VALIDITY OF ACTIVITY MONITORS IN ESTIMATING ENERGY EXPENDITURE DURING TREADMILL WALKING 1488

Current activity monitors lack precision in predicting energy expenditure(EE). It has been suggested that accelerometers measuring activity throughout various planes of motion may be more accurate. The purpose of this study was to determine the accuracy of two ambulatory activity monitors (TriTrac-R3D and ActiWatch) to predict EE in kilocalories (Kcal). Ten healthy subjects (5 males& 5 females) underwent submaximal treadmill testing comprised of six 5-minute stages. The protocol included flat activity at 2.0, 4.0, and 6.0 mph, and 3.0 mph graded exercise at 2.5%, 5.0%, and 10%. Activity monitors were attached at the trunk. Measured Kcals, HR, and RPE were determined each minute. In addition, Kcal estimates were determined using activity monitor output. Measured EE and estimated EE are expressed in mean Kcal/min per stage:Table The correlations between measured Kcal and: TriTric-R3D, ActiWatch, and HR& RPE were r = 0.875, r = 0.796, and R = 0.795 respectively. Energy estimation from both devices correlated well with measured Kcal data, suggesting that both monitors may be useful in assessing ambulatory physical activity. However, the simple measures of HR & RPE are nearly as effective yet economical.