Comparison between preferred and energetically optimal transition speeds in adolescents.

The primary focus of this investigation was to determine whether differences exist between the preferred transition speed (PTS) and the energetically optimal transition speed (EOTS) in a group of adolescents. Ten 11-, ten 13-, and ten 15-year-olds completed four testing sessions. Following 30 min of accommodation to treadmill walking and running (session 1), the PTS between walking and running was identified in session 2. In session 3, subjects walked on a level treadmill at 70%, 80%, 90%, 100%, and 110% of respective PTS, while in session 4, children ran on a level treadmill at 90%, 100%, 110%, 120%, and 130% of respective PTS. During the last 2 min of each 5-min walking and running bout, expired gas samples were collected in a meteorological balloon and analyzed to calculate VO2 and the EOTS between walking and running. Data analyses revealed that mean EOTS was significantly higher than mean PTS within each age group. Furthermore, when subjects changed gaits, the aerobic demand needed to run at the PTS was not lower than the VO2 measured while walking at the PTS. A moderately strong positive coefficient (r = 0.71) between leg length and PTS was also observed. Taken together, these data suggest factors other than govern the walk-run transition in adolescent boys and girls.