Search

Purpose: High-intensity long-interval training (long-HIIT; interval ≥ 1 min; intensity 85–100% of maximal oxygen uptake [V̇O2max]) is often applied for cardiorespiratory adaptations; however, long-HIIT can also challenge the anaerobic and neuromuscular systems. Therefore, this study aimed to investigate the effects of 4-week long-HIIT (11 sessions) on anaerobic capacity, repeated sprint ability (RSA), and neuromuscular function. Methods: Twenty active men (V̇O2max: 44.8 ± 5.3 mL.kg−1.min−1) performed an incremental running test (TINC), a supramaximal test consisting in running until the task failure at 115% of maximum velocity achieved in TINC (VINC) for anaerobic capacity determination, and an RSA test (2 × 6 × 35-m all-out sprints) pre- and post-HIIT. Before and after RSA, the neuromuscular function was assessed with counter movement jumps (CMJ) and knee extensors maximal isometric voluntary contractions (MVC) with femoral nerve electrical stimulation. Long-HIIT consisted of 10 × 1-min runs at 90% of VINC with 1-min recovery. Results: Long-HIIT induced significant increase in V̇O2max (P = 0.0001). Although anaerobic capacity did not change significantly, 60% of the participants improved above the smallest worthwhile change (0.2 × standard deviation of pre-HIIT). The changes in sprint performance over RSA was significantly less post-HIIT than pre (P = 0.01). RSA induced significant drop of MVC, high frequency doublet, voluntary activation and CMJ performance at pre- and post-HIIT (P < 0.01); however, the percentage of reduction from rest to fatigued conditions were not significantly altered at post-HIIT compared to Pre. Conclusions: 11 sessions of long-HIIT over 4-week improved maximal aerobic power but not anaerobic capacity, and neuromuscular function. Yet, neuromuscular fatigue was similar despite greater speeds reached during RSA. [ABSTRACT FROM AUTHOR]

Individual variations in peripheral oxygen saturation (SpO2) during repeated sprints in hypoxia and their impact on exercise performance remain unclear despite fixed external hypoxic stimuli (inspired oxygen fraction: FiO2). This study examined SpO2 individual variations during repeated sprints in hypoxia and their impact on exercise performance. Thirteen highly-trained sprint runners performed 10 × 10-s cycle sprints with 30-s passive recoveries in normobaric hypoxia (FiO2: 0.150). Mean power output (MPO), post-sprint SpO2, and heart rate for each sprint were assessed. Sprint decrement score (Sdec), evaluating fatigue development, was calculated using MPO variables. Participants were categorized into a high saturation group (HiSat, n =7) or a low saturation group (LowSat, n = 6) based on their mean post-sprint SpO2 (measured 10-15 s after each sprint). Individual mean post-sprint SpO2 ranged from 91.6% to 82.2%. Mean post-sprint SpO2 was significantly higher (P < 0.001, d = 1.54) in HiSat (89.1% ± 1.5%) than LowSat (84.7% ± 1.6%). A significantly larger decrease in Sdec (P = 0.008, d = 1.68) occurred in LowSat (-22.3% ± 2.3%) compared to HiSat (-17.9% ± 2.5%). MPO (P = 0.342 d = 0.55) and heart rate (P = 0.225 d = 0.67) did not differ between groups. There was a significant correlation (r = 0.61; P = 0.028) between SpO2 and Sdec. In highlytrained sprint runners, individual responses to hypoxia varied widely and significantly affected repeated sprint ability, with greater decreases in SpO2 associated with larger performance alterations (i.e., larger decrease in Sdec). [ABSTRACT FROM AUTHOR]

Abstract Sprint interval training (SIT) is a potent exercise strategy to enhance athletes’ anaerobic capacity in a time-efficient manner. This study aimed to investigate the impact of low-volume, court-based SIT on the anaerobic capacity and sport-specific performance in competitive tennis players. Twenty-four competitive collegiate tennis players were randomly assigned to either the SIT group (n = 12; three sessions per week of court-based repeated-sprint training) or the traditional endurance training (ET) group (n = 12; three sessions per week of 45-min continuous treadmill running, n = 12) for a 6-weeks intervention. Baseline and post-intervention assessments included the Wingate Anaerobic Test, elimination rate of blood lactate (BLAer), tennis-specific repeated sprint ability (RSA), and the Yo-Yo Intermittent Recovery Test Level 2 (YoYo-IR2). The results showed that SIT group demonstrated significant improvements in peak and average power during the Wingate test (p = 0.07; p

While previous studies have explored a range of factors governing the optimal use of caffeine (CAF) in athletes, limited research has explored how time of day (TOD) affects the ergogenic effects of various CAF dosages on physical performance. This study aimed to increase knowledge about how different recommended CAF doses (3 mg/kg vs. 6 mg/kg) ingested at different TODs affected maximal high-intensity physical performance and the perception of potential side effects in female athletes. In this double-blind, randomized, and counterbalanced study, 15 low CAF consumer athletes (aged 18.3 ± 0.5 y) underwent six trials, including three testing conditions assessed across two TODs: one in the morning (08:00 a.m.) and one in the evening (06:00 p.m.). During each condition, the participants ingested either a placebo, 3 mg/kg CAF (CAF (3 mg)), or 6 mg/kg CAF (CAF (6 mg)) capsules 60 min before each test with an in-between washout period of at least 72 h. In each trial, the participants performed a countermovement jumps test (CMJ), a modified agility t test (MATT), a repeated sprint ability (RSA), a rating of perceived exertion (RPE), and finally, a CAF side effects questionnaire. Our findings indicate the absence of an ergogenic effect on CMJ, MAT, and RSA performance in the evening after administering CAF (3 mg) or CAF (6 mg) compared to a placebo. Likewise, when CAF was ingested in the morning, there was an improvement in these performances with both CAF (3 mg) and CAF (6 mg), with greater improvement observed after CAF (6 mg). Additionally, neither the CAF dosage nor the TOD had a significant effect on the RPE. The occurrence of side effects increased significantly after the evening ingestion of CAF, particularly with a moderate dose of CAF (6 mg). Our findings indicate that the effectiveness of CAF depends on the TOD and CAF dosage. When ingested in the morning, a moderate dose of CAF (6 mg), rather than CAF (3 mg), is more effective in improving short-term physical performance without affecting CAF side effects in female athletes. Nevertheless, when ingested in the evening, neither dose was sufficient to enhance short-term physical performance, and both dosages increased the incidence of CAF side effects, particularly at a moderate dose. [ABSTRACT FROM AUTHOR]

This study sought to evaluate the effects of oral contraceptive (OC) and hormonal intrauterine device (H-IUD) use, compared with a eumenorrheic (EUM) cycle, on fatigability and recovery between hormone the phases. Peak power (PP), average power (AP), fatigue index (FI), blood lactate, vessel diameter, and blood flow (BF) were measured from a repeated sprint cycle test (10 × 6 seconds) in 60, healthy, active women (mean ± SD; age: 26.5 ± 7.0 years, BMI: 22.5 ± 3.7 kg-m-2) who used monophasic OC (≥6 months; n = 21), had a H-IUD (≥6 months; n = 20), or had regular naturally occurring menstrual cycle (≥3 months) or had a nonhormonal IUD (EUM; n = 19). Subjects were randomly assigned to begin in either the low-hormone phase (LHP) or high-hormone phase (HHP) and were tested once in each phase. Separate univariate analyses of covariances assessed the change from HHP to LHP between the groups, covaried for progesterone, with significance set at p≤ 0.05. All groups demonstrated similar changes in PP, AP, FI, blood lactate, vessel diameter, and BF between the phases (p > 0.05). Although not significant, AP was higher in LHP for OC (A-248.2 ± 1,301.4 W) and EUM (A-19.5 ± 977.7 W) and higher in HHP for H-IUD (A 369.3 ± 1,123.0 W). Oral contraceptive group exhibited a higher FI (A 2.0%) and reduced blood lactate clearance (A 2.5%) in HHP. In recreationally active women, hormonal contraception and hormone phases may minimally impact fatigue and recovery. Individual elite female athletes may benefit from understanding hormonal contraception type as performance and recovery may slightly vary across the cycle. [ABSTRACT FROM AUTHOR]

This study aimed to compare the effects of two elastic band 10-week training programmes on the athletic performance in adolescent female handball players. Participants aged 16.0 ± 0.5 years were randomly assigned to control (CNT, n = 12), standard elastic band (SEB, n = 12), or contrast elastic band (CEB, n = 12) programmes, each performed twice a week supplementing the regular training. The sprint (10 m and 20 m), modified Illinois change-of-direction test (COD), squat jump (SJ), countermovement jump (CMJ), standing long jump (SLJ), back extensor strength (BES), medicine ball throw (MBT), 1-RM bench press, 1-RM half squat, repeated sprint ability, and force-velocity (F-V) tests were measured before and after the intervention. Both CEB and SEB similarly improved sprint (p < 0.01 and p < 0.01) and COD (p < 0.001 and p < 0.01) when compared to CNT. Jumping performance improved significantly (SJ p < 0.01; CMJ p < 0.05) only in CEB, compared to CNT. Strength improved in both experimental groups (p < 0.01; ES: 0.73 < d < 1.59) compared to CNT, and there was a greater increase for CEB than SEB (p < 0.05) in the medicine ball throw (Table 3). Both CEB and SEB increased all RSA scores compared to CNT (p < 0.01; ES: 0.10 < d < 1.22), without significant difference between them. All F-V scores increased significantly in CEB and SEB compared to CNT (p < 0.01; ES: 0.45 < d < 2.47). In addition, CEB showed substantial gains in performance for PPabs, PPrel, and F0 (p < 0.001, p < 0.001 and p < 0.05, respectively) compared to SEB. Ten-week elastic band training conducted within the competitive season improved limb strength, power and F-V profile in female handball players, with a superior effect of the contrast elastic band training mode for upper-limb strength and F-V characteristics. [ABSTRACT FROM AUTHOR]

This study's objective was to investigate the impact of a 10-week in season contrast rubber band training program on athletic performance in young female handball players. Youth athletes (15.8 ± 0.2 years) were randomly assigned to an intervention (n = 16) or a control group (n = 14). The intervention group performed contrast rubber band training (20 sessions over two weeks), while the control group maintained regular in-season training. The modified T-test, squat jump, countermovement jump, standing long jump, repeated sprint ability, 1-RM bench press and half squat, along with upper and lower limb force-velocity tests were performed. The intervention group experienced significantly larger performance enhancements than the control group in the modified T-test [p < 0.001; d = 1.45 %Δ (intervention = −7.1, control = −0.8)], vertical jump [p ≤ 0.009; d ≥ 0.72; %Δ (8.4 < intervention < 19.8, 4.1 < control < 12.2)], 1-RM strength [p ≤ 0.04, d ≥ 0.80; %Δ (37.1 < intervention < 39.7, 7.2 < control < 11.2)], all force-velocity scores for the upper limbs [p ≤ 0.009; d ≥ 0.72; %Δ (21 < intervention < 82, 0.1 < control < 11.6)], three of four force-velocity scores for the lower limb performance [p ≤ 0.02; d ≥ 0.64; %Δ (6.4 < intervention < 31.3, 0.8 < control < 11.1)] and all repeated sprint times [p < 0.001; d ≥ 1.15; %Δ (−3.4 < intervention < −3.1, −1.9 < control < −0.5)]. It was concluded that ten weeks of contrast rubber band training positively affected most motor abilities in youth female handball athletes. Therefore, coaches and practitioners should consider utilizing contrast rubber band strength training as a time and resource-efficient means of improving physical fitness of youth handball players. [ABSTRACT FROM AUTHOR]

This study aimed to compare the effects of two elastic band 10-week training programmes on the athletic performance in adolescent female handball players. Participants aged 16.0±0.5 years were randomly assigned to control (CNT, n = 12), standard elastic band (SEB, n = 12), or contrast elastic band (CEB, n = 12) programmes, each performed twice a week supplementing the regular training. The sprint (10 m and 20 m), modified Illinois change-of direction test (COD), squat jump (SJ), countermovement jump (CMJ), standing long jump (SLJ), back extensor strength (BES), medicine ball throw (MBT), 1-RM bench press, 1-RM half squat, repeated sprint ability, and force-velocity (F-V) tests were measured before and after the intervention. Both CEB and SEB similarly improved sprint (p < 0.01 and p < 0.01) and COD (p < 0.001 and p < 0.01) when compared to CNT. Jumping performance improved significantly (SJ p < 0.01; CMJ p < 0.05) only in CEB, compared to CNT. Strength improved in both experimental groups (p < 0.01; ES: 0.73 < d < 1.59) compared to CNT, and there was a greater increase for CEB than SEB (p < 0.05) in the medicine ball throw (Table 3). Both CEB and SEB increased all RSA scores compared to CNT (p < 0.01; ES: 0.10 < d < 1.22), without significant difference between them. All F-V scores increased significantly in CEB and SEB compared to CNT (p < 0.01; ES: 0.45 < d < 2.47). In addition, CEB showed substantial gains in performance for PP abs , PP rel , and F0 (p < 0.001, p < 0.001 and p < 0.05, respectively) compared to SEB. Ten-week elastic band training conducted within the competitive season improved limb strength, power and F-V profile in female handball players, with a superior effect of the contrast elastic band training mode for upper-limb strength and F-V characteristics.

Background: Hamstring muscles are most affected by multiple sprint-based sports as a result of muscle strain during sprinting, leading to reduced performance and increased risk of injury. Therefore, the purpose of the study was to assess inter-individual variability in hamstrings recovery after a sportspecific repeated-sprint training (RST), through sprint-specific markers of muscle recovery and associated muscle damage biomarkers in women and men. Methods: Healthy females (n = 14) and males (n = 15) underwent 10 repeated 40-m sprints with a 3-min rest pause between each repetition. Force-generating capacity (FGC) by the 90° hip:20° knee test and range of motion Jurdan test, together with serum biomarkers [sarcomeric mitochondrial creatine kinase (sMtCK), oxidative stress, irisin] were tested at baseline and 24-, 48- and 72-h postexercise through a repeated measures design. Participants were classified according to FGC loss into high responders (HR) and low responders (LR). Results: 21 individuals (10 females, 11 males) were classified as HR (FGC loss >20% and recovery >48 h), while 8 individuals (4 females, 4 males) were classified as LR. HR individuals showed unrecovered maximal voluntary isometric contraction (MVIC) torque until 72 h post-training (p = 0.003, np 2 = 0.170), whereas only HR males showed decreased range of motion (p = 0.026, np 2 = 0.116). HR individuals also showed increased sMtCK (p = 0.016, np 2 = 0.128), oxidative stress (p = 0.038, np 2 = 0.106) and irisin (p = 0.019, np 2 = 0.123). Conclusion: There is inter-individual variability in the muscular response to a sport-specific RST, identifiable by MVIC torque assessment. The findings support that the 90° hip:20° knee test is a powerful indirect test to screen hamstrings recovery in both women and men, in a cost-effective way. However, the Jurdan test might not be able to monitor hamstrings recovery in sportswomen after RST. Decreases in muscle capacity are linked to damage to muscle sarcolemma and mitochondria until 72 h post-exercise. Overall, 72 h will not be adequate time to restore hamstrings structure and function after a sport-specific RST in both female and male responders. [ABSTRACT FROM AUTHOR]

Limited research exists concerning how Repeated-Sprint Ability (RSA) performance is impaired and recovered after match-induced loads. The aim of the current study was to describe the effect of post-match acute and residual fatigue on RSA in male semi-professional soccer players. The day before a friendly match, players performed the 7 × 34.2 m Bangsbo RSA Test, which was repeated immediately post-, at 24 hours (h) and 48 h post-match. Internal and external match loads were also monitored during the match. Post-match acute fatigue was reflected in significant impairments in the worst sprint time, the best sprint time, and the mean of the sprint times, but not in fatigue indexes (p < 0.05). Small and non-significant impairments in RSA-derived indices were evident at 24 h post-match (p < 0.05), indicating that a 24 h period was sufficient to recover from post-match residual fatigue. Moreover, RSA performance at post-match and during recovery may be specifically affected by decelerations (p < 0.05). In summary, this study indicates that acute match-induced fatigue may be reflected in marked impairment in RSA performance immediately post-match, while residual match-induced fatigue does not impair RSA performance during the recovery period. [ABSTRACT FROM AUTHOR]

Copyright of Revue Académique des Études Sociales et Humaines is the property of Hassif Benbouali University of Chlef and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ischaemic preconditioning (IPC), brief periods of ischaemia immediately followed by reperfusion applied to a vascular bed, has emerged as a method to improve exercise performance. There is, however, a lack of research exploring repeated episodes of IPC on anaerobic performance. The aim of this study was to determine if a 2-week repeated IPC intervention could enhance anaerobic performance in male academy football players. Eight male academy football players completed two, 2-week intervention trials: six IPC episodes (4 × 5 min at 220 mmHg per episode), and six SHAM episodes (4 × 5 min at 20 mmHg per episode). Prior to and following each intervention trial, the participants completed assessments of anaerobic performance (Running Anaerobic Sprint Test [RAST]), and superficial femoral artery endothelial function (flow-mediated dilation [FMD]). IPC significantly enhanced peak and mean power output by 12% (p = 0.026) and 11% (p = 0.019) and significantly improved superficial femoral artery FMD (p = 0.049). The increase in endothelial function suggests that this may be a mechanism contributing to this enhancement of anaerobic performance. The present study supports the use of repeated IPC prior to matches and training sessions to enhance anaerobic performance. [ABSTRACT FROM AUTHOR]

While previous studies have explored a range of factors governing the optimal use of caffeine (CAF) in athletes, limited research has explored how time of day (TOD) affects the ergogenic effects of various CAF dosages on physical performance. This study aimed to increase knowledge about how different recommended CAF doses (3 mg/kg vs. 6 mg/kg) ingested at different TODs affected maximal high-intensity physical performance and the perception of potential side effects in female athletes. In this double-blind, randomized, and counterbalanced study, 15 low CAF consumer athletes (aged 18.3 ± 0.5 y) underwent six trials, including three testing conditions assessed across two TODs: one in the morning (08:00 a.m.) and one in the evening (06:00 p.m.). During each condition, the participants ingested either a placebo, 3 mg/kg CAF (CAF (3 mg)), or 6 mg/kg CAF (CAF (6 mg)) capsules 60 min before each test with an in-between washout period of at least 72 h. In each trial, the participants performed a countermovement jumps test (CMJ), a modified agility t test (MATT), a repeated sprint ability (RSA), a rating of perceived exertion (RPE), and finally, a CAF side effects questionnaire. Our findings indicate the absence of an ergogenic effect on CMJ, MAT, and RSA performance in the evening after administering CAF (3 mg) or CAF (6 mg) compared to a placebo. Likewise, when CAF was ingested in the morning, there was an improvement in these performances with both CAF (3 mg) and CAF (6 mg), with greater improvement observed after CAF (6 mg). Additionally, neither the CAF dosage nor the TOD had a significant effect on the RPE. The occurrence of side effects increased significantly after the evening ingestion of CAF, particularly with a moderate dose of CAF (6 mg). Our findings indicate that the effectiveness of CAF depends on the TOD and CAF dosage. When ingested in the morning, a moderate dose of CAF (6 mg), rather than CAF (3 mg), is more effective in improving short-term physical performance without affecting CAF side effects in female athletes. Nevertheless, when ingested in the evening, neither dose was sufficient to enhance short-term physical performance, and both dosages increased the incidence of CAF side effects, particularly at a moderate dose.

Background: Hamstring muscles are most affected by multiple sprint-based sports as a result of muscle strain during sprinting, leading to reduced performance and increased risk of injury. Therefore, the purpose of the study was to assess inter-individual variability in hamstrings recovery after a sport-specific repeated-sprint training (RST), through sprint-specific markers of muscle recovery and associated muscle damage biomarkers in women and men.Methods: Healthy females (n = 14) and males (n = 15) underwent 10 repeated 40-m sprints with a 3-min rest pause between each repetition. Force-generating capacity (FGC) by the 90°hip:20°kneetest and range of motion Jurdan test, together with serum biomarkers [sarcomeric mitochondrial creatine kinase (sMtCK), oxidative stress, irisin] were tested at baseline and 24-, 48- and 72-h post-exercise through a repeated measures design. Participants were classified according to FGC loss into high responders (HR) and low responders (LR).Results: 21 individuals (10 females, 11 males) were classified as HR (FGC loss >20% and recovery >48 h), while 8 individuals (4 females, 4 males) were classified as LR. HR individuals showed unrecovered maximal voluntary isometric contraction (MVIC) torque until 72 h post-training (p = 0.003, np2 = 0.170), whereas only HR males showed decreased range of motion (p = 0.026, np2 = 0.116). HR individuals also showed increased sMtCK (p = 0.016, np2 = 0.128), oxidative stress (p = 0.038, np2 = 0.106) and irisin (p = 0.019, np2 = 0.123).Conclusion: There is inter-individual variability in the muscular response to a sport-specific RST, identifiable by MVIC torque assessment. The findings support that the 90°hip:20°kneetest is a powerful indirect test to screen hamstrings recovery in both women and men, in a cost-effective way. However, the Jurdan test might not be able to monitor hamstrings recovery in sportswomen after RST. Decreases in muscle capacity are linked to damage to muscle sarcolemma and mitochondria until 72 h post-exercise. Overall, 72 h will not be adequate time to restore hamstrings structure and function after a sport-specific RST in both female and male responders.

Objective This study examined the effects of oral and topical (PR Lotion; Momentous) sodium bicarbonate (NaHCO3) during a battery of team sport-specific exercise tests. Method In a block randomized, crossover, double-blind, placebo-controlled design, 14 recreationally trained male team sport athletes performed a familiarization visit and three experimental trials receiving: (i) 0.3 g·kg−1 body mass (BM) NaHCO3 in capsules + placebo lotion (SB-ORAL), (ii) placebo capsules +0.9036 g·kg−1 BM PR Lotion (SB-LOTION), or (iii) placebo capsules + placebo lotion (PLA). Supplements were given ~120 min prior to the team sport-specific exercise tests: countermovement jumps (CMJ), 8 × 25 m repeated sprints and Yo-Yo Intermittent Recovery Level 2 (Yo-Yo IR2). Blood acid–base balance (pH, bicarbonate) and electrolytes (sodium, potassium) were measured throughout. Rating of perceived exertion (RPE) was recorded after each sprint and post-Yo-Yo IR2. Results Distance covered during the Yo-Yo IR2 was 21% greater for SB-ORAL compared with PLA (+94 m; p = 0.009, d = 0.64) whereas performance was only 7% greater for SB-LOTION compared with PLA (480 ± 122 vs. 449 ± 110 m; p = 0.084). Total completion time for the 8 × 25 m repeated sprint test was 1.9% faster for SB-ORAL compared with PLA (−0.61 s; p = 0.020, d = 0.38) and 2.0% faster for SB-LOTION compared with PLA (−0.64 s; p = 0.036, d = 0.34). CMJ performance was similar between treatments (p > 0.05). Blood acid–base balance and electrolytes were significantly improved for SB-ORAL compared with PLA, but no differences were observed for SB-LOTION. Compared to PLA, RPE was lower for SB-LOTION after the fifth (p = 0.036), sixth (p = 0.012), and eighth (p = 0.040) sprints and for SB-ORAL after the sixth (p = 0.039) sprint. Conclusions Oral NaHCO3 improved 8 × 25 m repeated sprint (~2%) and Yo-Yo IR2 performance (21%). Similar improvements in repeated sprint times were observed for topical NaHCO3 (~2%), but no significant benefits were reported for Yo-Yo IR2 distance or blood acid–base balance compared to PLA. These findings suggest that PR Lotion might not be an effective delivery system for transporting NaHCO3 molecules across the skin and into systematic circulation, therefore further research is needed to elucidate the physiological mechanisms responsible for the ergogenic effects of PR Lotion.

Introduction. The ability to perform repeated sprints is one of the most important physical abilities in soccer. Aim of Study. The aim of this study was to examine the relationship between the ability to perform repeated sprints (6 × 20 m in a 15-s cycle) in female soccer players from two different age groups, with aerobic capacity (YYIR1), jumping ability (single-leg hop test), isokinetic strength (60°/s, 180°/s, 300°/s), speed performance (S10-m and S30-m), and change of direction ability (505 COD test). The second objective of the study was to compare the performances of the two different groups in the tests. Material and Methods. Twenty-four female soccer players from Greece participated in this study and they were divided into two groups: (i) U-16 (division II) female soccer athletes (age: 15.8 ± 0.8 years, height: 160.5 ± 5.1 cm, body mass: 59.4 ± 7 kg), and (ii) adult female (division I) soccer athletes (age: 21.9 ± 4.1 years, height: 165.7 ± 6.1 cm, body mass: 62.2 ± 7.5 kg). The Pearson correlation coefficient and t-test for independent samples were used for statistical analysis. Results. The S10-m, S30-m and single-leg hop tests appeared to be the variables most associated with the total time in the RSA test in U-16 female soccer players. S10-m and the change of direction ability appeared to be the variables most associated with the total time in the RSA test in adult female players. Conclusions. It seems that U-16 Greek female soccer players do not differ from adults in most of the physical fitness tests conducted in the field and laboratory. [ABSTRACT FROM AUTHOR]

Small-sided games (SSGs) serve as a valuable tool for aerobic training for both professional and amateur teams. Nevertheless, some studies suggest that, under specific conditions, small SSGs may not replicate the highintensity efforts (20-25 km/h) and repeat sprints (>25 km/h) demanded by full games when compared with larger small-side game formats or match play. Conversely, high-intensity interval training (HIIT) has been shown to enhance maximal oxygen uptake, the lactic threshold, intermittent high-intensity effort capabilities, and rapid recovery between intense efforts. This study aimed to evaluate the effects of SSGs in comparison to HIIT on maximal oxygen uptake (VO2MAX), repeat sprint ability (RSA), and agility in youth soccer players. A randomized parallel-group study involving 12 players per group was conducted. The experimental group underwent a nine-week SSGs-based intervention, ranging from two vs. two to six vs. six formats, with a training duration between 20 and 40 min, while the control group engaged in HIIT for the same duration and frequency. The testing battery (baseline and postintervention) occurred over three different days with assessments at 8:00 a.m., both at the club's training ground (Course Navette, Sprint Repeated Test, and Illinois Test) and in the laboratory (ergospirometry) with an environmental temperature of 24°C and relative humidity of 60%. The study commenced in the middle of the competitive season. Statistical analyses revealed no significant differences in maximal oxygen uptake between the SSGs-based training group and the control group (p = 0.44). However, the experimental group exhibited a 6% improvement in performance, while the control group showed a 12% improvement, with a moderate effect size (ES = 0.4). Additionally, the experimental group demonstrated statistically significant improvements in all RSA variables: best time (p = 0.02; 95% confidence interval (CI95%): -0.18; -0.01; ES = 1.1), average time in all sprints (p = 0.005; CI95%: -0.33; -0.06; ES = 1.4), total time in all sprints (p = 0.003; CI95%: -2.17; -0.52; ES = 1.4), and the percentage of decrease tended towards significance (p = 0.07; CI95%: -3.07; 0.15; ES = 0.8) compared with the control group. Agility showed no significant differences between the two groups (p = 0.45). Overall, no statistically significant differences were found in maximal oxygen uptake and agility between youth soccer players practicing SSGs and those engaged in HIIT after nine weeks. Notably, a significant enhancement in repeat sprint ability was observed in the SSGs group compared to the HIIT group. Consequently, during the in-season, amateur team coaches should favor SSGs training instead of interval exercises to optimize training. [ABSTRACT FROM AUTHOR]

Team sport athletes commonly perform repeated short-duration sprints (≤10 seconds) separated by brief recovery periods (≤60 seconds). The ability to maintain performance over a series of sprints is termed repeatedsprint ability (RSA). The physiological limiters of RSA include decreased force production capacity, insufficient energy supply, and metabolite accumulation. These limiting factors can be improved through repeated-sprint training, with greater RSA gains when performing this training with systemic hypoxia (i.e., reduced fraction of inspired oxygen). Exercising with blood flow restriction (BFR) causes localized hypoxia and a substantial metabolite load, which may provide an adjunct training method to improve RSA. Training with BFR augments muscular strength and adenosine triphosphate supply, which may improve subsequent sprint performance. Improved aerobic fitness, phosphocreatine resynthesis, and metabolite removal from BFR training could also enhance between-sprint recovery to resist fatigue. Despite the possible physiological benefits of repeated-sprint BFR training to improve RSA, there are no published reviews to collate this information. Therefore, this review proposes a theoretical framework for how BFR training could combat fatiguing factors and improve RSA based on current knowledge of the physiological impact of repeated-sprint training and BFR. Finally, guidance will be provided regarding how practitioners may implement BFR training to improve RSA. [ABSTRACT FROM AUTHOR]

The study investigated the impact of maximal aerobic speed (MAS) and maximal anaerobic sprint (MANS) on repeated sprint ability (RSA) in soccer. Methods: 17 amateur-to semi-professional soccer players, age 19 (± 4) years, were tested for maximal oxygen consumption (VO2max), oxygen cost of running (Cr), RSA consisting of 15-20m sprint each divided by a 100 seconds dribble track, and 40-meter sprint performance. MAS was calculated as VO2max - Cr -1, and MANS was defined as the highest velocity in the 40-meter sprint. Results: There was a strong correlation between MAS and average 20-meter RSA velocity (r = 0.760; p < 0.01), and between MAS and performance decrement (r = -0.648; p < 0.01). The product of 0.5MAS + 0.5MANS exhibited the strongest correlation with RSA (r = 0.813; p < 0.01). Conclusion: The combination of MAS and MANS strongly predicted RSA. High-intensity aerobic interval training (HIIT) and maximal strength training (MST) are recommended to improve MAS and MANS, and could thus lead to better RSA on the soccer field. [ABSTRACT FROM AUTHOR]

Understanding the physical fitness elements that influence high-intensity running ability during rugby matches is crucial for optimizing player performance and developing effective training strategies. In this study, we aimed to investigate the relationships between various physical fitness components and high-intensity running ability in rugby. For this purpose, 60 Japanese university rugby players were randomized into four groups and two matches were played. The participants were monitored in two matches, and their running abilities were assessed using GPS sensors. The running time was divided into three running velocity categories: distance run at ≤5.4 km/h (low-intensity running); distance run at 5.5~17.9 km/h (medium-intensity running), and distance run at ≥18.0 km/h ≤(high-intensity running) and backs and forwards were evaluated separately. To determine which physical fitness test is more predictive of performance, we decided to correlate several physical test performances with the running time intensities during the matches. Independently of the position, the high-intensity running time correlated with the repeated sprint ability (RSA) and the 40 m sprint speed. The results suggest that RSA measured in the field is the most important high-intensity running ability predictor during a match for both positions. [ABSTRACT FROM AUTHOR]

High-intensity interval training (HIIT) is widely used in soccer. The purpose of the study was to investigate the effect of an HIIT program on the performance of soccer players under the age of 17. Twenty-nine youth players participated in this study. Players were randomly separated into two groups: control group (n = 14) and intervention group which performed extra HIIT (EX, n = 15). The duration of the training program was 4 weeks. Sprint 10 m, 30 m, countermovement jump (CMJ), squat jump (SJ), Illinois agility test, YO-YO intermitted recovery test 1, and repeated sprint ability (RSA) test (RSAbest, RSAmean, RSAdecrement) were measured pre and post the training program. The performance in 10 m, Illinois test, and RSAmean improved in the EX group (P = 0.022, P = 0.047, and P = 0.045, respectively). The performances of the two groups differed significantly in post-measurement of 10 m, Illinois test, and RSAmean (P = 0.046, P = 0.039, and P = 0.044, respectively). This study supports that a short-term program of HIIT can improve acceleration, agility, and RSA performance. [ABSTRACT FROM AUTHOR]

An editorial focuses on optimizing athletic training through the analysis of neuromuscular variables across various sports disciplines. It examines recovery protocols, marathon performance prediction, the acute effects of different CrossFit modalities, and the impact of blood flow restriction training (BFRT) on muscle activation and strength.

This study aimed at investigating the efficacy of a 6-week combined plyometric and speed training program focusing on developing the speed-strength abilities of U14 soccer players. The study was conducted under the conditions of a two-group parallel experiment. Experimental groups I. and II. (EG I. and II.) consisted of youth soccer players (n = 20 and 18) in the top German and Slovak leagues, respectively. To obtain data, we performed 6 tests: squat jump (SJ), countermovement jump (CMJ), drop jump (DJ), 10-m sprint test, 20-m sprint test, and 505 agility test. EG I. players completed a 6-week experimental period, including two training sessions per week using plyometrics and short sprints, while EG II. players underwent the same experimental period without plyometrics and short sprints. Both groups completed an identical training program to develop their speed skills. Compared to the results of the EG II. group, the values of all tests were significantly more increased in the EG I. group: the SJ (p < 0.00001), CMJ (p < 0.00001), DJ (p < 0.00001), 10-m sprint test (p = 0.00122), 20-m sprint test (p = 0.00027), and 505 agility test (p = 0.00062). The results of the combined plyometric and speed program demonstrated higher efficacy in developing selected speed and strength parameters compared to the speed program without strength training. In summary, our study showed the necessity of using plyometric and sprint drills alongside game-specific training in soccer. [ABSTRACT FROM AUTHOR]

Purpose: The purposes of the study were to: i) verify the variations in training load and the subsequent effects on swimming performance parameters, biochemical parameters, and autonomic nervous activity during a water polo season; ii) investigate the sensitivity of physiological markers in tracking training load and performance variations, and iii) verify the overreaching prevalence. Method: The training load of 20 female water polo players was monitored (using the session rating of perceived exertion method [sRPE], training monotony, and strain), and the lactate minimum speed (LMS), repeated sprint ability (RSA), plasma hormone and glutamine concentration, salivary immunoglobulin A (SIgA), and heart rate variability (lnRMSSD) were evaluated during the season. Result: The training load parameters were higher in the competitive cycle (p ≤ 0.002). The LMS improved only in the general cycle from baseline (p =.015), while the RSA best time improved in the general (p =.002) and specific cycles (p =.012) from baseline and deteriorated in the competitive from general cycle (p =.008). The SIgA secretion rate presented a reduction only in the specific cycle from baseline (p =.032), while the lnRMSSD increased in the general (p =.038) and competitive (p <.001) cycles from baseline. Five athletes were diagnosed as overreaching state. Conclusion: Therefore, the physiological markers (i.e., plasma hormone and glutamine concentration, SIgA, and lnRMSSD) showed little sensitivity to detect changes in training load and swimming performance. The higher training loads applied in the competitive cycle seem to limit swimming performance gains. [ABSTRACT FROM AUTHOR]

We examined physiological responses and fatigue in adolescent boys and girls during a repeated shuttle-sprint running test in a school setting. We also compared three calculation methods to assess fatigue during repeated sprints: the fatigue index (FI), the percent sprint decrement (Sdec), and the slope of performance decrement (SlopeD). Twenty-six adolescent students (10 girls and 16 boys, age: 15.3 ± 0.5 y) performed six 30 m sprints with a 180° change of direction at 15 m, interspersed with 10 s of recovery. Blood lactate (BL), heart rate (HR) and countermovement jump performance (CMJ) were measured before and after the sprint test. Boys achieved significantly faster sprint times (11.7% to 14.8% faster than girls in all sprints, p < 0.01), and had higher post-test BL compared with girls (14.0 ± 2.9 vs. 11.3 ± 3.2 mmol/L; p = 0.02; d = 0.93). However, all fatigue indices (FI, Sdec and SlopeD) were similar in boys and girls (FI = 11.5 ± 5.0 vs. 11.5 ± 5.0; SlopeD = 10.6 ± 4.8 vs. 14.5 ± 5.1; Sdec = 5.6 ± 2.2 vs. 7.3 ± 2.2, in boys and girls, respectively, p > 0.05 for all) and were highly correlated with each other (r = 0.86 to 0.97, p < 0.01). CMJ was higher in boys (p < 0.05), but CMJ performance dropped similarly from pre- to post-test in boys and girls (13.7 ± 7.0%, p < 0.01). In conclusion, neuromuscular fatigue during and after repeated shuttle-sprint running is similar in boys and girls, despite the faster sprint times, higher CMJ and higher BL in boys. SlopeD may be used as an alternative index to quantify fatigue during repeated shuttle-sprinting, as it takes into account performance in all sprints and may provide an average sprint-by-sprint performance drop. [ABSTRACT FROM AUTHOR]

This study examined the effects of 8-week combined plyometric exercise and high intensity running training (combined training) on the performance fitness in male U17 handball players. Participants were randomly divided between experimental (E; n = 15; age: 16.5 ± 0.4 years) and control (C; n = 13; age: 16.7 ± 0.3 years) groups. The E group performed combined training (4 workshops) twice a week over 8 weeks. Each session lasted approximately 35 min. The C maintained regular in-season training. Before and after the combined training, both groups underwent repeated sprint ability (RSA), sprint performance (5m, 10m, 20m and 30m), change of direction test (Modified change-of-direction T-test (T-half)), vertical jump (squat jump (SJ), counter-movement jump (CMJ), counter-movement jump with aimed arms (CMJA)), horizontal jump (five-jump test (5JT)), strength (1-RM half squat), and 20-meter shuttle run. Group x time interaction showed significant increases on sprint performance (p < 0.01, 8.6%; p < 0.001, 7.3%; p < 0.05, 6.9%; and p < 0.01, 8.9% over distances of 5m, 10m, 20m and 30m respectively) in E relative to C. The T-half also showed significant gains for E (p < 0.05, 6.8%), as did vertical jumping (p < 0.01, 32.7%; p < 0.001, 32.6% and p < 0.001, 23% for SJ, CMJ and CMJA respectively) and horizontal jumping (p < 0.05, 13.3%) compared to C. Moreover, there were significant improvements of RSA and 20 m shuttle run in E compared to C. However, there were no significant differences in 1-RM half squat between groups. We conclude that the allocation of short periods of a combined training is effective in enhancing performance fitness and thus can be commended to male U17 Handball participants as a potentially useful component of their training. [ABSTRACT FROM AUTHOR]

Warm-up routines include various tasks focused on the peripheral contractile properties and nervous motor command. This present study was aimed at investigating the acute effects of different warm-up routines, emphasizing either peripheral (post-activation performance enhancement, PAPE) or central (motor imagery, MI) contributions on sport-specific tasks. Eleven young female athletes took part in this cross-over, randomized, controlled trial. They underwent three experimental sessions composed of a standardized warm-up followed by 10 min of (1) rest (CONTROL), (2) maximal concentric leg press (PAPE), or (3) mental repetitions of sprint tasks (MI). Post-tests consisted of reaction time, arrowhead agility test, 20 m sprint, repeated sprint ability, and NASA-TLX fatigue questionnaire. PAPE and MI significantly enhanced the arrowhead agility test (p < 0.001 and p = 0.012, respectively) and repeated sprint ability (p = 0.002 and p = 0.035, respectively) compared to CONTROL, without any difference between PAPE and MI. The 20 m sprint time was better after PAPE as compared to MI (p = 0.005) and CONTROL (p < 0.001), without any difference between MI and CONTROL. Reaction time and the NASA-TLX questionnaire were not affected by the warm-up modalities (p > 0.05). PAPE was the most efficient to optimize warm-up due to its greater peripheral contribution that would improve muscle contractility. MI specifically improved the imagined tasks mostly by central contribution. [ABSTRACT FROM AUTHOR]

PURPOSE This study aimed to investigate the correlation between repeated sprint ability (RSA) and Hoff test performance in high school soccer players. METHODS Fourteen male high school football players participated in this study. After measuring body composition, the Bangsbo Sprint Test for RSA and Hoff test were performed. The tests were conducted in the field to create an experimental environment similar to that during actual training and competition. RESULTS A significant correlation was observed between the fatigue index (FI) in the RSA and running distance in the Hoff test (p

Background and Study Aim. The aim of the research is to evaluate the 7x34.2 m Repeated Straight Sprint Test (RSST) and 7x34.2 m Repeated Change of Direction Sprint Test (RCST), which are used for improvement, measurement, and evaluation of repeated sprint ability, by using Global Positioning System (GPS). Material and Methods. Twenty-two professional soccer players participated in the research voluntarily. Internal and external load data were examined comparatively by using data as before and after the repeated sprint tests. External load data measured by 10 Hz GPS. Results. When the findings of the research are examined, it is seen that values of blood lactate concentrations which are taken after three and five minutes of the RCST are significantly higher than RSST protocol (p < 0.001***, p = 0.042*, respectively). In the study, the value of lactate which is taken five minutes after the RSST was measured as 9.60 ± 2.65 mM, while the value which is taken three minutes after RCST was measured as 9.75 ± 2.51 mM. Nevertheless, whereas there was a difference between the two tests in terms of lactate values, no significant difference was found in terms of perceived exertion. Conclusions. As a conclusion, according to the analyzes made after the RCST and RSST, we can say that the internal and external load performances of the athletes were very different. It has been observed that coaches, athletes, and practitioners can use two different test protocols for different objectives according to the purposes they set.

The purpose of this systematic review was to overview the physiological and performance effects of high-intensity interval training (HIIT) in tennis players. Searches for this review were performed by using four electronic databases: Web of Science, Scopus, SPORTDiscus with Full-Text, and PubMed. Intervention studies investigating the effects of HIIT on tennis players were searched from inception to December 29th, 2021. Seven studies met all inclusion criteria and were included in the study. The findings revealed that tennis players who participated in HIIT interventions had improved their aerobic capacity and tennis performance. Fluctuating results were reported for agility, sprint, and jump performances. In conclusion, the results of the review may suggest that HIIT is beneficial for tennis players to achieve improvement in cardiorespiratory fitness and technical abilities regardless of age, gender, and competitive level. [ABSTRACT FROM AUTHOR]

Dietary nitrates have hemodynamic and metabolic effects on the body. This study aimed to investigate nitrate intake's effect on quadricep muscle oxygen saturation (StO2) of semi-professional soccer players during a repeated speed test (RSA). In a randomized, crossover design, 10 semi-professional soccer men players (21.3 ±0.9yrs) performed two conditions: In one they consumed a nitrate-rich concentrated beetroot juice (250 mL/150 mg of NO3-) and in the other a placebo, 2h before a repeated sprint test. StO2 of the right vastus lateralis muscle was measured by near-infrared spectroscopy. A paired samples t-test was used to compute any differences in the subjects' performance on the StO2 and on RSA test. The level of significance was set at p < 0.05. The supplementation of nitrates limited the decrease in muscle oxygenation during the six sprints of RSA test (p < 0.001) and also, there seemed to be a tendency for limited the decrement of performance on RSA test (t = -1.586, p = 0 .157, η² = 0 .218). In conclusion, acute nitrate supplementation reduces the decrement of muscle oxygenation during exercise with repeated sprints and leads to a tendency of fatigue resistance during repeated sprints under controlled situations. Nitrate supplementation may have an ergogenic effect during exercise with repeated sprints via the higher muscle oxygenation. [ABSTRACT FROM AUTHOR]

This case study reports the effects of six sessions of repeated sprint training in hypoxia (RSH) over 3 weeks on explosive power production capacity and repeated sprint ability (RSA) in two Japanese international‐level foil fencers. The six RSH sessions (60‐s sprints in total per session: consisting of two sets of five 6‐s sprints with 30‐s passive recovery, at simulated altitude of 3000 m) caused improvements of peak power output (PPO; Athlete A: 5.1%; Athlete B: 3.2%) and mean power output (MPO; Athlete A: 4.4%; Athlete B: 1.6%) over the 10 repeated sprints, respectively. The observed findings suggest that as few as six RSH sessions over 3 weeks can improve, at least to some extent, explosive power production capacity (PPO) and RSA (MPO) in the two elite fencers. To the best of our knowledge, this is the first study to apply short‐term RSH in combat sport (fencing) with international‐level athletes. Further studies are required to explore the effectiveness of short‐term RSH in combat sports with a more robust study design (e.g., randomized control trial with adequate statistical power) as the modality of RSH would suit physical and physiological demands in the majority of combat sports (e.g., wrestling, boxing). [ABSTRACT FROM AUTHOR]

Purpose: This study investigates the effects of normobaric hypoxia on repeated sprint exercise (RSE) with different balance between oxidative (phosphocreatine and oxidative pathway) and glycolytic contributions. Therefore, performance and psychophysiological responses were compared during RSE to exhaustion with the same exercise-to-rest ratio (1:2) but different sprint durations (5, 10, or 20 s) either in normoxic (RSN) or hypoxic (RSH; F io 2 = 0.13) conditions. Methods: On separate visits, 10 active participants completed in random order three cycling RSN (5:10; 10:20 and 20:40) and three similar RSH sessions to exhaustion. Vastus lateralis muscle oxygenation was recorded by near-infrared spectroscopy. Blood lactate concentration, limb and breathing discomfort, and ratings of perceived exertion were measured. Results: Total sprint number was smaller in hypoxia than in normoxia for 5:10 (20.8 ± 8.6 vs 14.7 ± 3.4; P = 0.014) and 10:20 (13.7 ± 6.3 vs 8.8 ± 2.5; P = 0.018) but not 20:40 (5.6 ± 1.9 vs 5.6 ± 2.5). The fatigue index was larger in hypoxia only for 5:10 (−43.5%, P < 0.001). Irrespective of condition, blood lactate concentration increased with the sprint duration with higher values for 20:40 than 5:10 (13.1 ± 2.7 vs 11.5 ± 2.2 mmoL·L−1; P = 0.027). Limb and breathing discomfort and ratings of perceived exertion did not differ in all RSE. Muscle oxygenation was mainly impacted by sprint duration (i.e., main effect of sprint duration on [HHb] min, [tHb] max, Δ[HHb], and Δ[tHb]) but not by hypoxia. The normoxia-to-hypoxia percentage decrease for total sprint number for 5:10 was correlated with the highest power output over 5 s (R 2 = 0.55; P = 0.013) and 10 s (R 2 = 0.53; P = 0.016). Conclusions: Hypoxia impairs repeated sprint ability when the oxidative but not the glycolytic contribution is substantial. The oxidative–glycolytic balance, influenced partly by sprint duration, is key during repeated sprint in hypoxia. [ABSTRACT FROM AUTHOR]

Abstract This case study reports the effects of six sessions of repeated sprint training in hypoxia (RSH) over 3 weeks on explosive power production capacity and repeated sprint ability (RSA) in two Japanese international‐level foil fencers. The six RSH sessions (60‐s sprints in total per session: consisting of two sets of five 6‐s sprints with 30‐s passive recovery, at simulated altitude of 3000 m) caused improvements of peak power output (PPO; Athlete A: 5.1%; Athlete B: 3.2%) and mean power output (MPO; Athlete A: 4.4%; Athlete B: 1.6%) over the 10 repeated sprints, respectively. The observed findings suggest that as few as six RSH sessions over 3 weeks can improve, at least to some extent, explosive power production capacity (PPO) and RSA (MPO) in the two elite fencers. To the best of our knowledge, this is the first study to apply short‐term RSH in combat sport (fencing) with international‐level athletes. Further studies are required to explore the effectiveness of short‐term RSH in combat sports with a more robust study design (e.g., randomized control trial with adequate statistical power) as the modality of RSH would suit physical and physiological demands in the majority of combat sports (e.g., wrestling, boxing).

Simple Summary: Football is a sport which imposes an intermittent type of physical exertion, and one of the main physical demands of the game is sprinting, covering mostly short distances on repeated occasions. Sprinting imposes maximum demands, especially on the hamstrings muscle group; this activity frequently contributes to the occurrence of injury to the biceps femoris long head muscle, particularly in the later stages of the game, suggesting that fatigue may play an important role. After the injury, sprint performance and strength might be reduced, and muscle morphology can be altered even after the player returns to competition. Therefore, the aim of the study was to verify the effect of a fatiguing task on sprint performance, the biceps femoris long head muscle morphology and the hamstring muscle force capacity. Moreover, a comparison was performed between injured players and healthy controls and injured versus contralateral limbs. Muscle morphology was assessed through ultrasound techniques, while muscle force was estimated using a dynamometry assessment. It was concluded that injured players tend to be faster than the healthy control group and display shorter biceps femoris long head fascicle length when compared with the contralateral limb and healthy controls. The aim of this study was to compare the biceps femoris long head (BFlh) architecture between football players with (twelve) and without (twenty) history of BFlh injury before and after a repeated sprint task. Fascicle length (FL), pennation angle (PA) and muscle thickness (MT) were assessed at rest and in the active condition before and after the repeated sprint protocol. Athletes with previous BFlh injury showed shorter FL at rest (p = 0.014; η2p = 0.196) and active state (p < 0.001; η2p = 0.413), and greater PA at rest (p = 0.002; η2p = 0.307) and active state (p < 0.001; η2p = 0.368) before and after the task. Intra-individual comparisons showed that injured limbs have shorter FL at rest (p = 0.012; η2p = 0.519) and in the active state (p = 0.039; η2p = 0.332), and greater PA in passive (p < 0.001; η2p = 0.732) and active conditions (p = 0.018; η2p = 0.412), when compared with contralateral limbs. Injured players, at rest and in the active condition, display shorter BFlh FL and greater PA than contralateral and healthy controls after repeated sprints. Moreover, the BFlh of injured players presented a different architectural response to the protocol compared with the healthy controls. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the relationships between vertical jumps (VJ) and various on-ice skating performances of junior ice hockey players (n = 19). The three modes of VJ or off-ice measures were countermovement jump with arm swing (CMJ), squat jump (SJ) and depth drop jump (DDJ). The on-ice skating performance was measured by the skating multistage aerobic test (SMAT), forward and backward acceleration test, top speed test, and repeated sprint ability (RSA) test. The relationships between the variables were quantified using Pearson's product-moment correlation. DDJ showed a significant positive correlation with forward average skating speed (FASS) (r = 0.62) and strong correlations with backward average skating speed (BASS) (r = 0.81), and maximum skating speed (MSS) (r = 0.71). SJ was found to be strongly correlated with BASS (r = 0.82) and MSS (r = 0.76), whereas the only on-ice performance that significantly correlated with CMJ was BASS (r = 0.68). All three modes of VJ were inversely and non-significantly correlated with performance decrement index and fatigue index, as determined by the RSA test. SMAT was not significantly correlated with either VJ or RSA. Correlations between all three modes of VJ tests were significant. Therefore, this study concludes that: (1) DDJ can be used as a predictor of all the ice skating speed tests, whereas SJ can predict BASS and MSS. CMJ, on the other hand, can predict the performance of only BASS. (2) RSA performance cannot be predicted from CMJ, SJ, or DDJ tests, and (3) neither any of the VJ nor RSA can predict skating endurance of junior ice hockey players. [ABSTRACT FROM AUTHOR]

In Bicycle Motocross (BMX) performance is determined by the riders' sprint ability and power output. Therefore, descriptive and predictive performance assessments through laboratory and field tests are of interest. Twelve members of the Spanish BMX National Team performed 4 laboratory tests, including 1RM in squat, a Wingate test, a 5x6-s repeated sprint test (RST) and a force-velocity profile test. These tests were compared with the riders' field performance using the best lap of a simulated BMX competition consisting of 6 all-out laps on a standard BMX track. Pearson's correlation and linear regression analysis showed a significant association (p < 0.05) between the riders' field performance and the 1RM (r = 0.84; R2 = 0.65), the peak power output in the RST (r = 0.87; R2 = 0.78) and the peak power, the mean power and the lactate production in the Wingate test (r = 0.68–0.77; R2 = 0.14–0.65), as well as maximal power from the force-velocity profile (r = 0.71; R2 = 0.53). The laboratory tests included in this study can show information about BMX riders' performance, with the highest values for the peak power obtained in the repeated sprint test (78% of the variance in common). [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the relationships between vertical jumps (VJ) and various on-ice skating performances of junior ice hockey players (n = 19). The three modes of VJ or off-ice measures were countermovement jump with arm swing (CMJ), squat jump (SJ) and depth drop jump (DDJ). The on-ice skating performance was measured by the skating multistage aerobic test (SMAT), forward and backward acceleration test, top speed test, and repeated sprint ability (RSA) test. The relationships between the variables were quantified using Pearson’s product-moment correlation. DDJ showed a significant positive correlation with forward average skating speed (FASS) (r = 0.62) and strong correlations with backward average skating speed (BASS) (r = 0.81), and maximum skating speed (MSS) (r = 0.71). SJ was found to be strongly correlated with BASS (r = 0.82) and MSS (r = 0.76), whereas the only on-ice performance that significantly correlated with CMJ was BASS (r = 0.68). All three modes of VJ were inversely and non-significantly correlated with performance decrement index and fatigue index, as determined by the RSA test. SMAT was not significantly correlated with either VJ or RSA. Correlations between all three modes of VJ tests were significant. Therefore, this study concludes that: (1) DDJ can be used as a predictor of all the ice skating speed tests, whereas SJ can predict BASS and MSS. CMJ, on the other hand, can predict the performance of only BASS. (2) RSA performance cannot be predicted from CMJ, SJ, or DDJ tests, and (3) neither any of the VJ nor RSA can predict skating endurance of junior ice hockey players.

Understanding the physical fitness elements that influence high-intensity running ability during rugby matches is crucial for optimizing player performance and developing effective training strategies. In this study, we aimed to investigate the relationships between various physical fitness components and high-intensity running ability in rugby. For this purpose, 60 Japanese university rugby players were randomized into four groups and two matches were played. The participants were monitored in two matches, and their running abilities were assessed using GPS sensors. The running time was divided into three running velocity categories: distance run at ≤5.4 km/h (low-intensity running); distance run at 5.5~17.9 km/h (medium-intensity running), and distance run at ≥18.0 km/h ≤(high-intensity running) and backs and forwards were evaluated separately. To determine which physical fitness test is more predictive of performance, we decided to correlate several physical test performances with the running time intensities during the matches. Independently of the position, the high-intensity running time correlated with the repeated sprint ability (RSA) and the 40 m sprint speed. The results suggest that RSA measured in the field is the most important high-intensity running ability predictor during a match for both positions.

Purpose: This study investigated the effects of 1400 mL intake of alkaline electrolyzed water (AEW) or purified water (PW) into which carbohydrate-electrolyte (CE) was dissolved on improving physiological responses during exercise under heat stress. Methods: This double-blinded, crossover randomized controlled trial included 10 male participants who completed two exercise trials in a hot environment (35 °C, ambient temperature, and 50% relative humidity) after consuming CE-dissolved PW (P-CE) or CE-dissolved AEW (A-CE). The exercise trial consisted of running for 30 min on a treadmill (at an intensity corresponding to 65% of heart rate reserve adjusted for heat stress conditions) and repeated sprint cycling (10 × 7-s maximal sprint cycling), with a 35-min rest interval between the two exercises, followed by a 30-min post-exercise recovery period. Before and after running, and after cycling, the participants drank P-CE (hydrogen concentration of 0 ppm, pH 3.8) or A-CE (0.3 ppm, pH 4.1). Blood samples were obtained before, during (rest interval between running and cycling), and post-exercise. Results: Repeated sprint performance and oxidative stress response did not differ between the P-CE and A-CE trials. A-CE consumption significantly attenuated the increase in blood lactate concentration during the running exercise but not during repeated sprint cycling under heat stress conditions. Conclusion: Our findings suggested that A-CE did not significantly affect repeated sprint performance; however, the attenuated elevation in blood lactate by A-CE ingestion implies a partial enhancement of endurance performance during submaximal exercise under heat stress.

Dietary nitrates have hemodynamic and metabolic effects on the body. This study aimed to investigate nitrate intake's effect on quadricep muscle oxygen saturation (StO2) of semi-professional soccer players during a repeated speed test (RSA). In a randomized, crossover design, 10 semi-professional soccer men players (21.3 ± 0.9yrs) performed two conditions: In one they consumed a nitrate-rich concentrated beetroot juice (250 mL/150 mg of NO3−) and in the other a placebo, 2h before a repeated sprint test. StO2 of the right vastus lateralis muscle was measured by near-infrared spectroscopy. A paired samples t-test was used to compute any differences in the subjects’ performance on the StO2 and on RSA test. The level of significance was set at p < 0.05. The supplementation of nitrates limited the decrease in muscle oxygenation during the six sprints of RSA test (p < 0.001) and also, there seemed to be a tendency for limited the decrement of performance on RSA test (t = -1.586, p = 0.157, η2 = 0.218). In conclusion, acute nitrate supplementation reduces the decrement of muscle oxygenation during exercise with repeated sprints and leads to a tendency of fatigue resistance during repeated sprints under controlled situations. Nitrate supplementation may have an ergogenic effect during exercise with repeated sprints via the higher muscle oxygenation.

TThis study aims to assess: (i) the morning -to- evening variability in body temperature, ball throwing velocity (BTV), shooting address, explosive lower-body power, strength power, and the repeated sprint ability (RSA) among male handball players; and (ii) the diurnal variations according to players' positions. Twenty-two participants assigned in players of thefront line (FL; N=11) and rear line (RL; N=11) completed assessments at 8:00 a.m. and 6:00 p.m., on two occasions dispersed throughout one week. Diurnal variations in BTV (p < 0.001), 1-RM Back Half Squat test (p < 0.001), and the counter movement jump (CMJ) test (p < 0.01) were recorded in the whole population. Specifically, morning -to- evening variabilities in BTV were noted in the FL (p < 0.05) and RL players (p < 0.001), with greater values observed in RL (p < 0.001). Significant variations were also observed in the 1-RM back half squat at RL (p < 0.01), and in CMJ (p < 0,01) and RSA (p < 0.05) at FL players. In conclusion, diurnal variations were higher in the evening compared to morning hours in players of RL in BTV and the explosive lower-body power, and in players of FL in CMJ and RSA performances. [ABSTRACT FROM AUTHOR]

This research aimed at finding out the effectiveness of a 6-week training program aimed at developing repeated sprint ability (RSA) of U19 soccer players. The experimental group consisted of elite youth soccer players (n = 14) in the club of the Slovak First league U19. Three different tests were used to obtain data: Bangsbo sprint test, 10-m sprint and 20-m sprint test. Players completed a 6-week control period, with a predominance of specific stimuli without targeted RSA development through repeated sprints. Subsequently, they completed a 6-week experimental period which was complemented by an experimental factor focused on developing of RSA using repeated 20 m sprints. After the control period, players worsened in RSA parameters: RSAmean (p = 0.02, r = 0.61) RSAbest (p = 0.03, r = 0.59) RSAworst (p = 0.07, r = 0.21) RSAFI (p = 0.29, r = 0.07). After the experimental period, the players improved their performance in the parameters of RSA: RSAmean (p = 0.001, r = 0.80) RSAbest (p = 0.001, r = 0.82) RSAworst (p = 0.001, r = 0.78) RSAFI (p = 0.12, r = 0.31). There was an improvement in the acceleration speed in the 10-m sprint test (p = 0.02, r = 0.60) and in the 20-m sprint test (p = 0.002, r = 0.63). According to the results, the effectiveness of the speed-endurance training program was determined. We proved the necessity of using non-specific stimuli in developing repeated sprint ability in soccer players. [ABSTRACT FROM AUTHOR]

Individual variations in peripheral oxygen saturation (SpO 2 ) during repeated sprints in hypoxia and their impact on exercise performance remain unclear despite fixed external hypoxic stimuli (inspired oxygen fraction: FiO 2 ). This study examined SpO 2 individual variations during repeated sprints in hypoxia and their impact on exercise performance. Thirteen highly-trained sprint runners performed 10 × 10-s cycle sprints with 30-s passive recoveries in normobaric hypoxia (FiO 2 : 0.150). Mean power output (MPO), post-sprint SpO 2 , and heart rate for each sprint were assessed. Sprint decrement score (S dec ), evaluating fatigue development, was calculated using MPO variables. Participants were categorized into a high saturation group (HiSat, n  = 7) or a low saturation group (LowSat, n  = 6) based on their mean post-sprint SpO 2 (measured 10-15 s after each sprint). Individual mean post-sprint SpO 2 ranged from 91.6% to 82.2%. Mean post-sprint SpO 2 was significantly higher ( P  < 0.001, d  = 1.54) in HiSat (89.1% ± 1.5%) than LowSat (84.7% ± 1.6%). A significantly larger decrease in S dec ( P  = 0.008, d  = 1.68) occurred in LowSat (-22.3% ± 2.3%) compared to HiSat (-17.9% ± 2.5%). MPO ( P  = 0.342 d  = 0.55) and heart rate ( P  = 0.225 d  = 0.67) did not differ between groups. There was a significant correlation ( r  = 0.61; P  = 0.028) between SpO 2 and S dec . In highly-trained sprint runners, individual responses to hypoxia varied widely and significantly affected repeated sprint ability, with greater decreases in SpO 2 associated with larger performance alterations (i.e., larger decrease in S dec )., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2024 Takei, Muraki, Girard and Hatta.)

We examined physiological responses and fatigue in adolescent boys and girls during a repeated shuttle-sprint running test in a school setting. We also compared three calculation methods to assess fatigue during repeated sprints: the fatigue index (FI), the percent sprint decrement (Sdec), and the slope of performance decrement (SlopeD). Twenty-six adolescent students (10 girls and 16 boys, age: 15.3 ± 0.5 y) performed six 30 m sprints with a 180° change of direction at 15 m, interspersed with 10 s of recovery. Blood lactate (BL), heart rate (HR) and countermovement jump performance (CMJ) were measured before and after the sprint test. Boys achieved significantly faster sprint times (11.7% to 14.8% faster than girls in all sprints, p < 0.01), and had higher post-test BL compared with girls (14.0 ± 2.9 vs. 11.3 ± 3.2 mmol/L; p = 0.02; d = 0.93). However, all fatigue indices (FI, Sdec and SlopeD) were similar in boys and girls (FI = 11.5 ± 5.0 vs. 11.5 ± 5.0; SlopeD = 10.6 ± 4.8 vs. 14.5 ± 5.1; Sdec = 5.6 ± 2.2 vs. 7.3 ± 2.2, in boys and girls, respectively, p > 0.05 for all) and were highly correlated with each other (r = 0.86 to 0.97, p < 0.01). CMJ was higher in boys (p < 0.05), but CMJ performance dropped similarly from pre- to post-test in boys and girls (13.7 ± 7.0%, p < 0.01). In conclusion, neuromuscular fatigue during and after repeated shuttle-sprint running is similar in boys and girls, despite the faster sprint times, higher CMJ and higher BL in boys. SlopeD may be used as an alternative index to quantify fatigue during repeated shuttle-sprinting, as it takes into account performance in all sprints and may provide an average sprint-by-sprint performance drop.

Warm-up routines include various tasks focused on the peripheral contractile properties and nervous motor command. This present study was aimed at investigating the acute effects of different warm-up routines, emphasizing either peripheral (post-activation performance enhancement, PAPE) or central (motor imagery, MI) contributions on sport-specific tasks. Eleven young female athletes took part in this cross-over, randomized, controlled trial. They underwent three experimental sessions composed of a standardized warm-up followed by 10 min of (1) rest (CONTROL), (2) maximal concentric leg press (PAPE), or (3) mental repetitions of sprint tasks (MI). Post-tests consisted of reaction time, arrowhead agility test, 20 m sprint, repeated sprint ability, and NASA-TLX fatigue questionnaire. PAPE and MI significantly enhanced the arrowhead agility test (p < 0.001 and p = 0.012, respectively) and repeated sprint ability (p = 0.002 and p = 0.035, respectively) compared to CONTROL, without any difference between PAPE and MI. The 20 m sprint time was better after PAPE as compared to MI (p = 0.005) and CONTROL (p < 0.001), without any difference between MI and CONTROL. Reaction time and the NASA-TLX questionnaire were not affected by the warm-up modalities (p > 0.05). PAPE was the most efficient to optimize warm-up due to its greater peripheral contribution that would improve muscle contractility. MI specifically improved the imagined tasks mostly by central contribution.

Taylor, L and Jakeman, JR. The impact of a repeated sprint training program on performance measures in male field hockey players. J Strength Cond Res 36(7): 1984–1988, 2022—Sprint interval training (SIT) has been shown to be effective at improving athletic performance in laboratory studies, but the efficacy of SIT programs incorporated into normal training schedules is poorly considered. This study aimed to investigate the impact of a running SIT intervention applied to competitive athletes within a training program and to consider whether an uphill or flat (horizontal) SIT protocol had different effects on performance changes over time. Eighteen male hockey players (mean ± SD : age, 20.7 ± 0.9 years; hockey training experience, 9.9 ± 3.0 years) completed 2 sessions of SIT per week for 8 weeks, with intensity progressively increasing from 6 sprints in week 1 to 12 sprints in week 8. Subjects were randomly allocated to a flat or uphill (6% gradient) training condition (n = 9) and completed 30-m maximal sprint efforts with a 30-second recovery. Performance measures, including squat jump, 30-m sprint speed, and repeated sprint time, all improved significantly (p ≤ 0.05). Squat jump performance improved by 3.84 (d = 0.8) and 3.55 (d = 0.7) in the flat and uphill groups, respectively. Thirty-meter sprint speed improved by 0.06 (d = −0.4) and 0.10 (d = −0.7), and repeated sprint performance also improved, with the fastest of recorded sprints after intervention being 0.06 and 0.04 faster in the flat and uphill groups, respectively. Supplementing a normal hockey training week with SIT can have a positive impact on performance measures in male university hockey players. Furthermore, using an uphill training modality had a small, nonsignificant additional positive effect to some performance adaptations. [ABSTRACT FROM AUTHOR]

Legerlotz, K, Kittelmann, J, Dietzel, M, Wolfarth, B, and Bohlke, N. Ice hockey-specific repeated shuttle sprint test performed on ice should not be replaced by off-ice testing. J Strength Cond Res 36(4): 1071-1076, 2022-Although the importance of sport-specific testing has been stated in various studies, the application of standard tests that are little related to the requirements in competition is still widespread in performance diagnostics. Furthermore, the actual exercise mode in testing often deviates from the exercise mode in competition. The aim of this study was therefore to investigate how the performance in an ice hockey mimicking repeated sprint shuttle test conducted off-ice (RSS) differs from the on-ice performance (RISS). The two performance tests were completed by 21 male junior ice hockey players within one week. Anaerobic fatigue was significantly larger in RISS and did not correlate with RSS, whereas best run, mean run, total run time, turn and fly time, and total times in all three shifts correlated moderately. Although the best and mean run times did not differ, these times were achieved with different strategies depending on the test condition, indicated by significantly different split times. Aerobic fatigue in shift 3 was the only parameter where the off-ice measurement correlated strongly with the on-ice measurement. Our results imply that an off-ice test does not predict on-ice performance with sufficient precision, strongly advocating performance testing in the exercise mode used in competition. [ABSTRACT FROM AUTHOR]