The first number represents the Eccentric Phase, also known as the "negative" portion of the
lift. This is the point where the weight is being lowered and there is a muscular tension while the muscle is being stretched. Hypertrophy training
programs typically emphasize a slow and controlled eccentric movement.
This phase is very taxing on the muscle fibers and is the reason why the
majority of muscle fiber breakdown - a positive thing when it comes to muscle
The second number represents the Hold at bottom of
movement - This phase being the end of the eccentric range of motion. Typically
you will either hold this position for a second, or immediately lift the
weight and begin the next phase. Whether you hold this position or go
immediately into the next phase will depend on whether there is tension
on the muscle at this point for the specific muscle group you are
The third number, also known as the Concentric phase -
This phase is also referred to as the "positive" portion of the lift.
During this phase, the muscle is contracting while being under load and this
movement is normally faster than the lowering phase. This step will
take the weight back to the starting position of the exercise.