Resistance exercise, muscle damage and inflammatory response “what doesn’t kill you makes you stronger”

Abstract

Exercises involving eccentric actions, mainly in untrained subjects, induce muscular damage to a higher extent than concentric actions. This damage arises from muscle injury and may cause rupture and inflammation of muscle, connective or nervous tissues. These changes in muscle morphology may occur as a direct consequence of exercise-induced mechanical stress or later due to activation of calcium-sensitive degradation pathways and inflammatory response. Later, this damage is exacerbated by the inflammatory response in the days after the exercise. However, an attenuated inflammatory response to a repeated bout reflects in an adaptation to avoid the proliferation of the mechanical disruption of myofibrils. Thus, muscle damage decreases when a person performs the same exercise consistently. This phenomenon is commonly known as the repeated bout effect or protective effect.