Assessment of energy expenditure for physical activity using a triaxial accelerometer

Med Sci Sports Exerc. 1994 Dec;26(12):1516-23.


A triaxial accelerometer was used to evaluate the relationship between energy expenditure due to physical activity (EEact) and body acceleration during different types of activity. In a laboratory experiment, 11 male subjects performed sedentary activities and walked on a motor driven treadmill (3-7 km.h-1). EEact was calculated from total energy expenditure (EEtot), as measured by indirect calorimetry, and sleeping metabolic rate (SMR): EEact = EEtot--SMR. Body accelerations were measured with a triaxial accelerometer at the low back. Special attention was paid to the analysis of unidirectional and three-directional accelerometer output. During sedentary activities a linear relationship between EEact and the sum of the integrals of the absolute value of accelerometer output from all three measurement directions (IAAtot) was found (r = 0.82, P < 0.001, Sy,x = 0.22 During walking EEact was highly correlated with the integral of absolute accelerometer output in antero-posterior direction (IAAx; r = 0.96, P < 0.001, Sy,x = 0.53 When all examined activities were included in a regression analysis, a strong linear relationship between EEact and IAAtot was found (r = 0.95, P < 0.001, Sy,x = 0.70 Using this relationship, EEact during sedentary activities as well as EEact during walking could be estimated with an accuracy of about 15%. Although sedentary activities and walking represent a large part of normal daily physical activity, the validity and usefulness of the triaxial accelerometer--measuring IAAtot--to predict EEact in daily life must be studied under free-living conditions.

MeSH terms

  • Acceleration
  • Adult
  • Calorimetry / methods
  • Energy Metabolism / physiology*
  • Ergometry / instrumentation
  • Exercise Test
  • Forecasting
  • Humans
  • Male
  • Motor Activity / physiology*
  • Movement / physiology
  • Physical Exertion / physiology*
  • Posture / physiology
  • Regression Analysis
  • Rest / physiology
  • Sleep / physiology
  • Walking / physiology