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Acute effects of two different resistance circuit training protocols on performance and perceived exertion in semiprofessional basketball players. J Strength Cond Res 30(2): 407–414, 2016—This study aimed to investigate the acute effects of two different resistance circuit training protocols on basketball players' physical and technical performance and rating of perceived exertion (RPE). In a repeated-measures, crossover experimental design, 9 semiprofessional basketball players performed a Power Circuit Training (PCT; 45% 1RM) and a High-Resistance Circuit Training (HRC; 6RM), on consecutive weeks. Vertical and horizontal jump performance, 3-points shooting accuracy, repeated-sprint ability (RSA), agility, and upper body power output were measured before and after training. The RPE was assessed 20 minutes after resistance training. One-way repeated-measures analysis of variance showed performance decrements in vertical jump height and peak power, horizontal jump distance, 3-points percentage, bench-press power output, RSA total and ideal time, and agility T-Test at total time following HRC, but not PCT (p

International audience; 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; FiO 2 = 20.9%), moderate normobaric hypoxia (MH; FiO 2 = 16.8%; corresponding to ~1800 m altitude), or severe normobaric hypoxia (SH; FiO 2 = 13.3%; ~3600 m). Results: Net power output in the horizontal direction did not differ (P 9 0.05) between conditions for the first sprint (mean T SD, pooled values: 13.09 T 1.97 WIkg j1) but was lower for the eight sprints in SH compared with SL (j7.3% T 5.5%, P G 0.001) and MH (j7.1% T 5.9%, P G 0.01), with no difference between SL and MH (+0.1% T 8.0%, P = 1.00). Sprint decrement score was similar between conditions (pooled values: j11.4% T 7.9%, P = 0.49). Mean vertical, horizontal, and resultant ground reaction forces decreased (P G 0.001) from the first to the last repetition in all conditions (pooled values: j2.4% T 1.9%, j8.6% T 6.5%, and j2.4% T 1.9%). This was further accompanied by larger kinematic (mainly contact time: +4.0% T 2.9%, P G 0.001, and +3.3% T 3.6%, P G 0.05, respectively; stride frequency: j2.3% T 2.0%, P G 0.01, and j2.3% T 2.8%, P G 0.05, respectively) and spring-mass characteristics (mainly vertical stiffness: j6.0% T 3.9% and j5.1% T 5.7%, respectively, P G 0.01) fatigue-induced changes in SH compared with SL and MH. 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.

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 (p0.05). There were significant differences among the three groups in weight values (p0.05). 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

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: PV EST, 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 PV EST, 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 PV EST (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). 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: PV TRE, 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 PV TRE, 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 PV TRE (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).

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

We examined acute molecular responses in skeletal muscle to repeated sprint and resistance exercise bouts. Six men [age, 24.7 ± 6.3 yr; body mass, 81.6 ± 7.3 kg; peak oxygen uptake, 47 ± 9.9 ml·kg−1·min−1; one repetition maximum (1-RM) leg extension 92.2 ± 12.5 kg; means ± SD] were randomly assigned to trials consisting of either resistance exercise (8 × 5 leg extension, 80% 1-RM) followed by repeated sprints (10 × 6 s, 0.75 N·m torque·kg−1) or vice-versa. Muscle biopsies from vastus lateralis were obtained at rest, 15 min after each exercise bout, and following 3-h recovery to determine early signaling and mRNA responses. There was divergent exercise order-dependent phosphorylation of p70 S6K (S6K). Specifically, initial resistance exercise increased S6K phosphorylation (∼75% P < 0.05), but there was no effect when resistance exercise was undertaken after sprints. Exercise decreased IGF-I mRNA following 3-h recovery (∼50%, P = 0.06) independent of order, while muscle RING finger mRNA was elevated with a moderate exercise order effect ( P < 0.01). When resistance exercise was followed by repeated sprints PGC-1α mRNA was increased (REX1-SPR2; P = 0.02) with a modest distinction between exercise orders. Repeated sprints may promote acute interference on resistance exercise responses by attenuating translation initiation signaling and exacerbating ubiquitin ligase expression. Indeed, repeated sprints appear to generate the overriding acute exercise-induced response when undertaking concurrent repeated sprint and resistance exercise. Accordingly, we suggest that sprint-activities are isolated from resistance training and that adequate recovery time is considered within periodized training plans that incorporate these divergent exercise modes.

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 (ES0.2) with the exception of a moderate (ES1.2) change in post-exercise blood lactate in the female cohort (1.6 ± 0.4 mmol⁻¹ lower 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.

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Background: Several field-based team sports contain repeated, maximal effort sprints with varying rest lengths in between. This puts high demands on athletes’ metabolic and neuromuscular systems. Testing the anaerobic capacity of athletes is essential to improve and evaluate the progression. One test being utilised for assessing anaerobic capacity is the 300-yard shuttle run test. The test is field-based with stopwatches as the sole equipment. However, the test has not been properly tested for reliability. Aim: The aim of this bachelor thesis was therefore to investigate the reliability of the 300-yard shuttle run test. Methods: The study was performed with a test-retest method and included a familiarisation meeting, test session and retest session. Test subjects performed the 300-yard shuttle run test at two different occasions with seven or fourteen days in between. The intraclass correlation coefficient (ICC) and 95% confidence interval (CI) was utilised to quantify the reliability. An ICC>0.8 was considered acceptable. Results: 17 American football players participated in the study (median age 20, min. =18, max. =38 y; median weight 83, min. =67, max. =133 kg; median height 184, min. =169, max. =194 cm). The ICC for the test-retest was 0.97 (95% CI 0.91-0.99). Conclusion: Based on the results of this study 300-yard shuttle test is proposed as a test providing reliable results.

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 V1-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]), V1-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., Universidad Pablo de Olavide de Sevilla. Departamento de Deporte e Informática, Postprint

This study aimed to analyse a new repeated-sprint ability test (RST) for a motorised treadmill. The RST includes ten 15-s sprints at 23 km•h-1 interspersed by a 15-s static pause, followed by an exhaustive phase with increased sprint time and decreased recovery. The results would seem to indicate acceptable reliability for the key outcome variables (HR, RPE, number of completed sprints), good concurrent validity against VO2max and Yo-Yo IR2 performance, and sensitivity of the test to acute hypoxia exposure. In conclusion, the RST seems to provide an effective tool for repeated-sprint ability assessment in a laboratory setting.

Field-based team sports are considered intermittent sports in which short high-intensity activities are interspersed with short periods of recovery. Therefore, it is of utmost importance for a player to develop and maintain the high-level of endurance in speed and power which would enable him/her unchanged performance of high-intensity activities (HIA) throughout the entire match. Top-class soccer players perform more high-intensity running during the game compared to the moderate players. It seems that the main difference between the high and the low quality teams, in terms of physical conditioning, really depends on the ability to perform more sprints with less recovery periods. A single sprint is considered to be an anaerobic phosphate stimulus. Sufficient recovery period between each single sprint enables full phosphate restitution of an athlete and, therefore, following sprint would also be performed by using phosphate energy sources. However, when recovery periods between sprints are reduced to 20 or 30 seconds, the phosphate restitution is reduced, and the following sprint is performed with substantial contribution of anaerobic glycolysis. The energy system contribution during repeated sprints is heavily influenced by the duration of the sprints (or sprint distance), sprint number and duration of the recovery (Spencer et al., 2005). The repeated sprint ability is enhanced through various types of protocols (defined with distance or sprint duration, number of sprint repetitions and recovery period), but can also be altered by the exercise mode, recovery mode and physical readiness of an athlete.

Introduction Synthetic pitches are greatly increasing in popularity, but little is known on how playing on artificial turf rather than natural grass influences the physical performance in soccer. The aim of this study is to compare the two surfaces about the outcomes of a repeated sprint ability (RSA) test, shown as a valid indicator of match-related physical performance in soccer players2. We hypothesize that players that usually train on synthetic turf would perform better on that surface compared to natural grass. Methods Eighteen young male soccer players from two teams were recruited. Team A (n=11; 16.6  0.3 ys; 71.9  7.4 Kg; 178.5  4.8 cm) usually trains on a synthetic pitch, while Team B (n=7; 18.7  0.7 ys; 71.7  6.7 Kg; 178.3  5.7 cm) usually trains on natural grass. All the players performed two identical RSA tests, respectively on synthetic (Synt) turf (Football Green 57 SL, Limonta Sport, Italy) and natural grass (Nat). The protocol consisted of 6x40 m shuttle run sprints at maximal speed with 20 s of passive recovery1. In each sprint, the players started from a line, reached another line 20 m apart, touched it with a foot, and came back. Best time of a single trial (TBEST), mean time of the 6 sprints (TMEAN) and percent decrement (Decr%) = ([TMEAN/TBEST]x100)–100)) were assessed. Paired Wilcoxon tests were used to compare mean values between Nat and Synt. Significance was set at p

The purpose of this study was to compare sprint test performance performed by football players of different ages and levels of competition. One hundred and forty six Portuguese players from different teams completed the test (seven maximal sprints interspersed with 25 s active recovery). A 6 (level of competition: 1(st) national division, 2(nd) national division, 1(st) regional division, sub 16, sub 14, sub 12) 7 (sprint trial: sprint 1, sprint 2, sprint 3, sprint 4, sprint 5, sprint 6, sprint 7) repeated measures ANOVA was carried out on subjects sprint times. The main effect of level of competition was statistically significant, F(5, 140) = 106.28, p0.001. Subjects from 1(st) national division were significantly faster than subjects from 2(nd) national division; subjects from 1(st) regional division obtained similar performances when compared to sub 16 and sub 14 level; subjects from sub 12 level were the slowest. The main effect of sprint trial was also statistically significant, F (6, 840) = 7.37, p0.001. Mean sprint times from the first trial were significantly slower than mean sprint times from the second, third and fourth trial. Results from the fifth, sixth and seventh trials were slower, denoting a decrement in performance. The two main effects were qualified by a significant level of competition x sprint trial interaction, F (30, 840) = 9.47 p0.001, identifying markedly different performance profiles. Coaches should be aware that normative data regarding this test can play a very important role if used frequently and consistently during the whole season. Key PointsGroups of different ages (Sub 16, Sub 14 and Sub 12) and groups of different training quality (1(st) and 2(nd) national divisions and 1(st) regional division) were clearly discriminated by sprint test performances.Professional players exhibited higher performances in sprint test.Fatigue effects were the strongest between 5th to the 7th sprint.

Background This study determined the effect of repeated sprint training in hypoxia (RSH) in female athletes. Methods Thirty-two college female athletes performed repeated cycling sprints of two sets of 10 × 7-s sprints with a 30-s rest between sprints twice per week for 4 weeks under either normoxic conditions (RSN group; FiO2, 20.9%; n = 16) or hypoxic conditions (RSH group; FiO2, 14.5%; n = 16). The repeated sprint ability (10 × 7-s sprints) and maximal oxygen uptake (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \dot{\text{V}}{\text{O}}_{2\hbox{max} } $$\end{document}V˙O2max) were determined before and after the training period. Results After training, when compared to pre-values, the mean power output was higher in all sprints during the repeated sprint test in the RSH group but only for the second half of the sprints in the RSN group (P ≤ 0.05). The percentage increases in peak and mean power output between before and after the training period were significantly greater in the RSH group than in the RSN group (peak power output, 5.0 ± 0.7% vs. 1.5 ± 0.9%, respectively; mean power output, 9.7 ± 0.9% vs. 6.0 ± 0.8%, respectively; P

Female participation in regular sport activities has increased in recent years, yet their representation in the sports and exercise science literature remains low. Therefore, an understanding of the effects different phases of the menstrual cycle (MC) have on exercise responses is important due to the practical and theoretical implications. The aim of this study was to compare performance, physiological and perceptual differences when performing a running repeated sprint ability (RSA) during the early-follicular (EF), and mid-luteal (ML) sub-phases of the MC. Six healthy, physically active female participants (age: 25.67 ± 2.49 years; height: 1.66 ± 0.08 m; body mass: 69.8 ± 19.3 kg; V̇O2peak: 46.00 ± 6.76 ml·kg¹·min⁻¹) took part in this study. After the initial health screening, the participants completed two familiarisation and four intervention sessions (twice during each MC sub-phase). The RSA protocol consisted of five ‘all-out’ sprints of six seconds on a non-motorised treadmill with 24 seconds of active recovery (walking) between the sprints. Results indicated no significant differences between MC sub-phases in mean (p = 0.998, d = 0.00) and peak power output (p = 0.14, d = 0.16), distance (p = 0.59, d = 0.07), pre-exercise (p = 0.78, d = 0.41) and post-exercise lactate (p = 0.58, d = 0.24), oxygen uptake (p = 0.10, d = 0.30), respiratory exchange ratio (p = 0.47, d = 0.13), ventilation (p = 0.42, d = 0.12), heart rate (p = 0.49, d = 0.17). However, significant differences were found in peak acceleration (EF: 4.65 ± 0.84 m·s⁻², ML: 5.05 ± 1.14 m·s⁻²) (p = 0.02, d = 0.40) and rating of perceived exertion (RPE) (EF: 13.42 ± 2.15, ML: 12.60 ± 2.26) (p < 0.001, d = 0.37). In conclusion, MC phases do not appear to influence most of the chosen RSA performance indicators. However, due to the low sample size and statistical power, further studies are required to better investigate the effects of the MC on RSA.