Abstract
Exercise results in an increase in metabolism and the favorable redistribution of blood flow to the active area, by locally attenuating the vasoconstriction caused by the global increase in muscle sympathetic nerve activity, a process known as “functional sympatholysis”. The recent recognition that passive leg stretching (PLS) negatively affect exercise endurance by reducing mechanical efficiency and increasing accumulation metabolism byproducts, instigates the question does PLS affect functional sympatholysis? PURPOSE: To evaluate the effect of PLS on exercise endurance and functional sympatholysis. METHODS: In 8 healthy subjects (25±3 yr) femoral artery blood flow (FBF) was measured during a time to exhaustion (85% of maximal work rate) of a dynamic knee extension (KE) exercise. The measurement was repeated during the same exercise executed immediately after 5 min of passive leg stretching (KE+PLS). RESULTS: Time to limit during the KE was (19±3 min), and significantly decreased during KE+PLS (14±3; p<0.01). Steady-state FBF recorded during the 4th minute of KE was (5136±733 ml/min), and significantly decreased during the 4th minute of KE+PLS (3798±441 ml/min; p<0.01). CONCLUSIONS: These data reveal that 5 minutes of passive leg stretching does result in a extensive reduction ~26% in femoral blood flow. Interestingly, the time to limit was decreased by the same extend, implicating a possible association between the reduction of functional sympatholysis and the decrease of endurance performance. This PLS-induced reduction in oxygen delivery to the exercising skeletal muscle was likely determined by mechanical, neuromuscular, and biochemical factors, but other studies are needed to extend these preliminary results.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call