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Purpose: Morning priming exercise and caffeine intake have been previously suggested as an effective strategy to increase within-day performance and readiness. However, the concurrent effect of both strategies is unknown. The present research aimed to map the within-day time course of recovery and performance of countermovement jump (CMJ) outcomes, kinetics, and strategy and readiness after priming alone and in combination with caffeine. Methods: Eleven participants performed a control, a priming exercise (Priming) and a priming with concurrent caffeine intake (PrimingCaf) in a double-blind randomized, crossover design. CMJ metrics were assessed before, post, and 2 h, 4 h, and 6 h after each condition while readiness was assessed at 6 h. Results: Perceived physical, mental performance capability and activation balance were higher at 6 h after Priming and PrimingCaf conditions. Immediate reductions in jump height (5.45 to 6.25%; p <.046), concentric peak velocity (2.40 to 2.59%; p <.041) and reactive strength index-modified (RSImod) (9.06 to 9.23% p <.051) after Priming and PrimingCaf were observed, being recovered at 2 h (p >.99). Concentric impulse was restored in PrimingCaf (p >.754; d = −0.03 to-0.08) despite lower concentric mean force/BM (p <.662; d = −0.18 to −0.26) as concentric duration was increased (p >.513; d = 0.15 to 0.21). Individual analysis revealed that some participants benefit from both strategies as they showed increases in jump height over the smallest worthwhile change while others did not. Conclusions: Psychological readiness was increased after both priming conditions at 6 h; however, it seems necessary to consider individual changes to achieve the positive effects of the priming or the priming in combination with caffeine on jumping outcomes. [ABSTRACT FROM AUTHOR]

Objective: Various nutritional strategies are adopted for athletes to maintain and to improve performance during the competition season. Betaine may enhance performance during a competitive season by increasing the testosterone to cortisol ratio and reducing systemic inflammation. The aim of this study was to investigate the effect of betaine supplementation on the bio-motor abilities in young professional soccer players. Methods: Twenty-nine young professional soccer players (age, 15.5±0.3 years) were matched by position and randomly assigned to one of two groups for 14 weeks: betaine (BG, 2 g/day; n=14) or placebo (PG n=15). Diet was standardized by a nutritionist, and measures of muscular power (countermovement jump: CMJ), change of direction: modified 5-0-5), acceleration (10 m sprint), sprint performance (30 m sprint time: SpT), muscular strength (leg press and bench press one repetition maximum: 1-RM), repeated sprint ability (running-based anaerobic sprint test: RAST), and aerobic capacity (30-15 intermittent fitness test) were assessed in the pre (P1), mid (P2) and post (P3) season over the course of 5 days. All subjects participated in one soccer match and five training sessions per week. Results: Significant (p < 0.05) group x time interactions were found for maximal oxygen uptake (VO2max), anaerobic peak power, and muscular strength favoring BG at P2 and P3 compared to P1. There were meaningful (p < 0.05) group x time interactions for CMJ, SpT, and peak power during the RAST that favored the BG. Conclusions: 14-week of betaine supplementation increased predicted 1-RM, VO2max, and repeated sprint ability performance in youth professional soccer players. Betaine supplementation seems to be a useful nutritional strategy to improve and to maintain performance during a competitive soccer season. [ABSTRACT FROM AUTHOR]

The aims of this study are (a) to describe the evolution of neuromuscular performance over an 18 year period within a Spanish elite reserve team; (b) to check if there were any relation between the playing position and sprint and jump performances and (c) to look into the alleged impact of this factor on the top playing level attained by the soccer players. We considered the physical tests (5 m and 15 m sprint times and countermovement jump (CMJ) height) made by 235 players enrolled in the reserve team of the Club from 1994 to 2012 and the highest competitive-level they achieved: Spanish first (n = 39) and second divisions (n = 36) and semi-professional (n = 160). Furthermore, the players were classified according to their playing positions. The main findings were a very-likely/most-likely lower neuromuscular performance (ES = 0.48–0.68, small to moderate) in the last six-season term (2006–2012) than in the first term (1994–2000); possibly/very-likely lower performances in sprinting and CMJ (ES = 0.22–0.55, small) by central defenders (CDs) and midfielders than by other playing positions; very-likely better performances in sprinting and jumping by first and second divisions central defenders than by semi-professional central defenders (ES = 0.90–1.02, moderate). Sprint and jump performances are not a relevant physical parameter to promote to the top level of soccer in Spain except for one in six of the playing positions: CDs. [ABSTRACT FROM PUBLISHER]

There is some evidence to suggest that ability to develop force in skeletal muscle can be improved for a short period following repeated maximal strength exercise. Some studies have suggested the phenomenon known as post-activation potentiation (PAP) to explain this immediate response to such exercise. However, little is known about the physical and temporal characteristics of the changes in muscle function due to PAP when induced using whole-body maximal strength exercise. The purpose of this study was to establish the physical and temporal characteristics of PAP of muscle function in elite male athletes following maximum strength and power exercise. Fifteen participants performed one of repeated maximal strength exercise or maximal power exercise or a control protocol on separate occasions. Changes in maximum isometric voluntary force (iMF), maximum isometric rate of force development (iRFD) and maximum vertical counter-movement jump (CMJ) were assessed. Results suggest that post-activation potentiation of iRFD occurs but is preceded by an initial suppression of force development capability following repeated maximal strength exercise. Following repeated maximal power exercise, however, post-activation potentiation of iRFD occurs immediately but is not seen over as long a period as that observed following maximal strength exercise. These results suggest that post-activation potentiation does bring about increased force development capability following intense exercise and that the temporal profile of the post-activation potentiation changes with intensity of the exercise used to induce it. [ABSTRACT FROM AUTHOR]