madman
Super Moderator
Abstract: This study was aimed at investigating whether quercetin (Q) may improve the recovery of neuromuscular function and biochemical parameters in the 7 days following eccentric exercise-induced muscle damage (EEIMD). Sixteen men (25.9 ± 3.3 y) ingested Q (1000 mg/day) or placebo (PLA) for 14 days following a double-blind crossover study design. A neuromuscular (NM) test was performed pre-post, 24 h, 48 h, 72 h, 96 h and 7 days after an intense eccentric exercise. The force-velocity relationship of the elbow flexor muscles and their maximal voluntary isometric contraction (MVIC) were recorded simultaneously to the electromyographic signals (EMG). Pain, joint angle, arm circumference, plasma creatine kinase (CK), and lactate-dehydrogenase (LDH) were also assessed. The results showed that Q supplementation significantly attenuated the strength loss compared to PLA. During the recovery, force-velocity relationship and mean fibers conduction velocity (MFCV) persisted significantly less when participants consumed PLA rather than Q, especially at the highest angular velocities (p < 0.02). A greater increase in biomarkers of damage was also evident in PLA with respect to Q. Q supplementation for 14 days seems able to ameliorate the recovery of eccentric exercise-induced weakness, neuromuscular function impairment, and biochemical parameters increase probably due to its strong anti-inflammatory and antioxidant action.
1. Introduction
During eccentric exercise, skeletal muscle is exposed to stretch and overload which causes structural damage to myofibers and secondary inflammation resulting from leukocyte infiltration into the damaged tissues [1]. Signs and symptoms of eccentric exercise-induced muscle damage (EEIMD) often persist for several days after the conclusion of exercise and typically include muscle pain, localized swelling, temporary decrements in maximal force-generating capacity, altered joint kinematics, elevated levels of intramuscular enzymes (i.e., creatine kinase (CK) and lactate dehydrogenase (LDH)), elevations in markers of inflammation and various interleukins [2,3]. Although the specific mechanisms responsible for these signs and symptoms are not completely understood, inflammation and reactive oxygen species (ROS) are presumably among the primary causes.
4. Discussion
This study has shown that 14-day Q supplementation not only attenuates the magnitude of damage resulting from eccentric exercise but also ameliorates the time course of symptoms associated with the inflammatory response of the secondary damage and accelerates the recovery of neuromuscular function.
5. Conclusions
In conclusion, the results from the present study, besides extending previous evidence of the effectiveness of Q supplementation in mitigating the extent of muscle damage induced by eccentric exercise, provide new insights into the time course of symptoms associated with the recovery of neuromuscular function after EEIMD. Quercetin has the potential to represent a nutritional strategy to ameliorate skeletal muscle damage, not only for the impact on the redox process but also for factors acting at the CNS level.
1. Introduction
During eccentric exercise, skeletal muscle is exposed to stretch and overload which causes structural damage to myofibers and secondary inflammation resulting from leukocyte infiltration into the damaged tissues [1]. Signs and symptoms of eccentric exercise-induced muscle damage (EEIMD) often persist for several days after the conclusion of exercise and typically include muscle pain, localized swelling, temporary decrements in maximal force-generating capacity, altered joint kinematics, elevated levels of intramuscular enzymes (i.e., creatine kinase (CK) and lactate dehydrogenase (LDH)), elevations in markers of inflammation and various interleukins [2,3]. Although the specific mechanisms responsible for these signs and symptoms are not completely understood, inflammation and reactive oxygen species (ROS) are presumably among the primary causes.
4. Discussion
This study has shown that 14-day Q supplementation not only attenuates the magnitude of damage resulting from eccentric exercise but also ameliorates the time course of symptoms associated with the inflammatory response of the secondary damage and accelerates the recovery of neuromuscular function.
5. Conclusions
In conclusion, the results from the present study, besides extending previous evidence of the effectiveness of Q supplementation in mitigating the extent of muscle damage induced by eccentric exercise, provide new insights into the time course of symptoms associated with the recovery of neuromuscular function after EEIMD. Quercetin has the potential to represent a nutritional strategy to ameliorate skeletal muscle damage, not only for the impact on the redox process but also for factors acting at the CNS level.
