Expression of BNDF Through Stretching as a Recovery Mechanism in Subjects With Overtraining

Introduction. The phenomena of biological adaptation and overtraining are closely related terms, that is why in sport it is possible to identify two types of overtraining. The first of these is known as short-term overtraining, which is required as a state of peripheral fatigue induced by repeated sessions of physical activity in short periods of time that are related to mechanisms of metabolic type (e.g. low levels of glycogen), is considered desirable and normal, by allowing mechanisms of adaptation to be activated depending on the nature and administration of the loads, which allow reaching higher yield quotas. The second, long-term overtraining, is characterized by a series of signs and symptoms of exhaustion and persistent fatigue that take place at the level of the central nervous system and that are produced by the imbalance between demanding physical work and recovery periods.

This type of condition is also known as, general syndrome of overtraining (GSO), unexplained low performance syndrome, staleness or burnout, which is propitiated by the need to achieve maximum physical performance and the performance of physical activities in a uncontrolled that cause an interruption to the processes of biological recovery that attenuate the obtaining of the physical form wished, reason why the sportsman experiences a decrease of the physical and mental performance, manifested in a clinical picture that reflects muscular inflammation, headache, elevation sudden blood pressure, loss of functional capacity, alterations of the central nervous system (CNS), metabolic, endocrine and immune systems. The neurotrophic factor derived from the brain (BDNF) influences different types of neurons in the CNS, promoting their differentiation, growth, survival, and neuroprotection by activating the mechanisms of synaptic plasticity.

BDNF decreases when performing specific physical exercises with intensities under the interval (mixed) and high-intensity method; as those who are employed in competitive cycles. For its part, stretching is commonly used as a method of physical rehabilitation in patients with musculoskeletal injuries of various origins. Its effect reflects the restoration of motor control by interacting with the intervention and order centers that are located in different parts of the CNS that are associated with the modulation of the discharge of the motor neurons involved in the activation of the muscle spindle, which allow the reflex for the execution of the movement and the control of postures. The information regarding the relationship with the GSO, the stretching and the expression of BDNF in the regenerative capacity in those over-trained subjects and their compensatory mechanisms during the different cycles of physical exercise, is null, making necessary the investigation of the effects that can produce in the decrease of factors that indicate GSO and, consequently, build support systems for the athlete with the purpose of returning it to a level of adequate physical performance.

Problem Statement. The training cycles are configured with the purpose of achieving a greater adaptation to the physical activity that is performed. However, those closest to the competition have more intensity and physical demands. However, the achievement of maximum performance and the GSO are phenomena deeply related to the adaptability of the organism. The strategies commonly used to recover an athlete with GSO, are directed to the care of diet and rest, however, do not make clear by what methods and means it is possible to perform a restoration of regenerative processes and muscle contraction to decrease of chronic fatigue and in turn the maintenance of physical performance achieved in previous cycles.

Research question. What are the effects of a stretching training program on BDNF expression and its relationship with biochemical and physiological markers that indicate GSO?