This study evaluated the aerobic demands of the 20-minute steady-state jogging speeds for 15 high school students. All subjects performed a discontinuous treadmill test that included submaximal speeds, the Fit Youth Today criterion referenced speeds, and finally a run to voluntary fatigue. Stages lasted 5 minutes. Preliminary data indicated that both groups averaged between 87% (the 9 boys) and 93 % (the 6 girls) of their respective peak oxygen consumption at the criterion referenced speeds during treadmill testing. According to the American College of Sports Medicine guidelines for healthy adults, these intensities represent the upper threshold for aerobic conditioning, and high exercise intensities can increase the risk of injury. Although the results of this study are preliminary in nature and based on a small sample size, we suggest that the criterion referenced distances (speeds) for the FYT 20-minute steady-state jog may need modification.
John L. Walker, Tinker D. Murray, Charles M. Johnson, Don L. Rainey and William G. Squires Jr.
Jennifer N. Ahrens, Lisa K. Lloyd, Sylvia H. Crixell and John L. Walker
People of all ages and fitness levels participate regularly in aerobic-dance bench stepping (ADBS) to increase fitness and control body weight. Any reasonable method for enhancing the experience or effectiveness of ADBS would be beneficial. This study examined the acute effects of a single dose of caffeine on physiological responses during ADBS in women. When compared with a placebo, neither a 3- nor a 6-mg/kg dose of caffeine altered physiological responses or rating of perceived exertion (RPE) in 20 women (age 19–28 y) of average fitness level, not habituated to caffeine, while they performed an ADBS routine. Since neither dose of caffeine had any effect on VO2, Vco2, minute ventilation, respiratory-exchange ratio, rate of energy expenditure, heart rate, or RPE during ADBS exercise, it would not be prudent for a group exercise leader to recommend caffeine to increase energy cost or decrease perception of effort in an ADBS session. Furthermore, caffeine ingestion should not interfere with monitoring intensity using heart rate or RPE during ADBS.