Measurement of Exercise Intensity with a Tri-Axial Accelerometer during Military Training
Abstract
Exercise load and intensity, as reflected in energy expenditure, are determinants of performance. Here, we evaluated a newly developed tri-axial accelerometer for movement registration (Directlife, Philips Research, Eindhoven, The Netherlands) for the assessment of exercise intensity and exercise load at high-intensity field training. Subjects were 16 well-trained men with a mean ( SD) age of 24 3 y and body fat of 15.8 2.1 %. Physical activity was monitored continuously with accelerometers for a twelve-day interval while total energy expenditure was measured simultaneously with the doubly labelled water technique. Subjects did wear three accelerometers, 3 x 3 x 1 cm and 13 g each, at three different locations, trouser pocket, waist belt and breast pocket. Accelerometer output was stored over one-minute intervals and loaded to a computer at the end of the training interval. Urine samples were collected at baseline, before drinking the doubly labeled water as a last drink of the day, on the subsequent day and at further four-day intervals. Urine samples were analyzed with Isotope Ratio Mass Spectrometry. There was a significant body weight loss of 2.0 1.4 kg (P < 0.001) over the twelve-day interval, indicating the intensity of the training. The physical activity level, total energy expenditure as a multiple of predicted basal metabolic rate, was with a mean of 2.5 0.1 around the upper limit for sustainable lifestyles. Variance in activity energy expenditure, calculated as total energy expenditure minus resting expenditure, was explained for 73 % (P < 0.001) by body mass. Adding accelerometer output to the model raised the explained variance to 85 % (P < 0.05) by including body acceleration measured with the waist- device. In conclusion, after adjusting for differences in body mass, the newly developed tri-axial accelerometer for movement registration explains nearly halve of the variance in exercise intensity and exercise load at high-intensity field training.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 2009
- Accession Number
- ADA567660
Entities
People
- Gerard J. Rietjens
- Klaas R. Westerterp
- Loek Wouters
Organizations
- Maastricht University