Energy Expenditure of Eight Walking Activities in Normal Weight and Obese High School Students: Using an Indirect Calorimeter and Accelerometers Worn on Ankle and Waist

The purposes of this study were to assess energy expenditure of eight walking activities in normal weight and overweight or obese high school students and to evaluate the accuracy of two accelerometers worn on the ankle and waist. Thirty-five (male 17, female 18) healthy high school students participated in this study. They were classified into normal weight (n=21) and overweight or obese (n=14) groups. The subjects completed five treadmill walking activities (TW2.4, TW3.2, TW4.0, TW4.8, TW5.6), followed by three self-selected hallway walking activities (walk as if walking and talking with a friend: HWL, walk as if hurrying across the street at a cross-walk: HWB, walk as fast as you can but do not run: HWF). Energy expenditure and metabolic equivalents (METs) were measured using a portable indirect calorimeter, and predicted energy expenditures and METs were derived from two accelerometers placed on the ankle and waist. Measured energy expenditures per body weight (kg) of eight walking activities were significantly higher in the normal weight group than in the obese group and significantly higher in female than male. The ankle accelerometer overestimated energy expenditures and METs (bias 49.4~105.5%), whereas the waist accelerometer underestimated energy expenditures and METs (bias −30.3~−85.8). Except for HWF (fast) activity, METs of seven activities were moderate intensity based on Compendium METs intensity categories. HWF (fast) activity was vigorous intensity. METs from the ankle accelerometer were vigorous intensity except TW2.4 activity (moderate intensity). METs from the waist accelerometer were low intensity (TW2.4, TW3.2, TW4.0, TW4.8, HWL) and moderate intensity (TW5.6, HWB, HWF). Physical activity guidelines were developed based on measured physical activity level of high school students. Further studies should investigate the effects of body composition in larger subjects.

Measurement of Energy Expenditure Through Treadmill-based Walking and Self-selected Hallway Walking of College Students - Using Indirect Calorimeter and Accelerometer / 대한지역사회영양학회지

OBJECTIVES: The objective of this study was to assess energy expenditure and metabolic cost (METs) of walking activities of college students and to compare treadmill based walking with self-selected hallway walking. METHODS: Thirty subjects (mean age 23.4 ± 1.6 years) completed eight walking activities. Five treadmill walking activities (TW2.4, TW3.2, TW4.0, TW4.8, TW5.6) were followed by three self-selected hallway walking activities, namely, walk as if you were walking and talking with a friend: HWL (leisurely), walk as if you were hurrying across the street at a cross-walk: HWB (brisk) and walk as fast as you can but do not run: HWF (fast) were performed by each subject. Energy expenditure was measured using a portable metabolic system and accelerometers. RESULTS: Except for HWF (fast) activity, energy expenditures of all other walking activities measured were higher in male than in female subjects. The lowest energy expenditure and METs were observed in TW2.4 (3.65 ± 0.84 kcal/min and 2.88 ± 0.26 METs in male), HWL (leisurely) (2.85 ± 0.70 kcal/min and 3.20 ± 0.57 METs in female), and the highest rates were observed in HWF (fast) (7.72 ± 2.81 kcal/min, 5.84 ± 1.84 METs in male, 6.65 ± 1.57 kcal/min, 7.13 ± 0.68 METs in female). Regarding the comparison of treadmill-based walking activities and self-selected walking, the energy expenditure of HWL (leisurely) was not significantly different from that of TW2.4. In case of male, no significant difference was observed between energy costs of HWB (brisk), HWF (fast) and TW5.6 activities, whereas in female, energy expenditures during HWB (brisk) and HWF (fast) were significantly different from that of TW5.6. CONCLUSIONS: In this study, we observed that energy expenditure from self-selected walking activities of college students was comparable with treadmill-based activities at specific speeds. Our results suggested that a practicing leisurely or brisk walking for a minimum of 150 minutes per week by both male and female college students enable them to meet recommendations from the Physical activity guide for Koreans.