RESUMEN
The aim of the present study was to assess the effects of beta-alanine supplementation on muscle strength and thickness. Nineteen resistance-trained men (age: 27.3 ± 5.5 years; height: 178 ± 10 cm; body mass: 83.4 ± 9.7 kg; training experience: 5.9 ± 3.9 years) were allocated to one of the following groups: Beta-alanine (BA) (6.4 g/day of beta-alanine) or Placebo (PLA) (6.4 g/day of maltodextrin). Subjects completed 4 resistance training sessions per week for 8 weeks. The following assessments were performed before and after intervention periods: 1 repetition maximum (1RM) and 60%1RM tests in the bench press (60%1RMBENCH) and back squat (60%1RMSQUAT) exercises; muscle thickness assessment of biceps brachialis (MTBB), triceps brachialis (MTTB), and vastus lateralis (MTVL) by ultrasonography. No significant difference between groups was observed for the absolute increase (pre-post intervention) in the 1RMBENCH (mean difference = 0.8 kg; p = 0.679), 1RMSQUAT (mean difference = 0.1 kg; p = 0.992), MTBB (mean difference = 0.7 mm; p = 0.637), MTTB (mean difference = 1.4 mm; p = 0.282), MTVL (mean difference = 1.6 mm; p = 0.311), 60%1RMBENCH (mean difference = 0.5 repetitions; p = 0.670) and 60%1RMSQUAT (mean difference = 0.7 repetitions; p = 0.690). In conclusion, the 8-week training period induced significant strength and morphological responses. However, the addition of beta-alanine supplementation did not enhance these adaptive outcomes.
RESUMEN
Abstract The aim of the current study was to analyze players' interactions in serve and serve return situations and examine the way points were decided due to players' positions and surfaces. Fourteen ATP 1000 tournament matches were analyzed (7 on hard surface; 7 on clay surface). The type of surface did not affect the way points ended (χ²=9.26; p > 0.05) but did influence serve return vertical positioning (χ²=270.86; p < 0.001). The return positioning, both lateral (χ²=92.68; p < 0.001 on deuce side - χ² = 78.98; p < 0.001 on advantage side) and vertical (χ²=33.59; p < 0.001), and the type of serve (χ²=45.13; p < 0.001) affected the way points were decided. The results from the present study suggest that tennis players should use, or at least seek, strategies based on aggressiveness and consistency of the 1st serve and also indicate that in the 2nd serve return, players are more offensive, and that on hard surfaces, players stand a few steps inside the court to return the serve, differently from clay surfaces. It recommended that serve returns should combine aggression, by inside the court positioning, and accuracy.
Resumo O objetivo do presente estudo foi analisar as interações dos jogadores em situações de saque e retorno de saque e examinar como os pontos foram decididos em função do posicionamento em quadra e dos tipos de superfície. Quatorze partidas do torneio ATP 1000 foram analisadas (7 em superfície dura; 7 em superfície de saibro). O tipo de piso não influenciou a forma como os pontos são definidos (χ²=9,26; p > 0,05), mas apresentou efeito sobre o posicionamento vertical na devolução de saque (χ²=270,86; p < 0.001). O posicionamento na devolução de saque, tanto vertical como lateral (no lado de iguais χ² = 92,68; p < 0,001 e no lado da vantagem χ²=78,98; p < 0,001), e o tipo de saque (χ²=45,13; p < 0.001) afetaram a forma como os pontos foram definidos. Os resultados do presente estudo sugerem que os tenistas devem usar, ou pelo menos buscar, estratégias de jogo baseadas na agressividade e consistência do 1º saque. Os resultados também indicam que na devolução do 2º saque os jogadores são mais ofensivos, e que nas superfícies duras os jogadores ficam alguns passos dentro da quadra para devolver o saque, diferentemente das superfícies de saibro. Recomenda-se que devoluções de saque combinem agressividade, por posicionamento dentro da quadra, e acurácia.
