The relationship of level of habitual activity to measures of leanness-fatness, physical working capacity, strength and motor ability in 17 and 18 year-old males.

The relationships between physical working capacity (PWC), level of habitual activity, relative leanness-fatness, isometric strength and motor ability have been examined in 85 17 and 18 year-old school boys. Level of habitual activity was found to be significantly related to PWC and to the strength and motor ability scores, whilst relative leanness-fatness was not significantly related to any of the other variables studied. Some of the apparent association between PWC and the strength and motor ability scores was due to a common dependence on body size, but the relationship between PWC and four performance variables remained significant when the influence of differences in size of the subjects was removed. It is suggested that differences in the level of habitual activity of post adolescent male school boys influence the physical working capacity but not relative leanness-fatness. The association between level of habitual activity and strength and motor ability scores suggests that the latter variables may possibly influence the level of habitual activity in this type of subject.