Effect of Eccentric and Concentric Exercise on Plasma Nitric Compounds in Healthy Men

During all physical activities, including those of competitive sport different forms of muscular contractions are encountered. In some exercises concentric contractions dominate while in others there is a predominance of eccentric work. During eccentric contractions, mechanical changes in the sarcomers and sarcolemma, cause significant damage to the entire muscle cell. This phenomenon is manifested by the outflow of cell proteins, including enzymes and other metabolites. The consequences include muscle soreness, local tenderness, decreased range of motion and decreased strength. The main objective of this work was the observation of exercise, post exercise and recovery plasma changes of uric acid, urea and ammonia in men subjected to a progressive endurance exercise protocol performed with the predominance of concentric and eccentric muscular work. The conducted research allows to state that plasma concentration of uric acid and urea changed linearly to the increased work intensity in both concentric and eccentric exercise protocols, yet this was not true for ammonia and lactate concentration which increased exponentially. The greatest changes in plasma concentration of uric acid and urea occurred during the 24 hour recovery period, especially after eccentric muscle contractions. This confirms significantly greater muscle disruption following eccentric work. It can be concluded that the evaluation of plasma urea and uric acid concentration during exercise and recovery is not agood marker of exercise intensity, while plasma ammonia dynamics may serve this purpose well.