Immediate effects of exercise on apparent limb mass and circumference.

Abstract

54 subjects were given a standardized elbow flexion exercise consisting of holding the arm flexed at 90 ° against the pull of a 20 lb. weight while in a recumbent position. Measurements were obtained on apparent weight of the arm and on upper arm and forearm circumferences during a period of 10 min. prior to exercise and 20 min. after exercise. The immediate post-exercise upper arm circumference was 1 percent greater than the resting level (t = 10.3) and the lower arm circumference was also 1 percent greater (t = 12.3). The circumferences gradually returned toward the pre-exercise resting level during the 20 min. of recovery period. However, they had not completely returned at this time. The upper arm circumferences lost only 65 percent of the increase. The forearm circumference lost 75 percent. The time after exercise required for the apparent arm weight to return to within 5 percent of the level of resting was between 8 and 9 min. The subject's failure to relax appears to prevent the arm from manifesting its full apparent weight during the early stages of rest and recovery. To secure data on apparent weight by the method described, therefore entails a rest period of at least 10 min.