Relationships between repeated sprint testing, speed, and endurance

Repeated sprint testing is gaining popularity in team sports, but the methods of data analysis and relationships to speed and endurance qualities are not well described. We compared three different methods for analyzing repeated sprint test results, and we quantified relationships between repeated sprints, short sprints, and endurance test scores. Well-trained male junior Australian Football players (n = 60, age 18.1 +/- 0.4 years, height 1.88 +/- 0.07 m, mass 82.0 +/- 8.1 kg; mean +/- SD) completed a 6 x 30-m repeated sprint running test on a 20-second cycle, a 20-m sprint test (short sprint), and the 20-m multistage shuttle run for endurance. Repeated sprint results were evaluated in three ways: total time for all six sprints (TOTAL), percent change from predicted times (PRED) from the fastest 30-m sprint time, and percent change from first to last sprint (CHANGE). We observed a very large decrement (CHANGE 6.3 +/- 0.7%, mean +/- 90% confidence limits) in 30-m performance from the first to last sprint (4.16 +/- 0.10 to 4.42 +/- 0.11 seconds, mean +/- SD). Results from TOTAL were highly correlated with 20-m sprint and 20-m multistage shuttle run tests. Performance decrements calculated by PRED were highly correlated with TOTAL (r = 0.91), but neither method was directly comparable with CHANGE (r = -0.23 and r = 0.12 respectively). TOTAL was moderately correlated with fastest 20-m sprint time (r = 0.66) but not the 20-m multistage shuttle run (r = -0.20). Evaluation of repeated sprint testing is sensitive to the method of data analysis employed. The total sprint time and indices of the relative decrement in performance are not directly interchangeable. Repeated sprint ability seems more related to short sprint qualities than endurance fitness.     

The reliability and validity of fatigue measures during short-duration maximal-intensity intermittent cycling

The purpose of the present study was to assess the reliability and validity of fatigue measures, as derived from 4 separate formulae, during tests of repeat sprint ability. On separate days over a 3-week period, 2 groups of 7 recreationally active men completed 6 trials of 1 of 2 maximal (20 x 5 seconds) intermittent cycling tests with contrasting recovery periods (10 or 30 seconds). All trials were conducted on a friction-braked cycle ergometer, and fatigue scores were derived from measures of mean power output for each sprint. Apart from formula 1, which calculated fatigue from the percentage difference in mean power output between the first and last sprint, all remaining formulae produced fatigue scores that showed a reasonably good level of test-retest reliability in both intermittent test protocols (intraclass correlation range: 0.78-0.86; 95% likely range of true values: 0.54-0.97). Although between-protocol differences in the magnitude of the fatigue scores suggested good construct validity, within-protocol differences highlighted limitations with each formula. Overall, the results support the use of the percentage decrement score as the most valid and reliable measure of fatigue during brief maximal intermittent work.     

The effects of a constant sprint-to-rest ratio and recovery mode on repeated sprint performance

It is unclear if a constant sprint-to-rest ratio allows full performance recovery between repeated sprints over different distances. This is important for the development of sprint-training programs. Additionally, there is conflicting evidence on whether active recovery enhances sprint performance. Three repeated sprint protocols were used (22 × 15, 13 × 30, and 8 × 50 m), with each having an active and passive recovery. Each trial was conducted with an initial sprint-to-rest ratio of 1:10. Repeated sprints were analyzed by comparing the first sprint to the last sprint. For the 15-m trials, there were no significant main effects for recovery or time and no significant interaction. For the 30-m trials, there was no main effect for recovery, but a main effect for time (F[1,10] = 15.995, p = 0.003; mean difference = 0.20 seconds, 95% confidence interval [CI] = 0.09-0.31 seconds, d = 1.4 [large effect]). There was no interaction of recovery and time in the 30-m trials. For the 50-m trials, there was no main effect for recovery, but a main effect for time (F[1,10] = 34.225, p = 0.0002; mean difference = 0.39 seconds, 95% CI = 0.24-0.55 seconds, d = 1.3 [large effect]). There was no interaction of recovery and time in the 50-m trials. The results demonstrate that a 1:10 sprint-to-rest ratio allows full performance recovery between 15-m sprints, but not between sprints of 30 or 50 m, and that recovery mode did not influence repeated sprint performance.     

Role of energy systems in two intermittent field tests in women field hockey players

The energetics of 2 field tests that reflect physical performance in intermittent sports (i.e., the Interval Shuttle Sprint Test [ISST] and the Interval Shuttle Run Test [ISRT]) were examined in 21 women field hockey players. The ISST required the players to perform 10 shuttle sprints starting every 20 seconds. During the ISRT, players alternately ran 20-m shuttles for 30 seconds and walked for 15 seconds with increasing speed. Anaerobic and aerobic power tests included Wingate cycle sprints and a .V(O2)max cycle test, respectively. Based on correlation and regression analyses, it was concluded that for the ISST, anaerobic energetic pathways contribute mainly to energy supply for peak sprint time, while aerobic energetic pathways also contribute to energy supply for total sprint time. Energy during the ISRT is supplied mainly by the aerobic energy system. Depending on the aspect of physical performance a coach wants to determine, the ISST or ISRT can be used.     

Effect of recovery mode on repeated sprint ability in young basketball players

The aim of this study was to examine the effect of recovery mode on repeated sprint ability in young basketball players. Sixteen basketball players (age, 16.8 +/- 1.2 years; height, 181.3 +/- 5.7 cm; body mass, 73 +/- 10 kg; VO2max, 59.5 +/- 7.9 mL x kg(-1) x min(-1)) performed in random order over 2 separate occasions 2 repeated sprint ability protocols consisting of 10 x 30-m shuttle run sprints with 30 seconds of passive or active (running at 50% of maximal aerobic speed) recovery. Results showed that fatigue index (FI) during the active protocol was significantly greater than in the passive condition (5.05 +/- 2.4, and 3.39 +/- 2.3, respectively, p < 0.001). No significant association was found between VO2peak and FI and sprint total time (TT) in either repeated sprint protocols. Blood lactate concentration at 3 minutes post exercise was not significantly different between the 2 recovery conditions. The results of this study show that during repeated sprinting, passive recovery enabled better performance, reducing fatigue. Consequently, the use of passive recovery is advisable during competition in order to limit fatigue as a consequence of repeated high intensity exercise.     

Validity of a squash-specific test of multiple-sprint ability

We examined the validity and reproducibility of a squash-specific multiple-sprint test. Eight male squash and 8 male soccer players performed Baker's 8 × 40-m sprints and a squash-specific-multiple-sprint test on separate days. The sum of individual sprint times in each test was recorded. Six squash and 6 soccer players repeated the tests 7 days later to assess reproducibility using intraclass correlation. In addition, 2 England Squash coaches independently ranked the squash players using knowledge of the player and recent performances in local leagues. Performance on the squash-specific (r = 0.97 and 0.90) and Baker's test (r = 0.95 and 0.83) was reproducible in squash and soccer players, respectively, and did not differ on Baker's test (mean ± SD 72.9 ± 3.9 and 72.9 ± 2.8 seconds for squash and soccer players, p = 0.969, effect size = 0.03). Squash players (232 ± 32 seconds) outperformed soccer players (264 ± 14 seconds) on the squash-specific test (p = 0.02, effect size = 1.39). Performance on Baker's and the squash-specific test were related in squash players (r = 0.98, p < 0.001) but not in soccer players (r = -0.08, p = 0.87). Squash-player rank correlated with performance on the squash-specific (ρ = 0.79, p = 0.02) but not the Baker's test (ρ = 0.55, p = 0.16). The squash-specific test discriminated between groups with similar non-sport-specific multiple-sprint ability and in squash players. In conjunction with the relationship between test performances, the results suggest that the squash-specific test is a valid and reproducible measure of multiple-sprint ability in squash players and could be used for assessing and tracking training-induced changes in multiple-sprint ability.     

The effects of enforced, rapid deceleration on performance in a multiple sprint test

The nature of multiple sprint sports such as soccer, hockey, and rugby is such that deceleration plays an important part in the movement patterns of players during a game and training. The purpose of this study was to investigate the effect of deceleration on fatigue during repeated sprint efforts. A group of 18 elite field hockey players (all men) performed a running repeated sprint ability test (6 x 40 m using maximal effort and departing every 30 seconds). In one condition, there was no deceleration zone, and in the second condition, the test had a deceleration component (rapid deceleration to a stop within 6 m of the end of each sprint). Sprint times under each condition were compared using a repeated-measures analysis of variance. No significant difference was seen between the 2 conditions for mean sprint times (p > 0.05) or for the mean fatigue index (p > 0.05). However, results showed a divergent trend, and further analysis extrapolating the data for an increased number of sprints showed that a significant difference (p < 0.05) would have been seen at the 11th sprint. Although this study found that the deceleration zone had little effect on the 6-sprint protocol, it was clear that the deceleration component would have shown an effect, giving rise to greater fatigue and slower sprint times, if the number of sprints had been increased. The implications are that deceleration training should be introduced into general fitness training programs for those competing in multiple sprint sports.     

Familiarization and reliability of multiple sprint running performance indices

The aims of this study were to evaluate the time-course of the familiarization process associated with a test of multiple sprint running performance and to determine the reliability of various performance indices once familiarization had been established. Eleven physically active men (mean age: 21 +/- 2 years) completed 4 multiple sprint running trials (12 x 30 m; repeated at 35-s intervals) with 7 days between trials. All testing was conducted indoors, and times were recorded by twin-beam photocells. Results revealed no apparent learning effects as evidenced by no significant (p > 0.05) between-trial differences in measures of fastest or mean 30-m sprint time. Within-subject test-retest reliability determined over 4 trials by coefficient of variation (CV) and intraclass correlation coefficient (ICC) showed excellent reliability for measures of fastest and mean sprint times (CV range: 1.34-2.24%; ICC range: 0.79-0.94). Pre- and posttrial blood lactate concentrations showed good reliability when judged in context with typical values (CV range: 12.08-18.21%; ICC range: 0.72-0.78). In contrast, and in line with previous research, fatigue data showed much greater variability (CV: 26.43%; ICC: 0.66). The results of this study suggest that high degrees of test-retest reliability can be obtained in many multiple sprint running indices without the need for prior familiarization.     

The influence of recovery duration on multiple sprint cycling performance

The purpose of this study was to examine the influence of recovery duration on various measures of multiple sprint cycling performance. Twenty-five physically active men completed 2 maximal multiple sprint (20 x 5 seconds) cycling tests with contrasting recovery periods (10 or 30 seconds). The mean +/- SD values for age, height, and body mass were 20.6 +/- 1.5 years, 177.2 +/- 5.4 cm, and 78.2 +/- 8.2 kg, respectively. All tests were conducted on a friction-braked cycle ergometer. Longer (30 seconds) recovery periods resulted in significantly (p < 0.05) higher measures of maximum (approximately 4%) and mean (approximately 26%) power output, the former appearing to result from a potentiation effect during the first few sprints. Thirty-second recovery periods also corresponded with significantly lower measures of fatigue (absolute difference: 16.1%; 95% likely range: 14.1-18.2%), heart rate, respiratory exchange ratio, and oxygen uptake. Blood lactate and ratings of perceived exertion (6-20 scale) increased progressively throughout both protocols and were significantly lower with 30-second recovery periods. The results of this study illustrate the considerable influence of recovery duration on various measures of multiple sprint work. Although the precise mechanisms of this response require further investigation, coaches and sport scientists should consider these findings when attempting to develop or evaluate the performance capabilities of athletes involved in multiple sprint sports.     

Effect of capsaicin supplementation on repeated sprinting performance

Performance in many team sports is partially dependent on the ability to perform repeatedly at high intensity. Previous research demonstrates that capsaicin (CAP) has physiological and metabolic effects that could influence exercise performance and inflammation. The purpose of this study was to investigate the influence of CAP on performance of and the interleukin-6 (IL-6) response to repeated sprints. Nineteen healthy male experienced athletes, age 18-30 years, participated in a placebo (PCB)-controlled, crossover study. During 1 trial, they consumed 3 g·d(-1) cayenne (25.8 mg·d(-1) CAP) and the other a PCB for days. Directly after the supplementation period, they completed a repeated sprint test (RST) consisting of 15 30-m maximal effort sprints on 35-second intervals with sprint times measured via an electronic dual-beam timing system. Fasted blood draws for IL-6 were taken at baseline before supplementation, 45 minute pre-RST, and immediately post-RST. Rate of perceived exertion (RPE), muscle soreness (MS), and gastrointestinal distress (GD) for 5 symptom subscales were measured 1-minute pretest, during, posttest, and 1-minute posttest. The MS was additionally measured for 3-day posttest. Relative to the PCB, CAP significantly increased the sum of ratings of GD symptoms by 6.3-fold. There was no difference between treatments in fastest or mean sprint time, fatigue, IL-6 response, RPE, or MS. In summary, CAP did not influence repeated sprint performance or the IL-6 response but caused substantial GD. The CAP is not recommended for athletes involved in repeated sprinting.     

Effects of sprint duration and exercise: rest ratio on repeated sprint performance and physiological responses in professional soccer players

The purpose of this study was to examine the physiological effects of different sprint repetition protocols on professional footballers. Of particular interest were the abilities of repeated sprint protocols to induce fatigue to an extent observed during competitive soccer. Six professional soccer players were assessed for fatigue rate and physiological responses of heart rate (HR), blood lactate (BLa), and rating of perceived exertion (RPE) during the performance of 4 repeated sprint drills, each totaling a sprint distance of 600 m. The 4 drills used 15- or 40-m sprints with 1:4 or 1:6 exercise: rest ratios. The 15-m sprint drill with 1:4 exercise:rest ratio induced the greatest fatigue (final sprint time 15% greater than initial sprint time) and greatest physiological responses. The 40-m sprint drill using a 1:4 exercise:rest ratio produced similar BLa and HR responses to the 15-m drill (13-14 mmol.L(-1) and 89% HRmax, respectively) but significantly lower RPE (mean +/- SD: 17.1 +/- 0.4 vs. 18.8 +/- 0.4, p < 0.05) and fatigue rates (11.1 vs. 15.0%, p < 0.01). Both sprint distance and exercise:rest ratio independently influenced fatigue rate, with the 15-m sprint distance and the 1:4 exercise:rest ratio inducing significantly (p < 0.01) greater fatigue than the 40-m sprint distance and the 1:6 exercise:rest ratio. The magnitude of fatigue during the 40- x 15-m sprint drill using a 1:6 exercise:rest ratio was 7.5%, which is close to the fatigue rate previously reported during actual soccer play. The present study is the first to examine both variations in sprint distances and rest ratios simultaneously, and the findings may aid the design of repeated sprint training for soccer.     

Repeated-sprint ability and aerobic fitness

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 < 0.01, n = 19) with the UMTT (continuous forward running) suggests that some aerobic tests better disclose the importance of aerobic fitness for RSA and that aerobic power is not the sole determinant of RSA. However, neither strength nor vertical jumping power was correlated to the RSA fatigue indices. Subjects with greater MAS were able to maintain almost constant level of speed throughout series of 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.     

Aerobic and anaerobic correlates of multiple sprint cycling performance

The aims of this study were to examine (a) the relationship between maximal oxygen uptake (VO(2)max) and several performance indices of multiple sprint cycling; (b) the relationship between maximal accumulated oxygen deficit (MAOD) and those same performance indices; and (c) the influence of recovery duration on the magnitude of those relationships. Twenty-five physically active men completed a VO(2)max test, a MAOD test, and 2 maximal intermittent (20 x 5 seconds) sprint cycling tests with contrasting recovery periods (10 seconds or 30 seconds). Mean +/- SD for age, height, and body mass were 20.6 +/- 1.5 years, 177.2 +/- 5.4 cm, and 78.2 +/- 8.2 kg, respectively. All tests were conducted on a friction-braked cycle ergometer with subsequent data normalized for body mass. Moderate (0.3 < or = r < 0.5) positive correlations were observed between power output data and MAOD (range, 0.31-0.46; 95% confidence limits, -0.10 to 0.72). Moderate to large positive correlations also were observed between power output data and VO(2)max, the magnitude of which increased as values were averaged across all sprints (range, 0.45-0.67; 95% confidence limits 0.07-0.84). Correlations between fatigue and VO(2)max were greater in the intermittent protocol with 30-second recovery periods (r = -0.34; 95% confidence limits, 0.06 to -0.65). The results of this study reflect the complex energetics associated with multiple sprint work. Though the findings add support to the idea that multiple sprint sports demand a combination of speed and endurance, further longitudinal research is required to confirm the relative importance of these parameters.     

Effect of creatine supplementation on intermittent sprint running performance in highly trained athletes

This study examined the impact of short-term (7-day), high-dose (0.35 g.kg(-1).d(-1)) oral creatine monohydrate supplementation (CrS) on single sprint running performance (40 m, <6 seconds) and on intermittent sprint performance in highly trained sprinters. Nine subjects completed the double-blind cross-over design with 2 supplementation periods (placebo and creatine) and a 7-week wash-out period. A test protocol consisting of 40-m sprint runs was performed, and running velocity was continuously recorded over the total distance. The maximal sprint performance, the relative degree of fatigue at the end of intermittent sprint exercise (6 x 40 m, 30-second rest interval), as well as the degree of recovery (120-second passive rest) remained unchanged following CrS. There were no significant changes related to CrS in absolute running velocity at any distance between start and finish (40 m). It was concluded that no ergogenic effect on single or repeated 40-m sprint times with varying rest periods was observed in highly trained athletes.     

Performance and fatigue during repeated sprints: what is the appropriate sprint dose?

When testing the ability of sportsmen to repeat maximal intensity efforts, or when designing specific training exercises to improve it, fatigue during repeated sprints is usually investigated through a number of sprints identical for all subjects, which induces a high intersubject variability in performance decrement in a typical heterogeneous group of athletes (e.g., team sport group, students, and research protocol volunteers). Our aim was to quantify the amplitude of the reduction in this variability when individualizing the sprint dose, that is, when requiring subjects to perform the number of sprints necessary to reach a target level of performance decrement. Fifteen healthy men performed 6-second sprints on a cycle ergometer with 24 seconds of rest until exhaustion or until 20 repetitions in case no failure occurred. Peak power output (PPO) was measured and a fatigue index (FI) computed. The variability in PPO decrement was compared between the 10th sprint and the sprint at which subject reached the target FI of 10%. Individual FI values after the 10th sprint were 14.6 ± 6.9 vs. 11.1 ± 1.2%, when individualizing the sprint dose, which corresponded to coefficients of interindividual variability of ～47.3 and ～10.8%, respectively. Individualizing the sprint dose substantially reduced intersubject variability in performance decrement, enabling a more standardized state of fatigue in repeated-sprints protocols designed to induce fatigue and test or train this specific repeated-sprint ability in a heterogeneous group of athletes. A direct feedback on the values of performance parameters is necessary between each sprint for the experimenter to set this individualized sprint dose.     

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

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. However, because the sample size in this study is 20 participants, the results are valid only for those who took part in this study. Therefore, we advice to use repeated sprint training similar to the one in this study only in periods where the players have no speed training included in their program. Furthermore, the participants in this study should probably trained strength, however, benefits were observed even without strength training is most likely to be caused by the training specificity.     

Effect of pre-performance lower-limb massage on thirty-meter sprint running

Massage is a commonly utilized therapy within sports, frequently intended as an ergogenic aid prior to performance. However, evidence as to the efficacy of massage in this respect is lacking, and massage may in some instances reduce force production. The aim of this study was to investigate the effect of massage on subsequent 30-m sprint running performance. Male university level repeat sprint sports players volunteered for the study (n = 37). After each of 3 treatment conditions, subjects completed a standardized warm-up followed by three 30-m sprint trials in a counterbalanced crossover design. Treatment conditions were 15 minutes of lower-limb massage (M), 15 minutes of placebo ultrasound (PU), and rest (R). Thirty-meter sprint times were recorded (including 10-m split times) for the 3 trials under each condition. Best times at 10 m (M: 1.85 +/- 0.09 seconds, PU: 1.84 +/- 0.11 seconds, R: 1.83 +/- 0.10 seconds) and 30 m (M: 4.41 +/- 0.27 seconds, PU: 4.39 +/- 0.28 seconds, R: 4.39 +/- 0.28 seconds) were not significantly different (p > 0.05). There was no significant treatment, trial, or interaction effect for 10- or 30-m sprint times (p > 0.05). No difference was seen in the location of subjects' best times across the 3 trials (p > 0.05). Relative to placebo or control, the results of this study showed that a controlled 15-minute lower-limb massage administered prior to warm-up had no significant effect on subsequent 30-m sprint performance. Massage remains indicated prior to performance where other benefits, such as reduced muscle spasm and psychological stress, might be served to the athlete.     

Effect of instantaneous performance feedback during 6 weeks of velocity-based resistance training on sport-specific performance tests

The purpose of this study was to investigate the effect of instantaneous performance feedback (peak velocity) provided after each repetition of squat jump exercises over a 6-week training block on sport-specific performance tests. Thirteen professional rugby players were randomly assigned to 1 of 2 groups, feedback (n = 7) and non-feedback (n = 6). Both groups completed a 6-week training program (3 sessions per week) comprising exercises typical of their normal preseason conditioning program. Squat jumps were performed in 2 of the 3 sessions each week during which both groups performed 3 sets of 3 concentric squat jumps using a barbell with an absolute load of 40 kg. Participants in group 1 were given real-time feedback on peak velocity of the squat jump at the completion of each repetition using a linear position transducer and customized software, whereas those in group 2 did not receive any feedback. Pre and posttesting consisted of vertical jump, horizontal jump, and 10-/20-/30-m timed sprints. The relative magnitude (effect size) of the training effects for all performance tests was found to be small (0.18-0.28), except for the 30-m sprint performance, which was moderate (0.46). The probabilities that the use of feedback during squat jump training for 6 weeks was beneficial to increasing performance of sport-specific tests was 45% for vertical jump, 65% for 10-m sprints, 49% for 20-m sprints, 83% for horizontal jump, and 99% for 30-m sprints. In addition to improvements in the performance of sport-specific tests, suggesting the potential for greater adaptation and larger training effects, the provision of feedback may also be used in applications around performance targets and thresholds during training.     

Complex training in ice hockey: the effects of a heavy resisted sprint on subsequent ice-hockey sprint performance

The aim of the study was to investigate the acute effect of a heavy resisted sprint when used as a preload exercise to enhance subsequent 25-m on-ice sprint performance. Eleven competitive ice-hockey players (mean ± SD: Age = 22.09 ± 3.05 years; Body Mass = 83.47 ± 11.7 kg; Height = 1.794 ± 0.060 m) from the English National League participated in a same-subject repeated-measures design, involving 2 experimental conditions. During condition 1, participants performed a 10-second heavy resisted sprint on ice. Condition 2 was a control, where participants rested. An electronically timed 25-m sprint on ice was performed before and 4 minutes after each condition. The results indicated no significant difference (p = 0.176) between pre (3.940 + 0.258 seconds) and post (3.954 + 0.261 seconds) sprint times in the control condition. The intervention condition, however, demonstrated a significant 2.6% decrease in times (p = 0.02) between pre (3.950 + 0.251 seconds) and post (3.859 + 0.288 seconds) test sprints. There was also a significant change (p = 0.002) when compared to the times of the control condition. These findings appear to suggest that the intensity and duration of a single resisted sprint in this study are sufficient to induce an acute (after 4 minutes of rest) improvement in 25-m sprint performance on ice. For those athletes wishing to improve skating speed, heavy resisted sprints on ice may provide a biomechanically suitable exercise for inducing potentiation before speed training drills.     

Repeated-sprint and effort ability in rugby league players

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.