Efficacy of the Most Commonly Used Physiotherapeutic Treatments for Acute Lower Limb Fatigue in Athletes

The etiology of injury in sport is multifactorial, generated by both intrinsic and extrinsic factors. There is evidence that supports that the management and handling of loads is the factor that generates the greatest risk of injury and that not respecting the load-recovery balance can lead to an accumulation of fatigue resulting in poor training adaptation which leads to increased risk of injury. From a physiological approach, fatigue is defined as a functional failure of the organism which, due to excessive energy expenditure and depletion of substrates necessary for energy production, leads to a decrease in performance.

Acute fatigue is the inability to generate a required or expected level of exercise force or intensity, whether or not preceded by previous exercise. Acute fatigue is an important risk factor in overuse injuries. It is multifactorial in nature and its mechanisms of formation are imprecise. This type of fatigue can affect both the peripheral level, generating neuromuscular or peripheral fatigue, and the central level, generating central fatigue. Peripheral or neuromuscular fatigue is the result of altered musculoskeletal homeostasis due to a limitation or failure of one or more motor unit processes, producing a dysfunction in the contraction process. Central fatigue is an involuntary failure in brain function or nerve impulse conduction, resulting in impaired transmission from the central nervous system (CNS) and impaired motor axon recruitment. One of the main factors associated with central fatigue is the alteration of synthesis and activity of some neurotransmitters.

Elite athletes push their training to the limit in order to maximize their performance. This generates muscle damage that results in a breakdown of structural proteins of muscle fibers and connective tissues, causing tissue inflammation, Delayed Onset Muscle Soreness (DOMS) and an increase in perceived fatigue. To maximize an athlete's ability to perform, it is not only the training that must be addressed, but also the balance between training and recovery. This prevents maladaptation to physiological and psychological stresses induced by the load. Therefore, it is important for the athlete to optimize the recovery period to reduce the risk of injury.

The purpose of this research is to demonstrate the efficacy of various physiotherapeutic protocols, analyzing the degree of effectiveness in each of these for recovery from acute fatigue in athletes.