In your traditional exercise, like the bench press, there are three types of muscle contraction:
a.The concentric contraction is the one that we are all familiar with. This motion occurs when you contract a muscle to lift the weight up.
a.You may be familiar with isometric contraction, where no motion occurs. This motion occurs if you lean against your house and push against it as hard as you can. Your muscles contract, but no joint motion occurs.
a.An eccentric contraction occurs when a muscle is contracting and an external force is trying to lengthen the muscle.
On the bench press (and with almost all lifts), the concentric contraction occurs as you raise the weight, the eccentric occurs as you lower the weight, and the isometric occurs at the top and bottom of each rep as you pause to transition between up and down motions (or when you get stuck).
So, how is this helpful to know?
There is a strength hierarchy. The eccentric contraction should be the strongest, then the isometric, and then the concentric contraction.
Most people rush the eccentric (lowering) motion, which causes the strength gap from eccentric to concentric motions to narrow. In turn, this will cause a strength plateau. It’s your body’s way of protecting itself from injury. In addition, your connective tissues (tendons, fascia, etc…) develop the most during the eccentric motion, and the nervous system is challenged to adapt with slow eccentrics.
If you have plateaued, have a particular exercise that you just can’t get improve, or haven’t worked out in some time, try using ultra slow (10 second) eccentrics for the next six workouts.