No doubt in the course of your exploration into bodybuilding you have encountered numerous pieces of advice or questions from fellow lifters wanting to advise on, or wanting advice on, repetition speed. To put those new to bodybuilding in the loop a little, a repetition is a single lift performed through a full range of motion, from beginning to full contraction, back to the beginning again. Different repetition methods give different results, and the tempo of a lift can have a very noticeable effect on the outcome – depending upon what your goals are.
In bodybuilding, it’s all about the muscle mass and not about how strong you are. It’s perfectly possible to build a lot of muscle mass without becoming a great deal stronger, and it’s also possible to get a lot stronger without building any more muscle mass. I’m assuming you want to increase muscle mass and strength increases are secondary, so I’ll advise you about repetition speed based upon this assumption.
Bodybuilding is all about exhausting the muscle fibers through repeated effort – repetitions. This encourages the muscle fibers to grow back bigger which both gives extra pull in future lifts (thus strength) and also builds up some endurance strength as non-fiber aspects of the muscles are increased in size such as the sarcoplasmic portion.
Bodybuilders always benefit best from slow, deliberate movements as opposed to explosive lifts. This means you should keep your lifting speed relatively slow, and especially slow on the negative proportion of the repetition. When you lift something (contract) you have far less strength during this phase than you do when lowering (relaxing) the muscle. This allows you to really exaggerate the negative portion of the exercise to really deeply fatigue more fibers.
When you lift slowly – particularly on the negative portion of reps – you will sometimes find you suffer from DOMS in the days proceeding, especially if you are new to training or haven’t trained in a while. This comes from the negative portion of the repetition, and is basically a swelling of the muscle fibers causing nerve pain. Although it can feel very sore, it does ease and no lasting damage is done, providing you haven’t pulled or torn a muscle.
Just to re-emphasize then: For muscle mass, slower repetitions are better than fast, and extra slow negatives are the best.