In order to lift a weight, muscular force must exceed the downward force of a load. The opposite occurs when you lower a weight – motor units are turned off until the downward force of the load is greater than the muscular force acting upon it. With less motor units active, greater tension and more damage occurs to the remaining muscle fibers, which prompts hypertrophy but may cause soreness in the process.

Eccentric loading can be reduced and even eliminated with the use of elastic assistance (e.g., a reverse-band setup on the squat, bench press, or chin-up), sleds, medicine balls, partner assistance, and in some cases by dropping the bar if using bumper plates. A useful method for beginners to avoid muscle soreness involves introducing eccentrics in a progressive manner as demonstrated below:

Week 1 – 100% concentric, 0% eccentric
Week 2 – 100% concentric, 50% eccentric
Week 3 – 100% concentric, 100% eccentric (normal ratio)

For example, assume a beginner was to perform two sets of the seated cable pulldown exercise. During the first week, the trainee will pull the bar to their chest (the concentric action) while their partner returns the bar to the initial position (the eccentric action) for every repetition of both sets. During the second week, the trainee performs both the concentric and eccentric action for the first set only; the second set is conducted with partner assistance on the eccentric action. During the third week and on, the trainee now performs both the concentric and eccentric action for every repetition of both sets. Dr. Tudor Bompa, considered by many as the father of periodization, believes this strategy will help personal trainers retain new clients since it deters soreness.