Energy cost of physical activities in 12-y-old girls: MET values and the influence of body weight

Abstract

BACKGROUND: Few data exist on the energy cost of specific activities in children. The influence of body weight on the energy cost of activity when expressed as metabolic equivalents (METs) has not been vigorously explored. OBJECTIVE: To provide MET data on five specific activities in 12-y-old girls and to test the hypothesis that measured MET values are independent of body weight. SUBJECTS AND METHODS:In 17 12-y-old girls, resting metabolic rate (RMR) and the energy expended while sitting, standing, walking on a flat treadmill at 3.2 and at 4.8 km/h, and walking on a treadmill at a 10% incline at 4.8 km/h were measured using indirect calorimetry. MET values were calculated by dividing the energy expenditure of an activity by the subject's RMR. The influence of body weight was assessed using simple linear regression. Results: The observed METs were more consistent with published values for similar activities in adults than those offered for children. Body weight was a statistically significant predictor of the MET of all three walking activities, but not the MET of sitting or standing. Body weight explained 25% of the variance in the MET value for walking at 3.2 km/h, 39% for walking at 4.8 km/h, and 63% for walking at a 10% incline at 4.8 km/h. CONCLUSION: METs for the three walking activities were not independent of body weight. The use of average MET values to estimate the energy cost of these three activities would result in an underestimation of their energy cost in heavier girls and an overestimation in lighter girls. These results suggest that the estimation of total energy expenditure from activity diary, recall, and direct observation data using average MET values may be biased by body weight.

Energy balance and obesity: a UK perspective on the gluttonyv.sloth debate

“…However, the present review has shown that it is much less good at assessing physical activity behaviour especially within most current population groups which include a majority of Energy balance and obesityoverweight and obese individuals. For these groups the lack of any change in the distribution of PAL values or absolute rates of PAEE is almost certainly concealing marked behavioural changes in activities which are revealed by different methodologies such as accelerometry (68,69) , and are, in fact, easily identifiable if weightcorrected values of PAEE are used instead of PAL. The further development of such methodologies and their application in future DLW studies would markedly improve understanding.…”

“…In fact, it has been argued that it may not be possible to adjust PAEE for size with any confidence and that great caution must be exercised when attempting to do so (67) . In 12-year-old girls the energy cost of walking at fixed speeds increased with body weight, especially at higher walking speeds (68) . In these latter studies MET values (EE/RMR) for walking at a 10 % incline at 4·8 mph for girls of 50 kg was about 40 % higher than girls of 30 kg, an increase which is obviously less than the 66·6 % difference that would have occurred if the MET values were simply corrected by weight.…”

Metabolic rate and clothing insulation data of children and adolescents during various school activities

“…Children data were collected and published by various authors (e.g. Bandini et al 2006, Spadano et al 2003, 2005, Torun, 1989 and are used to calculate daily energy and nutritional requirements. Again, no school related data were available so far and these are provided in this study.…”

“…The values observed in this experiment for theory lessons are higher than the RMR for the age group (Black et al 1996). Spadano et al (2003) The values for the present youngest group, which is a year older and has a higher weight than…”

Symposium on ‘Nutrition and health in children and adolescents’ Session 4: Obesity prevention in children and adolescents The effect of physical activity on body fatness in children and adolescents

“…The assumption underlying the use of PAL is that by adjusting for RMR and expressing the data as a ratio the potential influence of body weight and composition is removed, thus allowing comparisons of the relative energy cost of physical activities between individuals and populations. Although this assumption may be valid for sedentary or low-intensity activities, PAL is not necessarily independent of body weight or FFM (Spadano et al 2003(Spadano et al , 2005, particularly in weight-bearing activities of moderate-vigorous intensity, such as walking Fig. 1.…”