Effects of endurance training on muscle blood flow and metabolism studied in the isolated upper arm muscles

The influence of cardiovascular and muscular adaptations following 8 weeks of high-intensity aerobic training of the upper arm was investigated. 9 female subjects carried out elbow flexion exercise, working in supine position on a special designed arm ergometer, while 11 subjects served as controls. Pulmonary oxygen uptake, arterial diameter, blood velocity and blood flow were recorded. Measurements were accomplished at rest, during two submaximal work-periods (1.0 and 1.5 kg) and at peak work. In addition, strength and force parameters were measured. After 8 weeks of training the parameters were re-tested. The results showed that peak oxygen uptake increased by 28.6 % from pre-to post-test. One repetition maximum and muscle mass increased by 47.3%and 8.0 % compared to pre-training values. There were no differences in blood velocity, arterial diameter and blood flow from pre- to post-test at any work load. Based on the results, it was concluded that the training-induced elevation in oxygen uptake was most likely caused by adaptations at muscular level, since no changes were seen in the blood flow parameters. The results further reveal the high potential for muscular and neural adaptations in untrained muscles.