I wrote this: Muscles experience soreness due to weight resistance, and not when the weight is lifted (Mense & Russel, 2008). For instance, muscle soreness is not experienced when curling a dumbbell upwards; however, lowering the dumbbell forces the dumbbell to be to be stretched as it resists gravity and as such causes a micro trauma and muscle soreness (Keil, 2012). This is to say that if only the positive phase of lifting was completed without any weight resistance on the way down, no muscle soreness would be experienced. The muscles perform three different types of contractions being concentric, eccentric and isometric (Chen et al, 2013). Concentric contractions occur for example when lifting a weight up to the face, like above mentioned. Eccentric contractions are experienced when bringing the weight down and are characterized by a lengthening in the muscle fibers and as such plays a role in muscle soreness (Cannone, 2009). An isometric contraction on the other hand occurs when one is holding an object in a fixed position. Eccentric contractions cause a lot of tension and allow one to lower much heavier weight that what one can lift. Additionally, skeletal muscle is resistant to lengthening by nature. Eccentric contractions when repeated as such induce muscle damage (Barratt & Pool, 2008). DOMS occurs when weight is lowered, therefore lengthening of the muscle, micro trauma to muscle fibers occur, the body removes dead muscle fiber tissues and regenerates to allow resistance to further stress. After the muscles experience soreness, they adapt rapidly to reduce the chances of further damage from the same exercise of heavy weight lifting. This is known as repeated-bout effect (Medical Society of Nova Scotia, 1992). This reduces soreness and swelling the next time heavy lifting or the same exercise is done. There is also reduced strength as well as reduced range of motion therefore much faster recovery. could you add more details thank you.