In-season strength and power changes in elite female volleyball players accompanying periodized strength and ballistic training
Eight males participated in this study to examine the effects of an essential amino acid supplement, Rebuild 1111, on cortisol secretions induced by resistance training. Subjects were randomly allocated to either branched chain amino acids (BCAA) orplacebo (P) groups. The protocol followed a double blind cross-over design whereby both groups participated in three weeks of supplementation followed by a week of resistance training with continued supplementation. Within this week, four resistance training sessions occurred, each of which comprised three sets of six to eight repetitions of leg press, leg curl, leg extension, chest press, military press, latissimus pulldown, dumbbell curl, and tricep pushdown, at 75 - 80% of IRM. This protocol was repeated, consuming the alternative treatment, following a five week period with no supplement or training. Blood was drawn at baseline, after three weeks of supplementation (day 2 1), two days of training (day 24), four days of training (day 27), and 48 hours after final training session (day 28). Serum was analyzed for cortisol (C), testosterone (T), and creatine kinase (CK). Subjects were allocated to either light (Group A) or heavy (Group B) due to the high correlation (r = 0.736 to 0.966) between mass and the measured variables, and theheterogeneous nature of these two subgroups. A repeated measures ANOVA with a significant level set at p<0.05, found no difference between BCAA and P for either group for any of the measured variables. Group A however had consistently lower serum C and CK, and higher T and testosterone:cortisol ratio with BCAA supplementation. Group B hormone response was inconsistent with training and supplementation. Group B CK was consistently lower with BCAA supplementation. Conclusions: There is some evidence that BCAA supplementation may reduce the catabolic stress response and cellular breakdown due to resistance training. Further study investigating the effect of varied dose and mass of subjects is required to elucidate these findings further. For statistical significance, larger sample size is needed.