Bodybuilders have traditionally lifted with a submaximal lifting velocity, but new research is showing faster lifting may be better for muscle growth. Researchers examined the effects of maximum and submaximal lifting velocities after a muscular hypertrophy-type resistance-exercise protocol on testosterone, human growth hormone (HGH), and cortisol concentrations. Eleven males performed a control and three resistance-exercise protocols (four sets of squats and four sets of leg-press exercises, eight reps/set, 10-rep maximum load).

The first protocol was performed at maximum velocity; the second at 70% of maximal velocity with equal training volume; and the third at 70% of maximal velocity with a 10.6% higher training volume than the  maximum velocity group.

At the end of the study, testosterone and HGH increased after all exercise protocols. Cortisol concentrations gradually decreased in 70% submaximal and 70% submaximal with higher training volume, but remained relatively constant in the maximal velocity protocol. HGH was higher in submaximal lifting versus maximal lifting velocity while cortisol was higher in maximal lifting velocity versus the other groups.

In conclusion, maximal velocity, explosive, executed resistance exercise increases testosterone and HGH and generates a greater biological stress, as evident by a higher cortisol concentration. A protocol, however, performed at submaximal movement velocity combined with greater training volume stimulates HGH response to a greater degree with no effect on cortisol.

So the takeaway message is that in the off-season, incorporating more explosive-type exercise may be beneficial, but for contest preparation you may want to switch to a submaximal lifting velocity, which stimulates greater HGH responses with no increases in cortisol.- FLEX