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The objective of this study was to determine the energy expended and intensity of physical activity achieved by adolescent girls while playing on a dance simulation game. Twenty adolescent girls were recruited from a local secondary school. Resting oxygen uptake (VO(2)) and heart rate were analysed while sitting quietly and subsequently during approximately 30 min of game play, with 10 min at each of three increasing levels of difficulty. Energy expenditure was predicted from VO(2) at rest and during game play at three levels of play, from which the metabolic equivalents (METS) of game playing were derived. Mean +/- standard deviation energy expenditure for levels 1, 2, and 3 was 3.63 +/- 0.58, 3.65 +/- 0.54, and 4.14 +/- 0.71 kcal . min(-1) respectively, while mean activity for each level of play was at least of moderate intensity (>3 METS). Dance simulation active computer games provide an opportunity for most adolescent girls to exercise at moderate intensity. Therefore, regular playing might contribute to daily physical activity recommendations for good health in this at-risk population.

The literature suggests that the oxygen uptake (VO2) response to the onset of moderate-intensity exercise may be both mature from childhood and independent of sex. Yet the cardiorespiratory response to exercise and the metabolic profile of the muscle appear to change with growth and development and to differ between the sexes. The aim of this study was to investigate further changes in the VO2 kinetic response with age and sex. Participants completed a series of no less than four step change transitions, from unloaded pedalling to a constant work rate corresponding to 80% of their previously determined ventilatory threshold. Each participant's breath-by-breath responses were interpolated to 1 s intervals, time aligned and then averaged. A single exponential model that included a time delay was used to analyse the averaged response following phase 1 (15 s). Participants with parameter confidence intervals more than +/- 5 s were removed from the sample; the results for the remaining 13 men and 12 women (age 19-26 years), 12 boys and 11 girls (age 11-12 years) were used for statistical analysis. Children had a significantly shorter time constant than adults, both for males (19.0+/-2.0 and 27.9+/-8.6 s respectively; P<0.01) and females (21.0+/-5.5 and 26.0+/-4.5 s respectively; P<0.05). There were no significant differences in the time constant between the sexes for either adults or children (P>0.05). A significant relationship between the time constant and peak VO2 was found only in adult males (P<0.05). A shorter time constant in children may reflect an enhanced potential for oxidative metabolism.