Q: I’ve been bodybuilding for four years and I’m still not sure how fast or slow I should perform my repetitions. I often read that the reps should be slow, controlled and steady, only to turn the page to find another pro who says the reps should be fast and explosive. Who’s right, who’s wrong, and why?
A: Both are right. The speed, smoothness, consistency and control of reps vary according to the exercise, its purpose, the bodypart and the ordinal position of the set in your workout.
THE EXERCISE
Repetition speed will vary, depending upon whether the exercise is performed with cables, free weights or a machine. Since resistance with cables is consistent over the entire range of motion, the most effective use of cables is by means of slower repetitions, with a pace that is consistent through both the contraction and extension phases.
With free weights, the moment of force, or resistance, varies through the arc of the movement: At some points, the weight feels heavier than at others, just the opposite of the sensation associated with cables. You have to apply more power at those higher resistance points than at others, which means you have to accelerate or decelerate your repetition. Free weights are thus more effectively employed by repetitions that are controlled but slightly more explosive.