Chest
Clinical InvestigationsOxygen Uptake Plateau during Maximal Treadmill Exercise in Children
Section snippets
METHODS
Twenty-one healthy children volunteered for treadmill testing. All were active, nonobese, and not participating in endurance training programs. None was taking medications which would influence exercise performance.
Exercise to exhaustion was performed with a continuous, progressive treadmill walking protocol in an air-conditioned laboratory (temperature 20 to 22° C). After receiving testing instructions, each subject was acclimated to the treadmill with a 2-min walk at 0 percent grade, 3.0 mph.
RESULTS
The average age of the subjects was 9.4 years (range 7.9 to 10.6), with a mean weight of 33.4 kg (SD 7.8) and height 139 cm (SD 7). Nine were boys and six were girls. Average peak Vo2 for the boys was 52.1 ml kg−1 min−1 (SD 5.7) and 49.0 ml kg−1 min−1 (SD 4.5) for the girls. It was the opinion of the testing staff that all subjects achieved at least a near-maximal exercise effort as indicated by unsteady gait, sweating, and breathlessness. All demonstrated an RER over 1.01 and/or heart rate
DISCUSSION
Previous studies have indicated that from 21 to 60 percent of children will demonstrate a Vo2 plateau during a progressive continuous treadmill exercise test (Table 2). The finding of a plateau in 33 percent of subjects in the present study utilizing a ramp protocol is therefore consistent with earlier reports, which have all involved multistage steady-state protocols. It should be noted that while the appearance of a Vo2 plateau has been considered less common in children than adults, a
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