A single set of low intensity resistance exercise immediately following high intensity resistance exercise stimulates growth hormone secretion in men.

Aim. The purpose of the present study was to examine the effects of an additional set immediately following high intensity resistance exercise on growth hormone (GH) response. Methods. Subjects (n=8) performed 4 resistance exercise protocols (bilateral knee extension exercise) on separate days. The protocols were categorized into 2 types of protocol, namely Strength-up type (S-type) and Combination type (Combi-type). The S-type was resistance exercise which consisted of 5 sets at 90% of 1 repetition maximum (RM) with 3-min rest periods between sets, whereas the Combi-type is a training protocol which adds an additional set (either 50% of 1 RM [C50-type], 70% of 1 RM [C70-type] or 90% of 1 RM [C90-type]) to the S-type. Serum GH concentration and blood lactate concentration were determined pre-exercise and at 0-60 min postexercise. Relative changes in thigh girth and maximal unilateral isometric strength were determined pre-exercise and immediately postexercise. Results. The increasing values of GH concentration (ΔGH) in the S-type was the lowest of all protocols. On the other hand, ΔGH in the C50-type showed a significantly (p<0.05) higher increase than in the S-type and C90-type, and a relatively higher increase than in the C70-type. Conclusion. These results suggests that a high intensity, low volume training protocol to induce neural adaptation resulted in little GH response, but GH secretion was increased by performing a single set of low intensity resistance exercise at the end of a series of high intensity resistance sets.