Adaptations of forearm circulation to varied intensities and sets of heavy exercise

Nine male and five female college students were tested on four occasions to determine the effects of various exhaustive weightlifting stimuli on forearm blood flow as measured by strain-gauge plethysmography. Maximum voluntary dynamic wrist curl strength was determined in the first session, which was followed by random treatments of exercise with 70, 80, and 90% of the weight subjects could curl only one time (1 RM) on three separate days. During each treatment, after a 15-min rest, subjects performed three sets of exercise movements at a pace of 0.5 Hz until voluntary exhaustion. Each set of continuous repetitions was followed by a 166-s recovery period. Blood flows (ml flow X 100 ml tissue-1 X min-1) were determined at 10, 36, 62, 88, 114, 140, and 166 s of recovery. Data were analyzed using ANOVA tests for a three (intensities) by three (sets) complete factorial design with repeated measures on all factors. Generally, 90% flows were significantly (P less than 0.05) lower than both 70 and 80% flows. Also, 70% flows were statistically equal to 80% flows. There were significant (P less than 0.05) set effects at 10, 36, 114, and 166 s of recovery. Blood flows for set 3 exceeded those for set 1 at 10, 36, 114, and 166 s of recovery, and blood flows for set 2 exceeded those for set 1 at 166 s of recovery.