The effect of changes in concentric-eccentric contraction time ratio on hormonal response to resistance exercise in trained men

Summary Objectives The aim of this study was to investigate the effect of changing concentric-eccentric contraction time ratio in a single session of resistance exercise on hormonal response in trained men. Methods In a double-blind cross section study design, ten young men (mean age: 26.3 ± 1.2 years, mean weight: 81.2 ± 4.25 kg, and mean height: 178 ± 6 cm) were selected and completed 4 resistance exercise sessions with 3 days’ between sessions interval. Protocols included, 1 second concentric and 1 second eccentric contraction; 3 second concentric and 3 second eccentric contraction; 4 second concentric and 2 seconds eccentric contraction; 2 seconds concentric and 4 seconds eccentric contraction. In each session subjects performed one of the four protocols. The exercise protocol was consisted of leg extension, bench press, hamstring curls and lat pull-down with three sets of eight repetitions and intensity of 0.65 of one repetition maximum. Rest times for sets and exercises were 1 and 2 minutes respectively. Blood samples were collected before and immediately after exercise. Results Increases in lactate were observed after all protocols. Serum levels of testosterone and growth hormone increased significantly in all, but 1 second concentric and 1 second eccentric contraction protocol, while level of serum cortisol did not change significantly in none of the protocols. Conclusions The result of this study showed that in a single session of RE, changes in concentric-eccentric contraction time ratio had no effect on hormonal response, however slower contractions produced greater hormonal response compare to normal protocol.