.13-0.23 and 0.15-0.20 s faster (~6% improvement; p sprint times were faster after SP compared with placebo and BJ.

  16. Repeated sprint ability in young basketball players: multi-direction vs. one-change of direction (Part 1

    Directory of Open Access Journals (Sweden)

    Johnny ePadulo

    2016-04-01

    Full Text Available The aim of the present study was to examine the reliability of a novel multi-direction repeated sprint ability test (RSM; 10×(6×5-m compared with a repeated sprint ability test (RSA with one change of direction (10×(2×15-m, and the relationship of the RSM and RSA with Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1 and jump performances [squat jump (SJ and counter-movement-jump (CMJ]. Thirty-six (male, n=14, female n=22 young basketball players (age 16.0±0.9 yrs performed the RSM, RSA, Yo-Yo IR1, SJ and CMJ, and were re-tested only for RSM and RSA after one week. The absolute error of reliability (standard error of the measurement was lower than 0.212-s and 0.617-s for the time variables of the RSA and RSM test, respectively. Performance in the RSA and RSM test significantly correlated with CMJ and SJ. The best time, worst time and total time of the RSA and RSM test were negatively correlated with Yo-Yo IR1 distance. Based on these findings, consistent with previously published studies, it was concluded that the novel RSM test was valid and reliable.

  17. Aerobic and anaerobic determinants of repeated sprint ability in team sports athletes

    Directory of Open Access Journals (Sweden)

    Z Gharbi

    2015-09-01

    Full Text Available The aim of this study was to examine in team sports athletes the relationship between repeated sprint ability (RSA indices and both aerobic and anaerobic fitness components. Sixteen team-sport players were included (age, 23.4 ± 2.3 years; weight, 71.2 ± 8.3 kg; height, 178 ± 7 cm; body mass index, 22.4 ± 2 kg · m -2 ; estimated VO 2 max, 54.16 ± 3.5 mL · kg-1 · min-1. Subjects were licensed in various team sports: soccer (n = 8, basketball (n = 5, and handball (n = 3. They performed 4 tests: the 20 m multi-stage shuttle run test (MSRT, the 30-s Wingate test (WingT, the Maximal Anaerobic Shuttle Running Test (MASRT, and the RSA test (10 repetitions of 30 m shuttle sprints (15 + 15 m with 180° change of direction with 30 s passive recovery in between. Pearson’s product moment of correlation among the different physical tests was performed. No significant correlations were found between any RSA test indices and WingT. However, negative correlations were found between MASRT and RSA total sprint time (TT and fatigue index (FI (r = -0.53, p < 0.05 and r = -0.65, p < 0.01, respectively. No significant relationship between VO 2 max and RSA peak sprint time (PT and total sprint time (TT was found. Nevertheless, VO 2 max was significantly correlated with the RSA FI (r = -0.57, p < 0.05. In conclusion, aerobic fitness is an important factor influencing the ability to resist fatigue during RSA exercise. Our results highlighted the usefulness of MASRT, in contrast to WingT, as a specific anaerobic testing procedure to identify the anaerobic energy system contribution during RSA.

  18. Repeated sprint ability in soccer players: associations with physiological and neuromuscular factors.

    Science.gov (United States)

    Baldi, Marcelo; DA Silva, Juliano F; Buzzachera, Cosme F; Castagna, Carlo; Guglielmo, Luiz G

    2017-01-01

    The aim of this study was to examine the relationship between repeated sprint ability (RSA, 6×40 m [20+20 m] with 20-s recovery) and neuromuscular and aerobic fitness variables in male collegiate soccer players. Twenty-six players (age 22.5±3.6 years) were tested on separate days for countermovement jump (CMJ), squat jump (SJ), and standing long jump (LJ), and for maximal oxygen consumption (V̇O2max), velocity at onset of blood lactate accumulation (vOBLA), maximal aerobic speed (vV̇O2max), and peak blood lactate concentration (peak [La]). They were also tested for best and mean times on a repeated shuttle sprint ability test. RSA best time (r=-0.73 and r=-0.54) and RSA mean sprint time (r=-0.69 and r=-0.62) were significantly (Psprint time and sprint decrement with vOBLA (r=-0.44) and peak [La] (r=0.47), respectively. This study showed that RSA performance had a large to very large association with the individual level of jump performance and to a smaller extent to aerobic fitness variables in male collegiate soccer players. Given this finding, lower limbs' explosive-strength performance should be regarded as a relevant factor for male soccer.

  19. Aerobic and anaerobic determinants of repeated sprint ability in team sports athletes.

    Science.gov (United States)

    Gharbi, Z; Dardouri, W; Haj-Sassi, R; Chamari, K; Souissi, N

    2015-09-01

    The aim of this study was to examine in team sports athletes the relationship between repeated sprint ability (RSA) indices and both aerobic and anaerobic fitness components. Sixteen team-sport players were included (age, 23.4 ± 2.3 years; weight, 71.2 ± 8.3 kg; height, 178 ± 7 cm; body mass index, 22.4 ± 2 kg · m(-2); estimated VO2max, 54.16 ± 3.5 mL · kg(-1) · min(-1)). Subjects were licensed in various team sports: soccer (n = 8), basketball (n = 5), and handball (n = 3). They performed 4 tests: the 20 m multi-stage shuttle run test (MSRT), the 30-s Wingate test (WingT), the Maximal Anaerobic Shuttle Running Test (MASRT), and the RSA test (10 repetitions of 30 m shuttle sprints (15 + 15 m with 180° change of direction) with 30 s passive recovery in between). Pearson's product moment of correlation among the different physical tests was performed. No significant correlations were found between any RSA test indices and WingT. However, negative correlations were found between MASRT and RSA total sprint time (TT) and fatigue index (FI) (r = -0.53, p sprint time (PT) and total sprint time (TT) was found. Nevertheless, VO2max was significantly correlated with the RSA FI (r = -0.57, p ability to resist fatigue during RSA exercise. Our results highlighted the usefulness of MASRT, in contrast to WingT, as a specific anaerobic testing procedure to identify the anaerobic energy system contribution during RSA.

  20. Postactivation potentiation on repeated-sprint ability in elite handball players.

    Science.gov (United States)

    Okuno, Nilo M; Tricoli, Valmor; Silva, Salomão B C; Bertuzzi, Rômulo; Moreira, Alexandre; Kiss, Maria A P D M

    2013-03-01

    The aim of this study was to analyze the changes on repeated-sprint ability (RSA) performance after heavy load exercise in elite handball players. Twelve subjects were submitted to the following experimental sessions: (a) 1-repetition maximum (1RM) test on the half squat exercise, (b) RSA test (control condition), and (c) RSA with a conditioning activity on the same exercise as 1RM test (experimental condition). The conditioning activity comprised 1 set of 5 × 50% 1RM, 1 set of 3 × 70% 1RM, and 5 sets of 1 × 90% 1RM. A significant improvement in the best sprint time (RSAbest) and mean sprint time (RSAmean) was observed with the conditioning activity (RSAbest = 5.74 ± 0.16 seconds; RSAmean = 5.99 ± 0.19 seconds) when compared with the situation without the conditioning activity (RSAbest = 5.82 ± 0.15 seconds; RSAmean = 6.06 ± 0.18 seconds; p < 0.01) with a moderate (Cohen's d = -0.54) and small effect (Cohen's d = -0.41) to RSAbest and RSAmean, respectively. Therefore, the findings of this study demonstrated that prior heavy load exercise can be used to improve the RSA performance, however, with a small to moderate magnitude of change.

  1. Relationships between repeated sprint ability, mechanical parameters, and blood metabolites in professional soccer players.

    Science.gov (United States)

    Morcillo, Jose A; Jiménez-Reyes, Pedro; Cuadrado-Peñafiel, Victor; Lozano, Emilio; Ortega-Becerra, Manuel; Párraga, Juan

    2015-06-01

    This study analyzed the acute metabolic and mechanical responses to a specific repeated sprint ability (RSA) test. Eighteen male professional soccer players from a team of the First Division of Spanish National League participated. A 12 × 30-m RSA test with 30-second recovery together with countermovement jump test (CMJ) pre a post RSA test was performed. Mechanical responses (i.e., height performance in CMJ and speed loss) and metabolic responses (i.e., blood lactate and ammonia concentrations) were measured before and after exercise. A related sample t-test was used to analyze CMJ height pre-post changes as well as to compare pre- and post-exercise lactate and ammonia levels. Countermovement jump height loss pre-post session (8%) was significant, and fatigue, measured as CMJ height loss, was strongly correlated to lactate (r = 0.97; p < 0.001) and ammonia (r = 0.92; p < 0.001) for all players. The relationships between the variables studied were determined by calculating the Pearson correlation coefficients. The metabolic stress developed during the effort can be estimated by controlling CMJ because of the high correlation between CMJ and blood lactate and ammonia concentrations. The high correlations found between mechanical (speed and CMJ height losses) and metabolic (lactate and ammonia) measures of fatigue highlight the utility and validity of using CMJ to monitor training load and quantify objectively neuromuscular fatigue during RSA.

  2. Repeated sprint ability is not enhanced by caffeine, arginine, and branched-chain amino acids in moderately trained soccer players.

    Science.gov (United States)

    Ermolao, Andrea; Zanotto, Tobia; Carraro, Nicolò; Fornasier, Tommaso; Zaccaria, Marco; Neunhaeuserer, Daniel; Bergamin, Marco

    2017-02-01

    The aim was to investigate the effect of a dietary supplementation on the repeated sprint ability (RSA) performance in recreationally trained team sports athletes. Twelve young men underwent a RSA exercise protocol in five trials, in which participants ingested carbohydrates (CHO) plus caffeine (Caf), CHO plus arginine (Arg), CHO plus branched-chain amino acids (BCAA), CHO plus Caf, Arg, and BCAA (ALL), and CHO only. Heart rate, oxygen saturation, hematic lactate, ratings of perceived exertion, average sprint time, total time, best sprint time, peak power, and average power were taken. Data revealed no significant effects neither on physiological nor performance parameters with any of the supplements.

  3. Repeated sprint ability is not enhanced by caffeine, arginine, and branched-chain amino acids in moderately trained soccer players

    Science.gov (United States)

    Ermolao, Andrea; Zanotto, Tobia; Carraro, Nicolò; Fornasier, Tommaso; Zaccaria, Marco; Neunhaeuserer, Daniel; Bergamin, Marco

    2017-01-01

    The aim was to investigate the effect of a dietary supplementation on the repeated sprint ability (RSA) performance in recreationally trained team sports athletes. Twelve young men underwent a RSA exercise protocol in five trials, in which participants ingested carbohydrates (CHO) plus caffeine (Caf), CHO plus arginine (Arg), CHO plus branched-chain amino acids (BCAA), CHO plus Caf, Arg, and BCAA (ALL), and CHO only. Heart rate, oxygen saturation, hematic lactate, ratings of perceived exertion, average sprint time, total time, best sprint time, peak power, and average power were taken. Data revealed no significant effects neither on physiological nor performance parameters with any of the supplements. PMID:28349034

  4. Repeated sprint ability in elite water polo players and swimmers and its relationship to aerobic and anaerobic performance.

    Science.gov (United States)

    Meckel, Yoav; Bishop, David; Rabinovich, Moran; Kaufman, Leonid; Nemet, Dan; Eliakim, Alon

    2013-01-01

    The purpose of this study was to determine indices of swimming repeated sprint ability (RSA) in 19 elite water polo players compared to 16 elite swimmers during a repeated sprint swimming test (RST), and to examine the relationships between these indices and aerobic and anaerobic performance capabilities in both groups. Indices of RSA were determined by the ideal sprint time (IS), the total sprint time (TS), and the performance decrement (PD) recorded during an 8 x 15-m swimming RST. Single long - (800-m) and short-(25-m) distance swim tests were used to determined indices of aerobic and anaerobic swimming capabilities, respectively. The water polo players exhibited lower RSA swimming indices, as well as lower scores in the single short and long swim distances, compared to the swimmers. Significant relationships were found between the 25- m swim results and the IS and the TS, but not the PD of both the swimmers and the water polo players. No significant relationships were found between the 800-m swim results and any of the RSA indices in either the swimmers or the water polo players. No significant relationships were found between the 25-m and the 800-m swim results in either the swimmers or the water polo players. The results indicate that swimmers posses better RSA as well as higher anaerobic and aerobic capabilities, as reflected by the single short- and long-distance swim tests, compared to water polo players. The results also indicate that, as for running and cycling, repeated sprint swim performance is strongly related to single sprint performance. Key PointsElite water polo players demonstrated lower repeated sprint ability (RSA), aerobic and anaerobic capabilities compared to elite swimmers.A 25-m swim trial correlated significantly with ideal sprint time and total sprint time, emphasizing the important contribution of anaerobic metabolism for these exercise types in both water polo players and swimmers.800-m swim results did not correlate with RSA or 25-m

  5. Repeated sprint ability in young soccer players at different game stages.

    Science.gov (United States)

    Meckel, Yoav; Einy, Avner; Gottlieb, Roni; Eliakim, Alon

    2014-09-01

    The purpose of this study was to determine the repeated sprint ability (RSA) of young (16.9 ± 0.5 years) soccer players at different game stages. Players performed repeated sprint test (RST) (12 × 20 m) after warm-up before a game, at half-time, and after a full soccer game, each on a different day, in a random order. The ideal (fastest) sprint time (IS) and total (accumulative) sprint time (TS) were significantly slower at the end of the game compared with those after the warm-up before the game (p < 0.01 for each). Differences between IS and TS after the warm-up before the game and at half-time, and between half-time and end of the game, were not statistically significant. There was no significant difference in the performance decrement during the RST after warm-up before the game, at half-time, or the end of the game. Significant negative correlation was found between predicted V[Combining Dot Above]O2 and the difference between TS after the warm-up before the game and the end of the game (r = -0.52), but not between predicted V[Combining Dot Above]O2 and the difference in any of the RST performance indices between warm-up before the game and half-time, or between half-time and the end of the game. The findings indicate a significant RSA reduction only at the end but not at the half-time of a soccer game. The results also suggest that the contribution of the aerobic system to soccer intensity maintenance is crucial, mainly during the final stages of the game.

  6. Repeated Sprint Ability in Elite Water Polo Players and Swimmers and its Relationship to Aerobic and Anaerobic Performance

    Directory of Open Access Journals (Sweden)

    Yoav Meckel

    2013-12-01

    Full Text Available The purpose of this study was to determine indices of swimming repeated sprint ability (RSA in 19 elite water polo players compared to 16 elite swimmers during a repeated sprint swimming test (RST, and to examine the relationships between these indices and aerobic and anaerobic performance capabilities in both groups. Indices of RSA were determined by the ideal sprint time (IS, the total sprint time (TS, and the performance decrement (PD recorded during an 8 x 15-m swimming RST. Single long - (800-m and short-(25-m distance swim tests were used to determined indices of aerobic and anaerobic swimming capabilities, respectively. The water polo players exhibited lower RSA swimming indices, as well as lower scores in the single short and long swim distances, compared to the swimmers. Significant relationships were found between the 25- m swim results and the IS and the TS, but not the PD of both the swimmers and the water polo players. No significant relationships were found between the 800-m swim results and any of the RSA indices in either the swimmers or the water polo players. No significant relationships were found between the 25-m and the 800-m swim results in either the swimmers or the water polo players. The results indicate that swimmers posses better RSA as well as higher anaerobic and aerobic capabilities, as reflected by the single short- and long-distance swim tests, compared to water polo players. The results also indicate that, as for running and cycling, repeated sprint swim performance is strongly related to single sprint performance.

  7. The effect of slope on repeated sprint ability in young soccer players.

    Science.gov (United States)

    Padulo, J; Ardigò, L P; Attene, G; Cava, C; Wong, D P; Chamari, K; Migliaccio, G M

    2016-01-01

    This study aimed to describe a gradient repeated sprint ability (RSA) test in comparison with a standard level one by investigating performance, metabolic demand and muscular jumping performance as a proxy for running mechanics. Eighteen athletes performed two level RSA tests (40 m × 6) - for reliability evaluation - and one ±5% gradient RSA test, second leg downhill (RSAgrad). Rating of perceived exertion (RPE), blood lactate concentration (BLa) concentration, vertical jump heights were assessed as well. Level test measures resulted highly reliable (Intra-class correlation coefficient (ICC) ≥0.96). RSAgrad worsened only first sprints' performance (-2%) but not overall test performance (~45 s). RSAgrad resulted to be less deteriorating in terms of fatigue index (FI) (-36%), BLa (-23%), RPE (-11%), jumping performance (RSAgrad post-/pre-squat jump, countermovement jump heights (CMJh): -3%, -6%, respectively). RSAgrad could be used to diversify common training protocol without stressing excessively athletes' current metabolic-anaerobic capacity. Such physical conditioning procedures could improve acceleration/braking capability.

  8. Repeated-sprint ability and team selection in Australian football league players.

    Science.gov (United States)

    Le Rossignol, Peter; Gabbett, Tim J; Comerford, Dan; Stanton, Warren R

    2014-01-01

    To investigate the relationship between selected physical capacities and repeated-sprint performance of Australian Football League (AFL) players and to determine which physical capacities contributed to being selected for the first competition game. Sum of skinfolds, 40-m sprint (with 10-, 20-, 30-, and 40-m splits), repeated-sprint ability (6 × 30-m sprints), and 3-km-run time were measured during the preseason in 20 AFL players. The physical qualities of players selected to play the first match of the season and those not selected were compared. Pearson correlation coefficients were used to determine the relationship among variables, and a regression analysis identified variables significantly related to repeated-sprint performance. In the regression analysis, maximum velocity was the best predictor of repeated-sprint time, with 3-km-run time also contributing significantly to the predictive model. Sum of skinfolds was significantly correlated with 10-m (r = .61, P sprint times. A 2.6% ± 2.1% difference in repeated-sprint time (P repeated-sprint performance in AFL players than short 10- to 20-m intervals from standing starts. Further research is warranted to establish the relative importance of endurance training for improving repeated-sprint performance in AFL football.

  9. Altering Work to Rest Ratios Differentially Influences Fatigue Indices During Repeated Sprint Ability Testing.

    Science.gov (United States)

    La Monica, Michael B; Fukuda, David H; Beyer, Kyle S; Hoffman, Mattan W; Miramonti, Amelia A; Riffe, Josh J; Baker, Kayla M; Fragala, Maren S; Hoffman, Jay R; Stout, Jeffrey R

    2016-02-01

    This study examined the influence of recovery time on fatigue indices, performance (total work [TW], peak power [PP], and mean power [MP]), and oxygen consumption during repeated sprint ability (RSA) on a cycle ergometer. Eight recreationally-trained men performed 3 RSA protocols consisting of 10 × 6 s sprints with 12 s, 18 s, and 24 s rest intervals between each sprint. Fatigue indices were determined as percent decrement (%Dec) and rate of decline using either a log transform method or standard slope approach for TW, PP, and MP during respective RSA protocols. The maximal VO2 value in response to given sprint intervals and the minimal VO2 value in response to given rest periods (VO2 work and VO2 rest, respectively) were recorded. A repeated measures analysis of variance was used to analyze all variables. Average VO2 work was not different among rest interval trials. Average VO2 rest with 12 s rest was greater than 18 s and 24 s (2.16 ± 0.17 L · min(-1), 1.91 ± 0.18 L · min(-1), 1.72 ± 0.15 L · min(-1), respectively), while 18 s was greater than 24 s. Average TW and MP were greater with 24 s rest than 12 s (4,604.44 ± 915.98 J vs. 4,305.46 ± 727.17 J, respectively), with no differences between RSA protocols for PP. No differences in %Dec were observed. Both methods of calculating rates of decline per sprint for PP and TW were greater during 12 s than 18 s or 24 s. Since changes were only noted between the 12 s and 24 s protocols, a 6 s differential in rest intervals may not be enough to elicit alterations in TW, PP, MP, or %Dec in RSA performance. Rate of decline may be a more sensitive measure of fatigue than %Dec.

  10. Improving repeated sprint ability in young elite soccer players: repeated shuttle sprints vs. explosive strength training.

    Science.gov (United States)

    Buchheit, Martin; Mendez-Villanueva, Alberto; Delhomel, Gregory; Brughelli, Matt; Ahmaidi, Said

    2010-10-01

    To compare the effects of explosive strength (ExpS) vs. repeated shuttle sprint (RS) training on repeated sprint ability (RSA) in young elite soccer players, 15 elite male adolescents (14.5 ± 0.5 years) performed, in addition to their soccer training program, RS (n = 7) or ExpS (n = 8) training once a week for a total of 10 weeks. RS training consisted of 2-3 sets of 5-6 × 15- to 20-m repeated shuttle sprints interspersed with 14 seconds of passive or 23 seconds of active recovery (≈2 m·s⁻¹); ExpS training consisted of 4-6 series of 4-6 exercises (e.g., maximal unilateral countermovement jumps (CMJs), calf and squat plyometric jumps, and short sprints). Before and after training, performance was assessed by 10 and 30 m (10 and 30 m) sprint times, best (RSAbest) and mean (RSAmean) times on a repeated shuttle sprint ability test, a CMJ, and a hopping (Hop) test. After training, except for 10 m (p = 0.22), all performances were significantly improved in both groups (all p's repeated shuttle sprint test were only observed after RS training, whereas CMJ height was only increased after ExpS. Because RS and ExpS were equally efficient at enhancing maximal sprinting speed, RS training-induced improvements in RSA were likely more related to progresses in the ability to change direction.

  11. Repeated Sprint Ability in Young Basketball Players: Multi-direction vs. One-Change of Direction (Part 1).

    Science.gov (United States)

    Padulo, Johnny; Bragazzi, Nicola L; Nikolaidis, Pantelis T; Dello Iacono, Antonio; Attene, Giuseppe; Pizzolato, Fabio; Dal Pupo, Juliano; Zagatto, Alessandro M; Oggianu, Marcello; Migliaccio, Gian M

    2016-01-01

    The aim of the present study was to examine the reliability of a novel multi-direction repeated sprint ability (RSA) test [RSM; 10 × (6 × 5-m)] compared with a RSA with one change of direction [10 × (2 × 15-m)], and the relationship of the RSM and RSA with Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1) and jump performances [squat jump (SJ) and counter-movement-jump (CMJ)]. Thirty-six (male, n = 14, female n = 22) young basketball players (age 16.0 ± 0.9 yrs) performed the RSM, RSA, Yo-Yo IR1, SJ, and CMJ, and were re-tested only for RSM and RSA after 1 week. The absolute error of reliability (standard error of the measurement) was lower than 0.212 and 0.617-s for the time variables of the RSA and RSM test, respectively. Performance in the RSA and RSM test significantly correlated with CMJ and SJ. The best time, worst time, and total time of the RSA and RSM test were negatively correlated with Yo-Yo IR1 distance. Based on these findings, consistent with previously published studies, it was concluded that the novel RSM test was valid and reliable.

  12. Evaluation of critical rest interval determined from repeated sprint ability testing.

    Science.gov (United States)

    LA Monica, Michael B; Fukuda, David H; Beyer, Kyle S; Hoffman, Mattan W; Miramonti, Amelia A; Fragala, Maren S; Stout, Jeffrey R; Hoffman, Jay R

    2016-10-01

    To test if the critical power (CP) concept can be utilized to determine the critical rest interval (CRI) using repeated sprint ability (RSA) testing with varying work-to-rest ratios. Twelve recreationally trained men (mean±SD; age 24.1±3.6 years) completed a graded exercise test and three RSA protocols with 6-second maximal sprints and varying rest intervals (12-36 s) on a cycle ergometer to determine CRI. Intermittent critical power (ICP) was calculated through the linear total work (TW) and time-to-exhaustion (TTE) relationship, whereas CRI was estimated using average work per sprint and ICP. Validation trials above and below CRI were conducted to evaluate physiological response. Repeated measures analysis of variance were used to analyze variables from RSA trials and changes in blood lactate, oxygen uptake (V̇O2), heart rate (HR), peak power, and TW throughout the validation trials. Blood lactate, average V̇O2, V̇O2peak, and heart rate were significantly greater below CRI (8.94±4.89 mmol/L, 2.05±0.36 L/min, 2.84±0.48 L/min, and 151.14±18.46 bpm, respectively) when compared to above CRI (6.56±3.45 mmol/L, 1.78±0.26 L/min, 2.61±0.43 L/min, and 138.14±17.51 bpm). Significant interactions were found between above and below CRI for minimal V̇O2 response and maximal HR response, which were consistent with the heavy and severe exercise intensity domains. The use of the work-time relationship determined from RSA testing with varying rest intervals can be used to determine CRI and may distinguish between physiological responses related to exercise intensity domains.

  13. Sympathetic enhancement in futsal players but not in football players after repeated sprint ability test.

    Science.gov (United States)

    Chen, Yung-Sheng; Liao, Chih-Jung; Lu, Wan-An; Kuo, Cheng-Deng

    2015-01-01

    Heart rate variability (HRV) can disclose the specific adaptation of sympathovagal modulation to exercise. This study investigated the change in HRV measures after anaerobic and aerobic intermittent exercises in university football and futsal players. 36 male university students with physically active lifestyle (n=14), football (n=12), and futsal (n=10) participated in this study. The participants completed the repeated sprint ability (RSA) test and Yo-Yo (YY) intermittent recovery test level 1 in randomised order. ECG signals of the participants were recorded in supine position 15 min before and 30 min after exercises. Before exercise, and 5 and 30 min after exercise, the blood pressures were also taken. In the RSA protocol, the percentage changes in normalised high-frequency power (nHFP) were significantly decreased, while the percentage changes in the very low/high frequency power ratio (VLHR) and low/high frequency power ratio (LHR) were significantly increased in futsal players after exercise, as compared with the controls. No significant changes in all HRV indices were found in the YY protocol, except the respiratory frequency. After exercise, the percent decrease in vagal modulation in futsal players was significantly reduced, while the percentage increase in sympathetic modulation in futsal players was significantly enhanced in the RSA test, but not in the YY test, as compared with the control group. The increase in sympathetic activity and the decrease in vagal activity in the futsal players were greater than the corresponding increase and decrease in the football players in the RSA test.

  14. The Effects of Novel Ingestion of Sodium Bicarbonate on Repeated Sprint Ability.

    Science.gov (United States)

    Miller, Peter; Robinson, Amy L; Sparks, S Andy; Bridge, Craig A; Bentley, David J; McNaughton, Lars R

    2016-02-01

    This work examined the influence of an acute dose of sodium bicarbonate (NaHCO3) on buffering capacity and performance during a repeated sprint ability (RSA) protocol. Eleven (mean ± SD: age 24.6 ± 6.1 years; mass 74.9 ± 5.7 kg; height 177.2 ± 6.7 cm) participated in the study, undertaking 4 test sessions. On the first visit to the laboratory, each participant ingested 300 mg · kg(-1) of NaHCO3 (in 450 ml of flavored water) and blood samples were obtained at regular intervals to determine the individual times peak pH and HCO3. In subsequent visits, participants ingested 300 mg · kg(-1) of NaHCO3, 270 mg · kg(-1) body mass (BM) of NaCI, or no drink followed by a RSA cycling protocol (10 × 6 seconds sprints with 60 seconds recovery), which commenced at each individuals predetermined ingestion peak pH response time. Blood samples were obtained before exercise and after the first, fifth, and 10th sprint to determine the blood pH, HCO3, and lactate (La) responses. Total work completed during the repeated sprint protocol was higher (p ≤ 0.05) in the NaHCO3 condition (69.8 ± 11.7 kJ) compared with both the control (59.6 ± 12.2 kJ) and placebo (63.0 ± 8.3 kJ) conditions. Peak power output was similar (p > 0.05) between the 3 conditions. Relative to the control and placebo conditions, NaHCO3 ingestion induced higher (p ≤ 0.05) blood pH and HCO3 concentrations before exercise and during the bouts, and higher lactate concentrations (p ≤ 0.05) after the final sprint. Results suggest that NaHCO3 improves the total amount of work completed during RSA through enhanced buffering capacity.

  15. Are "classical" tests of repeated-sprint ability in football externally valid? A new approach to determine in-game sprinting behaviour in elite football players.

    Science.gov (United States)

    Schimpchen, Jan; Skorski, Sabrina; Nopp, Stephan; Meyer, Tim

    2016-01-01

    The aim of this study was to investigate the occurrence of repeated sprinting bouts in elite football. Furthermore, the construct validity of current tests assessing repeated-sprint ability (RSA) was analysed using information of sprinting sequences as they actually occurred during match-play. Sprinting behaviour in official competition was analysed for 19 games of the German national team between August 2012 and June 2014. A sprinting threshold was individually calculated based on the peak velocity reached during in-game sprinting. Players performed 17.2 ± 3.9 sprints per game and during the entire 19 games a total of 35 bouts of repeated sprinting (a minimum of three consecutive sprints with a recovery duration repeated sprinting per player every 463 min. No general decrement in maximal sprinting speed was observed during bouts with up to five consecutive sprints. Results of the present study question the importance of RSA as it is classically defined. They indicate that shorter accelerations are more important in game-specific situations which do not reach speeds necessary to qualify them as sprints. The construct validity of classic tests of RSA in football is not supported by these observations.

  16. Relationship between measures of aerobic fitness, speed and repeated sprint ability in full and part time youth soccer players.

    Science.gov (United States)

    Gibson, N; Currie, J; Johnston, R; Hill, J

    2013-02-01

    The aim of the study was to investigate the relationship between repeated sprint ability (RSA) involving changes in direction, short linear sprinting and aerobic capacity in young elite soccer players. A secondary aim was to assess any differences in performance of these assessments between players of different age groups. Thirty-two male adolescent soccer players belonging to the same elite club academy were assessed for RSA comprising 6 x 40m efforts interspersed by 25s recovery, linear sprinting speed over 15m, and aerobic capacity via the YYIE2 assessment. There was a significant correlation between performance in the YYIE2 and RSA total time, RSA fastest sprint and RSA percentage decrement (r = -0.71, -0.53, and -0.52 respectively. Psprint (Psprinting. Assessments of RSA over 40m and incorporating changes of direction appear to be significantly correlated with YYIE2 performance in young elite level soccer players. In addition older players performed significantly better in the YYIE2 assessment and RSA protocol but not in short linear sprinting. These results have implications for the design of assessment protocols for young elite soccer players of different ages.

  17. The development of a test of repeated-sprint ability for elite women's soccer players.

    Science.gov (United States)

    Gabbett, Tim J

    2010-05-01

    The purpose of this study was to develop a game-specific test of repeated-sprint ability for elite women's soccer players. Nineteen elite women's soccer players (mean +/- SD; age, 18.1 +/- 2.9 y) participated in this study. After familiarization, players completed a repeated-sprint test consisting of 6 x 20-m maximal effort sprints, on a 15-second cycle. At the completion of each sprint, players performed a 10-m deceleration and a 10-m active jog recovery. Ten elite female soccer players performed the test on 2 occasions, 1 week apart, to determine the reliability of the test. In addition, the validity of the repeated-sprint test to discriminate among players of different playing ability was evaluated by testing national (n = 11) and state (n = 8) women's soccer players. Heart rate and blood lactate concentration were recorded to determine the physiological responses to the test. The total sprint time proved to be highly reproducible (intraclass correlation coefficient = 0.91; typical error of measurement = 1.5%). However, the percentage decrement was less reliable (intraclass correlation coefficient = 0.14, typical error of measurement = 19.5%). The repeated-sprint test was valid in discriminating between national- and state-level players, with national players having significantly lower (p repeated-sprint times than state players (20.9 +/- 0.5 s vs. 23.3 +/- 0.4 s). The mean (+/-SD) heart rate and blood lactate concentration were 182 +/- 6 beats/min and 9.3 +/- 2.0 mmol/L, respectively. The results of this study demonstrate that the developed repeated-sprint test discriminates players of higher and lesser skill levels and offers a reliable method of assessing repeated-sprint ability in elite women's soccer players when results are expressed as the total sprint time.

  18. Avaliação da capacidade de realizar sprints repetidos no futebol Repeated sprint ability evaluation in soccer

    Directory of Open Access Journals (Sweden)

    Henrique Bortolotti

    2010-12-01

    Full Text Available A maioria dos esportes coletivos (ex.: futebol, basquete, handebol tem como característica a intermitência, flutuando entre breves períodos de esforços máximos ou próximos ao máximo seguidos de períodos e formas de recuperação. Alguns autores têm proposto diversos testes que tem por finalidade mensurar a capacidade desses atletas em realizar esforços repetidos máximos (RSA, a qual estaria diretamente relacionada aos momentos decisivos durante partida. Dessa forma, o presente estudo teve como objetivo descrever os diferentes protocolos de testes para avaliar a RSA em jogadores de futebol, com base em artigos originais e algumas revisões levantadas na base de dados Medline. Diante dos achados, sugerimos a utilização de quatro protocolos, dois envolvendo sprints lineares (AZIZ et al., 2008; REILLY, 2001 e dois utilizando sprints com mudanças de direção (BANGSBO, 2008; IMPELLIZZERI et al., 2008 para avaliação da RSA em jogadores de futebol, gerando importantes parâmetros de desempenho, que permitem ainda a elaboração de programas de treinamento para a melhora dessa capacidade. Recomendamos ainda, a utilização do tempo médio e/ou total como uma medida geral da capacidade de realizar sprints repetidos e as parciais de tempo de cada sprint para identificar possíveis pontos fortes e fraco de cada atleta.The most of team sports (soccer, basketball, handball is characterized by intermittency, fluctuating between brief periods of maximum effort or near the maximum followed by periods and forms of recovery. Some authors have proposed several tests to measure the ability of these athletes to perform repeated sprints (repeated sprint ability - RSA, which would be directly related to the decisive moments during match. Then, this study aimed to describe the different test protocols to assess RSA in soccer players, based on original articles and reviews selected in some databases (Medline. Therefore, we suggest four protocols, two

  19. Is there a diurnal variation in repeated sprint ability on a non-motorised treadmill?

    Science.gov (United States)

    Pullinger, Samuel A; Brocklehurst, Emma L; Iveson, Reece P; Burniston, Jatin G; Doran, Dominic A; Waterhouse, James M; Edwards, Ben J

    2014-04-01

    In active males, muscle force production and short-term (variation is attributed to motivational, peripheral and central factors, and possibly the higher core and muscle temperatures observed in the evening. However, little is known regarding whether diurnal variation on a treadmill also exists in team-sport specific tests of repeated sprint ability (RSA), as would be relevant to football, for example. A controlled laboratory protocol using a non-motorised treadmill has been used to investigate whether daily variation in RSA is present in highly motivated athletes. Twenty active males (mean ± SD: age, 21.0 ± 2.2 yrs; maximal oxygen uptake ([Formula: see text] max), 60.8 ± 4.8 ml kg min(-1); body mass, 77.02 ± 10.5 kg and height, 1.79 ± 0.07 m) volunteered and completed two sessions counterbalanced in order of administration (separated by >48 h): a morning (M, 07:30 h) and evening (E, 17:30 h) session. Both sessions included a 5-min active warm-up on a motorised treadmill at 10 km h(-1) followed by three task-specific warm-up sprints at 50%, 70% and 80%, respectively, on a non-motorised treadmill. During each trial, 10 × 3 s repeated sprints with 30 s recoveries were performed on the non-motorised treadmill. Rectal (Trec) and muscle temperature measurements (Tm) were taken after subjects had reclined for 30 min at the start of the protocol, and again after the active warm-up. Values of heart rate, thermal comfort (TC), rating of perceived exertion (RPE) and effort were measured throughout. Blood samples were taken at rest, after the sprints and 5-min post sprints. Data were analysed using a GLM with repeated measures. Trec and Tm values were higher at rest in the evening than the morning (0.46 °C and 0.57 °C, respectively, p p > 0.05). All subjects reported maximal values for "effort" for each sprint. There were significant positive correlations between Trec and Tm, Trec and RPE, TC and all measures of RSA performance. However, there was no correlation

  20. Performance and Metabolic Demand of a New Repeated-Sprint Ability Test in Basketball Players: Does the Number of Changes of Direction Matter?

    Science.gov (United States)

    Zagatto, Alessandro M; Ardigò, Luca P; Barbieri, Fabio A; Milioni, Fabio; Dello Iacono, Antonio; Camargo, Bruno H F; Padulo, Johnny

    2017-09-01

    Zagatto, AM, Ardigò, LP, Barbieri, FA, Milioni, F, Dello Iacono, A, Camargo, BHF, and Padulo, J. Performance and metabolic demand of a new repeated-sprint ability test in basketball players: does the number of changes of direction matter? J Strength Cond Res 31(9): 2438-2446, 2017-This study compared 2 repeated-sprint ability (RSA) tests in basketball players. Both tests included 10 × 30-m sprints, with the difference that the previously validated test (RSA2COD) featured 2 changes of direction (COD) per sprint, whereas the experimental test (RSA5COD) featured 5 CODs per sprint. Test performances and metabolic demands were specifically assessed in 20 basketball players. First, RSA5COD test-retest reliability was investigated. Then, RSA2COD, RSA5COD sprint times, peak speeds, oxygen uptake (V[Combining Dot Above]O2) and posttest blood lactate concentration [La] were measured. The RSA5COD results showed to be reliable. RSA2COD performance resulted better than the RSA5COD version (p sprint times and higher peak speeds. Over sprints, the tests did not differ from each other in terms of V[Combining Dot Above]O2 (p > 0.05). Over whole bout, the RSA2COD was more demanding than the RSA5COD, considering overall metabolic power requirement (i.e., VO2-driven + [La]-driven components). Given that RSA5COD (a) mimics real game-play as sprint distance and action change frequency/direction and (b) has the same metabolic expenditure per task completion as metabolic cost, RSA5COD is a valuable option for players and coaches for training basketball-specific agility and assessing bioenergetic demands.

  1. Effetti dell'allenamento intermittente breve ad alta intensità e delle ripetute aerobiche sul Test Repeated Sprint Ability in giovani calciatori d'elite

    OpenAIRE

    Ibba, Gianfranco

    2016-01-01

    The purpose of this study is to evaluate the effects of two different training methods: the repeated aerobic bouts and the short intermittent high intensity workout on the ability to carry out repeated sprint bouts RSA in a group of young soccer players and also to determine the impact of training on aerobic and neuromuscular performances. Twenty-Four (24) male soccer players have been assessed and trained, all of them partecipating regularly in the 2013-2014 season at the Nati...

  2. Reliability of specific on-ice repeated-sprint ability test for ice-hockey players

    Directory of Open Access Journals (Sweden)

    Karel Hůlka

    2014-06-01

    Full Text Available Background: Repeated sprint ability tests are today widely used to evaluate the performance capability in team sports. Objective: The aim of this study was to determine the reliability of a specific ice hockey test, which indicates the agility and repeated-sprint ability of the players. Methods: Twenty four highly trained junior ice hockey players (age = 17.68 ± 1.52 years; BMI = 23.8 ± 1.92 kg . m-2 participated in the study. Each participant was assessed for specific on-ice repeated-sprint ability test 12 × 54 m with 30 s rest. Intraclass correlation coefficient (association between two repeated measurements and coefficient of variation were calculated to assess the reliability of the test. Results: All intraclass correlation coefficients were .78 for sprint decrement and .98 for total time and the best time, the coefficient of variation was 1.52% for best sprint time, 1.31% for total time and 19.3% for sprint decrement variable. Conclusions: The results suggest the high reliability of the ice hockey agility test expressed by the best sprint time and repeated-sprint ability by the total time and less reliability of sprint decrement.

  3. The effect of an official match on repeated sprint ability in junior basketball players.

    Science.gov (United States)

    Caprino, Davide; Clarke, Neil David; Delextrat, Anne

    2012-01-01

    The aim of this study was to investigate the effect of an official basketball match on repeated sprint ability indices in male junior players. Ten (16 ± 1 years old; 183.6 ± 7.0 cm; 76.6 ± 8.0 kg) starting players for their teams performed three repeated sprint ability tests, before, at half-time and immediately after an official match. Each repeated sprint ability test consisted of 10 shuttle-run sprints of 30 m (15 + 15 m) separated by 30 seconds of passive recovery. The matches were video-taped to determine the frequency of eight types of movement patterns, and blood lactate concentration was measured before and immediately after each repeated sprint ability test. Differences in total time, ideal time and percentage decrement between tests was assessed by a one-way analysis of variance (ANOVA) with repeated measures, while a two-way ANOVA with repeated measures was used to identify differences in blood lactate concentration. The main results indicated a significant decrease in total movement frequency (-9.9%), high-intensity activity frequency (-13.3%), run frequency (-13.0%) and sprint frequency (-23.3%) in the second compared to the first half, and significantly worse total time and ideal time at the end of the match, compared to the start and half-time (differences ranging from -2.1% to -2.9%, P < 0.05). The practical implications of these findings suggest that regional basketball players should participate in conditioning sessions that focus on the improvement of repeated sprint ability.

  4. Fitness determinants of repeated-sprint ability in highly trained youth football players.

    Science.gov (United States)

    Spencer, Matt; Pyne, David; Santisteban, Juanma; Mujika, Iñigo

    2011-12-01

    Variations in rates of growth and development in young football players can influence relationships among various fitness qualities. To investigate the relationships between repeated-sprint ability and other fundamental fitness qualities of acceleration, agility, explosive leg power, and aerobic conditioning through the age groups of U11 to U18 in highly trained junior football players. Male players (n = 119) across the age groups completed a fitness assessment battery over two testing sessions. The first session consisted of countermovement jumps without and with arm swing, 15-m sprint run, 15-m agility run, and the 20-m Shuttle Run (U11 to U15) or the Yo-Yo Intermittent Recovery Test, Level 1 (U16 to U18). The players were tested for repeated-sprint ability in the second testing session using a protocol of 6 × 30-m sprints on 30 s with an active recovery. The correlations of repeated-sprint ability with the assorted fitness tests varied considerably between the age groups, especially for agility (r = .02 to .92) and explosive leg power (r = .04 to .84). Correlations of repeated sprint ability with acceleration (r = .48 to .93) and aerobic conditioning (r = .28 to .68) were less variable with age. Repeated-sprint ability associates differently with other fundamental fitness tests throughout the teenage years in highly trained football players, although stabilization of these relationships occurs by the age of 18 y. Coaches in junior football should prescribe physical training accounting for variations in short-term disruptions or impairment of physical performance during this developmental period.

  5. Is repeated-sprint ability of soccer players predictable from field-based or laboratory physiological tests?

    Science.gov (United States)

    Psotta, R; Bunc, V; Hendl, J; Tenney, D; Heller, J

    2011-03-01

    The aim of this study was to investigate multiple regression models with prediction equations that would enable a valid estimate of running repeated-sprint ability (RSA) in soccer players from the variables measured in field and laboratory physiological tests. Adolescent soccer players (N=33) performed five field performance tests and two laboratory tests for assessment of muscle strength of legs, sprint ability, anaerobic power and capacity, aerobic power and capacity, and running economy. These tests served as potential predictors of RSA. RSA was assessed by a intermittent anaerobic running test (IAnRT) consisted of ten 20 m sprints. Multiple regression analysis revealed that the mean speed in the 20 m sprint test and the 2 km endurance running test accounted for 89% of total variation in the mean running speed in the IAnRT (VIAnRT) as the indicator of capacity for multiple sprint work (R2=0.89, SEM=0.09 m.s-1). Using the variables from the laboratory tests, the best prediction of the VIAnRT was obtained from the running speed at the ventilatory threshold level (VVT) and anaerobic power (Pmax.kg-1) (R2=0.49, SEM=0.21 m.s-1). Performance in the multiple-sprint exercise as an indicator of RSA can be estimated by the regression equation with two predictors - mean speed in the 20 m sprint and 2 km running test with an error of 4%.

  6. Improving acceleration and repeated sprint ability in well-trained adolescent handball players: speed versus sprint interval training.

    Science.gov (United States)

    Buchheit, Martin; Mendez-Villanueva, Alberto; Quod, Marc; Quesnel, Thomas; Ahmaidi, Said

    2010-06-01

    The aim of the current study was to compare the effects of speed/agility (S/A) training with sprint interval training (SIT) on acceleration and repeated sprint ability (RSA) in well-trained male handball players. In addition to their normal training program, players performed either S/A (n = 7) or SIT (n = 7) training for 4 wk. Speed/agility sessions consisted of 3 to 4 series of 4 to 6 exercises (eg, agility drills, standing start and very short sprints, all of Sprint interval training consisted of 3 to 5 repetitions of 30-s all-out shuttle sprints over 40 m, interspersed with 2 min of passive recovery. Pre- and posttests included a countermovement jump (CMJ), 10-m sprint (10m), RSA test and a graded intermittent aerobic test (30-15 Intermittent Fitness Test, V(IFT)). S/A training produced a very likely greater improvement in 10-m sprint (+4.6%, 90% CL 1.2 to 7.8), best (+2.7%, 90% CL 0.1 to 5.2) and mean (+2.2%, 90% CL -0.2 to 4.5) RSA times than SIT (all effect sizes [ES] greater than 0.79). In contrast, SIT resulted in an almost certain greater improvement in V(IFT) compared with S/A (+5.2%, 90% CL 3.5 to 6.9, with ES = -0.83). In well-trained handball players, 4 wk of SIT is likely to have a moderate impact on intermittent endurance capacity only, whereas S/A training is likely to improve acceleration and repeated sprint performance.

  7. Can a Repeated Sprint Ability Test Help Clear a Previously Injured Soccer Player for Fully Functional Return to Activity? A Pilot Study.

    Science.gov (United States)

    Padulo, Johnny; Attene, Giuseppe; Ardigò, Luca P; Bragazzi, Nicola L; Maffulli, Nicola; Zagatto, Alessandro M; Dello Iacono, Antonio

    2017-07-01

    To investigate the effects of fatigue induced by a repeated sprint ability (RSA) test on the neuromuscular responses of soccer players with a recent history of lower limb injuries (CH) and a matched control group in good fitness condition (GH). This was a case-control study. Nine CH and 9 GH. Allocation to CH or GH. Each player was assessed for blood lactate concentration and jumping performance [squat jump (SJ) and countermovement jump (CMJ)] before/after RSA. Post-RSA rate of perceived exertion (RPE) was obtained. Receiver operating characteristic analysis was performed to calculate RSA sensitivity and specificity in distinguishing between CH and GH. Intraclass correlation coefficient was used to assess reliability. No baseline differences were found for any variable. ΔSJ before/after RSA was -14 ± 2% and -5 ± 2% in CH and GH, respectively (P Repeated sprint ability is a simple, low-cost field test potentially able to assist in clinical decision making for return to sport.

  8. Age-related differences in repeated-sprint ability in highly trained youth football players.

    Science.gov (United States)

    Mujika, Inigo; Spencer, Matt; Santisteban, Juanma; Goiriena, Juan Jose; Bishop, David

    2009-12-01

    In this study, we investigated the age-related differences in repeated-sprint ability and blood lactate responses in 134 youth football players. Players from the development programme of a professional club were grouped according to their respective under-age team (U-11 to U-18). Following familiarization, the participants performed a repeated-sprint ability test [6 x 30-m sprints 30 s apart, with active recovery (2.0-2.2 m . s(-1)) between sprints]. The test variables were total time, percent sprint decrement, and post-test peak lactate concentration. Total time improved from the U-11 to U-15 age groups (range 33.15 +/- 1.84 vs. 27.25 +/- 0.82 s), whereas no further significant improvements were evident from U-15 to U-18. No significant differences in percent sprint decrement were reported among groups (range 4.0 +/- 1.0% to 5.5 +/- 2.1%). Post-test peak lactate increased from one age group to the next (range 7.3 +/- 1.8 to 12.6 +/- 1.6 mmol . l(-1)), but remained constant when adjusted for age-related difference in body mass. Peak lactate concentration was moderately correlated with sprint time (r = 0.70, P > 0.001). Our results suggest that performance in repeated-sprint ability improves during maturation of highly trained youth football players, although a plateau occurs from 15 years of age. In contrast to expectations based on previous suggestions, percent sprint decrement during repeated sprints did not deteriorate with age.

  9. Acute effects of two different initial heart rates on testing the Repeated Sprint Ability in young soccer players.

    Science.gov (United States)

    Ruscello, B; Briotti, G; Tozzo, N; Partipilo, F; Taraborelli, M; Zeppetella, A; Padulo, J; D'Ottavio, S

    2015-10-01

    The aim of this paper was to investigate the acute effects of two different initial heart rates intensities when testing the repeated sprint ability (RSA) performances in young soccer players. Since there are many kinds of pre-match warm-ups, we chose to take as an absolute indicator of internal load the heart rate reached at the end of two different warm-up protocols (60 vs. 90% HRmax) and to compare the respective RSA performances. The RSA tests were performed on fifteen male soccer players (age: 17.9±1.5 years) with two sets of ten shuttle-sprints (15+15 m) with a 1:3 exercise to rest ratio, in different days (randomized order) with different HR% (60 & 90% HRmax). In order to compare the different sprint performances a Fatigue Index (FI%) was computed, while the blood lactate concentrations (BLa-) were measured before and after testing, to compare metabolic demand. Significant differences among trials within each sets (P4 mmol/L(-1)).

  10. Muscle power and repeated sprint ability in soccer players

    Directory of Open Access Journals (Sweden)

    Saray Giovana dos Santos

    2010-06-01

    Full Text Available Muscle power is one of the most important physical qualities of soccer playerperformance and needs to be maintained during a match. Thus, the aim of this study was toinvestigate the levels of muscle power in soccer players before and after performing repeatedsprints (RS, and the association between power and RS performance. Twenty soccer playersfrom the under-20 category aged 18-20 years participated in this study. The study consisted ofthe execution of vertical jumps, execution of RS, new execution of vertical jumps, and collectionof blood samples. The continuous jump (CJ test was performed on a piezoelectric force platformfor the measurement of muscle power and the RAST test was used to evaluate RS ability. Nosignificant difference in the levels of muscle power was observed after RS (p=0.57. Significantdifferences were observed in the first to fifth sprint times (p<0.01, but not between the fifth andsixth sprint (p=0.06. CJ height before RS was correlated with first sprint time (r=-0.62, p<0.01,best sprint time (r=-0.60, p<0.01, and average sprint time (r= -0.54, p<0.01. In conclusion,the soccer players studied showed no significant reduction in muscle power after RS. A decreasein performance was observed from the first to the fifth sprint, but not between the fifth and sixthsprint. The muscle power of soccer players was a determinant factor to perform one maximumsprint, as well as successive sprints.

  11. Comparison of shuttle and straight repeated-sprint ability tests and their relationship to anthropometrics and explosive muscular performance of lower limb in elite handball players.

    Science.gov (United States)

    Hermassi, Souhail; Schwesig, René; Wollny, Rainer; Fieseler, Georg; van den Tillaar, Roland; Fernandez-Fernandez, Jaime; Shephard, Roy J; Chelly, Mohamed S

    2017-06-21

    This study assessed inter-relationships between shuttle and straight repeated-sprint ability tests and the relationship of each measure to anthropometric and explosive lower limb performance data in elite handball players. Twenty-two elite male handball players (18.9 ± 0.2 years; body mass: 83.3 ± 1.1 kg, height: 1.79 ± 2.30 m, body fat: 12.8 ± 0.2%) completed tests that included a lower limb force-velocity test of peak power (Wpeak), jumping ability (squat and counter-movement jumps; SJ, CMJ), 1 repetition maximum (1-RM) half back squat, average sprint velocity over 5 m (V-5 m), peak velocity between 25-30 m (Vmax), and Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IR1), and anthropometric determinations of cross-sectional areas and muscle volumes for leg and thigh muscles. Data were compared with performance on 2 repeated sprint tests; the straight test [6 × 30 m (RSA30)] and the intermittent test [6 x (2 x 15 m) shuttle sprints (RSA15)]. V-5 m; 1-RM; and thigh and leg muscle cross-sectional areas and volumes showed relevant relationships to the shuttle RSA test (r2≥0.5). The Yo-Yo IR1 explained the largest percentage of variance in RSA15 total time (60%), and V-5 m also explained 56% of the variance in RSA15 total time. RSA15% fatigue was only related to 1-RM (explained variance: 58%), and the RSA30 test showed no useful correlations with any of the investigated predictors. Multiple-regression analyses using all physical tests explained 91% of the variance in RSA15 total time (prepeated sprints over distances of 15 m or less. RSA15 is related to muscular power, maximal strength, speed and endurance performance; however, the straight repeated sprint ability test is not, and thus does not seem relevant for the testing of handball players.

  12. Repeated sprint training in normobaric hypoxia.

    Science.gov (United States)

    Galvin, Harvey M; Cooke, Karl; Sumners, David P; Mileva, Katya N; Bowtell, Joanna L

    2013-12-01

    Repeated sprint ability (RSA) is a critical success factor for intermittent sport performance. Repeated sprint training has been shown to improve RSA, we hypothesised that hypoxia would augment these training adaptations. Thirty male well-trained academy rugby union and rugby league players (18.4 ± 1.5 years, 1.83 ± 0.07 m, 88.1 ± 8.9 kg) participated in this single-blind repeated sprint training study. Participants completed 12 sessions of repeated sprint training (10 × 6 s, 30 s recovery) over 4 weeks in either hypoxia (13% FiO₂) or normoxia (21% FiO₂). Pretraining and post-training, participants completed sports specific endurance and sprint field tests and a 10 × 6 s RSA test on a non-motorised treadmill while measuring speed, heart rate, capillary blood lactate, muscle and cerebral deoxygenation and respiratory measures. Yo-Yo Intermittent Recovery Level 1 test performance improved after RS training in both groups, but gains were significantly greater in the hypoxic (33 ± 12%) than the normoxic group (14 ± 10%, prepeated aerobic high intensity workout than an equivalent normoxic training. Performance gains are evident in the short term (4 weeks), a period similar to a preseason training block.

  13. Specific Measurement of Tethered Running Kinetics and its Relationship to Repeated Sprint Ability

    Directory of Open Access Journals (Sweden)

    Sousa Filipe

    2015-12-01

    Full Text Available Repeated sprint ability has been widely studied by researchers, however, analysis of the relationship between most kinetic variables and the effect of fatigue is still an ongoing process. To search for the best biomechanical parameter to evaluate repeated sprint ability, several kinetic variables were measured in a tethered field running test and compared regarding their sensitivity to fatigue and correlation with time trials in a free running condition. Nine male sprint runners (best average times: 100 m = 10.45 ± 0.07 s; 200 m = 21.36 ± 0.17 s; 400 m = 47.35 ± 1.09 s completed two test sessions on a synthetic track. Each session consisted of six 35 m sprints interspersed by 10 s rest under tethered field running or free running conditions. Force, power, work, an impulse and a rate of force development were all directly measured using the sensors of a new tethered running apparatus, and a one-way ANOVA with Scheffé post-hoc test used to verify differences between sprints (p < 0.05. Pearson product-moment correlation measured the relationship between mechanical variables and free running performance. A total impulse, the rate of force development and maximum force did not show significant differences for most sprints. These three variables presented low to moderate correlations with free running performance (r between 0.01 and -0.35. Maximum and mean power presented the strongest correlations with free running performance (r = -0.71 and -0.76, respectively; p < 0.001, followed by mean force (r = -0.61; p < 0.001 and total work (r = -0.50; p < 0.001. It was concluded that under a severe work-to-rest ratio condition, power variables were better suited to evaluating repeated sprint ability than the other studied variables.

  14. Effects of sodium phosphate and caffeine loading on repeated-sprint ability.

    Science.gov (United States)

    Buck, Christopher; Guelfi, Kym; Dawson, Brian; McNaughton, Lars; Wallman, Karen

    2015-01-01

    The effects of sodium phosphate and caffeine supplementation were assessed on repeated-sprint ability. Using a randomised, double-blind, Latin-square design, 12 female, team-sport players participated in four trials: (1) sodium phosphate and caffeine, (2) sodium phosphate and placebo (for caffeine), (3) caffeine and placebo (for sodium phosphate) and (4) placebo (for sodium phosphate and caffeine), with ~21 days separating each trial. After each trial, participants performed a simulated team-game circuit (4 × 15 min quarters) with 6 × 20-m repeated-sprints performed once before (Set 1), at half-time (Set 2), and after end (Set 3). Total sprint times were faster after sodium phosphate and caffeine supplementation compared with placebo (Set 1: P = 0.003; Set 2: d = -0.51; Set 3: P sprint times were faster after sodium phosphate supplementation compared with placebo (Set 1: d = -0.52; Set 3: d = -0.58). Best sprint results were faster after sodium phosphate and caffeine supplementation compared with placebo (Set 3: P = 0.007, d = -0.90) and caffeine (Set 3: P = 0.024, d = -0.73). Best sprint times were also faster after sodium phosphate supplementation compared with placebo (d = -0.54 to -0.61 for all sets). Sodium phosphate and combined sodium phosphate and caffeine loading improved repeated-sprint ability.

  15. Specific Measurement of Tethered Running Kinetics and its Relationship to Repeated Sprint Ability.

    Science.gov (United States)

    Sousa, Filipe; Dos Reis, Ivan; Ribeiro, Luiz; Martins, Luiz; Gobatto, Claudio

    2015-12-22

    Repeated sprint ability has been widely studied by researchers, however, analysis of the relationship between most kinetic variables and the effect of fatigue is still an ongoing process. To search for the best biomechanical parameter to evaluate repeated sprint ability, several kinetic variables were measured in a tethered field running test and compared regarding their sensitivity to fatigue and correlation with time trials in a free running condition. Nine male sprint runners (best average times: 100 m = 10.45 ± 0.07 s; 200 m = 21.36 ± 0.17 s; 400 m = 47.35 ± 1.09 s) completed two test sessions on a synthetic track. Each session consisted of six 35 m sprints interspersed by 10 s rest under tethered field running or free running conditions. Force, power, work, an impulse and a rate of force development were all directly measured using the sensors of a new tethered running apparatus, and a one-way ANOVA with Scheffé post-hoc test used to verify differences between sprints (p sprints. These three variables presented low to moderate correlations with free running performance (r between 0.01 and -0.35). Maximum and mean power presented the strongest correlations with free running performance (r = -0.71 and -0.76, respectively; p sprint ability than the other studied variables.

  16. THE RELATIONSHIP BETWEEN AEROBIC POWER AND REPEATED SPRINT ABILITY IN YOUNG SOCCER PLAYERS WITH DIFFERENT LEVELS OF VO2 MAX

    Directory of Open Access Journals (Sweden)

    Rostam Alizadeh

    2010-06-01

    Full Text Available In some team sports such as soccer which is interval, athletes need to prepare themselves immediatelyfor the next activity. Therefore it is very important to have enough information on characteristics of recovery phase and quick recovery to the first situation and to have the minimum speed reduction. The purpose of this study was to determine the relationship between aerobic power and repeated sprint ability (RSA or decrementindex in young soccer players in three different levels of Vo2max. Methods: For this reason 41 volunteers were divided in to three groups with different levels of Vo2max ml.kg-1.min-1 low 37.22 ± 2.3 (n= 18, age 17.1 ± 0.9 year, height 170.6 ± 0.76 cm, weight 67.1 ± 5.05 kg medium 46.46± 1.97 ml.kg-1.min-1 (n= 13, age 17.6± 0.76year, height 173.8 ± 4.84 cm, weight 65.9 ± 4.92 kg and high 55.63 ± 1.52 ml.kg-1.min-1 (n=10, age 17.4 ±0.69 year, height 177 ± 3.23 cm, weight 71.4 ± 3.94 kg. To determine Vo2max a graded exercise test until volitional exhaustion on treadmill was used, and also RAST was used to measure RSA. The lactate accumulation was measured before and after RSA protocol. Pearson's correlation was used to determine the correlation between the aerobic power and RSA. The results indicated that there are significant relationship between Vo2max anddecremental index in low Vo2max group (r= 0.86, p= 0.001, no significant relationship medium Vo2max group (r= 0.14, p= 0.63 and negative significant relationship in high Vo2max group (r= - 0.64, p= 0.04. There are no significant relationship between Lactate accumulation and decremental index in medium (r= 0.005, p= 0.98 and high Vo2max groups (r=0.27, p= 0.45. Discussion: It is possible that the recovery of inter muscular resources relates to aerobic ability, but there are other factors effective in RSA rather than Vo2max and Lactate accumulation. The current study showed a normal curved relationship between Vo2max and RSA.

  17. Effects of Sprint Training With and Without Weighted Vest on Speed and Repeated Sprint Ability in Male Soccer Players.

    Science.gov (United States)

    Rey, Ezequiel; Padrón-Cabo, Alexis; Fernández-Penedo, Diego

    2016-11-16

    The purpose of this study was to assess the effect resisted sprint training using weighted vests (WV) compared with unresisted sprint training (US) on physical fitness (countermovement jump, 10 m sprint, 30 m sprint and repeated sprint ability (RSA)) in amateur male soccer players. 19 soccer players (age: 23.7±4.5 years; height: 178.3±5.8 cm; body mass: 72.9±5.2 kg) were randomly assigned to a WV (n= 10) or a US (n= 9) group. The intervention program had to be carried out 2 times a week over 6 weeks. The only difference between the two interventions was that the WV group performed all the sprints with an additional weight of 18.9% ± 2.1% of body mass. Within-group analysis showed significant improvements (psprint performance from pretest to post-test in WB (+9.42% and +6.04%) and CTU (+10.87% and +5.10%). Players in both WV and US also showed significant enhancements in RSA average time, fastest time, and total time from pretest to posttest. Percentage changes in 30 m sprint performance, for both groups combined, had a very large correlation with percentage changes in average time of RSA. In the between-groups analysis, there were no differences between the sprint training groups (WV vs US) in any variable. In conclusion, the findings of this study indicate that both sprint training methods used seem to be effective to improve soccer related performance measures, and could be beneficial to players and coaches in field settings.

  18. Repeated Sprint Ability in Young Basketball Players (Part 2): The Chronic Effects of Multidirection and of One Change of Direction Are Comparable in Terms of Physiological and Performance Responses

    OpenAIRE

    Attene, Giuseppe; Nikolaidis, Pantelis T.; Bragazzi, Nicola L.; Dello Iacono, Antonio; Pizzolato, Fabio; Zagatto, Alessandro M.; Dal Pupo, Juliano; Oggianu, Marcello; Migliaccio, Gian M.; Mannucci Pacini, Elena; Padulo, Johnny

    2016-01-01

    The aim of this study was to examine the effects of a 5-week training program, consisting of repeated 30-m sprints, on two repeated sprint ability (RSA) test formats: one with one change of direction (RSA) and the other with multiple changes of direction (RSM). Thirty-six young male and female basketball players (age 16.1 ± 0.9 years), divided into two experimental groups, were tested for RSA, RSM, squat jump, counter-movement jump, and the Yo-Yo Intermittent Recovery-Level-1 (Yo-Yo IR1) test...

  19. Repeated sprint ability and stride kinematics are altered following an official match in national-level basketball players.

    Science.gov (United States)

    Delextrat, A; Baliqi, F; Clarke, N

    2013-04-01

    The aim of the study was to investigate the effects of playing an official national-level basketball match on repeated sprint ability (RSA) and stride kinematics. Nine male starting basketball players (22.8±2.2 years old, 191.3±5.8 cm, 88±10.3 kg, 12.3±4.6% body fat) volunteered to take part. Six repetitions of maximal 4-s sprints were performed on a non-motorised treadmill, separated by 21-s of passive recovery, before and immediately after playing an official match. Fluid loss, playing time, and the frequencies of the main match activities were recorded. The peak, mean, and performance decrement for average and maximal speed, acceleration, power, vertical and horizontal forces, and stride parameters were calculated over the six sprints. Differences between pre- and post-match were assessed by student t-tests. Significant differences between pre- and post-tests were observed in mean speed (-3.3%), peak and mean horizontal forces (-4.3% and -17.4%), peak and mean vertical forces (-3.4% and -3.7%), contact time (+7.3%), stride duration (+4.6%) and stride frequency (-4.0%), (Psprint, jump and shuffle frequencies (Prepeated sprint ability depends on the specific activities performed, and that replacing fluid loss through sweating during a match is crucial.

  20. Improvement of Repeated-Sprint Ability and Horizontal-Jumping Performance in Elite Young Basketball Players With Low-Volume Repeated-Maximal-Power Training.

    Science.gov (United States)

    Gonzalo-Skok, Oliver; Tous-Fajardo, Julio; Arjol-Serrano, José Luis; Suarez-Arrones, Luis; Casajús, José Antonio; Mendez-Villanueva, Alberto

    2016-05-01

    To examine the effects of a low-volume repeated-power-ability (RPA) training program on repeated-sprint and change-of- direction (COD) ability and functional jumping performance. Twenty-two male elite young basketball players (age 16.2 ± 1.2 y, height 190.0 ± 10.0 cm, body mass 82.9 ± 10.1 kg) were randomly assigned either to an RPA-training group (n = 11) or a control group (n = 11). RPA training consisted of leg-press exercise, twice a week for 6 wk, of 1 or 2 blocks of 5 sets × 5 repetitions with 20 s of passive recovery between sets and 3 min between blocks with the load that maximized power output. Before and after training, performance was assessed by a repeated-sprint-ability (RSA) test, a repeated-COD-ability test, a hop for distance, and a drop jump followed by tests of a double unilateral hop with the right and left legs. Within-group and between-groups differences showed substantial improvements in slowest (RSAs) and mean time (RSAm) on RSA; best, slowest and mean time on repeated-COD ability; and unilateral right and left hop in the RPA group in comparison with control. While best time on RSA showed no improvement in any group, there was a large relationship (r = .68, 90% CI .43;.84) between the relative decrement in RSAm and RSAs, suggesting better sprint maintenance with RPA training. The relative improvements in best and mean repeated-COD ability were very largely correlated (r = .89, 90% CI .77;.94). Six weeks of lowvolume (4-14 min/wk) RPA training improved several physical-fitness tests in basketball players.

  1. Effect of between-set recovery durations on repeated sprint ability in young soccer players.

    Science.gov (United States)

    Selmi, M A; Haj, Sassi R; Haj, Yahmed M; Moalla, W; Elloumi, M

    2016-06-01

    The purposes of this study were to examine the effect of between-set recovery duration on physiological responses (heart rate and blood lactate), rating of perceived exertion (RPE) and performance indices of repeated sprint sets (RSS) and to investigate their relationship with aerobic power. Twenty-four young male soccer players (age: 17.4 ± 0.32 years) performed three randomized RSS protocols consisting of 2 sets of 5x20 m with 15 s recovery between sprints and 1 min (RSS1), 2 min (RSS2) and 4 min (RSS4) between sets, and a multi-stage aerobic track test to estimate VO2max. Results showed that in contrast to RSS2 and RSS4, RSS1 leads to a large decline in performance expressed as the sum of sprint times (34.0±1.0 s, 34.0±1.1s and 34.6±1.1s, respectively) and a significant increase of both mean heart rate (124.0±9.7 bpm, 112.5±6.7 bpm and 137.3±12.4, respectively) and RPE (3.2±1.5, 3.4±1.2 and 6.3±1.4, respectively) with no change in blood lactate and peak HR between the three rest conditions. No significant correlations were obtained between estimated VO2max and any of the indices of the three RSS protocols. In conclusion, 1 min of recovery between sets is sufficient to ensure a significant decrease in performance in the second set, while 2 min and 4 min of recovery were long enough to provide maintenance of high intensity work in the second set. These findings would be useful for coaches and sport scientists when attempting to assess repeated sprint abilities, allowing coaches to accurately define the intended training goals in young soccer players.

  2. Effect of between-set recovery durations on repeated sprint ability in young soccer players

    Directory of Open Access Journals (Sweden)

    MA Selmi

    2016-04-01

    Full Text Available The purposes of this study were to examine the effect of between-set recovery duration on physiological responses (heart rate and blood lactate, rating of perceived exertion (RPE and performance indices of repeated sprint sets (RSS and to investigate their relationship with aerobic power. Twenty-four young male soccer players (age: 17.4 ± 0.32 years performed three randomized RSS protocols consisting of 2 sets of 5x20 m with 15 s recovery between sprints and 1 min (RSS1, 2 min (RSS2 and 4 min (RSS4 between sets, and a multi-stage aerobic track test to estimate VO2max. Results showed that in contrast to RSS2 and RSS4, RSS1 leads to a large decline in performance expressed as the sum of sprint times (34.0±1.0 s, 34.0±1.1s and 34.6±1.1s, respectively and a significant increase of both mean heart rate (124.0±9.7 bpm, 112.5±6.7 bpm and 137.3±12.4, respectively and RPE (3.2±1.5, 3.4±1.2 and 6.3±1.4, respectively with no change in blood lactate and peak HR between the three rest conditions. No significant correlations were obtained between estimated VO2max and any of the indices of the three RSS protocols. In conclusion, 1 min of recovery between sets is sufficient to ensure a significant decrease in performance in the second set, while 2 min and 4 min of recovery were long enough to provide maintenance of high intensity work in the second set. These findings would be useful for coaches and sport scientists when attempting to assess repeated sprint abilities, allowing coaches to accurately define the intended training goals in young soccer players.

  3. Relationships between anthropometric measures and athletic performance, with special reference to repeated-sprint ability, in the Qatar national soccer team.

    Science.gov (United States)

    Brocherie, Franck; Girard, Olivier; Forchino, Fabricio; Al Haddad, Hani; Dos Santos, Gilvan A; Millet, Grégoire P

    2014-01-01

    The aim of this study was to determine potential relationships between anthropometric parameters and athletic performance with special consideration to repeated-sprint ability (RSA). Sixteen players of the senior male Qatar national soccer team performed a series of anthropometric and physical tests including countermovement jumps without (CMJ) and with free arms (CMJwA), straight-line 20 m sprint, RSA (6 × 35 m with 10 s recovery) and incremental field test. Significant (P sprinting times and r = 0.54 for maximal sprinting speed) with the exception of the sprint decrement score (Sdec). The sum of six skinfolds and adipose mass index were largely correlated with Sdec (r = 0.68, P 0.05, respectively) or any standard athletic tests. Multiple regression analyses indicated that muscular cross-sectional area for mid-thigh, adipose index, straight-line 20 m time, maximal sprinting speed and CMJwA are the strongest predictors of Sdec (r(2) = 0.89) and TT (r(2) = 0.95) during our RSA test. In the Qatar national soccer team, players' power-related qualities and RSA are associated with a high muscular profile and a low adiposity. This supports the relevance of explosive power for the soccer players and the larger importance of neuromuscular qualities determining the RSA.

  4. Effects of Four Weeks of β-Alanine Supplementation on Repeated Sprint Ability in Water Polo Players.

    Science.gov (United States)

    Brisola, Gabriel Motta Pinheiro; Artioli, Guilherme Giannini; Papoti, Marcelo; Zagatto, Alessandro Moura

    2016-01-01

    The purpose of this study was to investigate the effect of four weeks of β-alanine supplementation on repeated sprint ability in water polo players. Twenty-two male water polo players participated in the study, divided randomly into two homogeneous groups (placebo and β-alanine groups). The study design was double-blind, parallel and placebo controlled. Before and after the supplementation period (28 days), the athletes performed two specific repeated sprint ability tests interspaced by a 30-minute swimming test. Participants received 4.8g∙day-1 of the supplement (dextrose or β-alanine) on the first 10 days and 6.4g∙day-1 on the final 18 days. There was no significant group-time interaction for any variable. The qualitative inference for substantial changes demonstrated a likely beneficial effect in the β-alanine group (β-alanine vs placebo) for mean time (6.6±0.4s vs 6.7±0.4s; 81% likely beneficial), worst time (6.9±0.5s vs 7.1±0.5s; 78% likely beneficial) and total time (39.3±2.5s vs 40.4±2.5s; 81% likely beneficial) in the first repeated sprint ability set and for worst time (7.2±0.6s vs 7.5±0.6s; 57% possible beneficial) in the second repeated sprint ability set. Further, was found substantial change for total time for both repeated sprint ability tests (80.8±5.7s vs 83.4±5.6s; 52% possible beneficial). To conclude, four weeks of β-alanine supplementation had a likely beneficial effect in the first set of repeated sprint ability tests and a possible beneficial effect for worst time in the second set performed in a specific protocol in water polo players.

  5. Effects of Four Weeks of β-Alanine Supplementation on Repeated Sprint Ability in Water Polo Players

    Science.gov (United States)

    Brisola, Gabriel Motta Pinheiro; Artioli, Guilherme Giannini; Papoti, Marcelo; Zagatto, Alessandro Moura

    2016-01-01

    The purpose of this study was to investigate the effect of four weeks of β-alanine supplementation on repeated sprint ability in water polo players. Twenty-two male water polo players participated in the study, divided randomly into two homogeneous groups (placebo and β-alanine groups). The study design was double-blind, parallel and placebo controlled. Before and after the supplementation period (28 days), the athletes performed two specific repeated sprint ability tests interspaced by a 30-minute swimming test. Participants received 4.8g∙day-1 of the supplement (dextrose or β-alanine) on the first 10 days and 6.4g∙day-1 on the final 18 days. There was no significant group-time interaction for any variable. The qualitative inference for substantial changes demonstrated a likely beneficial effect in the β-alanine group (β-alanine vs placebo) for mean time (6.6±0.4s vs 6.7±0.4s; 81% likely beneficial), worst time (6.9±0.5s vs 7.1±0.5s; 78% likely beneficial) and total time (39.3±2.5s vs 40.4±2.5s; 81% likely beneficial) in the first repeated sprint ability set and for worst time (7.2±0.6s vs 7.5±0.6s; 57% possible beneficial) in the second repeated sprint ability set. Further, was found substantial change for total time for both repeated sprint ability tests (80.8±5.7s vs 83.4±5.6s; 52% possible beneficial). To conclude, four weeks of β-alanine supplementation had a likely beneficial effect in the first set of repeated sprint ability tests and a possible beneficial effect for worst time in the second set performed in a specific protocol in water polo players. PMID:27930743

  6. Reliability characteristics and applicability of a repeated sprint ability test in male young soccer players.

    Science.gov (United States)

    Castagna, Carlo; Francini, Lorenzo; Krustrup, Peter; Fenarnandes-da-Silva, Juliano; Póvoas, Susana C A; Bernardini, Andrea; D'Ottavio, Stefano

    2017-07-28

    The aim of this study was to examine the usefulness and reliability characteristics of a repeated sprint ability test considering 5 line sprints of 30-m interspersed with 30-s of active recovery in non-elite outfield young male soccer players. Twenty-six (age 14.9±1.2 years, height 1.72±0.12 cm, body mass 62.2±5.1 kg) players were tested 48 hours and 7 days apart for 5x30-m performance over 5 trials (T1-T5). Short- (T1-T2) and long-term reliability (T1-T3-T4-T5) were assessed with Intraclass Correlation Coefficient (ICC) and with typical error for measurement (TEM). Short- and long-term reliability ICCs and TEMs for total sprint time and best sprint performance were nearly perfect and satisfactory, respectively. Usefulness (as smallest worthwhile change and TEM ratio) resulted acceptable (i.e =1) and good (i.e >1) for total sprint time and best sprint performance, respectively. The present study revealed that the 5x30-m sprint test is a reliable field test in the short and long-term when the sum of sprint times and the best sprint performance are considered as outcome variables. Sprint performance decrements variables showed large variability across trials.

  7. Effects of a small-sided game-based training programme on repeated sprint and change of direction abilities in recreationally-trained football players.

    Science.gov (United States)

    Bujalance-Moreno, Pascual; García-Pinillos, Felipe; Latorre-Román, Pedro Á

    2017-02-21

    To examine the effects of 6-week periodized small-sided game (SSG) training intervention on change of direction [COD], sprint and repeated sprint ability [RSA] in recreational male football players. Twenty-three young football players (age: 20.86 years) were randomized in a control group (n = 11) and an experimental group (n = 12). The SSG programme was included in the experimental group's training sessions. The players completed two variations of a SSG (i.e. 2 vs. 2 and 4 vs. 4 players) during intervention. To examine the changes in physical performance after the 6-week periodized SSG training intervention, all players were tested 6 weeks apart (i.e. pre-test and post-test) in sprint, COD ability test, and RSA shuttle test. A 2x2 ANOVA showed that 6-week SSG training intervention induced significant improvements (P0.7) in COD ability test, and variables related to both sprint test and RSA in the experimental group, whereas the control group remained unchanged (P≥0.05, ESsprint in recreationally trained football players.

  8. Effects of in-season short-term aerobic and high-intensity interval training program on repeated sprint ability and jump performance in handball players.

    Science.gov (United States)

    Hermassi, Souhail; Ingebrigtsen, Jørgen; Schwesig, René; Fieseler, Georg; Delank, Karl S; Chamari, Karim; Shephard, Roy J; Chelly, Mohamed S

    2016-11-16

    This study examined the effects of a 7-week in-season aerobic and high-intensity interval-training program on performance tests linked to successful handball play (e.g., repeated sprint and jumping ability). Thirty participants (age 17.0 ± 1.2 years, body mass 81.1 ± 3.4 kg, height 1.82± 0.07 m) performed a Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IR1), a squat (SJ) and a countermovement jump test (CMJ), as well as a repeated sprint ability test (RSA). From this, maximal aerobic speed (MAS, reached at the end of the Yo-Yo IR1), jumping ability, best time in a single sprint trial (RSAbest), total time (RSATT) and the performance decrement (RSAdec) during all sprints were calculated. Later, subjects were randomly assigned to a control group (CG; n=15) performing their normal training schedule (5 weekly sessions of ~90 min of handball training) or an experimental group (EG; n=15). The EG performed two 30 min sessions per week of high-intensity aerobic exercises at 100-130% of MAS in addition to their normal training schedule. Demonstrated a significant improvement in MAS (d=4.1), RSAbest (d=1.9), RSATT (d=1.5) and RSAdec (d=2.3) after the training period. Also, significant interaction effects (time x group) were found for all parameters as the EG significantly improved performances in all tests after training. The greatest interaction effects were observed in MAS (2=0.811) and CMJ (2=0.759). No relevant changes in test performances were found in the CG (mean d=-0.02). These results indicate that individually speed controlled aerobic and interval training is effective for improving specific handball performance.

  9. Evaluation of the running-based anaerobic sprint test as a measure of repeated sprint ability in collegiate-level soccer players.

    Science.gov (United States)

    Keir, Daniel A; Thériault, Francis; Serresse, Olivier

    2013-06-01

    Repeated sprint ability (RSA) refers to an individual's ability to perform maximal sprints of short duration in succession with little recovery between sprints. The running-based anaerobic sprint test (RAST) has been adapted from the Wingate anaerobic test (WAnT) protocol as a tool to assess RSA and anaerobic power. The purpose of this study was to evaluate the relationship between performance variables and physiological responses obtained during the RAST and the WAnT using 8 collegiate-level soccer players. Participants performed a single trial of both the WAnT and the RAST. Breath-by-breath gas exchange was monitored throughout each trial, and blood lactate (BL) measures were recorded postexercise. The oxygen uptake (VO2) profile suggested that the RAST required greater contributions from aerobic metabolism although there was no difference in VO2peak (p < 0.05). Peak BL values were also similar between the RAST and the WAnT (p < 0.05). Neither peak physiological values nor performance variables (peak and mean power) were significantly correlated between protocols. The weak association in physiological responses indicates that different combinations of metabolic contributions exist between protocols, suggesting that individual performances on each test are not related in collegiate soccer players. Further studies on these relationships with players of other competitive levels and team sport athletes are warranted.

  10. Six weeks of β-alanine supplementation did not enhance repeated-sprint ability or technical performances in young elite basketball players.

    Science.gov (United States)

    Milioni, Fabio; Redkva, Paulo E; Barbieri, Fabio A; Zagatto, Alessandro M

    2017-06-01

    Supplementation with β-alanine plays an important role as a precursor of carnosine, the most effective intramuscular buffer, and has been seen as a potential ergogenic aid, especially for high-intensity modalities such as basketball. Thus, the aim of the present study was to investigate the effects of 6 weeks of β-alanine supplementation on repeated sprint ability (RSA) and technical performances in young elite Brazilian basketball players. In total, 27 young basketball players (17±1 years) were randomized into a β-alanine group (Gβ - 6.4 g day(-1) of β-alanine) and a placebo group (GP - 6.4 g day(-1) of dextrose). Before and after the supplementation period the athletes performed a RSA test composed of ten 30 m sprints with two 180° changes of direction interspaced by 30 s of recovery. During the recovery period (i.e., after the sprints) the athletes performed a countermovement jump (CMJ) and a set of three free throws. After 48 h they performed a Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1). Both groups increased the distance covered in the Yo-Yo IR1 after the supplementation period ( p = 0.001). On the other hand, both groups presented impairment in RSA time-performance (total time, best time, and mean time, p ≤ 0.04), while no significant changes were observed for technical task performances (i.e., CMJ and free throws) ( p ≥ 0.07). No between-group interactions were observed for any variable measured ( p ≥ 0.31). Thus, 6 weeks of β-alanine supplementation did not improve RSA or technical performances in young elite basketball players.

  11. Relationship between aerobic fitness and repeated sprint ability in soccer: protocol effect. DOI: 10.5007/1980-0037.2011v13n2p111

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    Leandro Teixeira Floriano

    2011-03-01

    Full Text Available The aim of this study was to evaluate the association between physiological variables related to physical fitness determined by continuous straight running on a treadmill (peak velocity on treadmill: PVTRE, maximum oxygen uptake: VO2max, minimum velocity needed to reach VO2max: vVO2max, and velocity at the anaerobic threshold: vAT and intermittent running with directional changes (peak velocity: PV and repeated sprint ability (RSA in soccer players. Twenty-nine athletes (17.9 ± 1.0 years, 178.7 ± 5.2 cm, 73.6 ± 6.7 kg, and 11.1 ± 1.3% body fat performed the following tests on different days: 1 incremental protocol on a treadmill to determine PVTRE, VO2max, vVO2max, and vAT; 2 incremental intermittent running test to determine PV, and 3 Bangsbo test to evaluate RSA and to determine the mean time (MT, fastest time (FT, and fatigue index (FI. Pearson’s correlation coefficient was used and a level of significance of 5% was adopted. PV obtained in the intermittent running test showed a higher correlation with MT and FT of the RSA test (r = -0.70, p 0.05 and PVTRE (r = -0.42, p 0.05 determined by straight running on a treadmill. In conclusion, the relationship between physical fitness and RSA depends on the type of protocol (continuous line running vs. intermittent with directional changes and the aerobic index used (capacity vs. power.

  12. Beta-Alanine Supplementation Improves Throwing Velocities in Repeated Sprint Ability and 200-m Swimming Performance in Young Water Polo Players.

    Science.gov (United States)

    Claus, Gabriel Machado; Redkva, Paulo Eduardo; Brisola, Gabriel Mota Pinheiro; Malta, Elvis Sousa; de Araujo Bonetti de Poli, Rodrigo; Miyagi, Willian Eiji; Zagatto, Alessandro Moura

    2017-05-01

    The purpose of this study was to investigate the effects of beta-alanine supplementation on specific tests for water polo. Fifteen young water polo players (16 ± 2 years) underwent a 200-m swimming performance, repeated-sprint ability test (RSA) with free throw (shooting), and 30-s maximal tethered eggbeater kicks. Participants were randomly allocated into two groups (placebo × beta-alanine) and supplemented with 6.4g∙day(-1)of beta-alanine or a placebo for six weeks. The mean and total RSA times, the magnitude based inference analysis showed a likely beneficial effect for beta-alanine supplementation (both). The ball velocity measured in the throwing performance after each sprint in the RSA presented a very like beneficial inference in the beta-alanine group for mean (96.4%) and percentage decrement of ball velocity (92.5%, likely beneficial). Furthermore, the percentage change for mean ball velocity was different between groups (beta-alanine=+2.5% and placebo=-3.5%; p = .034). In the 30-s maximal tethered eggbeater kicks the placebo group presented decreased peak force, mean force, and fatigue index, while the beta-alanine group maintained performance in mean force (44.1%, possibly beneficial), only presenting decreases in peak force. The 200-m swimming performance showed a possibly beneficial effect (68.7%). Six weeks of beta-alanine supplementation was effective for improving ball velocity shooting in the RSA, maintaining performance in the 30-s test, and providing possibly beneficial effects in the 200-m swimming performance.

  13. Effects of sodium phosphate and caffeine ingestion on repeated-sprint ability in male athletes.

    Science.gov (United States)

    Kopec, Benjamin J; Dawson, Brian T; Buck, Christopher; Wallman, Karen E

    2016-03-01

    To assess the effects of sodium phosphate (SP) and caffeine supplementation on repeated-sprint performance. Randomized, double-blind, Latin-square design. Eleven team-sport males participated in four trials: (1) SP (50mgkg(-1) of free fat-mass daily for six days) and caffeine (6mgkg(-1) ingested 1h before exercise); SP+C, (2) SP and placebo (for caffeine), (3) caffeine and placebo (for SP) and (4) placebo (for SP and caffeine). After loading, participants performed a simulated team-game circuit (STGC) consisting of 2×30min halves, with 6×20-m repeated-sprint sets performed at the start, half-time and end of the STGC. There were no interaction effects between trials for first-sprint (FS), best-sprint (BS) or total-sprint (TS) times (p>0.05). However, SP resulted in the fastest times for all sprints, as supported by moderate to large effect sizes (ES; d=0.51-0.83) and 'likely' to 'very likely' chances of benefit, compared with placebo. Compared with caffeine, SP resulted in 'possible' to 'likely' chances of benefit for FS, BS and TS for numerous sets and a 'possible' chance of benefit compared with SP+C for BS (set 2). Compared with placebo, SP+C resulted in moderate ES (d=0.50-0.62) and 'possible' to 'likely' benefit for numerous sprints, while caffeine resulted in a moderate ES (d=0.63; FS: set 3) and 'likely' chances of benefit for a number of sets. While not significant, ES and qualitative analysis results suggest that SP supplementation may improve repeated-sprint performance when compared with placebo. Copyright © 2015 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  14. Effect of ischemic preconditioning on repeated sprint ability in team sport athletes.

    Science.gov (United States)

    Gibson, Neil; Mahony, Ben; Tracey, Claire; Fawkner, Samantha; Murray, Andrew

    2015-01-01

    This study investigated whether ischemic preconditioning (IPC) in a trained population affected repeated sprint performance. A secondary aim was to assess responses according to gender. Sixteen (nine females and seven males) well trained team sport athletes took part in a randomised crossover study design. Participants underwent an IPC and placebo treatment involving three periods of 5 min occlusion applied unilaterally (3 × 5 min occlusion to each leg) at either 220 mmHg or 50 mmHg. Each period of occlusion was followed by 5 min reperfusion. Following treatment 5 × 6 s maximal effort sprints were undertaken on a cycle ergometer against 7.5% body mass, each interspersed by 24 s recovery. Measured parameters included peak power, total power, percentage decrement, post-exercise blood lactate and ratings of perceived exertion. Nor within subject main effect for IPC was observed, neither was there an interaction effect with gender. Effect sizes were trivial (ES repeated sprint performance. A lower blood lactate response in female participants following IPC may suggest improved blood flow through vasodilation.

  15. Effects of Three Different Resistance Training Frequencies on Jump, Sprint, and Repeated Sprint Ability Performance in Professional Futsal Players.

    Science.gov (United States)

    Paz-Franco, Adrián; Rey, Ezequiel; Barcala-Furelos, Roberto

    2017-02-21

    The aim of this study was to examine the effect of 3 different resistance training frequencies (one strength training session per week (1W), two strength training sessions per week (2W) or one strength training session every second week (0.5W)) on jump, sprint and repeated sprint performance (RSA) in professional futsal players. Thirty-five futsal players were randomized into 1 of 3 groups, the 1W group (n= 12), 2W group (n= 12), or the 0.5W group (n= 11). The players performed the same resistance training during 6 weeks and only training frequency differed between the groups. Within-group analysis showed significant improvements in jump (p≤0.001, Effect Size (ES)= 0.13-0.35), sprint (p≤0.001, ES= 0.48-0.71), and RSA (p≤0.01, ES= 0.22-0.63) from pretest to posttest in 1W and 2W. However, no significant (p>0.05) pre-post changes were observed for the 0.5W in any variable. In the between-groups analysis, significant better results were found in jump (p≤0.01), sprint (p≤0.01), and RSA performance (p≤0.01) in the 1W group and 2W group in comparison with 0.5W group. Also, jump (p≤0.05) and 5 m sprint (p≤0.05) performances was significantly better in the 2W group in comparison with 1W group. In conclusion, the current study showed that 6 weeks of RT one or two times per week in addition to typical futsal training, produced significant improvements in jump, sprint and RSA performance. Additionally, RT one every second week may be sufficient to maintain physical fitness in professional futsal players. This information may be useful for coaches when planning training contents during congested fixture schedules or in periods where the emphasis need to be put on other qualities and spend as little time as possible on maintaining or increasing physical performance.

  16. Laboratory Determinants of Repeated-Sprint and Sport-Specific-Technique Ability in World-Class Ice Sledge Hockey Players.

    Science.gov (United States)

    Baumgart, Julia Kathrin; Sandbakk, Øyvind

    2016-03-01

    To investigate on-ice repeated-sprint and sports-specific-technique abilities and the relationships to aerobic and anaerobic off-ice capacities in world-class ice sledge hockey players. Twelve Norwegian national team players performed 8 repeated maximal 30-m sprints and a sports-specific-technique test while upper-body poling on ice, followed by 4 maximal upper-body strength tests and 8-s peak power and 3-min peak aerobic-capacity (VO2peak) tests while ergometer poling. The fastest 30-m sprint time was 6.5 ± 0.4 s, the fastest initial 10-m split-time 2.9 ± 0.2 s, and the corresponding power output 212 ± 37 W. Average 30-m time during the 8 repeated sprints was 6.7 ± 0.4 s, and the sprint-time decrement was 4.3% ± 1.8%. Time to execute the sport-specific-technique test was 25.6 ± 2.7 s. Averaged 1-repetition-maximum strength of the 4 exercises correlated with the fastest 30-m sprint time (r = -.77), the fastest initial 10-m split time (r = -.72), the corresponding power output (r = .67), and the average 30-m sprint time (r = -.84) (all P sprint test correlated with the highest initial 10-m power (r = .83, P sprint time (r = -.68, P sprint-time decrement. All off-ice variables except VO2peak correlated with technique-test time (r = -.58 to .73, all P ability to sprint fast and rapid execution of a technically complex test, whereas mode-specific endurance capacity is particularly important for maintenance of sprint ability in ice sledge hockey.

  17. Longitudinal study of repeated sprint performance in youth soccer players of contrasting skeletal maturity status

    NARCIS (Netherlands)

    Valente-dos-Santos, Joao; Coelho-e-Silva, Manuel J.; Severino, Vitor; Duarte, Joao; Martins, Raul S.; Figueiredo, Antonio J.; Seabra, Andre T.; Philippaerts, Renaat M.; Cumming, Sean P.; Elferink-Gemser, Marije; Malina, Robert M.

    The purpose of the study was to evaluate the developmental changes in performance in a repeated-sprint ability (RSA) test in young soccer players of contrasting maturity status. A total of 83 regional level Portuguese youth soccer players, aged 11-13 years at baseline was assessed annually. Stature,

  18. Longitudinal study of repeated sprint performance in youth soccer players of contrasting maturity status

    NARCIS (Netherlands)

    V. Duarte; A. Seabra; A. Figueiredo; S. Cumming; R. Martins; R. Philippaerts; M. Coelho e Silva; J. Valente dos Santos; V. Severino; Marije Elferink-Gemser

    2012-01-01

    The purpose of the study was to evaluate the developmental changes in performance in a repeated-sprint ability (RSA) test in young soccer players of contrasting maturity status. A total of 83 regional level Portuguese youth soccer players, aged 11- 13 years at baseline was assessed annually.

  19. REPEATED SPRINT ABILITY IN PROFESSIONAL SOCCER vs. PROFESSIONAL FUTSAL PLAYERS [Capacidad de realizar esprints repetidos en jugadores profesionales de fútbol vs. Fútbol sala

    Directory of Open Access Journals (Sweden)

    V. Cuadrado-Peñafiel

    2014-10-01

    Full Text Available Purpose: To investigate the changes through repeated explosive effort sequences (20+20-m sprint with change of direction, jumping, metabolic response (lactate, as well as the relationship between these variables and fitness qualities (strength and endurance in professional futsal and soccer players. Methods: Male players (n =30, Twelve futsal and twenty soccer players completed three testing sessions. In the first session was measured VO2max on a motorized treadmill. In the second session was measured counter movement jump (CMJ and full squat RM in Smith Machine. Finally, in the third session six repeated-explosive effort sequences (RES was performed. Results: Similar values of lower limbs strength, CMJ height, LAC after RSA test and VO2max (95,12 vs. 94,73; 34,5 vs. 35,9; 13,65 vs. 14,33; 62,78 vs. 62,95 soccer vs. futsal respectively and significant differences when are analysed the loss of performance in velocity (total and between three first and three last and vertical jump height (2,67 vs. 4,4**; 1,28 vs. 2,1*; 2,88 vs. 6,1**; 9,71 vs. 14,3* soccer vs. futsal respectively. Conclusions: Professional futsal and soccer obtain significant differences in speed and vertical jump height (CMJ loss despite having similar values in squat, oxygen consumption, lactate after RSA test and CMJ height. Issue that could be attributed to the characteristics of the sport. This suggests that the volume should be increased oriented ability to perform repeated sprint actions over other type of training aimed at improving aerobic capacity especially at professional level.

  20. REPEATED SPRINT ABILITY IN PROFESSIONAL SOCCER vs. PROFESSIONAL FUTSAL PLAYERS [Capacidad de realizar esprints repetidos en jugadores profesionales de fútbol vs. Fútbol sala

    Directory of Open Access Journals (Sweden)

    V. Cuadrado-Peñafiel

    2014-10-01

    Full Text Available Purpose: To investigate the changes through repeated explosive effort sequences (20+20-m sprint with change of direction, jumping, metabolic response (lactate, as well as the relationship between these variables and fitness qualities (strength and endurance in professional futsal and soccer players. Methods: Male players (n =30, Twelve futsal and twenty soccer players completed three testing sessions. In the first session was measured VO2max on a motorized treadmill. In the second session was measured counter movement jump (CMJ and full squat RM in Smith Machine. Finally, in the third session six repeated-explosive effort sequences (RES was performed. Results: Similar values of lower limbs strength, CMJ height, LAC after RSA test and VO2max (95,12 vs. 94,73; 34,5 vs. 35,9; 13,65 vs. 14,33; 62,78 vs. 62,95 soccer vs. futsal respectively and significant differences when are analysed the loss of performance in velocity (total and between three first and three last and vertical jump height (2,67 vs. 4,4**; 1,28 vs. 2,1*; 2,88 vs. 6,1**; 9,71 vs. 14,3* soccer vs. futsal respectively. Conclusions: Professional futsal and soccer obtain significant differences in speed and vertical jump height (CMJ loss despite having similar values in squat, oxygen consumption, lactate after RSA test and CMJ height. Issue that could be attributed to the characteristics of the sport. This suggests that the volume should be increased oriented ability to perform repeated sprint actions over other type of training aimed at improving aerobic capacity especially at professional level.

  1. The optimal exercise to rest ratios in repeated sprint ability training in youth soccer players.

    Science.gov (United States)

    Ruscello, Bruno; Partipilo, Filippo; Pantanella, Laura; Esposito, Mario; D'Ottavio, Stefano

    2016-12-01

    The aim of this study was to investigate the applicability of three different exercise to rest ratios in RSA training in youth soccer players, applying those ones already adopted in adult players, when performing three different sprinting modes (straight, shuttle and sprinting with changing of direction). Eighteen young trained male soccer players (Height: 1.66±0.07 m; weight: 58.22±7.64 kg; BMI 19.37±3.42 kg·m-2; age:14 years) participated to the study. In order to compare the different values of the time recorded, a Fatigue Index (FI) was used. Recovery times among trials in the sets were administered according to the 1:5, 1:3; 1:2 exercise to rest ratio, respectively. Significant differences among trials within each set (Repeated Measures Anova; Psprinting modalities when applying the investigated exercise to rest ratios (Factorial Anova; between; P>0.05). The results of this study confirm that the exercise to rest ratios considered in this study might be suitable to design effective testing protocols and training sessions aimed at the development of the RSA in youth soccer players, keeping the performances in the speed domain (FI%< ≈7-8%) but inducing the fatigue processes sought with this kind of training method.

  2. Acute Responses to 10×15 m Repeated Sprint Ability Exercise in Adolescent Athletes: the Role of Change of Direction and Sport Specialization.

    Science.gov (United States)

    Nikolaidis, Pantelis Theodoros; Meletakos, Panagiotis; Tasiopoulos, Ioannis; Kostoulas, Ioannis; Ganavias, Panagiotis

    2016-06-01

    The repeated sprint ability (RSA) has been studied with protocols using distances longer than 20 m per sprint, whereas basketball players cover on average less than 20-meter distance per sprint during match. The aim of the present study was to examine the physiological impact of 10 × 15 m RSA test in straight-line (RSASL) or with change of direction (RSACOD), i.e. 10 × (7.5 + 7.5 m)) in young national level basketball players. Young basketball players (n = 11, age 17.1 (1.0) years, body mass 76 (6) kg, height 184 (4) cm, body mass index 22.6 (1.8) kgm(-2), sport experience 6.9 (2.7) years, mean (standard deviation)) and a control group consisting of high-school athletes (n = 7, 16.1 (0.7) years, 67 (6) kg, 177 (6) cm, 21.5 (1.0) kgm(-2), 7.7 (1.6) years, respectively) performed RSASL and RSACOD on a counter-balanced order. Sprints started every 30 seconds (active recovery) and there was 30 minutes break between RSA protocols; time variables were total time (TT), best time (BT) and fatigue index (FI). Countermovement jump (CMJ) was tested before and after each RSA protocol. Heart rate (HR) was continuously monitored during testing procedures. Compared with RSASL, TT and BT were worst in RSACOD (38.13 vs. 27.52 s and 3.67 vs. 2.66 s, P repeated measures ANOVA showed main effect of RSA on CMJ (pre-test vs. post-test, increase + 1.8 cm, P = 0.020, η(2) = 0.28); there was neither main effect of RSA protocols (RSASL vs. RSACOD +0.7 cm, P = 0.251, η(2) = 0.08) nor an interaction between pre-post measurements and RSA protocols (P = 0.578, η(2) = 0.02). Compared with RSASL, RSACOD induced higher mean and peak HR responses (175 vs 172 bpm, P < 0.001, and 185 vs 182 bpm, P = 0.002, respectively). No statistical difference was observed between basketball players and control group neither for TT (27.98 vs. 26.80 seconds, + 4.4%, P = 0.149) and BT (2.71 vs. 2.59 seconds, + 4.5%, P = 0.157) in RSASL nor for TT (38.55 vs. 37.47 seconds, + 2.9%, P = 0.169) and BT (3.70 vs. 3

  3. Repeated Sprint Ability in Young Basketball Players (Part 2): The Chronic Effects of Multidirection and of One Change of Direction Are Comparable in Terms of Physiological and Performance Responses.

    Science.gov (United States)

    Attene, Giuseppe; Nikolaidis, Pantelis T; Bragazzi, Nicola L; Dello Iacono, Antonio; Pizzolato, Fabio; Zagatto, Alessandro M; Dal Pupo, Juliano; Oggianu, Marcello; Migliaccio, Gian M; Mannucci Pacini, Elena; Padulo, Johnny

    2016-01-01

    The aim of this study was to examine the effects of a 5-week training program, consisting of repeated 30-m sprints, on two repeated sprint ability (RSA) test formats: one with one change of direction (RSA) and the other with multiple changes of direction (RSM). Thirty-six young male and female basketball players (age 16.1 ± 0.9 years), divided into two experimental groups, were tested for RSA, RSM, squat jump, counter-movement jump, and the Yo-Yo Intermittent Recovery-Level-1 (Yo-Yo IR1) test, before and after a 4-week training program and 1 week of tapering. One group performed 30-m sprints with one change of direction (RSA group, RSAG), whereas the other group performed multidirectional 30-m sprints (RSM group, RSMG). Both groups improved in all scores in the post-intervention measurements (P repeated 30-m sprints, either with one change of direction or multidirectional, induce similar physiological and performance responses in young basketball players, but have a different psycho-physiological impact.

  4. Reliability, usefulness, and validity of a repeated sprint and jump ability test.

    Science.gov (United States)

    Buchheit, Martin; Spencer, Matt; Ahmaidi, Said

    2010-03-01

    Two studies involving 122 handball players were conducted to assess the reliability, usefulness, and validity of a repeated shuttle-sprint and jump ability (RSSJA) test. The test consisted of 6x(2x12.5-m) sprints departing on 25 s, with a countermovement jump performed during recovery between sprints. For the reliability and usefulness study, 14 well-trained male handball players performed the RSSJA test 7 d apart. Reliability of the test variables was assessed by the typical error of measurement, expressed as a coefficient of variation (CV). The minimal changes likely to be "real" in sprint time and jump power were also calculated. For the validity study, players of seven teams (national to international levels, women and men) performed the RSSJA test. CV values for best and mean sprint time were 1.0% (90% CL, 0.7 to 1.6) and 1.0% (90% CL, 0.7 to 1.4). CV values for best and mean jump peak power were 1.7% (90% CL, 1.2 to 2.7) and 1.5% (90% CL, 1.1 to 2.5). The percent sprint and jump decrements were less reliable, with CVs of 22.3% (90% CL, 15.7 to 38.3) and 34.8% (90% CL, 24.2 to 61.8). Minimal changes likely to be "real" for mean sprint time and jumping peak power were -2.6% and 4.8%. Qualitative analysis revealed that the majority of between-team differences were rated as "almost certain" (ie, 100% probability that the true differences were meaningful) for mean sprint and jump performances. The RSSJA test is reliable and valid to assess repeated explosive effort sequences in team sports such as handball. Test results are likely to be representative of gender and competition level; thus the test could be used to discriminate across playing standards and monitor fitness levels.

  5. Significant Molecular and Systemic Adaptations after Repeated Sprint Training in Hypoxia

    Science.gov (United States)

    Faiss, Raphael; Léger, Bertrand; Vesin, Jean-Marc; Fournier, Pierre-Etienne; Eggel, Yan; Dériaz, Olivier; Millet, Grégoire P.

    2013-01-01

    While intermittent hypoxic training (IHT) has been reported to evoke cellular responses via hypoxia inducible factors (HIFs) but without substantial performance benefits in endurance athletes, we hypothesized that repeated sprint training in hypoxia could enhance repeated sprint ability (RSA) performed in normoxia via improved glycolysis and O2 utilization. 40 trained subjects completed 8 cycling repeated sprint sessions in hypoxia (RSH, 3000 m) or normoxia (RSN, 485 m). Before (Pre-) and after (Post-) training, muscular levels of selected mRNAs were analyzed from resting muscle biopsies and RSA tested until exhaustion (10-s sprint, work-to-rest ratio 1∶2) with muscle perfusion assessed by near-infrared spectroscopy. From Pre- to Post-, the average power output of all sprints in RSA was increased (psprints to exhaustion was increased in RSH (9.4±4.8 vs. 13.0±6.2 sprints, psprints throughout RSA test increased to a greater extent (prepeated sprint performance in RSH than in RSN with significant molecular adaptations and larger blood perfusion variations in active muscles. PMID:23437154

  6. Significant molecular and systemic adaptations after repeated sprint training in hypoxia.

    Directory of Open Access Journals (Sweden)

    Raphael Faiss

    Full Text Available While intermittent hypoxic training (IHT has been reported to evoke cellular responses via hypoxia inducible factors (HIFs but without substantial performance benefits in endurance athletes, we hypothesized that repeated sprint training in hypoxia could enhance repeated sprint ability (RSA performed in normoxia via improved glycolysis and O(2 utilization. 40 trained subjects completed 8 cycling repeated sprint sessions in hypoxia (RSH, 3000 m or normoxia (RSN, 485 m. Before (Pre- and after (Post- training, muscular levels of selected mRNAs were analyzed from resting muscle biopsies and RSA tested until exhaustion (10-s sprint, work-to-rest ratio 1:2 with muscle perfusion assessed by near-infrared spectroscopy. From Pre- to Post-, the average power output of all sprints in RSA was increased (p<0.01 to the same extent (6% vs 7%, NS in RSH and in RSN but the number of sprints to exhaustion was increased in RSH (9.4±4.8 vs. 13.0±6.2 sprints, p<0.01 but not in RSN (9.3±4.2 vs. 8.9±3.5. mRNA concentrations of HIF-1α (+55%, carbonic anhydrase III (+35% and monocarboxylate transporter-4 (+20% were augmented (p<0.05 whereas mitochondrial transcription factor A (-40%, peroxisome proliferator-activated receptor gamma coactivator 1α (-23% and monocarboxylate transporter-1 (-36% were decreased (p<0.01 in RSH only. Besides, the changes in total hemoglobin variations (Δ[tHb] during sprints throughout RSA test increased to a greater extent (p<0.01 in RSH. Our findings show larger improvement in repeated sprint performance in RSH than in RSN with significant molecular adaptations and larger blood perfusion variations in active muscles.

  7. A passive heat maintenance strategy implemented during a simulated half-time improves lower body power output and repeated sprint ability in professional Rugby Union players.

    Science.gov (United States)

    Russell, Mark; West, Daniel J; Briggs, Marc A; Bracken, Richard M; Cook, Christian J; Giroud, Thibault; Gill, Nicholas; Kilduff, Liam P

    2015-01-01

    Reduced physical performance has been observed following the half-time period in team sports players, likely due to a decrease in muscle temperature during this period. We examined the effects of a passive heat maintenance strategy employed between successive exercise bouts on core temperature (Tcore) and subsequent exercise performance. Eighteen professional Rugby Union players completed this randomised and counter-balanced study. After a standardised warm-up (WU) and 15 min of rest, players completed a repeated sprint test (RSSA 1) and countermovement jumps (CMJ). Thereafter, in normal training attire (Control) or a survival jacket (Passive), players rested for a further 15 min (simulating a typical half-time) before performing a second RSSA (RSSA 2) and CMJ's. Measurements of Tcore were taken at baseline, post-WU, pre-RSSA 1, post-RSSA 1 and pre-RSSA 2. Peak power output (PPO) and repeated sprint ability was assessed before and after the simulated half-time. Similar Tcore responses were observed between conditions at baseline (Control: 37.06±0.05°C; Passive: 37.03±0.05°C) and for all other Tcore measurements taken before half-time. After the simulated half-time, the decline in Tcore was lower (-0.74±0.08% vs. -1.54±0.06%, psprint times were 1.39±0.17% (prepeated sprint ability in professional Rugby Union players.

  8. Influence of the number of trials and the exercise to rest ratio in repeated sprint ability, with changes of direction and orientation.

    Science.gov (United States)

    Ruscello, Bruno; Tozzo, Nazzareno; Briotti, Gianluca; Padua, Elvira; Ponzetti, Francesco; D'Ottavio, Stefano

    2013-07-01

    The purpose of this investigation was to determine if there were different trends in physical fatigue observed in 3 different sets, of 7 trials each, in repeated sprint training, performed in 3 different modes: straight sprinting over 30 m, shuttle sprinting over 15 + 15 m, and sprinting over 30 m with changes of direction. Recovery time among trials in the sets was administered according to the 1:5 exercise to rest ratio. The sets were performed on 3 different days, with at least 48 hours between each set. The study involved 17 trained male soccer players (height, 177.33 ± 6.21 cm; body mass, 71.63 ± 9.58 kg; body mass index, 23 ± 2.39 kg·m; age, 21.94 ± 3.58 years). To compare the different values of the time recorded, an index of fatigue was used. Significant differences among trials within each set (repeated measures analysis of variance; p repeated sprint ability in nonlinear and multidirectional sprints (shuttle and change of direction), which might imply a different number of trials within the set or different exercise to rest ratios from the ones usually adopted for straight sprinting, to induce similar trends of fatigue. As practical applications, the estimated numbers of necessary trials in the different sets and the possible exercise to rest ratios, resulting from mathematical modeling, are provided for each investigated sprinting mode.

  9. Influence of training intensity on adaptations in acid/base transport proteins, muscle buffer capacity, and repeated-sprint ability in active men.

    Science.gov (United States)

    McGinley, Cian; Bishop, David J

    2016-12-01

    McGinley C, Bishop DJ. Influence of training intensity on adaptations in acid/base transport proteins, muscle buffer capacity, and repeated-sprint ability in active men. J Appl Physiol 121: 1290-1305, 2016. First published October 14, 2016; doi:10.1152/japplphysiol.00630.2016-This study measured the adaptive response to exercise training for each of the acid-base transport protein families, including providing isoform-specific evidence for the monocarboxylate transporter (MCT)1/4 chaperone protein basigin and for the electrogenic sodium-bicarbonate cotransporter (NBCe)1. We investigated whether 4 wk of work-matched, high-intensity interval training (HIIT), performed either just above the lactate threshold (HIITΔ20; n = 8), or close to peak aerobic power (HIITΔ90; n = 8), influenced adaptations in acid-base transport protein abundance, nonbicarbonate muscle buffer capacity (βmin vitro), and exercise capacity in active men. Training intensity did not discriminate between adaptations for most proteins measured, with abundance of MCT1, sodium/hydrogen exchanger (NHE) 1, NBCe1, carbonic anhydrase (CA) II, and CAXIV increasing after 4 wk, whereas there was little change in CAIII and CAIV abundance. βmin vitro also did not change. However, MCT4 protein content only increased for HIITΔ20 [effect size (ES): 1.06, 90% confidence limits × / ÷ 0.77], whereas basigin protein content only increased for HIITΔ90 (ES: 1.49, × / ÷ 1.42). Repeated-sprint ability (5 × 6-s sprints; 24 s passive rest) improved similarly for both groups. Power at the lactate threshold only improved for HIITΔ20 (ES: 0.49; 90% confidence limits ± 0.38), whereas peak O2 uptake did not change for either group. Detraining was characterized by the loss of adaptations for all of the proteins measured and for repeated-sprint ability 6 wk after removing the stimulus of HIIT. In conclusion, 4 wk of HIIT induced improvements in each of the acid-base transport protein families, but, remarkably, a 40

  10. Carbohydrate mouth rinse does not improve repeated sprint performance

    Directory of Open Access Journals (Sweden)

    Leandro Ricardo Altimari

    2013-09-01

    Full Text Available The objective of this study was to evaluate the effect of a carbohydrate mouth rinse on the repeated sprint ability (RSA of young soccer players. Nine youth soccer players (15.0 ± 1.5 years; 60.7 ± 4.84 kg; 1.72 ± 0.05 m; 20.5 ± 1.25 kg/m2 were selected. The athletes were submitted to an RSA test consisting of six sprints of 40 m (going/return = 20 m + 20 m, separated by 20 s of passive recovery, under three experimental conditions: carbohydrate mouth rinse (CHO or placebo (PLA and control (CON. The mouth rinses containing CHO or PLA were administered 5 min and immediately before the beginning of the test in doses of 100 mL. The best sprint time (RSAbest, mean sprint time (RSAmean, and drop-off in sprint performance (fatigue index were determined for the different treatments. One-not identify significant differences (p> 0.05 in RSAbest (CHO way ANOVA for repeated measures did = 7.30 ± 0.31 s; PLA = 7.30 ± 0.30 s; CON = 7.26 ±0.16 s, RSA mean (CHO = 7.71 ± 0.30 s; PLA = 7.71 ± 0.25 s; CON = 7.66 ± 0.24s, or fatigue index (CHO = 5.58 ± 2.16%; PLA = 5.77 ± 3.04%; CON = 5.55 ±3.72%. The results suggest that a carbohydrate mouth rinse does not improve the repeated sprint performance of young soccer players.

  11. A passive heat maintenance strategy implemented during a simulated half-time improves lower body power output and repeated sprint ability in professional Rugby Union players.

    Directory of Open Access Journals (Sweden)

    Mark Russell

    Full Text Available Reduced physical performance has been observed following the half-time period in team sports players, likely due to a decrease in muscle temperature during this period. We examined the effects of a passive heat maintenance strategy employed between successive exercise bouts on core temperature (Tcore and subsequent exercise performance. Eighteen professional Rugby Union players completed this randomised and counter-balanced study. After a standardised warm-up (WU and 15 min of rest, players completed a repeated sprint test (RSSA 1 and countermovement jumps (CMJ. Thereafter, in normal training attire (Control or a survival jacket (Passive, players rested for a further 15 min (simulating a typical half-time before performing a second RSSA (RSSA 2 and CMJ's. Measurements of Tcore were taken at baseline, post-WU, pre-RSSA 1, post-RSSA 1 and pre-RSSA 2. Peak power output (PPO and repeated sprint ability was assessed before and after the simulated half-time. Similar Tcore responses were observed between conditions at baseline (Control: 37.06±0.05°C; Passive: 37.03±0.05°C and for all other Tcore measurements taken before half-time. After the simulated half-time, the decline in Tcore was lower (-0.74±0.08% vs. -1.54±0.06%, p<0.001 and PPO was higher (5610±105 W vs. 5440±105 W, p<0.001 in the Passive versus Control condition. The decline in PPO over half-time was related to the decline in Tcore (r = 0.632, p = 0.005. In RSSA 2, best, mean and total sprint times were 1.39±0.17% (p<0.001, 0.55±0.06% (p<0.001 and 0.55±0.06% (p<0.001 faster for Passive versus Control. Passive heat maintenance reduced declines in Tcore that were observed during a simulated half-time period and improved subsequent PPO and repeated sprint ability in professional Rugby Union players.

  12. Repeated-sprint performance, locomotor profile and muscle oxygen uptake recovery: effect of training background.

    Science.gov (United States)

    Ufland, P; Ahmaidi, S; Buchheit, M

    2013-10-01

    The aim of the present study was to examine the respective importance of locomotor profile and muscle oxygen uptake (mV(˙)O₂) recovery on repeated-sprint ability (RSA) and overall repeated-sprint performance. 11 sprint- (STR) and 10 middle-distance-trained (MDTR) athletes (20.8±4.0 yr) performed an incremental test and a 40-to-50-m sprint to estimate their maximal aerobic (MAS) and sprinting (MSS) speeds. They also performed 6×30-m sprints, departing every 30 s, where mean (RS(mean)) sprint time was calculated. Muscle oxygenation (Near-infrared spectroscopy, NIRS, [Hb(diff)]) was measured for ~ 4 min post test. The mean response time of [Hb(diff)]-mV(˙)O₂ recovery (monoexponential curve fitting, MRT[Hb(diff)]-mV(˙)O₂) was calculated. Compared with MDTR, STR presented faster MSS (+11.4±6.7%, with 99% chances to observe a substantially greater value) and RS(mean) (-3.7±5.4%, 78%), but slower MAS (-15.8±8.0%, 100%) and MRT[Hb(diff)]-mV(˙)O₂ (+46.2±31.7%, 96%). RS(mean) was largely correlated with MSS [r=-0.83 (90%CL, -0.92;-0.67)], but neither with MAS [r=-0.12 (-0.47;0.25)] nor MRT[Hb(diff)]-mV(˙)O₂ [r=-0.27(-0.58;0.11)]. RS(mean) adjusted for MSS (which indirectly reflects RSA) was largely correlated with both MAS [r=0.51(0.18;0.74)] and MRT[Hb(diff)]-mV(˙)O₂ [r=0.53(0.20;0.75)]. While a fast mV(˙)O₂ recovery is associated with an improved RSA, MSS remains of primary importance for overall repeated-sprint performance (i.e., RS(mean)).

  13. Sport-Specific Repeated Sprint Training Improves Punching Ability And Upper-Body Aerobic Power In Experienced Amateur Boxers.

    Science.gov (United States)

    Kamandulis, Sigitas; Bruzas, Vidas; Mockus, Pranas; Stasiulis, Alvydas; Snieckus, Audrius; Venckunas, Tomas

    2017-08-09

    High-intensity interval training improves endurance and performance, but it is unclear whether sprint-type upper-body interval training is similarly effective. This study explored the effects of 4-week sport-specific sprint interval training on punch characteristics and endurance capacity in boxers. Experienced male amateur boxers (n = 18) participated in this 4-week training study, and were divided into an experimental group (EG) and a control group (CG) (n = 9 per group). Both groups completed standard low-intensity training. The EG also completed 3 rounds (14 sets of 3 s all-out punching with 10 s rest) of a simulated fight using a punching bag with 1 min rest between rounds 3 times per week, while the CG performed the same 3 rounds of a simulated fight at low intensity. Three rounds of 14 sets of 3 s all-out punching of a bag ergometer with 10 s rest were performed to measure punching abilities. Peak oxygen consumption and peak power were measured during progressive arm cranking before and after training. In response to training peak oxygen consumption and peak power in arm cranking test increased in EG; also, punching force increased and maintenance of punching frequency and punch force improved during the simulated fight, which resulted in greater cumulative force throughout the 3 rounds. There were no changes in the CG. The study shows that 1 month of all-out punching training (3 sessions per week with ∼2 min of all-out punching per session) improved both upper-body aerobic power and punching abilities in experienced amateur boxers.

  14. High-intensity interval training vs. repeated-sprint training in tennis.

    Science.gov (United States)

    Fernandez-Fernandez, Jaime; Zimek, Rico; Wiewelhove, Thimo; Ferrauti, Alexander

    2012-01-01

    The aim of this study was to compare the effects of high-intensity interval training (HIIT) and repeated-sprint training (RST) on aerobic fitness, tennis-specific endurance, linear and repeated-sprint ability (RSA), and jumping ability. Thirty-one competitive male tennis players took part in a training intervention of 6 weeks. The players were matched into 3 groups, HIIT (n = 11), RST (n = 12), or control group (CON, n = 9). The results showed significant time × intervention interactions for VO(2)peak, with a significant increase in the VO(2)peak level of 6.0% in HIIT (p = 0.008) and 4.9% in RST (p = 0.010), whereas no changes occurred in CON. However, the following differences were found between the intervention groups: The HIIT-induced greater improvements in tennis-specific endurance (HIIT 28.9% vs. RST 14.5%; p training strategy induced any effects on jumping and sprinting abilities. Both training interventions showed similar improvements in general aerobic fitness. Also, the present results suggest that RST represents a time-efficient stimulus for a simultaneous improvement of general and tennis-specific aerobic fitness as well for RSA.

  15. Comparison between traditional strength training and complex contrast training on repeated sprint ability and muscle architecture in elite soccer players.

    Science.gov (United States)

    Spineti, Juliano; Figueiredo, Tiago; Bastos DE Oliveira, Viviane; Assis, Marcio; Fernandes DE Oliveira, Liliam; Miranda, Humberto; Machado DE Ribeiro Reis, Victor M; Simão, Roberto

    2016-11-01

    The purpose of this study was to compare traditional strength training (TST) and complex contrast training (CCT) on the repeated-shuttle-sprint ability (RSSA), the countermovement squat jump (CMJ) height, the one repetition maximum (1RM) at squat on the Smith machine, and on muscle architecture in young, male elite soccer players. Twenty-two soccer players (mean age 18.4±0.4 years; mean weight 70.2±9.1 kg; mean height 179.9±7.5 cm) who belonged to the under-20 age group were randomly assigned into two groups: CCT (N.=10) or TST (N.=12). During the study period, the soccer players trained with CCT through power exercises performed before high-velocity exercises and TST based on a set-repetition format through daily, undulatory periodization. After statistical analysis (Pability (large effect size). However, the TST promoted significant changes in 1RM (large effect size) and a significant increase in the muscle thickness of the vastus intermedius (moderate effect size). The CCT protocol could be used to improve the RSSA parameters, CMJ and 1RM, and the TST developed dynamic strength and muscle growth. Coaches can choose either CCT or TST protocols according to the needs of their soccer players.

  16. Not quite so fast: effect of training at 90% sprint speed on maximal and repeated-sprint ability in soccer players.

    Science.gov (United States)

    Haugen, Thomas; Tonnessen, Espen; Leirstein, Svein; Hem, Erlend; Seiler, Stephen

    2014-12-01

    Abstract The aim of the present study was to investigate the effect of training at an intensity eliciting 90% of maximal sprinting speed on maximal and repeated-sprint performance in soccer. It was hypothesised that sprint training at 90% of maximal velocity would improve soccer-related sprinting. Twenty-two junior club-level male and female soccer players (age 17 ± 1 year, body mass 64 ± 8 kg, body height 174 ± 8 cm) completed an intervention study where the training group (TG) replaced one of their weekly soccer training sessions with a repeated-sprint training session performed at 90% of maximal sprint speed, while the control group (CG) completed regular soccer training according to their teams' original training plans. Countermovement jump, 12 × 20-m repeated-sprint, VO2max and the Yo-Yo Intermittent Recovery Level 1 test were performed prior to and after a 9-week intervention period. No significant between-group differences were observed for any of the performance indices and effect magnitudes were trivial or small. Before rejecting the hypothesis, we recommend that future studies should perform intervention programmes with either stronger stimulus or at other times during the season where total training load is reduced.

  17. Oxygen uptake during repeated-sprint exercise.

    Science.gov (United States)

    McGawley, Kerry; Bishop, David J

    2015-03-01

    Repeated-sprint ability appears to be influenced by oxidative metabolism, with reductions in fatigue and improved sprint times related to markers of aerobic fitness. The aim of the current study was to measure the oxygen uptake (VO₂) during the first and last sprints during two, 5 × 6-s repeated-sprint bouts. Cross-sectional study. Eight female soccer players performed two, consecutive, 5 × 6-s maximal sprint bouts (B1 and B2) on five separate occasions, in order to identify the minimum time (trec) required to recover total work done (Wtot) in B1. On a sixth occasion, expired air was collected during the first and last sprint of B1 and B2, which were separated by trec. The trec was 10.9 ± 1.1 min. The VO₂ during the first sprint was significantly less than the last sprint in each bout (psprint (measured in kJ) was significantly related to VO₂max in both B1 (r=0.81, p=0.015) and B2 (r=0.93, p=0.001). In addition, the VO₂ attained in the final sprint was not significantly different from VO₂max in B1 (p=0.284) or B2 (p=0.448). The current study shows that the VO₂ increases from the first to the last of 5 × 6-s sprints and that VO₂max may be a limiting factor to performance in latter sprints. Increasing V˙O₂max in team-sport athletes may enable increased aerobic energy delivery, and consequently work done, during a bout of repeated sprints. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  18. Hypoxic Repeat Sprint Training Improves Rugby Player's Repeated Sprint but Not Endurance Performance.

    Science.gov (United States)

    Hamlin, Michael J; Olsen, Peter D; Marshall, Helen C; Lizamore, Catherine A; Elliot, Catherine A

    2017-01-01

    hypoxia for six sessions increases repeat sprint ability but not YYIR1 performance in well-trained rugby players.

  19. Hypoxic Repeat Sprint Training Improves Rugby Player's Repeated Sprint but Not Endurance Performance

    Science.gov (United States)

    Hamlin, Michael J.; Olsen, Peter D.; Marshall, Helen C.; Lizamore, Catherine A.; Elliot, Catherine A.

    2017-01-01

    group. Repeat-sprint training in hypoxia for six sessions increases repeat sprint ability but not YYIR1 performance in well-trained rugby players. PMID:28223938

  20. Effects of four weeks of repeated sprint training on physiological indices in futsal players

    Directory of Open Access Journals (Sweden)

    Paulo Cesar do Nascimento

    2014-12-01

    Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2015v17n1p91   The aim of this study was to investigate the effects of short repeated-sprint ability (RSA training on the neuromuscular and physiological indices in U17 futsal players during the competitive period. Fourteen players were divided into two groups: intervention group (n = 8 and control group (n = 6. Both groups performed a repeated maximal sprint test (40-m MST, intermittent shuttle-running test (Carminatti’s test and vertical jumps before and after the training period. The intervention group was submitted to an additional four-week repeated sprints program, twice a week, while the control group maintained their normal training routine. There was no significant interaction between time and groups for all variables analysed (p > 0.05. However, a significant main effect was observed for time (p < 0.01 indicating an increase on speed at heart rate deflection point (VHRDP and the continuous jump performance while the peak lactate (40m-LACpeak and sprint decrement decreased after training, in both groups. Still, based on effect sizes (ES the greater changes with practical relevance were verified for intervention group in important variables such as peak velocity (ES = 0,71, VHRDP (ES = 0,83 and 40m-LACpeak (ES = 1,00. This study showed that RSA-based and normal training routine are equally effective in producing changes in the analysed variables during a short period of intervention. However, the effect size suggests that four weeks of RSA training would be a minimum time that could induce the first changes of futsal player’s physical fitness.

  1. Comparison of the effect of repeated-sprint training combined with two different methods of strength training on young soccer players.

    Science.gov (United States)

    Campos-Vazquez, Miguel A; Romero-Boza, Sergio; Toscano-Bendala, Francisco J; Leon-Prados, Juan A; Suarez-Arrones, Luis J; Gonzalez-Jurado, Jose A

    2015-03-01

    The aim of this study was to assess the effect of combining repeated-sprint training with 2 different methods of muscle strength training on physical performance variables in young players. Twenty-one soccer players with mean (± SD) age of 18.1 (± 0.8) years, weight 69.9 (± 6.5) kg, and height 177.1 (± 5.7) cm, and competing in U-19 category, were randomly assigned to 2 experimental groups: squat group (SG: n = 10) and take-off group (TG: n = 11). Intervention in both groups consisted of the combination of a weekly session of repeated-sprint training (the same for both groups), with 2 weekly sessions of strength training (different for each group), for 8 weeks in the final period of the season. The strength sessions for the SG consisted of conducting a series of full squats executed at maximum velocity in the concentric phase. Intervention in the TG was the performance of 2 specific strength exercises (take-offs and change of direction), with measurements taken before and after consideration of the following variables: repeated-sprint ability (RSA), yo-yo intermittent recovery test level 1 (YYIRT1), countermovement jump (CMJ), and average velocity in full squat progressive loads test. The SG improved CMJ height in 5.28% (p ≤ 0.05) and FS37.5-47.5-67.5 (p ≤ 0.05), whereas the TG improved FS17.5-27.5-37.5-47.5-67.5 (p ≤ 0.05). There were no significant changes in the values of RSA or YYIRT1 in either group. The results seem to show that the combination of a weekly session of repeated-sprint training with 2 weekly sessions of strength training could be an insufficient stimulus to improve RSA in the final period of the season.

  2. Repeated sprint performance and metabolic recovery curves: effects of aerobic and anaerobic characteristics.

    Science.gov (United States)

    de Aguiar, Rafael Alves; Turnes, Tiago; Santos de Oliveira Cruz, Rogério; Salvador, Amadeo Félix; Caputo, Fabrizio

    2015-05-01

    To examine the influence of aerobic and anaerobic indices on repeated sprint (RS) performance and ability (RSA), 8 sprinters (SPR), 8 endurance runners (END), and 8 active participants (ACT) performed the following tests: (i) incremental test; (ii) 1-min test to determine first decay time constant of pulmonary oxygen uptake off-kinetics and parameters related to anaerobic energy supply, lactate exchange, and removal abilities from blood lactate kinetics; and (iii) RS test (ten 35-m sprints, departing every 20 s) to determine best (RSbest) and mean (RSmean) sprint times and percentage of sprint decrement (%Dec). While SPR had a 98%-100% likelihood of having the fastest RSbest (Cohen's d of 1.8 and 1.4 for ACT and END, respectively) and RSmean (2.1 and 0.9 for ACT and END, respectively), END presented a 97%-100% likelihood of having the lowest %Dec (0.9 and 2.2 for ACT and SPR, respectively). RSmean was very largely correlated with RSbest (r=0.85) and moderately correlated with estimates of anaerobic energy supply (r=-0.40 to -0.49). RSmean adjusted for RSbest (which indirectly reflects RSA) was largely correlated with lactate exchange ability (r=0.55). Our results confirm the importance of locomotor- and anaerobic-related variables to RS performance, and highlight the importance of disposal of selected metabolic by-products to RSA.

  3. Relationship Between Repeated Sprint Performance and both Aerobic and Anaerobic Fitness.

    Science.gov (United States)

    Dardouri, Wajdi; Selmi, Mohamed Amin; Sassi, Radhouane Haj; Gharbi, Zied; Rebhi, Ahmed; Yahmed, Mohamed Haj; Moalla, Wassim

    2014-03-27

    The aims of this study were firstly, to examine the relationship between repeated sprint performance indices and anaerobic speed reserve (AnSR), aerobic fitness and anaerobic power and secondly, to identify the best predictors of sprinting ability among these parameters. Twenty nine subjects (age: 22.5 ± 1.6 years, body height: 1.8 ± 0.1 m, body mass: 68.8 ± 8.5 kg, body mass index (BMI): 22.2 ± 2.1 kg•m-2, fat mass: 11.3 ± 2.9 %) participated in this study. All participants performed a 30 m sprint test (T30) from which we calculated the maximal anaerobic speed (MAnS), vertical and horizontal jumps, 20m multi-stage shuttle run test (MSRT) and repeated sprint test (10 × 15 m shuttle run). AnSR was calculated as the difference between MAnS and the maximal speed reached in the MSRT. Blood lactate sampling was performed 3 min after the RSA protocol. There was no significant correlation between repeated sprint indices (total time (TT); peak time (PT), fatigue index (FI)) and both estimated VO2max and vertical jump performance). TT and PT were significantly correlated with T30 (r=0.63, p=0.001 and r=0.62, p=0.001; respectively), horizontal jump performance (r = -0.47, p = 0.001 and r = -0.49, p = 0.006; respectively) and AnSR (r=-0.68, p= 0.001 and r=-0.70, p=0.001, respectively). Significant correlations were found between blood lactate concentration and TT, PT, and AnSR (r=-0.44, p=0.017; r=-0.43, p=0.018 and r=0.44, p=0.016; respectively). Stepwise multiple regression analyses demonstrated that AnSR was the only significant predictor of the TT and PT, explaining 47% and 50% of the shared variance, respectively. Our findings are of particular interest for coaches and fitness trainers in order to predict repeated sprint performance by using AnSR that can easily identify the respective upper performance limits supported by aerobic and anaerobic power of a player involved in multi-sprint team sports.

  4. Relationship Between Repeated Sprint Performance and both Aerobic and Anaerobic Fitness

    Science.gov (United States)

    Dardouri, Wajdi; Selmi, Mohamed Amin; Sassi, Radhouane Haj; Gharbi, Zied; Rebhi, Ahmed; Yahmed, Mohamed Haj; Moalla, Wassim

    2014-01-01

    The aims of this study were firstly, to examine the relationship between repeated sprint performance indices and anaerobic speed reserve (AnSR), aerobic fitness and anaerobic power and secondly, to identify the best predictors of sprinting ability among these parameters. Twenty nine subjects (age: 22.5 ± 1.6 years, body height: 1.8 ± 0.1 m, body mass: 68.8 ± 8.5 kg, body mass index (BMI): 22.2 ± 2.1 kg•m-2, fat mass: 11.3 ± 2.9 %) participated in this study. All participants performed a 30 m sprint test (T30) from which we calculated the maximal anaerobic speed (MAnS), vertical and horizontal jumps, 20m multi-stage shuttle run test (MSRT) and repeated sprint test (10 × 15 m shuttle run). AnSR was calculated as the difference between MAnS and the maximal speed reached in the MSRT. Blood lactate sampling was performed 3 min after the RSA protocol. There was no significant correlation between repeated sprint indices (total time (TT); peak time (PT), fatigue index (FI)) and both estimated VO2max and vertical jump performance). TT and PT were significantly correlated with T30 (r=0.63, p=0.001 and r=0.62, p=0.001; respectively), horizontal jump performance (r = −0.47, p = 0.001 and r = −0.49, p = 0.006; respectively) and AnSR (r=−0.68, p= 0.001 and r=−0.70, p=0.001, respectively). Significant correlations were found between blood lactate concentration and TT, PT, and AnSR (r=−0.44, p=0.017; r=−0.43, p=0.018 and r=0.44, p=0.016; respectively). Stepwise multiple regression analyses demonstrated that AnSR was the only significant predictor of the TT and PT, explaining 47% and 50% of the shared variance, respectively. Our findings are of particular interest for coaches and fitness trainers in order to predict repeated sprint performance by using AnSR that can easily identify the respective upper performance limits supported by aerobic and anaerobic power of a player involved in multi-sprint team sports. PMID:25031682

  5. SHORT DURATIONS OF STATIC STRETCHING WHEN COMBINED WITH DYNAMIC STRETCHING DO NOT IMPAIR REPEATED SPRINTS AND AGILITY

    Directory of Open Access Journals (Sweden)

    Del P. Wong

    2011-06-01

    Full Text Available This study aimed to compare the effect of different static stretching durations followed by dynamic stretching on repeated sprint ability (RSA and change of direction (COD. Twenty-five participants performed the RSA and COD tests in a randomized order. After a 5 min aerobic warm up, participants performed one of the three static stretching protocols of 30 s, 60 s or 90 s total duration (3 stretches x 10 s, 20 s or 30 s. Three dynamic stretching exercises of 30 s duration were then performed (90 s total. Sit-and-reach flexibility tests were conducted before the aerobic warm up, after the combined static and dynamic stretching, and post- RSA/COD test. The duration of static stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit-and-reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p < 0.001. However there were no significant differences in RSA and COD performance between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. Furthermore, the short duration (< 90 s static stretching may not have provided sufficient stimulus to elicit performance impairments

  6. The effect of combined resisted agility and repeated sprint training vs. strength training on female elite soccer players.

    Science.gov (United States)

    Shalfawi, Shaher A I; Haugen, Thomas; Jakobsen, Tore A; Enoksen, Eystein; Tønnessen, Espen

    2013-11-01

    The aim of this study was to compare the effects of in-season combined resisted agility and repeated sprint training with strength training on soccer players' agility, linear single sprint speed, vertical jump, repeated sprint ability (RSA), and aerobic capacity. Twenty well-trained elite female soccer players of age ± SD 19.4 ± 4.4 years volunteered to participate in this study. The participants were randomly assigned to either the agility and repeated sprint training group or to the strength training group. All the participants were tested before and after a 10-week specific conditioning program. The pretest and posttest were conducted on 3 separate days with 1 day of low-intensity training in between. Test day 1 consisted of squat jump (SJ), countermovement jump (CMJ), and RSA. Test day 2 consisted of a 40-m maximal linear sprint and an agility test, whereas a Beep test was conducted on test day 3 to assess aerobic capacity. The agility and repeated sprint training implemented in this study did not have a significant effect on agility, although there was a tendency for moderate improvements from 8.23 ± 0.32 to 8.06 ± 0.21 seconds (d = 0.8). There was a significant (p < 0.01) and moderate-positive effect on Beep-test performance from level 9.6 ± 1.4 to level 10.8 ± 1.0, and only a trivial small effect on all other physical variables measured in this study. The strength training group had a positive, moderate, and significant (p < 0.01) effect on Beep-test performance from level 9.7 ± 1.3 to level 10.9 ± 1.2 (d = 1.0) and a significant (p < 0.05) but small effect (d = 0.5) on SJ performance (25.9 ± 2.7 to 27.5 ± 4.1 cm). Furthermore, the strength training implemented in this study had a trivial and negative effect on agility performance (d = -0.1). No between-group differences were observed. The outcome of this study indicates the importance of a well-planned program of conditioning that does not result in a decreased performance of the players, the

  7. Research Advancement of Metabolic Mechanisms about Repeated Sprint Ability for Team Ball Games Players%集体球类项目运动员反复冲刺能力的能量代谢机制的研究现状

    Institute of Scientific and Technical Information of China (English)

    刘小平; 程丽平

    2012-01-01

    对于集体球类项目(篮球、足球、橄榄球、手球等)来讲,运动员为了有效地完成比赛的技战术要求,取得竞争优势,必须在场上进行反复的高强度冲刺活动,所以反复冲刺的能力(Repeated-sprint ability:RSA)对运动员的竞技表现是至关重要的。本文旨在通过对国内外集体球类项目运动员反复冲刺能力的研究成果进行梳理分析,总结归纳出反复冲刺能力的能量代谢基础、测试方法及影响因素,以期能对我国竞技水平普遍不高的集体球类运动项目的科学化训练提供理论指导。%For the team ball games(basketball,football,rugby,etc.),the athlete must run high intensity sprint repeatedly in the field or court to effectively complete the game's technical and tactical requirements and get competitive advantage,therefore,repeated sprint ability(repeated-sprint ability: RSA) of the athletes is essential.This paper makes comprehensive review on research results about repeated sprint ability at home and abroad.The main purpose of this paper is to summarize physiological basis,test methods and impact factors of repeated sprint ability and provide theoretical guidance for team ball games scientific training.

  8. LONGITUDINAL STUDY OF REPEATED SPRINT PERFORMANCE IN YOUTH SOCCER PLAYERS OF CONTRASTING SKELETAL MATURITY STATUS

    Directory of Open Access Journals (Sweden)

    João Valente-dos-Santos

    2012-09-01

    Full Text Available The purpose of the study was to evaluate the developmental changes in performance in a repeated-sprint ability (RSA test in young soccer players of contrasting maturity status. A total of 83 regional level Portuguese youth soccer players, aged 11- 13 years at baseline was assessed annually. Stature, body mass, 7x34.2-m sprint protocol (25-s active recovery, 20-m multi-stage continuous shuttle endurance run and counter-movement jump (CMJ without the use of the arms were measured. Fat-free mass (FFM was determined by age and gender- specific formulas. Developmental changes in total sprint time across ages were predicted using multilevel modeling. Corresponding measurements were performed on an independent cross-sectional subsample of 52 youth soccer players 11-17 years to evaluate the predictive model. CA, CA2, maturational status (SA-CA, body size (mass and stature, FFM, aerobic endurance, lower limb explosive strength and annual volume training significantly improved the statistical fit of the RSA multilevel model. In 'late' maturing athletes, the best model for predicting change in RSA was expressed by the following equation: 86.54 - 2.87 x CA + 0.05 x CA2 - 0.25 x FFM + 0.15 x body mass + 0.05 x stature - 0.05 x aerobic endurance - 0.09 x lower limb explosive strength - 0.01 x annual volume training. The best fitting models for players who were 'on time' and 'early' maturing were identical to the best model for late maturing players, less 0.64 seconds and 1.74 seconds, respectively. Multilevel modeling provided performance curves that permitted the prediction of individual RSA performance across adolescent years in regional level soccer players

  9. Short Durations of Static Stretching when Combined with Dynamic Stretching do not Impair Repeated Sprints and Agility

    Science.gov (United States)

    Wong, Del P.; Chaouachi, Anis; Lau, Patrick W.C.; Behm, David G.

    2011-01-01

    This study aimed to compare the effect of different static stretching durations followed by dynamic stretching on repeated sprint ability (RSA) and change of direction (COD). Twenty-five participants performed the RSA and COD tests in a randomized order. After a 5 min aerobic warm up, participants performed one of the three static stretching protocols of 30 s, 60 s or 90 s total duration (3 stretches x 10 s, 20 s or 30 s). Three dynamic stretching exercises of 30 s duration were then performed (90 s total). Sit-and-reach flexibility tests were conducted before the aerobic warm up, after the combined static and dynamic stretching, and post- RSA/COD test. The duration of static stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit-and-reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p ≤ 0.001). However there were no significant differences in RSA and COD performance between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. Furthermore, the short duration (≤ 90 s) static stretching may not have provided sufficient stimulus to elicit performance impairments. Key points The duration of combined static and dynamic stretching had a positive effect on flexibility with 36.3% and 85.6% greater sit and reach scores with the 60 s and 90 s static stretching conditions respectively than with the 30 s condition (p ≤ 0.001). No significant differences in RSA and COD between the 3 stretching conditions. The lack of change in RSA and COD might be attributed to a counterbalancing of static and dynamic stretching effects. The short duration (≤ 90 s) static stretching may not have provided sufficient stimulus to elicit performance impairments. PMID:24149890

  10. In-season effect of a combined repeated sprint and explosive strength training program on elite junior tennis players.

    Science.gov (United States)

    Fernandez-Fernandez, Jaime; Sanz-Rivas, David; Kovacs, Mark S; Moya, Manuel

    2015-02-01

    The aim of this study was to analyze the effects of a combined explosive strength (ExpS) and repeated sprint (RS)-training program (2 times per week) on performance (sprint, jumping ability, and RS ability [RSA]) in young elite tennis players during a competitive period. Eight competitive internationally ranked male junior tennis players participated in an 8-week training intervention. After training, except for percentage of decrement in the RS test (p = 0.72) and maximal aerobic performance (p = 1.0), all performance variables (i.e., sprint, countermovement jump, and RSA) were significantly improved (p ≤ 0.05; effect sizes ranging from 0.56 to 1.12). Although one can expect greater effects of ExpS or RS training programs alone than a combined program, the results obtained here show that the inclusion of a combined ExpS and RS training program seems to be an effective training tool to improve neuromuscular performance (i.e., changes in jumping ability and single sprint) as well as RSA in high-level tennis players.

  11. Diurnal variations of plasma homocysteine, total antioxidant status, and biological markers of muscle injury during repeated sprint: effect on performance and muscle fatigue--a pilot study.

    Science.gov (United States)

    Hammouda, Omar; Chtourou, Hamdi; Chahed, Henda; Ferchichi, Salyma; Kallel, Choumous; Miled, Abdelhedi; Chamari, Karim; Souissi, Nizar

    2011-12-01

    The aim of this study was (i) to evaluate whether homocysteine (Hcy), total antioxidant status (TAS), and biological markers of muscle injury would be affected by time of day (TOD) in football players and (ii) to establish a relationship between diurnal variation of these biomarkers and the daytime rhythm of power and muscle fatigue during repeated sprint ability (RSA) exercise. In counterbalanced order, 12 football (soccer) players performed an RSA test (5 x[6 s of maximal cycling sprint + 24 s of rest]) on two different occasions: 07:00-08:30 h and 17:00-18:30 h. Fasting blood samples were collected from a forearm vein before and 3-5 min after each RSA test. Core temperature, rating of perceived exertion, and performances (i.e., Sprint 1, Sprint 2, and power decrease) during the RSA test were significantly higher at 17:00 than 07:00 h (p RSA test. However, biomarkers of antioxidant status' resting levels (i.e., total antioxidant status, uric acid, and total bilirubin) were higher in the morning. This TOD effect was suppressed after exercise for TAS and uric acid. In conclusion, the present study confirms diurnal variation of Hcy, selected biological markers of cellular damage, and antioxidant status in young football players. Also, the higher performances and muscle fatigue showed in the evening during RSA exercise might be due to higher levels of biological markers of muscle injury and lower antioxidant status at this TOD.

  12. Neck-cooling improves repeated sprint performance in the heat

    Directory of Open Access Journals (Sweden)

    Caroline eSunderland

    2015-11-01

    Full Text Available The present study evaluated the effect of neck-cooling during exercise on repeated sprint ability in a hot environment. Seven team-sport playing males completed two experimental trials involving repeated sprint exercise (5 x 6 s before and after two 45 min bouts of a football specific intermittent treadmill protocol in the heat (33.0  0.2 ºC; 53 ± 2% relative humidity. Participants wore a neck-cooling collar in one of the trials (CC. Mean power output and peak power output declined over time in both trials but were higher in CC (540 ± 99 v 507 ± 122W, d = 0.32; 719 ± 158 v 680 ± 182 W, d = 0.24 respectively. The improved power output was particularly pronounced (d = 0.51 – 0.88 after the 2nd 45 min bout but the CC had no effect on % fatigue. The collar lowered neck temperature and the thermal sensation of the neck (P 0.05. There were no trial differences but interaction effects were demonstrated for prolactin concentration and rating of perceived exertion (RPE. Prolactin concentration was initially higher in the collar cold trial and then was lower from 45 minutes onwards (interaction trial x time P=0.04. RPE was lower during the football intermittent treadmill protocol in the collar cold trial (interaction trial x time P = 0.01. Neck-cooling during exercise improves repeated sprint performance in a hot environment without altering physiological or neuroendocrinological responses. RPE is reduced and may partially explain the performance improvement.

  13. Use of the RSA/RCOD Index to Identify Training Priority in Soccer Players.

    Science.gov (United States)

    Wong, Del P; Hjelde, Geir H; Cheng, Ching-Feng; Ngo, Jake K

    2015-10-01

    The use of RSA/RCOD index indicates the repeated change-of-direction (RCOD) performance relative to the repeated-sprint ability (RSA) and provides a standardized approach to prioritize training needs for RSA and RCOD. To compare the RSA/RCOD index among different age groups, RSA and RCOD were measured from 20 under-16 players (U16), 20 under-19 players (U19), and 17 first-team professional players (PRO) from a football (soccer) club that has regular participation in the UEFA Champions League. Each player performed the RSA and RCOD tests, during which the fastest time (FT), average time (AT), total time (TT), and percentage decrement score (%Dec) were recorded. No significant differences were found in RSA/RCOD index-FT, AT, TT, and %Dec among the 3 groups (p > 0.05) and between U19 and PRO in all RSA and RCOD measures (p > 0.05). Most values of RSA/RCOD index were 0.51 among the U16, U19, and PRO groups. Moreover, we concluded that the RSA/RCOD index might not be further changed after 16 years of age unless specific training programs for RSA and RCOD are prescribed. Therefore, this study provides an empirical case, and coaches can establish the RSA/RCOD index value relevant to their training system and monitor players' training needs of RSA and RCOD in a longer term.

  14. Effect of training in hypoxia on repeated sprint performance in female athletes.

    Science.gov (United States)

    Kasai, Nobukazu; Mizuno, Sahiro; Ishimoto, Sayuri; Sakamoto, Etsuko; Maruta, Misato; Goto, Kazushige

    2015-01-01

    This study determined the effect of repeated sprint training in hypoxia (RSH) in female athletes. Thirty-two college female athletes performed repeated cycling sprints of two sets of 10 × 7-s sprints with a 30-s rest between sprints twice per week for 4 weeks under either normoxic conditions (RSN group; FiO2, 20.9%; n = 16) or hypoxic conditions (RSH group; FiO2, 14.5%; n = 16). The repeated sprint ability (10 × 7-s sprints) and maximal oxygen uptake ([Formula: see text]) were determined before and after the training period. After training, when compared to pre-values, the mean power output was higher in all sprints during the repeated sprint test in the RSH group but only for the second half of the sprints in the RSN group (P ≤ 0.05). The percentage increases in peak and mean power output between before and after the training period were significantly greater in the RSH group than in the RSN group (peak power output, 5.0 ± 0.7% vs. 1.5 ± 0.9%, respectively; mean power output, 9.7 ± 0.9% vs. 6.0 ± 0.8%, respectively; P repeated sprint test compared with RSN.

  15. Performance and physiological responses to repeated-sprint exercise: a novel multiple-set approach.

    Science.gov (United States)

    Serpiello, Fabio R; McKenna, Michael J; Stepto, Nigel K; Bishop, David J; Aughey, Robert J

    2011-04-01

    We investigated the acute and chronic responses to multiple sets of repeated-sprint exercise (RSE), focusing on changes in acceleration, intermittent running capacity and physiological responses. Ten healthy young adults (7 males, 3 females) performed an incremental test, a Yo-Yo intermittent recovery test level1 (Yo-Yo IR1), and one session of RSE. RSE comprised three sets of 5 × 4-s maximal sprints on a non-motorised treadmill, with 20 s of passive recovery between repetitions and 4.5 min of passive recovery between sets. After ten repeated-sprint training sessions, participants repeated all tests. During RSE, performance was determined by measuring acceleration, mean and peak power/velocity. Recovery heart rate (HR), HR variability, and finger-tip capillary lactate concentration ([Lac(-)]) were measured. Performance progressively decreased across the three sets of RSE, with the indices of repeated-sprint ability being impaired to a different extent before and after training. Training induced a significant increase (p RSE. There were strong correlations between Yo-Yo IR1 performance and indices of RSE performance, especially acceleration post-training (r = 0.88, p = 0.004). Repeated-sprint training, comprising only 10 min of exercise overall, effectively improved performance during multiple-set RSE. This exercise model better reflects team-sport activities than single-set RSE. The rapid training-induced improvement in acceleration, quantified here for the first time, has wide applications for professional and recreational sport activities.

  16. The effect of a short practical warm-up protocol on repeated sprint performance.

    Science.gov (United States)

    Taylor, Jonathan M; Weston, Matthew; Portas, Matthew D

    2013-07-01

    The aim of our study was to investigate the effect of a short, practical, 2-phase warm-up on repeated sprint performance when compared with more traditional warm-up protocols that contain stretching activities. Eleven subelite male soccer players completed a warm-up protocol that commenced with 5 minutes jogging at approximately 65% of maximal heart rate, followed by no stretching, static stretching, or dynamic stretching and finishing with a task-specific high-intensity activity. Using a crossover design, the 3 warm-up protocols were performed in a counterbalanced order with at least 48 hours between sessions. Repeated sprint performance was measured using a repeated sprint test that consisted of 6 × 40-m maximal sprints interspersed with a 20-second recovery. There were trivial differences in mean sprint time (0.2%) and posttest blood lactate (3.1%) between the 2-phase warm-up and the 3-phase warm-up that included dynamic stretching, whereas the short warm-up had a possibly detrimental effect on fastest sprint time (0.7%). Fastest (-1.1%) and mean (-1.2%) sprint times were quicker and posttest blood lactates were higher (13.2%) after the 2-phase warm-up when compared with the 3-phase warm-up that included static stretching. Although it is not harmful to complete a traditional 3-phase warm-up that includes dynamic stretching, it appears practical for athletes preparing for activities dependent on repeated sprint ability to complete a 2-phase warm-up consisting of a cardiovascular and specific high-intensity activity.

  17. Fatigue in repeated-sprint exercise is related to muscle power factors and reduced neuromuscular activity.

    Science.gov (United States)

    Mendez-Villanueva, Alberto; Hamer, Peter; Bishop, David

    2008-07-01

    The purpose of this study was (1) to determine the relationship between each individual's anaerobic power reserve (APR) [i.e., the difference between the maximum anaerobic (Pana) and aerobic power (Paer)] and fatigability during repeated-sprint exercise and (2) to examine the acute effects of repeated sprints on neuromuscular activity, as evidenced by changes in the surface electromyogram (EMG) signals. Eight healthy males carried out tests to determine Pana (defined as the highest power output attained during a 6-s cycling sprint), Paer (defined as the highest power output achieved during a progressive, discontinuous cycling test to failure) and a repeated cycling sprint test (10 x 6-s max sprints with 30 s rest). Peak power output (PPO) and mean power output (MPO) were calculated for each maximal 6-s cycling bout. Root mean square (RMS) was utilized to quantify EMG activity from the vastus lateralis (VL) muscle of the right leg. Over the ten sprints, PPO and MPO decreased by 24.6 and 28.3% from the maximal value (i.e., sprint 1), respectively. Fatigue index during repeated sprints was significantly correlated with APR (R = 0.87; P < 0.05). RMS values decreased over the ten sprints by 14.6% (+/-6.3%). There was a strong linear relationship (R2 = 0.97; P < 0.05) between the changes in MPO and EMG RMS from the vastus lateralis muscle during the ten sprints. The individual advantage in fatigue-resistance when performing a repeated sprint task was related with a lower anaerobic power reserve. Additionally, a suboptimal net motor unit activity might also impair the ability to repeatedly generate maximum power outputs.

  18. Efecto de un calentamiento con estiramientos estáticos y dinámicos sobre el salto horizontal y la capacidad para repetir esprint con cambio de dirección. [Effect of warm-up with static and dynamic stretching on the horizontal jump and repeated sprint ability with changes of direction].

    Directory of Open Access Journals (Sweden)

    Javier Sánchez-Sánchez

    2017-01-01

    Full Text Available El objetivo de este trabajo ha sido comparar el efecto de tres calentamientos diferentes (calentamiento aeróbico de baja intensidad, estiramiento estático y estiramiento dinámico sobre el salto horizontal y la capacidad de repetir esprint con cambios de dirección. Diecisiete practicantes de deportes de equipo de 20.8±1.1 años realizaron 3 tipos de calentamiento (10 min: ejercicio aeróbico sin estiramiento (CAE, con estiramiento estático (CAES y con estiramiento dinámico (CAED. Se estudió el efecto agudo de cada calentamiento sobre el rendimiento en una prueba de salto horizontal (SH y un test de repetición de esprint con cambio de dirección (RSCOD. No se obtuvieron diferencias significativas (p>0,05 en ninguna de las variables en función del calentamiento realizado. El tamaño del efecto (TE indicó que probablemente el RSCODmejor sea más sensible al CAE que al CAES (TE: 0,52 y al CAED (TE: 0,44. El escaso efecto de los estiramientos estáticos sobre el rendimiento en SH y RSCOD puede ser debido a la dosis, la intensidad y el tiempo de recuperación empleado. Los estiramientos dinámicos no mejoraron el rendimiento en SH y RSCOD. Abstract The purpose of this study was to compare the effect of three different warm-ups (low intensity aerobic warm-up, static stretching and dynamic stretching on the horizontal jump and repeated sprint ability with changes of direction. Seventeen players of team sports whose age was 20.8±1.1 years old performed three types of warm up (10 minutes: aerobic exercise without stretching (WU, with static stretching (WUSS and with dynamic stretching (WUDS. The acute effect of each warming over performance was studied in a test of horizontal jump (HJ and repeat sprint test with change of direction (RSCD. No significant differences were obtained (p>0.05 in any of the variables studied according to the warming developed. The effect size (ES indicated that probably RSCDbest was more sensitive to WU than WUDS (ES

  19. Repeated-Sprint Sequences During Female Soccer Matches Using Fixed and Individual Speed Thresholds.

    Science.gov (United States)

    Nakamura, Fábio Y; Pereira, Lucas A; Loturco, Irineu; Rosseti, Marcelo; Moura, Felipe A; Bradley, Paul S

    2017-07-01

    Nakamura, FY, Pereira, LA, Loturco, I, Rosseti, M, Moura, FA, and Bradley, PS. Repeated-sprint sequences during female soccer matches using fixed and individual speed thresholds. J Strength Cond Res 31(7): 1802-1810, 2017-The main objective of this study was to characterize the occurrence of single sprint and repeated-sprint sequences (RSS) during elite female soccer matches, using fixed (20 km·h) and individually based speed thresholds (>90% of the mean speed from a 20-m sprint test). Eleven elite female soccer players from the same team participated in the study. All players performed a 20-m linear sprint test, and were assessed in up to 10 official matches using Global Positioning System technology. Magnitude-based inferences were used to test for meaningful differences. Results revealed that irrespective of adopting fixed or individual speed thresholds, female players produced only a few RSS during matches (2.3 ± 2.4 sequences using the fixed threshold and 3.3 ± 3.0 sequences using the individually based threshold), with most sequences composing of just 2 sprints. Additionally, central defenders performed fewer sprints (10.2 ± 4.1) than other positions (fullbacks: 28.1 ± 5.5; midfielders: 21.9 ± 10.5; forwards: 31.9 ± 11.1; with the differences being likely to almost certainly associated with effect sizes ranging from 1.65 to 2.72), and sprinting ability declined in the second half. The data do not support the notion that RSS occurs frequently during soccer matches in female players, irrespective of using fixed or individual speed thresholds to define sprint occurrence. However, repeated-sprint ability development cannot be ruled out from soccer training programs because of its association with match-related performance.

  20. The effects of repeated-sprint training on field-based fitness measures: a meta-analysis of controlled and non-controlled trials.

    Science.gov (United States)

    Taylor, Jonathan; Macpherson, Tom; Spears, Iain; Weston, Matthew

    2015-06-01

    Repeated-sprint training appears to be an efficient and practical means for the simultaneous development of different components of fitness relevant to team sports. Our objective was to systematically review the literature and meta-analyse the effect of repeated-sprint training on a selection of field-based measures of athletic performance, i.e. counter-movement jump, 10 m sprint, 20 m sprint, 30 m sprint, repeated-sprint ability and high-intensity intermittent running performance. The SPORTDiscus, PubMed, MEDLINE and Web of Science databases were searched for original research articles. Search terms included 'repeated-sprint training', 'sprint training', 'aerobic endurance', 'repeated-sprint ability', 'counter-movement jump' and 'sprint performance'. Inclusion criteria included intervention consisting of a series of ≤10 s sprints with ≤60 s recovery; trained participants; intervention duration of 2-12 weeks; field-based fitness measures; running- or cycling-based intervention; published up to, and including, February 2014. Our final dataset included six trials for counter-movement jump (two controlled trials), eight trials for 10 m sprint, four trials for 20 m sprint (three controlled trials), two trials for 30 m sprint, eight trials for repeated-sprint ability and three trials for high-intensity intermittent running performance. Analyses were conducted using comprehensive meta-analysis software. Uncertainty in the meta-analysed effect of repeated-sprint training was expressed as 95% confidence limits (CL), along with the probability that the true value of the effect was trivial, beneficial or harmful. Magnitude-based inferences were based on standardised thresholds for small, moderate and large changes of 0.2, 0.6 and 1.2 standard deviations, respectively. Repeated-sprint training had a likely small beneficial effect in non-controlled counter-movement jump trials (effect size 0.33; 95% CL ±0.30), with a possibly moderate beneficial effect in controlled

  1. Higher Drop in Speed during a Repeated Sprint Test in Soccer Players Reporting Former Hamstring Strain Injury.

    Science.gov (United States)

    Røksund, Ola D; Kristoffersen, Morten; Bogen, Bård E; Wisnes, Alexander; Engeseth, Merete S; Nilsen, Ann-Kristin; Iversen, Vegard V; Mæland, Silje; Gundersen, Hilde

    2017-01-01

    strain injury. The maximal speed, leg strength, ability to produce maximal power, endurance capacity, and hamstring flexibility was similar for both groups. Thus, a repeated sprint test consisting of 8 × 20 m could be used as a field-based diagnostic tool to identify players in need of reconditioning programs to ensure complete post-injury rehabilitation.

  2. Higher Drop in Speed during a Repeated Sprint Test in Soccer Players Reporting Former Hamstring Strain Injury

    Science.gov (United States)

    Røksund, Ola D.; Kristoffersen, Morten; Bogen, Bård E.; Wisnes, Alexander; Engeseth, Merete S.; Nilsen, Ann-Kristin; Iversen, Vegard V.; Mæland, Silje; Gundersen, Hilde

    2017-01-01

    strain injury. The maximal speed, leg strength, ability to produce maximal power, endurance capacity, and hamstring flexibility was similar for both groups. Thus, a repeated sprint test consisting of 8 × 20 m could be used as a field-based diagnostic tool to identify players in need of reconditioning programs to ensure complete post-injury rehabilitation. PMID:28190999

  3. Performance and physiological responses to repeated-sprint and jump sequences.

    Science.gov (United States)

    Buchheit, Martin

    2010-11-01

    In this study, the performance and selected physiological responses to team-sport specific repeated-sprint and jump sequence were investigated. On four occasions, 13 team-sport players (22 ± 3 year) performed alternatively six repeated maximal straight-line or shuttle-sprints interspersed with a jump ([RS(+j), 6 × 25 m] or [RSS(+j), 6 × (2 × 12.5 m)]) or not ([RS, 6 × 25 m] or [RSS, 6 × (2 × 12.5 m)]) within each recovery period. Mean running time, rate of perceived exertion (RPE), pulmonary oxygen uptake (V(O)₂), blood lactate ([La](b)), and vastus lateralis deoxygenation ([HHb]) were obtained for each condition. Mean sprint times were greater for RS(+j) versus RS (4.14 ± 0.17 vs. 4.09 ± 0.16 s, with the qualitative analysis revealing a 82% chance of RS(+j) times to be greater than RS) and for RSS(+j) versus RSS (5.43 ± 0.18 vs. 5.29 ± 0.17 s; 99% chance of RSS(+j) to be >RSS). The correlation between sprint and jump abilities were large-to-very-large, but below 0.71 for RSSs. Jumps increased RPE (Cohen's d ± 90% CL: +0.7 ± 0.5; 95% chance for RS(+j) > RS and +0.7 ± 0.5; 96% for RSS(+j) > RSS), V(O)₂(+0.4 ± 0.5; 80% for RS(+j) > RS and +0.5 ± 0.5; 86% for RSS(+j) > RSS), [La](b) (+0.5 ± 0.5; 59% for RS(+j) > RS and +0.2 ± 0.5; unclear for RSS(+j) > RSS), and [HHb] (+0.5 ± 0.5; 86% for RS(+j) > RS and +0.5 ± 0.5; 85% for RSS(+j) > RSS). To conclude, repeated- sprint and jump abilities could be considered as specific qualities. The addition of a jump within the recovery periods during repeated-sprint running sequences impairs sprinting performance and might be an effective training practice for eliciting both greater systemic and vastus lateralis physiological loads.

  4. Elevations in core and muscle temperature impairs repeated sprint performance

    DEFF Research Database (Denmark)

    Drust, B.; Rasmussen, P.; Mohr, Magni

    2005-01-01

    following the hyperthermic sprints compared to control. CONCLUSION: Although an elevated muscle temperature is expected to promote sprint performance, power output during the repeated sprints was reduced by hyperthermia. The impaired performance does not seem to relate to the accumulation of recognized...... on a cycle ergometer in normal (approximately 20 degrees C, control) and hot (40 degrees C, hyperthermia) environments. RESULTS: Completion of the intermittent protocol in the heat elevated core and muscle temperatures (39.5 +/- 0.2 degrees C; 40.2 +/- 0.4 degrees C), heart rate (178 +/- 11 beats min(-1......)), rating of perceived exertion (RPE) (18 +/- 1) and noradrenaline (38.9 +/- 13.2 micromol l(-1)) (all P power output were similar across the environmental conditions. However, mean power over the last four sprints declined to a larger extent...

  5. The effect of 40-m repeated sprint training on maximum sprinting speed, repeated sprint speed endurance, vertical jump, and aerobic capacity in young elite male soccer players.

    Science.gov (United States)

    Tønnessen, Espen; Shalfawi, Shaher A I; Haugen, Thomas; Enoksen, Eystein

    2011-09-01

    The purpose of this study was to examine the effect of 10 weeks' 40-m repeated sprint training program that does not involve strength training on sprinting speed and repeated sprint speed on young elite soccer players. Twenty young well-trained elite male soccer players of age (±SD) 16.4 (±0.9) years, body mass 67.2 (±9.1) kg, and stature 176.3 (±7.4) cm volunteered to participate in this study. All participants were tested on 40-m running speed, 10 × 40-m repeated sprint speed, 20-m acceleration speed, 20-m top speed, countermovement jump (CMJ), and aerobic endurance (beep test). Participants were divided into training group (TG) (n = 10) and control group (CG) (n = 10). The study was conducted in the precompetition phase of the training program for the participants and ended 13 weeks before the start of the season; the duration of the precompetition period was 26 weeks. The TG followed a Periodized repeated sprint training program once a week. The training program consisted of running 40 m with different intensities and duration from week to week. Within-group results indicate that TG had a statistically marked improvement in their performance from pre to posttest in 40-m maximum sprint (-0.06 seconds), 10 × 40-m repeated sprint speed (-0.12 seconds), 20- to 40-m top speed (-0.05 seconds), and CMJ (2.7 cm). The CG showed only a statistically notable improvement from pre to posttest in 10 × 40-m repeated sprint speed (-0.06 seconds). Between-group differences showed a statistically marked improvement for the TG over the CG in 10 × 40-m repeated sprint speed (-0.07 seconds) and 20- to 40-m top speed (-0.05 seconds), but the effect of the improvement was moderate. The results further indicate that a weekly training with repeated sprint gave a moderate but not statistically marked improvement in 40-m sprinting, CMJ, and beep test. The results of this study indicate that the repeated sprint program had a positive effect on several of the parameters tested

  6. Effect of endurance training on performance and muscle reoxygenation rate during repeated-sprint running.

    Science.gov (United States)

    Buchheit, Martin; Ufland, Pierre

    2011-02-01

    The aim of the present study was to examine the effect of an 8-week endurance training program on repeated-sprint (RS) performance and post-sprints muscle reoxygenation rate in 18 moderately trained males (34 ± 5 years). Maximal aerobic speed (MAS), 10 km running and RS (2 × 15-s shuttle-sprints, interspersed with 15 s of passive recovery) performance were assessed before and after the training intervention. Total distance covered (TD) and the percentage of distance decrement (%Dec) were calculated for RS. Between-sprints muscle reoxygenation rate (Reoxy rate) was assessed with near-infrared spectroscopy during RS before and after training. After training, MAS (+9.8 ± 5.8%, with 100% chances to observe a substantial improvement), 10 km time (-6.2 ± 5.3%, 99%), TD (+9.6 ± 7.7%, 98%), %Dec (-25.6 ± 73.6%, 93%) and Reoxy rate (+152.4 ± 308.1%, 95%) were improved. The improvement of Reoxy rate was largely correlated with improvements in MAS [r = 0.63 (90% CL, 0.31;-0.82)] and %Dec [r = -0.52 (-0.15;-0.76)]. Present findings confirm the beneficial effect of endurance training on post-sprint muscle reoxygenation rate, which is likely to participate in the improvement of repeated-sprint ability after training. These data also confirm the importance of aerobic conditioning in sports, where repeating high-intensity/maximal efforts within a short time-period are required.

  7. The effects of 20-m repeated sprint training on aerobic capacity in college volleyball players

    Directory of Open Access Journals (Sweden)

    Kaynak Kerimhan

    2017-02-01

    Full Text Available Study aim: The purpose of this study was to examine the effects of a repeated sprint training program in addition to volleyball training on the aerobic capacity of college volleyball players.

  8. Endurance, aerobic high-intensity, and repeated sprint cycling performance is unaffected by normobaric "Live High-Train Low"

    DEFF Research Database (Denmark)

    Bejder, Jacob; Andersen, Andreas Breenfeldt; Buchardt, Rie

    2017-01-01

    The aim was to investigate whether 6 weeks of normobaric "Live High-Train Low" (LHTL) using altitude tents affect highly trained athletes incremental peak power, 26-km time-trial cycling performance, 3-min all-out performance, and 30-s repeated sprint ability. In a double-blinded, placebo...... conducted in a double-blinded, placebo-controlled cross-over design do not affect power output during an incremental test, a ~26-km time-trial test, or 3-min all-out exercise in highly trained triathletes. Furthermore, 30 s of repeated sprint ability was unaltered.......-out exercise, and 8 × 30 s of all-out sprint was evaluated before and after the intervention. Following at least 8 weeks of wash-out, the subjects crossed over and repeated the procedure. Incremental peak power output was similar after both interventions [LHTL: 375 ± 74 vs. 369 ± 70 W (pre-vs-post), placebo...

  9. Short- or long-rest intervals during repeated-sprint training in soccer?

    Science.gov (United States)

    Iaia, F Marcello; Fiorenza, Matteo; Larghi, Luca; Alberti, Giampietro; Millet, Grégoire P; Girard, Olivier

    2017-01-01

    The present study compared the effects of two repeated-sprint training (RST) programs, differing in duration of the between-sprint rest intervals, on various soccer-related exercise performances. For 5 weeks during the competitive season, twenty-nine young trained male soccer players either replaced two of their habitual fitness conditioning sessions with RST characterized by short (5-15; n = 9) or long (5-30; n = 10) rest intervals, or served as control (n = 10). The 5-15 and 5-30 protocols consisted of 6 repetitions of 30-m (~5 s) straight-line sprints interspersed with 15 s or 30 s of passive recovery, respectively. 5-15 improved 200-m sprint time (2.0±1.5%; psprint performance, whereas 5-30 lowered the 20-m sprint time (2.7±1.6%; psprint performance. The distance covered during the Yo-Yo Intermittent Recovery Test Level 2 increased following 5-15 (11.4±5.0%; prepeated-sprint ability test were possibly greater following 5-30 (3.6±0.9%; prepeated-sprint ability test as well as in blood lactate concentration during submaximal exercise (17-18%). No changes occurred in the control group. In soccer players, RST over a 5-week in-season period is an efficient means to simultaneously develop different components of fitness relevant to match performance, with different benefits induced by shorter compared to longer rest intervals.

  10. Effects of caffeine and carbohydrate mouth rinses on repeated sprint performance.

    Science.gov (United States)

    Beaven, C Martyn; Maulder, Peter; Pooley, Adrian; Kilduff, Liam; Cook, Christian

    2013-06-01

    Our purpose was to examine the effectiveness of carbohydrate and caffeine mouth rinses in enhancing repeated sprint ability. Previously, studies have shown that a carbohydrate mouth rinse (without ingestion) has beneficial effects on endurance performance that are related to changes in brain activity. Caffeine ingestion has also demonstrated positive effects on sprint performance. However, the effects of carbohydrate or caffeine mouth rinses on intermittent sprints have not been examined previously. Twelve males performed 5 × 6-s sprints interspersed with 24 s of active recovery on a cycle ergometer. Twenty-five milliliters of either a noncaloric placebo, a 6% glucose, or a 1.2% caffeine solution was rinsed in the mouth for 5 s prior to each sprint in a double-blinded and balanced cross-over design. Postexercise maximal heart rate and perceived exertion were recorded, along with power measures. A second experiment compared a combined caffeine-carbohydrate rinse with carbohydrate only. Compared with the placebo mouth rinse, carbohydrate substantially increased peak power in sprint 1 (22.1 ± 19.5 W; Cohen's effect size (ES), 0.81), and both caffeine (26.9 ± 26.9 W; ES, 0.71) and carbohydrate (39.1 ± 25.8 W; ES, 1.08) improved mean power in sprint 1. Experiment 2 demonstrated that a combination of caffeine and carbohydrate improved sprint 1 power production compared with carbohydrate alone (36.0 ± 37.3 W; ES, 0.81). We conclude that carbohydrate and (or) caffeine mouth rinses may rapidly enhance power production, which could have benefits for specific short sprint exercise performance. The ability of a mouth-rinse intervention to rapidly improve maximal exercise performance in the absence of fatigue suggests a central mechanism.

  11. Repeated-sprint performance and vastus lateralis oxygenation: effect of limited O₂ availability.

    Science.gov (United States)

    Billaut, F; Buchheit, M

    2013-06-01

    This study examined the influence of muscle deoxygenation and reoxygenation on repeated-sprint performance via manipulation of O2 delivery. Fourteen team-sport players performed 10 10-s sprints (30-s recovery) under normoxic (NM: FI O2 0.21) and acute hypoxic (HY: FI O2 0.13) conditions in a randomized, single-blind fashion and crossover design. Mechanical work was calculated and arterial O2 saturation (Sp O2 ) was estimated via pulse oximetry for every sprint. Muscle deoxyhemoglobin concentration ([HHb]) was monitored continuously by near-infrared spectroscopy. Differences between NM and HY data were analyzed for practical significance using magnitude-based inferences. HY reduced Sp O2 (-10.7 ± 1.9%, with chances to observe a higher/similar/lower value in HY of 0/0/100%) and mechanical work (-8.2 ± 2.1%; 0/0/100%). Muscle deoxygenation increased during sprints in both environments, but was almost certainly higher in HY (12.5 ± 3.1%, 100/0/0%). Between-sprint muscle reoxygenation was likely more attenuated in HY (-11.1 ± 11.9%; 2/7/91%). The impairment in mechanical work in HY was very largely correlated with HY-induced attenuation in muscle reoxygenation (r = 0.78, 90% confidence limits: 0.49; 0.91). Repeated-sprint performance is related, in part, to muscle reoxygenation capacity during recovery periods. These results extend previous findings that muscle O2 availability is important for prolonged repeated-sprint performance, in particular when the exercise is taken in hypoxia.

  12. The effects of oral creatine supplementation on performance in single and repeated sprint swimming.

    Science.gov (United States)

    Peyrebrune, M C; Nevill, M E; Donaldson, F J; Cosford, D J

    1998-04-01

    We studied the effects of oral creatine supplementation on sprint swimming performance in 14 elite competitive male swimmers. The subjects performed a single sprint (1 x 50 yards [45.72 m]) and repeated sprint set (8 x 50 yards at intervals of 1 min 30 s) before and after a 5 day period of either creatine (9 g creatine + 4.5 g maltodextrin + 4.5 g glucose day(-1)) or placebo (18 g glucose day(-1); double-blind protocol) supplementation. Venous and capillary blood samples were taken for the determination of plasma ammonia, blood pH and lactate. Mean times recorded for the single 50 yard sprint were unchanged as a result of supplementation (creatine vs control, N.S.). During the repeated sprint test, mean times increased (Pcreatine supplementation (sprints 1-8: control pre-, 23.35+/-0.68 to 26.32+/-1.34 s; control post-, 23.59+/-0.66 to 26.19+/-1.48 s; creatine pre-, 23.20+/-0.67 to 26.85+/-0.42 s; creatine post-, 23.39+/-0.54 to 25.73+/-0.26 s; P creatine supplementation (control, 12.7+/-5.7% vs 11.0+/-5.5%; creatine, 15.7+/-4.3% vs 10.0+/-2.5%; Pcreatine in this group of swimmers after an identical supplementation regimen. In summary, our results suggest that ingesting 9 g creatine per day for 5 days can improve swimming performance in elite competitors during repeated sprints, but appears to have no effect on a single 50 yard sprint.

  13. Effect of Beta alanine and sodium bicarbonate supplementation on repeated-sprint performance.

    Science.gov (United States)

    Ducker, Kagan J; Dawson, Brian; Wallman, Karen E

    2013-12-01

    This study aimed to investigate if combining beta alanine (BA) and sodium bicarbonate (NaHCO3) supplementation could lead to enhanced repeated-sprint performance in team-sport athletes, beyond what is possible with either supplement alone. Participants (n = 24) completed duplicate trials of a repeated-sprint test (3 sets; 6 × 20 m departing every 25 seconds, 4 minutes active recovery between sets) and were then allocated into 4 groups as follows: BA only (n = 6; 28 days BA, acute sodium chloride placebo); NaHCO3 only (n = 6; 28 days glucose placebo, acute NaHCO3); BA/NaHCO3 (n = 6; 28 days BA, acute NaHCO3); placebo only (n = 6; 28 days glucose placebo, acute sodium chloride placebo), then completed duplicate trials postsupplementation. Sodium bicarbonate alone resulted in moderate effect size (d = 0.40-0.71) and "likely" and "very likely" benefit for overall total sprint times (TST) and for each individual set and for first sprint (sets 2 and 3) and best sprint time (sets 2 and 3). Combining BA and NaHCO3 resulted in "possible" to "likely" benefits for overall TST and for sets 2 and 3. First sprint (set 3) and best sprint time (sets 2 and 3) also showed "likely" benefit after this trial. The BA and placebo groups showed no differences in performance after supplementation. In conclusion, these results indicate that supplementation with acute NaHCO3 improved repeated-sprint performance more than either a combination of NaHCO3 and BA or BA alone.

  14. Adaptation to Damaging Dance and Repeated-Sprint Activity in Women.

    Science.gov (United States)

    Brown, Meghan A; Howatson, Glyn; Keane, Karen M; Stevenson, Emma J

    2016-09-01

    Brown, MA, Howatson, G, Keane, KM, and Stevenson, EJ. Adaptation to damaging dance and repeated-sprint activity in women. J Strength Cond Res 30(9): 2574-2581, 2016-The repeated bout effect (RBE) refers to the prophylactic effect from damaging exercise after a single previous bout of exercise. There is a paucity of data examining the RBE in women, and investigations using exercise paradigms beyond isolated eccentric contractions are scarce. In light of the limited literature, this investigation aimed to determine whether 2 different sport-specific exercise bouts would elicit a RBE in women. Twenty-one female dancers (19 ± 1 years) completed either a dance-specific protocol (n = 10) or sport-specific repeated-sprint protocol (n = 11). Delayed-onset muscle soreness (DOMS), limb girths, creatine kinase (CK), countermovement jump height, reactive strength index, maximal voluntary contraction, and 30-meter sprint time were recorded before and 0, 24, 48, and 72 hours after exercise. An identical exercise bout was conducted approximately 4 weeks after the initial bout, during which time the subjects maintained habitual training and dietary behaviors. DOMS and 30-meter sprint time decreased after a second bout of both activities (p = 0.003; (Equation is included in full-text article.)= 0.38 and p = 0.008; and (Equation is included in full-text article.)= 0.31, respectively). Circulating CK was also lower at 24, 48, and 72 hours after the second bout, independent of group (p = 0.010 and (Equation is included in full-text article.)= 0.23). Compared with the repeated-sprint protocol, the magnitude of change in DOMS was greater after a subsequent bout of the dance protocol (p = 0.010 and (Equation is included in full-text article.)= 0.19). These data are the first to demonstrate that dance and repeated-sprint activity resulting in muscle damage in women confers a protective effect against muscle damage after a subsequent bout.

  15. Sex differences in acute translational repressor 4E-BP1 activity and sprint performance in response to repeated-sprint exercise in team sport athletes.

    Science.gov (United States)

    Dent, Jessica R; Edge, Johann A; Hawke, Emma; McMahon, Christopher; Mündel, Toby

    2015-11-01

    The physiological requirements underlying soccer-specific exercise are incomplete and sex-based comparisons are sparse. The aim of this study was to determine the effects of a repeated-sprint protocol on the translational repressor 4E-BP1 and sprint performance in male and female soccer players. Cross-over design involving eight female and seven male university soccer players. Participants performed four bouts of 6 × 30-m maximal sprints spread equally over 40 min. Heart rate, sprint time and sprint decrement were measured for each sprint and during the course of each bout. Venous blood samples and muscle biopsies from the vastus lateralis were taken at rest, at 15 min and 2h post-exercise. While males maintained a faster mean sprint time for each bout (P sprint performance for each bout (P sprint performance in males, with no sex differences for heart rate or lactate. Muscle analyses revealed sex differences in resting total (P repeated sprints. We show that females have a larger sprint decrement indicating that males have a superior ability to recover sprint performance. Sex differences in resting 4E-BP1 Thr37/46 suggest diversity in the training-induced phenotype of the muscle of males and females competing in equivalent levels of team-sport competition. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  16. The effect of heavy resistance exercise on repeated sprint performance in youth athletes.

    Science.gov (United States)

    Low, Daniel; Harsley, Paul; Shaw, Matthew; Peart, Daniel

    2015-01-01

    This investigation assessed whether prior heavy resistance exercise would improve the repeated sprint performance of 16 trained youth soccer players (Age 17.05 ± 0.65 years; height 182.6 ± 8.9 cm; body mass 77.8 ± 8.2 kg). In session 1, individual 1 repetition max was measured utilising a squat movement. In sessions 2 and 3, participants performed a running-based repeated anaerobic sprint test with and without prior heavy resistance exercise of 91% of their 1 repetition max. Times were recorded for each of the 6 sprints performed in the repeated sprint test and summed to provide total time. T-tests compared the two exercise conditions via differences in corresponding sprint times and total time. Analysis revealed significantly reduced total time with use of heavy resistance exercise (33.48 (±1.27) vs. 33.59 (±1.27); P = 0.01). Sprints 1 (P = 0.05) and 2 (P = 0.02) were also faster in the heavy resistance exercise condition (5.09 (±0.16) vs. 5.11 (±0.16) and 5.36 (±0.24) vs. 5.45 (±0.26) seconds respectively) although no other differences were shown. Findings demonstrate improved sprint times of trained adolescent soccer players after heavy resistance exercise although benefits appear not as sustained as in adult participants.

  17. Effects of red bull energy drink on repeated sprint performance in women athletes.

    Science.gov (United States)

    Astorino, Todd A; Matera, Angela J; Basinger, Jency; Evans, Mindy; Schurman, Taylor; Marquez, Rodney

    2012-05-01

    Energy drinks are frequently consumed by athletes prior to competition to improve performance. This study examined the effect of Red Bull™ on repeated sprint performance in women athletes. Fifteen collegiate soccer players participated, with mean age, height, and body mass equal to 19.5±1.1 year, 168.4±5.8 cm, and 63.4±6.1 kg, respectively. After performing a familiarization trial, subjects performed three sets of eight bouts of the modified t test after ingestion of 255 mL of placebo or Red Bull 1 h pre-exercise in a randomized, placebo-controlled crossover design. Throughout testing, sprint time, heart rate (HR), and rating of perceived exertion (RPE) were continuously obtained. Repeated measures analysis of variance was used to examine differences in variables between drink conditions. Across athletes, t test time ranged from 10.4 to 12.7 s. Mean sprint time was similar (p>0.05) between Red Bull (11.31±0.61 s) and placebo (11.35±0.61 s). HR and RPE increased (p0.05) of Red Bull on either variable versus placebo. Findings indicate that 255 mL of Red Bull containing 1.3 mg/kg of caffeine and 1 g of taurine does not alter repeated sprint performance, RPE, or HR in women athletes versus placebo. One serving of this energy drink provides no ergogenic benefit for women athletes engaging in sprint-based exercise.

  18. Comparison of Two Types of Warm-Up Upon Repeated-Sprint Performance in Experienced Soccer Players.

    Science.gov (United States)

    van den Tillaar, Roland; von Heimburg, Erna

    2016-08-01

    van den Tillaar, R and von Heimburg, E. Comparison of two types of warm-up upon repeated-sprint performance in experienced soccer players. J Strength Cond Res 30(8): 2258-2265, 2016-The aim of the study was to compare the effects of a long warm-up and a short warm-up upon repeated-sprint performance in soccer players. Ten male soccer players (age, 21.9 ± 1.9 years; body mass, 77.7 ± 8.3 kg; body height, 1.85 ± 0.03 m) conducted 2 types of warm-ups with 1 week in between: a long warm-up (20 minutes: LWup) and a short warm-up (10 minutes: SWup). Each warm-up was followed by a repeated-sprint test consisting of 8 × 30 m sprints with a new start every 30th second. The best sprint time, total sprinting time, and % decrease in time together with heart rate, lactate, and rate of perceived exertion (RPE) were measured. No significant differences in performance were found for the repeated-sprint test parameters (total sprint time: 35.99 ± 1.32 seconds [LWup] and 36.12 ± 0.96 seconds [SWup]; best sprint time: 4.32 ± 0.13 seconds [LWup] and 4.30 ± 0.10 seconds [SWup]; and % sprint decrease: 4.16 ± 2.15% [LWup] and 5.02 ± 2.07% [SWup]). No differences in lactate concentration after the warm-up and after the repeated-sprint test were found. However, RPE and heart rate were significantly higher after the long warm-up and the repeated-sprint test compared with the short warm-up. It was concluded that a short warm-up is as effective as a long warm-up for repeated sprints in soccer. Therefore, in regular training, less warm-up time is needed; the extra time could be used for important soccer skill training.

  19. A Clustered Repeated-Sprint Running Protocol for Team-Sport Athletes Performed in Normobaric Hypoxia

    Directory of Open Access Journals (Sweden)

    Jaime Morrison, Chris McLellan, Clare Minahan

    2015-12-01

    Full Text Available The present study compared the performance (peak speed, distance, and acceleration of ten amateur team-sport athletes during a clustered (i.e., multiple sets repeated-sprint protocol, (4 sets of 4, 4-s running sprints; i.e., RSR444 in normobaric normoxia (FiO2 = 0.209; i.e., RSN with normobaric hypoxia (FiO2 = 0.140; i.e., RSH. Subjects completed two separate trials (i. RSN, ii. RSH; randomised order between 48 h and 72 h apart on a non-motorized treadmill. In addition to performance, we examined blood lactate concentration [La-] and arterial oxygen saturation (SpO2 before, during, and after the RSR444. While there were no differences in peak speed or distance during set 1 or set 2, peak speed (p = 0.04 and 0.02, respectively and distance (p = 0.04 and 0.02, respectively were greater during set 3 and set 4 of RSN compared with RSH. There was no difference in the average acceleration achieved in set 1 (p = 0.45, set 2 (p = 0.26, or set 3 (p = 0.23 between RSN and RSH; however, the average acceleration was greater in RSN than RSH in set 4 (p < 0.01. Measurements of [La-] were higher during RSH than RSN immediately after Sprint 16 (10.2 ± 2.5 vs 8.6 ± 2.6 mM; p = 0.02. Estimations of SpO2 were lower during RSH than RSN, respectively, immediately prior to the commencement of the test (89.0 ± 2.0 vs 97.2 ± 1.5 %, post Sprint 8 (78.0 ± 6.3 vs 93.8 ± 3.6 % and post Sprint 16 (75.3 ± 6.3 vs 94.5 ± 2.5 %; all p < 0.01. In summary, the RSR444 is a practical protocol for the implementation of a hypoxic repeated-sprint training intervention into the training schedules of team-sport athletes. However, given the inability of amateur team-sport athletes to maintain performance in hypoxic (FiO2 = 0.140 conditions, the potential for specific training outcomes (i.e. speed to be achieved will be compromised, thus suggesting that the RSR444 should be used with caution.

  20. Advancing hypoxic training in team sports: from intermittent hypoxic training to repeated sprint training in hypoxia.

    Science.gov (United States)

    Faiss, Raphaël; Girard, Olivier; Millet, Grégoire P

    2013-12-01

    Over the past two decades, intermittent hypoxic training (IHT), that is, a method where athletes live at or near sea level but train under hypoxic conditions, has gained unprecedented popularity. By adding the stress of hypoxia during 'aerobic' or 'anaerobic' interval training, it is believed that IHT would potentiate greater performance improvements compared to similar training at sea level. A thorough analysis of studies including IHT, however, leads to strikingly poor benefits for sea-level performance improvement, compared to the same training method performed in normoxia. Despite the positive molecular adaptations observed after various IHT modalities, the characteristics of optimal training stimulus in hypoxia are still unclear and their functional translation in terms of whole-body performance enhancement is minimal. To overcome some of the inherent limitations of IHT (lower training stimulus due to hypoxia), recent studies have successfully investigated a new training method based on the repetition of short (training in hypoxia (RSH). The aims of the present review are therefore threefold: first, to summarise the main mechanisms for interval training and repeated sprint training in normoxia. Second, to critically analyse the results of the studies involving high-intensity exercises performed in hypoxia for sea-level performance enhancement by differentiating IHT and RSH. Third, to discuss the potential mechanisms underpinning the effectiveness of those methods, and their inherent limitations, along with the new research avenues surrounding this topic.

  1. Effects of Carbohydrate Ingestion and Carbohydrate Mouth Rinse on Repeat Sprint Performance.

    Science.gov (United States)

    Krings, Ben M; Peterson, Timothy J; Shepherd, Brandon D; McAllister, Matthew J; Smith, JohnEric W

    2017-06-01

    The purpose of this investigation was to examine to the influence of carbohydrate ingestion (CHOI) and carbohydrate mouth rinse (CHOR) on acute repeat maximal sprint performance. Fourteen healthy males (age: 21.7 ± 1.8 years, mass: 82.3 ± 12.3 kg) completed a total of five 15-s maximal repeat sprints on a cycle ergometer against 0.075 kg ・ kg(-1) body mass each separated by 4 min of active recovery. Subjects completed four experimental trials and were randomly assigned one of four treatments: (1) CHOI, (2) CHOR, (3) placebo mouth rinse (PLAR), (4) placebo ingestion (PLAI). Subjects rinsed or ingested six 50 mL 10% CHO solutions throughout each trial. Performance variables measured included rating of perceived exertion, peak heart rate, peak and mean power output, fatigue index, and total work. Significant treatment main effects were observed for mean power output (p = 0.026), total work (p = 0.020), fatigue index (p = 0.004), and heart rate (p = 0.013). Overall mean power output and total work were significantly greater with CHOI (659.3 ± 103.0 watts, 9849.8 ± 1598.8 joules) compared with CHOR (645.8 ± 99.7 watts, 9447.5 ± 1684.9 joules, p PLAI, and PLAR. Athletes required to complete repeat bouts of high intensity exercise may benefit from CHOI.

  2. Short- or long-rest intervals during repeated-sprint training in soccer?

    Science.gov (United States)

    Iaia, F. Marcello; Fiorenza, Matteo; Larghi, Luca; Alberti, Giampietro; Millet, Grégoire P.; Girard, Olivier

    2017-01-01

    The present study compared the effects of two repeated-sprint training (RST) programs, differing in duration of the between-sprint rest intervals, on various soccer-related exercise performances. For 5 weeks during the competitive season, twenty-nine young trained male soccer players either replaced two of their habitual fitness conditioning sessions with RST characterized by short (5–15; n = 9) or long (5–30; n = 10) rest intervals, or served as control (n = 10). The 5–15 and 5–30 protocols consisted of 6 repetitions of 30-m (~5 s) straight-line sprints interspersed with 15 s or 30 s of passive recovery, respectively. 5–15 improved 200-m sprint time (2.0±1.5%; psoccer players, RST over a 5-week in-season period is an efficient means to simultaneously develop different components of fitness relevant to match performance, with different benefits induced by shorter compared to longer rest intervals. PMID:28199402

  3. Effects of Beetroot Juice on Recovery of Muscle Function and Performance between Bouts of Repeated Sprint Exercise

    Directory of Open Access Journals (Sweden)

    Tom Clifford

    2016-08-01

    Full Text Available This study examined the effects of beetroot juice (BTJ on recovery between two repeated-sprint tests. In an independent groups design, 20 male, team-sports players were randomized to receive either BTJ or a placebo (PLA (2 × 250 mL for 3 days after an initial repeated sprint test (20 × 30 m; RST1 and after a second repeated sprint test (RST2, performed 72 h later. Maximal isometric voluntary contractions (MIVC, countermovement jumps (CMJ, reactive strength index (RI, pressure-pain threshold (PPT, creatine kinase (CK, C-reactive protein (hs-CRP, protein carbonyls (PC, lipid hydroperoxides (LOOH and the ascorbyl free radical (A•− were measured before, after, and at set times between RST1 and RST2. CMJ and RI recovered quicker in BTJ compared to PLA after RST1: at 72 h post, CMJ and RI were 7.6% and 13.8% higher in BTJ vs. PLA, respectively (p < 0.05. PPT was 10.4% higher in BTJ compared to PLA 24 h post RST2 (p = 0.012 but similar at other time points. No group differences were detected for mean and fastest sprint time or fatigue index. MIVC, or the biochemical markers measured (p > 0.05. BTJ reduced the decrement in CMJ and RI following and RST but had no effect on sprint performance or oxidative stress.

  4. Effects of Beetroot Juice on Recovery of Muscle Function and Performance between Bouts of Repeated Sprint Exercise.

    Science.gov (United States)

    Clifford, Tom; Berntzen, Bram; Davison, Gareth W; West, Daniel J; Howatson, Glyn; Stevenson, Emma J

    2016-08-18

    This study examined the effects of beetroot juice (BTJ) on recovery between two repeated-sprint tests. In an independent groups design, 20 male, team-sports players were randomized to receive either BTJ or a placebo (PLA) (2 × 250 mL) for 3 days after an initial repeated sprint test (20 × 30 m; RST1) and after a second repeated sprint test (RST2), performed 72 h later. Maximal isometric voluntary contractions (MIVC), countermovement jumps (CMJ), reactive strength index (RI), pressure-pain threshold (PPT), creatine kinase (CK), C-reactive protein (hs-CRP), protein carbonyls (PC), lipid hydroperoxides (LOOH) and the ascorbyl free radical (A(•-)) were measured before, after, and at set times between RST1 and RST2. CMJ and RI recovered quicker in BTJ compared to PLA after RST1: at 72 h post, CMJ and RI were 7.6% and 13.8% higher in BTJ vs. PLA, respectively (p sprint time or fatigue index. MIVC, or the biochemical markers measured (p > 0.05). BTJ reduced the decrement in CMJ and RI following and RST but had no effect on sprint performance or oxidative stress.

  5. A Clustered Repeated-Sprint Running Protocol for Team-Sport Athletes Performed in Normobaric Hypoxia.

    Science.gov (United States)

    Morrison, Jaime; McLellan, Chris; Minahan, Clare

    2015-12-01

    The present study compared the performance (peak speed, distance, and acceleration) of ten amateur team-sport athletes during a clustered (i.e., multiple sets) repeated-sprint protocol, (4 sets of 4, 4-s running sprints; i.e., RSR444) in normobaric normoxia (FiO2 = 0.209; i.e., RSN) with normobaric hypoxia (FiO2 = 0.140; i.e., RSH). Subjects completed two separate trials (i. RSN, ii. RSH; randomised order) between 48 h and 72 h apart on a non-motorized treadmill. In addition to performance, we examined blood lactate concentration [La(-)] and arterial oxygen saturation (SpO2) before, during, and after the RSR444. While there were no differences in peak speed or distance during set 1 or set 2, peak speed (p = 0.04 and 0.02, respectively) and distance (p = 0.04 and 0.02, respectively) were greater during set 3 and set 4 of RSN compared with RSH. There was no difference in the average acceleration achieved in set 1 (p = 0.45), set 2 (p = 0.26), or set 3 (p = 0.23) between RSN and RSH; however, the average acceleration was greater in RSN than RSH in set 4 (p Sprint 16 (10.2 ± 2.5 vs 8.6 ± 2.6 mM; p = 0.02). Estimations of SpO2 were lower during RSH than RSN, respectively, immediately prior to the commencement of the test (89.0 ± 2.0 vs 97.2 ± 1.5 %), post Sprint 8 (78.0 ± 6.3 vs 93.8 ± 3.6 %) and post Sprint 16 (75.3 ± 6.3 vs 94.5 ± 2.5 %; all p sprint training intervention into the training schedules of team-sport athletes. However, given the inability of amateur team-sport athletes to maintain performance in hypoxic (FiO2 = 0.140) conditions, the potential for specific training outcomes (i.e. speed) to be achieved will be compromised, thus suggesting that the RSR444 should be used with caution. Key pointsThe RSR444 is a practical, multiple-set repeated-sprint running protocol designed for team-sport athletes.During performance of the RSR444 in hypoxia (FiO2 = 0.140), amateur team-sport athletes were unable to replicate the peak speed, distance covered or

  6. Effects of combined creatine and sodium bicarbonate supplementation on repeated sprint performance in trained men.

    Science.gov (United States)

    Barber, James J; McDermott, Ann Y; McGaughey, Karen J; Olmstead, Jennifer D; Hagobian, Todd A

    2013-01-01

    Creatine and sodium bicarbonate supplementation independently increase exercise performance, but it remains unclear whether combining these 2 supplements is more beneficial on exercise performance. The purpose of this study was to evaluate the impact of combining creatine monohydrate and sodium bicarbonate supplementation on exercise performance. Thirteen healthy, trained men (21.1 ± 0.6 years, 23.5 ± 0.5 kg·m(-2), 66.7 ± 5.7 ml·(kg·m)(-1) completed 3 conditions in a double-blinded, crossover fashion: (a) Placebo (Pl; 20 g maltodextrin + 0.5 g·kg(-1) maltodextrin), (b) Creatine (Cr; 20 g + 0.5 g·kg(-1) maltodextrin), and (c) Creatine plus sodium bicarbonate (Cr + Sb; 20 g + 0.5 g·kg(-1) sodium bicarbonate). Each condition consisted of supplementation for 2 days followed by a 3-week washout. Peak power, mean power, relative peak power, and bicarbonate concentrations were assessed during six 10-second repeated Wingate sprint tests on a cycle ergometer with a 60-second rest period between each sprint. Compared with Pl, relative peak power was significantly higher in Cr (4%) and Cr + Sb (7%). Relative peak power was significantly lower in sprints 4-6, compared with that in sprint 1, in both Pl and Cr. However, in Cr + Sb, sprint 6 was the only sprint significantly lower compared with sprint 1. Pre-Wingate bicarbonate concentrations were significantly higher in Cr + Sb (10%), compared with in Pl and Cr, and mean concentrations remained higher after sprint 6, although not significantly. Combining creatine and sodium bicarbonate supplementation increased peak and mean power and had the greatest attenuation of decline in relative peak power over the 6 repeated sprints. These data suggest that combining these 2 supplements may be advantageous for athletes participating in high-intensity, intermittent exercise.

  7. Repeated sprint swimming performance after low- or high-intensity active and passive recoveries.

    Science.gov (United States)

    Toubekis, Argyris G; Adam, Georgios V; Douda, Helen T; Antoniou, Panagiotis D; Douroundos, Ioannis I; Tokmakidis, Savvas P

    2011-01-01

    The purpose of this study was to examine the effects on sprint swimming performance after low- and high-intensity active recovery (AR) as compared to passive recovery. Ten male competitive swimmers (age: 17.9 ± 2.3 years; body mass: 73.2 ± 4.0 kg; height: 1.81 ± 0.04 m, 100-m best time: 54.90 ± 1.96 seconds) performed 8 × 25-m sprints with 120-second rest intervals followed by a 50-m sprint 6 minutes later. During the 120-second and the 6-minute interval periods swimmers rested passively (PAS) or swam at an intensity of 40% (ACT40; 36 ± 8% of the V(O2)max) and 60% (ACT60; 59 ± 7% of the V(O2)max) of their individual 100-m velocity. Performance time of the 8 × 25-m after ACT60 was slower compared with PAS and ACT40, but no difference was observed between ACT40 and PAS conditions (PAS: 12.15 ± 0.48, ACT40: 12.23 ± 0.54, ACT60: 12.35 ± 0.57 seconds, p sprint was no different between conditions (PAS: 26.45 ± 0.91; ACT40: 26.30 ± 1.18; ACT60: 26.21 ± 1.19 seconds; p > 0.05). Blood lactate concentration was not different between PAS, ACT40, and ACT60 after the 8 × 25-m and the 50-m sprints (p > 0.05). Passive recovery, or low intensity of AR (40% of the 100-m velocity), is advised to maintain repeated 25-m sprint swimming performance when a 2-minute interval period is provided. Active recovery at an intensity corresponding to 60% of the 100-m velocity decreases performance during the 25-m repeated sprints without affecting the performance time on a subsequent longer duration sprint (i.e., 50 m).

  8. Mechanical work accounts for sex differences in fatigue during repeated sprints.

    Science.gov (United States)

    Billaut, François; Bishop, David J

    2012-04-01

    To investigate whether the larger reduction in mechanical work observed during repeated-sprint exercise (RSE) in men versus women represents a true, physiological sex dimorphism or is the consequence of the higher initial mechanical work performed by men. Male and female team-sport athletes (n = 35) performed 20, 5-s cycle sprints interspersed with 25 s of rest. Mechanical work and surface electromyograms (EMG) of four muscles were recorded in every sprint. Mechanical work achieved in one sprint (20.7%, P = 0.0006), total work accumulated over the 20 sprints (21.1%, P = 0.009) and percent work decrement (32.2%, P = 0.008) were larger in men than in women. When both sexes were plotted together, there was a positive relationship between the initial-sprint work and the work decrement across sprint repetitions (r = 0.89, P = 0.002). The RSE induced larger (P = 0.009) absolute EMG amplitude changes in men (-155.2 ± 60.3 mVs) than in women (-102.5 ± 45.1 mVs). Interestingly, in a subset of men and women (n = 7 per group) matched for initial-sprint work, the sex difference in percent work decrement (men: -29.5 ± 1.5%; women: -27.2 ± 3.2%; P = 0.72) and EMG changes (men: -17.7 ± 6.9% vs. women: -15.3 ± 7.1%; P = 0.69) no longer persisted. Results show that the proposed greater fatigue in men is likely to be a consequence of their greater absolute initial-sprint performance, rather than a sex difference in fatigue resistance per se. We conclude that, on the basis of the absolute mechanical work completed, women are not more fatigue resistant than men and use comparable muscle recruitment strategies to perform RSE.

  9. Effect of the number of sprint repetitions on the variation of blood lactate concentration in repeated sprint sessions.

    Science.gov (United States)

    Gharbi, Z; Dardouri, W; Haj-Sassi, R; Castagna, C; Chamari, K; Souissi, N

    2014-06-01

    The aim of the present study was to examine the effect of number of sprint repetitions on the variation of blood lactate concentration (blood [La]) during different repeated-sprint sessions in order to find the appropriate number of sprint repetitions that properly simulates the physiological demands of team sport competitions. Twenty male team-sport players (age, 22.2 ± 2.9 years) performed several repeated-sprint sessions (RSS) consisting of 1, 2, 3, 4, 5, 9, or 10 repetitions of 30 m shuttle sprints (2 × 15 m) with 30 s recovery in between. The blood [La] was obtained after 3 min of recovery at the end of each RSS. The present study showed that for RSS of 3 sprints (RSS3) there was a high increase (psprints (9.6±1.4 and 10.5±1.9 mmol · l(-1), p=0.96 and 0.26, respectively). After RSS9 and RSS10 blood [La] further significantly increased to 12.6 and 12.7 mmol · l(-1), psprint speed decrement (Sdec) (1.5±1.2; 2.0±1.1 and 2.6±1.4%, respectively). There was also no significant difference between RSS9 and RSS10 for Sdec (3.9±1.3% and 4.5±1.4%, respectively). In conclusion, the repeated-sprint protocol composed of 5 shuttle sprint repetitions is more representative of the blood lactate demands of the team sports game intensity.

  10. No Improved Performance With Repeated-Sprint Training in Hypoxia Versus Normoxia: A Double-Blind and Crossover Study.

    Science.gov (United States)

    Montero, David; Lundby, Carsten

    2017-02-01

    Few recent studies indicate that short-term repeated-sprint (RS) training in hypoxia (RSH) improves RS performance compared with identical training under normoxic conditions (RSN) in endurance-trained subjects. To determine the effects of RSH against RSN on RS performance under normoxic and moderate hypoxic conditions, using a randomized, doubleblind, crossover experimental design. Fifteen endurance-trained male subjects (age 25 ± 4 y) performed 4 wk of RS training (3 sessions/wk) in normobaric hypoxia (RSH, FiO2 = 13.8%) and normoxia (RSN, FiO2 = 20.9%) in a crossover manner. Before and after completion of training, RS tests were performed on a cycle ergometer with no prior exercise (RSNE), after an incremental exercise test (RSIE), and after a time-trial test (RSTT) in normoxia and hypoxia. Peak power outputs at the incremental exercise test and time-trial performance were unaltered by RSH in normoxia and hypoxia. RS performance was generally enhanced by RSH, as well as RSN, but there were no additional effects of RSH over RSN on peak and mean sprint power output and the number of repeated sprints performed in the RSNE, RSIE, and RSTT trials under normoxic and hypoxic conditions. The present double-blind crossover study indicates that RSH does not improve RS performance compared with RSN in normoxic and hypoxic conditions in endurance-trained subjects. Therefore, caution should be exercised when proposing RSH as an advantageous method to improve exercise performance.

  11. 转化RSA为氢化可的松的新月弯胞霉筛选%SCREENING OF CURVULARIA LNATA WITH THE ABILITY OF BIOCONVERTING RSA TO HYDROCORTISONE SCREENING OF CURVULARIA LNATA WITH THE ABILITY OF BIOCONVERTING RSA TO HYDROCORTISONE

    Institute of Scientific and Technical Information of China (English)

    杜连祥; 王敏; 王赓; 孙烨

    2001-01-01

    A strain C4 with ability of bioconversion from steroid RSA to hydrocortisone was selected fron the soil sample. It was identifide as Cuvularia Iunata according its morphological characters of clump and individuals. The optimum culture medium was established by orthogonal experiments :glucose 10g ,soybean powder 10g,water 1000mL, pH6.5. Determined by silica gel chromatography and high-performance liquid chromatography, the bioconversion ratio of hydrocortisone was 34%. At the same tine, the percentage change of RSA,hydrocortisone and other byproducts were measured during the course of bioconversion.%从土样中筛选到1株能转化甾体化合物RSA(17α-羟基孕甾-4-烯-3,20-二酮-21-醋酸酯)生成氢可的松(11β,17a,2l-三羟基孕甾-4-烯-3,20-二酮)的C4菌株,经菌落形态与个体形态观察,初步鉴定为新月弯胞霉(curvularia lunata)。正交实验确定该菌株的最适培养基为:葡萄糖10g,黄豆粉10g,自来水1000mL,pH6.5.经硅胶层析和高交液相色谱测定,氢化可的松转化率为34%。同时还测定了转化过程中RSA、氢化可的松及其它副产物的百分含量的变化。

  12. Endurance, aerobic high-intensity, and repeated sprint cycling performance is unaffected by normobaric "Live High-Train Low": a double-blind placebo-controlled cross-over study.

    Science.gov (United States)

    Bejder, Jacob; Andersen, Andreas Breenfeldt; Buchardt, Rie; Larsson, Tanja Hultengren; Olsen, Niels Vidiendal; Nordsborg, Nikolai Baastrup

    2017-05-01

    The aim was to investigate whether 6 weeks of normobaric "Live High-Train Low" (LHTL) using altitude tents affect highly trained athletes incremental peak power, 26-km time-trial cycling performance, 3-min all-out performance, and 30-s repeated sprint ability. In a double-blinded, placebo-controlled cross-over design, seven highly trained triathletes were exposed to 6 weeks of normobaric hypoxia (LHTL) and normoxia (placebo) for 8 h/day. LHTL exposure consisted of 2 weeks at 2500 m, 2 weeks at 3000 m, and 2 weeks at 3500 m. Power output during an incremental test, ~26-km time trial, 3-min all-out exercise, and 8 × 30 s of all-out sprint was evaluated before and after the intervention. Following at least 8 weeks of wash-out, the subjects crossed over and repeated the procedure. Incremental peak power output was similar after both interventions [LHTL: 375 ± 74 vs. 369 ± 70 W (pre-vs-post), placebo: 385 ± 60 vs. 364 ± 79 W (pre-vs-post)]. Likewise, mean power output was similar between treatments as well as before and after each intervention for time trial [LHTL: 257 ± 49 vs. 254 ± 54 W (pre-vs-post), placebo: 267 ± 57 vs. 267 ± 52 W (pre-vs-post)], and 3-min all-out [LHTL: 366 ± 68 vs. 369 ± 72 W (pre-vs-post), placebo: 365 ± 66 vs. 355 ± 71 W (pre-vs-post)]. Furthermore, peak- and mean power output during repeated sprint exercise was similar between groups at all time points (n = 5). In conclusion, 6 weeks of normobaric LHTL using altitude tents simulating altitudes of 2500-3500 m conducted in a double-blinded, placebo-controlled cross-over design do not affect power output during an incremental test, a ~26-km time-trial test, or 3-min all-out exercise in highly trained triathletes. Furthermore, 30 s of repeated sprint ability was unaltered.

  13. Repeated sprints, high-intensity interval training, small-sided games: theory and application to field sports.

    Science.gov (United States)

    Hoffmann, James J; Reed, Jacob P; Leiting, Keith; Chiang, Chieh-Ying; Stone, Michael H

    2014-03-01

    Due to the broad spectrum of physical characteristics necessary for success in field sports, numerous training modalities have been used develop physical preparedness. Sports like rugby, basketball, lacrosse, and others require athletes to be not only strong and powerful but also aerobically fit and able to recover from high-intensity intermittent exercise. This provides coaches and sport scientists with a complex range of variables to consider when developing training programs. This can often lead to confusion and the misuse of training modalities, particularly in the development of aerobic and anaerobic conditioning. This review outlines the benefits and general adaptations to 3 commonly used and effective conditioning methods: high-intensity interval training, repeated-sprint training, and small-sided games. The goals and outcomes of these training methods are discussed, and practical implementations strategies for coaches and sport scientists are provided.

  14. Changes in repeated-sprint performance in relation to change in locomotor profile in highly-trained young soccer players.

    Science.gov (United States)

    Buchheit, Martin; Mendez-Villanueva, Alberto

    2014-01-01

    The aim of this study was to examine the effects of changes in maximal aerobic (MAS) and sprinting (MSS) speeds and the anaerobic reserve (ASR) on repeated-sprint performance. Two hundred and seventy highly-trained soccer players (14.5 ± 1.6 year) completed three times per season (over 5 years) a maximal incremental running test to approach MAS, a 40-m sprint with 10-m splits to assess MSS and a repeated-sprint test (10 × 30-m sprints), where best (RSb) and mean (RSm) sprint times, and percentage of speed decrement (%Dec) were calculated. ASR was calculated as MSS-MAS. While ∆RSb were related to ∆MSS and ∆body mass (r(2) = 0.42, 90%CL[0.34;0.49] for the overall multiple regression, n = 334), ∆RSm was also correlated with ∆MAS and ∆sum of 7 skinfolds (r(2) = 0.43 [0.35;0.50], n = 334). There was a small and positive association between ∆%Dec and ∆MAS (r(2) = 0.02 [-0.07;0.11], n = 334). Substantial ∆MSS and ∆MAS had a predictive value of 70 and 55% for ∆RSm, respectively. Finally, ∆ASR per se was not predictive of ∆RSm (Cohen's = +0.8 to -0.3 with increased ASR), but the greater magnitude of ∆RSm improvement was observed when MSS, MAS and ASR increased together (0.8 vs. +0.4 with ASR increased vs. not, additionally to MSS and MAS). Low-cost field tests aimed at assessing maximal sprinting and aerobic speeds can be used to monitor ∆RS performance.

  15. Repeated-sprint cycling does not induce respiratory muscle fatigue in active adults: measurements from the powerbreathe® inspiratory muscle trainer.

    Science.gov (United States)

    Minahan, Clare; Sheehan, Beth; Doutreband, Rachel; Kirkwood, Tom; Reeves, Daniel; Cross, Troy

    2015-03-01

    This study examined respiratory muscle strength using the POWERbreathe® inspiratory muscle trainer (i.e., 'S-Index') before and after repeated-sprint cycling for comparison with maximal inspiratory pressure (MIP) values obtained during a Mueller maneuver. The S-Index was measured during six trials across two sessions using the POWERbreathe® and MIP was measured during three trials in a single session using a custom-made manometer in seven recreationally active adults. Global respiratory muscle strength was measured using both devices before and after the performance of sixteen, 6-s sprints on a cycle ergometer. Intraclass correlation coefficients for the POWERbreathe® S-index indicated excellent (p Repeated-sprint cycling had no effect on respiratory muscle strength as measured by the POWERbreathe® (p > 0.99) and during the Mueller maneuver (p > 0.99). The POWERbreathe® S-Index is a moderately reliable, but not equivalent, measure of MIP determined during a Mueller maneuver. Furthermore, repeated-sprint cycling does not induce globalized respiratory muscle fatigue in recreationally-active adults. Key pointsThe S-Index as measured by the POWERbreathe® is a reliable measure of respiratory muscle strengthThe S-Index does not accurately reflect maximal inspiratory pressure obtained from a Mueller maneuverRepeated-sprint cycling does not induce respiratory muscle fatigue as measured by the POWERbreathe® and the Manometer.

  16. EFFECT OF PRE-COOLING ON REPEAT-SPRINT PERFORMANCE IN SEASONALLY ACCLIMATISED MALES DURING AN OUTDOOR SIMULATED TEAM-SPORT PROTOCOL IN WARM CONDITIONS

    Directory of Open Access Journals (Sweden)

    Carly J. Brade

    2013-09-01

    Full Text Available Whether precooling is beneficial for exercise performance in warm climates when heat acclimatised is unclear. The purpose of this study was to determine the effect of precooling on repeat-sprint performance during a simulated team-sport circuit performed outdoors in warm, dry field conditions in seasonally acclimatised males (n = 10. They performed two trials, one with precooling (PC; ice slushy and cooling jacket and another without (CONT. Trials began with a 30-min baseline/cooling period followed by an 80 min repeat-sprint protocol, comprising 4 x 20-min quarters, with 2 x 5-min quarter breaks and a 10-min half-time recovery/cooling period. A clear and substantial (negative; PC slower effect was recorded for first quarter circuit time. Clear and trivial effects were recorded for overall circuit time, third and fourth quarter sprint times and fourth quarter best sprint time, otherwise unclear and trivial effects were recorded for remaining performance variables. Core temperature was moderately lower (Cohen's d=0.67; 90% CL=-1.27, 0.23 in PC at the end of the precooling period and quarter 1. No differences were found for mean skin temperature, heart rate, thermal sensation, or rating of perceived exertion, however, moderate Cohen's d effect sizes suggested a greater sweat loss in PC compared with CONT. In conclusion, repeat- sprint performance was neither clearly nor substantially improved in seasonally acclimatised players by using a combination of internal and external cooling methods prior to and during exercise performed in the field in warm, dry conditions. Of practical importance, precooling appears unnecessary for repeat-sprint performance if athletes are seasonally acclimatised or artificially acclimated to heat, as it provides no additional benefit

  17. Low volume short duration high-intensity interval training and repeated sprint ability in Gaelic football players

    OpenAIRE

    Kelly, David

    2014-01-01

    Gaelic Football is the most popular sport in Ireland and is characterized by irregular changes of pace and high-intensity efforts interspersed with periods of light to moderate intensity activity. Speed, power and aerobic capacity are essential fitness components for optimal performance during match play. A high level of aerobic conditioning is required to generate and maintain power output during repeated high intensity activities. Study 1: Anthropometric, physiological, metabolic and en...

  18. Effect of pre-cooling on repeat-sprint performance in seasonally acclimatised males during an outdoor simulated team-sport protocol in warm conditions.

    Science.gov (United States)

    Brade, Carly J; Dawson, Brian T; Wallman, Karen E

    2013-01-01

    Whether precooling is beneficial for exercise performance in warm climates when heat acclimatised is unclear. The purpose of this study was to determine the effect of precooling on repeat-sprint performance during a simulated team-sport circuit performed outdoors in warm, dry field conditions in seasonally acclimatised males (n = 10). They performed two trials, one with precooling (PC; ice slushy and cooling jacket) and another without (CONT). Trials began with a 30-min baseline/cooling period followed by an 80 min repeat-sprint protocol, comprising 4 x 20-min quarters, with 2 x 5-min quarter breaks and a 10-min half-time recovery/cooling period. A clear and substantial (negative; PC slower) effect was recorded for first quarter circuit time. Clear and trivial effects were recorded for overall circuit time, third and fourth quarter sprint times and fourth quarter best sprint time, otherwise unclear and trivial effects were recorded for remaining performance variables. Core temperature was moderately lower (Cohen's d=0.67; 90% CL=-1.27, 0.23) in PC at the end of the precooling period and quarter 1. No differences were found for mean skin temperature, heart rate, thermal sensation, or rating of perceived exertion, however, moderate Cohen's d effect sizes suggested a greater sweat loss in PC compared with CONT. In conclusion, repeat- sprint performance was neither clearly nor substantially improved in seasonally acclimatised players by using a combination of internal and external cooling methods prior to and during exercise performed in the field in warm, dry conditions. Of practical importance, precooling appears unnecessary for repeat-sprint performance if athletes are seasonally acclimatised or artificially acclimated to heat, as it provides no additional benefit. Key PointsPre-cooling did not improve repeated sprint performance during a prolonged team-sport circuit in field conditions.If individuals are already heat acclimatised/acclimated, pre-cooling is

  19. The use of portable NIRS to measure muscle oxygenation and haemodynamics during a repeated sprint running test.

    Science.gov (United States)

    Jones, Ben; Hesford, Catherine M; Cooper, Chris E

    2013-01-01

    Portable near-infrared spectroscopy (NIRS) devices were originally developed for use in exercise and sports science by Britton Chance in the 1990s (the RunMan and microRunman series). However, only recently with the development of more robust, and wireless systems, has the routine use in elite sport become possible. As with the medical use of NIRS, finding applications of the technology that are relevant to practitioners is the key issue. One option is to use NIRS to track exercise training-induced adaptations in muscle. Portable NIRS devices enable monitoring during the normal 'field' routine uses to assess fitness, such as repeat sprint shuttle tests. Knowledge about the acute physiological responses to these specific tests has practical applications within team sport training prescription, where development of both central and peripheral determinants of high-intensity intermittent exercise needs to be considered. The purpose of this study was to observe NIRS-detected parameters during a repeat sprint test. We used the PortaMon, a two wavelength spatially resolved NIR spectrometer manufactured by Artinis Inc., to assess NIR changes in the gastrocnemius muscle of both the left and right leg during high-intensity running. Six university standard rugby players were assessed (age 20 ± 1.5 years; height 183 ± 1.0 cm; weight 89.4 ± 5.8 kg; body fat 12.2 ± 3.0 %); the subjects completed nine repeated shuttle runs, which incorporated forward, backward and change of direction movements. Individual sprint time, total time to complete test, blood lactate response (BL), heart rate values (HR) and haemoglobin variables (ΔHHb, ΔtHb, ΔHbO2 and ΔTSI%) were measured. Total time to complete the test was 260 ± 20 s, final blood lactate was 14.3 ± 2.8 mM, and maximal HR 182 ± 5 bpm. NIRS variables displayed no differences between right and left legs. During the test, the group-averaged data showed a clear decrease in HbO2 (max. decrease 11.41 ± 4.95 μM), increase in HHb

  20. Acute effects of a caffeine-taurine energy drink on repeated sprint performance of American college football players.

    Science.gov (United States)

    Gwacham, Nnamdi; Wagner, Dale R

    2012-04-01

    Consumption of energy drinks is common among athletes; however, there is a lack of research on the efficacy of these beverages for short-duration, intense exercise. The purpose of this research was to investigate the acute effects of a low-calorie caffeine-taurine energy drink (AdvoCare Spark) on repeated sprint performance and anaerobic power in National Collegiate Athletic Association Division I football players. Twenty football players (age 19.7 ± 1.8 yr, height 184.9 ± 5.3 cm, weight 100.3 ± 21.7 kg) participated in a double-blind, randomized crossover study in which they received the energy drink or an isoenergetic, isovolumetric, non-caffeinated placebo in 2 trials separated by 7 days. The Running Based Anaerobic Sprint Test, consisting of six 35-m sprints with 10 s of rest between sprints, was used to assess anaerobic power. Sprint times were recorded with an automatic electronic timer. The beverage treatment did not significantly affect power (F = 3.84, p = .066) or sprint time (F = 3.06, p = .097). However, there was a significant interaction effect between caffeine use and the beverage for sprint times (F = 4.62, p = .045), as well as for anaerobic power (F = 5.40, p = .032), indicating a confounding effect. In conclusion, a caffeine-taurine energy drink did not improve the sprint performance or anaerobic power of college football players, but the level of caffeine use by the athletes likely influenced the effect of the drink.

  1. Interaction of central and peripheral factors during repeated sprints at different levels of arterial O2 saturation.

    Directory of Open Access Journals (Sweden)

    François Billaut

    Full Text Available PURPOSE: To investigate the interaction between the development of peripheral locomotor muscle fatigue, muscle recruitment and performance during repeated-sprint exercise (RSE. METHOD: In a single-blind, randomised and cross-over design, ten male team-sport athletes performed two RSE (fifteen 5-s cycling sprints interspersed with 25 s of rest; power self-selected in normoxia and in acute moderate hypoxia (FIO2 0.138. Mechanical work, total electromyographic intensity (summed quadriceps electromyograms, RMSsum and muscle (vastus lateralis and pre-fontal cortex near-infrared spectroscopy (NIRS parameters were calculated for every sprint. Blood lactate concentration ([Lac(-] was measured throughout the protocol. Peripheral quadriceps fatigue was assessed via changes in potentiated quadriceps twitch force (ΔQtw,pot pre- versus post-exercise in response to supra-maximal magnetic femoral nerve stimulation. The central activation ratio (QCAR was used to quantify completeness of quadriceps activation. RESULTS: Compared with normoxia, hypoxia reduced arterial oxygen saturation (-13.7%, P=0.001, quadriceps RMSsum (-13.7%, P=0.022, QCAR (-3.3%, P=0.041 and total mechanical work (-8.3%, P=0.019. However, the magnitude of quadriceps fatigue induced by RSE was similar in the two conditions (ΔQtw,pot: -53.5% and -55.1%, P=0.71. The lower cycling performance in hypoxia occurred despite similar metabolic (muscle NIRS parameters and blood [Lac(-] and functional (twitch and M-wave muscle states. CONCLUSION: Results suggest that the central nervous system regulates quadriceps muscle recruitment and, thereby, performance to limit the development of muscle fatigue during intermittent, short sprints. This finding highlights the complex interaction between muscular perturbations and neural adjustments during sprint exercise, and further supports the presence of pacing during intermittent sprint exercise.

  2. Attentional and visual demands for sprint performance in non-fatigued and fatigued conditions: reliability of a repeated sprint test

    Directory of Open Access Journals (Sweden)

    Diercks Ron L

    2010-05-01

    Full Text Available Abstract Background Physical performance measures are widely used to assess physical function, providing information about physiological and biomechanical aspects of motor performance. However they do not provide insight into the attentional and visual demands for motor performance. A figure-of-eight sprint test was therefore developed to measure the attentional and visual demands for repeated-sprint performance. The aims of the study were: 1 to assess test-retest reliability of the figure-of-eight sprint test, and 2 to study the attentional and visual demands for sprint performance in a non-fatigued and fatigued condition. Methods Twenty-seven healthy athletes were included in the study. To determine test-retest reliability, a subgroup of 19 athletes performed the figure-of-eight sprint test twice. The figure-of-eight sprint test consisted of nine 30-second sprints. The sprint test consisted of three test parts: sprinting without any restriction, with an attention-demanding task, and with restricted vision. Increases in sprint times with the attention-demanding task or restricted vision are reflective of the attentional and visual demands for sprinting. Intraclass correlation coefficients (ICCs and mean difference between test and retest with 95% confidence limits (CL were used to assess test-retest reliability. Repeated-measures ANOVA were used for comparisons between the sprint times and fatigue measurements of the test parts in both a non-fatigued and fatigued condition. Results The figure-of-eight sprint test showed good test-retest reliability, with ICCs ranging from 0.75 to 0.94 (95% CL: 0.40-0.98. Zero lay within the 95% CL of the mean differences, indicating that no bias existed between sprint performance at test and retest. Sprint times during the test parts with attention-demanding task (P = 0.01 and restricted vision (P Conclusions High ICCs and the absence of systematic variation indicate good test-retest reliability of the figure

  3. New Weak Keys in RSA

    Institute of Scientific and Technical Information of China (English)

    WANG Baocang; LIU Shuanggen; HU Yupu

    2006-01-01

    The security of the RSA system with the prime pairs of some special form is investigated. A new special-purpose algorithm for factoring RSA numbers is proposed. The basic idea of the method is to factor RSA numbers by factoring a well-chosen quadratic polynomial with integral coefficients. When viewed as a general-purpose algorithm, the new algorithm has a high computational complexity. It is shown that the RSA number n=pq can be easily factored if p and q have the special form of p=as+b, q=cs+d, where a, b, c, d are relatively small numbers. Such prime pairs (p, q) are the weak keys of RSA, so when we generate RSA modulus, we should avoid using such prime pairs (p, q).

  4. Repeated-Sprint Cycling Does Not Induce Respiratory Muscle Fatigue in Active Adults: Measurements from The Powerbreathe® Inspiratory Muscle Trainer

    Directory of Open Access Journals (Sweden)

    Clare Minahan, Beth Sheehan, Rachel Doutreband, Tom Kirkwood, Daniel Reeves, Troy Cross

    2015-03-01

    Full Text Available This study examined respiratory muscle strength using the POWERbreathe® inspiratory muscle trainer (i.e., ‘S-Index’ before and after repeated-sprint cycling for comparison with maximal inspiratory pressure (MIP values obtained during a Mueller maneuver. The S-Index was measured during six trials across two sessions using the POWERbreathe® and MIP was measured during three trials in a single session using a custom-made manometer in seven recreationally active adults. Global respiratory muscle strength was measured using both devices before and after the performance of sixteen, 6-s sprints on a cycle ergometer. Intraclass correlation coefficients for the POWERbreathe® S-index indicated excellent (p 0.99 and during the Mueller maneuver (p > 0.99. The POWERbreathe® S-Index is a moderately reliable, but not equivalent, measure of MIP determined during a Mueller maneuver. Furthermore, repeated-sprint cycling does not induce globalized respiratory muscle fatigue in recreationally-active adults.

  5. The Effects of a Single Whole-Body Cryotherapy Exposure on Physiological, Performance, and Perceptual Responses of Professional Academy Soccer Players After Repeated Sprint Exercise.

    Science.gov (United States)

    Russell, Mark; Birch, Jack; Love, Thomas; Cook, Christian J; Bracken, Richard M; Taylor, Tom; Swift, Eamon; Cockburn, Emma; Finn, Charlie; Cunningham, Daniel; Wilson, Laura; Kilduff, Liam P

    2017-02-01

    Russell, M, Birch, J, Love, T, Cook, CJ, Bracken, RM, Taylor, T, Swift, E, Cockburn, E, Finn, C, Cunningham, D, Wilson, L, and Kilduff, LP. The effects of a single whole-body cryotherapy exposure on physiological, performance, and perceptual responses of professional academy soccer players after repeated sprint exercise. J Strength Cond Res 31(2): 415-421, 2017-In professional youth soccer players, the physiological, performance, and perceptual effects of a single whole-body cryotherapy (WBC) session performed shortly after repeated sprint exercise were investigated. In a randomized, counterbalanced, and crossover design, 14 habituated English Premier League academy soccer players performed 15 × 30 m sprints (each followed by a 10 m forced deceleration) on 2 occasions. Within 20 minutes of exercise cessation, players entered a WBC chamber (Cryo: 30 seconds at -60° C, 120 seconds at -135° C) or remained seated (Con) indoors in temperate conditions (∼25° C). Blood and saliva samples, peak power output (countermovement jump), and perceptual indices of recovery and soreness were assessed pre-exercise and immediately, 2-hour and 24-hour postexercise. When compared with Con, a greater testosterone response was observed at 2-hour (+32.5 ± 32.3 pg·ml, +21%) and 24-hour (+50.4 ± 48.9 pg·ml, +28%) postexercise (both P = 0.002) in Cryo (trial × treatment interaction: P = 0.001). No between-trial differences were observed for other salivary (cortisol and testosterone/cortisol ratio), blood (lactate and creatine kinase), performance (peak power output), or perceptual (recovery or soreness) markers (all trial × treatment interactions: P > 0.05); all of which were influenced by exercise (time effects: all P ≤ 0.05). A single session of WBC performed within 20 minutes of repeated sprint exercise elevated testosterone concentrations for 24 hours but did not affect any other performance, physiological, or perceptual measurements taken. Although unclear, WBC may be

  6. Simple Backdoors on RSA Modulus by Using RSA Vulnerability

    Science.gov (United States)

    Sun, Hung-Min; Wu, Mu-En; Yang, Cheng-Ta

    This investigation proposes two methods for embedding backdoors in the RSA modulus N=pq rather than in the public exponent e. This strategy not only permits manufacturers to embed backdoors in an RSA system, but also allows users to choose any desired public exponent, such as e=216+1, to ensure efficient encryption. This work utilizes lattice attack and exhaustive attack to embed backdoors in two proposed methods, called RSASBLT and RSASBES, respectively. Both approaches involve straightforward steps, making their running time roughly the same as that of normal RSA key-generation time, implying that no one can detect the backdoor by observing time imparity.

  7. SEB teams up with RSA

    Index Scriptorium Estoniae

    2011-01-01

    Globaalne kindlustusgrupp RSA ja SEB Pank teatasid 19. aprillil, et alustavad koostööd varakindlustustoodete pakkumisel SEB klientidele Eestis, mis tähendab seda, et RSAst saab ainus varakindlustuse pakkuja pangas

  8. SEB teams up with RSA

    Index Scriptorium Estoniae

    2011-01-01

    Globaalne kindlustusgrupp RSA ja SEB Pank teatasid 19. aprillil, et alustavad koostööd varakindlustustoodete pakkumisel SEB klientidele Eestis, mis tähendab seda, et RSAst saab ainus varakindlustuse pakkuja pangas

  9. The recovery of repeated-sprint exercise is associated with PCr resynthesis, while muscle pH and EMG amplitude remain depressed.

    Directory of Open Access Journals (Sweden)

    Alberto Mendez-Villanueva

    Full Text Available The physiological equivalents of power output maintenance and recovery during repeated-sprint exercise (RSE remain to be fully elucidated. In an attempt to improve our understanding of the determinants of RSE performance we therefore aimed to determine its recovery following exhaustive exercise (which affected intramuscular and neural factors concomitantly with those of intramuscular concentrations of adenosine triphosphate [ATP], phosphocreatine [PCr] and pH values and electromyography (EMG activity (a proxy for net motor unit activity changes. Eight young men performed 10, 6-s all-out sprints on a cycle ergometer, interspersed with 30 s of recovery, followed, after 6 min of passive recovery, by five 6-s sprints, again interspersed by 30 s of passive recovery. Biopsies of the vastus lateralis were obtained at rest, immediately after the first 10 sprints and after 6 min of recovery. EMG activity of the vastus lateralis was obtained from surface electrodes throughout exercise. Total work (TW, [ATP], [PCr], pH and EMG amplitude decreased significantly throughout the first ten sprints (P<0.05. After 6 min of recovery, TW during sprint 11 recovered to 86.3±7.7% of sprint 1. ATP and PCr were resynthesized to 92.6±6.0% and 85.3±10.3% of the resting value, respectively, but muscle pH and EMG amplitude remained depressed. PCr resynthesis was correlated with TW done in sprint 11 (r = 0.79, P<0.05 and TW done during sprints 11 to 15 (r = 0.67, P<0.05. There was a ∼2-fold greater decrease in the TW/EMG ratio in the last five sprints (sprint 11 to 15 than in the first five sprints (sprint 1 to 5 resulting in a disproportionate decrease in mechanical power (i.e., TW in relation to EMG. Thus, we conclude that the inability to produce power output during repeated sprints is mostly mediated by intramuscular fatigue signals probably related with the control of PCr metabolism.

  10. Mathematical Attacks on RSA Cryptosystem

    Directory of Open Access Journals (Sweden)

    Imad K. Salah

    2006-01-01

    Full Text Available In this paper some of the most common attacks against Rivest, Shamir, and Adleman (RSA cryptosystem are presented. We describe the integer factoring attacks, attacks on the underlying mathematical function, as well as attacks that exploit details in implementations of the algorithm. Algorithms for each type of attacks are developed and analyzed by their complexity, memory requirements and area of usage.

  11. EFFICIENT ASIC ARCHITECTURE OF RSA CRYPTOSYSTEM

    Directory of Open Access Journals (Sweden)

    Varun Nehru

    2014-05-01

    Full Text Available This paper presents a unified architecture design of the RSA cryptosystem i.e. RSA cryptoaccelerator along with key-pair generation. A structural design methodology for the same is proposed and implemented. The purpose is to design a complete cryptosystem efficiently with reduced hardware redundancy. Individual modular architectures of RSA, Miller-Rabin Test and Extended Binary GCD algorithm are presented and then they are integrated. Standard algorithm for RSA has been used. The RSA datapath has further been transformed into DPA resistant design. The simulation and implementation results using 180nm technology are shown and prove the validity of the architecture.

  12. RSA and its Correctness through Modular Arithmetic

    Science.gov (United States)

    Meelu, Punita; Malik, Sitender

    2010-11-01

    To ensure the security to the applications of business, the business sectors use Public Key Cryptographic Systems (PKCS). An RSA system generally belongs to the category of PKCS for both encryption and authentication. This paper describes an introduction to RSA through encryption and decryption schemes, mathematical background which includes theorems to combine modular equations and correctness of RSA. In short, this paper explains some of the maths concepts that RSA is based on, and then provides a complete proof that RSA works correctly. We can proof the correctness of RSA through combined process of encryption and decryption based on the Chinese Remainder Theorem (CRT) and Euler theorem. However, there is no mathematical proof that RSA is secure, everyone takes that on trust!.

  13. Combinations of resting RSA and RSA reactivity impact maladaptive mood repair and depression symptoms

    Science.gov (United States)

    Yaroslavsky, Ilya; Bylsma, Lauren M.; Rottenberg, Jonathan; Kovacs, Maria

    2013-01-01

    We examined whether the combined indices of respiratory sinus arrhythmia at rest (resting RSA) and in response to a sad film (RSA reactivity) predict effective and ineffective responses to reduce sadness (adaptive vs. maladaptive mood repair) in women with histories of juvenile-onset depression (n = 74) and no history of major mental disorders (n = 75). Structural equation models were used to estimate latent resting RSA, depression, and adaptive and maladaptive mood repair and to test the study hypotheses. Results indicated that combinations of resting RSA+RSA reactivity (RSA patterns) predicted maladaptive mood repair, which in turn, mediated the effects of RSA pattern on depression. Further, RSA patterns moderated the depressogenic effects of maladaptive mood repair. RSA patterns were unrelated to adaptive mood repair. Our findings suggest that mood repair is one mechanism through which physiological vulnerabilities adversely affect mental health. PMID:23827087

  14. Repeated sprint ability but not neuromuscular fatigue is dependent on short versus long duration recovery time between sprints in healthy males.

    Science.gov (United States)

    Monks, Michael R; Compton, Chris T; Yetman, Joseph D; Power, Kevin E; Button, Duane C

    2017-06-01

    During maximal intensity leg cycling sprints, previous research has shown that central and peripheral fatigue development occurs with various (sprints. The aim of the current study was to compare the development of neuromuscular fatigue during maximal intensity lower-body sprints interspersed with short and longer duration recovery periods. Crossover study. Ten participants completed 10, 10s sprints interspersed with either 30 or 180s of recovery. Peak power outputs were measured for each sprint. Maximal force, voluntary activation (VA) and evoked contractile properties of the knee extensors were measured at pre-sprint 1, post-sprint 5 and post-sprint 10. Perceived pain was also measured immediately following each sprint. Peak power output was significantly lower by 16.1±4.2% (psprint 10 with 30 compared to 180s of recovery. Irrespective of recovery time, maximal force, VA and potentiated twitch force decreased by 26.7±7.2% (psprint 1 to post-sprint 10. MVC and PT decreased by 17±4% (psprint 1 to post-sprint 5. Although decreases in peak power and increases in perceived pain were greater when sprints were interspersed with 30 compared to 180s of recovery, the development of neuromuscular fatigue of the knee extensors was similar. The results illustrate that peripheral fatigue developed early whereas central fatigue developed later in the sprint protocol, however the effect of recovery time on neuromuscular fatigue could be task specific. Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  15. A Provably Secure Asynchronous Proactive RSA Scheme

    Institute of Scientific and Technical Information of China (English)

    ZHANG Rui-shan; LI Qiang; CHEN Ke-fei

    2005-01-01

    The drawback of the first asynchronous proactive RSA scheme presented by Zhou in 2001, is that the se curity definition and security proof do not follow the approach of provable security. This paper presented a provably secure asynchronous proactive RSA scheme, which includes three protocols: initial key distribution protocol,signature generation protocol and share refreshing protocol. Taken these protocols together, a complete provably secure proactive RSA scheme was obtained. And the efficiency of the scheme is approximate to that of the scheme of Zhou.

  16. Improved Mask Protected DES using RSA Algorithm

    Directory of Open Access Journals (Sweden)

    Asha Latha S.

    2016-01-01

    Full Text Available The data encryption standard is a pioneering and farsighted standard which helped to set a new paradigm for encryption standards. But now DES is considered to be insecure for some application. Asymmetric mask protected DES is an advanced encryption method for effectively protecting the advanced DES. There are still probabilities to improve its security. This paper propose a method, which introduce a RSA key generation scheme in mask protected DES instead of plain key, which result in enhancement in the security of present asymmetric mask protected DES. We further propose a Vedic mathematical method of RSA implementation which reduce the complexity of computation in RSA block thereby resulting in reduced delay (four timesthat improves the performance of overall system. The software implementation was performed using Xilinx 13.2 and Model-Sim was used for the simulation environment.

  17. Revisiting Fermat's Factorization for the RSA Modulus

    CERN Document Server

    Gupta, Sounak

    2009-01-01

    We revisit Fermat's factorization method for a positive integer $n$ that is a product of two primes $p$ and $q$. Such an integer is used as the modulus for both encryption and decryption operations of an RSA cryptosystem. The security of RSA relies on the hardness of factoring this modulus. As a consequence of our analysis, two variants of Fermat's approach emerge. We also present a comparison between the two methods' effective regions. Though our study does not yield a new state-of-the-art algorithm for integer factorization, we believe that it reveals some interesting observations that are open for further analysis.

  18. Hardware modules of the RSA algorithm

    Directory of Open Access Journals (Sweden)

    Škobić Velibor

    2014-01-01

    Full Text Available This paper describes basic principles of data protection using the RSA algorithm, as well as algorithms for its calculation. The RSA algorithm is implemented on FPGA integrated circuit EP4CE115F29C7, family Cyclone IV, Altera. Four modules of Montgomery algorithm are designed using VHDL. Synthesis and simulation are done using Quartus II software and ModelSim. The modules are analyzed for different key lengths (16 to 1024 in terms of the number of logic elements, the maximum frequency and speed.

  19. Data Security With Colors Using Rsa

    Directory of Open Access Journals (Sweden)

    G. Sankara Rao,

    2014-04-01

    Full Text Available Data Security with Colors using RSA technique that integrates the RGB Color model with the well-known public key cryptographic algorithm RSA (Rivest, Shamir and Adleman. This model provides both confidentiality and authentication to the data sent across the network. RSA algorithm uses public key and private key to encrypt and decrypt the data and thus provides confidentiality. But the public key is known to everyone and so anyone can encrypt the data and send the message. Hence authentication of users is needed. In this technique we use RGB color model to provide authentication. Every user will have a unique color assigned to him. A sender must know the receiver’s color to send a message. The color value is encrypted using a key which is used as a password while decrypting the message. To decrypt the message, the receiver must provide his color values. If the decrypted color values and his color values are equal then the sender and receiver are send to be authentic. The data encryption and decryption follows RSA procedure. Thus both authentication and confidentiality are provided for the data.

  20. RSA algoritam i njegova praktična primena / RSA algorithm

    Directory of Open Access Journals (Sweden)

    Sonja R. Kuljanski

    2010-07-01

    Full Text Available RSA algoritam jeste algoritam sa javnim ključem koji uključuje tri koraka: generisanje ključa, enkripciju i dekripciju. RSA enkripciona šema je determinističaka što znači da se osnovni tekst uvek enkriptuje u isti šifrovani tekst za unapred zadati javni ključ. Da bi se izbegao ovaj problem, praktična implementacija RSA algoritma obično koristi neke strukture, kao što je dodavanje slučajnog teksta u samu poruku pre enkripcije. Ovo dodavanje obezbeđuje da osnovna poruka bude sigurna i da se može enkriptovati u veliki broj različitih šifrovanih poruka. Standardi, kao što je PKCS #1, pažljivo su dizajnirani tako da dodaju tekst u osnovnu poruku pre RSA same enkripcije. / RSA is an algorithm for public-key encryption. It is the first algorithm known to be suitable for encryption as well as digital signing. The RSA encryption scheme is deterministic in the sense that under a fixed public key, a particular plaintext is always encrypted to the same ciphertext. A deterministic encryption scheme (as opposed to a probabilistic encryption scheme is a cryptosystem which always produces the same ciphertext for a given plaintext and key, even over separate executions of the encryption algorithm. Probabilistic encryption uses randomness in an encryption algorithm, so that when encrypting the same message several times it will, in general, yield different ciphertexts.

  1. Dynamic RSA: Examining parasympathetic regulatory dynamics via vector-autoregressive modeling of time-varying RSA and heart period.

    Science.gov (United States)

    Fisher, Aaron J; Reeves, Jonathan W; Chi, Cyrus

    2016-07-01

    Expanding on recently published methods, the current study presents an approach to estimating the dynamic, regulatory effect of the parasympathetic nervous system on heart period on a moment-to-moment basis. We estimated second-to-second variation in respiratory sinus arrhythmia (RSA) in order to estimate the contemporaneous and time-lagged relationships among RSA, interbeat interval (IBI), and respiration rate via vector autoregression. Moreover, we modeled these relationships at lags of 1 s to 10 s, in order to evaluate the optimal latency for estimating dynamic RSA effects. The IBI (t) on RSA (t-n) regression parameter was extracted from individual models as an operationalization of the regulatory effect of RSA on IBI-referred to as dynamic RSA (dRSA). Dynamic RSA positively correlated with standard averages of heart rate and negatively correlated with standard averages of RSA. We propose that dRSA reflects the active downregulation of heart period by the parasympathetic nervous system and thus represents a novel metric that provides incremental validity in the measurement of autonomic cardiac control-specifically, a method by which parasympathetic regulatory effects can be measured in process.

  2. Privacy Protection in Cloud Using Rsa Algorithm

    Directory of Open Access Journals (Sweden)

    Amandeep Kaur

    2014-05-01

    Full Text Available The cloud computing architecture has been on high demand nowadays. The cloud has been successful over grid and distributed environment due to its cost and high reliability along with high security. However in the area of research it is observed that cloud computing still has some issues in security regarding privacy. The cloud broker provide services of cloud to general public and ensures that data is protected however they sometimes lag security and privacy. Thus in this work of research an architecture is developed to preserve the security in two phases that is by RSA algorithm and auto-backup policy. Keywords:-

  3. Compensation for occupational diseases in the RSA.

    Science.gov (United States)

    Myers, J E; Garisch, D; Cornell, J E

    1987-03-01

    Compensation legislation for occupational disease in the RSA is at present complex and non-uniform, and the administrative bodies that process compensation claims are understaffed. In this setting occupational disease, particularly in migrant workers who are often ignorant of their rights under the law, frequently goes uncompensated. General practitioners and medical officers need to be aware of the basic provisions in the law, and how to submit claims in the best interests of their patients. Some case studies are included to illustrate problematic areas. The responsibilities of doctors in the diagnosis and compensation of occupational diseases are addressed.

  4. The multi-dimension RSA and its low exponent security

    Institute of Scientific and Technical Information of China (English)

    曹珍富

    2000-01-01

    Using a well-known result of polynomial over the finite field , we show that the Euler-Fermat theorem holds in N[ x]. We present a multi-dimension RSA cryptosystem and point out that low exponent algorithm of attacking RSA is not suitable for the multi-dimension RSA. Therefore, it is believed that the security of the new cryptosystem is mainly based on the factorization of large integers.

  5. Emotion suppression moderates the quadratic association between RSA and executive function.

    Science.gov (United States)

    Spangler, Derek P; Bell, Martha Ann; Deater-Deckard, Kirby

    2015-09-01

    There is uncertainty about whether respiratory sinus arrhythmia (RSA), a cardiac marker of adaptive emotion regulation, is involved in relatively low or high executive function performance. In the present study, we investigated (a) whether RSA during rest and tasks predict both relatively low and high executive function within a larger quadratic association among the two variables, and (b) the extent to which this quadratic trend was moderated by individual differences in emotion regulation. To achieve these aims, a sample of ethnically and socioeconomically diverse women self-reported reappraisal and emotion suppression. They next experienced a 2-min resting period during which electrocardiogram (ECG) was continually assessed. In the next phase, the women completed an array of executive function and nonexecutive cognitive tasks while ECG was measured throughout. As anticipated, resting RSA showed a quadratic association with executive function that was strongest for high suppression. These results suggest that relatively high resting RSA may predict poor executive function ability when emotion regulation consumes executive control resources needed for ongoing cognitive performance. © 2015 Society for Psychophysiological Research.

  6. Universally Composable Proactive Threshold RSA Signature

    Institute of Scientific and Technical Information of China (English)

    HONG Xuan; CHEN Ke-fei; LONG Yu

    2008-01-01

    Recently some efforts were made towards capturing the security requirements within the composable security framework.This modeling has some significant advantages in designing and analyzing complex systems.The threshold signature was discussed and a definition was given based on the universal composability framework,which is proved to be equivalent to the standard security definition.Furthermore,a simple,efficient and proactive threshold RSA signature protocol was presented.It is proved to be correct,consistent and unforgeable relative to the environment that at most t-1 parties are corrupted in each proactive stage.It is also secure under the universal composability framework.It is a UC based security and is proved to be equivalent to the standard security.

  7. Broadcast encryption schemes based on RSA

    Institute of Scientific and Technical Information of China (English)

    MU Ning-bo; HU Yu-pu; OU Hai-wen

    2009-01-01

    Three broadcast schemes for small receiver set using the property of RSA modulus are presented. They can solve the problem of data redundancy when the size of receiver set is small. In the proposed schemes, the center uses one key to encrypt the message and can revoke authorization conveniently. Every authorized user only needs to store one decryption key of a constant size. Among these three schemes, the first one has indistinguishability against adaptive chosen ciphertext attack (IND-CCA2) secure, and any collusion of authorized users cannot produce a new decryption key but the sizes of encryption modulus and ciphertext are linear in the number of receivers. In the second scheme, the size of ciphertext is half of the first one and any two authorized users can produce a new decryption key, but the center can identify them using the traitor tracing algorithm. The third one is the most efficient but the center cannot identify the traitors exactly.

  8. High-intensity intermittent training in hypoxia: a double-blinded, placebo-controlled field study in youth football players.

    Science.gov (United States)

    Brocherie, Franck; Girard, Olivier; Faiss, Raphael; Millet, Grégoire P

    2015-01-01

    This study examined the effects of 5 weeks (∼60 minutes per training, 2 d·wk) of run-based high-intensity repeated-sprint ability (RSA) and explosive strength/agility/sprint training in either normobaric hypoxia repeated sprints in hypoxia (RSH; inspired oxygen fraction [FIO2] = 14.3%) or repeated sprints in normoxia (RSN; FIO2 = 21.0%) on physical performance in 16 highly trained, under-18 male footballers. For both RSH (n = 8) and RSN (n = 8) groups, lower-limb explosive power, sprinting (10-40 m) times, maximal aerobic speed, repeated-sprint (10 × 30 m, 30-s rest) and repeated-agility (RA) (6 × 20 m, 30-s rest) abilities were evaluated in normoxia before and after supervised training. Lower-limb explosive power (+6.5 ± 1.9% vs. +5.0 ± 7.6% for RSH and RSN, respectively; both p football players, the addition of 10 repeated-sprint training sessions performed in hypoxia vs. normoxia to their regular football practice over a 5-week in-season period was more efficient at enhancing RA ability (including direction changes), whereas it had no additional effect on improvements in lower-limb explosive power, maximal sprinting, and RSA performance.

  9. DETERMIN LARGE PRIME NUMBERS TO COMPUTE RSA SYSTEM PARAMETERS

    Directory of Open Access Journals (Sweden)

    Ioan Mang

    2008-05-01

    Full Text Available Cryptography, the secret writing, is probably same old as writing itself and has applications in data security insurance. There are cryptosystems where the encipher algorithm can be public. These are public key algorithms. Research on public key algorithms has been concerned with security aspects. The results of this research have induced sufficient confidence to apply public key cryptography a larger scale. The most used and checked public key-based cryptosystem was find by Rivest, Shamir and Adleman, so called RSA system. This paper shows the RSA algorithm. We have realised a program that is able to determine prime numbers with over 100 digits and compute RSA system parameters.

  10. On the Efficiency of Fast RSA Variants in Modern Mobile Phones

    CERN Document Server

    Hansen, Klaus; Olsen, Kim

    2010-01-01

    Modern mobile phones are increasingly being used for more services that require modern security mechanisms such as the public key cryptosystem RSA. It is, however, well known that public key cryptography demands considerable computing resources and that RSA encryption is much faster than RSA decryption. It is consequently an interesting question if RSA as a whole can be executed efficiently on modern mobile phones. In this paper, we explore the efficiency on modern mobile phones of variants of the RSA cryptosystem, covering CRT, MultiPrime RSA, MultiPower RSA, Rebalanced RSA and R Prime RSA by comparing the encryption and decryption time using a simple Java implementation and a typical RSA setup.

  11. RSA-Based Password-Authenticated Key Exchange, Revisited

    Science.gov (United States)

    Shin, Seonghan; Kobara, Kazukuni; Imai, Hideki

    The RSA-based Password-Authenticated Key Exchange (PAKE) protocols have been proposed to realize both mutual authentication and generation of secure session keys where a client is sharing his/her password only with a server and the latter should generate its RSA public/private key pair (e, n), (d, n) every time due to the lack of PKI (Public-Key Infrastructures). One of the ways to avoid a special kind of off-line (so called e-residue) attacks in the RSA-based PAKE protocols is to deploy a challenge/response method by which a client verifies the relative primality of e and φ(n) interactively with a server. However, this kind of RSA-based PAKE protocols did not give any proof of the underlying challenge/response method and therefore could not specify the exact complexity of their protocols since there exists another security parameter, needed in the challenge/response method. In this paper, we first present an RSA-based PAKE (RSA-PAKE) protocol that can deploy two different challenge/response methods (denoted by Challenge/Response Method1 and Challenge/Response Method2). The main contributions of this work include: (1) Based on the number theory, we prove that the Challenge/Response Method1 and the Challenge/Response Method2 are secure against e-residue attacks for any odd prime e (2) With the security parameter for the on-line attacks, we show that the RSA-PAKE protocol is provably secure in the random oracle model where all of the off-line attacks are not more efficient than on-line dictionary attacks; and (3) By considering the Hamming weight of e and its complexity in the. RSA-PAKE protocol, we search for primes to be recommended for a practical use. We also compare the RSA-PAKE protocol with the previous ones mainly in terms of computation and communication complexities.

  12. Deterministic and Probabilistic Approach in Primality Checking for RSA Algorithm

    Directory of Open Access Journals (Sweden)

    Sanjoy Das

    2013-04-01

    Full Text Available The RSA cryptosystem, invented by Ron Rivest, Adi Shamir and Len Adleman was first publicized in the August 1977 issue of Scientific American [1]. The security level of this algorithm very much depends on two large prime numbers [2]. In this paper two distinct approaches have been dealt with for primality checking. These are deterministic approach and probabilistic approach. For the deterministic approach, it has chosen modified trial division and for probabilistic approach, Miller-Rabin algorithm is considered. The different kinds of attacks on RSA and their remedy are also being discussed. This includes the chosen cipher text attacks, short private key exponent attack and frequency attack. Apart from these attacks, discussion has been made on how to choose the primes for the RSA algorithm. The time complexity has been demonstrated for the various algorithms implemented and compared with others. Finally the future modifications and expectations arising out of the current limitations have also been stated at the end.

  13. Security analysis of RSA cryptosystem algorithm and it's properties

    Science.gov (United States)

    Liu, Chenglian; Guo, Yongning; Lin, Juan

    2014-10-01

    The information technology rapidly development and dramatically changed the life style people, in addition to shortening the distance of communication, but also promote the smooth exchange of information flows. However, derivatives to facilitate the relative safety of these issues, since into the digital information age, the majority of the practitioners of engineering and technical personnel and technical workers in terms of technology, information security is increasingly becoming an important issue. The RSA algorithm was published in 1978. It is a kind of very popular and widely application modem cryptosystem in the world. Even though there are lots of articles to discuss about how to break the RSA, but it is still secure today. In this paper, the authors would like to introduce a variant attack to RSA.

  14. A New Factorization Method to Factorize RSA Public Key Encryption

    Directory of Open Access Journals (Sweden)

    Bhagvant Ram Ambedkar

    2011-11-01

    Full Text Available The security of public key encryption such as RSA scheme relied on the integer factoring problem. The security of RSA algorithm is based on positive integer N, because each transmitting node generates pair of keys such as public and private. Encryption and decryption of any message depends on N. Where, N is the product of two prime numbers and pair of key generation is dependent on these prime numbers. The factorization of N is very intricate. In this paper a New Factorization method is proposed to obtain the factor of positive integer N. The proposed work focuses on factorization of all trivial and nontrivial integer numbers and requires fewer steps for factorization process of RSA modulus N. The New Factorization method is based on Pollard rho factorization method. Experimental results shown that factorization speed is fast as compare existing methods.

  15. Batch Private Keys Generation for RSA in Security Communication Systems

    Institute of Scientific and Technical Information of China (English)

    CHEN Yun; CHEN Xin

    2005-01-01

    RSA public key cryptosystem is extensively used in information security systems.However, key generation for RSA cryptosystem requires multiplicative inversion over finite field, which has higher computational complexity, compared with either multiplication in common sense or modular multiplication over finite field. In order to improve the performance of key generation, we propose a batch private keys generation method in this paper. The method derives efficiency from cutting down multiplicative inversions over finite field. Theoretical analysis shows that the speed of batch private keys generation for s users is faster than that of s times solo private key generation. It is suitable for applications in those systems with large amount of users.

  16. MODEL KEAMANAN INFORMASI BERBASIS DIGITAL SIGNATURE DENGAN ALGORITMA RSA

    Directory of Open Access Journals (Sweden)

    Mohamad Ihwani

    2016-01-01

    Full Text Available Abstrak — Kerahasiaan dan keamanan data yang merupakan hal yang sangat penting, sehingga untuk menjaga kerahasiaan dan keamanan data perusahaan tersebut dapat dilakukan salah satunya dengan menggunakan teknik kriptografi. Digital Signature Algorithm (DSA merupakan salah satu kriptografi yang digunakan untuk nirpenyangkalan. DSA merupakan suatu tanda tangan elektronik yang dapat digunakan untuk membuktikan keaslian identitas pengirim atau penandatangan dari suatu pesan atau dokumen digital, namun DSA dengan fungsi hash tidak mengenkripsi plainteks asli sehingga, dikombinasikan dengan RSA.   Keywords :  Kriptografi, DSA, RSA.

  17. Efficient, Robust and Constant-Round Distributed RSA Key Generation

    DEFF Research Database (Denmark)

    Damgård, Ivan Bjerre; Mikkelsen, Gert Læssøe

    2010-01-01

    We present the first protocol for distributed RSA key generation which is constant round, secure against malicious adversaries and has a negligibly small bound on the error probability, even using only one iteration of the underlying primality test on each candidate number.......We present the first protocol for distributed RSA key generation which is constant round, secure against malicious adversaries and has a negligibly small bound on the error probability, even using only one iteration of the underlying primality test on each candidate number....

  18. The RSA Cryptoprocessor Hardware Implementation Based on Modified Montgomery Algorithm

    Institute of Scientific and Technical Information of China (English)

    CHEN Bo; WANG Xu; RONG Meng-tian

    2005-01-01

    RSA (Rivest-Shamir-Adleman)public-key cryptosystem is widely used in the information security area such as encryption and digital signature. Based on the modified Montgomery modular multiplication algorithm, a new architecture using CSA(carry save adder)was presented to implement modular multiplication. Compared with the popular modular multiplication algorithms using two CSA, the presented algorithm uses only one CSA, so it can improve the time efficiency of RSA cryptoprocessor and save about half of hardware resources for modular multiplication. With the increase of encryption data size n, the clock cycles for the encryption procedure reduce in T(n2) , compared with the modular multiplication algorithms using two CSA.

  19. 对 Shor 算法破解 RSA 的探讨%Discussion on Cracking RSA With Shor Algorithm

    Institute of Scientific and Technical Information of China (English)

    凃玲英; 胡一凡; 张洪涛; 代永涛; 熊红梅

    2015-01-01

    Since the randomness of Shor algorithm could lead to low success rate in cracking RSA.By analyzing the prin-ciple of Shor algorithm,characteristics of RSA public key password system and lots of data,the view that the way for quantum functional in randomly selecting value is regular was putting forward .Verified by number theory and Monte Carlo method,the results showed that if takes a perfect square,the cycle probably can′t meet the requirements of Shor al-gorithm.It comes to a conclusion that take a non-perfect square can improve the success rate of Shor algorithm in cracking RSA.%针对 Shor 算法具有随机性,会导致破解 RSA 公钥密码体制成功率不高的问题,对 Shor 算法原理、RSA 公钥密码体制特点和大量计算结果进行分析,提出量子函数式 f (x)=ax mod n 对 a 值的随机选取是有规律的。结合数论知识和蒙特卡洛法证明,结果表明:随机数 a 取完全平方数,所求周期 r 很可能不满足 Shor算法要求;a 取非完全平方数可以提高 Shor 算法破解 RSA 的成功率。

  20. The mathematics of ciphers number theory and RSA cryptography

    CERN Document Server

    Coutinho, S C

    1999-01-01

    This book is an introduction to the algorithmic aspects of number theory and its applications to cryptography, with special emphasis on the RSA cryptosys-tem. It covers many of the familiar topics of elementary number theory, all with an algorithmic twist. The text also includes many interesting historical notes.

  1. Cryptanalysis of a Type of CRT-Based RSA Algorithms

    Institute of Scientific and Technical Information of China (English)

    Bao-Dong Qini; Ming Li; Fan-Yu Kong

    2008-01-01

    It is well known that the Chinese Remainder Theorem (CRT) can greatly improve the performances of RSA cryptosystem in both running times and memory requirements. However, if the implementation of CRT-based RSA is careless, an attacker can reveal some secret information by exploiting hardware fault cryptanalysis. In this paper, we present some fault attacks on a type of CRT-RSA algorithms namely BOS type schemes including the original BOS scheme proposed by Blomer, Otto, and Seifert at CCS 2003 and its modified scheme proposed by Liu et al. at DASC 2006. We first demonstrate that if some special signed messages such as m = 0, ±1 are dealt carelessly, they can be exploited by an adversary to completely break the security of both the BOS scheme and Liu et al.'s scheme. Then we present a new permanent fault attack on the BOS scheme with a success probability about 25%. Lastly, we propose a polynomial time attack on Liu et al.'s CRT-RSA algorithm, which combines physical fault injection and lattice reduction techniques when the public exponent is short.

  2. New generation of secure and practical RSA-based signatures

    NARCIS (Netherlands)

    R.J.F. Cramer (Ronald)

    1995-01-01

    textabstractFor most digital signature schemes used in practice, such as ISO9796/RSA or DSA, it has only been shown that certain plausible cryptographic assumptions, such as the difficulty of factoring integers, computing discrete logarithms or the collision-intractability of certain hash-functions

  3. RSA/Legacy Wind Sensor Comparison. Part 1; Western Range

    Science.gov (United States)

    Short, David A.; Wheeler, Mark M.

    2006-01-01

    This report describes a comparison of data from ultrasonic and cup-and-vane anemometers on 5 wind towers at Vandenberg AFB. The ultrasonic sensors are scheduled to replace the Legacy cup-and-vane sensors under the Range Standardization and Automation (RSA) program. Because previous studies have noted differences between peak wind speeds reported by mechanical and ultrasonic wind sensors, the latter having no moving parts, the 30th and 45th Weather Squadrons wanted to understand possible differences between the two sensor types. The period-of-record was 13-30 May 2005. A total of 153,961 readings of I-minute average and peak wind speed/direction from each sensor type were used. Statistics of differences in speed and direction were used to identify 18 out of 34 RSA sensors having the most consistent performance, with respect to the Legacy sensors. Data from these 18 were used to form a composite comparison. A small positive bias in the composite RSA average wind speed increased from +0.5 kts at 15 kts, to +1 kt at 25 kts. A slightly larger positive bias in the RSA peak wind speed increased from +1 kt at 15 kts, to +2 kts at 30 kts.

  4. RSA/Legacy Wind Sensor Comparison. Part 2; Eastern Range

    Science.gov (United States)

    Short, David A.; Wheeler, Mark M.

    2006-01-01

    This report describes a comparison of data from ultrasonic and propeller-and-vane anemometers on 5 wind towers at Kennedy Space Center and Cape Canaveral Air Force Station. The ultrasonic sensors are scheduled to replace the Legacy propeller-and-vane sensors under the Range Standardization and Automation (RSA) program. Because previous studies have noted differences between peak wind speeds reported by mechanical and ultrasonic wind sensors, the latter having no moving parts, the 30th and 45th Weather Squadrons wanted to understand possible differences between the two sensor types. The period-of-record was 13-30 May 2005, A total of 357,626 readings of 1-minute average and peak wind speed/direction from each sensor type were used. Statistics of differences in speed and direction were used to identify 15 out of 19 RSA sensors having the most consistent performance, with respect to the Legacy sensors. RSA average wind speed data from these 15 showed a small positive bias of 0.38 kts. A slightly larger positive bias of 0.94 kts was found in the RSA peak wind speed.

  5. Secure Batch Verification Protocol for RSA Signature Scheme

    Institute of Scientific and Technical Information of China (English)

    JIAZongpu; LIQingchao; LIZichen

    2005-01-01

    Harn, in 1998, proposed an efficient batch verification scheme for multiple RSA digital signatures.However, the scheme has a weakness, that is a signer can generate multiple signatures which can pass the batch verification scheme, but every one of these multiple signatures is not a valid signature. To avoid this disadvantage, we propose an improved batch verification scheme.

  6. On the Efficiency of Fast RSA Variants in Modern Mobile Phones

    DEFF Research Database (Denmark)

    Hansen, Klaus; Larsen, Troels; Olsen, Kim

    2009-01-01

    Modern mobile phones are increasingly being used for more services that require modern security mechanisms such as the public-key cryptosystem RSA. It is, however, well-known that public-key cryptography demands considerable computing resources and that RSA encryption is much faster than RSA...... decryption. It is consequently an interesting question if RSA as a whole can be executed efficiently on modern mobile phones....

  7. On the Efficiency of Fast RSA Variants in Modern Mobile Phones

    DEFF Research Database (Denmark)

    Hansen, Klaus; Larsen, Troels; Olsen, Kim

    2009-01-01

    Modern mobile phones are increasingly being used for more services that require modern security mechanisms such as the public-key cryptosystem RSA. It is, however, well-known that public-key cryptography demands considerable computing resources and that RSA encryption is much faster than RSA...... decryption. It is consequently an interesting question if RSA as a whole can be executed efficiently on modern mobile phones....

  8. Efficient and Robust Two-Party RSA Key Generation

    Institute of Scientific and Technical Information of China (English)

    YANG Muxiang; HONG Fan; ZHENG Minghui; LI Jun

    2006-01-01

    An efficient two party RSA secret key sharing generation scheme based on a homomorphic encryption, which is semantically secure under the prime residuosity assumption, is proposed in this paper. At the stage of computing RSA modulo N, an initial distributed primality test protocol is used to reduce the computation complexity and increase the probability of N being a two-prime product. On the other aspect, the homomorphic encryption based sharing conversion protocols is devised and adopted in multi-party computing modulus N and secret key d. Comparing to any sharing conversion protocols based on oblivious transfer protocol, the homomorphic encryption based sharing conversion protocols are of high performance. Our scheme resists the passive attack and since a method of verifying the sharing was introduced in, the scheme can resists any cheating behaviors too. Security proof, computation complexity and communication complexity analysis are given at last.

  9. APLIKASI KEAMANAN FILE AUDIO WAV (WAVEFORM DENGAN TERAPAN ALGORITMA RSA

    Directory of Open Access Journals (Sweden)

    Raja Nasrul Fuad

    2017-03-01

    Full Text Available The WAV file format that is widely used rough on various kinds of multimedia and gaming platforms. Ease of access and technological development with a variety of media to facilitate the exchange of information to various places. The data are important and need to be kept confidential secret for a wide range of security threats so that data can be intercepted and acknowledged by third parties during the shipping process. Of these problems led to the idea to create an application data security functions can secure the data using the RSA algorithm. The programming language is C # with Visual Studio software, the processed data is a sample each byte in WAV file, the header will be the same as that originally WAV files can be played even if the information has been withheld. RSA algorithm can be implemented into a programming language that WAV files can be processed and secured the data.

  10. Meteosat Images Encryption based on AES and RSA Algorithms

    Directory of Open Access Journals (Sweden)

    Boukhatem Mohammed Belkaid

    2015-06-01

    Full Text Available Satellite image Security is playing a vital role in the field of communication system and Internet. This work is interested in securing transmission of Meteosat images on the Internet, in public or local networks. To enhance the security of Meteosat transmission in network communication, a hybrid encryption algorithm based on Advanced Encryption Standard (AES and Rivest Shamir Adleman (RSA algorithms is proposed. AES algorithm is used for data transmission because of its higher efficiency in block encryption and RSA algorithm is used for the encryption of the key of the AES because of its management advantages in key cipher. Our encryption system generates a unique password every new session of encryption. Cryptanalysis and various experiments have been carried out and the results were reported in this paper, which demonstrate the feasibility and flexibility of the proposed scheme.

  11. A NEW RSA CRYPTOSYSTEM HARDWARE IMPLEMENTATION BASED ON MONTGOMERY'S ALGORITHM

    Institute of Scientific and Technical Information of China (English)

    卢君明; 林争辉

    2002-01-01

    RSA public key crypto-system is a relatively safe technology, which is widely used in today's secure electronic communication. In this paper, a new implementation method to optimize a 1 024 bit RSA processor was presented. Basically, a fast modular multiplication architecture based on Montgomery's algorithm was proposed. Modular exponentiation algorithm scans encryption from right to left, so two modular multiplications can be processed parallel. The new architecture is also fit for an effective I/O interface. The time to calculate a modular exponentiation is about n2 clock cycles. The proposed architecture has a data rate of 93.7 kb/s for 1 024 bit work with a 100 MHz clock.

  12. Adolescent RSA responses during an anger discussion task: Relations to emotion regulation and adjustment.

    Science.gov (United States)

    Cui, Lixian; Morris, Amanda Sheffield; Harrist, Amanda W; Larzelere, Robert E; Criss, Michael M; Houltberg, Benjamin J

    2015-06-01

    The current study examined associations between adolescent respiratory sinus arrhythmia (RSA) during an angry event discussion task and adolescents' emotion regulation and adjustment. Data were collected from 206 adolescents (10-18 years of age, M age = 13.37). Electrocardiogram (ECG) and respiration data were collected from adolescents, and RSA values and respiration rates were computed. Adolescents reported on their own emotion regulation, prosocial behavior, and aggressive behavior. Multilevel latent growth modeling was employed to capture RSA responses across time (i.e., linear and quadratic changes; time course approach), and adolescent emotion regulation and adjustment variables were included in the model to test their links to RSA responses. Results indicated that high RSA baseline was associated with more adolescent prosocial behavior. A pattern of initial RSA decreases (RSA suppression) in response to angry event recall and subsequent RSA increases (RSA rebound) were related to better anger and sadness regulation and more prosocial behavior. However, RSA was not significantly linked to adolescent aggressive behavior. We also compared the time course approach with the conventional linear approach and found that the time course approach provided more meaningful and rich information. The implications of adaptive RSA change patterns are discussed.

  13. Children's dynamic RSA change during anger and its relations with parenting, temperament, and control of aggression.

    Science.gov (United States)

    Miller, Jonas G; Chocol, Caroline; Nuselovici, Jacob N; Utendale, William T; Simard, Melissa; Hastings, Paul D

    2013-02-01

    This study examined the moderating effects of child temperament on the association between maternal socialization and 4-6-year-old children's dynamic respiratory sinus arrhythmia (RSA) change in response to anger-themed emotional materials (N=180). We used latent growth curve modeling to explore adaptive patterns of dynamic RSA change in response to anger. Greater change in RSA during anger-induction, characterized by more initial RSA suppression and a subsequent return to baseline, was related to children's better regulation of aggression. For anger-themed materials, low levels of authoritarian parenting predicted more RSA suppression and recovery for more anger-prone children, whereas more authoritative parenting predicted more RSA suppression and recovery for less anger-prone children. These findings suggest that children's adaptive patterns of dynamic RSA change can be characterized by latent growth curve modeling, and that these patterns may be differentially shaped by parent socialization experiences as a function of child temperament.

  14. Simplified Threshold RSA with Adaptive and Proactive Security

    DEFF Research Database (Denmark)

    Almansa Guerra, Jesus Fernando; Damgård, Ivan Bjerre; Nielsen, Jesper Buus

    2006-01-01

    We present the currently simplest, most efficient, optimally resilient, adaptively secure, and proactive threshold RSA scheme. A main technical contribution is a new rewinding strategy for analysing threshold signature schemes. This new rewinding strategy allows to prove adaptive security...... of a proactive threshold signature scheme which was previously assumed to be only statically secure. As a separate contribution we prove that our protocol is secure in the UC framework....

  15. An Efficient Proactive RSA Scheme for Ad Hoc Networks

    Institute of Scientific and Technical Information of China (English)

    ZHANG Rui-shan; CHEN Ke-fei

    2007-01-01

    A proactive threshold signature scheme is very important to tolerate mobile attack in mobile ad hoc networks. In this paper, we propose an efficient proactive threshold RSA signature scheme for ad hoc networks. The scheme consists of three protocols: the initial secret share distribution protocol, the signature generation protocol and the secret share refreshing protocol. Our scheme has three advantages. First, the signature generation protocol is efficient. Second, the signature generation protocol is resilient. Third, the share refreshing protocol is efficient.

  16. Reviews of computing technology: Securing network applications, Kerberos and RSA

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, S.M.

    1992-06-01

    This paper will focus on the first step in establishing network security, authentication, and describe the basic function of both RSA and Kerberos as used to provide authentication and confidential data transfer services. It will also discuss the Digital Signature Standard and the market acceptance of each. Proper identification of the principals involved in a network dialog is a necessary first step in providing network-wide security comparable to that of stand-alone systems.

  17. RSA Power Analysis Obfuscation: A Dynamic FPGA Architecture

    Science.gov (United States)

    2012-03-01

    research provides a VHDL coded dynamic architecture for synthesization on a Xilinx Virtex-5 FPGA. This architecture provides two-way communication...Component Under Test (CUT) is the dynamic RSA implementation. This dynamic hardware is synthesized from VHDL onto a Xilinx Virtex-5 FPGA. The built in...The hardware platform used for this research is a the Xil- inx Virtex-5 FX FPGA. VHDL code is synthesized using the Xilinx design suite and downloaded

  18. MODEL KEAMANAN INFORMASI BERBASIS DIGITAL SIGNATURE DENGAN ALGORITMA RSA

    Directory of Open Access Journals (Sweden)

    Mohamad Ihwani

    2016-01-01

    Full Text Available Kerahasiaan dan keamanan data yang merupakan hal yang sangat penting, sehingga untuk menjaga kerahasiaan dan keamanan data perusahaan tersebut dapat dilakukan salah satunya dengan menggunakan teknik kriptografi. Digital Signature Algorithm (DSA merupakan salah satu kriptografi yang digunakan untuk nirpenyangkalan. DSA merupakan suatu tanda tangan elektronik yang dapat digunakan untuk membuktikan keaslian identitas pengirim atau penandatangan dari suatu pesan atau dokumen digital, namun DSA dengan fungsi hash tidak mengenkripsi plainteks asli sehingga, dikombinasikan dengan RSA.

  19. Implementasi Algoritma Kriptografi RSA untuk Enkripsi dan Dekripsi Email

    Directory of Open Access Journals (Sweden)

    Albert Ginting

    2015-04-01

    Full Text Available In the world of Internet nothing is really safe. There's always a gap in any application made. Likewise in email delivery. To minimize attacks on the data transmission is usually applied cryptography. One fairly popular cryptographic algorithms are RSA algorithm. In this study will discuss the implementation of a cryptographic algorithm RSA encryption and decryption process email. To test created a java-based email client program with message encryption and decryption features messages. This application uses the Java programming language and Netbeans 7.4 as editor. Mail servers used is Google Mail. The initial step of this study was to download email from the Google server and encrypt the message. The second step is decrypt the message to verify whether the message is still the same as the original message before it is encrypted . Results from this study is the application that can encrypt and decrypt messages using RSA cryptographic algorithm. With this application is expected to mail delivery is much safer. Because encrypted email will generate a random decimal number of unknown value .

  20. Lattice Based Attack on Common Private Exponent RSA

    Directory of Open Access Journals (Sweden)

    Santosh Kumar Ravva

    2012-03-01

    Full Text Available Lattice reduction is a powerful concept for solving diverse problems involving point lattices. Lattice reduction has been successfully utilizing in Number Theory, Linear algebra and Cryptology. Not only the existence of lattice based cryptosystems of hard in nature, but also has vulnerabilities by lattice reduction techniques. In this paper, we show that Wieners small private exponent attack, when viewed as a heuristic lattice based attack, is extended to attack many instances of RSA when they have the same small private exponent.

  1. Information-Theoretic Secure Verifiable Secret Sharing over RSA Modulus

    Institute of Scientific and Technical Information of China (English)

    QIU Gang; WANG Hong; WEI Shimin; XIAO Guozhen

    2006-01-01

    The well-known non-interactive and information-theoretic secure verifiable secret sharing scheme presented by Pedersen is over a large prime. In this paper, we construct a novel non-interactive and information-theoretic verifiable secret sharing over RSA (Rivest,Shamir,Adleman) modulus and give the rigorous security proof. It is shown how to distribute a secret among a group such that any set of k parties get no information about the secret. The presented scheme is generally applied to constructions of secure distributed multiplication and threshold or forward-secure signature protocols.

  2. RSA2009参展厂商速递

    Institute of Scientific and Technical Information of China (English)

    王伟

    2009-01-01

    2009年RSA Conference参展商数量减少到了大约325个,但还是引入了一些新的板块和议题吸引参与者,如IN-NOVATION SANDBOX、物理安全和其他安全相关的热点讨论,参与这次展览的厂商涉及到从Physical Security、IT Security 到Policy Compliance的方方面面.

  3. Efficient RSA Key Generation and Threshold Paillier in the Two-Party Setting

    DEFF Research Database (Denmark)

    Hazay, Carmit; Mikkelsen, Gert Læssøe; Rabin, Tal

    2011-01-01

    The problem of generating an RSA composite in a distributed manner without leaking its factorization is particularly challenging and useful in many cryptographic protocols. Our first contribution is the first non-generic fully simulatable protocol for distributively generating an RSA composite...... generation is comprised of the following: (i) a distributed protocol for generation of an RSA composite, and (ii) a biprimality test for verifying the validity of the generated composite. Our Paillier threshold encryption scheme uses the RSA composite as public key and is comprised of: (i) a distributed...... generation of the corresponding secret-key shares and, (ii) a distributed decryption protocol for decrypting according to Paillier....

  4. Efficient RSA Key Generation and Threshold Paillier in the Two-Party Setting

    DEFF Research Database (Denmark)

    Hazay, Carmit; Mikkelsen, Gert Læssøe; Rabin, Tal

    2012-01-01

    The problem of generating an RSA composite in a distributed manner without leaking its factorization is particularly challenging and useful in many cryptographic protocols. Our first contribution is the first non-generic fully simulatable protocol for distributively generating an RSA composite...

  5. ECC over RSA for Asymmetric Encryption-A Review

    Directory of Open Access Journals (Sweden)

    Kamlesh Gupta

    2011-05-01

    Full Text Available Cryptography is used to transmit the data securely in open network. This paper gives the survey of Elliptic Curve Cryptosystem (ECC used in many applications. ECC is a when compared to RSA and discrete logarithm systems, is a better option for the future. For this reason ECC is such an excellent choice for doing asymmetric cryptography in portable devices right now. The smaller ECC keys it turn makes the cryptographic operations that must be performed by the communicating devices to be embedded into considerably smaller hardware, so that software applications may complete cryptographic operations with fewer processor cycles, and operations can be performed much faster, while still retaining equivalent security. This means, in turn, reduced power consumption, less space consumed on the printed circuit board, and software applications that run more rapidly make lower memory demands. In brief, for communication using smaller devices and asymmetric cryptosystem we need ECC.

  6. Diurnal Variations in Physical Performances Related to Football in Young Soccer Players

    OpenAIRE

    Chtourou, Hamdi; Hammouda, Omar; Souissi, Hichem; Chamari, Karim; Chaouachi, Anis; Souissi, Nizar

    2012-01-01

    Purpose This study investigated the effects of time-of-day on aerobic and anaerobic performances during the Yo-Yo, repeated sprint ability (RSA) and the Wingate tests in young soccer players. Methods In a counterbalanced and a random order, twenty junior male soccer players completed the Yo-Yo, the RSA, and the Wingate tests at two different times-of-day: 07:00 and 17:00 h. During the Yo-Yo test, the total distance (TD) covered and the estimated maximal aerobic velocity (MAV) were determined....

  7. A randomized RSA study concentrating especially on continuous migration.

    Science.gov (United States)

    Molt, Mats; Ryd, Leif; Toksvig-Larsen, Sören

    2016-06-01

    Background and purpose - There is a general call for phased introduction of new implants, and one step in the introduction is an early evaluation of micromotion. We compared the micromotion in the Triathlon and its predecessor, the Duracon total knee prosthesis, concentrating especially on continuous migration over 5 years of follow-up. Patients and methods - 60 patients were randomized to receive either a cemented Triathlon total knee prosthesis or a cemented Duracon total knee prosthesis. 3-D tibial component migration was measured by radiostereometric analysis (RSA) at 3 months and at 1, 2, and 5 years. Results - There was no statistically significant difference in maximum total point motion (MTPM) between the 2 groups (p = 0.1). The mean MTPM at 5 years for the Duracon was 1.10 (SD 1.21) mm and for the Triathlon it was 0.66 (SD 0.38) mm. The numbers of continuously migrating prostheses were similar in the groups at the fifth year of follow-up; 6 of 21 prostheses in the Duracon group and 3 of 21 in the Triathlon group had migrated more than 0.3 mm between the second year and the fifth year of follow-up (p = 0.2). Interpretation - The Triathlon has a micromotion pattern similar to that of the Duracon total knee system at both short-term and medium-term follow-up, and may therefore, over time, show the same good long-term mechanical stability.

  8. Improved Trial Division Technique for Primality Checking in RSA Algorithm

    Directory of Open Access Journals (Sweden)

    Kumarjit Banerjee

    2012-07-01

    Full Text Available The RSA cryptosystem, invented by Ron Rivest, Adi Shamir and Len Adleman was first publicized in the August 1977 issue of Scientific American. The security level of this algorithm very much depends on two large prime numbers. To check the primality of large number in personal computer is huge time consuming using the best known trial division algorithm. The time complexity for primality testing has been reduced using the representation of divisors in the form of 6n±1. According to the fundamental theorem of Arithmetic, every number has unique factorization. So to check primality, it is sufficient to check if the number is divisible by any prime below the square root of the number. The set of divisors obtained by 6n±1 form representation contains many composites. These composite numbers have been reduced by 30k approach. In this paper, the number of composites has been further reduced using 210k approach. A performance analysis in time complexity has been given between 210k approach and other prior applied methods. It has been observed that the time complexity for primality testing has been reduced using 210k approach.

  9. VLSI implementation of RSA encryption system using ancient Indian Vedic mathematics

    Science.gov (United States)

    Thapliyal, Himanshu; Srinivas, M. B.

    2005-06-01

    This paper proposes the hardware implementation of RSA encryption/decryption algorithm using the algorithms of Ancient Indian Vedic Mathematics that have been modified to improve performance. The recently proposed hierarchical overlay multiplier architecture is used in the RSA circuitry for multiplication operation. The most significant aspect of the paper is the development of a division architecture based on Straight Division algorithm of Ancient Indian Vedic Mathematics and embedding it in RSA encryption/decryption circuitry for improved efficiency. The coding is done in Verilog HDL and the FPGA synthesis is done using Xilinx Spartan library. The results show that RSA circuitry implemented using Vedic division and multiplication is efficient in terms of area/speed compared to its implementation using conventional multiplication and division architectures.

  10. VLSI Implementation of RSA Encryption System Using Ancient Indian Vedic Mathematics

    OpenAIRE

    2006-01-01

    This paper proposes the hardware implementation of RSA encryption/decryption algorithm using the algorithms of Ancient Indian Vedic Mathematics that have been modified to improve performance. The recently proposed hierarchical overlay multiplier architecture is used in the RSA circuitry for multiplication operation. The most significant aspect of the paper is the development of a division architecture based on Straight Division algorithm of Ancient Indian Vedic Mathematics and embedding it in...

  11. Are CT Scans a Satisfactory Substitute for the Follow-Up of RSA Migration Studies of Uncemented Cups? A Comparison of RSA Double Examinations and CT Datasets of 46 Total Hip Arthroplasties

    Directory of Open Access Journals (Sweden)

    Volker Otten

    2017-01-01

    Full Text Available As part of the 14-year follow-up of a prospectively randomized radiostereometry (RSA study on uncemented cup fixation, two pairs of stereo radiographs and a CT scan of 46 hips were compared. Tantalum beads, inserted during the primary operation, were detected in the CT volume and the stereo radiographs and used to produce datasets of 3D coordinates. The limit of agreement between the combined CT and RSA datasets was calculated in the same way as the precision of the double RSA examination. The precision of RSA corresponding to the 99% confidence interval was 1.36°, 1.36°, and 0.60° for X-, Y-, and Z-rotation and 0.40, 0.17, and 0.37 mm for X-, Y-, and Z-translation. The limit of agreement between CT and RSA was 1.51°, 2.17°, and 1.05° for rotation and 0.59, 0.56, and 0.74 mm for translation. The differences between CT and RSA are close to the described normal 99% confidence interval for precision in RSA: 0.3° to 2° for rotation and 0.15 to 0.6 mm for translation. We conclude that measurements using CT and RSA are comparable and that CT can be used for migration studies for longitudinal evaluations of patients with RSA markers.

  12. Longitudinal associations between temperament and socioemotional outcomes in young children: the moderating role of RSA and gender.

    Science.gov (United States)

    Morales, Santiago; Beekman, Charles; Blandon, Alysia Y; Stifter, Cynthia A; Buss, Kristin A

    2015-01-01

    Temperament is an important predictor of socioemotional adjustment, such as externalizing and internalizing symptoms. However, there is not a one-to-one correspondence between temperamental predispositions and these outcomes, implying that other factors also contribute to the development of internalizing and externalizing problems. Self-regulation is believed to interact with temperament, and has been studied as a predictor for later socioemotional outcomes. Respiratory sinus arrhythmia (RSA) is a psychophysiological measure of self-regulation that has been studied as a moderator of risk. The primary aim of the present study was to test if RSA baseline and RSA reactivity would moderate the link between temperament and socioemotional outcomes. Mothers reported the temperament of their infants (20 months; N = 154), RSA was collected at 24- and 42-months, and mothers reported externalizing and internalizing behaviors at kindergarten entry. RSA baseline and RSA reactivity moderated the relation between exuberant temperament and externalizing behaviors. However, these results were only significant for girls, such that high RSA baseline and greater RSA suppression predicted more externalizing behaviors when exuberance was high. Fearful temperament predicted later internalizing behaviors, but no moderation was present. These results are discussed in light of recent evidence regarding gender differences in the role of RSA as a protective factor for risk.

  13. Remarks on the bounds for cryptanalysis of low private key RSA

    Institute of Scientific and Technical Information of China (English)

    Haijian Zhou; Ping Luo; Daoshun Wang; Yiqi Dai

    2009-01-01

    Boneh and Durfee have developed a cryptanalytic algorithm on low private key RSA. The algorithm is based on lattice basis reduc-tion and breaks RSA with private key d < N0.292. Later on, an improved version by Blomer and May enhanced the efficiency, while reaching approximately this same upper bound. Unfortunately, in both the algorithms, there is a critical error in theoretical analysis, leading to the overestimated upper bound N0.292. In this paper we present a more precise analytical model, with which the theoretical upper bound on d is modified to approximately d < N0.277 for ordinary RSA systems with a 1024-bit public key (N, e).

  14. A Proposed Algorithm to improve security & Efficiency of SSL-TLS servers using Batch RSA decryption

    CERN Document Server

    Pateriya, R K; Shrivastava, S C; Patel, Jaideep

    2009-01-01

    Today, Internet becomes the essential part of our lives. Over 90 percent of the ecommerce is developed on the Internet. A security algorithm became very necessary for producer client transactions assurance and the financial applications safety. The rsa algorithm applicability derives from algorithm properties like confidentiality, safe authentication, data safety and integrity on the internet. Thus, this kind of networks can have a more easy utilization by practical accessing from short, medium, even long distance and from different public places. Rsa encryption in the client side is relatively cheap, whereas, the corresponding decryption in the server side is expensive because its private exponent is much larger. Thus ssl tls servers become swamped to perform public key decryption operations when the simultaneous requests increase quickly .The batch rsa method is useful for such highly loaded web server .In our proposed algorithm by reducing the response time and clients tolerable waiting time an improvement...

  15. Security analysis of RSA cryptosystem algorithm and it’s properties

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chenglian [School of Mathematics and Computer Science, Long Yan university, Lonyan 364012 (China); Guo, Yongning, E-mail: guoyn@163.com, E-mail: linjuanliucaihong@qq.com; Lin, Juan, E-mail: guoyn@163.com, E-mail: linjuanliucaihong@qq.com [Department of Mathematics and Computer Science, Fuqing Branch of Fujian Normal University, Fuqing 350300 (China)

    2014-10-06

    The information technology rapidly development and dramatically changed the life style people, in addition to shortening the distance of communication, but also promote the smooth exchange of information flows. However, derivatives to facilitate the relative safety of these issues, since into the digital information age, the majority of the practitioners of engineering and technical personnel and technical workers in terms of technology, information security is increasingly becoming an important issue. The RSA algorithm was published in 1978. It is a kind of very popular and widely application modem cryptosystem in the world. Even though there are lots of articles to discuss about how to break the RSA, but it is still secure today. In this paper, the authors would like to introduce a variant attack to RSA.

  16. Sprint vs. interval training in football.

    Science.gov (United States)

    Ferrari Bravo, D; Impellizzeri, F M; Rampinini, E; Castagna, C; Bishop, D; Wisloff, U

    2008-08-01

    The aim of this study was to compare the effects of high-intensity aerobic interval and repeated-sprint ability (RSA) training on aerobic and anaerobic physiological variables in male football players. Forty-two participants were randomly assigned to either the interval training group (ITG, 4 x 4 min running at 90 - 95 % of HRmax; n = 21) or repeated-sprint training group (RSG, 3 x 6 maximal shuttle sprints of 40 m; n = 21). The following outcomes were measured at baseline and after 7 weeks of training: maximum oxygen uptake, respiratory compensation point, football-specific endurance (Yo-Yo Intermittent Recovery Test, YYIRT), 10-m sprint time, jump height and power, and RSA. Significant group x time interaction was found for YYIRT (p = 0.003) with RSG showing greater improvement (from 1917 +/- 439 to 2455 +/- 488 m) than ITG (from 1846 +/- 329 to 2077 +/- 300 m). Similarly, a significant interaction was found in RSA mean time (p = 0.006) with only the RSG group showing an improvement after training (from 7.53 +/- 0.21 to 7.37 +/- 0.17 s). No other group x time interactions were found. Significant pre-post changes were found for absolute and relative maximum oxygen uptake and respiratory compensation point (p RSA training protocol used in this study can be an effective training strategy for inducing aerobic and football-specific training adaptations.

  17. High-precision measurements of cementless acetabular components using model-based RSA: an experimental study

    DEFF Research Database (Denmark)

    Baad-Hansen, Thomas; Kold, Søren; Kaptein, Bart L;

    2007-01-01

    BACKGROUND: In RSA, tantalum markers attached to metal-backed acetabular cups are often difficult to detect on stereo radiographs due to the high density of the metal shell. This results in occlusion of the prosthesis markers and may lead to inconclusive migration results. Within the last few yea...

  18. Model-based shape matching of orthopaedic implants in RSA and fluoroscopy

    NARCIS (Netherlands)

    Prins, Anne Hendrik

    2015-01-01

    Model-based shape matching is commonly used, for example to measure the migration of an implant with Roentgen stereophotogrammetric analysis (RSA) or to measure implant kinematics with fluoroscopy. The aim of this thesis was to investigate the general usability of shape matching and to improve the r

  19. A collection of insurance brands: The story of RSA in Ireland

    Directory of Open Access Journals (Sweden)

    Richard Brophy

    2015-12-01

    Full Text Available Many firms in financial services opt for corporate branding in order to unify their activities and leverage a strong brand across business units. While this may be the case, some financial service organisations retain the approach of using a collection of brands within the organisation. RSA has opted to retain its existing brands while gaining market share in Ireland. This paper studies the approach that RSA has taken in its brand architecture. Through a literature review of branding and rebranding, along with a historical study of the RSA Company going back to its foundation, the author attempts to chart the direction of the company alongside industry changes, such as product distribution and also the introduction of other stakeholders to the marketplace. Unlike its insurance peers, RSA is one of the few insurers that operates a portfolio of brands that operate in different markets within the industry. While the company is well known as a large insurer in Ireland, it retains its existing brands in a successful way through its product distribution

  20. 50 CFR 648.207 - Herring Research Set-Aside (RSA).

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Herring Research Set-Aside (RSA). 648.207... during the interim years and decides to publish a second RFP. Proposals to fund research that would start..., researchers must provide the Council and NMFS with a report of research findings, which must include:...

  1. HYBRID CHRIPTOGRAPHY STREAM CIPHER AND RSA ALGORITHM WITH DIGITAL SIGNATURE AS A KEY

    Directory of Open Access Journals (Sweden)

    Grace Lamudur Arta Sihombing

    2017-03-01

    Full Text Available Confidentiality of data is very important in communication. Many cyber crimes that exploit security holes for entry and manipulation. To ensure the security and confidentiality of the data, required a certain technique to encrypt data or information called cryptography. It is one of the components that can not be ignored in building security. And this research aimed to analyze the hybrid cryptography with symmetric key by using a stream cipher algorithm and asymmetric key by using RSA (Rivest Shamir Adleman algorithm. The advantages of hybrid cryptography is the speed in processing data using a symmetric algorithm and easy transfer of key using asymmetric algorithm. This can increase the speed of transaction processing data. Stream Cipher Algorithm using the image digital signature as a keys, that will be secured by the RSA algorithm. So, the key for encryption and decryption are different. Blum Blum Shub methods used to generate keys for the value p, q on the RSA algorithm. It will be very difficult for a cryptanalyst to break the key. Analysis of hybrid cryptography stream cipher and RSA algorithms with digital signatures as a key, indicates that the size of the encrypted file is equal to the size of the plaintext, not to be larger or smaller so that the time required for encryption and decryption process is relatively fast.

  2. Extending Algorithm of RSA Algorithm%基于RSA算法的扩展算法

    Institute of Scientific and Technical Information of China (English)

    张延招

    2011-01-01

    The security of RSA is designed on the basis of the difficulty of large integer decomposition.In the RSA public key encryption system the public key n is the product of two large prime number,aiming at the large integer n decomposition of the form n=pq(in which p,q as large prime number).The paper describes the encryption and decryption theory of extending RSA algorithm,aiming at the large integer n decomposition to the form n=p1,p2,…,pr(in which p1,p2,…,pr as large prime number).The addition of prime number could enhance the security of RSA algorithm.Compared to RSA algorithm,the extending RSA algorithm could be applied to both digital encryption/decryption and digital signature.Digital signature algorithm based on extending RSA algorithm is also of high security and reliability.%RSA的安全性是依据大整数分解的困难性而设计的。RSA公开密钥加密体制中n为2个大素数的乘积,即针对n=pq(p,q为大素数)的大整数分解,这里介绍了RSA算法的扩展算法的加密和解密原理,即针对n=p1,p2,…,pr(p1,p2,…,pr为大素数)的大整数分解。通过扩展素因子的个数达到RSA算法的安全性。比较RSA算法,扩展的RSA算法不仅可用于数据加密解密,也可用于数字签名。利用扩展的RSA算法实现数字签名也具有较高的安全性和可靠性。

  3. Repeated double-poling sprint training in hypoxia by competitive cross-country skiers.

    Science.gov (United States)

    Faiss, Raphael; Willis, Sarah; Born, Dennis-Peter; Sperlich, Billy; Vesin, Jean-Marc; Holmberg, Hans-Christer; Millet, Grégoire P

    2015-04-01

    Repeated-sprint training in hypoxia (RSH) was recently shown to improve repeated-sprint ability (RSA) in cycling. This phenomenon is likely to reflect fiber type-dependent, compensatory vasodilation, and therefore, our hypothesis was that RSH is even more beneficial for activities involving upper body muscles, such as double poling during cross-country skiing. In a double-blinded fashion, 17 competitive cross-country skiers performed six sessions of repeated sprints (each consisting of four sets of five 10-s sprints, with 20-s intervals of recovery) either in normoxia (RSN, 300 m; FiO2, 20.9%; n = 8) or normobaric hypoxia (RSH, 3000 m; FiO2, 13.8 %; n = 9). Before (pre) and after (post) training, performance was evaluated with an RSA test (10-s all-out sprints-20-s recovery, until peak power output declined by 30%) and a simulated team sprint (team sprint, 3 × 3-min all-out with 3-min rest) on a double-poling ergometer. Triceps brachii oxygenation was measured by near-infrared spectroscopy. From pretraining to posttraining, peak power output in the RSA was increased (P sprints performed was enhanced in RSH (10.9 ± 5.2 vs 17.1 ± 6.8, P sprints throughout RSA rose more in RSH (P sprints improved by 11% ± 9% in RSH and 15% ± 7% in RSN. Our findings reveal greater improvement in the performance of repeated double-poling sprints, together with larger variations in the perfusion of upper body muscles in RSH compared with those in RSN.

  4. Diurnal variations in physical performances related to football in young soccer players.

    Science.gov (United States)

    Chtourou, Hamdi; Hammouda, Omar; Souissi, Hichem; Chamari, Karim; Chaouachi, Anis; Souissi, Nizar

    2012-09-01

    This study investigated the effects of time-of-day on aerobic and anaerobic performances during the Yo-Yo, repeated sprint ability (RSA) and the Wingate tests in young soccer players. In a counterbalanced and a random order, twenty junior male soccer players completed the Yo-Yo, the RSA, and the Wingate tests at two different times-of-day: 07:00 and 17:00 h. During the Yo-Yo test, the total distance (TD) covered and the estimated maximal aerobic velocity (MAV) were determined. The peak power (PP) during each sprint, the percentage of decrement of PP (PD) and total work (Wtotal) during the RSA test were, also, measured. In addition, during the Wingate test, the peak (P(peak)) and mean (P(mean)) powers were recorded. During the Wingate test, P(peak) and P(mean) were significantly higher at 17:00 than 07:00 h (Pplayers.

  5. Algoritmo de criptografia RSA: análise entre a segurança e velocidade

    Directory of Open Access Journals (Sweden)

    Rafael Santos Andrade

    2012-12-01

    Full Text Available O objetivo deste trabalho é abordar a relação existente entre a busca pela segurança de dados e a velocidade de codificação e decodificação do algoritmo de criptografia RSA, que utiliza um par de números inteiros como ‘chave’. Considerando o tamanho da chave como requisito de segurança, devido à dificuldade computacional de fatorar números inteiros extensos, simulamos estes processos, com o algoritmo implementado na linguagem de programação C, utilizando chaves aleatórias de 1024, 2048 e 4096 bits. Desta forma, observamos o tempo de processamento em função do tamanho das chaves, confrontando segurança e desempenho.Palavras-chave: criptografia; algoritmo RSA; segurança; desempenho.

  6. Distributed Factorization Computation on Multiple Volunteered Mobile Resource to Break RSA Key

    Science.gov (United States)

    Jaya, I.; Hardi, S. M.; Tarigan, J. T.; Zamzami, E. M.; Sihombing, P.

    2017-01-01

    Similar to common asymmeric encryption, RSA can be cracked by usmg a series mathematical calculation. The private key used to decrypt the massage can be computed using the public key. However, finding the private key may require a massive amount of calculation. In this paper, we propose a method to perform a distributed computing to calculate RSA’s private key. The proposed method uses multiple volunteered mobile devices to contribute during the calculation process. Our objective is to demonstrate how the use of volunteered computing on mobile devices may be a feasible option to reduce the time required to break a weak RSA encryption and observe the behavior and running time of the application on mobile devices.

  7. RSA calibration accuracy of a fluoroscopy-based system using nonorthogonal images for measuring functional kinematics

    Energy Technology Data Exchange (ETDEWEB)

    Kedgley, Angela E.; Jenkyn, Thomas R. [Department of Mechanical and Materials Engineering, Faculty of Engineering, University of Western Ontario, London, Ontario N6A 5B9 (Canada); Wolf Orthopaedic Biomechanics Laboratory, Fowler Kennedy Sport Medicine Clinic, London, Ontario N6A 5B9 (Canada); Department of Mechanical and Materials Engineering, Faculty of Engineering, University of Western Ontario, London, Ontario N6A 5B9 (Canada) and School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, Ontario N6A 5B9 (Canada)

    2009-07-15

    When performing radiostereometric analysis (RSA) in a clinical setting it may be desirable to orient the two imaging devices nonorthogonally to obtain the best views of an anatomical structure. In this study, a calibration frame was constructed that allowed the relative angles of fiducial and control planes to be adjusted. Precision and accuracy were quantified across multiple trials and orientations. The 90 deg. frame was always of equivalent or greater accuracy than a calibration frame with the fiducial and control planes aligned parallel to the image intensifiers. This study also showed that RSA may be performed with imaging devices at relative angles other than 90 deg. without compromising accuracy. This allows researchers greater freedom in positioning equipment.

  8. Precision measurements of the RSA method using a phantom model of hip prosthesis.

    Science.gov (United States)

    Mäkinen, Tatu J; Koort, Jyri K; Mattila, Kimmo T; Aro, Hannu T

    2004-04-01

    Radiostereometric analysis (RSA) has become one of the recommended techniques for pre-market evaluation of new joint implant designs. In this study we evaluated the effect of repositioning of X-ray tubes and phantom model on the precision of the RSA method. In precision measurements, we utilized mean error of rigid body fitting (ME) values as an internal control for examinations. ME value characterizes relative motion among the markers within each rigid body and is conventionally used to detect loosening of a bone marker. Three experiments, each consisting of 10 double examinations, were performed. In the first experiment, the X-ray tubes and the phantom model were not repositioned between one double examination. In experiments two and three, the X-ray tubes were repositioned between one double examination. In addition, the position of the phantom model was changed in experiment three. Results showed that significant differences could be found in 2 of 12 comparisons when evaluating the translation and rotation of the prosthetic components. Repositioning procedures increased ME values mimicking deformation of rigid body segments. Thus, ME value seemed to be a more sensitive parameter than migration values in this study design. These results confirmed the importance of standardized radiographic technique and accurate patient positioning for RSA measurements. Standardization and calibration procedures should be performed with phantom models in order to avoid unnecessary radiation dose of the patients. The present model gives the means to establish and to follow the intra-laboratory precision of the RSA method. The model is easily applicable in any research unit and allows the comparison of the precision values in different laboratories of multi-center trials.

  9. Hybrid information privacy system: integration of chaotic neural network and RSA coding

    Science.gov (United States)

    Hsu, Ming-Kai; Willey, Jeff; Lee, Ting N.; Szu, Harold H.

    2005-03-01

    Electronic mails are adopted worldwide; most are easily hacked by hackers. In this paper, we purposed a free, fast and convenient hybrid privacy system to protect email communication. The privacy system is implemented by combining private security RSA algorithm with specific chaos neural network encryption process. The receiver can decrypt received email as long as it can reproduce the specified chaos neural network series, so called spatial-temporal keys. The chaotic typing and initial seed value of chaos neural network series, encrypted by the RSA algorithm, can reproduce spatial-temporal keys. The encrypted chaotic typing and initial seed value are hidden in watermark mixed nonlinearly with message media, wrapped with convolution error correction codes for wireless 3rd generation cellular phones. The message media can be an arbitrary image. The pattern noise has to be considered during transmission and it could affect/change the spatial-temporal keys. Since any change/modification on chaotic typing or initial seed value of chaos neural network series is not acceptable, the RSA codec system must be robust and fault-tolerant via wireless channel. The robust and fault-tolerant properties of chaos neural networks (CNN) were proved by a field theory of Associative Memory by Szu in 1997. The 1-D chaos generating nodes from the logistic map having arbitrarily negative slope a = p/q generating the N-shaped sigmoid was given first by Szu in 1992. In this paper, we simulated the robust and fault-tolerance properties of CNN under additive noise and pattern noise. We also implement a private version of RSA coding and chaos encryption process on messages.

  10. Observation of switching between SA and RSA in silver/goldpolyaniline nanocomposite films

    Science.gov (United States)

    Anand, P. B.; Jayalekshmi, S.

    2013-09-01

    In the present work, attempts have been made to embed Silver (Ag) /Gold (Au) - nanoparticles into polyaniline (PANI) matrix using an easy wet chemical route. It is expected that the resulting nanocomposite will show the interesting third order nonlinear optical characteristics of Ag/Au-nanoparicles modified by the advantageous properties of the conducting polymer PANI. Structural characterisation of Ag/Au-PANI nanocomposite samples was done using X-ray diffraction and Raman studies. UV-visible absorption spectra show the presence of surface plasmon resonance (SPR) peaks centred at 410 nm and 520 nm for Ag-PANI and Au-PANI nanocomposite films respectively, which is a signature of nano dimensionality of the composite samples. Third order nonlinear behaviour of the nanocomposite films was analysed using Z Scan technique employing the second harmonic output (532 nm) of a Q-switched Nd:YAG laser (Minilite, Continuum). It is seen that Ag/Au-PANI nanocomposite film samples show simultaneous presence of saturable absorption (SA) and reversible saturable absorptions (RSA) behaviour at 50 μJ laser excitation. This switching between SA and RSA has been reported in many metal nanocomposite systems. However similar behavior in nanocomposite film samples has not been pursued much. The highlight of the present work is the observation of the switching between SA and RSA in Ag/Au polyaniline nanocomposite films. The switching behavior can be ascribed to the interplay between ground state plasmon band bleaching and excited state absorption. Two photon assisted absorption has been identified as the prime factor contributing towards the observed RSA in these nanocomposite films.

  11. 'n Ondersoek na die amalgamering van skole in die RSA / André Johann Nel

    OpenAIRE

    Nel, André Johann

    1999-01-01

    Rationalisation, because of a lack of governmental funds, has become part of the education system of the RSA. In schools it implies that teaching posts are being reduced and that more emphasis is placed on the optimum use of physical facilities. For many smaller and rural schools, amalgamation became a possible solution to the problem. The amalgamation of schools however, implies a drastic change in the status quo. The main aim of the study is to investigate amalgamation as ...

  12. IMPLEMENTASI ALGORITMA KRIPTOGRAFI RIVEST SHAMIR ADLEMAN (RSA DAN VIGENERE CIPHER PADA GAMBAR BITMAP 8 BIT

    Directory of Open Access Journals (Sweden)

    Andro Alif Rakhman

    2015-07-01

    Full Text Available Penggunaan informasi melalui media gambar atau citra mempunyai beberapa kelemahan, salah satunya adalah kemudahan melakukan manipulasi citra oleh pihak-pihak tertentu dengan bantuan teknologi yang berkembang sekarang ini. Upaya dalam peningkatan pengamanan pengiriman informasi melalui media gambar dan perlindungan atas hak cipta hasil karya media digital maka algoritma kriptografi dapat diterapkan untuk pengamanan citra tersebut. Pada penelitian ini, menggunakan perpaduan algoritma Rivest Shamir Adleman (RSA dan Vigenere Cipher untuk melakukan pengamanan citra. Citra yang akan digunakan yaitu file bitmap dengan kedalaman piksel 8 bit. Citra akan diolah dengan cara mengenkripsi nilai indeks warna RGB pada masing-masing piksel dengan menggunakan algoritma kriptografi RSA terlebih dahulu kemudian dilanjutkan dengan menggunakan algoritma Vigenere Cipher. Sedangkan untuk tahap pendekripsiannya dilakukan dengan menggunakan algoritma Vigenere Cipher terlebuh dahulu kemudian menggunakan algoritma kriptografi RSA. Selanjutnya dilakukan analisis pengaruh penerapan algoritma Rivest Shamir Adleman (RSA dan Vigenere Cipher pada citra yang akan diamankan, meliputi analisis ruang kunci, analisis perubahan indeks warna, dan analisis waktu proses enkripsi dan deskripsi.Pengujian yang dilakukan untuk analisis tersebut, menggunakan citra berdimensi 3840 x 2160 piksel dan ukuran file 7,91 MB dan citra berdimensi 5012 x 2819 piksel dan ukuran file 13,4 MB. Analisis ruang kunci menunjukkan bahwa citra telah berhasil didekripsikan dan secara visual pola citra kembali ke bentuk semula tanpa mengalami cacat sedikitpun. Analisis perubahan indek warna, dilihat secara visual pada hasil palette warna membuktikan bahwa metode enkripsi yang dirancang telah berhasil digunakan untuk memperbaruhi nilai indeks warna citra asli. Sedangkan dari analisis waktu proses enkripsi dan deskripsi dapat disimpulkan Rata-rata lama waktu yang dibutuhkan untuk proses dekripsi lebih lama

  13. RSA加密算法中MPI的应用%Application of MPI in RSA encryption algorithm

    Institute of Scientific and Technical Information of China (English)

    陆玉阳

    2015-01-01

    RSA加密算法在进行复杂判断和大数运算时,计算时间往往花费较多,对计算机的运行速度、存储容量等方面具有较高的要求.MPI能够提供较快的数值计算和数据处理能力,提供高性能并行计算.该文通过在RSA加密算法中MPI的应用,通过实践证明MPI并行计算可以改进RSA算法,提高加密速度、减少容量需求等.%RSA encryption algorithm in the complex judgment and operation of large Nbers, calculating the time tend to spend more, the computer run faster, have higher requirements in terms of storage capacity. MPI provides fast Nerical calculation and data processing capability, providing high performance parallel computing. Based on RSA encryption algorithm in application of MPI, MPI parallel computing can improve the RSA algorithm proved by practice, increase speed, reduce capacity requirements, and so on.

  14. Aspects of ultra-high-precision diamond machining of RSA 443 optical aluminium

    Science.gov (United States)

    Mkoko, Z.; Abou-El-Hossein, K.

    2015-08-01

    Optical aluminium alloys such as 6061-T6 are traditionally used in ultra-high precision manufacturing for making optical mirrors for aerospace and other applications. However, the optics industry has recently witnessed the development of more advanced optical aluminium grades that are capable of addressing some of the issues encountered when turning with single-point natural monocrystalline diamond cutters. The advent of rapidly solidified aluminium (RSA) grades has generally opened up new possibilities for ultra-high precision manufacturing of optical components. In this study, experiments were conducted with single-point diamond cutters on rapidly solidified aluminium RSA 443 material. The objective of this study is to observe the effects of depth of cut and feed rate at a fixed rotational speed on the tool wear rate and resulting surface roughness of diamond turned specimens. This is done to gain further understanding of the rate of wear on the diamond cutters versus the surface texture generated on the RSA 443 material. The diamond machining experiments yielded machined surfaces which are less reflective but with consistent surface roughness values. Cutting tools were observed for wear through scanning microscopy; relatively low wear pattern was evident on the diamond tool edge. The highest tool wear were obtained at higher depth of cut and increased feed rate.

  15. Introducing random safety audits (RSA) in a neonatal intensive care unit (NICU).

    LENUS (Irish Health Repository)

    Szymanska, M

    2012-01-31

    Random safety audits (RSA) have been shown to be effective in improving standards of clinical practice. 19 data collection audits were performed relating to hygiene, safe prescribing, oxygen pulse oximetry monitoring and documentation in keeping with the requirements of the new Medical Practitioners Act (MPA) 2007. Hygiene audits (range from 20\\/25 to 21\\/21 80%-100%) and safe prescribing audits (range from 23\\/25 to 25\\/25 86%-100%) achieved n=25 100% compliance with unit guidelines over a 3 month period. Compliance with oxygen pulse oximetry monitoring guideline limits improved from 4\\/27 (15%) to 9\\/16 (56%). Compliance with requirement and use of Physician IMC registration number in documentation was only 10\\/18 (56%). RSA\\'s led to improvements in hygiene and prescribing. Compliance with oxygen monitoring guideline limits highlighted the need for greater education. Awareness of legal requirements relating to documentation improved but this has not translated into a change in practice. RSA\\'s can facilitate real time quality improvement in daily clinical practice.

  16. VLSI design of an RSA encryption/decryption chip using systolic array based architecture

    Science.gov (United States)

    Sun, Chi-Chia; Lin, Bor-Shing; Jan, Gene Eu; Lin, Jheng-Yi

    2016-09-01

    This article presents the VLSI design of a configurable RSA public key cryptosystem supporting the 512-bit, 1024-bit and 2048-bit based on Montgomery algorithm achieving comparable clock cycles of current relevant works but with smaller die size. We use binary method for the modular exponentiation and adopt Montgomery algorithm for the modular multiplication to simplify computational complexity, which, together with the systolic array concept for electric circuit designs effectively, lower the die size. The main architecture of the chip consists of four functional blocks, namely input/output modules, registers module, arithmetic module and control module. We applied the concept of systolic array to design the RSA encryption/decryption chip by using VHDL hardware language and verified using the TSMC/CIC 0.35 m 1P4 M technology. The die area of the 2048-bit RSA chip without the DFT is 3.9 × 3.9 mm2 (4.58 × 4.58 mm2 with DFT). Its average baud rate can reach 10.84 kbps under a 100 MHz clock.

  17. An RSA-Based Leakage-Resilient Authenticated Key Exchange Protocol Secure against Replacement Attacks, and Its Extensions

    Science.gov (United States)

    Shin, Seonghan; Kobara, Kazukuni; Imai, Hideki

    Secure channels can be realized by an authenticated key exchange (AKE) protocol that generates authenticated session keys between the involving parties. In [32], Shin et al., proposed a new kind of AKE (RSA-AKE) protocol whose goal is to provide high efficiency and security against leakage of stored secrets as much as possible. Let us consider more powerful attacks where an adversary completely controls the communications and the stored secrets (the latter is denoted by “replacement” attacks). In this paper, we first show that the RSA-AKE protocol [32] is no longer secure against such an adversary. The main contributions of this paper are as follows: (1) we propose an RSA-based leakage-resilient AKE (RSA-AKE2) protocol that is secure against active attacks as well as replacement attacks; (2) we prove that the RSA-AKE2 protocol is secure against replacement attacks based on the number theory results; (3) we show that it is provably secure in the random oracle model, by showing the reduction to the RSA one-wayness, under an extended model that covers active attacks and replacement attacks; (4) in terms of efficiency, the RSA-AKE2 protocol is comparable to [32] in the sense that the client needs to compute only one modular multiplication with pre-computation; and (5) we also discuss about extensions of the RSA-AKE2 protocol for several security properties (i.e., synchronization of stored secrets, privacy of client and solution to server compromise-impersonation attacks).

  18. The stress-inducible displacement detected through RSA in non-migrating UKR.

    Science.gov (United States)

    Bragonzoni, Laura; Russo, Alessandro; Loreti, Ivano; Montagna, Luisa; Visani, Andrea; Marcacci, Maurilio

    2005-08-01

    Roentgen stereophotogrammetric analysis (RSA) under stress conditions was used to investigate possible stress-inducible displacement of the tibial component of unicompartmental knee prostheses (UKR) in which the stability was previously assessed by radiographic evaluation and standard supine RSA examinations. Sixteen patients, implanted with Duracon UNI(R) prosthesis, were selected for this study. The RSA protocol included examinations in plain upright standing posture and during execution of stress-inducing tasks in weight-bearing stance. The first follow-up was performed at an average of 14 months, and the second one at 26 months. The results showed non-negligible stress-induced rotations of the prosthetic tibial component in all the patients in most of the stress tasks performed. Rotational stress tasks and squatting turned out to be the stress conditions in which induced displacement reached the most significant values (p<0.05). These micromotions occurred mainly around the transverse axis of the knee joint and in one examination around the sagittal axis. Stress-induced translations were negligible in all the examinations. Moreover, we focused our attention on two patients suffering from inexplicable pain, and we observed a significant difference in the inducible rotation around the x-axis between these patients and the remaining fourteen. Stress-inducible displacement is a common finding in knee prostheses, but we observed that in patients with inexplicable pain, these micromotions reached values greater than the median calculated on patients without any pain. This result suggests the introduction of the stress-inducible displacement as a new parameter to be taken into consideration when analyzing the outcome of patients treated by UKR.

  19. 基于Common Lisp的RSA加密实现%RSA Encryption Based on Common Lisp Implementation

    Institute of Scientific and Technical Information of China (English)

    解晨

    2013-01-01

    著名的非对称密钥加密系统——RSA公钥加密系统,是当今流行的加密系统,其简单的实现和高效的保密性使RSA加密算法成为当下最有影响力的公钥加密算法,并且其堪称完美的理论基础使得RSA加密算法可以抵抗目前所知的所有密码攻击.该文探究了RSA加密算法的原理,并使用一门小众语言Common Lisp对RSA加密进行了实现.%Asymmetric key encryption system -- the famous RSA public key encryption system, the encryption system is popu?lar, its simple implementation and high security RSA encryption algorithm to become the most influential contemporary public-key encryption algorithm, and it is theoretical basis of perfect makes the RSA encryption algorithm can resist all known attacks. This paper discusses the principle of RSA encryption algorithm, and realizes the encryption of RSA using a minority language Common Lisp.

  20. Non-random association of the Rsa I polymorphic site 5' to the beta-globin gene with major sickle cell haplotypes.

    Science.gov (United States)

    Sharon, B; Poncz, M; Surrey, S; Schwartz, E

    1988-01-01

    There are three main African haplotypes associated with the sickle mutation on chromosome 11. We have examined an Rsa I polymorphism 550 bp 5' to the beta-globin gene to study the degree of linkage disequilibrium between this Rsa I site and the three haplotypes. This Rsa I site is contained within the 10.3 kb or less area of randomization separating the 5'- and 3'-haplotype clusters. The beta S-containing chromosomes of the Benin and Senegal haplotypes are not cut, while those of the Central African Republic are cleaved by Rsa I at this site. Possible explanations of these findings are discussed.

  1. Improved RSA cryptosystem based on the study of number theory and public key cryptosystems

    Directory of Open Access Journals (Sweden)

    Israt Jahan

    2015-01-01

    Full Text Available Security is required to transmit confidential information over the network. Security is also demanding in wide range of applications. Cryptographic algorithms play a vital role in providing the data security against malicious attacks. RSA algorithm is extensively used in the popular implementations of Public Key Infrastructures. In asymmetric key cryptography, also called Public Key cryptography, two different keys (which form a key pair are used. One key is used for encryption and only the other corresponding key must be used for decryption. No other key can decrypt the message – not even the original (i.e. the first key used for encryption. In this paper, we have proposed an improved approach of RSA algorithm using two public key pairs and using some mathematical logic rather than sending one public key d irectly.Because if an attacker has an opportunity of getting the public key componet they can find private key value by brute force search. General Terms: Cryptography, network security

  2. Fibrinogen adsorption mechanisms at the gold substrate revealed by QCM-D measurements and RSA modeling.

    Science.gov (United States)

    Kubiak, Katarzyna; Adamczyk, Zbigniew; Cieśla, Michał

    2016-03-01

    Adsorption kinetics of fibrinogen at a gold substrate at various pHs was thoroughly studied using the QCM-D method. The experimental were interpreted in terms of theoretical calculations performed according to the random sequential adsorption model (RSA). In this way, the hydration functions and water factors of fibrinogen monolayers were quantitatively evaluated at various pHs. It was revealed that for the lower range of fibrinogen coverage the hydration function were considerably lower than previously obtained for the silica sensor [33]. The lower hydration of fibrinogen monolayers on the gold sensor was attributed to its higher roughness. However, for higher fibrinogen coverage the hydration functions for both sensors became identical exhibiting an universal behavior. By using the hydration functions, the fibrinogen adsorption/desorption runs derived from QCM-D measurements were converted to the Γd vs. the time relationships. This allowed to precisely determine the maximum coverage that varied between 1.6mgm(-2) at pH 3.5 and 4.5mgm(-2) at pH 7.4 (for ionic strength of 0.15M). These results agree with theoretical eRSA modeling and previous experimental data derived by using ellipsometry, OWLS and TIRF. Various fibrinogen adsorption mechanisms were revealed by exploiting the maximum coverage data. These results allow one to develop a method for preparing fibrinogen monolayers of well-controlled coverage and molecule orientation. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Cryptanalysis and Performance Evaluation of Enhanced Threshold Proxy Signature Scheme Based on RSA for Known Signers

    Directory of Open Access Journals (Sweden)

    Raman Kumar

    2013-01-01

    Full Text Available In these days there are plenty of signature schemes such as the threshold proxy signature scheme (Kumar and Verma 2010. The network is a shared medium so that the weakness security attacks such as eavesdropping, replay attack, and modification attack. Thus, we have to establish a common key for encrypting/decrypting our communications over an insecure network. In this scheme, a threshold proxy signature scheme based on RSA, any or more proxy signers can cooperatively generate a proxy signature while or fewer of them cannot do it. The threshold proxy signature scheme uses the RSA cryptosystem to generate the private and the public key of the signers (Rivest et al., 1978. Comparison is done on the basis of time complexity, space complexity, and communication overhead. We compare the performance of four schemes (Hwang et al. (2003, Kuo and Chen (2005, Yong-Jun et al. (2007, and Li et al. (2007, with the performance of a scheme that has been proposed earlier by the authors of this paper. In the proposed scheme, both the combiner and the secret share holder can verify the correctness of the information that they are receiving from each other. Therefore, the enhanced threshold proxy signature scheme is secure and efficient against notorious conspiracy attacks.

  4. Algebra Structure of RSA Arithmetic%RSA算法中的代数结构

    Institute of Scientific and Technical Information of China (English)

    司光东; 杨加喜; 谭示崇; 肖国镇

    2011-01-01

    本文首次应用二次剩余理论对RSA中的代数结构进行了研究.计算出了Zn中模n的二次剩余和二次非剩余的个数,对它们之间的关系进行了分析,并用所有二次剩余构成的群对Zn进行了分割,证明了所有陪集构成的商群是一个Klein四元群.对强RSA的结构进行了研究,证明了强RSA中存在阶为φ(n)/2的元素,并且强RSA中Zn可由三个二次非剩余的元素生成.确定了Zn中任意元素的阶,证明了Zn中所有元素阶的最大值是lcm(p-1,q-1),并且给出了如何寻找Zn中最大阶元素方法.从而解决了RSA中的代数结构.%Based on the theory of quadratic residues, the algebra structure of RSA arithmetic is researched in this paper. This work calculates numbers of quadratic residues and non-residues in the group Zn* and investigates their relationship. Z*n is divided up by the group made up with all quadratic residues in Z*n and all cosets form a quotient group of order 4 which is a Klein group.Studyed the structure of strong RSA further,it shows that the element of order φ( n)/2 exists and the group Z*n can be generated by three elements of quadratic non-residues. Let the facterization n = p · q, the order of each element can be calculated, and the biggest order of all element is lcn ( p - 1, q - 1 ) in Z*n. It also shows how to find the element of the biggest order. So the algebra structure of RSA arithmetic is solved.

  5. Improvisation of Security aspect of Steganographic System by applying RSA Algorithm

    Directory of Open Access Journals (Sweden)

    Manoj Kumar Ramaiya

    2016-07-01

    Full Text Available The applications accessing multimedia systems and content over the internet have grown extremely in the earlier few years. Moreover, several end users or intruders can simply use tools to synthesize and modify valuable information. The safety of information over unsafe communication channel has constantly been a primary concern in the consideration of researchers. It became one of the most important problems for information technology and essential to safeguard this valuable information during transmission. It is also important to determine where and how such a multimedia file is confidential. Thus, a need exists for emerging technology that helps to defend the integrity of information and protected the intellectual property privileges of owners. Various approaches are coming up to safeguard the data from unauthorized person. Steganography and Cryptography are two different techniques for security data over communication network. The primary purpose of Cryptography is to create message concept unintelligible or ciphertext might produce suspicious in the mind of opponents. On the other hand, Steganography implant secrete message in to a cover media and hides its existence. As a normal practice, data embedding is employed in communication, image, text or multimedia contents for the purpose of copyright, authentication and digital signature etc. Both techniques provides the sufficient degree of security but are vulnerable to intruder’s attacks when used over unsecure communication channel. Attempt to combines the two techniques i.e. Cryptography and Steganography, did results in security improvement. The existing steganographic algorithms primarily focus on embedding approach with less attention to pre-processing of data which offer flexibility, robustness and high security level. Our proposed model is based on Public key cryptosystem or RSA algorithms in which RSA algorithm is used for message encryption in encoding function and the resultant

  6. Association between estrogen receptor β gene Rsa1 polymorphism and depressive disorder in peri-menopausal and menopausal women

    Institute of Scientific and Technical Information of China (English)

    YU Xue-wen; REN Yong-hui; LI Xue-cheng; GAO Cheng-ge; LI Fen; HAN Zhen; LI Xu

    2005-01-01

    Objective: To investigate estrogen receptor β (ERβ) gene Rsa1 polymorphism and concentration of estrogen, FSH and LH in serum in peri-menopausal and menopausal women with depressive disorder. Methods: Seventy-four peri-menopausal and menopausal women with depressive disorder met ICD-10 and CCMD-3 assessment criteria for depressive disorder were recruited. ERβ gene Rsa1 polymorphism was analyzed with PCR-RFLP. Serum levels of estrogen, FSH and LH were measured by magnetism-ELISA. Results: The respective frequency of ERβ gene Rsa1 polymorphism was no significant difference between women with depressive disorder and the healthy women (χ2=1.106,P>0.05). The serum level of estrogen was lower in women with depressive disorder than in the healthy women (P<0.05). No difference was found for FSH and LH between two groups. Conclusion: ERβ gene Rsa1 polymorphism may be not associated with depressive disorder in the peri-menopausal and menopausal women. The serum level of estrogen is associated with depressive disorder in the peri-menopausal and menopausal women.

  7. Three Year RSA Evaluation of Vitamin E Diffused Highly Cross-linked Polyethylene Liners and Cup Stability

    DEFF Research Database (Denmark)

    Sillesen, Nanna H; Greene, Meridith E; Nebergall, Audrey K;

    2015-01-01

    Vitamin E diffusion into highly cross-linked polyethylene (E-XLPE) is a method for enhancing oxidative stability of acetabular liners. The purpose of this study was to evaluate in vivo penetration of E-XLPE using radiostereometric analysis (RSA). Eighty-four hips were recruited into a prospective...

  8. Crystal structure of Pseudomonas aeruginosa RsaL bound to promoter DNA reaffirms its role as a global regulator involved in quorum-sensing

    Science.gov (United States)

    Kang, Huaping; Gan, Jianhua; Zhao, Jingru; Kong, Weina; Zhang, Jing; zhu, Miao; Li, Fan; Song, Yaqin; Qin, Jin; Liang, Haihua

    2017-01-01

    Pseudomonas aeruginosa possesses at least three well-defined quorum-sensing (QS) (las, rhl and pqs) systems that control a variety of important functions including virulence. RsaL is a QS repressor that reduces QS signal production and ensures homeostasis by functioning in opposition to LasR. However, its regulatory role in signal homeostasis remains elusive. Here, we conducted a ChIP-seq assay and revealed that RsaL bound to two new targets, the intergenic regions of PA2228/PA2229 and pqsH/cdpR, which are required for PQS synthesis. Deletion of rsaL reduced transcription of pqsH and cdpR, thus decreasing PQS signal production. The ΔrsaL strain exhibited increased pyocyanin production and reduced biofilm formation, which are dependent on CdpR or PqsH activity. In addition, we solved the structure of the RsaL–DNA complex at a 2.4 Å resolution. Although the overall sequence similarity is quite low, RsaL folds into a HTH-like structure, which is conserved among many transcriptional regulators. Complementation results of the rsaL knockout cells with different rsaL mutants further confirmed the critical role of the DNA-binding residues (including Arg20, Gln27, Gln38, Gly35, Ser37 and Ser42) that are essential for DNA binding. Our findings reveal new targets of RsaL and provide insight into the detailed characterization of the RsaL–DNA interaction. PMID:27924027

  9. Iron status markers are only transiently affected by a football game.

    Science.gov (United States)

    Jamurtas, Athanasios Z; Douroudos, Ioannis I; Deli, Chariklia K; Draganidis, Dimitrios; Chatzinikolaou, Athanasios; Mohr, Magni; Avloniti, Alexandra; Barbero-Álvarez, Jose C; Margonis, Konstantinos; Mavropalias, Georgios; Stampoulis, Theodoros; Giannakidou, Dimitra; Flouris, Andreas D; Koutedakis, Yannis; Fatouros, Ioannis G

    2015-01-01

    We examined the temporal variation of iron's status markers during a 60 h period following a football game. Thirty-four male football players were randomly assigned to a control group (CG, N = 14, participated only in measurements and training) or an experimental group (EG, N = 20, took part in a football game one week after the completion of the competitive season). All participants trained regularly for two consecutive days after the game. Training and game load was monitored with high time-resolution global positioning system (GPS) devices. Blood samples were collected and muscle damage markers and repeated sprint ability (RSA) were assessed pre-game and at 2 h, 12 h 36 h and 60 h post-game. No changes were noted in CG. Iron concentration decreased (P RSA declined (P football game.

  10. 对RSA密码系统旁路攻击的防御%Resistance against side channel attack for RSA cryptosystem

    Institute of Scientific and Technical Information of China (English)

    祝力; 谷大武; 王超

    2008-01-01

    Based on the structure of the side channel attacks (SCAs) to RSA cryptosystem can resist the fault attack andcombine with the randomization method for the message and secret exponent, a new implementation scheme of CRT-based(the Chinese remained theorem) RSA is proposed. The proposed scheme can prevent simple power analysis (SPA), differentialpower analysis (DPA) and time attack, and is compatible with the existing RSA-CRT cryptosystem as well. In addition, animprovement for resisting fault attack is proposed, which can reduce extra computation time.

  11. Information security in data exchange between mobile devices with Android system using RSA encryption

    Directory of Open Access Journals (Sweden)

    Fernando Solís

    2017-02-01

    Full Text Available The new styles and ways of life lead to greater use of wireless networks, the mobile device being a tool for data transmission, which are susceptible to threats in the transmission channels in the network. IT security plays a very important role in guaranteeing the availability, privacy and integrity of information, one of the techniques that helps in this task is cryptography, whose foundation is to transform a message so that it is unintelligible except for those who have the Key to decipher it. The research focuses on the use of the RSA algorithm between mobile devices, the encrypted data is sent through communication channels called threads that through formulas and processes executed on the server, will help to execute the encryption and decryption of the data. To carry it out, a prototype for the exchange of data between mobile devices wirelessly was designed and implemented, conducting performance tests with three nodes to improve the security. The results show the efficiency of the algorithm and additionally its functionality, the times of encryption and decryption are fast against the sending of information without any method or algorithm used.

  12. DMAC-AN INTEGRATED ENCRYPTION SCHEME WITH RSA FOR AC TO OBSTRUCT INFERENCE ATTACKS

    Directory of Open Access Journals (Sweden)

    R. Jeeva

    2012-12-01

    Full Text Available The proposal of indistinguishable encryption in Randomized Arithmetic Coding(RAC doesn’t make the system efficient because it was not encrypting the messages it sends. It recomputes the cipher form of every messages it sends that increases not only the computational cost but also increases the response time.Floating point representation in cipher increases the difficulty in decryption side because of loss in precison.RAC doesn’t handle the inference attacks like Man-in-Middle attack,Third party attack etc. In our system, Dynamic Matrix Arithmetic Coding(DMAC using dynamic session matrix to encrypt the messages. The size of the matrix is deduced from the session key that contains ID of end users which proves the server authentication.Nonce values is represented as the public key of the opponents encrypted by the session key will be exchanged between the end users to provide mutual authentication. If the adversary try to compromise either server or end users,the other system won’t respond and the intrusion will be easily detected. we have increased the hacking complexity of AC by integrating with RSA upto 99%.

  13. Die godsdiensneutraliteitsbeginsel van die Amerikaanse demokrasie - implikasie vir onderwys in die RSA

    Directory of Open Access Journals (Sweden)

    J.G. van Staden

    1995-03-01

    Full Text Available The principle of religious neutrality in the American democracy - implications for education in the RSA In a changing, democratic educational dispensation the accommodation of various religious convictions and religious needs of the heterogenous South African population is a matter that has to be dealt with with great circumspection. Valuable lessons that can prevent distress and disruption may be learnt from the way in which the American hyper-democracy has handled the situation. Democracy is the American's predominant pre-occupation. Any attempt of any group (e.g. a religious group to grant a monopoly in state schools to religious values in special learning content and religious ceremonies and practices has always been opposed. This approach has eventually led to total neutrality as regards traditional religious convictions and practices in American state schools, resulting in the establishment of another conviction (secular humanism in state schools. Thus it seems that neutrality as regards religious convictions is not possible. Absolutism of the principle of neutrality as regards traditional religions has resulted in a degeneration of moral values. If all the religious convictions cannot be accommodated in the South African public education system, it may for South Africa, as bastion of Christian civilization, be a danger sign as has been the case in the USA.

  14. Three Year RSA Evaluation of Vitamin E Diffused Highly Cross-linked Polyethylene Liners and Cup Stability.

    Science.gov (United States)

    Sillesen, Nanna H; Greene, Meridith E; Nebergall, Audrey K; Nielsen, Poul T; Laursen, Mogens B; Troelsen, Anders; Malchau, Henrik

    2015-07-01

    Vitamin E diffusion into highly cross-linked polyethylene (E-XLPE) is a method for enhancing oxidative stability of acetabular liners. The purpose of this study was to evaluate in vivo penetration of E-XLPE using radiostereometric analysis (RSA). Eighty-four hips were recruited into a prospective 10-year RSA. This is the first evaluation of the multicenter cohort after 3-years. All patients received E-XLPE liners (E1, Biomet) and porous-titanium coated cups (Regenerex, Biomet). There was no difference (P=0.450) in median femoral head penetration into the E-XLPE liners at 3-years comparing cobalt-chrome heads (-0.028mm; inter-quartile range (IQR) - 0.065 to 0.047) with ceramic heads (-0.043mm, IQR - 0.143to0.042). The 3-year follow-up indicates minimal E-XLPE liner penetration regardless of head material and minimal early cup movement.

  15. The robustness and accuracy of in vivo linear wear measurements for knee prostheses based on model-based RSA.

    Science.gov (United States)

    van Ijsseldijk, E A; Valstar, E R; Stoel, B C; Nelissen, R G H H; Reiber, J H C; Kaptein, B L

    2011-10-13

    Accurate in vivo measurements methods of wear in total knee arthroplasty are required for a timely detection of excessive wear and to assess new implant designs. Component separation measurements based on model-based Roentgen stereophotogrammetric analysis (RSA), in which 3-dimensional reconstruction methods are used, have shown promising results, yet the robustness of these measurements is unknown. In this study, the accuracy and robustness of this measurement for clinical usage was assessed. The validation experiments were conducted in an RSA setup with a phantom setup of a knee in a vertical orientation. 72 RSA images were created using different variables for knee orientations, two prosthesis types (fixed-bearing Duracon knee and fixed-bearing Triathlon knee) and accuracies of the reconstruction models. The measurement error was determined for absolute and relative measurements and the effect of knee positioning and true seperation distance was determined. The measurement method overestimated the separation distance with 0.1mm on average. The precision of the method was 0.10mm (2*SD) for the Duracon prosthesis and 0.20mm for the Triathlon prosthesis. A slight difference in error was found between the measurements with 0° and 10° anterior tilt. (difference=0.08mm, p=0.04). The accuracy of 0.1mm and precision of 0.2mm can be achieved for linear wear measurements based on model-based RSA, which is more than adequate for clinical applications. The measurement is robust in clinical settings. Although anterior tilt seems to influence the measurement, the size of this influence is low and clinically irrelevant.

  16. Validation of a low-dose hybrid RSA and fluoroscopy technique: Determination of accuracy, bias and precision.

    Science.gov (United States)

    Ioppolo, James; Börlin, Niclas; Bragdon, Charles; Li, Mingguo; Price, Roger; Wood, David; Malchau, Henrik; Nivbrant, Bo

    2007-01-01

    Analyzing skeletal kinematics with radiostereometric analysis (RSA) following corrective orthopedic surgery allows the quantitative comparison of different implant designs. The purpose of this study was to validate a technique for dynamically estimating the relative position and orientation of skeletal segments using RSA and single plane X-ray fluoroscopy. Two micrometer-based in vitro phantom models of the skeletal segments in the hip and knee joints were used. The spatial positions of tantalum markers that were implanted into each skeletal segment were reconstructed using RSA. The position and orientation of each segment were determined in fluoroscopy images by minimizing the difference between the markers measured and projected in the image plane. Accuracy was determined in terms of bias and precision by analyzing the deviation between the applied displacement protocol and measured pose estimates. Measured translational accuracy was less than 100 microm parallel to the image plane and less than 700 microm in the direction orthogonal to the image plane. The measured rotational error was less than 1 degrees . Measured translational and rotational bias was not statistically significant at the 95% level of confidence. The technique allows real-time kinematic skeletal measurements to be performed on human subjects implanted with tantalum markers for quantitatively measuring the motion of normal joints and different implant designs.

  17. Implementation of Digital Signature Using Aes and Rsa Algorithms as a Security in Disposition System af Letter

    Science.gov (United States)

    Siregar, H.; Junaeti, E.; Hayatno, T.

    2017-03-01

    Activities correspondence is often used by agencies or companies, so that institutions or companies set up a special division to handle issues related to the letter management. Most of the distribution of letters using electronic media, then the letter should be kept confidential in order to avoid things that are not desirable. Techniques that can be done to meet the security aspect is by using cryptography or by giving a digital signature. The addition of asymmetric and symmetric algorithms, i.e. RSA and AES algorithms, on the digital signature had been done in this study to maintain data security. The RSA algorithm was used during the process of giving digital signature, while the AES algorithm was used during the process of encoding a message that will be sent to the receiver. Based on the research can be concluded that the additions of AES and RSA algorithms on the digital signature meet four objectives of cryptography: Secrecy, Data Integrity, Authentication and Non-repudiation.

  18. The Effect of Ramadan Fasting on Physical Performances, Mood State and Perceived Exertion in Young Footballers

    Science.gov (United States)

    Chtourou, Hamdi; Hammouda, Omar; Souissi, Hichem; Chamari, Karim; Chaouachi, Anis; Souissi, Nizar

    2011-01-01

    Purpose This study was designed to assess the effects of Ramadan fasting on the profile of mood state and perceived exertion in young soccer players and aerobic and anaerobic performances during the Yo-Yo, repeated sprint ability (RSA) and the Wingate tests. Methods Twenty junior male soccer players completed the Yo-Yo, the RSA, and the Wingate tests on three different occasions: one-week before Ramadan (BR), the second week (SWR) and the fourth week (ER) of Ramadan. The total distance (TD) covered and the estimated maximal aerobic velocity (MAV) during the Yo-Yo test were recorded. During the RSA test, peak power (PP) during each sprint, the percentage of decrement of PP (PD) and total work (Wtotal) were calculated. During the Wingate test, peak (Ppeak) and mean (Pmean) powers and fatigue index (FI) were recorded. Results TD and MAV (P=0.01) during the Yo-Yo test and PP (P=0.01, P=0.004, P=0.001, P=0.01, P=0.03 for sprints 1, 2, 3, 4, and 5, respectively) and Wtotal (P=0.02) during the RSA test were significantly higher during BR than ER. Furthermore, muscle fatigue during the RSA test increased significantly from BR to ER (P=0.01). Ppeak and Pmean during the Wingate test decreased significantly from BR to SWR and ER (PRSA and the Wingate tests were affected by Ramadan fasting in young soccer players. PMID:22375237

  19. Repeated Dribbling Ability in Young Soccer Players: Reproducibility and Variation by the Competitive Level

    Directory of Open Access Journals (Sweden)

    Duarte João P.

    2016-12-01

    Full Text Available The intermittent nature of match performance in youth soccer supports relevance of ability to repeatedly produce high-intensity actions with short recovery periods. This study was aimed to examine the reproducibility of a repeated dribbling ability protocol and, additionally, to estimate the contribution of concurrent tests to explain inter-individual variability in repeated dribbling output. The total sample comprised 98 players who were assessed as two independent samples: 31 players were assessed twice to examine reliability of the protocol; and 67 juveniles aged 16.1 ± 0.6 years were compared by the competitive level (local, n = 34; national, n = 33 to examine construct validity. All single measurements appeared to be reasonably reliable: total (ICC = 0.924; 95%CI: 0.841 to 0.963; ideal (ICC = 0.913; 95%CI: 0.820 to 0.958; worst (ICC = 0.813; 95%CI: 0.611 to 0.910. In addition, the percentage of the coefficient of variation was below the critical value of 5% for total (%CV = 3.84; TEM = 2.51 s; ideal (%CV = 3.90, TEM = 2.48 s. Comparisons between local and national players suggested magnitude effects as follows: moderate (d-value ranged from 0.63 to 0.89 for all repeated sprint ability scores; large for total (d = 1.87, ideal (d = 1.72, worst (d = 1.28 and moderate for composite scores: the fatigue index (d = 0.69 and the decrement score (d = 0.67. In summary, the dribbling protocol presented reasonable reproducibility properties and output extracted from the protocol seemed to be independent from biological maturation.

  20. Measured In Situ Atmospheric Ambient Aerosol Size-Distributions, Particle Concentrations, and Turbulence Data for RSA TA-6 Test Range, Redstone Arsenal, AL, April-May 2015

    Science.gov (United States)

    2015-09-01

    Concentrations, and Turbulence Data for RSA TA-6 Test Range, Redstone Arsenal , AL, April–May 2015 by Kristan Gurton, Stephanie Cunningham, and...Aerosol Size-Distributions, Particle Concentrations, and Turbulence Data for RSA TA-6 Test Range, Redstone Arsenal , AL, April–May 2015 by Kristan...Redstone Arsenal , AL Approved for public release; distribution unlimited. ii REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188

  1. CUDA based high performance implementation of RSA algorithm.%RSA算法的CUDA高效实现技术

    Institute of Scientific and Technical Information of China (English)

    孙迎红; 童元满; 王志英

    2011-01-01

    As a new architecture supporting general purpose computing on GPU, Compute Unified Device Architecture(CUDA) plays an important role in massive data parallel computing. RSA is a kind of computing concentrated public key cryptographic algorithm. To improve the performance of RSA algorithm,CUDA based high performance implementation is presented in this paper. The key of CUDA implementation of RSA is large amount of independent parallel Montgomery modular multiplication thread in the kernel side. The threads organization scheme and data structure of this implementation are also presented. Besides, shared memory based performance improvement method is also presented. According to the implementation method of this paper, the performance and throughput of RSA algorithm are obtained for a CUDA GPU.The experiment results show that the CUDA implementation can achieve more than 40 times speedup in comparison with general CPU implementation of RSA.%CUDA(Compute Unified Device Architecture)作为一种支持GPU通用计算的新型计算架构,在大规模数据并行计算方面得到了广泛的应用.RSA算法是一种计算密集型的公钥密码算法,给出了基于CUDA的RSA算法并行化高效实现技术,其关键为引入大量独立并发的Montgomery模乘线程,并给出了具体的线程组织、数据存储结构以及基于共享内存的性能优化实现技术.根据RSA算法CUDA实现方法,在某款GPU上测试了RSA算法的运算性能和吞吐率.实验结果表明,与RSA算法的通用CPU实现方式相比,CUDA实现能够实现超过40倍的性能加速.

  2. CYP2E1 Rsa Ⅰ polymorphism impacts on risk of colorectal cancer association with smoking and alcohol drinking

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    AIM: To investigate associations between the Rsa Ⅰpolymorphism of CYP2E1 and risk of colorectal cancer.METHODS: A case-control study was conducted with 315 colorectal cancer cases (105 colon, 210 rectal)and 439 population-based controls in Jiangsu Province of China. Genomic DNA samples were assayed for restriction fragment length polymorphisms in CYP2E1by PCR amplification followed by digestion with Rsa Ⅰ. Information on smoking and alcohol drinking was collected using a questionnaire. Odds ratios (ORs) were estimated with an unconditional logistic model.RESULTS: The proportional distribution of the CYP2E1 Rsa Ⅰ c1/c1, c1/c2 and c2/c2 genotypes were 61.4%,35.6% and 3.0% in controls, 60.6%, 33.7% and 5.8%in colon cancer cases, and 58.4%, 34.0% and 7.7% in rectal cancer cases, respectively. A significant difference was noted between controls and rectal cancer cases (P = 0.029), the c2/c2 genotype being associated with elevated OR (adjusted age, sex and status of the smoking and alcohol drinking) for rectal cancer (1.64,95% CI, 1.12-2.41, vs c1 allele carriers), but not for colon cancer. In interaction analysis between the CYP2E1Rsa Ⅰ genotype and smoking and drinking habits, we found a significant cooperative action between the c2/c2 genotype and alcohol drinking in the sex-, age-adjusted ORs for both colon (4.74, 95% CI, 1.10-20.40) and rectal (5.75, 95% CI, 1.65-20.05) cancers. Among nonsmokers, the CYP2E1 Rsa Ⅰ c2/c2 genotype was also associated with elevated ORs in the two sites (1.95, 95%CI, 0.99-3.86 and 2.30, 95% CI, 1.32-3.99).CONCLUSION: The results of the present study suggest that the CYP2E1 c2/c2 genotype increases susceptibility to rectal cancer and the gene-environmental interactions between the CYP2E1 polymorphism and smoking or alcohol drinking exist for colorectal neoplasia in general.

  3. Effects of seated and standing cold water immersion on recovery from repeated sprinting.

    Science.gov (United States)

    Leeder, Jonathan D C; van Someren, Ken A; Bell, Phillip G; Spence, John R; Jewell, Andrew P; Gaze, David; Howatson, Glyn

    2015-01-01

    This study investigated the effects of two different hydrostatic pressures (seated or standing) during cold water immersion at attenuating the deleterious effects of strenuous exercise on indices of damage and recovery. Twenty four male well-trained games players (age 23 ± 3 years; body mass 81.4 ± 8.7 kg: [Formula: see text]O2max 57.5 ± 4.9 ml∙kg(-1)∙min(-1)) completed the Loughborough Intermittent Shuttle Test (LIST) and were randomly assigned to either a control, seated cold water immersion or a standing cold water immersion (14 min at 14°C). Maximal isometric voluntary contraction, counter-movement jump, creatine kinase, C-reactive protein, interleukin-6 and delayed onset muscle soreness (DOMS) were measured before and up to 72 h following the LIST. All dependent variables showed main effects for time (P cold water immersion interventions. Seated cold water immersion was associated with lower DOMS than standing cold water immersion (effect size = 1.86; P = 0.001). These data suggest that increasing hydrostatic pressure by standing in cold water does not provide an additional recovery benefit over seated cold water immersion, and that both seated and standing immersions have no benefit in promoting recovery following intermittent sprint exercise.

  4. Emotional responses during repeated sprint intervals performed on level, downhill and uphill surfaces.

    Science.gov (United States)

    Baron, Bertrand; Guilloux, Bertrand; Begue, Mylène; Uriac, Stéphane

    2015-01-01

    The purpose of this study was to test emotional responses during sprint intervals performed on a level, down and up surface. Fifty trained participants performed a maximal effort during a 60-m sprint and 10 repetitions of 60 m running sprints on a level, down and up surface on a 5.9% slope. Running speeds, emotional responses and heart rate were measured. Self-selected speeds were correlated with the rating of perceived exertion, the affective balance, the desire to stop and the resources needed for the task in all conditions whereas the pleasure, the desire to continue and the capacity to realise the task were correlated with speeds only during level and uphill running. Mean values of emotional parameters were significantly different (P < 0.05) during running on a flat surface, downhill and uphill. When the gradient of running surface is changed, the pattern of emotional responses was just translated, i.e. most of the slope between the evolution of emotional parameters and the repetitions were not significantly different whereas Y-intercepts were different. Consented effort is highly correlated with the resources needed for the task (P < 0.001, r(2) = 0.72). We propose that the difference in the resources needed for the task between level, downhill and uphill running (F 2, 1499 = 166.5, P < 0.001, Eta(2) = 0.18) is the most important key that explains our results.

  5. URINARY CREATINE AT REST AND AFTER REPEATED SPRINTS IN ATHLETES: A PILOT STUDY

    Directory of Open Access Journals (Sweden)

    I. Bezrati-Benayed

    2014-07-01

    Full Text Available Creatine plays a key role in muscle function and its evaluation is important in athletes. In this study, urinary creatine concentration was measured in order to highlight its possible significance in monitoring sprinters. The study included 51 sprinters and 25 age- and sex-matched untrained subjects as a control group. Body composition was measured and dietary intake estimated. Urine samples were collected before and after standardized physical exercise. Creatine was assessed by gas chromatography mass spectrometry. Basal urinary creatine (UC was significantly lower in sprinters than controls (34±30 vs. 74±3 μmol/mmol creatinine, p<0.05. UC was inversely correlated with body mass (r=-0.34, p<0.01 and lean mass (r=- 0.30, p<0.05, and positively correlated with fat mass (r=0.32, p<0.05. After acute exercise, urinary creatine significantly decreased in both athletes and controls. UC is low in sprinters at rest and further decreases after exercise, most likely due to a high uptake and use of creatine by muscles, as muscle mass and physical activity are supposed to be greater in athletes than untrained subjects. Further studies are needed to test the value of urinary creatine as a non-invasive marker of physical condition and as a parameter for managing Cr supplementation in athletes.

  6. Urinary creatine at rest and after repeated sprints in athletes: a pilot study.

    Science.gov (United States)

    Bezrati-Benayed, I; Nasrallah, F; Feki, M; Chamari, K; Omar, S; Alouane-Trabelsi, L; Ben Mansour, A; Kaabachi, N

    2014-03-01

    Creatine plays a key role in muscle function and its evaluation is important in athletes. In this study, urinary creatine concentration was measured in order to highlight its possible significance in monitoring sprinters. The study included 51 sprinters and 25 age- and sex-matched untrained subjects as a control group. Body composition was measured and dietary intake estimated. Urine samples were collected before and after standardized physical exercise. Creatine was assessed by gas chromatography mass spectrometry. Basal urinary creatine (UC) was significantly lower in sprinters than controls (34±30 vs. 74±3 µmol/mmol creatinine, p sprinters at rest and further decreases after exercise, most likely due to a high uptake and use of creatine by muscles, as muscle mass and physical activity are supposed to be greater in athletes than untrained subjects. Further studies are needed to test the value of urinary creatine as a non-invasive marker of physical condition and as a parameter for managing Cr supplementation in athletes.

  7. Security Analysis and Performance Evaluation of Enhanced Threshold Proxy Signature Scheme Based on RSA for Known Signers

    Directory of Open Access Journals (Sweden)

    Raman Kumar

    2012-08-01

    Full Text Available An efficient threshold signature scheme solves the difficulties of the receiver to proof the approval of the document from the sender as well as detecting if the file has been altered by illegitimate parties. In these days there are plenty of signature schemes such as (t,n threshold proxy signature scheme. The network is a shared medium so that the weakness security attacks such as eavesdropping, replay attack and modification attack. Thus, we have to establish a common key for encrypting/decrypting our communications over an insecure network. In this scheme, a (t,n threshold proxy signature scheme based on RSA, any t or more proxy signers can cooperatively generate a proxy signature while t-1 or fewer of them can’t do it. The threshold proxy signature scheme uses the RSA cryptosystem to generate the private and the public key of the signers. Comparison is done on the basis of time complexity, space complexity and communication overhead. We compare the performance of four schemes: Hwang et al., Wen et al., Geng et al. and Fengying et al. with the performance of a scheme that has been proposed by the authors of this article earlier. In the proposed scheme, both the combiner and the secret share holder can verify the correctness of the information that they are receiving from each other. Therefore, the enhanced threshold proxy signature scheme is secure and efficient against notorious conspiracy attacks.

  8. CYP2E1PstI/RsaI polymorphism and interaction with tobacco, alcohol and GSTs in gastric cancer susceptibility: A meta-analysis of the literature.

    NARCIS (Netherlands)

    S. Boccia (Stefania); S. de Lauretis (Angelo); F. Gianfagna (Francesco); C.M. van Duijn (Cock); G. Ricciardi (Gualtiero)

    2007-01-01

    textabstractStudies investigating the association between cytochrome P450 2E1 (CYP2E1) 5'-flanking region (PstI/RsaI) polymorphism and gastric cancer risk report conflicting results. The rationale for this meta-analysis was to determine whether CYP2E1*2 (c2) variant allele of CYP2E1 increases

  9. Repeated high-intensity running and sprinting in elite women’s soccer competition

    OpenAIRE

    Gabbett, Tim J; Wiig, Håvard; Spencer, Matt

    2013-01-01

    Background: To the authors’ knowledge, no study has investigated the concurrent repeated, high-intensity (RHIA) and repeated-sprint activity (RSA) of intermittent team-sport competition. Purpose: In this study, they report on the RSA of elite women’s football competition. In addition, they describe the nature of RHIA (eg, striding and sprinting activities) that involve a high energy cost and are associated with short (ie, ≤20 s) recovery periods. Methods: Thirteen elite women soccer players u...

  10. Implementation of RSA 2048-bit and AES 256-bit with Digital Signature for Secure Electronic Health Record Application

    Directory of Open Access Journals (Sweden)

    Mohamad Ali Sadikin

    2016-10-01

    Full Text Available This research addresses the implementation of encryption and digital signature technique for electronic health record to prevent cybercrime such as robbery, modification and unauthorised access. In this research, RSA 2048-bit algorithm, AES 256-bit and SHA 256 will be implemented in Java programming language. Secure Electronic Health Record Information (SEHR application design is intended to combine given services, such as confidentiality, integrity, authentication, and nonrepudiation. Cryptography is used to ensure the file records and electronic documents for detailed information on the medical past, present and future forecasts that have been given only to the intended patients. The document will be encrypted using an encryption algorithm based on NIST Standard. In the application, there are two schemes, namely the protection and verification scheme. This research uses black-box testing and whitebox testing to test the software input, output, and code without testing the process and design that occurs in the system.We demonstrated the implementation of cryptography in SEHR. The implementation of encryption and digital signature in this research can prevent archive thievery.

  11. Endurance and sprint benefits of high-intensity and supramaximal interval training.

    Science.gov (United States)

    Cicioni-Kolsky, Daniel; Lorenzen, Christian; Williams, Morgan David; Kemp, Justin Guy

    2013-01-01

    This study examined the effect of two different interval training programs-high-intensity interval training (HIT) and supramaximal interval training (SMIT)-on measures of sprint and endurance performance. Physically active individuals (Females: n=32; age 19.3, s=2.2 years; mass 67.6, s=9.1 kg; stature 172.7, s=6.6 cm. Males: n=23; age 20.0, s=2.7 years; mass 71.3, s=8.3 kg; stature 176.6, s=5.8 cm) completed pre-testing that comprised (1) 3000 m time-trial, (2) 40 m sprint, and (3) repeated sprint ability (RSA-6×40 m sprints, 24 s active recovery) performance. Participants were then matched for average 3000 m running velocity (AV) and randomly assigned to one of three groups: (i) HIT, n=19, 4 min at 100% AV, 4 min passive recovery, 4-6 bouts per session; (ii) SMIT, n=20, 30 s at 130% AV, 150 s passive recovery, 7-12 bouts per session; and (iii) control group, n=16, 30 min continuous running at 75% AV. Groups trained three times per week for six weeks. When time to complete each test were compared among groups: (i) improvements in 3000 m time trial performance were greater following SMIT than continuous running, and (ii) improvements in 40 m sprint and RSA performance were greater following SMIT than HIT and continuous running. In addition, a gender effect was observed for the 3000 m time trial only, where females changed more following the training intervention than males. In summary, for concurrent improvements in endurance, sprint and repeated sprint performance, SMIT provides the greatest benefits for physically active individuals.

  12. AN APPROXIMATE EXPRESSION RELATED WITH RSA FIXED POINTS%与RSA不动点有关的一个渐近表示

    Institute of Scientific and Technical Information of China (English)

    于秀源

    2004-01-01

    Let T=T(n,e,α) be the number of fixed points of RSA(n,e) that are co-prime with n=pq,and A,B be sets of prime numbers in (1,x) and (1,y) respectively. An estimation on the mean-valueM(A,B,e,α) = 1(#A)(#B) ∑p∈A,q∈B,(p,q)=1 logT(pq,e,α) is given.

  13. Predicting 3D pose in partially overlapped X-ray images of knee prostheses using model-based Roentgen stereophotogrammetric analysis (RSA).

    Science.gov (United States)

    Hsu, Chi-Pin; Lin, Shang-Chih; Shih, Kao-Shang; Huang, Chang-Hung; Lee, Chian-Her

    2014-12-01

    After total knee replacement, the model-based Roentgen stereophotogrammetric analysis (RSA) technique has been used to monitor the status of prosthetic wear, misalignment, and even failure. However, the overlap of the prosthetic outlines inevitably increases errors in the estimation of prosthetic poses due to the limited amount of available outlines. In the literature, quite a few studies have investigated the problems induced by the overlapped outlines, and manual adjustment is still the mainstream. This study proposes two methods to automate the image processing of overlapped outlines prior to the pose registration of prosthetic models. The outline-separated method defines the intersected points and segments the overlapped outlines. The feature-recognized method uses the point and line features of the remaining outlines to initiate registration. Overlap percentage is defined as the ratio of overlapped to non-overlapped outlines. The simulated images with five overlapping percentages are used to evaluate the robustness and accuracy of the proposed methods. Compared with non-overlapped images, overlapped images reduce the number of outlines available for model-based RSA calculation. The maximum and root mean square errors for a prosthetic outline are 0.35 and 0.04 mm, respectively. The mean translation and rotation errors are 0.11 mm and 0.18°, respectively. The errors of the model-based RSA results are increased when the overlap percentage is beyond about 9%. In conclusion, both outline-separated and feature-recognized methods can be seamlessly integrated to automate the calculation of rough registration. This can significantly increase the clinical practicability of the model-based RSA technique.

  14. Identification of RCN1 and RSA3 as ethanol-tolerant genes in Saccharomyces cerevisiae using a high copy barcoded library.

    Science.gov (United States)

    Anderson, Michael J; Barker, Sarah L; Boone, Charlie; Measday, Vivien

    2012-02-01

    Saccharomyces cerevisiae (S. cerevisiae) encounters a multitude of stresses during industrial processes such as wine fermentation including ethanol toxicity. High levels of ethanol reduce the viability of yeast and may prevent completion of fermentation. The identification of ethanol-tolerant genes is important for creating stress-resistant industrial yeast, and S. cerevisiae genomic resources have been utilized for this purpose. We have employed a molecular barcoded yeast open reading frame (MoBY-ORF) high copy plasmid library to identify ethanol-tolerant genes in both the S. cerevisiae S288C laboratory and M2 wine strains. We find that increased dosage of either RCN1 or RSA3 improves tolerance of S288C and M2 to toxic levels of ethanol. RCN1 is a regulator of calcineurin, whereas RSA3 has a role in ribosome maturation. Additional fitness advantages conferred upon overproduction of RCN1 and RSA3 include increased resistance to cell wall degradation, heat, osmotic and oxidative stress. We find that the M2 wine yeast strain is generally more tolerant of stress than S288C with the exception of translation inhibition, which affects M2 growth more severely than S288C. We conclude that regulation of ribosome biogenesis and ultimately translation is a critical factor for S. cerevisiae survival during industrial-related environmental stress. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  15. Survey of Layer Flocks Contamination to Mycoplasma gallisepticum in East Azerbaijan Province by Rapid Slide Agglutination (R.S.A Method

    Directory of Open Access Journals (Sweden)

    Mehrdad Nazeri

    2012-01-01

    Full Text Available The objective of this study was to evaluation of R.S.A. method efficiency in distinguishing M. gallisepticum and contamination rate of MG in Iran. In this study totally 300 serum samples from 20 farms collected and sent to laboratory. In lab, samples centrifuged at 2500 rpm for 5 min. Separated serums kept in Bain Marie at 56ºC. Then 50 μ of serum are mixed with 50 : RSA-MG antigen on the slide and were assayed under light. Of 300 serum samples, 52 samples (17.3% were positive, 10 samples (3.3% were suspicious and 238 samples (79.3% were negative reported. Finally, primarily can be conclude that R.S.A method is specific method for detection of M. gallisepticum and has minimum Err with maximum sensitivity. Secondarily can be conclude that contamination rate of M. gallisepticum in Iran is higher than standard levels and must be take measures in this field.

  16. Association of Hematological Variables with Team-Sport Specific Fitness Performance.

    Directory of Open Access Journals (Sweden)

    Franck Brocherie

    Full Text Available We investigated association of hematological variables with specific fitness performance in elite team-sport players.Hemoglobin mass (Hbmass was measured in 25 elite field hockey players using the optimized (2 min CO-rebreathing method. Hemoglobin concentration ([Hb], hematocrit and mean corpuscular hemoglobin concentration (MCHC were analyzed in venous blood. Fitness performance evaluation included a repeated-sprint ability (RSA test (8 x 20 m sprints, 20 s of rest and the Yo-Yo intermittent recovery level 2 (YYIR2.Hbmass was largely correlated (r = 0.62, P0.05. [Hb] and MCHC displayed moderate correlations with both YYIR2TD (r = 0.44 and 0.41; both P0.05.Hbmass is positively correlated with specific aerobic fitness, but not with RSA, in elite team-sport players. Additionally, the negative relationships between YYIR2 and RSA tests performance imply that different hematological mechanisms may be at play. Overall, these results indicate that these two fitness tests should not be used interchangeably as they reflect different hematological mechanisms.

  17. Relationships and Predictive Capabilities of Jump Assessments to Soccer-Specific Field Test Performance in Division I Collegiate Players

    Directory of Open Access Journals (Sweden)

    Robert G. Lockie

    2016-12-01

    Full Text Available Leg power is an important characteristic for soccer, and jump tests can measure this capacity. Limited research has analyzed relationships between jumping and soccer-specific field test performance in collegiate male players. Nineteen Division I players completed tests of: leg power (vertical jump (VJ, standing broad jump (SBJ, left- and right-leg triple hop (TH; linear (30 m sprint; 0–5 m, 5–10 m, 0–10, 0–30 m intervals and change-of-direction (505 speed; soccer-specific fitness (Yo-Yo Intermittent Recovery Test Level 2; and 7 × 30-m sprints to measure repeated-sprint ability (RSA; total time (TT, performance decrement (PD. Pearson’s correlations (r determined jump and field test relationships; stepwise regression ascertained jump predictors of the tests (p < 0.05. All jumps correlated with the 0–5, 0–10, and 0–30 m sprint intervals (r = −0.65–−0.90. VJ, SBJ, and left- and right-leg TH correlated with RSA TT (r = −0.51–−0.59. Right-leg TH predicted the 0–5 and 0–10 m intervals (R2 = 0.55–0.81; the VJ predicted the 0–30 m interval and RSA TT (R2 = 0.41–0.84. Between-leg TH asymmetry correlated with and predicted left-leg 505 and RSA PD (r = −0.68–0.62; R2 = 0.39–0.46. Improvements in jumping ability could contribute to faster speed and RSA performance in collegiate soccer players.

  18. 大规模ad hoc网络下的高效的主动RSA方案%An efficient proactive RSA scheme for large-scale ad hoc networks

    Institute of Scientific and Technical Information of China (English)

    张瑞山; 陈克非

    2007-01-01

    A previous proactive RSA scheme for large-scale ad hoc network has been shown to be faulty. In this paper, we present a new proactive RSA scheme for ad hoc networks, which includes four protocols: the initial key distribution protocol,the share refreshing protocol, the share distribution protocol, and the signature generation protocol. This scheme has two advantages: the building blocks are secure, and the system is efficient.

  19. 新月柄杆菌RsaA分泌系统用于大肠杆菌胞外递送重组蛋白的初步研究%Preliminary Study on Exportation of Heterologous Recombinant Proteins in Escherichia coli Utilizing RsaA Secretion System of Caulobacter crescentus

    Institute of Scientific and Technical Information of China (English)

    宁亚蕾; 周立雄; 肖斌; 张卫军; 曾浩; 毛旭虎; 邹全明

    2008-01-01

    目的:构建基于新月柄杆菌RsaA外运机制的以大肠杆菌为宿主的原核胞外分泌表达载体系统.方法:利用分子克隆手段,按RsaA分泌系统操纵子组织方式,将RsaA系统外运功能基因配合以异源调控序列克隆至pQE30骨架质粒.以绿色荧光蛋白(GFP)为报告分子、大肠杆菌M15为宿主菌,诱导表达后通过Western Blotting检测培养上清中GFP的表达.结果:获得了与设计完全一致的pQABPS载体,利用该载体系统,在培养上清中报告分子GFP的表达明显增加,且是通过特异的RsaA外运机制被分泌至胞外的,而非渗漏表达或简单的信号肽引导.结论:在大肠杆菌中重现了RsaA分泌系统的外运功能,为该系统在基因工程领域的应用研究打下了良好基础.

  20. Functional PstI/RsaI polymorphism in CYP2E1 is associated with the development, progression and poor outcome of gastric cancer.

    Directory of Open Access Journals (Sweden)

    Jin Feng

    Full Text Available BACKGROUND: Cytochrome P450 2E1 (CYP2E1, an ethanol-inducible enzyme, has been shown to metabolically activate various carcinogens, which is critical for the development and progression of cancers. It has demonstrated that CYP2E1 polymorphisms alter the transcriptional activity of the gene. However, studies on the association between CYP2E1 polymorphisms (PstI/RsaI or DraI and gastric cancer have reported conflicting results. Thus, the aim of the present study was to investigate whether CYP2E1 polymorphisms is associated with the development and progression of gastric cancer and its prognosis in Chinese patients. METHODS: A case-control study was conducted in which CYP2E1 PstI/RsaI and DraI polymorphisms were analyzed in 510 Chinese patients with gastric cancer and 510 age- and sex- matched healthy controls by PCR-RFLP. Odds ratios were estimated by multivariate logistic regression, and the lifetime was calculated by Kaplan-Meier survival curves. In addition, a meta-analysis was also conducted to verify the findings. RESULTS: For CYP2E1 PstI/RsaI polymorphism, C2C2 homozygotes (OR = 2.15; CI: 1.18-3.94 and C2 carriers (OR = 1.48; CI: 1.13-1.96 were associated with an increased risk of gastric cancer when compared with C1C1 homozygotes. Both C1C2 and C2C2 genotypes were associated with advanced stage, but not the grade of gastric cancer. Moreover, C2C2 genotype was identified as an independent marker of poor overall survival for gastric cancer. However, there was not any significant association between CYP2E1 DraI polymorphism and the risk of gastric cancer. In the meta-analysis, pooled data from 13 studies confirmed that the CYP2E1 PstI/RsaI polymorphism was associated with a significantly increased risk of gastric cancer. CONCLUSION: CYP2E1 PstI/RsaI polymorphism is associated with increased risk of development, progression and poor prognosis of gastric cancer in Chinese patients. Pooled data from 13 studies, mainly in Asian countries, are in

  1. Shuttle-run sprint training in hypoxia for youth elite soccer players: a pilot study.

    Science.gov (United States)

    Gatterer, Hannes; Philippe, Marc; Menz, Verena; Mosbach, Florian; Faulhaber, Martin; Burtscher, Martin

    2014-12-01

    The purposes of the present study were to investigate if a) shuttle-run sprint training performed in a normobaric hypoxia chamber of limited size (4.75x2.25m) is feasible, in terms of producing the same absolute training load, when compared to training in normoxia, and b) if such training improves the repeated sprint ability (RSA) and the Yo-Yo intermittent recovery (YYIR) test outcome in young elite soccer players. Players of an elite soccer training Centre (age: 15.3 ± 0.5 years, height: 1.73 ± 0.07 m, body mass: 62.6 ± 6.6 kg) were randomly assigned to a hypoxia or a normoxia training group. Within a 5-week period, players, who were not informed about the hypoxia intervention, performed at least 7 sessions of identical shuttle-run sprint training either in a normal training room (FiO2 = 20.95%) or in a hypoxic chamber (FiO2 = 14.8%; approximately 3300m), both equipped with the same floor. Each training session comprised 3 series of 5x10s back and forth sprints (4.5m) performed at maximal intensity. Recovery time between repetitions was 20s and between series 5min. Before and after the training period the RSA (6 x 40m shuttle sprint with 20 s rest between shuttles) and the YYIR test were performed. The size of the chamber did not restrict the training intensity of the sprint training (both groups performed approximately 8 shuttles during 10s). Training in hypoxia resulted in a lower fatigue slope which indicates better running speed maintenance during the RSA test (p = 0.024). YYIR performance increased over time (p = 0.045) without differences between groups (p > 0.05). This study showed that training intensity of the shuttle-run sprint training was not restricted in a hypoxic chamber of limited size which indicates that such training is feasible. Furthermore, hypoxia compared to normoxia training reduced the fatigue slope during the RSA test in youth soccer players. Key PointsShuttle-run sprint training is feasible in hypoxic chambers of limited size (i

  2. IVR RSA Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This database contains trip-level reports submitted by vessels participating in Research Set-Aside projects with IVR reporting requirements.

  3. Neurophysiological Mechanisms of Fatigue Résistance during Repeated Sprints in Hot and Hypoxic Environments: Application to Team Sports

    OpenAIRE

    Brocherie, Franck

    2016-01-01

    In team sports, characterising fatigue is complex, with the underlying processes (e.g., metabolic energy supply, intramuscular accumulation of metabolic by-products, hyperthermia, dehydration) developing as match proceeds to ultimately manifest as a decline in physical performance. Using acute and chronic manipulations of environmental stress (i.e., heat or hypoxia) and unique tools (i.e., instrumented sprint treadmill, 45-m long hypoxic marquee), the main intention of this work was to better...

  4. Attentional and visual demands for sprint performance in non-fatigued and fatigued conditions : reliability of a repeated sprint test

    NARCIS (Netherlands)

    Reininga, Inge H. F.; Lemmink, Koen A. P. M.; Diercks, Ron L.; Buizer, Arina T.; Stevens, Martin

    2010-01-01

    Background: Physical performance measures are widely used to assess physical function, providing information about physiological and biomechanical aspects of motor performance. However they do not provide insight into the attentional and visual demands for motor performance. A figure-of-eight sprint

  5. Differential Timing Attack Against the Software Implementation of RSA%一种针对RSA算法软件应用的差分计时攻击

    Institute of Scientific and Technical Information of China (English)

    陈财森; 王韬; 田军舰

    2011-01-01

    The former timing attack against RSA algorithm is either just in theory research, or taken in experiment under specifical condition. The object of timing attack mostly is smart card. The former has the disadvantage of low feasibility and small range. We aim to overcome the disadvantage. This thesis provides a feasible timing attack scheme, based the differential statistics algorithm and analysis of variance. Finally we take the attack scheme into practice on the software implementation of RSA, the result indicates that our attack scheme has a better feasibility than the former, and also extend the attack object to RSA with different length key.%原有针对一般RSA算法的计时攻击方式不是只在理论上进行研究,就是在某种特定的条件下进行实验,其主要研究对象是智能卡,具有可行性不高、攻击范围狭窄等缺点.在深入研究分析RSA实现算法基础上,结合差分统计分析方法,引入方差分析假设检验,提出一种可行的计时攻击算法,并针对RSA算法的软件应用进行攻击验证,结果表明提出的攻击方案不仅比传统攻击方式具有更高的可行性,而且能够适用于不同密钥长度的攻击.

  6. File Encryption System Based on Triple DES and RSA%基于Triple DES与RSA的文件加密系统

    Institute of Scientific and Technical Information of China (English)

    胡振

    2012-01-01

    Comparing the characteristics of symmetric cryptography and asymmetric cryptography, this paper outlines the basic principles of the Triple DES algorithm and the RSA algorithm. On the basis of a detailed analysis of issues related to file security and in-depth study on . NET Framework encryption algorithm class, this paper proposes the file encryption scheme on the combination of the Triple DES algorithm and the RSA algorithm, designs the system' s overall structure and the basic process, then the system is realized with VB. NET. After practice, the results show that the system is simple and convenient for file encryption.%比较对称密码体制与非对称密码体制的特点,简述Triple DES算法与RSA算法的基本原理.在详细分析文件安全的相关问题和深入研究.NET Framework密码算法类的基础上,提出Triple DES算法与RSA算法结合运用的文件加密方案,设计系统的总体结构和基本流程,并以VB.NET实现了基于Triple DES与RSA的文件加密系统.实践表明,用本系统进行文件加密简单而方便.

  7. 基于RSA的数字图像加密算法%An Encryption Algorithm for Digital Image Based on RSA System

    Institute of Scientific and Technical Information of China (English)

    杨昔阳; 李志伟

    2009-01-01

    It proposes a novel encryption method for digital image based on an Arnold scrambling transform, a chaos encryption algorithm and RSA encryption system. The parameters of the Arnold transform and chaos encryption algorithm are encrypted by RSA system and stored in LSB of an image to ensure the security in transmission. The example in this paper shows that the proposed method is an efficient way to encrypt a digital image.%提出一种基于RSA公钥、Arnold置乱变换和混沌加密算法相结合的公开密钥数字图像加密体制,利用客户的公钥对Arnold置乱变换和混沌序列初值进行RSA加密,确保了只有合法用户才能获取置乱参数信息并将图像复原.RSA对参数的加密信息隐藏于图像LSB中,无需另外传递密文,运算简单,具有良好的加密与隐藏效果.

  8. Cache Timing Attack on RSA Sliding Window Algorithm%针对RSA滑动窗口算法的Cache计时攻击

    Institute of Scientific and Technical Information of China (English)

    田军舰; 寇应展; 陈财森; 高靖哲; 曾剑隽

    2011-01-01

    Based on researching RSA signature algorithm and theory of cache timing attack, analyzing the implementation of RSA in OpenSSL0.9.8a, a caching timing attack method is given against the process of accessing initial table in the sliding windows algorithm. Simulation result demonstrates the cache timing attack can get more than 700 bit secret key from 1 024 bit private key and needs less samples compare to the timing attack based on statistic analysis.%研究RSA签名算法和Cache计时攻击原理,分析OpenSSL0.9.8a中的RSA实现过程,针对RSA滑动窗口算法中的访问初始化表操作,提出一种Cache计时攻击方法.实验结果表明,该方法在1次攻击中可获得1 024 bit密钥中700 bit以上的密钥,与传统基于统计方法的计时攻击相比,所需样本更少.

  9. Timing and Estimates of Plio-Pleistocene Sea-Level Highstands from the Republic of South Africa (RSA)

    Science.gov (United States)

    Hearty, Paul; Raymo, Maureen; Sandstrom, Michael; Rovere, Alessio; O'Leary, Michael

    2016-04-01

    The rapid rise in atmospheric CO2 exceeding 400 ppmv is driving an urgent need to better understand past sea level, ice sheet dynamics, and climate change associated with past warmer geological intervals. The LR04 record reveals sustained intervals during the Pliocene (5.6-2.6 Ma) when δ18O exceeded the present levels, indicating a possible decrease in the volume of polar ice sheets. Other shorter intervals of likely decreased ice volume occur during Pleistocene interglacials including MIS 5e, 11, 31, and 37.Here we focus on the middle Pliocene warm period (MPWP; 3.3 to 2.9 Ma), an interval during which Earth experienced CO2 levels around 400 ppmv (Fedorov et al., 2013). The intra-plate coastal margin of western South Africa, a region of relative tectonic stability and relative insensitivity to uncertainty in mantle viscosity as is effects corrections for glacial isostatic adjustment, is a promising region for deriving estimates of eustatic sea level (ESL; thus ice volumes) at the end of the MPWP (Rovere et al., 2014). During a field expedition covering several thousand kilometres along coastlines of western and southern coasts of RSA, we documented the stratigraphy, geomorphology, and geochronology of Pliocene and Pleistocene shorelines with differential GPS providing decimeter scale accuracy to stratigraphic contacts and sea-level indicators. From about twenty sites, precise elevations (as yet uncorrected for GIA) of multiple sea stands were recorded. Strontium isotopes were used to date the shell material from many of the marine sites, but only three sites yielded reliable age data that passed screening criteria for diagenesis. The oldest shoreline evidence, from Cliffs Point on the west coast near the Olifants River, is observed at 34.9 ±0.2 m asl and yields an age 4.70 ± 0.20 Ma; a younger shoreline from the southern coast Bredasdorp site is observed at >24.0 ± 1.5 m asl and yields ages from 3.00 ± 0.45 to 3.55 ± 0.31 Ma, the interval of the MPWP. . A

  10. Anthropometric and physiological characteristics of Melanesian futsal players: a first approach to talent identification in Oceania

    Directory of Open Access Journals (Sweden)

    Olivier Galy

    2015-02-01

    Full Text Available This study assessed the anthropometric and physiological characteristics of elite Melanesian futsal players in order to determine the best performance predictors. Physiological parameters of performance were measured in 14 Melanesian (MEL-G, 24.4±4.4 yrs and 8 Caucasian (NMEL-G, 22.9±4.9 elite futsal players, using tests of jump-and-reach (CMJ, agility (T-Test, repeated sprint ability (RSA, RSA with change-of-direction (RSA-COD, sprints with 5 m, 10 m, 15 m, and 30 m lap times, and aerobic fitness with the 30-15 intermittent fitness test (30-15 IFT. The anthropometric data revealed significantly lower height for MEL-G compared with NMEL-G: 1.73±0.05 and 1.80±0.08 m, respectively; P=0.05. The CMJ was significantly higher for MEL-G than NMEL-G: 50.4±5.9 and 45.2±4.3 cm, respectively; P=0.05. T-Test times were significantly lower for MEL-G than NMEL-G: 10.47±0.58 and 11.01±0.64 seconds, respectively; P=0.05. MEL-G height was significantly related to CMJ (r=0.706, P=0.01, CMJ peakP (r=0.709, P=0.01 and T-Test (r=0.589, P=0.02. No significant between-group differences were observed for sprint tests or 30-15 IFT, including heart rate and estimated VO 2max . Between groups, the percentage decrement (%Dec in RSA-COD was significantly lower in MEL-G than NMEL-G (P=0.05, although no significant difference was noted between RSA and RSA-COD. Within groups, no significant difference was observed between %Dec in RSA or RSA-COD; P=0.697. This study presents specific anthropometric (significantly lower height and physiological (significantly greater agility reference values in Melanesians, which, taken together, might help coaches and physical fitness trainers to optimize elite futsal training and talent identification in Oceania.

  11. Efectos de 2 Tipos de Entrenamiento Interválico de Alta Intensidad en la Habilidad para Realizar Esfuerzos Máximos (RSA Durante una Pretemporada de Fútbol

    Directory of Open Access Journals (Sweden)

    Alejandro Rodríguez Fernández

    2014-01-01

    Full Text Available El trabajo de pretemporada persigue mejorar el rendimiento del futbolista tanto en lo referente a la habilidad para realizar esfuerzos máximos como a su capacidad aeróbica y de recuperación. El objetivo de este estudio fue comparar durante una pretemporada los efectos de 2 programas de entrenamiento interválicos con series de diferente duración en la habilidad de repetir sprints (RSA. Diecinueve jugadores de fútbol con valores medios ± SD de 20,9 ± 1,6 años de edad; 68,8 ± 5,1 Kg de peso; 176,1 ± 5,1 cm de altura; y 9,6 ± 2,4% de grasa corporal fueron asignados al azar al grupo de Speed Endurance Training (SET para realizar 2x10 min con 10, 15 y 20 s al 100% con 30, 45 y 60 s de recuperación (n = 9, o al grupo High Interval Training (HIT para realizar 4x4 min al 95% FCmax (n = 10. Un test RSA de 8x30 m con 25 s de recuperación activa fue realizado antes y después de la intervención (10 sesiones de entrenamiento junto con un Yo-Yo Intermittent Recovery Test level 1 en la evaluación inicial. Tanto SET como HIT ven incrementado su rendimiento de forma significativa (p < 0,05 en RSAmejor (3,12% y 3,59% respectivamente y muy significativamente (p < 0,01 en RSAmedia (3,00% y 3,91% y RSAtotal (3,12% y 4,08%, pero sin cambios significativos en los índices de fatiga (Sdec y Change. Estos resultados demuestran que tanto la intervención SET como HIT se han mostrado útiles para aumentar el rendimiento en algunas de las variables determinantes en el test RSA, durante el periodo de pretemporada.

  12. Static stretching can impair explosive performance for at least 24 hours.

    Science.gov (United States)

    Haddad, Monoem; Dridi, Amir; Chtara, Moktar; Chaouachi, Anis; Wong, Del P; Behm, David; Chamari, Karim

    2014-01-01

    The aim of this study was to compare the effects of static vs. dynamic stretching (DS) on explosive performances and repeated sprint ability (RSA) after a 24-hour delay. Sixteen young male soccer players performed 15 minutes of static stretching (SS), DS, or a no-stretch control condition (CC) 24 hours before performing explosive performances and RSA tests. This was a within-subject repeated measures study with SS, DS, and CC being counterbalanced. Stretching protocols included 2 sets of 7 minutes 30 seconds (2 repetitions of 30 seconds with a 15-second passive recovery) for 5 muscle groups (quadriceps, hamstring, calves, adductors, and hip flexors). Twenty-four hours later (without any kind of stretching in warm-up), the players were tested for the 30-m sprint test (with 10- and 20-m lap times), 5 jump test (5JT), and RSA test. Significant differences were observed between CC, SS, and DS with 5JT (F = 9.99, p effect size [ES] = 0.40), 10-m sprint time (F = 46.52, p stretching protocols in the total time (F = 1.55, p > 0.05), average time (F = 1.53, p > 0.05), and fastest time (F = 2.30, p > 0.05), except for the decline index (F = 3.54, p negative effect on explosive performances up to 24 hours poststretching with no major effects on the RSA. Conversely, the DS of the same muscle groups are highly recommended 24 hours before performing sprint and long-jump performances. In conclusion, the positive effects of DS on explosive performances seem to persist for 24 hours.

  13. Efectos sobre el estado de ánimo en jóvenes tenistas de diferentes volúmenes de entrenamiento de alta intensidad

    Directory of Open Access Journals (Sweden)

    Manuel Moya

    2016-01-01

    Full Text Available El objetivo de este estudio fue analizar la influencia del incremento de la carga de entrenamiento por medio del método Repeated Sprint Ability (RSA sobre el estado de ánimo de jóvenes tenistas. Participaron 30 tenistas (15.78 ± 1.58 a ̃ nos en este programa de entrena- miento (7 semanas. Los sujetos fueron divididos en tres grupos: G1, volumen de entrenamiento de tenis más un incremento del 8.3% por medio de RSA; G2, ídem más un incremento de 16.6% de RSA; y G3, entrenamiento de tenis. El entrenamiento específico de tenis fue controlado e igualado, además se cumplimentó un cuestionario semanal para establecer el perfil de estado de ánimo (Balaguer, Fuentes, Meliá, García-Mérita & Pons, 1995. Los resultados mostraron variaciones en G1 y G2. Mientras en G1 las puntuaciones de los factores tensión y fatiga se incrementaron al final del programa ( p < .05, en G2 aumentaron las puntuaciones de tensión, depresión, hostilidad y fatiga al comienzo del programa, y se redujeron significativamente al final ( p < .05. En G3 no hubo modificaciones. La diferente evolución del estado de ánimo de los sujetos en función del volumen de entrenamiento de RSA realizado, muestra la necesidad de monitorizar la carga interna para ajustar este entrenamiento

  14. Preseason Training: The Effects of a 17-Day High-Intensity Shock Microcycle in Elite Tennis Players

    Directory of Open Access Journals (Sweden)

    Jaime Fernandez-Fernandez, David Sanz-Rivas, Jose Manuel Sarabia, Manuel Moya

    2015-12-01

    Full Text Available Preseasons in tennis are normally reduced to 5 to 7 weeks duration, and coaches should use an integrated approach to conditioning and skill-based work. The aim of the present study was to investigate the effects of adding a high-intensity training (HIT shock microcycle to the normal training content in several physical performance indicators in the preseason training of high-level male tennis players. Over 17 days, 12 male tennis players performed 13 HIT sessions in addition to their usual training. Physical performance tests (30:15 intermittent fitness test [VIFT], 20 m sprint, countermovement jump [CMJ], repeated sprint ability [RSA] were conducted before (pre-test and 5 days after the intervention (post-test. After the shock microcycle, results showed a significant increase in the VIFT (p < 0.001; Large ES and a significant decrease in the mean RSA time (RSAm (p = 0.002; Small ES, while there were no significant changes in the other parameters analysed (e.g., 20 m, CMJ, best RSA time [RSAb]; percentage of decrement in the RSA [%Dec]. Moreover, the training load (TL during tennis sessions was significantly higher (p < 0.01; Large ES than the TL during the integrated sessions, except during the first training session. A 17-day shock microcycle (i.e., 13 HIT sessions in addition to the regular tennis training significantly improved parameters that can impact physical performance in tennis. Moreover, additional sessions, including running exercises based on the 30:15ITF and on-court specific exercises, were characterised by significantly lower TL than tennis-training sessions.

  15. Does small-sided-games’ court area influence metabolic, perceptual, and physical performance parameters of young elite basketball players?

    Directory of Open Access Journals (Sweden)

    PR Marcelino

    2016-01-01

    Full Text Available The purpose of this study was to investigate the effect of court size on physiological responses and physical performance of young elite basketball players. Twelve male basketball players (18.6 ± 0.5 years; 88.8 ± 14.5 kg; 192.6 ± 6.5 cm from an under-19 team performed two small-sided games (matches with different court areas (28x15 m and 28x9 m; 28x15 and 28x9 protocols. The number of players (3x3 was kept the same in each protocol. The players performed a repeated-sprint ability (RSA test before and after each match. Blood lactate concentration was collected before (pre and after (post the matches, and the session rating of perceived exertion (session-RPE was determined 30 minutes after the match. Best and mean time in the RSA test were not different between the 28x15 and the 28x9 match protocols (p>0.05. A significant difference was observed for lactate concentration from pre- to post-match (p 0.0S, ES=(0.41. In summary, the results of the current study suggest that the different court areas induced similar responses. Although there was no significant difference in effort perception, players tended to perceive a greater effort in the larger court size.

  16. Fitness Field Tests' Correlation With Game Performance in U-19-Category Basketball Referees.

    Science.gov (United States)

    Nabli, Mohamed Ali; Abdelkrim, Nidhal Ben; Jabri, Imed; Batikh, Tahar; Castagna, Carlo; Chamari, Karim

    2016-11-01

    To examine the relation between game performance, physiological responses, and field-test results in Tunisian basketball referees. Computerized time-motion analysis, heart rate (HR), and blood lactate concentration [La(-)] were measured in 15 referees during 8 competitive games (under-19-y-old Tunisian league). Referees also performed a repeated-sprint test (RSA), Yo-Yo Intermittent Recovery Test level 1 (YYIRTL1), agility T-test, and 30-m sprint with 10-m lap time. Computerized video analysis determined the time spent in 5 locomotor activities (standing, walking, jogging, running, and sprint), then grouped in high-, moderate-, and low-intensity activities (HIAs, MIAs, and LIAs, respectively). YYIRTL1 performance correlated with (1) total distance covered during the 4th quarter (r = .52, P = .04) and (2) distance covered in LIA during all game periods (P basketball referees and (2) referees' RSA correlates with the amount of HIA performed during the 2nd half, which represents the ability to keep up with play.

  17. The effect of morphological characteristics on the physical and physiological performance of Turkish soccer referees and assistant referees

    Directory of Open Access Journals (Sweden)

    Bozdoğan Tuba Kızılet

    2017-01-01

    Full Text Available Physical fitness and physiological status play an important role in the referees’ performance. Therefore, the aim of this study was to analyze the body structure and morphological characteristics of Turkish Ssccer refereesand assistant referees and to determine the effect of these variables on physical performance. A sample of 158 male referees and 55 asisstant referees (mean age 31.8 ± 4.2 and 37.4 ± 3.3 yearswas evaluated. Physical assesment were conducted using the Yo-Yo Intermittent Recovery Test Level 1 (YYIRTL1 and Repeated Sprint Ability (RSA for referees and Active Recovery Intermittent Endurance Test (ARIET and the RSA for assistant referees. We analyzed heart rate assesments. The measures used to assess morphological characteristics were age, weight, body mass index (BMI, body fat (BF, body mass, and fat free mass.The ANOVA test (Tukey testwas used to determine the result. Correlations between the referees’ fitness test performance and their morphological characteristics were examined using Pearson’s correlation (p<0.05. To result of this study, point to the existence of a strong correlation between morphological and physical and physiological characteristics. According to the literature, we found that greater BF and a higher BMI may negatively affect areferee’s running performance.

  18. Acute Effects of Two Different Resistance Circuit Training Protocols on Performance and Perceived Exertion in Semiprofessional Basketball Players.

    Science.gov (United States)

    Freitas, Tomás T; Calleja-González, Julio; Alarcón, Francisco; Alcaraz, Pedro E

    2016-02-01

    This study aimed to investigate the acute effects of two different resistance circuit training protocols on basketball players' physical and technical performance and rating of perceived exertion (RPE). In a repeated-measures, crossover experimental design, 9 semiprofessional basketball players performed a Power Circuit Training (PCT; 45% 1RM) and a High-Resistance Circuit Training (HRC; 6RM), on consecutive weeks. Vertical and horizontal jump performance, 3-points shooting accuracy, repeated-sprint ability (RSA), agility, and upper body power output were measured before and after training. The RPE was assessed 20 minutes after resistance training. One-way repeated-measures analysis of variance showed performance decrements in vertical jump height and peak power, horizontal jump distance, 3-points percentage, bench-press power output, RSA total and ideal time, and agility T-Test at total time following HRC, but not PCT (p ≤ 0.05). The RPE was higher in HRC compared with PCT. The results of this study indicated that HRC was perceived as being harder and produced higher fatigue levels, which in turn lowered acute performance. However, low-to-moderate intensity loads did not negatively affect performance. Thus, completing a PCT session may be the most appropriate option before a practice or game as it avoids acute-resistance-training-induced performance decrements. However, if the objective of the basketball session is to develop or perfect technical skills during fatiguing conditions, HRC may be the more suitable option.

  19. 基于新月柄杆菌RsaA外运机制的EspA及EspA-IL-24融合蛋白胞外分泌表达研究%Study on Extracellular Expression of EspA and EspA-IL-24 Proteins in Escherichia coli Following RsaA Exportation Mechanism of Caulobacter crescentus

    Institute of Scientific and Technical Information of China (English)

    宁亚蕾; 周立雄; 毛旭虎; 张卫军; 程琰; 余抒; 邹全明

    2008-01-01

    目的:实现大肠杆菌分泌蛋白(Esp)A及EspA与白细胞介素(IL)-24融合蛋白的胞外分泌表达,进一步验证基于新月柄杆菌RsaA外运机制的原核胞外分泌表达载体系统的有效性和通用性,并改造优化该系统.方法:利用分子克隆手段,按RsaA分泌系统操纵子组织方式,将获得的RsaA系统元件编码序列和异源调控序列克隆至pQE30骨架质粒,构建新的胞外分泌表达质粒pQABP2S;以大肠杆菌为宿主菌诱导表达EspA及EspA-IL-24融合蛋白,并通过Western blot检测目标蛋白在培养上清中的表达.结果:获得了新的胞外分泌表达载体pQABP2S;与对照相比,该载体宿主系统培养上清中目标蛋白EspA及EspA-IL-24的表达量明显增加.结论:在大肠杆菌中通过RsaA分泌系统可实现分子大小不同的EspA及EspA-IL-24融合蛋白的特异性分泌表达,进一步证实该分泌表达策略的有效性和通用性;调整调控序列以优化分泌系统的尝试,为此类基因工程技术平台的开发提供了借鉴.

  20. Yo-Yo IR2 testing of elite and sub-elite soccer players

    DEFF Research Database (Denmark)

    Ingebrigtsen, Jørgen; Bendiksen, Mads; Randers, Morten Bredsgaard

    2012-01-01

    Abstract We examined performance, heart rate response and construct validity of the Yo-Yo IR2 test by testing 111 elite and 92 sub-elite soccer players from Norway and Denmark. VO(2)max, Yo-Yo IR1 and repeated sprint tests (RSA) (n = 51) and match-analyses (n = 39) were also performed. Yo-Yo IR2...

  1. Conceptions of Ability.

    Science.gov (United States)

    Jagacinski, Carolyn M.; Nicholls, John G.

    Two different conceptions of ability are proposed. The first conception of ability is more differentiated and generally employed by adults and older children. Here ability level is defined with reference to the performance of others assuming that optimum effort was employed. High ability means higher than others. The second conception of ability…

  2. 改进的RSA算法在数字签名中的应用%Improved RSA algorithm and application in digital signature

    Institute of Scientific and Technical Information of China (English)

    肖振久; 胡驰; 陈虹

    2014-01-01

    In order to enhance the operation efficiency of RSA algorithm, a new improved algorithm is suggested in this paper which makes some improvements in structure and operation, and it is applied to digital signature. The experiment makes comparison between a combinatorial optimization algorithm which combines SMM with index of 2k hexadecimal algorithm and the new algorithm. It shows that the new algorithm reaches a high level in operation speed.%针对传统RSA密码算法运算效率较低的问题,在标准RSA密码算法的自身结构和具体运算操作两方面做出了相应的改进,提出了一种新的RSA密码优化算法,并将该算法运用到数字签名技术中。然后通过仿真实验,将其与传统RSA算法以及基于乘同余对称特性的SMM算法和指数2k进制化相结合的组合优化算法相比较,实验结果表明新的RSA密码优化算法在提升运算速度方面达到了较高的水平。

  3. 基于RSA的叛逆者追踪方案的设计与分析%The Analysis and Design of Traitor Tracing Scheme Based on RSA

    Institute of Scientific and Technical Information of China (English)

    齐亚莉

    2012-01-01

    叛逆者追踪方案是版权保护中的重要工具。基于RSA算法的安全性,设计叛逆者追踪方案,数据分发者分别为每个用户进行初始化,使每个用户都具有标志性的用户信息,可准确地追踪到叛逆者。对方案进行分析后得出结论:为保证安全性,需要不断增加密钥长度,但其不可否认性和防诬陷性使该追踪算法的应用受到一定限制。%Traitor tracing technology is an important measure to data copyright protection. This paper designs a traitor tracing scheme based on RSA, which dispatches special information for every users respectively. The information for one user is the label of him. The scheme has the advantages of tracing traitor and revoking traitor successfully. But it is restrained by non-re- pudiation and full frameproof to application.

  4. Reliability and validity of resilience scale for adults(RSA) in military students%成人心理弹性量表在军校大学生中的信效度研究

    Institute of Scientific and Technical Information of China (English)

    张佳佳; 任景敏; 黄健; 李敏; 魏琳; 张钰; 李培培; 张丽丽; 汪涛

    2010-01-01

    目的 研究成人心理弹性量表(RSA)在军校大学生中的信效度.方法 采用成人心理弹性量表(RSA)和症状自评量表(SCL-90)中的抑郁、焦虑、躯体化3个因子对某军校616名学生进行整群抽样调查.结果 ①对RSA采用探索性因素分析.共提取5个因子.各项目在因子上的负荷在0.423~0.834之间,累计方差解释率为58.439%;②RSA各因子之间相关显著.相关系数在0.228~0.580之间;各因子与总分相关显著,相关系数在0.565~0.789之间;③效标SCL-90的抑郁、焦虑和躯体化三个因子的均分与RSA均分之间呈显著负相关,相关系数为-0.437(n=593,P=0.000);④RSA各个因子的同质性信度在0.52~0.86之间,RSA问卷信度为0.91.结论 RSA量表在军校学生中信效度较好.%Objective To research the reliability and validity of resilience scale for adults(RSA)in military students.Methods RSA, depression, anxiety and somatization of Self-report Symptom Checklist 90(SCL-90)were applied in this survey to 616 military students.Results ①A 5-factor structure of resilience was showed by explorative factor analysis.Each item had a factor loading between 0.423~0.834, and the total variance explained at 58.439%.②The correlations between the subscales of the RSA were all obvious positive, ranging from 0.228~0.580;and the correlations between subscales of the RSA and total resilience were all obvious positive, ranging from 0.565~0.789.③There was a obvious negative correlation between total depression, anxiety and somatization and total resilience, the correlation coefficient was-0.437(n=593, P=0.000).④Tbe reliability coefficient of the RSA was 0.91, and the respective dimensions had Cronbach's alphas between 0.52~0.86.Conclusion The results show that RSA has acceptable reliability and validity in military students.

  5. RSA加密算法的有效实现及在云计算中的应用%Analysis to Effective Realization of RSA Encryption Algorithm and Its Application in the Cloud Computing

    Institute of Scientific and Technical Information of China (English)

    谢会娟; 韩昌豪; 吴明珠

    2014-01-01

    随着互联网的发展,云计算模式能够提供便捷的、可用的和按需要网络资源,云计算的核心是如何存储和管理用户的数据,除了配置存储设备的之外,还要考虑到存储在云中的数据的安全性。RSA加密算法是基于一个比较简单的数论-两个大素数相乘十分容易实现,但要对它的乘积进行因式分解却十分困难,RSA加密算法是将乘积公开作为加密密钥的非对称加密方法,在云计算中应用RSA算法对存储在云中的数据进行加密,能够保证了数据的安全性。%With the development of the Internet, cloud computing can provide convenient and available network resources, the core of cloud computing is how to store and manage user data, cloud computing does not provide storage devices, but also takes into account the security of the data stored in the cloud. RSA encryption algorithm is based on a relatively simple theory of math-multiplying two large prime numbers is very easy to achieve, but it's the factorization is very difficult, RSA encryption al⁃gorithm considers a product as a public encryption key and is an asymmetric encryption method. To ensure the security of the da⁃ta, RSA encryption algorithm is applied for the data storage in the cloud.

  6. Markers for Routine Assessment of Fatigue and Recovery in Male and Female Team Sport Athletes during High-Intensity Interval Training.

    Directory of Open Access Journals (Sweden)

    Thimo Wiewelhove

    Full Text Available Our study aimed to investigate changes of different markers for routine assessment of fatigue and recovery in response to high-intensity interval training (HIIT.22 well-trained male and female team sport athletes (age, 23.0 ± 2.7 years; V̇O2 max, 57.6 ± 8.6 mL · min · kg(-1 participated in a six-day running-based HIIT-microcycle with a total of eleven HIIT sessions. Repeated sprint ability (RSA; criterion measure of fatigue and recovery, countermovement jump (CMJ height, jump efficiency in a multiple rebound jump test (MRJ, 20-m sprint performance, muscle contractile properties, serum concentrations of creatinkinase (CK, c-reactive protein (CRP and urea as well as perceived muscle soreness (DOMS were measured pre and post the training program as well as after 72 h of recovery.Following the microcycle significant changes (p < 0.05 in RSA as well as in CMJ and MRJ performance could be observed, showing a decline (%Δ ± 90% confidence limits, ES = effect size; RSA: -3.8 ± 1.0, ES = -1.51; CMJ: 8.4 ± 2.9, ES = -1.35; MRJ: 17.4 ± 4.5, ES = -1.60 and a return to baseline level (RSA: 2.8 ± 2.6, ES = 0.53; CMJ: 4.1 ± 2.9, ES = 0.68; MRJ: 6.5 ± 4.5, ES = 0.63 after 72 h of recovery. Athletes also demonstrated significant changes (p < 0.05 in muscle contractile properties, CK, and DOMS following the training program and after the recovery period. In contrast, CRP and urea remained unchanged throughout the study. Further analysis revealed that the accuracy of markers for assessment of fatigue and recovery in comparison to RSA derived from a contingency table was insufficient. Multiple regression analysis also showed no correlations between changes in RSA and any of the markers.Mean changes in measures of neuromuscular function, CK and DOMS are related to HIIT induced fatigue and subsequent recovery. However, low accuracy of a single or combined use of these markers requires the verification of their applicability on an individual basis.

  7. Heart rate recovery after aerobic and anaerobic tests: is there an influence of anaerobic speed reserve?

    Science.gov (United States)

    Del Rosso, Sebastián; Nakamura, Fabio Y; Boullosa, Daniel A

    2017-05-01

    The present study assessed if differences in the metabolic profile, inferred from the anaerobic speed reserve (ASR), would influence the dynamics of heart rate recovery (HRR) after two modes of exercise. Thirty-nine physical education students (14 females and 25 males) volunteered for this study. Participants carried out three separate testing sessions to assess maximal sprinting speed (MSS, 1st session), repeated sprint ability (RSA, 2nd session) and maximal aerobic speed (MAS) using the Université of Montreal Track Test (UMTT, 3rd session). ASR was defined as the difference between MSS and MAS. Heart rate was continuously registered throughout the tests and during the 5-min post-test recovery. To evaluate the influence of ASR on post-exercise, HRR comparisons between ASR-based groups [high ASR vs. low ASR] and sex groups (males vs. females) were performed. Significant differences (P < 0.05) were found between high ASR and low ASR groups of the same sex for indices of relative HRR after the RSA and UMTT. In addition, after the RSA test, males from the high ASR group had a significantly slower HRR kinetics compared with the males of the low ASR (P < 0.05) and the females of high ASR (P < 0.05); whereas females of the high ASR groups had a faster HRR kinetics compared with the females of low ASR group (P < 0.05). Our results showed that in males, post-exercise HRR could be related to the ASR, whereas in females, the influence of ASR is less clear.

  8. 网络信息加密RSA算法的运算速度和保密性优化%Optimization of Operation Speed and Confidentiality of Network Information Encryption RSA Algorithm

    Institute of Scientific and Technical Information of China (English)

    许柯; 刘绪崇; 符振艾; 徐宇宏

    2015-01-01

    According to traditional RSA algorithm has low speed of computing and bad encryption result for encrypting the network information, this article puts forward the RSA encryption algorithm of network information with relevant improved SMM algorithm. The first step is to optimize the modulus and multiplication time of SMM algorithm, the second step is to use the improved SMM algorithm to optimize the RSA algorithm, aiming at the modified algorithm of binary hamming weight in the index, the purpose is to reduce the iteration number, eventually improve the encryption of original algorithm. Seen from the algorithm simulation results, compared with SMM algorithm, the proposed RSA network information encryption algorithm based on improved SMM algorithm and traditional RSA encryption algorithm has faster process of encryption and decryption, and has stronger encryption effect.%针对传统RSA算法在对网络信息进行加密的时候还存在运算速度不快、加密效果不好的问题,本文提出有关改进SMM算法的RSA网络信息加密算法,第一步是针对SMM算法的求模运算量以及乘法时间进行优化操作,第二步是使用改进的SMM算法对RSA算法进行优化,针对其算法的二进制指数中的汉明重量进行改良,目的是为了减少迭代数,最终提升原来算法的加密功能。通过算法仿真实验结果可以看出,本文提出的基于改进SMM算法的RSA网络信息加密算法以及传统RSA加密算法,再与SMM算法进行比较,加密以及解密过程的速度更快,并且加密效果更强。

  9. RSA算法中Z*(φ)(n)的代数结构研究%Study on Algebraic Structure of Z*(φ)(n) in RSA Algorithm

    Institute of Scientific and Technical Information of China (English)

    裴东林; 胡建军; 李旭

    2013-01-01

    [Abstract] Based on the theory of quadratic residues, this paper considers the algebraic structure of Z*φ(n) in the two order strong RSA algorithm. It is proved that the element α of Z*φ(n) gets maximal order if and only if gcd(α±l,n1) = 1, and the numbers of quadratic residues in the group Z*φ(n) is φ(φ(n))/8 .Z*φ(n) is divided up by the group which is composed of all quadratic residues, and all cosets form a Klein eight-group. It proves that the group Z*φ(n) can be generated by seven elements of quadratic non-residues.%应用二次剩余理论,对二阶强RSA算法中Z*(φ)(n)的代数结构进行研究,证明Z*(φ)(n)中元素a取最大阶的充要条件为gcd(a±1,n1)=1,以及任意元素的阶Z*(φ)(n)中模(φ)(n)的二次剩余个数为(φ)(φ)(n))/8,以所有二次剩余构成的群对Z*(φ)(n)进行分割,利用所有陪集构成一个Klein八元群,在此基础上证明Z*(φ)(n)可由7个二次非剩余元素生成.

  10. Displacement of the medial meniscus within the passive motion characteristics of the human knee joint: an RSA study in human cadaver knees.

    Science.gov (United States)

    Tienen, T G; Buma, P; Scholten, J G F; van Kampen, A; Veth, R P H; Verdonschot, N

    2005-05-01

    The objective of this study was to validate an in vitro human cadaver knee-joint model for the evaluation of the meniscal movement during knee-joint flexion. The question was whether our model showed comparable meniscal displacements to those found in earlier meniscal movement studies in vivo. Furthermore, we determined the influence of tibial torque on the meniscal displacement during knee-joint flexion. Three tantalum beads were inserted in the medial meniscus of six human-cadaver joints. The knee joints were placed and loaded in a loading apparatus, and the movements of the beads were determined by means of RSA during knee-joint flexion and extension with and without internal tibial (IT) and external tibial (ET) torque. During flexion without tibial torque, all menisci moved in posterior and lateral direction. The anterior horn showed significantly greater excursions than the posterior horn in both posterior and lateral direction. Internal tibial torque caused an anterior displacement of the pathway on the tibial plateau. External tibial torque caused a posterior displacement of the pathway. External tibial torque restricted the meniscal displacement during the first 30 degrees of knee-joint flexion. The displacements of the meniscus in this experiment were similar to the displacements described in the in vivo MRI studies. Furthermore, the application of tibial torque confirmed the relative immobility of the posterior horn of the meniscus. During external tibial torque, the posterior displacement of the pathway on the tibial plateau during the first 30 degrees of flexion might be restricted by the attached knee-joint capsule or the femoral condyle. This model revealed representative meniscal displacements during simple knee-joint flexion and also during the outer limits of passive knee-joint motion.

  11. Detection of Rsa Ⅰ gene polimorphism of low density lipoprotein receptor related protein and its influence on serum lipid level in hemodialysis patients%血液透析患者低密度脂蛋白受体相关蛋白Rsa Ⅰ位点基因多态性对血脂水平的影响

    Institute of Scientific and Technical Information of China (English)

    王玉新; 张以勤; 叶婧; 陆元善; 徐琴君; 邹和群

    2012-01-01

    Objectives To investigate the characteristics of dislipidemia and influence by low density lipoprotein receptor related protein (LRP) exon 3 Rsa Ⅰ gene polymorphism in hemodialysis patients.Methods serum total cholesterol (TC),triglyceride (TG),low density lipoprotein cholesterol (LDLC),high density lipoprotein cholesterol ( HDLC),apolipoproteins ( Apo A1,B,E) and lipoprotein (a) [Lp (a)] were measured,polymerase chain reaction - restriction fragment length polymophism ( PCR - RFLP) was used to detect LRP gene polymorphism in hemodialysis patients.Results The serum levels of TG and ApoB were higher significantly in the hemodialysis patients compared to contrals,and the levels of TC,LDLC,HDLC were lower compared to controls.Patients with cardiovascular disorder had higher TG level compared to patients without the disorder.The data of LRP polymorphism detected by PCR - RFLP showed that the allele frequency and the distribution of the LRP genotype of tetranucleotide reapeat sequence and exon 3 did not differ significantly between controls and hemodialysis patients.There was no statistic difference in serum lipid level between hemodialysis patients with different genotype of LRP exon 3.Conclusions Hemodialysis patients were liable to develop hypertrglyeridemia and hypocholesteroldemia.TG level might related to the development of cardiovascular disorder in hemodialysis patients.There is different influence of LRP Rsa Ⅰ gene polymorphism on lipid levels between controls and hemodialysis patients.%目的 探讨血液透析患者脂代谢紊乱的临床特征及低密度脂蛋白受体相关蛋白(LRP)外显子3RsaⅠ位点基因多态性对脂代谢的影响.方法 生化方法检测血液透析患者血清总胆固醇(TC)、甘油三酯(TG)、高密度脂蛋白胆固醇(HDLC)、低密度脂蛋白胆固醇(LDLC)、载脂蛋白(Apo)A1、ApoB、ApoE及脂蛋白(Lp)(a)水平,多聚合酶链反应-限制性片断长度多态性方法( PCR - RFLP)检测LRP外显子3Rsa

  12. Mixed Ability Teaching.

    Science.gov (United States)

    Skov, Poul

    1986-01-01

    As a basis for taking a position on the future school structure in grades 8-10 in Denmark, an extensive study was carried out on mixed ability teaching (teaching in heterogeneous classes) on these grade levels. Results showed that mixed ability teaching gave at least as good results as teaching in differentiated classes. (Author/LMO)

  13. Fairness and Ability Grouping.

    Science.gov (United States)

    Strike, Kenneth A.

    1983-01-01

    A recent controversy regarding ability grouping is that it is often perceived as a means whereby racial or class bias can be subtly transformed into mechanisms of discrimination which exhibit the appearance of fairness and objectivity. This article addresses the question of fairness in ability grouping. (CJB)

  14. Measuring Creative Imagery Abilities

    Directory of Open Access Journals (Sweden)

    Dorota M. Jankowska

    2015-10-01

    Full Text Available Over the decades, creativity and imagination research developed in parallel, but they surprisingly rarely intersected. This paper introduces a new theoretical model of creative imagination, which bridges creativity and imagination research, as well as presents a new psychometric instrument, called the Test of Creative Imagery Abilities (TCIA, developed to measure creative imagery abilities understood in accordance with this model. Creative imagination is understood as constituted by three interrelated components: vividness (the ability to create images characterized by a high level of complexity and detail, originality (the ability to produce unique imagery, and transformativeness (the ability to control imagery. TCIA enables valid and reliable measurement of these three groups of abilities, yielding the general score of imagery abilities and at the same time making profile analysis possible. We present the results of eight studies on a total sample of more than 1,700 participants, showing the factor structure of TCIA using confirmatory factor analysis, as well as provide data confirming this instrument’s validity and reliability. The availability of TCIA for interested researchers may result in new insights and possibilities of integrating the fields of creativity and imagination science.

  15. Girls underestimate maths ability

    Science.gov (United States)

    2017-05-01

    A study by psychologists in the US has found that high-school girls rate their competence in mathematics lower than boys, even for those with similar abilities (Front. Psychol. 10.3389/fpsyg.2017.00386).

  16. Mobile Banking Short Message BCH - NAF - RSA Fast Compilation and Encryption and Security Implementation%手机银行短信息的BCH-NAF-RSA快速编译与加密及其安全实现

    Institute of Scientific and Technical Information of China (English)

    邓从政

    2015-01-01

    The rapid spread of the mobile communication technology promotes the communication operators continue to develop new value-added business such as mobile phone banking to increase profits. These operations are often completed by fast compiled code through the short message center. This paper improved traditional binary multiplication algorithm, and presents an optimized low storage NAF point compression multiplication algorithm. It greatly reduces the running time of point multiplication operation, and saves storage space. Here introduces an optimization of BCH iterative decoding algorithm for the design and realization of mobile phone short message paging decoder. The error rate of this decoder algorithm is small. That can greatly enhance the error correcting ability, and improve the quality of short message sending. Through twice compilation of NAF and BCH, it can use conic curve cryptography to encrypt fastly. The velocity of mobile phone SMS paging signal outgoing and incoming will get greatly improved. It can make sure the safety of mobile phone short message bank business transactions and implementation speed.%智能手机的快速普及推动着通信运营商不断开发新的诸如手机银行类的增值业务以增长利润, 这些业务往往通过短信中心来完成. 为了安全快速的实现这些业务, 这里改进了信号发射台短信息的编译码算法, 引入一种优化的 BCH 迭代译码算法, 来设计和实现手机短信寻呼台译码器, 这种译码算法错码率较小, 能大大增强纠错能力, 提高了短信的发送质量. 同时对短信息的加密和解密算法进行了优化, 提出了一种优化的低存储NAF点压缩数乘算法, 大大地缩短了点乘运算的运行时间, 节约了存储空间, 经过 NAF 和 BCH 快速编译后, 利用安全性较高的基于圆锥曲线的 RSA 公钥密码来进行加密, 以提高手机短信寻呼台信号呼出和呼入的速度及其安全性, 保证了手机银行短

  17. Proactive Threshold RSA Signature Scheme Based on Polynomial Secret Sharing%基于多项式秘密共享的前摄性门限RSA签名方案

    Institute of Scientific and Technical Information of China (English)

    徐甫

    2016-01-01

    现有可证明安全的前摄性门限RSA签名方案均依赖加性秘密共享方法,存在每次签名均需所有成员参与,易暴露合法成员的秘密份额,签名效率低下等问题。该文以Shoup门限签名为基础,提出一种基于多项式秘密共享的前摄性门限RSA签名方案,并对其进行了详细的安全性及实用性分析。结果表明,在静态移动攻击者模型中,该方案是不可伪造的和稳健的,与现有同类方案相比,其通信开销更低,运算效率更高。%All the existing provable secure proactive threshold RSA signature schemes rely on additive secret sharing, in which all players have to cooperate to produce a signature, valid players’ secret shares may be exposed, and the computing efficiency is too low. Based on Shoup’s threshold RSA signature scheme, a proactive threshold RSA signature scheme is proposed by using polynomial secret sharing, and its security and practicability are analyzed. Results show that the proposed scheme is unforgeable and robust under the model of static mobile adversary, and compared with the existing comparable schemes, its communication overhead is lower and computing efficiency is higher.

  18. Detección de Anomalías en Oráculos Criptográficos tipo RSA por medio de análisis probabilísticas y estadísticos

    OpenAIRE

    2013-01-01

    Esta línea de investigación persigue la elaboración de herramientas matemáticas susceptibles de ser sistematizadas en un software capaz de detectar anomalías y mal funcionamiento en servicios de infraestructura de clave pública (PKI) que utilicen el esquema RSA. Esta herramienta se puede aplicar en redes Públicas o Privados, Lan´s, o Wan´s e incluso Internet; en sistemas militares como del ámbito civil. Dada la complejidad de los sistemas actuales, se hace cada vez más complicada la det...

  19. Design and realization of anti-addiction mobile software based on RSA algorithm%基于RSA加密算法的防沉迷手机软件设计与实现

    Institute of Scientific and Technical Information of China (English)

    陈璐; 吴鹏; 张锦祥; 方美玉

    2016-01-01

    以Android系统为平台,设计开发了一个青少年防沉迷手机软件.采用了RSA (Rivest-Shamir-Adleman)非对称密钥算法以增加登入验证的破解难度,并对娱乐软件和上网总时间加以防沉迷管理.该软件主要包括软件前台、软件后台、RSA验证和防沉迷管理等模块.

  20. Development of arithmetical abilities

    Directory of Open Access Journals (Sweden)

    Tatjana Levstek

    2014-02-01

    Full Text Available Arithmetic (from the word 'arithmos' which means 'numbers' is an elementary branch of mathematics. Numeracy is essential for understanding mathematics, so the development of arithmetic abilities has been an area of scientific research for a long time. Recent research has shown that the development of arithmetic abilities is not based only on gaining experience and learning. Some arithmetic abilities, especially the sense of quantity, are innate. Even babies are able to distinguish between groups with different number of elements and they perceive numeracy amodally. Six-month-olds distinguish between two groups with the numeracy ratio of 1 : 2. With age this ratio improves rapidly. Five-year-old children already distinguish between groups with the number ratio 7 : 8. The ability to compare two quantities begins to develop after 15 months of age and children learn how to count spontaneously, together with the acquisition of language. Speech enables children to understand number in its abstract, symbolic sense, thus opening the way to symbolic arithmetic. During the preschool period children use intuition when doing calculations, but in school the arithmetic is based on the knowledge of arithmetical algorithms. So, in order to acquire mathematical knowledge, it is necessary to incorporate memory and automate arithmetical processes, without the use of intuition. However, research has shown that intuition is very important and is even a predictive factor for the development of mathematical abilities throughout the schooling process.

  1. Priming Ability Emotional Intelligence

    Science.gov (United States)

    Schutte, Nicola S.; Malouff, John M.

    2012-01-01

    Two studies examined whether priming self-schemas relating to successful emotional competency results in better emotional intelligence performance. In the first study participants were randomly assigned to a successful emotional competency self-schema prime condition or a control condition and then completed an ability measure of emotional…

  2. Priming Ability Emotional Intelligence

    Science.gov (United States)

    Schutte, Nicola S.; Malouff, John M.

    2012-01-01

    Two studies examined whether priming self-schemas relating to successful emotional competency results in better emotional intelligence performance. In the first study participants were randomly assigned to a successful emotional competency self-schema prime condition or a control condition and then completed an ability measure of emotional…

  3. DIFFERENTIAL COGNITIVE ABILITIES.

    Science.gov (United States)

    MACCOBY, ELEANOR E.; RAU, LUCY

    THE RELATIONSHIP OF PATTERNS OF COGNITIVE PROCESSES AND PERSONALITY TRAITS WERE INVESTIGATED IN THIS STUDY OF 6 GROUPS OF CHILDREN (120) IN GRADE 5. SCORES ON THE PRIMARY MENTAL ABILITIES TEST, IOWA ACHIEVEMENT TEST, AND CALIFORNIA TEST OF MENTAL MATURITY WERE USED AS MEASURES OF COGNITIVE PROCESSES. (JK)

  4. Synchronization of Mental Abilities

    NARCIS (Netherlands)

    Guney, A.

    2008-01-01

    I think it is better to summarize some cognitive issues in relation to this subject; how we learn, how we should organize learning (instructions), knowledge, etc. before treating creativity and rationality. Is it, really, possible to consider creativity without any kind of involvement of the ability

  5. A2 Milk Enhances Dynamic Muscle Function Following Repeated Sprint Exercise, a Possible Ergogenic Aid for A1-Protein Intolerant Athletes?

    Science.gov (United States)

    Kirk, Ben; Mitchell, Jade; Jackson, Matthew; Amirabdollahian, Farzad; Alizadehkhaiyat, Omid; Clifford, Tom

    2017-01-01

    Hyperaminoacidemia following ingestion of cows-milk may stimulate muscle anabolism and attenuate exercise-induced muscle damage (EIMD). However, as dairy-intolerant athletes do not obtain the reported benefits from milk-based products, A2 milk may offer a suitable alternative as it lacks the A1-protein. This study aimed to determine the effect of A2 milk on recovery from a sports-specific muscle damage model. Twenty-one male team sport players were allocated to three independent groups: A2 milk (n = 7), regular milk (n = 7), and placebo (PLA) (n = 7). Immediately following muscle-damaging exercise, participants consumed either A2 milk, regular milk or PLA (500 mL each). Visual analogue scale (muscle soreness), maximal voluntary isometric contraction (MVIC), countermovement jump (CMJ) and 20-m sprint were measured prior to and 24, 48, and 72 h post EIMD. At 48 h post-EIMD, CMJ and 20-m sprint recovered quicker in A2 (33.4 ± 6.6 and 3.3 ± 0.1, respectively) and regular milk (33.1 ± 7.1 and 3.3 ± 0.3, respectively) vs. PLA (29.2 ± 3.6 and 3.6 ± 0.3, respectively) (p < 0.05). Relative to baseline, decrements in 48 h CMJ and 20-m sprint were minimised in A2 (by 7.2 and 5.1%, respectively) and regular milk (by 6.3 and 5.2%, respectively) vs. PLA. There was a trend for milk treatments to attenuate decrements in MVIC, however statistical significance was not reached (p = 0.069). Milk treatments had no apparent effect on muscle soreness (p = 0.152). Following muscle-damaging exercise, ingestion of 500 mL of A2 or regular milk can limit decrements in dynamic muscle function in male athletes, thus hastening recovery and improving subsequent performance. The findings propose A2 milk as an ergogenic aid following EIMD, and may offer an alternative to athletes intolerant to the A1 protein. PMID:28134840

  6. Markers for Routine Assessment of Fatigue and Recovery in Male and Female Team Sport Athletes during High-Intensity Interval Training

    Science.gov (United States)

    Wiewelhove, Thimo; Raeder, Christian; Meyer, Tim; Kellmann, Michael; Pfeiffer, Mark; Ferrauti, Alexander

    2015-01-01

    Aim Our study aimed to investigate changes of different markers for routine assessment of fatigue and recovery in response to high-intensity interval training (HIIT). Methods 22 well-trained male and female team sport athletes (age, 23.0 ± 2.7 years; V̇O2max, 57.6 ± 8.6 mL·min·kg−1) participated in a six-day running-based HIIT-microcycle with a total of eleven HIIT sessions. Repeated sprint ability (RSA; criterion measure of fatigue and recovery), countermovement jump (CMJ) height, jump efficiency in a multiple rebound jump test (MRJ), 20-m sprint performance, muscle contractile properties, serum concentrations of creatinkinase (CK), c-reactive protein (CRP) and urea as well as perceived muscle soreness (DOMS) were measured pre and post the training program as well as after 72 h of recovery. Results Following the microcycle significant changes (p HIIT induced fatigue and subsequent recovery. However, low accuracy of a single or combined use of these markers requires the verification of their applicability on an individual basis. PMID:26444557

  7. Music and nonmusical abilities.

    Science.gov (United States)

    Schellenberg, E G

    2001-06-01

    Reports that exposure to music causes benefits in nonmusical domains have received widespread attention in the mainstream media. Such reports have also influenced public policy. The so-called "Mozart effect" actually refers to two relatively distinct phenomena. One concerns short-term increases in spatial abilities that are said to occur from listening to music composed by Mozart. The other refers to the possibility that formal training in music yields nonmusical benefits. A review of the relevant findings indicates that the short-term effect is small and unreliable. Moreover, when it is evident, it can be explained by between-condition differences in the listener's mood or levels of cognitive arousal. By contrast, the effect of music lessons on nonmusical aspects of cognitive development is still an open question. Several studies have reported positive associations between formal music lessons and abilities in nonmusical (e.g., linguistic, mathematical, and spatial) domains. Nonetheless, compelling evidence for a causal link remains elusive.

  8. Correlation analysis of family function, coping style and mental health of RSA patients%复发性流产患者家庭功能及应对方式与心理状况分析

    Institute of Scientific and Technical Information of China (English)

    曾晓琴; 肖青; 龚桂芳

    2014-01-01

    Objective To explore the relationship between family function and coping style of recurrent spontaneous abortion ( RSA) women and mental health.Methods Totally 150 RSA patients and 150 ordinary women were selected in patient group and control group , respectively.Family Assessment Device (FAD), Medical Coping Mode Questionnaire and Symptom Check List-90 (SCL-90) were used to evaluate the relationship among them .Results Compared with the control group , the patient group had higher average score and total score on SCL-90 (both P<0.05), and the scores on “solving problem”,“communication”,“role”,“behavior control” and“general features”in FAD were obviously lower (t value was 3.58, 2.81, 2.45, 2.16 and 2.81, respectively, all P<0.05).RSA patients were more inclined to adopt a “yield” negative coping style ( t =3.08, P <0.01).SCL-90 scores and FAD scores of RSA patients showed a significant positive correlation (P<0.05).There was significant negative correlation between factors of family function and coping style of“yield”(r value was -0.12, -0.12, -0.12, -0.11, -0.14, -0.13 and -0.12, respectively, all P<0.05).Multiple regression analysis showed that the marital relationship and the frequency of natural abortion were major factors affecting the mental health of RSA patients.Conclusion RSA women has poor mental health , and we should help them to establish a correct perception and positive coping style.Clinical diagnosis and treatment combining active sustained and individual care with comprehensive intervention should be provided for them and focus on family intervention , so as to improve psychological health of RSA patients .%目的:探讨复发性流产( RSA)患者家庭功能、个人应对方式及心理健康之间的关系。方法选取复发性流产患者及普通妇女各115例作为病例组及对照组,采用家庭功能评定量表、医学应对方式问卷及症状自评量表( SCL-90)进行调查,分析三者

  9. General English Ability, Specific Purpose English Ability, and Computer Skills.

    Science.gov (United States)

    Prapphal, Kanchana

    2003-01-01

    Aims to answer the following research questions: (1) Are general English ability and specific purpose English ability related to computer skills? and (2) Is general English ability transferable to specific purpose English ability? Subjects were third year science students enrolled in an English for academic purposes course. (Author/VWL)

  10. Former for ability

    DEFF Research Database (Denmark)

    Andersen, Maja Lundemark

    Resume FORMER FOR ABILITY Hvilke betydninger tillægges en ADHD-diagnose i forhold til selvforståelse,intersubjektive og institutionelle positioner? Med denne afhandling har jeg ønsket at synliggøre, hvordan voksne med ADHD selv skaber mening med diagnosen, og hvilke betydninger og anvendelsesmuli......Resume FORMER FOR ABILITY Hvilke betydninger tillægges en ADHD-diagnose i forhold til selvforståelse,intersubjektive og institutionelle positioner? Med denne afhandling har jeg ønsket at synliggøre, hvordan voksne med ADHD selv skaber mening med diagnosen, og hvilke betydninger og......, de kan. ADHD anvendes som kategori, men i en kompleks betydning, hvor ADHD som diagnose anvendes som overskrift, men indholdet defineres og beskrives af respondenterne selv. ADHD anvendes subjektivt med forskellig betydning i komplekse mønstre, der inddrager såvel alder, køn som social forankring...... adfærdsregulering og skaber basis for indlæring af ritualer, der fungerer som sociale dørtrin i enhver social samhandling. Samtidig fastholder respondenterne dog krav til omgivelserne om hensyn og særlige kommunikationsformer. Jeg konkluderer, at medicin ikke fjerner symptomerne, men til en vis grad dæmper dem, og...

  11. Rest interval duration does not influence adaptations in acid/base transport proteins following 10 wk of sprint-interval training in active women.

    Science.gov (United States)

    McGinley, Cian; Bishop, David J

    2017-05-01

    The removal of protons (H(+)) produced during intense exercise is important for skeletal muscle function, yet it remains unclear how best to structure exercise training to improve muscle pH regulation. We investigated whether 4 wk of work-matched sprint-interval trining (SIT), performed 3 days/wk, with either 1 (Rest-1; n = 7) or 5 (Rest-5; n = 7) min of rest between sprints, influenced adaptations in acid/base transport protein content, nonbicarbonate muscle buffer capacity (βmin vitro), and exercise capacity in active women. Following 1 wk of posttesting, comprising a biopsy, a repeated-sprint ability (RSA) test, and a graded-exercise test, maintenance of adaptations was then studied by reducing SIT volume to 1 day/wk for a further 5 wk. After 4 wk of SIT, there was increased protein abundance of monocarboxylate transporter (MCT)-1, sodium/hydrogen exchanger (NHE)-1, and carbonic anhydrase (CA) XIV for both groups, but rest interval duration did not influence the adaptive response. In contrast, greater improvements in total work performed during the RSA test after 4 wk of SIT were evident for Rest-5 compared with Rest-1 (effect size: 0.51; 90% confidence limits ±0.37), whereas both groups had similarly modest improvements in V̇o2peak When training volume was reduced to 1 day/wk, enhanced acid/base transport protein abundance was maintained, although NHE1 content increased further for Rest-5 only. Finally, our data support intracellular lactate as a signaling molecule for inducing MCT1 expression, but neither lactate nor H(+) accumulation appears to be important signaling factors in MCT4 regulation. Copyright © 2017 the American Physiological Society.

  12. Effect of Small-Sided Games and Repeated Shuffle Sprint Training on Physical Performance in Elite Handball Players.

    Science.gov (United States)

    Dello Iacono, Antonio; Ardigò, Luca P; Meckel, Yoav; Padulo, Johnny

    2016-03-01

    This study was designed to compare the effects of small-sided games (SSGs) and repeated shuffle sprint (RSS) training on repeated sprint ability (RSA) and countermovement jump (CMJ) tests performances of elite handball players. Eighteen highly trained players (24.8 ± 4.4 years) were assigned to either SSG or RSS group training protocols twice a week for 8 weeks. The SSG training consisted of 5 small-sided handball games with 3-a-side teams excluding goalkeepers. The RSS consisted of 2 sets of 14-17 of 20-m shuttle sprints and 9-m jump shots interspersed by 20-second recoveries. Before and after training, the following performance variables were assessed: speed on 10-m and 20-m sprint time, agility and RSA time, CMJ height, standing throw, and jump shot speed. Significant pre-to-post treatment improvements were found in all the assessed variables following both training protocols (multivariate analysis of variance, p ≤ 0.05). There was a significantly greater improvement on 10-m sprint, CMJ, and jump shooting, after the RSS in comparison with SSG training (+4.4% vs. +2.4%, +8.6% vs. +5.6%, and +5.5% vs. +2.7%, respectively). Conversely, agility and standing throwing showed lower improvements after RSS in comparison with SSG (+1.0% vs. +7.8% and +1.6% vs. +9.0%, respectively). These results indicate that these training methods are effective for fitness development among elite adult handball players during the last period of the competitive season. Specifically, SSG seems to be more effective in improving agility and standing throw, whereas RSS seems preferable in improving 10-m sprint, CMJ, and jump shot.

  13. Effect of Recipe of Supplementing Qi and Activating Blood (RSA) on NO3-、ONOO-、MDA、GLU、AMY in Faeces of High Fat Diet Rats%补气活血法对高脂饮食大鼠粪便NO-3 、ONOO- 、MDA、GLU、AMY的影响

    Institute of Scientific and Technical Information of China (English)

    马月梅; 刘晓秋; 张永斌

    2011-01-01

    Objective To investigate the effect of high fat diet on NO3-、 ONOO - ,MDA,glucose,amylase activity. PNA,PSA binding rates af amylase, amylase isoenzyme profile in rat faeces and the effect of recipe of supplementing Qi and activating blood ( RSA )Methods Male rats were randomly divided into four groups: normal group( feeding ordinary diet) ; model group( feeding high fat diet) ;RSA Ⅰ ( feeding RSAI ( S: A =2: 1) by gastrogavage) ; RSA 2 ( feeding RSA2 ( S: A = 1 : 2) by gastrogavage) . N03- , ONOO- , MDA , glucose and amylase activity in rat faeces were determined by colorimetric method. N -glycan patterns of amylase were determined with lectin ( PSA and PNA) affinity precipitation method, and faeces amylase isoenzyme profile was separated by electrophoresis on polyacrylamide gels electrophoresis ( PAGE). Results High fat diet rats showed the symptoms of polyuria, polydipsia, polyphagia and weight loss. These abnormal signs were improved after treatment with RSA. In high fat diet rats, amylase activity, N03 - , P - Amy.S - Amy in faeces were decreased, while PSA, PNA binding rates of amylase, glucose, ONOO - in faeces were increased. After treatment with RSA, all of these indicators were improved. There was difference between RSA1 action and RSA 2 action. Conclusion Supplementing Qi and activating blood method can improve N - glycan deficiency in faeces amylase and up - regulate faeces amylase activity , and increase N03- , also decrease glucose, ONOO- in faeces, thus can regulate the digestion/absorption and glucose metabolism, can reduce oxygen free radicalinduced intestinal damage. This study also showed the different impacts of two different RSA.%目的 研究高脂饮食对大鼠粪便NO3-、ONOO-、MDA、GLU、AMY活性、AMY PSA、PNA结合率、AMY谱的影响,同时研究补气活血中药的作用.方法 雄性SD大鼠随机分为正常组,喂饲普通饲料;模型组,喂饲高脂饲料;补气活血1组(RSA 1),2∶ 1补气

  14. The Effect of Two Speed Endurance Training Regimes on Performance of Soccer Players.

    Directory of Open Access Journals (Sweden)

    F Marcello Iaia

    Full Text Available In order to better understand the specificity of training adaptations, we compared the effects of two different anaerobic training regimes on various types of soccer-related exercise performances. During the last 3 weeks of the competitive season, thirteen young male professional soccer players (age 18.5±1 yr, height 179.5±6.5 cm, body mass 74.3±6.5 kg reduced the training volume by ~20% and replaced their habitual fitness conditioning work with either speed endurance production (SEP; n = 6 or speed endurance maintenance (SEM; n = 7 training, three times per wk. SEP training consisted of 6-8 reps of 20-s all-out running bouts followed by 2 min of passive recovery, whereas SEM training was characterized by 6-8 x 20-s all-out efforts interspersed with 40 s of passive recovery. SEP training reduced (p<0.01 the total time in a repeated sprint ability test (RSAt by 2.5%. SEM training improved the 200-m sprint performance (from 26.59±0.70 to 26.02±0.62 s, p<0.01 and had a likely beneficial impact on the percentage decrement score of the RSA test (from 4.07±1.28 to 3.55±1.01% but induced a very likely impairment in RSAt (from 83.81±2.37 to 84.65±2.27 s. The distance covered in the Yo-Yo Intermittent Recovery test level 2 was 10.1% (p<0.001 and 3.8% (p<0.05 higher after SEP and SEM training, respectively, with possibly greater improvements following SEP compared to SEM. No differences were observed in the 20- and 40-m sprint performances. In conclusion, these two training strategies target different determinants of soccer-related physical performance. SEP improved repeated sprint and high-intensity intermittent exercise performance, whereas SEM increased muscles' ability to maximize fatigue tolerance and maintain speed development during both repeated all-out and continuous short-duration maximal exercises. These results provide new insight into the precise nature of a stimulus necessary to improve specific types of athletic performance in

  15. Continuous distal migration and internal rotation of the C-stem prosthesis without any adverse clinical effects: an RSA study of 33 primary total hip arthroplasties followed for up to ten years.

    Science.gov (United States)

    von Schewelov, T; Carlsson, A; Sanzén, L; Besjakov, J

    2014-05-01

    In 2005, we demonstrated that the polished triple-tapered C-stem at two years had migrated distally and rotated internally. From that series, 33 patients have now been followed radiologically, clinically and by radiostereometric analysis (RSA) for up to ten years. The distal migration within the cement mantle had continued and reached a mean of 2 mm (0.5 to 4.0) at ten years. Internal rotation, also within the cement mantle, was a mean 3.8° (external 1.6° to internal 6.6°) The cement mantle did not show any sign of migration or loosening in relation to the femoral bone. There were no clinical or radiological signs indicating that the migration or rotation within the cement mantle had had any adverse effects for the patients.

  16. Stability assessment of a moderately conforming all-polyethylene tibial component in total knee arthroplasty: a prospective RSA study with 2 years of follow-up of the Kinemax Plus design.

    Science.gov (United States)

    Adalberth, G; Nilsson, K G; Byström, S; Kolstad, K; Mallmin, H; Milbrink, J

    1999-01-01

    The magnitude and pattern of the migration of an all-polyethylene tibial component with moderately conforming articular surfaces in total knee arthroplasty was analyzed in 20 patients > or =60 years during a 2-year follow-up using radiostereometry (RSA). Most of the migration occurred during the initial 4 months, whereafter the migration diminished, reaching a mean maximum migration of 0.75 mm at 2 years. Similar patterns were found for rotation of the implant. Maximum subsidence at 2 years was 0.7 mm and was most commonly located at the posteromedial part of the tibial component. These results indicate that an all-polyethylene tibial component with moderately conforming articular geometry and with a thickness of 10-12 mm demonstrated migration patterns compatible with a favorable prognosis in regard to future aseptic loosening.

  17. 二维码加密的手机签到系统设计%The Design of Mobile Check-in System Based on RSA and QR Code Encryption

    Institute of Scientific and Technical Information of China (English)

    曹记东; 和斌涛

    2016-01-01

    This mobile check-in system can realize notice, check, records and query four functions. Based on RSA and QR code encryption technology, at the same time, considering time ,area and identity when using QR code sign in which can effectively prevent the long-distance scanning and the check by other.%文章设计的手机签到系统集会议通知、会议签到、记录报表、记录查询四大功能于一身。基于RSA和二维码加密技术,同时在利用二维码扫码签到时合理地考虑了扫码时间、扫码地址、扫码身份识别等因素,可以有效地防止异地扫描和现场代签等情况。

  18. Road Safety Audit RSA : best practice guidelines, qualification for auditors and 'programming'. Deliverable D4 of the RiPCORD-iSEREST project (Road Infrastructure Safety Protection - Core-Research and Development for Road Safety in Europe; Increasing safety and reliability of secondary roads for a sustainable Surface Transport).

    NARCIS (Netherlands)

    Matena, S. Weber, R. Huber, C.A. Hruby, Z. Pokorny, P. Gaitanidou, E. Vaneerdewegh, P. Strnad, B. Cardoso, J. Schermers, G. & Elvik, R.

    2009-01-01

    This report contains 'best practice' guidelines for road safety audits (RSA) and summarises practices which have been successfully applied in European countries or abroad. The goals of this report are to inform the reader on the reasons why carrying out audits is beneficial and how to successfully c

  19. Road Safety Audit RSA : best practice guidelines, qualification for auditors and 'programming'. Deliverable D4 of the RiPCORD-iSEREST project (Road Infrastructure Safety Protection - Core-Research and Development for Road Safety in Europe; Increasing safety and reliability of secondary roads for a sustainable Surface Transport).

    NARCIS (Netherlands)

    Matena, S. Weber, R. Huber, C.A. Hruby, Z. Pokorny, P. Gaitanidou, E. Vaneerdewegh, P. Strnad, B. Cardoso, J. Schermers, G. & Elvik, R.

    2009-01-01

    This report contains 'best practice' guidelines for road safety audits (RSA) and summarises practices which have been successfully applied in European countries or abroad. The goals of this report are to inform the reader on the reasons why carrying out audits is beneficial and how to successfully

  20. Road Safety Audit RSA : best practice guidelines, qualification for auditors and 'programming'. Deliverable D4 of the RiPCORD-iSEREST project (Road Infrastructure Safety Protection - Core-Research and Development for Road Safety in Europe; Increasing safety and reliability of secondary roads for a sustainable Surface Transport).

    NARCIS (Netherlands)

    Matena, S. Weber, R. Huber, C.A. Hruby, Z. Pokorny, P. Gaitanidou, E. Vaneerdewegh, P. Strnad, B. Cardoso, J. Schermers, G. & Elvik, R.

    2009-01-01

    This report contains 'best practice' guidelines for road safety audits (RSA) and summarises practices which have been successfully applied in European countries or abroad. The goals of this report are to inform the reader on the reasons why carrying out audits is beneficial and how to successfully c

  1. Shuttle-Run Sprint Training in Hypoxia for Youth Elite Soccer Players: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Hannes Gatterer

    2014-12-01

    Full Text Available The purposes of the present study were to investigate if a shuttle-run sprint training performed in a normobaric hypoxia chamber of limited size (4.75x2.25m is feasible, in terms of producing the same absolute training load, when compared to training in normoxia, and b if such training improves the repeated sprint ability (RSA and the Yo-Yo intermittent recovery (YYIR test outcome in young elite soccer players. Players of an elite soccer training Centre (age: 15.3 ± 0.5 years, height: 1.73 ± 0.07 m, body mass: 62.6 ± 6.6 kg were randomly assigned to a hypoxia or a normoxia training group. Within a 5-week period, players, who were not informed about the hypoxia intervention, performed at least 7 sessions of identical shuttle-run sprint training either in a normal training room (FiO2 = 20.95% or in a hypoxic chamber (FiO2 = 14.8%; approximately 3300m, both equipped with the same floor. Each training session comprised 3 series of 5x10s back and forth sprints (4.5m performed at maximal intensity. Recovery time between repetitions was 20s and between series 5min. Before and after the training period the RSA (6 x 40m shuttle sprint with 20 s rest between shuttles and the YYIR test were performed. The size of the chamber did not restrict the training intensity of the sprint training (both groups performed approximately 8 shuttles during 10s. Training in hypoxia resulted in a lower fatigue slope which indicates better running speed maintenance during the RSA test (p = 0.024. YYIR performance increased over time (p = 0.045 without differences between groups (p > 0.05. This study showed that training intensity of the shuttle-run sprint training was not restricted in a hypoxic chamber of limited size which indicates that such training is feasible. Furthermore, hypoxia compared to normoxia training reduced the fatigue slope during the RSA test in youth soccer players.

  2. Preseason Training: The Effects of a 17-Day High-Intensity Shock Microcycle in Elite Tennis Players

    Science.gov (United States)

    Fernandez-Fernandez, Jaime; Sanz-Rivas, David; Sarabia, Jose Manuel; Moya, Manuel

    2015-01-01

    Preseasons in tennis are normally reduced to 5 to 7 weeks duration, and coaches should use an integrated approach to conditioning and skill-based work. The aim of the present study was to investigate the effects of adding a high-intensity training (HIT) shock microcycle to the normal training content in several physical performance indicators in the preseason training of high-level male tennis players. Over 17 days, 12 male tennis players performed 13 HIT sessions in addition to their usual training. Physical performance tests (30:15 intermittent fitness test [VIFT], 20 m sprint, countermovement jump [CMJ], repeated sprint ability [RSA]) were conducted before (pre-test) and 5 days after the intervention (post-test). After the shock microcycle, results showed a significant increase in the VIFT (p < 0.001; Large ES) and a significant decrease in the mean RSA time (RSAm) (p = 0.002; Small ES), while there were no significant changes in the other parameters analysed (e.g., 20 m, CMJ, best RSA time [RSAb]; percentage of decrement in the RSA [%Dec]). Moreover, the training load (TL) during tennis sessions was significantly higher (p < 0.01; Large ES) than the TL during the integrated sessions, except during the first training session. A 17-day shock microcycle (i.e., 13 HIT sessions) in addition to the regular tennis training significantly improved parameters that can impact physical performance in tennis. Moreover, additional sessions, including running exercises based on the 30:15ITF and on-court specific exercises, were characterised by significantly lower TL than tennis-training sessions. Key points HIT shock microcycle increases performance in professional tennis players in a short period of time. The inclusion of additional sessions, with running exercises based on the 30:15ITF and on-court specific exercises, was characterised by a significantly lower TL than tennis-training sessions alone. Coaches should be aware of TL (e.g., RPE) and fatigue-related parameters

  3. Impact of 6 consecutive days of sprint training in hypoxia on performance in competitive sprint runners.

    Science.gov (United States)

    Kasai, Nobukazu; Mizuno, Sahiro; Ishimoto, Sayuri; Sakamoto, Etsuko; Maruta, Misato; Kurihara, Toshiyuki; Kurosawa, Yuko; Goto, Kazushige

    2017-04-18

    The purpose of the present study was to determine the effects of 6 successive days of repeated sprint training in moderate hypoxia on anaerobic capacity in 100-200-m sprint runners. Eighteen male sprint runners (age, 20.0 ± 0.3 years; height, 175.9 ± 1.1 cm; body mass, 65.0 ± 1.2 kg) performed repeated cycling sprints for 6 consecutive days in either normoxic (NOR; fraction of inspired oxygen [FiO2], 20.9%; n = 9) or hypoxic conditions (HYPO; FiO2, 14.5%; n = 9). The repeated sprint ability (10 × 6-s sprints), 30-s maximal sprint ability, maximal oxygen uptake (VO2max), and 60-m running time on the track were measured before and after the training period. Intramuscular PCr content (quadriceps femoris muscle) was measured by P-magnetic resonance spectroscopy (P-MRS) before and after the training period. Both groups showed similar improvements in repeated sprint ability after the training period (Psprint test and VO2max did not change significantly after the training period in either group. Running time for 0-10m improved significantly after the training period in the HYPO only (before, 1.39 ± 0.01s; after, 1.34 ± 0.02s, Psprint training for 6 consecutive days in hypoxia or normoxia improved repeated sprint ability in competitive sprint runners.

  4. 基于RSA的网关口令认证密钥交换协议的分析与改进%Cryptanalysis and Improvement of Gateway-Oriented Password Authenticated Key Exchange Protocol Based on RSA

    Institute of Scientific and Technical Information of China (English)

    汪定; 王平; 雷鸣

    2015-01-01

    设计安全高效的基于RSA的口令认证密钥交换协议是密码学领域的公开难题.2011年Wei等学者首次提出了一个基于RSA的可证明安全的网关口令认证密钥交换协议,并声称在随机预言模型下基于大整数的素因子分解困难性证明了协议的安全性.利用该协议中服务器端提供的预言机服务,提出一种分离攻击,攻击者只需发起几十次假冒会话便可恢复出用户的口令.攻击结果表明,该协议无法实现所声称的口令保护这一基本安全目标,突出显示了分离攻击是针对基于RSA的口令认证密钥交换协议的一种严重安全威胁.进一步指出了协议形式化安全证明中的失误,给出一个改进方案.分析结果表明,改进方案在提高安全性的同时保持了较高效率,更适于移动通信环境.%It remains an open problem to design a secure and efficient RSA-based password-authenticated key exchange (PAKE )protocol in the areas of cryptography .In 2011 ,Wei proposed the first provably secure gateway-oriented PAKE protocol us-ing RSA ,and claimed that the protocol is provably secure in the random oracle model based on the intractability of the integer fac-torization problem .However ,in this short paper ,we point out that an adversary can launch the separation attack on their protocol by exploiting the oracle service unwittingly provided by the server ,and a user’s password can thus be guessed just after tens of mali-cious sessions .Our cryptanalysis result invalidates Wei’s claim that their protocol can achieve the security goal of password protec-tion ,and highlights the damaging threat that separation attack poses to RSA-based PAKE protocols .Furthermore ,we uncover the flaws in their formal security proof and put forward an enhancement to overcome the identified defect .The analysis results show that the improved protocol eliminates the vulnerability of Wei’s protocol while keeping the

  5. Rational Distributed Computation of the RSA Private Key over the Shared Euler Totient Function%基于欧拉函数秘密分享的RSA私钥的理性分布计算

    Institute of Scientific and Technical Information of China (English)

    李铁牛; 李红达

    2010-01-01

    Along with the distributed computation becoming more and more popular,security mechanisms of the distributed RSA key computation to enhance the strength of distributed authentication and data privacy have been developed quite a lot. However,most of them are the solutions for parties with traditional types like being semi-honest or malicious. We propose a rational approach to dealing with the distributed computation of the RSA private key based on the secret sharing of the Euler totient function over polynomials,in which each player evolved is selfish and motivated to gain interest as mush as possible. The achievement is that it is a Nash equilibrium that each player follows the execution of the prescribed protocol. And the strategy survives the iterated deletion of weakly dominated strategies%随着分布式计算的发展,分布式计算环境中的安全性问题变得越来越突出.基于RSA算法的分布式认证和分布式数据加密等安全性机制也取得了长足的发展.不过,这些机制中大部分是基于传统密码协议中参与者类型的假设:半诚实或恶意的.本文从假设参与者是理性的这一视角出发,设计了基于RSA欧拉函数秘密分享的RSA私钥的分布式计算协议.协议中所有的参与者均是理性的,他们以自我利益为驱动.所有的参与者均采取遵守协议的执行这一策略形成了纳什均衡,并且该策略是不能严格劣势剔除的.

  6. Historical Evolution of Spatial Abilities

    Directory of Open Access Journals (Sweden)

    A. Ardila

    1993-01-01

    Full Text Available Historical evolution and cross-cultural differences in spatial abilities are analyzed. Spatial abilities have been found to be significantly associated with the complexity of geographical conditions and survival demands. Although impaired spatial cognition is found in cases of, exclusively or predominantly, right hemisphere pathology, it is proposed that this asymmetry may depend on the degree of training in spatial abilities. It is further proposed that spatial cognition might have evolved in a parallel way with cultural evolution and environmental demands. Contemporary city humans might be using spatial abilities in some new, conceptual tasks that did not exist in prehistoric times: mathematics, reading, writing, mechanics, music, etc. Cross-cultural analysis of spatial abilities in different human groups, normalization of neuropsychological testing instruments, and clinical observations of spatial ability disturbances in people with different cultural backgrounds and various spatial requirements, are required to construct a neuropsychological theory of brain organization of spatial cognition.

  7. Assessment of English Speaking Ability.

    Science.gov (United States)

    Nakamura, Yuji

    1996-01-01

    The purpose of this research is to examine the detailed components of Japanese students' English speaking ability in terms of communicative competence by using an oral proficiency test based on Bachman's Communicative Language Ability model (included in an appendix). Eighty college students were tested on four tasks--speech making, visual material…

  8. Implicit Learning as an Ability

    Science.gov (United States)

    Kaufman, Scott Barry; DeYoung, Caroline G.; Gray, Jeremy R.; Jimenez, Luis; Brown, Jamie; Mackintosh, Nicholas

    2010-01-01

    The ability to automatically and implicitly detect complex and noisy regularities in the environment is a fundamental aspect of human cognition. Despite considerable interest in implicit processes, few researchers have conceptualized implicit learning as an ability with meaningful individual differences. Instead, various researchers (e.g., Reber,…

  9. The ppuI-rsaL-ppuR quorum-sensing system regulates cellular motility, pectate lyase activity, and virulence in potato opportunistic pathogen Pseudomonas sp. StFLB209.

    Science.gov (United States)

    Kato, Taro; Morohoshi, Tomohiro; Someya, Nobutaka; Ikeda, Tsukasa

    2015-01-01

    Pseudomonas sp. StFLB209 was isolated from potato leaf as an N-acylhomoserine lactone (AHL)-producing bacterium and showed a close phylogenetic relationship with P. cichorii, a known plant pathogen. Although there are no reports of potato disease caused by pseudomonads in Japan, StFLB209 was pathogenic to potato leaf. In this study, we reveal the complete genome sequence of StFLB209, and show that the strain possesses a ppuI-rsaL-ppuR quorum-sensing system, the sequence of which shares a high similarity with that of Pseudomonas putida. Disruption of ppuI results in a loss of AHL production as well as remarkable reduction in motility. StFLB209 possesses strong pectate lyase activity and causes maceration on potato tuber and leaf, which was slightly reduced in the ppuI mutant. These results suggest that the quorum-sensing system is well conserved between StFLB209 and P. putida and that the system is essential for motility, full pectate lyase activity, and virulence in StFLB209.

  10. Ability Dispersion and Team Performance

    DEFF Research Database (Denmark)

    Hoogendoorn, Sander; Parker, Simon C.; Van Praag, Mirjam

    What is the effect of dispersed levels of cognitive ability of members of a (business) team on their team's performance? This paper reports the results of a field experiment in which 573 students in 49 teams start up and manage real companies under identical circumstances for one year. We ensured...... exogenous variation in -otherwise random- team composition by assigning students to teams based on their measured cognitive abilities (Raven test). Each team performs a variety of tasks, often involving complex decision making. The key result of the experiment is that the performance of business teams first...... increases and then decreases with ability dispersion. We seek to understand this finding by developing a model in which team members of different ability levels form sub-teams with other team members with similar ability levels to specialize in different productive tasks. Diversity spreads production over...

  11. Ability Dispersion and Team Performance

    DEFF Research Database (Denmark)

    Hoogendoorn, Sander; Parker, Simon C.; Van Praag, Mirjam

    What is the effect of dispersed levels of cognitive ability of members of a (business) team on their team's performance? This paper reports the results of a field experiment in which 573 students in 49 (student) teams start up and manage real companies under identical circumstances for one year. We...... ensured exogenous variation in otherwise random team composition by assigning students to teams based on their measured cognitive abilities. Each team performs a variety of tasks, often involving complex decision making. The key result of the experiment is that the performance of business teams first...... increases and then decreases with ability dispersion. We seek to understand this finding by developing a model in which team members of different ability levels form sub- teams with other team members with similar ability levels to specialize in different productive tasks. Diversity spreads production over...

  12. Ability Dispersion and Team Performance

    DEFF Research Database (Denmark)

    Hoogendoorn, Sander; Parker, Simon C.; Van Praag, Mirjam

    What is the effect of dispersed levels of cognitive ability of members of a (business) team on their team's performance? This paper reports the results of a field experiment in which 573 students in 49 teams start up and manage real companies under identical circumstances. We ensured exogenous...... variation in - otherwise random - team composition by assigning students to teams based on their measured cognitive abilities (Raven test). Each team performs a variety of tasks, often involving complex decision making. The key result of the experiment is that the performance of business teams first...... increases and then decreases with ability dispersion. We seek to understand this finding by developing a model in which team members of different ability levels form sub-teams with other team members with similar ability levels to specialize in different productive tasks. Diversity spreads production over...

  13. Analyses on the Treatment of Pre-thrombotic State in RSA Patients from the TCM Syndrome of Kidney Deficiency and Blood Stasis%从“肾虚血瘀”论治复发性流产血栓前状态

    Institute of Scientific and Technical Information of China (English)

    谢志燕; 常惠

    2015-01-01

    血栓前状态与复发性流产密切相关,无论从“治未病”,还是从“有故无殒亦无殒也”的理论出发,中医药在防治复发性流产血栓前状态方面的优势不容忽视。%Since recurrent spontaneous abortion (RSA) is strongly associated with the pre-thrombotic state, Chinese medicine in preventing the pre-thrombotic state of RSA should never be neglected according to the TCM theory, such as the theory of " preventive treatment of diseases" and " whether with harsh nature or without, the medicine aiming at diseases can not lead to abortion".

  14. High ability: Giftedness and talent

    Directory of Open Access Journals (Sweden)

    María Dolores Prieto Sánchez

    2010-04-01

    Full Text Available This special issue of the journal aims at putting together national and international research on high abilities, and is divided into three sections: 1 Roles and cognitive, emotional and professional competences of high ability students’ teachers, 2 Identification and assessment of high ability students, 3 Analysis of practices, programs and mentoring of high ability students’ attention to diversity.The articles are authored by scholars from nine different countries (Spain, Argentina, UK, USA, Russia, Brazil, Saudi Arabia, Portugal and Poland, from sixteen different Spanish and international universities: Alicante (Spain, Autónoma de Barcelona (Spain, Málaga (Spain, Murcia (Spain, Navarra (Spain, Oviedo (Spain, Tufts University (USA, Yale University (USA, Moscow State University (Russia, Nacional de La Plata (Argentina, University of Connecticut (USA, Universidade do Minho (Portugal, Universidade da Beira Interior (Portugal, Universidade do Estado do Rio de Janeiro (Brazil, King Faisal University (Saudi Arabia and Universidad de Szczecin (Poland.

  15. The ability of modern secretary

    Institute of Scientific and Technical Information of China (English)

    张诗怡; 张婉玲

    2014-01-01

    Modern secretaries need to master a lot of old and new skills including some required skills and some modern abilities. And secretaries in modern offices also have to master some special skills to be supportive to their bosses.

  16. 基于硬件加密卡技术的RSA加密引擎的局部封装%The local package of RSA encryption engine based on hardware-based encryption card technology

    Institute of Scientific and Technical Information of China (English)

    徐敏

    2011-01-01

    目前主流的VPN是通过SSL协商进行认证的,其在调用Openssl的加密引擎过程中带来一个问题,即进行数据加密所使用的公钥不是自身的密钥,于是加密引擎不仅要有对私钥解密进行硬件实现,还要有对公钥加密实现原有算法调用的技术。本文介绍了目前主流的Openssl实现硬件RSA加密引擎仅对私钥解密数据进行调用,而对于公钥加密数据不调用的局部封装方法,有着重要的实用价值。%VPN is currently the mainstream for certification through the SSL negotiation, the encryption engine in the calling pro- cess Openssl creates a problem. Namely, the public key used to encrypt the data itself is not the key, so not only has a private key encryption engine decrypt the hardware implementation, but also for public key encryption algorithm to achieve the original call technology. This article describes the current mainstream hardware Openssl RSA encryption engine to decrypt the local data encapsulation methods in which private key data calls only, and does not call for public-key encryption. It has important practical value.

  17. Design and Implementation of Android System Short Message Encryption based on 3DES and RSA%基于3DES和RSA的Android系统短信加密设计与实现

    Institute of Scientific and Technical Information of China (English)

    马玉琢; 郭玉翠

    2016-01-01

    Android System, as an open source system, is more and more popular.At the same time, its security and user privacy face a great challenge.This paper puts forward an encryption scheme to protect the privacy of short mes-sage. Starting from the overall architecture and hierarchical idea of Android system, a new encryption scheme based on the hybrid encryption algorithm is proposed in this paper through the analysis and research on the 3DES symmetric encryption algorithm and RSA non symmetric encryption algorithm. The process of realizing algorithmis introduced in detail. The test by using the Android simulator to send and receive the short message proves the feasibility of the short message encryption scheme.%Android系统作为开源的系统,受到越来越多的青睐,同时其安全性及用户的隐私也受到了极大的考验。本文提出了一种针对短信隐私保护的加密方案。从 Android 系统的整体架构及分层思想出发,通过对3DES 对称加密算法及 RSA非对称加密算法的原理进行分析与研究,提出了一种新型的针对 Android系统的混合加密算法的短信加密方案,详细地介绍了具体的实现过程。使用Android模拟器进行的收发仿真实验,证明了短信加密方案的可行性。

  18. 基于RSA的有序多重数字签名在电子病案中的实现%Application of Sequential Multi-signture based Based RSA in Electronic Medical Record

    Institute of Scientific and Technical Information of China (English)

    杨李梅; 杨慧杰; 黄坚; 杨新宇

    2011-01-01

    Objective In order to strengthen information management securit in electronic medical record , and speed up the implem entation of "Electronic Signature Law " in medical and health fields. Methods The application of sequential multi-signature based on RSA in electronic medical record is researched . Results With the help of this application . the safety and reliability of electronic medical record is ensured . Besides. security mechanism could be provided in the process of generating . saving , managing and calling the electronic medical record . Conclusion Technical possibility is provided to make electronic medical record have the same legal effect as paper record . so that legitim ate evidence is available to resolve medical disputes effectively .%目的 为了加强电子病案信息安全管理,加快在医疗卫生领域的落实.方法 初步探讨基于RSA的有序多重数字签名在电子病案中的实现与应用.结果 通过这种应用,保证了电子病案的安全与可靠,为电子病案的生成、保存、管理和调用提供了安全保障机制.结论 为电子病案与纸质病案具有相同的法律效力,提供了技术上的可能;为有效解决医疗纠纷提供合法的证据支持.

  19. Cognitive Ability and Non-Ability Trait Determinants of Expertise

    Science.gov (United States)

    Ackerman, Phillip L.

    2003-01-01

    Traditional approaches to understanding individual differences determinants of domain-specific expertise have focused on individual trait components, such as ability or topic interest. In contrast, trait complex approaches consider whether combinations of cognitive, affective, and conative traits are particularly facilitative or impeding of the…

  20. Strategies of Adaptive Ability Measurement.

    Science.gov (United States)

    A number of strategies are described for adapting ability test items to individual differences in ability levels of testees. Each strategy consists of a different set of rules for selecting the sequence of test items to be administered to a given testee. Advantages and disadvantages of each strategy are discussed, and research issues unique to the strategy are described. Strategies reviewed are differentiated into two-stage approaches and multi-stage approaches. Several variations of the two-stage approach are described. The various

  1. Learning Anatomy Enhances Spatial Ability

    Science.gov (United States)

    Vorstenbosch, Marc A. T. M.; Klaassen, Tim P. F. M.; Donders, A. R. T.; Kooloos, Jan G. M.; Bolhuis, Sanneke M.; Laan, Roland F. J. M.

    2013-01-01

    Spatial ability is an important factor in learning anatomy. Students with high scores on a mental rotation test (MRT) systematically score higher on anatomy examinations. This study aims to investigate if learning anatomy also oppositely improves the MRT-score. Five hundred first year students of medicine ("n" = 242, intervention) and…

  2. Learning Anatomy Enhances Spatial Ability

    Science.gov (United States)

    Vorstenbosch, Marc A. T. M.; Klaassen, Tim P. F. M.; Donders, A. R. T.; Kooloos, Jan G. M.; Bolhuis, Sanneke M.; Laan, Roland F. J. M.

    2013-01-01

    Spatial ability is an important factor in learning anatomy. Students with high scores on a mental rotation test (MRT) systematically score higher on anatomy examinations. This study aims to investigate if learning anatomy also oppositely improves the MRT-score. Five hundred first year students of medicine ("n" = 242, intervention) and…

  3. Technology and Motor Ability Development

    Science.gov (United States)

    Wang, Lin; Lang, Yong; Luo, Zhongmin

    2014-01-01

    As a new member joining the technology family, active video games have been developed to promote physical exercise. This working-in-progress paper shares an ongoing project on examining the basic motor abilities that are enhanced through participating in commercially available active video games. [For the full proceedings see ED557181.

  4. Ability Estimation for Conventional Tests.

    Science.gov (United States)

    Kim, Jwa K.; Nicewander, W. Alan

    1993-01-01

    Bias, standard error, and reliability of five ability estimators were evaluated using Monte Carlo estimates of the unknown conditional means and variances of the estimators. Results indicate that estimates based on Bayesian modal, expected a posteriori, and weighted likelihood estimators were reasonably unbiased with relatively small standard…

  5. Challenging high-ability students

    NARCIS (Netherlands)

    Scager, Karin; Akkerman, Sanne F.; Pilot, Albert; Wubbels, Theo; Hafd Onderwijsadvies en training; Leerstoel Vermunt; Faculteit Sociale Wetenschappen; LS Wubbels; Education and Learning: Development in Interaction

    2014-01-01

    The existing literature on indicators of an optimal learning environment for high-ability students frequently discusses the concept of challenge. It is, however, not clear what, precisely, constitutes appropriate challenge for these students. In this study, the authors examined an undergraduate hono

  6. Learning anatomy enhances spatial ability.

    NARCIS (Netherlands)

    Vorstenbosch, M.A.T.M.; Klaassen, T.P.; Donders, A.R.T.; Kooloos, J.G.M.; Bolhuis, S.M.; Laan, R.F.J.M.

    2013-01-01

    Spatial ability is an important factor in learning anatomy. Students with high scores on a mental rotation test (MRT) systematically score higher on anatomy examinations. This study aims to investigate if learning anatomy also oppositely improves the MRT-score. Five hundred first year students of me

  7. Challenging High-Ability Students

    Science.gov (United States)

    Scager, Karin; Akkerman, Sanne F.; Pilot, Albert; Wubbels, Theo

    2014-01-01

    The existing literature on indicators of an optimal learning environment for high-ability students frequently discusses the concept of challenge. It is, however, not clear what, precisely, constitutes appropriate challenge for these students. In this study, the authors examined an undergraduate honours course, Advanced Cell Biology, which has…

  8. Challenging high-ability students

    NARCIS (Netherlands)

    Scager, Karin; Akkerman, Sanne F.; Pilot, Albert; Wubbels, Theo; Hafd Onderwijsadvies en training; Leerstoel Vermunt; Faculteit Sociale Wetenschappen; LS Wubbels; Education and Learning: Development in Interaction

    2014-01-01

    The existing literature on indicators of an optimal learning environment for high-ability students frequently discusses the concept of challenge. It is, however, not clear what, precisely, constitutes appropriate challenge for these students. In this study, the authors examined an undergraduate hono

  9. RSA Encryption with the TI-82.

    Science.gov (United States)

    Sigmon, Neil; Yankosky, Bill

    2002-01-01

    Description of integrating one of the most widely used cryptosystems into a mathematics course for Liberal Arts majors. Application of this cryptosystem requires understanding of the concepts of exponentiation and modular arithmetic only. (MM)

  10. Blastomyces dermatitidis infections in the RSA

    African Journals Online (AJOL)

    In the lung, the disease process may be acute or chronic, the .... considered to be a risk factor, it could be expected that blacks would have a much greater .... Hasan FM, Jarrah T, Nassar V. The association of adenocarcinoma of the lung and ...

  11. RSA Asymmetric Cryptosystem beyond Homogeneous Transformation

    African Journals Online (AJOL)

    PROF. O. E. OSUAGWU

    2013-12-01

    Dec 1, 2013 ... It is as old as civilization. Security of information was born out of the consciousness to have private transmission. ... especially useful in the cases of financial and .... c = m e mod n. Where: c is the ciphertext, m is the message, e is ..... Press Series on Discrete Mathematics and its Applications, CRC press,.

  12. INDIVIDUAL ABILITIES AND LIFELONG LEARNING

    Directory of Open Access Journals (Sweden)

    Oleksandr Yu. Burov

    2016-10-01

    Full Text Available This paper describes new and emerging technologies in education, learning environments and methods that have to satisfy lifelong learning, from school age to retirement, on the basis of the psychophysiological model of the cognitive abilities formation. It covers such topics as: evaluation of a human (accounting schoolchildren, youth and adults features abilities and individual propensities, individual trajectory of learning, adaptive learning strategy and design, recommendation on curriculum design, day-to-day support for individual’s learning, assessment of a human learning environment and performance, recommendation regards vocational retraining and/or further carrier etc.. The specific goal is to facilitate a broader understanding of the promise and pitfalls of these technologies and working (learning/teaching environments in global education/development settings, with special regard to the human as subject in the system and to the collaboration of humans and technical, didactic and organizational subsystems.

  13. Noise Exclusion Ability in Infants

    Directory of Open Access Journals (Sweden)

    Geroldene Tsui

    2011-05-01

    Full Text Available An important perceptual ability is to filter out background distractions from relevant information. However, prior research has not identified when this begins in humans. Our study aims to investigate whether noise exclusion ability occurs in infancy. Infants' contrast sensitivity function (CSF was measured by a Baynesian adaptive inference method. Infants' attention was directed to the middle of a monitor where an 8.72 degree static Gabor grating was presented on the left or right side of the monitor. In half the trials, the grating was presented against a gray background; in the other half, against a 16% contrast random-dot noise background. The experimenter and two independent coders judged which side the infants gazed at (force-choice preferential looking paradigm. One-hundred babies aged from 4 to 10 months satisfied the 70% interrater consistency criterion for inclusion. Four parameters defined the best-fitted CSF for each infant. Of these, peak spatial frequency, bandwidth and truncation of CSF were similar in conditions with and without noise. The peak gain estimate was most significantly impaired by external noise, but a marked 31% improvement was observed in 7- to 10-month-olds. This may be the first sign of development of human's noise exclusion ability, and is worth further study.

  14. Implicit learning as an ability.

    Science.gov (United States)

    Kaufman, Scott Barry; Deyoung, Colin G; Gray, Jeremy R; Jiménez, Luis; Brown, Jamie; Mackintosh, Nicholas

    2010-09-01

    The ability to automatically and implicitly detect complex and noisy regularities in the environment is a fundamental aspect of human cognition. Despite considerable interest in implicit processes, few researchers have conceptualized implicit learning as an ability with meaningful individual differences. Instead, various researchers (e.g., Reber, 1993; Stanovich, 2009) have suggested that individual differences in implicit learning are minimal relative to individual differences in explicit learning. In the current study of English 16-17year old students, we investigated the association of individual differences in implicit learning with a variety of cognitive and personality variables. Consistent with prior research and theorizing, implicit learning, as measured by a probabilistic sequence learning task, was more weakly related to psychometric intelligence than was explicit associative learning, and was unrelated to working memory. Structural equation modeling revealed that implicit learning was independently related to two components of psychometric intelligence: verbal analogical reasoning and processing speed. Implicit learning was also independently related to academic performance on two foreign language exams (French, German). Further, implicit learning was significantly associated with aspects of self-reported personality, including intuition, Openness to Experience, and impulsivity. We discuss the implications of implicit learning as an ability for dual-process theories of cognition, intelligence, personality, skill learning, complex cognition, and language acquisition.

  15. The Cultivation of Students’ Speaking Ability

    Institute of Scientific and Technical Information of China (English)

    钱倩

    2014-01-01

    <正>In general,Chinese high school students have been weak in communicating in English.They are too shy to speak in public.So they can’t speak English fluently.That’s a great problem.In class,we should improve students’abilities while learning English,such as listening ability,speaking ability,reading ability,writing ability and translating ability.But I think that students’speaking ability is the most important one in the five abilities.So how can we improve students’speaking ability?

  16. Mathematics, Spatial Ability and the Sexes.

    Science.gov (United States)

    Fennema, Elizabeth

    This report defines spatial ability operationally (consisting of three components) and reviews possible sex differences in this ability as reported in the literature. The relationship between mathematical ability and spatial ability is discussed. Researchable hypotheses about how differential spatial ability may effect mathematics achievement are…

  17. Comparação entre o sistema Petrifilm RSA® e a metodologia convencional para a enumeração de estafilococos coagulase positiva em alimentos Comparison of Petrifilm RSA system with the traditional methodology for the enumeration of coagulase-positive Staphylococcus in foods

    Directory of Open Access Journals (Sweden)

    Anderson de Souza Sant'ana

    2005-09-01

    Full Text Available A pesquisa de estafilococos coagulase positiva em alimentos é feita através de sua detecção e enumeração em meios seletivos e diferenciais e posterior caracterização pelos testes de coagulase, termonuclease, Gram e catalase. Estes testes podem requerer até quatro dias para obtenção dos resultados finais, além do tempo e material dispensados ao seu uso. As placas Petrfilm® RSA são uma alternativa a esta metodologia. No presente estudo, foram analisadas 62 amostras de diferentes alimentos comparando-se a metodologia tradicional (ABP, seguido dos testes de coagulaseou Staphytect Plus e o sistema Petrifilm. O sistema Petrifilm® RSA diferiu significativamente da metodologia tradicional, dando médias de contagem superiores. Ao se considerar colônias típicas e atípicas, o ABP seguido de confirmação pelo Staphytect Plus diferiu significativamente dos demais métodos testados. O Petrifilm RSA é uma alternativa para a enumeração de estafilococos coagulase positivos em alimentos, em virtude do menor tempo (aproximadamente 31 horas, para obter-se resultados realmente quantitativos. Deve-se testar tanto colônias típicas quanto atípicas crescidas no ABP, para se evitar falhas na quantificação dos resultados. Esta contagem é mais significativa ao se usar o teste de aglutinação em látex (Staphytect Plus. A análise de estafilococos em alimentos apresenta diversas limitações.Foods are examined for the presence of coagulase-positive staphylococci using selective and differential media followed by characterization for coagulase, thermoestable nuclease, Gram and catalase tests. These tests may require up to four days to obtain the results, besides time and material used. The Petrifilm® rapid S.aureus count plate is a alternative to traditional methodology. In this study, 62 samples of several foods were analysed comparing the BPA method followed by coagulase or latex agglutination tests and Petrifilm® RSA method. The Petrifilm

  18. Cryptanalysis of RSA with Special Exposed Least Significant Bits of the Private Key%私钥低比特特定泄露下的RSA密码分析

    Institute of Scientific and Technical Information of China (English)

    王世雄; 屈龙江; 李超; 付绍静

    2015-01-01

    基于Coppersmith方法,RSA密码分析取得了许多新结果,其中包括部分私钥泄露攻击与低解密指数攻击.现实中侧信道攻击能够泄露私钥的部分比特位,而部分私钥泄露攻击正是通过泄露的这些比特位来实现对RSA密码的破解.低解密指数攻击则是在解密指数取值较小的条件下来破解RSA,Boneh和Durfee给出了至今最好的结果.针对私钥最低几位比特泄露的攻击,是一类重要的部分私钥泄露攻击,并且和低解密指数攻击紧密相关.基于Coppersmith方法在模多项式方程求小值解的应用,以及线性化模方程的技巧,本文给出了新的针对私钥最低几位比特泄露的攻击结果.其中线性化模方程的技巧,来源于Herrmann和May对于Boneh和Durfee的低解密指数攻击结果的简化证明.注意到目前针对私钥最低几位比特泄露的攻击只关注所泄露比特的位数,而本文还关注所泄露比特的取值.当所泄露比特的取值满足一定的条件时,本文的结果改进了Ernst等人的攻击结果.另外Ernst等人只考虑了加密指数与RSA模基本相等的特殊情况,本文进一步研究了加密指数小于RSA模的一般情况.

  19. Effect of carbohydrate mouth rinsing on multiple sprint performance

    Science.gov (United States)

    2013-01-01

    Background Research suggests that carbohydrate mouth rinsing (CMR) improves endurance performance; yet, little is known regarding the effect of CMR on multiple sprint efforts. As many sports involve multiple sprinting efforts, followed by periods of recovery, the aim of our current study was to investigate the influence of CMR on multiple sprint performance. Methods We recruited eight active males (Age; 22 ± 1 y; 75.0 ± 8.8 kg; estimated VO2max 52.0 ± 3.0 ml/kg/min) to participate in a randomly assigned, double-blind, counterbalanced study administering a CMR (6.4% Maltodextrin) or similarly flavoured placebo solution. Primary outcomes for our study included: (a) time for three repeated sprint ability tests (RSA) and (b) the Loughborough Intermittent Shuttle Test (LIST). Time was expressed in seconds (sec). Secondary outcomes included ratings of perceived exertion (RPE) and blood glucose concentration. Tertiary outcomes included two psychological assessments designed to determine perceived activation (i.e., arousal) and pleasure-displeasure after each section of the LIST. We analysed our data using a two-way analysis of variance (ANOVA) for repeated measures, a Bonferroni adjusted post hoc t-test to determine significant differences in treatment, and a liberal 90% confidence interval between treatment conditions. Effect sizes were calculated between trials and interpreted as ≤ 0.2 trivial, > 0.2 small, > 0.6 moderate, > 1.2 large, > 2 very large and > 4 extremely large. Data are means ± SD. Overall statistical significance was set as P repeated, intermittent, sprint efforts. PMID:24066731

  20. Influence of the mechanical properties of third-generation artificial turf systems on soccer players' physiological and physical performance and their perceptions.

    Directory of Open Access Journals (Sweden)

    Javier Sánchez-Sánchez

    Full Text Available The aim of this research was to evaluate the influence of the mechanical properties of artificial turf systems on soccer players' performance. A battery of perceptive physiological and physical tests were developed on four different structural systems of artificial turf (System 1: Compacted gravel sub-base without elastic layer; System 2: Compacted gravel sub-base with elastic layer; System 3: Asphalt sub-base without elastic layer; System 4: Asphalt sub-base with elastic layer. The sample was composed of 18 soccer players (22.44±1.72 years who typically train and compete on artificial turf. The artificial turf system with less rotational traction (S3 showed higher total time in the Repeated Sprint Ability test in comparison to the systems with intermediate values (49.46±1.75 s vs 47.55±1.82 s (S1 and 47.85±1.59 s (S2; p0.05. The physiological load was similar in all four artificial turf systems. However, players felt more comfortable on the harder and more rigid system (S4; visual analogue scale = 70.83±14.28 than on the softer artificial turf system (S2; visual analogue scale = 54.24±19.63. The lineal regression analysis revealed a significant influence of the mechanical properties of the surface of 16.5%, 15.8% and 7.1% on the mean time of the sprint, the best sprint time and the maximum mean speed in the RSA test respectively. Results suggest a mechanical heterogeneity between the systems of artificial turf which generate differences in the physical performance and in the soccer players' perceptions.

  1. Effects and Sustainability of a 13-Day High-Intensity Shock Microcycle in Soccer

    Directory of Open Access Journals (Sweden)

    Patrick Wahl

    2014-06-01

    Full Text Available The preseason in soccer is a short period of 6-8 weeks where conditional abilities, technical and tactical elements need to be trained. Therefore, time is lacking to perform long term preparation periods for different abilities, especially endurance training. There is evidence that the implementation of high-intensity shock microcycles in preseason training could be one way to improve physical performance in a short period of time. Therefore, the purpose of the present study was to examine the effects and the sustainability of a high-intensity shock microcycle on soccer specific performance. Over 2 weeks, 12 male soccer players (26.1 ± 4.5 years performed 12 high-intensity training (HIT sessions in addition to their usual training. Before (pre, 6 days (6d and 25 days (25d after training, subjects performed Counter Movement Jump (CMJ, Repeated-Sprint Ability (RSA test and Yo-Yo Intermittent Recovery Test Level 2 (YYIR2. Mean sprint time (RSAMean (cohen’s d = -1.15, percentage decrement score (RSAIndex (cohen’s d = -1.99 and YYIR2 (cohen’s d = +1.92 improved significantly from pre to 6d. 25d after, values showed a significant reduction for YYIR2 (cohen’s d = -0.81 and small to moderate but not significant increase for RSAMean (cohen’s d = +0.37 and RSAIndex (cohen’s d = +0.7 compared to 6d values. Small but no significant increases were found for CMJ (cohen’s d = +0.33 and no significant and substantial changes were found for RSABest (cohen’s d = -0.07 from pre to 6d. For competitive soccer players, block periodization of HIT offers a promising way to largely improve RSA and YYIR2 in a short period of time. Despite moderate to large decreases in RSAIndex and YYIR2 performance in the 19 day period without HIT, values still remained significantly higher 25d after the last HIT session compared to pre-values. However, it might be necessary to include isolated high-intensity sessions after a HIT training block in order to maintain the

  2. Alteration of ERβ gene RsaI polymorph ism may contribute to reduced fertilization rate and embryonic developmental competence%ERβ基因RsaI多态性可能降低精子受精力及胚胎的发育潜能

    Institute of Scientific and Technical Information of China (English)

    Qiu-Fang Zhang; Huai-Liang Feng; Lan Zhao; Ping Liu; Li Li; Jie Yan; Jie Qiao

    2011-01-01

    This paper aims to determine the possible role of estrogen receptor-β(ERβ)gene Rsal polymorphism on sperm fertility and early embryonic development in humans. Three groups of Chinese men were recruited: in vitro fertilization (IVF) group, including 374 couples who underwent conventional IVF; intracytoplasmic sperm injection (ICSI) group, including 294 couples who underwent an ICSI procedure using ejaculated sperm; and azoospermic group, consisting of 197 couples who underwent ICSI using either testis or epididymis sperm. Rsal polymorphism in the ERβ gene was detected by polymerase chain reaction (PCR)-restriction fragment length polymorphism technique; fertilization and high-quality embryo rates were evaluated for each group. In each group, no significant differences were found in the overall rates of fertilization and high-quality embryos among GG, AG and AA genotypes. However, the proportion of cycles possessing a satisfactory high-quality embryo rate with the AA genotype was significantly lower than that in the wild-type GG genotype from each group. These results demonstrated that sperm possessing the ERp Rsal A genotype may have reduced fertilization ability and decreased early embryonic developmental potential, which could directly or indirectly contribute to the low fertilization rate and early embryonic developmental arrest in some cases.

  3. Teachers of high ability pupils

    Directory of Open Access Journals (Sweden)

    Cándido Genovard

    2010-04-01

    Full Text Available In this article we analyze the characteristics of gifted and talented students’ expert teachers. The subject background and the specific proprieties of the instructional process to meet gifted students’ educational needs are analyzed. The value of teacher-student interactions and of teaching and learning styles are highlighted. Also, we include different action guidelines and instructional resources to use in the classroom to teach these students. There is not an ideal teacher for high ability students. However, teachers must know what the teaching-learning processes are and how these work, and the diverse psychological, content and contextual variables involved in such processes.

  4. The Data Set on the Multiple Abilities

    DEFF Research Database (Denmark)

    Klynge, Alice Heegaard

    2008-01-01

    This paper presents a data set on multiple abilities. The abilities cover the Literacy and Math Ability, the Creative and Innovative Ability, the Learning Ability, the Communication Ability, the Social Competency, the Self-Management Ability, the Environmental Awareness, the Civic Competency......, the Intercultural Awareness, and the Health Awareness. The data stems from a unique cross-sectional survey carried out for the adult population in Denmark. Several dimensions and many questions pinpoint and measure every ability. The dimensions cover areas such as the individual behavior at work, the individual...

  5. The Data Set on the Multiple Abilities

    DEFF Research Database (Denmark)

    Klynge, Alice Heegaard

    2008-01-01

    , the Intercultural Awareness, and the Health Awareness. The data stems from a unique cross-sectional survey carried out for the adult population in Denmark. Several dimensions and many questions pinpoint and measure every ability. The dimensions cover areas such as the individual behavior at work, the individual......This paper presents a data set on multiple abilities. The abilities cover the Literacy and Math Ability, the Creative and Innovative Ability, the Learning Ability, the Communication Ability, the Social Competency, the Self-Management Ability, the Environmental Awareness, the Civic Competency...

  6. Assessing Algebraic Solving Ability: A Theoretical Framework

    Science.gov (United States)

    Lian, Lim Hooi; Yew, Wun Thiam

    2012-01-01

    Algebraic solving ability had been discussed by many educators and researchers. There exists no definite definition for algebraic solving ability as it can be viewed from different perspectives. In this paper, the nature of algebraic solving ability in terms of algebraic processes that demonstrate the ability in solving algebraic problem is…

  7. Cognitive processing of drawing abilities.

    Science.gov (United States)

    Guérin, F; Ska, B; Belleville, S

    1999-08-01

    This critical review examines constructional apraxia from a cognitive neuropsychological perspective. To our knowledge, van Sommers (1989) is the only researcher to present a global cognitive model of drawing abilities. He organizes it into two hierarchical systems: Marr's model of visual perception and a graphic production system. The latter comprises four hierarchically organized components: depiction decisions, production strategy, contingent planning, and articulatory and economic constraints. Van Sommers' model will be discussed in light of other models and on the basis of empirical neuropsychological studies (Farah, 1984; Kosslyn & Koenig, 1992; Roncato, Sartori, Masterson, & Rumiati, 1987; van Sommers, 1989). We find that: (1) the Kosslyn and Koenig visual perception model describes more accurately the perceptual components underlying copying than the visual perception system of van Sommers' drawing model, (2) Van Sommers' arguments in favor of a depiction processing as opposed to visual imagery are not convincing, (3) Van Sommers' assumption that a production strategy is a component is unclear, and (4) articulatory and economic constraints are not cognitive components, but constraints imposed during action programming. This literature review leads to a discussion of future research topics and the specificity of constructional apraxia. Copyright 1999 Academic Press.

  8. How to Develop Students' Writing Ability

    Institute of Scientific and Technical Information of China (English)

    ChenHuigen

    2000-01-01

    Keynote: This dissertation presents an analysis of the cause of students' low ability of writing, emphasizes the interrelations of the 4 abilities and focuses on the importance of the change of English teachers' concepts.

  9. Improvement of Speaking Ability through Interrelated Skills

    Science.gov (United States)

    Liao, Guoqiang

    2009-01-01

    How to improve students' ability of speaking English? That is the key point we are concerned about. This paper discusses the possibility and necessity of improving students' ability by combining the four skills of speaking, listening, reading and writing.

  10. Specific physical trainability in elite young soccer players: efficiency over 6 weeks’ in-season training

    Directory of Open Access Journals (Sweden)

    M Chtara

    2017-04-01

    Full Text Available The aim of the present study was to compare the effects of 3 training protocols (plyometric [PLYO], agility [AG], or repeated shuttle sprints [RS] on physical performance in the same population of young soccer players. Forty-two youth-level male players (13.6±0.3-years; 1.65±0.07 m; 54.1±6.5 kg; body fat: 12.8±2.6% participated in a short-term (6-week randomized parallel fully controlled training study (pre-to-post measurements: PLYO group, n=10; AG group, n=10; RS group, n=12; and control group [CON] n=10. PLYO training = 9 lower limb exercises (2-3 sets of 8-12 repetitions. The AG group performed planned AG drills and direction changes. RS training consisted of 2-4 sets of 5-6x 20 to 30 m shuttle sprints (20 seconds recovery in between. Progressive overload principles were incorporated into the programme by increasing the number of foot contacts and varying the complexity of the exercises. Pre/post-training tests were: bilateral standing horizontal jump, and unilateral horizontal jumps, sprint (30 m with 10 m lap time, agility (20 m zigzag, and repeated sprint ability (RSA (i.e. 6x30 m shuttle sprints: 2x15 m with 180° turns. Significant main effects for time (i.e. training application and group (training type were detected. Improvements in horizontal jumping were higher (p<0.01: ES=large in PLYO. The RS group improved significantly more (p<0.01; ES=large than other groups: 30 m sprint, RSAbest and RSAmean performances. Significantly greater increases in 20 m zigzag performance were observed following AG and RS training (4.0 and 3.8%, respectively compared with PLYO (2.0% and CON training (0.8%. No significant differences were reported in the RSAdec between groups. Elite young male soccer players’ physical performances can be significantly and specifically improved either using PLYO or AG or RSA training over short-term in-season training.

  11. Innovative Allies: Spatial and Creative Abilities

    Science.gov (United States)

    Coxon, Steve V.

    2012-01-01

    Spatial and creative abilities are important for innovations in science, technology, engineering, and math (STEM) fields, but talents are rarely developed from these abilities by schools, including among gifted children and adolescents who have a high potential to become STEM innovators. This article provides an overview of each ability and makes…

  12. Explaining High Abilities of Nobel Laureates

    Science.gov (United States)

    Shavinina, Larisa

    2004-01-01

    Although the Nobel Prize is associated with a rare, superior degree of intellectually creative achievement, high abilities of Nobel laureates are far from well explained. This paper argues that Nobel laureates' high abilities are determined in part by their extracognitive abilities, that is, specific feelings, preferences, beliefs and intuitive…

  13. Discrimination ability of the Energy score

    DEFF Research Database (Denmark)

    Pinson, Pierre; Tastu, Julija

    as appealing since being proper, we show that its discrimination ability may be limited when focusing on the dependence structure of multivariate probabilistic forecasts. For the case of multivariate Gaussian process, a theoretical upper for such discrimination ability is derived and discussed. This limited...... discrimination ability may eventually get compromised by computational and sampling issues, as dimension increases....

  14. Comparison of the Anthropometric and Physical Characteristics of International and Provincial Rugby Sevens Players.

    Science.gov (United States)

    Ross, Alex; Gill, Nicholas D; Cronin, John B

    2015-09-01

    Anthropometrical and physical characteristics have been used to distinguish players of different competition levels and position groups; however, there is no literature on rugby sevens. To compare the anthropometrical and physical characteristics of international and provincial rugby sevens players and between forwards and backs. To assess whether differences exist, 65 rugby sevens players including 22 international players and 43 provincial-level players were assessed for height, mass, body composition, speed, repeated-sprint ability, lower-body power, upper-body strength, and maximal aerobic endurance during in-season preparation for tournaments. Clear differences (2.8-32%; small to very large effect sizes) were observed in all anthropometrical and physical measures between international and provincial players, with the largest differences observed in repeated-sprint ability (5.7%; very large effect size), 40-m-sprint time (4.4%; large effect size), 50-kg squat-jump peak power (32%; large effect size), and multistage fitness-test performance (19%; large effect size). Fewer and smaller differences (0.7-14%; trivial to large effect sizes) were found when comparing forwards and backs, with body height being the most discriminant characteristic (3.5%; large effect size). Lower-level rugby sevens players should seek to improve their overall physical profile, particularly their repeated-sprint ability, to reach higher levels in rugby sevens. Furthermore, positional status may have little importance when preparing for rugby sevens.

  15. Caffeine Ingestion Improves Repeated Freestyle Sprints in Elite Male Swimmers

    Directory of Open Access Journals (Sweden)

    Paul S.R. Goods, Grant Landers, Sacha Fulton

    2017-03-01

    Full Text Available The purpose of this investigation was to determine the efficacy of a moderate dose of caffeine to improve repeat-sprint performance in elite freestyle sprinters. Nine highly trained male swimmers performed 6 x 75 m freestyle sprints on two occasions 1-h after consuming either 3 mg·kg-1 caffeine (CAF, or placebo, in a cross-over manner. Capillary blood samples for the analysis of blood lactate concentration and pH were collected after the 1st, 3rd, and 5th sprint, while heart rate and perceived exertion (RPE were collected after every sprint. There was a moderate effect for improved mean sprint time in the CAF condition (0.52 s; 1.3%; d = 0.50. When assessed individually, there was a large effect for improved performance in sprints 3 (1.00 s; 2.5%; d = 1.02 and 4 (0.84 s; 2.1%; d = 0.84 in CAF compared to placebo, with worthwhile performance improvement found for each of the first 5 sprints. There was a significant treatment effect for higher blood lactate concentration for CAF (p = 0.029, and a significant treatment*time effect for reduced pH in the CAF condition (p = 0.004. Mean heart rate (167 ± 9 bpm vs 169 ± 7 bpm and RPE (17 ± 1 vs 17 ± 1 were not different between placebo and CAF trials, respectively. This investigation is the first to demonstrate enhanced repeat-sprint ability in swimmers following acute caffeine ingestion. It appears likely that the combination of a moderate dose of caffeine (3-6 mg·kg-1 with trained athletes is most likely to enhance repeat-sprint ability in various athletic populations; however, the exact mechanism(s for an improved repeat-sprint ability following acute caffeine ingestion remain unknown.

  16. Children's Cognitive Abilities and Intrahousehold Parental Investment

    OpenAIRE

    Andrew Zuppann

    2013-01-01

    I estimate how new information about children's cognitive abilities leads parents to adjust investment within and across children. I use the National Longitudinal Survey of Youth matched mother-child data to construct measures of both child cognitive ability and parental investment during childhood. I find that parents respond to improvements in a child's cognitive abilities by devoting more resources towards that child. Â I find that positive information about one child leads to compensating...

  17. Self-Care Ability in Hemodialysis Patients

    OpenAIRE

    Atashpeikar, Soulmaz; Jalilazar, Tahereh; Heidarzadeh, Mehdi

    2012-01-01

    Introduction: Considering the numerous physical and psychological problems in hemo-dialysis patients, they are dependent on others in some daily activities and in fact, they do not have full self-care ability. A few studies have ever been done, particularly in Iran, on self-care ability of hemodialysis patients. The present study aimed to determine self-care ability of these patients in addition to evaluate its association with some demo-graphic characteristics. Methods: Thi...

  18. The relationship between comprehension and metacomprehension ability.

    Science.gov (United States)

    Maki, R H; Jonas, D; Kallod, M

    1994-03-01

    We investigated the relationship between the ability to comprehend text and the ability to predict future performance and to assess past performance on text. Subjects were poor at predicting performance, which may be why prediction accuracy did not relate to measures of comprehension ability. Measures of comprehension ability did relate to the accuracy with which subjects assessed their performance on tests. Better and faster comprehenders judged their relative levels of test performance over sections of text more accurately than did poorer and slower comprehenders.

  19. Study on Loading Ability of Straw Bale

    Institute of Scientific and Technical Information of China (English)

    LIU Kun; JIANG Enchen; DUAN Jieli

    2006-01-01

    The loading ability of straw bale was tested by Electronical Testing Machine. The linear regression equations were proposed between failure density and loading ability, and failure density and compressing energy.Based on an exponent model, the testing coefficients of straw bale were estimated using Levenberg-Marquardt Method. The results of test showed that the relation between failure density and loading ability and compressing energy was linear in the phase of high density. The loading ability of straw bale could meet the building bill.

  20. Risk Aversion Relates to Cognitive Ability

    DEFF Research Database (Denmark)

    Andersson, Ola; Holm, Håkan J.; Tyran, Jean-Robert Karl

    2016-01-01

    Recent experimental studies suggest that risk aversion is negatively related to cognitive ability. In this paper we report evidence that this relation might be spurious. We recruit a large subject pool drawn from the general Danish population for our experiment. By presenting subjects with choice...... tasks that vary the bias induced by random choices, we are able to generate both negative and positive correlations between risk aversion and cognitive ability. Structural estimation allowing for heterogeneity of noise yields no significant relation between risk aversion and cognitive ability. Our...... results suggest that cognitive ability is related to random decision making, rather than to risk preferences....

  1. Risk aversion relates to cognitive ability

    DEFF Research Database (Denmark)

    Andersson, Ola; Holm, Håkan J.; Tyran, Jean-Robert Karl

    Recent experimental studies suggest that risk aversion is negatively related to cognitive ability. In this paper we report evidence that this relation might be spurious. We recruit a large subject pool drawn from the general Danish population for our experiment. By presenting subjects with choice...... tasks that vary the bias induced by random choices, we are able to generate both negative and positive correlations between risk aversion and cognitive ability. Structural estimation allowing for heterogeneity of noise yields no significant relation between risk aversion and cognitive ability. Our...... results suggest that cognitive ability is related to random decision making rather than to risk preferences....

  2. Effects of sports massage and intermittent cold-water immersion on recovery from matches by basketball players.

    Science.gov (United States)

    Delextrat, Anne; Calleja-González, Julio; Hippocrate, Audrey; Clarke, Neil David

    2013-01-01

    The aim of this study was to compare the effects of intermittent cold-water immersion and massage on perceptual and performance markers of recovery by basketball players after competitive matches. Eight men (age 23 ± 3 years; stature 190.5 ± 8.9 cm; body mass 90.3 ± 9.6 kg; body fat 12.8 ± 4.8%) and eight women (age 22 ± 2 years; stature 179.0 ± 8.5 cm; body mass 77.6 ± 9.2 kg; body fat 22.5 ± 6.6%) basketball players participated. Massage, cold-water immersion or control were applied immediately after competitive matches, followed by assessments of perceptual measures of recovery and physical performance, countermovement jump and repeated-sprint ability 24 h after intervention. There was lower perception of fatigue overall and in the legs immediately after the massage and cold-water immersion condition (P recovery interventions on repeated-sprint measures (P at best 0.067, η²(P) at best 0.68). The results suggest that both massage and cold-water immersion improve perceptual measures of recovery. Furthermore, cold-water immersion improves jump performance although neither such immersion nor massage had an effect on repeated-sprint ability. This suggests that, overall, cold-water immersion is more useful than massage in the recovery from basketball matches, especially in women.

  3. Face recognition: a model specific ability

    Directory of Open Access Journals (Sweden)

    Jeremy B Wilmer

    2014-10-01

    Full Text Available In our everyday lives, we view it as a matter of course that different people are good at different things. It can be surprising, in this context, to learn that most of what is known about cognitive ability variation across individuals concerns the broadest of all cognitive abilities, often labeled g. In contrast, our knowledge of specific abilities, those that correlate little with g, is severely constrained. Here, we draw upon our experience investigating an exceptionally specific ability, face recognition, to make the case that many specific abilities could easily have been missed. In making this case, we derive key insights from earlier false starts in the measurement of face recognition’s variation across individuals, and we highlight the convergence of factors that enabled the recent discovery that this variation is specific. We propose that the case of face recognition ability illustrates a set of tools and perspectives that could accelerate fruitful work on specific cognitive abilities. By revealing relatively independent dimensions of human ability, such work would enhance our capacity to understand the uniqueness of individual minds.

  4. On factors influencing students’ listening abilities

    Institute of Scientific and Technical Information of China (English)

    胡天秀

    2012-01-01

    As we all know,listening,speaking,reading,and writing are four basic skills in language teaching and learning.Listening plays an important role in improving other skills.There are some factors influencing students’ listening abilities.So it’s important for teachers to improve students’ listening abilities.

  5. Spatial Ability Learning through Educational Robotics

    Science.gov (United States)

    Julià, Carme; Antolí, Juan Òscar

    2016-01-01

    Several authors insist on the importance of students' acquisition of spatial abilities and visualization in order to have academic success in areas such as science, technology or engineering. This paper proposes to discuss and analyse the use of educational robotics to develop spatial abilities in 12 year old students. First of all, a course to…

  6. Credit Ratings and Bank Monitoring Ability

    NARCIS (Netherlands)

    Nakamura, L.I.; Roszbach, K.

    2010-01-01

    In this paper we use credit rating data from two Swedish banks to elicit evidence on these banks’ loan monitoring ability. We do so by comparing the ability of bank ratings to predict loan defaults relative to that of public ratings from the Swedish credit bureau. We test the banks’ abilility to for

  7. Contour Line Portraits: Excited about Artistic Abilities

    Science.gov (United States)

    Neal, Kari Gertz

    2012-01-01

    In this article, the author describes a self-portrait project that encouraged students, boosted their self-confidence, and got them excited about their artistic abilities--while producing amazing results. This lesson effectively develops artistic ability by compelling students to see that drawing is quite simply breaking down objects into the…

  8. DEVELOPING STUDENTS' READING ABILITIES IN JUNIOR SCHOOL

    Institute of Scientific and Technical Information of China (English)

    Duan Bixi

    2001-01-01

    In This Article, the writer focus on an over- all analysis of the present situation of the students' reading activities in junior middle school in the countryside and put forward some suggestions on improving the teaching arts to enhance the students' fast reading abilities . It provided some theoretical basis on the further improcement of students' reading abilities in the school

  9. Does Classmate Ability Influence Students' Social Skills?

    Science.gov (United States)

    Gottfried, Michael A.

    2015-01-01

    Empirically, the link between classmate ability and individual-level student achievement has been established. And yet, within the scope of this body of literature, there is a dearth of studies examining if a relationship also persists between classmate ability and non-achievement outcomes--that is, social skills. This article fills this research…

  10. Adolescents' Conceptions of Ability and Intelligence.

    Science.gov (United States)

    Nicholls, John G.

    Adolescents' developing sense of competence is based on two domains, ability and intelligence. Intelligence testing generally presumes a conception of ability as current capacity that limits the extent to which effort can improve performance. Conceptions of intelligence, and other skills, involve implications about the nature of different forms of…

  11. High Ability Students' Voice on Learning Motivation

    Science.gov (United States)

    Garn, Alex C.; Jolly, Jennifer L.

    2014-01-01

    This study used a self-determination theory lens to investigate high ability learners' motivational experiences. Participants were 15 high ability youth involved in a summer learning camp for gifted students. Two major themes emerged from qualitative data analysis: (a) "The Fun Factor of Learning" and (b) "The Rewards and Pressures…

  12. Purpose in Life among High Ability Adolescents

    Science.gov (United States)

    Bronk, Kendall Cotton; Finch, W. Holmes; Talib, Tasneem L.

    2010-01-01

    Leading high ability scholars have proposed theories that suggest a purpose in life may be particularly prevalent among high ability youth; however, the prevalence of purpose has not been empirically assessed among this population. Therefore using in-depth interviews the present study established the prevalence of purpose among a sample of high…

  13. Assessing Social Ability in Online Learning Environments

    Science.gov (United States)

    Laffey, James; Lin, Guan Yu; Lin, Yimei

    2006-01-01

    Education is a social practice and the ability to interact socially is important to social cognitive learning and social learning. Online education is frequently criticized because it lacks social interaction, a sense of social engagement, and the benefits of learning with others. Social ability with computer-mediated social mechanisms is key to…

  14. Farmers’Political Cognition and Political Ability

    Institute of Scientific and Technical Information of China (English)

    曾子成

    2015-01-01

    [Abstract]In order to provide a new theoretical perspective for the academic research, the group measured political cognition on account of Almond scale. We had found that farmers' political cognition is related to their subjective political ability but not to objective ability, at last we supposed elaborate vil age cadres'function in giving political information publicity.

  15. Improvisation as Ability, Culture, and Experience

    Science.gov (United States)

    Higgins, Lee; Mantie, Roger

    2013-01-01

    We argue in this article for greater role for improvisation in the music classroom. Based on an extensive examination of scholarship about improvisational practices, we propose three conceptualizations--ability, culture, experience--that can serve to guide the teaching of improvisation. When considered as an "ability," improvisation is a…

  16. Dissociating the ability and propensity for empathy

    NARCIS (Netherlands)

    Keysers, Christian; Gazzola, Valeria

    2014-01-01

    Neuroimaging suggests psychopaths have reduced vicarious activations when simply witnessing pain but less so when asked to empathize. This inspired us to distinguish the ability from the propensity to empathize. We argue that (i) this ability-propensity distinction is crucial to characterizing empat

  17. Dissociating the ability and propensity for empathy

    NARCIS (Netherlands)

    Keysers, Christian; Gazzola, Valeria

    2014-01-01

    Neuroimaging suggests psychopaths have reduced vicarious activations when simply witnessing pain but less so when asked to empathize. This inspired us to distinguish the ability from the propensity to empathize. We argue that (i) this ability-propensity distinction is crucial to characterizing empat

  18. Control coordination abilities in shock combat sports

    Directory of Open Access Journals (Sweden)

    Natalya Boychenko

    2014-12-01

    Full Text Available Purpose: optimize the process control level of coordination abilities in martial arts. Material and Methods: analysis and compilation of scientific and methodological literature, interviews with coaches of drum martial arts, video analysis techniques, teacher observations. Results: identified specific types of coordination abilities in shock combat sports. Pod branny and offered specific and nonspecific tests to monitor the level of species athletes coordination abilities. Conclusion: it is determined that in order to achieve victory in the fight martial artists to navigate the space to be able to assess and manage dynamic and spatio-temporal parameters of movements, maintain balance, have a high coordination of movements. The proposed tests to monitor species coordination abilities athletes allow an objective assessment of not only the overall level of coordination, and the level of specific types of manifestations of this ability.

  19. Verbal ability, argument order, and attitude formation

    Directory of Open Access Journals (Sweden)

    Mindaugas Mozuraitis

    2016-09-01

    Full Text Available The current study explored the interaction of verbal ability and presentation order on readers’ attitude formation when presented with two-sided arguments. Participants read arguments for and against compulsory voting and genetic engineering, and attitudes were assessed before and after reading the passages. Participants’ verbal ability was measured combining vocabulary knowledge and reading comprehension skill. Results suggested that low verbal-ability participants were more persuaded by the most recent set of arguments whereas high verbal-ability participants formed attitudes independent of presentation order. Contrary to previous literature, individual differences in the personality trait, need for cognition, did not interact with presentation order. The results suggest that verbal ability is an important moderator of the effect of presentation order when formulating opinions from complex prose.

  20. Environmental change enhances cognitive abilities in fish.

    Directory of Open Access Journals (Sweden)

    Alexander Kotrschal

    Full Text Available Flexible or innovative behavior is advantageous, especially when animals are exposed to frequent and unpredictable environmental perturbations. Improved cognitive abilities can help animals to respond quickly and adequately to environmental dynamics, and therefore changing environments may select for higher cognitive abilities. Increased cognitive abilities can be attained, for instance, if environmental change during ontogeny triggers plastic adaptive responses improving the learning capacity of exposed individuals. We tested the learning abilities of fishes in response to experimental variation of environmental quality during ontogeny. Individuals of the cichlid fish Simochromis pleurospilus that experienced a change in food ration early in life outperformed fish kept on constant rations in a learning task later in life--irrespective of the direction of the implemented change and the mean rations received. This difference in learning abilities between individuals remained constant between juvenile and adult stages of the same fish tested 1 y apart. Neither environmental enrichment nor training through repeated neural stimulation can explain our findings, as the sensory environment was kept constant and resource availability was changed only once. Instead, our results indicate a pathway by which a single change in resource availability early in life permanently enhances the learning abilities of animals. Early perturbations of environmental quality may signal the developing individual that it lives in a changing world, requiring increased cognitive abilities to construct adequate behavioral responses.

  1. Host country language ability and expatriate adjustment

    DEFF Research Database (Denmark)

    Selmer, Jan; Lauring, Jakob

    2015-01-01

    Research has shown that expatriates’ host country language ability is positively associated with their adjustment. But does the advantage of expatriates’ language ability depend on the difficulty of the host language? To examine this issue, data were collected from expatriates in two European...... countries, one with an easy, relatively simple language and the other with a difficult, highly complex language. Consistent with Goal-Setting Theory, results indicated a relative advantage of expatriates’ language ability in terms of their adjustment in the host country with the difficult language...... as opposed to the host country with an easy language....

  2. Hierarchical Structure of Abilities: Factorial Validation of Higher Order Constructs in Thurstone's Primary Mental Abilities.

    Science.gov (United States)

    Paden, Patricia

    1981-01-01

    Thurstone's primary mental abilities (1938/1968) involving 57 tests were factor analyzed to produce a comprehensive hierarchical model. Kaiser's varimax solution for primary mental abilities served as the raw data for this study. (Author/GK)

  3. Reliability and criterion-related validity of a new repeated agility test

    Directory of Open Access Journals (Sweden)

    MS Fessi

    2016-04-01

    Full Text Available The study aimed to assess the reliability and the criterion-related validity of a new repeated sprint T-test (RSTT that includes intense multidirectional intermittent efforts. The RSTT consisted of 7 maximal repeated executions of the agility T-test with 25 s of passive recovery rest in between. Forty-five team sports players performed two RSTTs separated by 3 days to assess the reliability of best time (BT and total time (TT of the RSTT. The intra-class correlation coefficient analysis revealed a high relative reliability between test and retest for BT and TT (>0.90. The standard error of measurement (<0.50 showed that the RSTT has a good absolute reliability. The minimal detectable change values for BT and TT related to the RSTT were 0.09 s and 0.58 s, respectively. To check the criterion-related validity of the RSTT, players performed a repeated linear sprint (RLS and a repeated sprint with changes of direction (RSCD. Significant correlations between the BT and TT of the RLS, RSCD and RSTT were observed (p<0.001. The RSTT is, therefore, a reliable and valid measure of the intermittent repeated sprint agility performance. As this ability is required in all team sports, it is suggested that team sports coaches, fitness coaches and sports scientists consider this test in their training follow-up.

  4. Spatial Ability And Learning To Program

    Directory of Open Access Journals (Sweden)

    Sue Jones

    2008-01-01

    Full Text Available Results in introductory computer programming modules are often disappointing, and various individual differences have been found to be relevant. This paper reviews work in this area, with particular reference to the effect of a student's spatial ability. Data is presented on a cohort of 49 students enrolled on an MSc in Information Technology course at a university in the UK. A measure was taken of their mental rotation ability, and a questionnaire administered that focused on their previous academic experience, and expectations relating to the introductory computer programming module they were studying. The results showed a positive correlation between mental rotation ability and success in the module (r = 0.48. Other factors, such as confidence level, expected success, and programming experience, were also found to be important. These results are discussed in relation to the accessibility of programming to learners with low spatial ability.

  5. Cultural Capital and Teaching Ability Rating

    DEFF Research Database (Denmark)

    Jæger, Mads Meier

    This paper studies the effect of cultural capital on teachers’ ratings of children’s oral and math ability. Cultural reproduction theory hypothesises that, holding everything else constant, children who possess cultural capital are more likely to be perceived by teachers as gifted than children who...... do not possess cultural capital. This paper uses extremely rich longitudinal data that provides a better basis than previous studies for holding ‘everything else’ constant. In addition to children and parents’ cultural capital, I control for children’s actual academic ability, physical appearance......, health impairments, social behaviour, antenatal influences, and many family background characteristics. My analysis shows, first, that both children and parents’ cultural capital have independent effects on teacher ability ratings. Second, for oral ability I find that parents’ cultural capital ‘protects...

  6. Cultural Capital and Teaching Ability Rating

    DEFF Research Database (Denmark)

    Jæger, Mads Meier

    , health impairments, social behaviour, antenatal influences, and many family background characteristics. My analysis shows, first, that both children and parents’ cultural capital have independent effects on teacher ability ratings. Second, for oral ability I find that parents’ cultural capital ‘protects......This paper studies the effect of cultural capital on teachers’ ratings of children’s oral and math ability. Cultural reproduction theory hypothesises that, holding everything else constant, children who possess cultural capital are more likely to be perceived by teachers as gifted than children who...... do not possess cultural capital. This paper uses extremely rich longitudinal data that provides a better basis than previous studies for holding ‘everything else’ constant. In addition to children and parents’ cultural capital, I control for children’s actual academic ability, physical appearance...

  7. TIE: an ability test of emotional intelligence

    National Research Council Canada - National Science Library

    Śmieja, Magdalena; Orzechowski, Jarosław; Stolarski, Maciej S

    2014-01-01

    The Test of Emotional Intelligence (TIE) is a new ability scale based on a theoretical model that defines emotional intelligence as a set of skills responsible for the processing of emotion-relevant information...

  8. Idiot Savants: A Categorization of Abilities

    Science.gov (United States)

    Hill, A. Lewis

    1974-01-01

    Reported from a search of 52 sources are categories of special abilities such as fine sensory discriminations and calendar calculations demonstrated by idiot savants (retarded persons exhibiting an unusually developed skill in some special task). (CL)

  9. Cognitive Ability, Principled Reasoning and Political Tolerance

    DEFF Research Database (Denmark)

    Hebbelstrup Rye Rasmussen, Stig; Nørgaard, Asbjørn Sonne

    Individuals are not equally politically tolerant. To explain why, individual differences in emotions and threat have received much scholarly attention in recent years. However, extant research also shows that psychological dispositions, habitual cognitive styles, ideological orientation...... and ‘principled reasoning’ influence political tolerance judgments. The extent to which cognitive ability plays a role has not been entertained even if the capacity to think abstractly, comprehend complex ideas and apply abstract ideas to concrete situations is inherent to both principled tolerance judgment...... and cognitive ability. Cognitive ability, we argue and show, adds to the etiology of political tolerance. In Danish and American samples cognitive ability strongly predicts political tolerance after taking habitual cognitive styles (as measured by personality traits), education, social ideology, and feelings...

  10. Generalist genes and high cognitive abilities.

    Science.gov (United States)

    Haworth, Claire M A; Dale, Philip S; Plomin, Robert

    2009-07-01

    The concept of generalist genes operating across diverse domains of cognitive abilities is now widely accepted. Much less is known about the etiology of the high extreme of performance. Is there more specialization at the high extreme? Using a representative sample of 4,000 12-year-old twin pairs from the UK Twins Early Development Study, we investigated the genetic and environmental overlap between web-based tests of general cognitive ability, reading, mathematics and language performance for the top 15% of the distribution using DF extremes analysis. Generalist genes are just as evident at the high extremes of performance as they are for the entire distribution of abilities and for cognitive disabilities. However, a smaller proportion of the phenotypic intercorrelations appears to be explained by genetic influences for high abilities.

  11. Videogame interventions and spatial ability interactions

    Directory of Open Access Journals (Sweden)

    Thomas S. Redick

    2014-03-01

    Full Text Available Numerous research studies have been conducted on the use of videogames as tools to improve one’s cognitive abilities. While meta-analyses and qualitative reviews have provided evidence that some aspects of cognition such as spatial imagery are modified after exposure to videogames, other evidence has shown that matrix reasoning measures of fluid intelligence do not show evidence of transfer from videogame training. In the current work, we investigate the available evidence for transfer specifically to nonverbal intelligence and spatial ability measures, given recent research that these abilities may be most sensitive to training on cognitive and working memory tasks. Accordingly, we highlight a few studies that on the surface provide evidence for transfer to spatial abilities, but a closer look at the pattern of data does not reveal a clean interpretation of the results. We discuss the implications of these results in relation to research design and statistical analysis practices.

  12. Assessing functional ability in older patients

    DEFF Research Database (Denmark)

    Nielsen, Louise Møldrup; Maribo, Thomas; Nielsen, Hanne Grethe

    2014-01-01

    Aim: This study aimed to develop an understanding of how primary and secondary care health professionals perceive current practice and challenges in assessing older patients’ functional abilities. A secondary aim was to gain insight into how these professionals perceive the need for generic tools...... for assessing functional ability among older patients. Method: A qualitative design was used to explore health professionals’ perspectives on the assessment of older patients’ functional ability. Two groups of health professionals participated in focus group interviews, with one group for each of the two...... from the hospital expressed a need for a fast and simple screening tool to identify those in need of further rehabilitation and care after discharge. Participants from the municipality expressed a need for a more detailed assessment tool to capture information about patients’ ability to perform daily...

  13. Training Teachers for Mixed Ability Classes

    Science.gov (United States)

    Wragg, E. C.

    1978-01-01

    Discusses the preparation of student teachers for mixed ability classes, based on the Nottingham/Leicester project. Outlines a ten-point attack highlighting the areas in which young teachers need to acquire professional skills. (Author/RK)

  14. Cognitive abilities, sociocultural background and academic achievement

    OpenAIRE

    Diniz, António; Pocinho, Margarida Maria Ferreira Diogo Dias; Almeida,Leandro Silva

    2011-01-01

    The infl uence of students’ sociocultural background on academic achievement is a well established fact. Research also points out that sociocultural background is related to students’ cognitive abilities and these have an effect on their academic achievement. However, the mediator role of cognitive abilities on the relationship between sociocultural background and academic achievement is less well known. A structural equation model that represents these relationships was tested in a sample...

  15. The Skills of Improving Reading Ability

    Institute of Scientific and Technical Information of China (English)

    汤瑷宁; 程丽州

    2015-01-01

    Speaking and listening are important to them who wants to improve their ability in English.It is the same to reading.The paper focuses on the skills of improving reading ability.An efficient reader determines beforehand why he is reading a particular selection and he decides which strategies and skills he will use to achieve his goal.There are two basic skills: language skills and reading skills.

  16. The Skills of Improving Reading Ability

    Institute of Scientific and Technical Information of China (English)

    汤瑷宁; 程丽州

    2015-01-01

    Speaking and listening are important to them who wants to improve their ability in English.It is the same to reading. The paper focuses on the skills of improving reading ability. An efficient reader determines beforehand why he is reading a particular selection and he decides which strategies and skills he will use to achieve his goal.There are two basic skills: language skills and reading skills.

  17. Compilation of Pilot Cognitive Ability Norms

    Science.gov (United States)

    2011-12-01

    has amassed a body of knowledge about many topics .87 Comprehension (Comp) Measures “ social acculturation ,” “ social intelligence,” and the...AFRL-SA-WP-TR-2012-0001 COMPILATION OF PILOT COGNITIVE ABILITY NORMS Raymond E. King U.S Air Force School of Aerospace Medicine...2011 4. TITLE AND SUBTITLE Compilation of Pilot Cognitive Ability Norms 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER

  18. On the Origins of Calculation Abilities

    OpenAIRE

    Ardila, A.

    1993-01-01

    A historical review of calculation abilities is presented. Counting, starting with finger sequencing, has been observed in different ancient and contemporary cultures, whereas number representation and arithmetic abilities are found only during the last 5000–6000 years. The rationale for selecting a base of ten in most numerical systems and the clinical association between acalculia and finger agnosia are analyzed. Finger agnosia (as a restricted form of autotopagnosia), right–left discrimina...

  19. Metaphoric competence and communicative language ability

    OpenAIRE

    Littlemore, Jeannette; Low, Graham

    2006-01-01

    Recent developments in cognitive linguistics have highlighted the importance as well as the ubiquity of metaphor in language. Despite this, the ability of second language learners to use metaphors is often still not seen as a core ability. In this paper, we take a model of communicative competence that has been widely influential in both language teaching and language testing, namely Bachman (1990), and argue, giving a range of examples of language use and learner difficulty, that metaphoric ...

  20. How to Improve English iistening Ability

    Institute of Scientific and Technical Information of China (English)

    马丽芳

    2012-01-01

    Language is a means of Communication . Listening is an im- portant Step of communication. English teaching is aimed at training students' ability to apply the language, listening is the basic and the most direct link in acquiring information. Besides, Having a good listening not only can meet the social development,but also can meet students' development. So cultivation of Students' listen- ing ability should be put into the first place in the process of Eng- lish teaching.

  1. Essential Methods to Improve Students’ Speaking Ability

    Institute of Scientific and Technical Information of China (English)

    周丽丽

    2015-01-01

    Nowadays,English learning has become more and more important for Chinese student.English is primarily used to communicate with others.From this point,students’ speaking ability should be paid more attention to.This thesis focuses on the effective and specific ways,such as free talk or discussion,duty report and so on,to create a good language surrounding to improve their speaking ability.

  2. Cognitive abilities and creating metaphorical names

    Directory of Open Access Journals (Sweden)

    Avanesyan, Marina O.

    2016-06-01

    Full Text Available The cognitive processing of metaphor creation has been insufficiently investigated. Creating metaphors requires the ability to work in a fantastic, impossible context, using symbolic and associative means to express oneís thoughts. It has been shown recently that intelligence plays an important role in the creation of metaphors, but it is not the main factor in determining their success. The present research explores the roles of conceptual abilities, categorical abilities, and flexibility (as the factor creativity in metaphor creation. Participants (n = 38 young adults were asked to come up with names for three photos, without any special instruction to create metaphors. To classify conceptual abilities we used ìConceptual Synthesisî (M. A. Kholodnaya, 2012; to measure categorical ability we used the subtest ìSimilaritiesî (D. Wechsler, 1955; to identify the role of creativity in the metaphor process we used the test of ìUnusual Usesî (J. P. Guilford, 1960. The creation of complex metaphorical names was associated with a tendency to create highly organized mental structures and to retain them within the general semantic context (r = 0.344, p < 0.05. The tendency to create single-level situational connections was associated with a tendency to give specific names to photos (r = 0.475, p < 0.01. Photographic images proved out to be fruitful stimuli to investigate the processing of visual information. We developed a preliminary classification of names: 1 concrete; 2 situational; 3 abstract; 4 metaphorical (M1 and M2. We identified two types of metaphorical names — perceptual and complex metaphors — that relate to conceptual abilities in different ways. It is inaccurate to speak about a general concept of ìmetaphorical abilitiesî; we should differentiate the psychological mechanisms that lie at their base.

  3. Work ability as prognostic risk marker of disability pension : Single-item work ability score versus multi-item work ability index

    NARCIS (Netherlands)

    Roelen, C.A.M.; Rhenen, van W.; Groothoff, J.W.; Klink, van der J.J.L.; Twisk, W.R.; Heymans, M.W.

    2014-01-01

    Work ability predicts future disability pension (DP). A single-item work ability score (WAS) is emerging as a measure for work ability. This study compared single-item WAS with the multi-item work ability index (WAI) in its ability to identify workers at risk of DP.

  4. Caffeine Ingestion Improves Repeated Freestyle Sprints in Elite Male Swimmers

    Science.gov (United States)

    Goods, Paul S.R.; Landers, Grant; Fulton, Sacha

    2017-01-01

    The purpose of this investigation was to determine the efficacy of a moderate dose of caffeine to improve repeat-sprint performance in elite freestyle sprinters. Nine highly trained male swimmers performed 6 x 75 m freestyle sprints on two occasions 1-h after consuming either 3 mg·kg-1 caffeine (CAF), or placebo, in a cross-over manner. Capillary blood samples for the analysis of blood lactate concentration and pH were collected after the 1st, 3rd, and 5th sprint, while heart rate and perceived exertion (RPE) were collected after every sprint. There was a moderate effect for improved mean sprint time in the CAF condition (0.52 s; 1.3%; d = 0.50). When assessed individually, there was a large effect for improved performance in sprints 3 (1.00 s; 2.5%; d = 1.02) and 4 (0.84 s; 2.1%; d = 0.84) in CAF compared to placebo, with worthwhile performance improvement found for each of the first 5 sprints. There was a significant treatment effect for higher blood lactate concentration for CAF (p = 0.029), and a significant treatment*time effect for reduced pH in the CAF condition (p = 0.004). Mean heart rate (167 ± 9 bpm vs 169 ± 7 bpm) and RPE (17 ± 1 vs 17 ± 1) were not different between placebo and CAF trials, respectively. This investigation is the first to demonstrate enhanced repeat-sprint ability in swimmers following acute caffeine ingestion. It appears likely that the combination of a moderate dose of caffeine (3-6 mg·kg-1) with trained athletes is most likely to enhance repeat-sprint ability in various athletic populations; however, the exact mechanism(s) for an improved repeat-sprint ability following acute caffeine ingestion remain unknown. Key points A moderate dose of caffeine (3 mg·kg-1) ingested 1 h before a repeat-sprint freestyle set significantly improves mean sprint time in elite swimmers. The combination of at least a moderate dose of caffeine (>3 mg·kg-1) with trained athletes appears the most likely to result in ergogenic benefit to anaerobic

  5. Development of Writing Ability in English

    Institute of Scientific and Technical Information of China (English)

    赵光存

    2009-01-01

    The Guiding principle for junior English teaching points out: "The aim of junior English teaching is to give the students basic training on how to listen, speak, read and write, to cultivate the students' primary ability of using English."[1]Therefore, writing in English is one of the most important contents and requirements of junior English teaching. Since 1998, the junior students have been required to demonstrate their writing ability by writing an 80-word passage, which should be very accurate, coherent, and fluent.So "the middle school teachers must encourage the students to learn to make simple sentences with the vocabulary, grammar, sentence patterns and to write simple passages, letters, e-mails, notes, notices after the styles and models which have been learned." [2] English, as a most useful language and a most widely used communication means, is very important. The students must acquire the ability of speaking and writing and their all-round ability should be developed.So I write this thesis to discuss and make a research on how to develop and improve the junior students' writing ability in English.

  6. Paramedics’ Ability to Perform Drug Calculations

    Directory of Open Access Journals (Sweden)

    Eastwood, Kathyrn J

    2009-11-01

    Full Text Available Background: The ability to perform drug calculations accurately is imperative to patient safety. Research into paramedics’ drug calculation abilities was first published in 2000 and for nurses’ abilities the research dates back to the late 1930s. Yet, there have been no studies investigating an undergraduate paramedic student’s ability to perform drug or basic mathematical calculations. The objective of this study was to review the literature and determine the ability of undergraduate and qualified paramedics to perform drug calculations.Methods: A search of the prehospital-related electronic databases was undertaken using the Ovid and EMBASE systems available through the Monash University Library. Databases searched included the Cochrane Central Register of Controlled Trials (CENTRAL, MEDLINE, CINAHL, JSTOR, EMBASE and Google Scholar, from their beginning until the end of August 2009. We reviewed references from articles retrieved.Results: The electronic database search located 1,154 articles for review. Six additional articles were identified from reference lists of retrieved articles. Of these, 59 were considered relevant. After reviewing the 59 articles only three met the inclusion criteria. All articles noted some level of mathematical deficiencies amongst their subjects.Conclusions: This study identified only three articles. Results from these limited studies indicate a significant lack of mathematical proficiency amongst the paramedics sampled. A need exists to identify if undergraduate paramedic students are capable of performing the required drug calculations in a non-clinical setting.[WestJEM. 2009;10:240-243.

  7. Methods for Evaluation of Some Psychomotor Abilities

    Directory of Open Access Journals (Sweden)

    Dragan Krivokapić

    2016-06-01

    Full Text Available For estimation of psychomotor and sensor abilities different kinds of tests are used in the form of devices representing different technical devices which help examining sensomotor and psychomotor functions in certain conditions, as well as more complex motor abilities and skills that depend on CNS characteristics, vegetative nervous system and other functional systems and body states. These devices can be used for examining some parameters of psychomotor functions-such as speed of reaction through reactiometer or devices for examining sensor abilities-such as audiometer, ortoriter, color tests etc. In the scope of examining psychomotor skills and abilities, frequently used are different kinds of tests in the forms of devices serving for measuring ocultomotor coordination-such as Omega and Sinusoida, then Tumer`s device for measuring coordination and dissociation of hands` movements with visible control, O-Conor`s dexterimeter and Medeo`s dexterimeter-used for examining dexterity of fingers, Tremometer for examining hand stability and preciseness of movements, Minesota test for examining dexterity of hands and taping tests like “paper-pen” for examining speed and accuracy of simple movements. For examining more complex sensomotor abilities or different motor skills, special tests are used in the form of simulator, simulator and different technical devices, adjusted to specific sports situation. This category of tests includes different kinds of simulators and simulators used for examining certain aspects of sports activity.

  8. Cognitive ability and the demand for redistribution.

    Directory of Open Access Journals (Sweden)

    Johanna Mollerstrom

    Full Text Available Empirical research suggests that the cognitively able are politically more influential than the less able, by being more likely to vote and to assume leadership positions. This study asks whether this pattern matters for public policy by investigating what role a person's cognitive ability plays in determining his preferences for redistribution of income among citizens in society. To answer this question, we use a unique Swedish data set that matches responses to a tailor-made questionnaire to administrative tax records and to military enlistment records for men, with the latter containing a measure of cognitive ability. On a scale of 0 to 100 percent redistribution, a one-standard-deviation increase in cognitive ability reduces the willingness to redistribute by 5 percentage points, or by the same amount as a $35,000 increase in mean annual income. We find support for two channels mediating this economically strong and statistically significant relation. First, higher ability is associated with higher income. Second, ability is positively correlated with the view that economic success is the result of effort, rather than luck. Both these factors are, in turn, related to lower demand for redistribution.

  9. Paramedics’ Ability to Perform Drug Calculations

    Science.gov (United States)

    Eastwood, Kathryn J; Boyle, Malcolm J; Williams, Brett

    2009-01-01

    Background: The ability to perform drug calculations accurately is imperative to patient safety. Research into paramedics’ drug calculation abilities was first published in 2000 and for nurses’ abilities the research dates back to the late 1930s. Yet, there have been no studies investigating an undergraduate paramedic student’s ability to perform drug or basic mathematical calculations. The objective of this study was to review the literature and determine the ability of undergraduate and qualified paramedics to perform drug calculations. Methods: A search of the prehospital-related electronic databases was undertaken using the Ovid and EMBASE systems available through the Monash University Library. Databases searched included the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, CINAHL, JSTOR, EMBASE and Google Scholar, from their beginning until the end of August 2009. We reviewed references from articles retrieved. Results: The electronic database search located 1,154 articles for review. Six additional articles were identified from reference lists of retrieved articles. Of these, 59 were considered relevant. After reviewing the 59 articles only three met the inclusion criteria. All articles noted some level of mathematical deficiencies amongst their subjects. Conclusions: This study identified only three articles. Results from these limited studies indicate a significant lack of mathematical proficiency amongst the paramedics sampled. A need exists to identify if undergraduate paramedic students are capable of performing the required drug calculations in a non-clinical setting. PMID:20046240

  10. Cognitive abilities, sociocultural background and academic achievement.

    Science.gov (United States)

    Diniz, António; Dias Pocinho, Margarida; Silva Almeida, Leandro

    2011-11-01

    The influence of students' sociocultural background on academic achievement is a well established fact. Research also points out that sociocultural background is related to students' cognitive abilities and these have an effect on their academic achievement. However, the mediator role of cognitive abilities on the relationship between sociocultural background and academic achievement is less well known. A structural equation model that represents these relationships was tested in a sample (N= 728) of Portuguese junior high school students. Multigroup analysis of the model showed the importance of the cognitive ability mediation effect between sociocultural background and academic achievement in the 7th and 9th grades, but not in the 8th grade. This difference may be the result of the academic transition experienced in the 7th and 9th grades in the Portuguese educational system, which requires parents' higher involvement in school.

  11. Human voice recognition depends on language ability.

    Science.gov (United States)

    Perrachione, Tyler K; Del Tufo, Stephanie N; Gabrieli, John D E

    2011-07-29

    The ability to recognize people by their voice is an important social behavior. Individuals differ in how they pronounce words, and listeners may take advantage of language-specific knowledge of speech phonology to facilitate recognizing voices. Impaired phonological processing is characteristic of dyslexia and thought to be a basis for difficulty in learning to read. We tested voice-recognition abilities of dyslexic and control listeners for voices speaking listeners' native language or an unfamiliar language. Individuals with dyslexia exhibited impaired voice-recognition abilities compared with controls only for voices speaking their native language. These results demonstrate the importance of linguistic representations for voice recognition. Humans appear to identify voices by making comparisons between talkers' pronunciations of words and listeners' stored abstract representations of the sounds in those words.

  12. Construct ability Improvement for Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dae Soo; Lee, Jong Rim; Kim, Jong Ku [Korea Electric Power Research Institute, Taejon (Korea, Republic of)

    1997-12-31

    The purpose of this study was to identify methods for improving the construct ability of nuclear power plants. This study reviewed several references of current construction practices of domestic and overseas nuclear plants in order to identify potential methods for improving construct ability. The identified methods for improving construct ability were then evaluated based on the applicability to domestic nuclear plant construction. The selected methods are expected to reduce the construction period, improve the quality of construction, cost, safety, and productivity. Selection of which methods should be implemented will require further evaluation of construction modifications, design changes, contract revisions. Among construction methods studied, platform construction methods can be applied through construction sequence modification without significant design changes, and Over the Top construction method of the NSSS, automatic welding of RCL pipes, CLP modularization, etc., are considered to be applied after design modification and adjustment of material lead time. (author). 49 refs., figs., tabs.

  13. ENHANCING WRITING ABILITY THROUGH IDEA LISTING TECHNIQUE

    Directory of Open Access Journals (Sweden)

    M. Zaini Miftah

    2015-05-01

    Full Text Available The study is aimed at developing the Idea Listing Technique (ILT to enhance the students‟ writing ability. The Classroom Action Research was applied in this study. The subjects of the study were 31 students, the students taking the course of Writing II, of the third semester of English Department of one State Islamic College at Palangka Raya, Indonesia, in the 2012/2013 academic year. The findings show that the implementation of ILT can enhance the students‟ ability in writing expository paragraph. It is indicated by the enhancements of the percentage of the students achieving the score greater than or equal to C (60-69, and of the percentage of their involvement in the writing activities during the implementation of ILT in Cycle I and II. Thus, the enhancement of the students‟ ability in writing expository paragraph can be reached but it should follow the appropriate procedures of the implementation of ILT having been developed.

  14. Creativity, synthetic intelligence and high ability

    Directory of Open Access Journals (Sweden)

    Marta Sainz

    2010-04-01

    Full Text Available The objective of this study is to analyze the construct of creativity and its relationship with high ability, presenting different definitions, assessment tools and strategies to encourage their development in the school context. The paper is structured into five sections: firstly, we define the concept of creativity. Secondly, we present the most relevant instruments used in the analysis of high ability students’ creativity. Thirdly, we look into several studies on creativity and high abilitiy, highlighting the main limitations of the research carried out. Fourthly, we present principles and strategies in order to foster creativity in the school context. Finally, some conclusions are drawn on the relationship between creativity and high ability.

  15. Assessing functional ability in older patients

    DEFF Research Database (Denmark)

    Nielsen, Louise Møldrup; Maribo, Thomas; Nielsen, Hanne Grethe

    2014-01-01

    different settings: the local hospital and the municipality. Results: Focus group interviews showed that health professionals in the hospital and the municipality expressed the need for an observation-based tool to predict and guide decisions about the rehabilitation needs of older patients. Participants...... from the hospital expressed a need for a fast and simple screening tool to identify those in need of further rehabilitation and care after discharge. Participants from the municipality expressed a need for a more detailed assessment tool to capture information about patients’ ability to perform daily...... to administer, to assess the quality of functional ability and predict the need for rehabilitation. The different context (hospital or primary care) seems to influence the way health professionals perceive the need for assessment of functional ability in older patients....

  16. Grade Inflation Rates among Different Ability Students

    Directory of Open Access Journals (Sweden)

    Stephanie Mc Spirit

    1999-09-01

    Full Text Available This study compares grade inflation rates among different ability students at a large, open admissions public University. Specifically, this study compares trends in graduating grade point average (GPA from 1983 to 1996 across low, typical and higher ability students. This study also tests other explanations for increases in graduating GPA. These other explanations are changes in 1 ACT score 2 gender 3 college major and 4 vocational programs. With these other explanations considered, regression results still report an inflationary trend in graduating GPA. Time, as measured by college entry year, is still a significant positive predictor of GPA. More directly, comparisons of regression coefficients reveal lower ability students as experiencing the highest rate of grade increase. Higher grade inflation rates among low aptitude students suggest that faculty might be using grades to encourage learning among marginal students.

  17. ACCREDITATION FOR TECHNICAL ABILITIES INCLUDING COMPUTER SKILLS

    Directory of Open Access Journals (Sweden)

    Halit Hami OZ

    2013-01-01

    Full Text Available Sector Skills are defined by state-sponsored, employer-led organizations that cover specific economic sectors in the European Union and other countries in the world to reduce skills gaps and shortages, improve productivity, boost the skills of their sector workforces and improve learning supply. The accreditation and registration systems used by professional bodies raise the profile of the profession. In many countries including the European Union, professional associations are beginning to accept practice-based accreditation, generally as an alternative to their mainstream systems. Besides studying the certain agencies in the European Union for assessing/accreditating practical abilities , Accreditation for practical abilities of Information Communication Technology and Business Management/Language domains developed by Accreditation Council for Practical abilities are also studied in detail as an example to establish a similar agency in Turkey.

  18. Emotional Intelligence and EFL Students’ Translation Ability

    Directory of Open Access Journals (Sweden)

    Samaneh Moghimi

    2013-05-01

    Full Text Available Emotional Intelligence is a challenging topic in the area of language research. Among other factors that might manipulate translators’ mind, their Emotional Intelligence level might be an influential element, too. The present research focused on examining the relationship between emotional intelligence and the students’ translation ability. It was carried out among 59 translation students in the Payam-Noor University in Iran, Mazandaran. After homogenizing the sample, the sample size was reduced to 32. The participants were required to translate some paragraphs of the short story 'A rose for Emily' and answer the Bar-On EQ-I questionnaire (1997. The results indicated that there was no relationship between EQ and the learners’ translation ability but some of the main subscales of emotional intelligence (i.e., problem solving, happiness, and flexibility had statistically weak relationship with the learners’ translation ability. The results also showed that the combination of EQ and gender were positively correlated.

  19. Extracurricular enrichment workshops for high ability students

    Directory of Open Access Journals (Sweden)

    Ángela Rojo

    2010-04-01

    Full Text Available The aim of this article is to analyze and explain attention to diversity measures for high ability (gifted and talented students. The model, developed in the Spanish region of Murcia, is based on cognitive psychology and aims to encourage thinking skills. The program is developed as a curriculum extension and the interests, motivations and abilities of children have been considered once these were identified. The article offers a theoretical approach, a set of objectives, and some of the activities that have been done with students.

  20. Musical Activity Tunes Up Absolute Pitch Ability

    DEFF Research Database (Denmark)

    Dohn, Anders; Garza-Villarreal, Eduardo A.; Ribe, Lars Riisgaard

    2014-01-01

    Absolute pitch (AP) is the ability to identify or produce pitches of musical tones without an external reference. Active AP (i.e., pitch production or pitch adjustment) and passive AP (i.e., pitch identification) are considered to not necessarily coincide, although no study has properly compared...... that APs generally undershoot when adjusting musical pitch, a tendency that decreases when musical activity increases. Finally, APs are less accurate when adjusting the pitch to black key targets than to white key targets. Hence, AP ability may be partly practice-dependent and we speculate that APs may...