Comparison of the anaerobic threshold and mechanical efficiency of running in young and adult athletes.

We determined noninvasively in a laboratory on the treadmill the anaerobic threshold (AT) (ventilatory threshold) and mechanical efficiency (ME) of running in 7 adult male long-distance runners (mean age = 24.1 yrs) and 17 adolescents (17.0 yrs), in 8 adult female middle-distance runners (23.2 yrs), in 12 young (16.1 yrs) and in 28 adult male canoeists (22.8 yrs), and in 10 juniors (17.4 yrs). We did not find significant differences in the metabolic adaptation characterized with the help of % VO2max on the AT level between relatively equally trained juniors and adults. In long-distance runners the % of VO2max on the AT level was 85.3% for adults and 85.2% for adolescents, in female middle-distance runners 82.8% and 82.7%, respectively, in adult canoeists 78.9%, and in juniors 79.8%. In ME which characterizes the degree of adaptation to the running and depends on the years of training and thus on the differences in racing performance, the values were lower for young athletes than for adults. The ME found in long-distance runners was 25.4% for young athletes and 32.4% for adults, in middle-distance runners 28.4% and 30.3%, respectively, and in canoeists 24.5% and 26.7%, respectively. The difference was significant only in long-distance runners where the greatest difference in racing performance (about 15%) is also found. The close similarity in responses to submaximal work intensities in adults and young sportsmen or subjects of equivalent fitness suggests caution in the interpretation of agewise decrements observed in physiologic variables which may be sensitive to physical fitness status.