This study examined the changes in the physiological profile of children engaged in organized sporting activity compared to a group of normally active children. Eight children (mean age 11.4 yrs) from each of four popular sports in Australia (badminton, basketball, netball, and tennis) and an equal number of nontraining children were monitored over a 12-week season. Very few differences occurred between the sporting groups and the control group. No change was reported between groups in peak oxygen uptake at the start and completion of the season. Changes occurring within each group did not consistently reflect any sport-specific characteristics over the season. Flexibility improved significantly, with an average gain of 3.76 cm in all groups except basketball players, who gained only 0.69 cm for the 12 weeks. Anaerobic power demonstrated significant improvement only within those sporting groups whose training specifically included explosive based activity. It is suggested that the active nature of the control children and use of only 12 weeks of data collection could have contributed to the limited physiological differences observed between active sporting and nonsporting children.