Two studies examined early physical activity (PA) influence on adult PA. PA reduces health risk; thus, identifying precursors to PA are important.;PA engaged time, sampling and the person who influenced children to initiate an activity was compared in college males who had been diagnosed with Attention Deficit Hyperactivity Disorder (ADHD) and matched controls. The ADHD group spent significantly more hours in PA as children and adults than the controls. Sampling during childhood was correlated with adult PA, and both sampling and PA engaged time were relatively stable across the years of age from 6 through 17 and to the previous year in college. ADHD males participated in more individual sports than non-ADHD males, this explained most of the difference between the groups. The two groups participated in an equal number of other activities (OA) (e.g., music, scouts). Family was the primary influence for both groups to initiate OA. For sport the only influence above chance was self.;In the second study the same survey and dependent variables were used to examine gender and group differences comparing physical education teaching majors (PETM) to other secondary education teaching majors (SETM). A love of sport and a sport background has been hypothesized as a factor in selecting physical education as a major. Males in the general population are more active than females, with small differences during childhood and large differences emerging during adolescence. The PETM group was more engaged in PA at every age than the SETM group. The PETM group began sampling at age 6 years and increased sampling through the previous year in college. The SETM followed a pattern similar to the general population where sampling increased from 6-14 years and decreased after 15 years of age. There was a marked difference in both groups between, before, and after 12 years of age in sampling and PA. Family members were the most influential for initiating sport, however peers also were a significant factor. The two groups did not differ on the number of OA. These activities were initiated as a result of influence by parents and self.