Monitoring strength training: neuromuscular and hormonal profile

Purpose: This study investigated changes induced by a single heavy resistan ce training session on neuromuscular and endocrine systems in trained athle tes, using the same exercises for training and testing. Methods: Five diffe rent groups volunteered: track and field male sprinters (MS, N = 6), track and field female sprinters (FS, N = 6), body builders (BB, N = 6), and weig ht lifters performing low-repetition exercise (WLL, N = 4) and high-repetit ion exercise (WLH, N = 4). In training, the work performed during half and full squat exercise was monitored for mechanical power output as well as EM G analysis on leg extensor muscles of the subjects belonging to the MS, FS, and BE groups. Just before and immediately after the training session; ven ous blood samples were obtained for RIA determination of testosterone (T), cortisol (C), lutropin (LH), human prolactin (PRL), and follitropin (FSH) i n FS and MS. In the other three groups (BB, WLH, and WLL), the hormonal pro file was Limited to T and human growth hormone (hGH) only. Results: After t raining the power developed in full squat demonstrated a statistically sign ificant decrease (P < 0.01) in MS and no changes in FS. The EMG activity re mained constant during the training session. Consequently, the EMG/Power ra tio increased in both MS and FS, although only in MS a statistical signific ance was noted (P < 0.05). In MS immediately after the session the levels o f C, T, and LH were significantly lower (P < 0.05). No changes were found i n FS. la both groups and in BE significant negative correlation was found b etween changes in T level and EMG/Power ratio in half squat performance. Co nclusions: Ir is Likely that adequate T level may compensate the effect of fatigue in FT fibers by ensuring a better neuromuscular efficiency.