Effects of ramp and ballistic contractions on post-exercise hyperemia in human triceps surae / 体力科学

ABSTRACT

This study was designed to compare post-exercise hyperemia between ramp and ballistic contractions in human triceps surae. Subject was asked to extend ankle joint in range of 20 degrees for 1 sec and with maximum effort against loads of 10, 20, 30 or 40% of maximum voluntary contraction (MVC) in ankle extensors. Amount of post-exercise hyperemia was calculated from changes in calf girth recorded by using two strands mercury-in-rubber gauge.<BR>1) Calf girth after contractions transiently decreased below precontraction level and increased gradually until its peak value, over precontraction level, in about 8 sec. Calf girth recovered to resting level for about 30 sec.<BR>2) After ramp contractions, amount of decrease of calf volume increased in order to loads of 10, 20, 30 and 40% MVC, but was not so after ballistic contractions. Amount of its increase, excess precontraction level, depended on loads in both conditions. These values were below 1.0m<I>l</I>/100 m<I>l</I> tissue.<BR>3) Amount of decrease of calf volume after ramp contraction was larger than that of ballistic contraction, but amount of its increase was inverse.<BR>4) There was significant coefficient between calf volume increase after contraction and maximum inflow rate (m<I>l</I>/min/100 m<I>l</I> tissue) calculated from the maximum gradient in rising phase of calf girth (r=0.5508, p<0.001) .<BR>From these results, it is suggested that“milking action”in muscle generate with ramp contraction, and that disturbance of pulsatile inflow to muscle and chemical and neuronal regulations to generate post-exercise hyperemia pronouncely act by ballistic contraction.