There always appears to be disagreement and arguments amongst bodybuilders and the like over if you should do slow controlled movement to really contract a muscle you’re trying to grow or instead say do more explosive concentric reps to get some added power or performance benefits from your training. Would doing these faster concentric make muscle sise gains suboptimal compared to a more controlled technique? We go all the way back to 1993 today to look at what research tells us. John always reviews the full-text of every article, but you may view the free abstract by clicking here: http://journals.lww.com/nsca-jscr/Abstract/1993/08000/The_Effect_of_Voluntary_Effort_to_Influence_Speed.9.aspx .