Eccentric muscle actions: Implications for injury prevention and rehabilitation

Many acute muscle strain injuries are thought to occur during the eccentric phase of sudden, forceful muscle actions. Repeated eccentric muscle actions during exercise are also thought to contribute to microscopic muscle and tendon damage, leading to chronic muscle strains, muscle rupture and tendinopathy. Conversely, eccentric training has been demonstrated to have a positive effect in the prevention of muscle damage and injury. The properties of eccentric muscle actions which lead to this protective effect remain to be elucidated but are thought to include cellular, mechanical and neural adaptations. This clinical commentary is an attempt to analyze the potential role that eccentric training may have in both the contribution to and prevention of muscle injury by exploring the effect of various parameters on muscle structure and function. Guidelines as to the appropriate design of eccentric training programmes are also provided.