Specificity of the anaerobic threshold in endurance trained cyclists and runners

This study examined the specificity of maximum aerobic power and the anaerobic threshold (AT) in 10 endurance-trained cyclists and 10 endurance-trained runners who performed continuous progressive work tests on the bicycle ergometer and treadmill. Dependent 't' tests for VO2max l/min-1 indicated that the cyclists scored higher on the bicycle ergometer (X = 4.5 l/min-1) than the treadmill (X = 4.34 l/min-1) but the difference was not statistically significant. By contrast, the runners fared significantly better (p less than 0.05) on the treadmill (X = 68.1 ml/kg . min-1) compared with the bicycle ergometer (X = 61.7 ml/kg . min-1). When the AT was expressed as a percentage of VO2max, there were no significant differences between the cyclists (66.3%) and runners (61.2%) on the bicycle ergometer or the runners (77.3%) and cyclists (74.3%) on the treadmill. However, this tendency for the better score to be registered by the group tested on the activity for which it trained was most pronounced when the AT was expressed in l/min-1 and ml/kg . min-1. Independent 't' tests accordingly indicated that the cyclists (3.0 l/min-1) had significantly (p less than 0.05) greater AT's than the runners (2.56 l/min-1) on the bicycle ergometer whereas the runners (52.7 ml/kg . min-1) had significantly (p less than 0.05) higher AT's than the cyclists (46.8 ml/kg . min-1) on the treadmill. These data suggest that the adaptive responses to exercise are in part a function of the specific movement patterns executed in training. Thus, if VO2max and the AT are to be measured in the laboratory, the tests must allow optimal innervation of the specifically trained muscle fibres.