Having a strong body involves having strong muscles and having strong muscles is a major plus in basically every sport or active activity that you can think of. In order to enhance the strength of your body, you need to place your muscles under stress so that they learn to adapt and become stronger.
One of the most effective ways of doing this is resistance training. This can be broken down even further into two distinct types of exercises when it comes to resistance training.
Concentric exercises - This is the movement that occurs when the contraction shortens the muscles. For example, during a bicep curl the concentric movement occurs when the dumbbell is being lifted up towards your shoulder.
Eccentric exercises - This movement occurs when there is a negative contraction as it is lengthened whilst producing force. For example, during a bicep curl the eccentric movement occurs as the dumbbell is being lowered back down into the resting position.
Many people focus on the concentric movement of the exercise, which makes sense, because this is where you will enhance your basic movement. However by focusing your attention into slowing down the eccentric movement, you are going to increase the effectiveness of muscle strength enhancement.
So next time you are lifting weights, remember to slow the whole movement down and focus both on the lifting and the lowering with the movement so that you can gain the most from your resistance training!