Purpose: The aim of the present study was to investigate the influence of futsal match-related fatigue on running performance, neuromuscular variables, and finishing kick speed and accuracy.Methods: Ten professional futsal players participated in the study (age: 22.2 ± 2.5 years) and initially performed an incremental protocol to determine maximum oxygen uptake (trueV˙O2max: 50.6 ± 4.9 mL.kg−1.min−1). Next, simulated games were performed, in four periods of 10 min during which heart rate and blood lactate concentration were monitored. The entire games were video recorded for subsequent automatic tracking. Before and immediately after the simulated game, neuromuscular function was measured by maximal isometric force of knee extension, voluntary activation using twitch interpolation technique, and electromyographic activity. Before, at half time, and immediately after the simulated game, the athletes also performed a set of finishing kicks for ball speed and accuracy measurements.Results: Total distance covered (1st half: 1986.6 ± 74.4 m; 2nd half: 1856.0 ± 129.7 m, P = 0.00) and distance covered per minute (1st half: 103.2 ± 4.4 m.min−1; 2nd half: 96.4 ± 7.5 m.min−1, P = 0.00) demonstrated significant declines during the simulated game, as well as maximal isometric force of knee extension (Before: 840.2 ± 66.2 N; After: 751.6 ± 114.3 N, P = 0.04) and voluntary activation (Before: 85.9 ± 7.5%; After: 74.1 ± 12.3%, P = 0.04), however ball speed and accuracy during the finishing kicks were not significantly affected.Conclusion: Therefore, we conclude that despite the decline in running performance and neuromuscular variables presenting an important manifestation of central fatigue, this condition apparently does not affect the speed and accuracy of finishing kicks.

The aim of the present study was to investigate the effects of acute administration of taurine overload on time to exhaustion (TTE) of high-intensity running performance and alternative maximal accumulated oxygen deficit (MAODALT). The study design was a randomized, placebo-controlled, crossover design. Seventeen healthy male volunteers (age: 25 ± 6 years; maximal oxygen uptake: 50.5 ± 7.6 mL·kg(-1)·min(-1)) performed an incremental treadmill-running test until voluntary exhaustion to determine maximal oxygen uptake and exercise intensity at maximal oxygen uptake. Subsequently, participants completed randomly 2 bouts of supramaximal treadmill-running at 110% exercise intensity at maximal oxygen uptake until exhaustion (placebo (6 g dextrose) or taurine (6 g) supplementation), separated by 1 week. MAODALT was determined using a single supramaximal effort by summating the contribution of the phosphagen and glycolytic pathways. When comparing the results of the supramaximal trials (i.e., placebo and taurine conditions) no differences were observed for high-intensity running TTE (237.70 ± 66.00 and 277.30 ± 40.64 s; p = 0.44) and MAODALT (55.77 ± 8.22 and 55.06 ± 7.89 mL·kg(-1); p = 0.61), which seem to indicate trivial and unclear differences using the magnitude-based inferences approach, respectively. In conclusion, acute 6 g taurine supplementation before exercise did not substantially improve high-intensity running performance and showed an unclear effect on MAODALT.

The aims of the present study were to verify the contributions of the energy systems during repeated sprints with a short recovery time and the associations of the time- and power-performance of repeated sprints with energetic contributions and aerobic and anaerobic variables. 13 healthy men performed the running-based anaerobic sprint test (RAST) followed by an incremental protocol for lactate minimum intensity determination. During the RAST, the net energy system was estimated using the oxygen consumption and the blood lactate responses. The relative contributions of oxidative phosphorylation, glycolytic, and phosphagen pathways were 38, 34, and 28%, respectively. The contribution of the oxidative pathway increased significantly during RAST especially from the third sprint, at the same time that power- and time-performances decreases significantly. The phosphagen pathway was associated with power-performance (peak power=432±107 W, r=0.65; mean power=325±80 W, r=0.65; minimum power=241±77 W, r=0.57; force impulse=1 846±478 N·s, r=0.74; <0.05). The time-performance (total time=37.9±2.5 s; best time=5.7±0.4 s; mean time=6.3±0.4 s; worst time=7.0±0.6 s) was significantly correlated with the oxidative phosphorylation pathway (0.57+0.65; <0.05) and glycolytic pathway (0.57+<+r>0.58; <0.05). The oxidative pathway appears to play an important role in better recovery between sprints, and the continued use of the glycolytic metabolic pathway seems to decrease sprint performances. Finally, the phosphagen pathway was linked to power production/maintenance.

The purpose of the study was to investigate the sensitivity of an alternative maximal accumulated oxygen deficit (MAOD) method to discriminate the "anaerobic" capacity while comparing: least trained (LT) participants (n = 12), moderately trained (MT) participants (n = 12), endurance trained (ET) participants (n = 16), and rugby (RG) players (n = 11). Participants underwent a graded exercise test on a treadmill and a supramaximal effort for assessing MAOD. MAOD was calculated as the sum of oxygen equivalents from the phosphagen and glycolytic metabolic pathways. MAOD was significantly higher (P < 0.05) in RG (64.4 ± 12.1 mL · kg) than in ET (56.8 ± 5.4 mL · kg; effect size [ES] = 0.77; +13.5%), MT (53.8 ± 5.3 mL · kg; ES = 1.08; +19.8%), and LT (49.9 ± 4.5 mL · kg; ES = 1.50; +36.4%). In addition, the magnitude-based inference analysis revealed that MAOD was likely (LT vs. MT), very likely (MT vs. RG, and ET vs. RG) and most likely (LT vs. ET, and LT vs. RG) different between all groups, except for MT and ET, which presented an unclear difference. In conclusion, MAOD was sensitive enough to distinguish the "anaerobic" capacity in individuals with different training status, especially for RG players compared with LT participants and MT participants.

Zagatto, AM, Ardigò, LP, Barbieri, FA, Milioni, F, Dello Iacono, A, Camargo, BHF, and Padulo, J. Performance and metabolic demand of a new repeated-sprint ability test in basketball players: does the number of changes of direction matter? J Strength Cond Res 31(9): 2438-2446, 2017-This study compared 2 repeated-sprint ability (RSA) tests in basketball players. Both tests included 10 × 30-m sprints, with the difference that the previously validated test (RSA2COD) featured 2 changes of direction (COD) per sprint, whereas the experimental test (RSA5COD) featured 5 CODs per sprint. Test performances and metabolic demands were specifically assessed in 20 basketball players. First, RSA5COD test-retest reliability was investigated. Then, RSA2COD, RSA5COD sprint times, peak speeds, oxygen uptake (V[Combining Dot Above]O2) and posttest blood lactate concentration [La] were measured. The RSA5COD results showed to be reliable. RSA2COD performance resulted better than the RSA5COD version (p < 0.01), with shorter sprint times and higher peak speeds. Over sprints, the tests did not differ from each other in terms of V[Combining Dot Above]O2 (p > 0.05). Over whole bout, the RSA2COD was more demanding than the RSA5COD, considering overall metabolic power requirement (i.e., VO2-driven + [La]-driven components). Given that RSA5COD (a) mimics real game-play as sprint distance and action change frequency/direction and (b) has the same metabolic expenditure per task completion as metabolic cost, RSA5COD is a valuable option for players and coaches for training basketball-specific agility and assessing bioenergetic demands.