In this study the effects of age (18-55 years), differing levels of fitness (VO 2max ranging from 35.5 to 68.8ml.kg-1.min-1) and endurance training (10 weeks) on heart rate control were investigated. Fitness level was initially determined by a VO2max stress test, succeeded by cold hand and cold face pressor test of autonomic activity. Following these baseline measurements, the subjects (32 nonsmoking male volunteers) were endurance-trained three to four times a week for a 10-week period. The baseline tests were readministered following the 10-week dynamic exercise training period. These data suggest that a natural consequence of aging is a diminishment of autonomic heart rate control; however, endurance training appears to interrupt the aging influence. Individuals of low fitness level appear to have heart rate control dominated by the sympathetic system, while individuals with high fitness levels have a vagally dominated heart rate control system.

Fifteen three-, four-, and five-year olds were assessed for the amount of time they spent on, off, under, and touching play equipment in an environment with play events and one without (i.e. the platform condition), An ABAB experimental design was used. Treatments lasted 3 days a week for 4 consecutive weeks, with each age group being videotaped 20 minutes each day, Data collected from the videotapes was applied to a 3 x 4 (age x treatments) ANOVA and revealed at the . 05 level (a) significantly more on and touching in the play event conditions; (b) significantly greater off and under in the platform (non play event) conditions; (c) a significant increase in off behavior from the first to second play event condition; (d) three-year-olds spent more time under and touching, and significantly less time on; and (e) significant interactions for on and under which seemed to be caused by the three-year-olds showing an inordinate amount of under behavior in the second platform condition, These results supported the assumption that play events would cause a significant increase inactive child-equipment interaction.