Hypertrophy, muscular atrophy and eccentric contraction

When your body has adapted to an activity, it won't produce enough stress to stimulate new muscle growth. 

• Hypertrophy, an increase in muscular size through exercise, is possible by exposing your cells to higher workloads than they are used to.
• If you don't continuously expose your muscles to some resistance, they will shrink, known as muscular atrophy.
• Exposing the muscle to a high degree of tension while the muscle is lengthening is called an eccentric contraction.

When you expose your body to stress, such as pushing something heavy, your muscles experience microscopic damage. In response, the injured cells release inflammatory molecules called cytokines that activate the immune system to repair the injury. This is when muscle-building happens.

The g...