Exercise twice-a-day potentiates markers of mitochondrial biogenesis in men.

Endurance exercise begun with reduced muscle glycogen stores seems to potentiate skeletal muscle protein abundance and gene expression. However, it is unknown whether this greater signaling responses is due to performing two exercise sessions in close proximity-as a first exercise session is necessary to reduce the muscle glycogen stores. In the present study, we manipulated the recovery duration between a first muscle glycogen-depleting exercise and a second exercise session, such that the second exercise session started with reduced muscle glycogen in both approaches but was performed either 2 or 15 hours after the first exercise session (so-called "twice-a-day" and "once-daily" approaches, respectively). We found that exercise twice-a-day increased the nuclear abundance of transcription factor EB (TFEB) and nuclear factor of activated T cells (NFAT) and potentiated the transcription of peroxisome proliferator-activated receptor-É£ coactivator 1-alpha (PGC-1α), peroxisome proliferator-activated receptor-alpha (PPARα), and peroxisome proliferator-activated receptor beta/delta (PPARß/δ) genes, in comparison with the once-daily exercise. These results suggest that part of the elevated molecular signaling reported with previous "train-low" approaches might be attributed to performing two exercise sessions in close proximity. The twice-a-day approach might be an effective strategy to induce adaptations related to mitochondrial biogenesis and fat oxidation.

Effect of caffeine ingestion on anaerobic capacity quantified by different methods.

We investigated whether caffeine ingestion before submaximal exercise bouts would affect supramaximal oxygen demand and maximal accumulated oxygen deficit (MAOD), and if caffeine-induced improvement on the anaerobic capacity (AC) could be detected by different methods. Nine men took part in several submaximal and supramaximal exercise bouts one hour after ingesting caffeine (5 mg·kg-1) or placebo. The AC was estimated by MAOD, alternative MAOD, critical power, and gross efficiency methods. Caffeine had no effect on exercise endurance during the supramaximal bout (caffeine: 131.3 ± 21.9 and placebo: 130.8 ± 20.8 s, P = 0.80). Caffeine ingestion before submaximal trials did not affect supramaximal oxygen demand and MAOD compared to placebo (7.88 ± 1.56 L and 65.80 ± 16.06 kJ vs. 7.89 ± 1.30 L and 62.85 ± 13.67 kJ, P = 0.99). Additionally, MAOD was similar between caffeine and placebo when supramaximal oxygen demand was estimated without caffeine effects during submaximal bouts (67.02 ± 16.36 and 62.85 ± 13.67 kJ, P = 0.41) or when estimated by alternative MAOD (56.61 ± 8.49 and 56.87 ± 9.76 kJ, P = 0.91). The AC estimated by gross efficiency was also similar between caffeine and placebo (21.80 ± 3.09 and 20.94 ± 2.67 kJ, P = 0.15), but was lower in caffeine when estimated by critical power method (16.2 ± 2.6 vs. 19.3 ± 3.5 kJ, P = 0.03). In conclusion, caffeine ingestion before submaximal bouts did not affect supramaximal oxygen demand and consequently MAOD. Otherwise, caffeine seems to have no clear positive effect on AC.

Relative age effect in fifa u17 emirates 2013 world cup: analysis of players who effectively participated in the matches / Efeito da idade relativa na copa do mundo fifa sub-17 emirates 2013: análise de jogadores que efetivamente participaram nos Jogos / Efecto de la edad relativa en la copa mundial de fútbol sub-17 emiratos 2013: análisis de los jugadores que participaron efectivamente en los partidos

The purpose of this study was to verify the date of birth is a decisive factor for the success of players selected by the coaches to participate in the FIFA U-17 World Cup Emirates 2013. The players' date of birth were classified into four quartiles of three months each (Q1 to Q4). In the qualifying round, 46.5% of the selected players born in Q1, while 12.5% in Q4. This significantly different distribution occurred until the semi-finals. However, in the final match, there were no significant differences between Q1 and Q4. A similar relative age effect also occurred when analyzed only players who actually participated to the matches. Interestingly, despite there was birth date effect on performance in all World Cup stages except in the final, other issues should take into consideration for a team became champion.

O objetivo deste estudo foi verificar se a data de nascimento é um fator decisivo para o sucesso de jogadores selecionados pelos treinadores para participar da Copa do Mundo Sub-17 Emirates 2013. As datas de nascimento dos jogadores foram classificadas em quatro quartis de três meses de cada (Q1 a Q4). Na qualificação, 46,5% dos jogadores selecionados nasceram em Q1, enquanto 12,5% em Q4. Esta distribuição significativamente diferente ocorreu até às semifinais. Entretanto, na final, não houve diferenças significativas entre Q1 e Q4. Um efeito similar da idade relativa também ocorreu quando analisados apenas os jogadores que efetivamente participaram das partidas. Curiosamente, apesar de haver efeito da data de nascimento sobre o desempenho em toda Copa do Mundo, exceto na final, outras questões devem levadas em consideração para uma equipe sagrar-se campeã.

La finalidad de este estudio fue verificar la fecha de nacimiento es un factor decisivo para el éxito de los jugadores seleccionados por los entrenadores para participar de la Copa Mundial sub-17 FIFA Emirados Árabes Unidos 2013. Fecha de nacimiento se clasificaron en cuatro cuartiles de tres meses (Q1 a Q4). En la qualificación, 46,5% de los seleccionados nacieron en Q1, mientras 12,5% en Q4. Esta distribución diferente ocurrió hasta las semifinales. Sin embargo, en la final, no hubo diferencias entre Q1 y Q4. Un efecto similar también ocurrió cuando se analizaron sólo los jugadores que efectivamente hugaron. Curiosamente, mismo con efecto de la fecha de nacimiento en toda la Copa Mundial, excepto la final, otros temas deben tener en cuenta para un equipo hacerse campeón.