Which type of contraction occurs when a muscle lengthens while producing force?

Eccentric contraction occurs when a muscle lengthens while producing force. This type of contraction is crucial during various activities such as lowering weights or descending stairs, where the muscle must control the movement against gravity or resistance. During an eccentric contraction, the muscle fibers generate tension but allow the muscle to elongate gradually, which helps to modulate the force being applied and absorb impact. This action is essential for maintaining joint stability and preventing injuries, as it helps manage the stresses placed on muscles and connective tissues. Eccentric contractions also play a significant role in muscle growth and rehabilitation, as they can lead to greater muscle fiber recruitment and adaptation.