Abstract
Forearm blood flow in three male and one female subjects were determined with a mercury-in-rubber strain gauge venous occlusion plethysmography before, during and after rhythmic hand-grip exercise. The hand-grip exercise was performed on a hand-ergometer with the load of 5, 10, 20 and 30% of maximal voluntary contraction (MVC) of each subject, at the rate of 60 contractions/min as timed with a metronome.
The following results were obtained;
1) The forearm blood flow during rhythmic exercise at the tension of 5% MVC increased as soon as the exercise started and reached a steady state in apporoximately 1 min.
2) The forearm blood flow during rhythmic exercise at the tension of 10% MVC did not reach a steady level during 3 min exercise.
3) The forearm blood flow during rhythmic exercise at tensions of 20 and 30% MVC were increased steadily throughout the hand-grip exercise.
4) The forearm blood flow determined immediately before stopping the exercise and immediately after exercise at tensions of 5 and 10% MVC were apporoximately the same.
5) The blood flow in the forearm determined immediately before stopping the rhythmic exercise at tensions of 20 and 30% MVC were lower than the blood flow immediately after exercise.
6) From these results, it was concluded that the blood flow requirement of muscles during the rhythmic hand-grip exercise at tensions up to 10% MVC can adequately be supplied. Therefore, the rhythmic exercise at tensions up to 10% MVC can keep up for a very long time without fatigue.
