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During supramaximal exercise, exacerbated at exhaustion and in hypoxia, the circulatory system is challenged to facilitate oxygen delivery to working tissues through cerebral autoregulation which influences fatigue development and muscle performance. The aim of the study was to evaluate the effects of different levels of normobaric hypoxia on the changes in peripheral and cerebral oxygenation and performance during repeated sprints to exhaustion. Eleven recreationally active participants (six men and five women; 26.7 ± 4.2 years, 68.0 ± 14.0 kg, 172 ± 12 cm, 14.1 ± 4.7% body fat) completed three randomized testing visits in conditions of simulated altitude near sea-level (∼380m, FIO2 20.9%), ∼2000m (FIO2 16.5 ± 0.4%), and ∼3800m (FIO2 13.3 ± 0.4%). Each session began with a 12-min warm-up followed by two 10-s sprints and the repeated cycling sprint (10-s sprint: 20-s recovery) test to exhaustion. Measurements included power output, vastus lateralis, and prefrontal deoxygenation [near-infrared spectroscopy, delta (Δ) corresponds to the difference between maximal and minimal values], oxygen uptake, femoral artery blood flow (Doppler ultrasound), hemodynamic variables (transthoracic impedance), blood lactate concentration, and rating of perceived exertion. Performance (total work, kJ; -27.1 ± 25.8% at 2000m, p < 0.01 and -49.4 ± 19.3% at 3800m, p < 0.001) and pulse oxygen saturation (-7.5 ± 6.0%, p < 0.05 and -18.4 ± 5.3%, p < 0.001, respectively) decreased with hypoxia, when compared to 400m. Muscle 1 hemoglobin difference ([Hbdiff]) and 1 tissue saturation index (TSI) were lower (p < 0.01) at 3800m than at 2000 and 400m, and lower 1 deoxyhemoglobin resulted at 3800m compared with 2000m. There were reduced changes in peripheral [Δ[Hbdiff], ΔTSI, Δ total hemoglobin ([tHb])] and greater changes in cerebral (Δ[Hbdiff], Δ[tHb]) oxygenation throughout the test to exhaustion (p < 0.05). Changes in cerebral deoxygenation were greater at 3800m than at 2000 and 400m (p < 0.01). This study confirms that performance in hypoxia is limited by continually decreasing oxygen saturation, even though exercise can be sustained despite maximal peripheral deoxygenation. There may be a cerebral autoregulation of increased perfusion accounting for the decreased arterial oxygen content and allowing for task continuation, as shown by the continued cerebral deoxygenation. [ABSTRACT FROM AUTHOR]

The present study assessed if differences in the metabolic profile, inferred from the anaerobic speed reserve (ASR), would influence the dynamics of heart rate recovery (HRR) after two modes of exercise. Thirty-nine physical education students (14 females and 25 males) volunteered for this study. Participants carried out three separate testing sessions to assess maximal sprinting speed (MSS, 1st session), repeated sprint ability (RSA, 2nd session) and maximal aerobic speed (MAS) using the Université of Montreal Track Test (UMTT, 3rd session). ASR was defined as the difference between MSS and MAS. Heart rate was continuously registered throughout the tests and during the 5-min post-test recovery. To evaluate the influence of ASR on post-exercise, HRR comparisons between ASR-based groups [high ASR vs. low ASR] and sex groups (males vs. females) were performed. Significant differences (P < 0.05) were found between high ASR and low ASR groups of the same sex for indices of relative HRR after the RSA and UMTT. In addition, after the RSA test, males from the high ASR group had a significantly slower HRR kinetics compared with the males of the low ASR (P < 0.05) and the females of high ASR (P < 0.05); whereas females of the high ASR groups had a faster HRR kinetics compared with the females of low ASR group (P < 0.05). Our results showed that in males, post-exercise HRR could be related to the ASR, whereas in females, the influence of ASR is less clear. [ABSTRACT FROM PUBLISHER]

This study aims to investigate the performance changes in 19 well-trained male rugby players after repeat-sprint training (six sessions of four sets of 5 x 5 s sprints with 25 s and 5 min of active recovery between reps and sets, respectively) in either normobaric hypoxia (HYP; n = 9; FIO2 = 14.5%) or normobaric normoxia (NORM; n = 10; FIO2 = 20.9%). Three weeks after the intervention, 2 additional repeat-sprint training sessions in hypoxia (FIO2 = 14.5%) was investigated in both groups to gauge the efficacy of using "top-up" sessions for previously hypoxic-trained subjects and whether a small hypoxic dose would be beneficial for the previously normoxic-trained group. Repeated sprint (8 x 20m) and Yo-Yo Intermittent Recovery Level 1 (YYIR1) performances were tested twice at baseline (Pre 1 and Pre 2) and weekly after (Post 1-3) the initial intervention (intervention 1) and again weekly after the second "top-up" intervention (Post 4-5). After each training set, heart rate, oxygen saturation, and rate of perceived exertion were recorded. Compared to baseline (mean of Pre 1 and Pre 2), both the hypoxic and normoxic groups similarly lowered fatigue over the 8 sprints 1 week after the intervention (Post 1: -1.8 ± 1.6%, -1.5 ± 1.4%, mean change ± 90% CI in HYP and NORM groups, respectively). However, from Post 2 onwards, only the hypoxic group maintained the performance improvement compared to baseline (Post 2: -2.1 ± 1.8%, Post 3: -2.3 ± 1.7%, Post 4: -1.9 ± 1.8%, and Post 5: -1.2 ± 1.7%). Compared to the normoxic group, the hypoxic group was likely to have substantially less fatigue at Post 3-5 (-2.0 ± 2.4%, -2.2 ± 2.4%, -1.6 ± 2.4% Post 3, Post 4, Post 5, respectively). YYIR1 performances improved throughout the recovery period in both groups (13-37% compared to baseline) with unclear differences found between groups. The addition of two sessions of "top-up" training after intervention 1, had little effect on either group. Repeat-sprint training in hypoxia for six sessions increases repeat sprint ability but not YYIR1 performance in well-trained rugby players. [ABSTRACT FROM AUTHOR]

This study reviewed the literature discussing repeated sprint ability (RSA) in Australian Football (AF) in order to create recommendations that coaches can apply in the field. The review was conducted at the University of Canberra Library using books, journals and online journals. Movement demands of AF were examined with results showing that the current RSA testing practice of 6x30m is not sport specific. A revised test of 10x20m is proposed, as this more accurately represents the movement demands of AF. Understanding the fatigue mechanisms that underpin RSA, and how best to train them is vital. Training should incorporate a wide variety of interval running, with work to rest ratio's varying from 1:10 with 30 seconds work, to 2:1 with 120 seconds work. Specific RSA drills such as 3 x ([2 x 10, 15, 20m sprint: 15 sec rest]: 4.5 min rest) should be included. Undulating resistance training programs should be implemented to improve strength, power and muscle endurance. The repetition range will vary depending on specific athlete's needs and training history. Plyometric training, including weighted sled sprints, are essential to improve the stretch shortening cycle and increase acceleration. A maximum of 140 landings per session during pre-season and a maximum of 100 landings in season are advised. Incorporating small sided games (SSG) into training sessions can improve RSA whilst concurrently training match awareness and skills. One proposed SSG session is a 4 vs. 4 game, duration 6 x 4 minutes performed at >90% maximum heart rate with 3 minutes active recovery at <60% maximum heart rate. Specific details are provided for each of these training modes and where possible have been adapted specifically for AF. [ABSTRACT FROM AUTHOR]

We aimed to determine the gains in explosive movements of male junior soccer players induced by incorporating an 8-week plyometric training program (PTP) into a standard soccer conditioning regimen 5 months after the beginning of the competitive season. Our hypothesis was that PTP would enhance explosive movements, and thus sprint running, repeated shuttle sprint ability (RSSA), agility and the ability to make repeated changes of direction (RCOD). A group of junior soccer players were randomly divided into 2 groups: an experimental group (E, n = 15, age 15.7 ± 0.2 years) and a control group (C, n = 13, age 15.8 ± 0.2 years). The participants in E and C performed training exercises and matches together, but for an 8-week period in the latter part of the season, the experimental group replaced a part of the normal regimen (the tactical session) by a biweekly course of PTP (hurdle and drop jumps). Two familiarization sessions were held 2 weeks before definitive testing. The ability of the players was assessed by 3 agility tests (a sprint test with 1808 turns, a 9-3-6-3-9 m sprint with backward and forward running, and a four 5-m sprint test with turns); 2 repeated sprint tests (RSSA and RCOD); and running times over 5-, 1 0-, 20-, 30-, and 40-m distances. Participants in E showed gains relative to C in sprint times (p ≤ 0.05 for 5, 1 0, and 20 m), and 2 of 3 the RCOD parameters (RCOD best, p ≤ 0.001 ; RCOD total, p ≤ 0.05). However, with the pattern of plyometric training that we adopted, and perhaps because participants were in good initial physical condition, the agility and RSSA test scores remained unchanged. Nevertheless, we conclude that our PTP can be commended to junior soccer players as a means of improving important components of their physical performance. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare the different modes to quantifying the training load in small-sided game (SSG), repeated sprint ability (RSA), and simulated match (SM). Ten female futsal players participated, which was conducted in three sessions. In all the sessions, heart rate, rating of perceived effort, and total duration of the session to calculate the training impulse (TRIMP), and internal load (IL) were recorded. Significant differences in HR max were observed between SM (196 beats·min-1) and SSG (186 beats·min-1), and also between SM and RSA (185 beats·min-1). However, no differences were found in HR max. Differences were found only in IL between SSG (103 a.u) and SM (222 a.u) and also between SSG and RSA (156 a.u). The RPEBorg presented difference only between RSA (13.5 a.u) and SSG (9.5 a.u) and SM (12 a.u). The results demonstrate that sessions with SM and SSG show similar psychological and physiological responses, but lower than observed in RSA training sessions. Thus, these procedures can be employed to improve physical abilities at different periods of futsal training. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the association between physiological variables related to physical fitness determined by continuous straight running on a treadmill (peak velocity on treadmill: PVTRE, maximum oxygen uptake: VO2max, minimum velocity needed to reach VO2max: vVO2max, and velocity at the anaerobic threshold: vAT) and intermittent running with directional changes (peak velocity: PV) and repeated sprint ability (RSA) in soccer players. Twenty-nine athletes (17.9 ± 1.0 years, 178.7 ± 5.2 cm, 73.6 ± 6.7 kg, and 11.1 ± 1.3% body fat) performed the following tests on different days: 1) incremental protocol on a treadmill to determine PVTRE, VO2max, vVO2max, and vAT; 2) incremental intermittent running test to determine PV, and 3) Bangsbo test to evaluate RSA and to determine the mean time (MT), fastest time (FT), and fatigue index (FI). Pearson’s correlation coefficient was used and a level of significance of 5% was adopted. PV obtained in the intermittent running test showed a higher correlation with MT and FT of the RSA test (r = -0.70, p < 0.01; r = -0.51, p < 0.01, respectively) than vVO2max (r = -0.43, p < 0.05; r = -0.14 p > 0.05) and PVTRE (r = -0.42, p < 0.05; r =-0.14, p > 0.05) determined by straight running on a treadmill. In conclusion, the relationship between physical fitness and RSA depends on the type of protocol (continuous line running vs. intermittent with directional changes) and the aerobic index used (capacity vs. power).

O objetivo do estudo foi investigar a associação entre variáveis fisiológicas relacionadas à aptidão aeróbia determinadas de forma contínua em corrida na esteira (pico de velocidade da esteira: PVEST, consumo máximo de oxigênio: VO2max, velocidade correspondente ao VO2max: vVO2max e velocidade referente ao limiar anaeróbio: vLAn) e intermitente com mudança de sentido (pico de velocidade: PV) com a capacidade de sprints repetidos (CSR) em jogadores de futebol. Vinte e nove atletas (17,9 ± 1,0 anos; 178,7 ± 5,2 cm; 73,6 ± 6,7 kg; 11,1 ± 1,3 % gordura) realizaram, em dias diferentes, os seguintes testes: 1) protocolo incremental na esteira rolante para determinar o PVEST, o VO2max, a vVO2max e a vLAn; 2) teste incremental de corrida intermitente (TCar) para determinar o PV e 3) teste de Bangsbo para avaliar a CSR e determinar o tempo médio (TM), melhor tempo (MT) e índice de fadiga (IF). Foi realizada a correlação linear de Pearson, adotando--se o valor de p0,05) e o PVEST (r= -0,42, p0,05) determinados no modelo de corrida em linha reta na esteira. Pode-se concluir que a relação entre aptidão aeróbia e CSR é dependente do tipo de protocolo utilizado (contínuo em linha reta vs intermitente com mudança de sentido) e da variável aeróbia utilizada (capacidade vs potência).

Anaerobic power is a significant predictor of acceleration and top speed in team sport athletes. Historically, these findings have been applied to ice hockey although recent research has brought their validity for this sport into question. As ice hockey emphasizes the ability to repeatedly produce power, single bout anaerobic power tests should be examined to determine their ability to predict on-ice performance. We tested whether conventional off-ice anaerobic power tests could predict on-ice acceleration, top speed, and repeated shift performance. Forty-five hockey players, aged 18-24 years, completed anthropometric, off-ice, and on-ice tests. Anthropometric and off-ice testing included height, weight, body composition, vertical jump, and Wingate tests. On-ice testing consisted of acceleration, top speed, and repeated shift fatigue tests. Vertical jump (VJ) (r = -0.42; r = -0.58), Wingate relative peak power (WRPP) (r = -0.32; r = -0.43), and relative mean power (WRMP) (r = -0.34; r = -0.48) were significantly correlated (p ≤ 0.05) to on-ice acceleration and top speed, respectively. Conversely, none of the off-ice tests correlated with on-ice repeated shift performance, as measured by first gate, second gate, or total course fatigue; VJ (r = 0.06; r = 0.13; r = 0.09), WRPP (r = 0.06; r = 0.14; r = 0.10), or WRMP (r = -0.10; r = -0.01; r = -0.01). Although conventional off-ice anaerobic power tests predict single bout on-ice acceleration and top speed, they neither predict the repeated shift ability of the player, nor are good markers for performance in ice hockey. [ABSTRACT FROM AUTHOR]

Purpose: Compelling evidence suggests larger performance decrements during hypoxic versus normoxic repeated sprinting. Yet the underlying mechanical alterations have not been thoroughly investigated. Therefore, we examined the effects of different levels of normobaric hypoxia on running mechanical performance during repeated treadmill sprinting. Methods: Thirteen team sport athletes performed eight 5-s sprints with 25 s of passive recovery on an instrumented treadmill in either normoxia near sea level (SL; FiO2 = 20.9%), moderate normobaric hypoxia (MH; FiO2 = 16.8%; corresponding to ~1800 m altitude), or severe normobaric hypoxia (SH; FiO2 = 13.3%; ~3600 m). Results: Net power output in the horizontal direction did not differ (P > 0.05) between conditions for the first sprint (mean ± SD, pooled values: 13.09 ± 1.97 W⋅kg-1) but was lower for the eight sprints in SH compared with SL (-7.3% ± 5.5%, P < 0.001) and MH (-7.1% ± 5.9%, P < 0.01), with no difference between SL and MH (+0.1% ± 8.0%, P = 1.00). Sprint decrement score was similar between conditions (pooled values: -- 11.4% ± 7.9%, P = 0.49). Mean vertical, horizontal, and resultant ground reaction forces decreased (P < 0.001) from the first to the last repetition in all conditions (pooled values: -2.4% ± 1.9%, -8.6% ± 6.5%, and --2.4% ± 1.9%). This was further accompanied by larger kinematic (mainly contact time: +4.0% ± 2.9%, P < 0.001, and +3.3% ± 3.6%, P < 0.05, respectively; stride frequency: -2.3% ± 2.0%, P < 0.01, and -2.3% ± 2.8%, P < 0.05, respectively) and spring-mass characteristics (mainly vertical stiffness: -6.0% ± 3.9% and -5.1% ± 5.7%, respectively, P < 0.01) fatigue-induced changes in SH compared with SLandMH. Conclusion: In SH, impairments in repeated sprint ability and in associated kinetics/kinematics and spring-mass characteristics exceed those observed near SL and in MH (i.e., no or minimal difference). Specifically, SH accentuates the repeated sprint ability fatigue-related inability to effectively apply forward-oriented ground reaction force and to maintain vertical stiffness and stride frequency. [ABSTRACT FROM AUTHOR]

The purpose of this study is to investigate the age-related differences in the repeated sprint ability and fatigue index in Turkish girl athletes in puberty. 36 youth girls (11 age group n=13, 12 age group n=16, 13 age group n=7) participated in this study voluntarily. Repeated sprint ability of girls was determined by 7 × 30 m running repeated sprint test with 25 sec active recovery durations. Body composition was measured in terms of height, weight and body mass index. The height values were found to be slightly lower in 11 age group compared to 12 and 13 age groups (p<0.05), but there was no difference between 12 and 13 age groups in height values (p>0.05). There were significant differences among the three groups in weight values (p<0.05). Best sprint time, total sprint time and the repeated sprint decrement/fatigue index were determined for each player. One way analysis of variance indicated significant differences in the best sprint time (F (2.34) = 35.78, p<0.05) and total sprint time (F (2.34) = 21.73, p<0.05) among 11, 12 and 13 age groups. According to the Tukey analysis results, these differences arose from 11 age group for both the best sprint time and total sprint time. No significant difference was observed in fatigue index among the three groups (p>0.05). Our results indicated that the repeated sprint ability, and fatigue index are independent from age and other variables such as height, weight and body mass index, while the best sprint time and total sprint time improve with age. [ABSTRACT FROM AUTHOR]

Physiological responses (intensity and recovery kinetics) and well-being indices were examined during a 4-day FIFA international tournament. Ten outfield New Caledonian players (age: 25.5 ± 3.8 years; height: 170 ± 7 cm; weight: 70.7 ± 8.6 kg) were assessed during the four matches. Players’ aerobic and anaerobic capacities were measured before the tournament while heart rate (HR), intra-matches recovery and well-being indices (Hooper index) were measured throughout the tournament. HR (168 ± 8 bpm), exercise intensity (83.4 ± 2.3% of HR reserve) and recovery indices were similar throughout the tournament. Well-being indices were largely alike during the tournament while rating of perceived exertion increased throughout the tournament that was not associated with HR or well-being indices. High aerobic and anaerobic capacities were associated with high match intensities and slow recovery indices. In summary, match intensity assessed by HR, recovery kinetics and well-being of Oceanian futsal players were not modified during a 4-day FIFA futsal tournament. Assessment of aerobic and anaerobic capacities may be useful to select players for optimal performance during this type of international tournament. [ABSTRACT FROM AUTHOR]

Purpose: We examined effects of a three-game, 1-week microcycle (G1, G2, G3) on recovery of performance and inflammatory responses in professional male footballers.Methods: Players were randomized into an experimental (EXP; N = 20) and a control group (CON; N = 20). Blood was drawn and repeated sprint ability (RSA), muscle soreness and knee range of motion (KJRM) were determined pre- and post-games and during recovery.Results: High-intensity running during G2 was 7-14% less compared to G1 and G3. RSA declined in EXP by 2-9% 3 days post-game with G2 causing the greatest performance impairment. In EXP, game play increased muscle soreness (~sevenfold) compared to CON with G2 inducing the greatest rise, while KJRM was attenuated post-game in EXP compared to CON (5-7%) and recovered slower post G2 and G3 than G1. CK, CRP, sVCAM-1, sP-Selectin and cortisol peaked 48 h post-games with G2 eliciting the greatest increase. Leukocyte count, testosterone, IL-1β and IL6 responses, although altered 24 h post each game, were comparable among games. Plasma TBARS and protein carbonyls rose by ~50% post-games with G2 eliciting the greatest increase 48 h of recovery. Reduced to oxidized glutathione ratio declined for 24 h post all games with G2 displaying the slowest recovery. Total antioxidant capacity and glutathione peroxidase activity increased (9-56%) for 48 h in response to game play.Conclusion: In summary, post-game performance recovery and inflammatory adaptations in response to a three-game weekly microcycle displayed a different response pattern, with strong indications of a largest physiological stress and fatigue after the middle game that was preceded by only a 3-day recovery. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyse the influence of the repeated sprint ability (RSA) training load increase on the mood states in young tennis players. Thirty tennis players (15.78 ± 1.58 years) took part in this training program (7 weeks). The subjects were divided into 3 groups: G1, specific tennis training and an increase of 8.3% of RSA training volume; G2 specific tennis training and an increase of 16.6% of RSA training volume; G3, only specific tennis training. The specific tennis training volume was controlled and equated for this period, and all the subjects also filled out a weekly questionnaire to establish the profile of mood states (POMS, Balaguer, Fuentes, Meliá, García-Mérita & Pons, 1995). The results showed changes in G1 and G2. Whereas tension and fatigue scores increased at the end of the training program in G1 (p < .05), scores of tension, depression, hostility and fatigue were higher at the beginning than at the end of the training program in G2 (p < .05). There were no significant changes in G3 for any variable. The different evolution of subjects' mood states based on RSA training volume performed shows the need for monitoring internal load to fit this training. [ABSTRACT FROM AUTHOR]

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The purpose of this study was to investigate the effect of a maximal shuttle-run shock microcycle in hypoxia on repeated sprint ability (RSA, 6 × 40-m (6 × 20 m back and forth, 20″ rest in between)), Yo-Yo-intermittent-recovery (YYIR) test performance, and redox-status. Fourteen soccer players (age: 23.9 ± 2.1 years), randomly assigned to hypoxia (∼3300 m) or normoxia training, performed 8 maximal shuttle-run training sessions within 12 days. YYIR test performance and RSA fatigue-slope improved independently of the hypoxia stimulus ( p < 0.05). Training reduced the oxidative stress level (−7.9%, p < 0.05), and the reduction was associated with performance improvements ( r = 0.761, ΔRSA; r = −0.575, ΔYYIR, p < 0.05). [ABSTRACT FROM AUTHOR]

The objective of this study was to determine in amateur handball players, the changes in fitness capacities and physiological data, during a series of three consecutive matches, as well as the rates of restoration reached after a 24-hour recovery. The study sample included 17 senior players (23.5 ± 0.7 years; 176.4 ± 6.7 cm; 73.4 ± 9.2 kg). They were randomly distributed in two teams A and B, to play the series of experimental matches, 24 hours apart. The players ran a 30-m sprint and took repeated sprint ability test, before the first and at the end of the third match. We measured the squat and counter movement jump heights, the physiological parameters before and just at the end of all the matches. The performances at the 30-m sprint and jump tests decreased non-significantly (p > 0.05) between the beginning and the end of the three matches. The repeatedsprint ability was reduced by 9.3% between the initial measurement and that of the end of the 3rd match. After a 24-hour recovery, the difference with the initial performance was always of the same order as that of the end of the 3rd match. In the context of this study, there was no cumulated effect of the matches on the fitness capacities measured. The results suggest that the trainers systematically integrate in the training schedules of these handball players, physical preparation and fitness work items that favour fast inter-efforts recovery. [ABSTRACT FROM AUTHOR]

This study investigated whether ischemic preconditioning (IPC) in a trained population affected repeated sprint performance. A secondary aim was to assess responses according to gender. Sixteen (nine females and seven males) well trained team sport athletes took part in a randomised crossover study design. Participants underwent an IPC and placebo treatment involving three periods of 5 min occlusion applied unilaterally (3 × 5 min occlusion to each leg) at either 220 mmHg or 50 mmHg. Each period of occlusion was followed by 5 min reperfusion. Following treatment 5 × 6 s maximal effort sprints were undertaken on a cycle ergometer against 7.5% body mass, each interspersed by 24 s recovery. Measured parameters included peak power, total power, percentage decrement, post-exercise blood lactate and ratings of perceived exertion. Nor within subject main effect for IPC was observed, neither was there an interaction effect with gender. Effect sizes were trivial (ES < 0.2) with the exception of a moderate (ES < 1.2) change in post-exercise blood lactate in the female cohort (1.6 ± 0.4 mmol−1lower following IPC). Results suggest no benefit to team sport players in utilising IPC as a means of enhancing repeated sprint performance. A lower blood lactate response in female participants following IPC may suggest improved blood flow through vasodilation. [ABSTRACT FROM PUBLISHER]

The aim of this study was to investigate the effect of a total sleep deprivation (TSD) on the egocentric distance estimation following a fatiguing task (i.e. sprint repetitions). Ten soccer players (age: 22.8 ± 1.3 years; weight: 72. 8 ± 10 .5 kg; height: 1.8 ± 0.03 m) were volunteered to participate in the study. Subjects were invited to estimate different distances in two different sessions (i) following a reference night and (ii) following a night of TSD. The distance estimation consists to perceive three different distances (15, 25, and 35 m) before and after a repeated sprint exercise on a cycloergometer. The results demonstrated a significant effect of TSD on the perception of egocentric distance (F(1.9) = 11.22,p < 0.01). Indeed, the results showed an underestimation (compression of the real distance) of all distances at rest and following the repeated sprint exercise. Additionally, the underestimation was more acute after the fatiguing task. TSD affects the estimation of egocentric distance by soccer players at rest and following fatiguing task. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the relationships between repeated explosive effort sequences (20 + 20 m shuttle sprint with change of direction, kicking and jumping), metabolic response (lactate and ammonia), and fitness qualities (strength and endurance) in under-19 soccer players. 21 players completed: 1) sprint test: 30 m (T30 ) and 40 m (20 + 20 m) shuttle sprints; 2) countermovement jumps (CMJ); 3) maximal kicking; and 4) 9 repeated-explosive effort sequences (RES); 4) a progressive isoinertial loading test in full squat to determine the load which subjects achieved ~1 m · s −1 (V1 - load); 6) Yo-Yo Intermittent Recovery Test Level 1 (YYIRT-1). Mean sprint time of the 9 repeated sprints (RSAmean1–9 ) showed correlation with V 1 - load (r = − 0.52 [− 0.79, − 0.25]) metabolic response (lactate, r = 0.67 [0.47, 0.87] and ammonia, r = 0.53 [0.27, 0.79]). YYIRT-1 correlated with RSAmean1-9. (rw = − 0.78 [− 0.92, − 0.64]) when the body weight was controlled. Furthermore, the 3 first sprints (RSAmean1-3 ) correlated with RSAbest (r = 0.93 [0.88, 0.98]), V 1 -load (r = − 0.64 [ − 0.86, − 0.42]), and T30 (r = 0.63 [0.41, 0.85]). These results suggest that the soccer player’s lower body strength (V1 -load, jumping and sprinting) explains a large part of the performance in the first sequences, whereas the aerobic capacity, estimated through YYIRT-1, becomes more important to performance as the number of sprints is increases. [ABSTRACT FROM AUTHOR]

The article discusses the individual and team time-motion analyses of Italian elite women's basketball games. Topics include low- and high-intensity activities (HIAs) in basketball, such as running and jumping, respectively, the evaluation of players’ movement patterns during HIA, sprint activity, and repeated sprint events (RSEs), the analyses of live time (LT), stoppage time (ST), and half- and full-court actions in teams, and the frequency at which changes of activities occurred.

The article presents the results of a study conducted to determine the effectiveness of the cold-water immersion (CWI) over passive rest as an intervention and recovery strategy for muscle soreness and anaerobic performance following a Futsal match. Topics covered are the research methods and the conclusions drawn from two simulation matches and the conduct of muscle soreness assessment, counter movement jump (CMJ), repeated jump ability (RJA) and sprint running tests.

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

This study examined the effects of 8-weeks of in-season lower limb plyometric training on repeated-sprint ability (RSA), leg power and jumping performance in elite male handball players. Twenty-four participants (age 20 ± 0.3 years, body mass 89.1 ± 2.1 kg, height 1.88± 0.07 m, body fat 13.2 ± 1.3%) were randomly assigned to a control group (CG; n = 10, handball training only) or an experimental group (PG; n = 14, biweekly plyometric training, and handball training). The players were tested for RSA using a protocol of 6 x (2 x 15m) shuttle sprints, separated by 20 s of active recovery. Best time in a single trial (RSAbest), fastest total time (RSATT) and performance decrement (RSAdec) were determined. Leg power was determined by the peak power output (PP) during a 7-second all-out cycling test. Jump heights during the squat jump (SJ) and the countermovement jump (CMJ) were measured. Compared to the CG, PG significantly improved the RSAbest (p < 0.01), RSATT (p <0.01) and RSAdec (p < 0.001), average PP (p < 0.01) and all vertical jump performances (p < 0.001 for SJ and p <0.01 for CMJ). Biweekly plyometric training improved several aspects of RSA performance, leg power, and jumping performance during the season in elite male handball players. However, no interaction effect was found between the groups for the repeated sprint ability test (p = 0.062) or relative peak power (p=0.075). Coaches and strength and conditioning professionals should devote additional time for plyometric training in elite male handball players during the season to improve physical performance. [ABSTRACT FROM AUTHOR]

The article reports on research which investigated the effects a small-sided game training intervention had on the intermittent shuttle running performance, speed, and repeated sprint ability of elite rugby league players during the competitive phase of a rugby league season. Researchers evaluated the intervention with 10 players. They found that it was an effective method for improving the physical performance of elite rugby league players.

The article reports on research which was conducted to examine the interactive effects of recovery mode and duration on subsequent repeated short cycle sprint (RSS) performance. Researchers evaluated 10 male subjects who performed four randomized cycling trials, had a recovery period which was either active (AR) or passive (PR) and the performed more trials. They found that when rest periods are short, a PR strategy appears to optimize subsequent RSS performance. However, as the recovery duration increases, subsequent RSS performance appears to benefit from an AR strategy.

The article reports on research which was conducted to investigate the effect of incorporating stretches into a massage recovery treatment after a competitive basketball match on perceptual and physical markers of recovery. Researchers evaluated nine male and eight female national level basketball players who received a massage, a massage and stretching, or no treatment immediately after a competitive match. They found that women benefit slightly more from the combination treatment than men.

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

The article presents a comparison between the differences and changes occurred in the physical characteristics of professional and amateur rugby union players. Topics discussed include the nature of rugby union sport, features of speed, strength, power and body composition of players, and measurement of the physical characteristics of rugby players.

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., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Katsuhiro Koyama reports financial support was provided by Panasonic Corporation. co-author Yoshinori Tanaka is an employee of the Appliances Company, Panasonic Corporation., (© 2022 The Authors. Published by Elsevier B.V.)