Physiological and perceptual responses to graded treadmill and cycle exercise in male children

The assessment of ventilatory threshold (Tvent) and maximal oxygen consumption (VO2max) are routine laboratory procedures, yet there are few studies that have directly compared these measurements during different modes of exercise in children. Therefore, the purpose of this study was to compare the physiological and perceptual responses at Tvent and V02max during treadmill and cycle ergometry in prepubertal male children. Ten subjects (M ± SD, 10.2 + 1.3 yrs.) performed a graded exercise test to maximal effort on a treadmill and a cycle ergometer. The order of testing was counterbalanced. The treadmill protocol began at 3.0 mph and 2% grade and progressed in one minute stages. Similarly, the cycle protocol began at 30 watts (W) and progressed 10 W•min-1. For both protocols, each stage was designed to elicit an approximately 3.5 ml-kg-I- min-1 change in V02. In addition, finger stick blood samples were taken at 2, 3, and 5 minutes post exercise in order to assess maximal blood lactate (La) level. Mean V02max on the treadmill (58.2 ± 6.9 ml•kg-l.min-1) was greater (P < 0.05) as compared to the cycle (51.7 ± 7.7ml.kg-'•min-1), with the average difference and the cycle ergometer, V02max is a function of the testing modality. LiKewise, the V02 at Tvent is dependent on the mode of exercise, while Tvent expressed as a percentage of VO2max is independent of mode of exercise. The perceptual responses at Tvent appear to be linked to a percentage of V02max, rather than an absolute V02.School of Physical EducationThesis (M.S.