For total EE , correlation coefficients were statistically significantly lower in uniaxial compared to multisensor devices .
For active EE , correlations were slightly but not significantly lower in uniaxial compared to triaxial and multisensor devices .
The high level of heterogeneity in the validation studies is only partly explained by the type of activity monitor and the activity monitor outcome .
Triaxial and multisensor devices tend to be more valid monitors .
The assessment of physical activity in healthy population s and in those with chronic diseases is challenging .
The aim of this systematic review was to identify whether available activity monitors ( AM ) have been appropriately vali date d for use in assessing physical activity in these groups .
Physical activity-related energy expenditure with the RT3 and TriTrac accelerometers in overweight adults.
OBJECTIVE The objective was to evaluate two accelerometers , the RT3 and the TriTrac-R3D for their ability to produce estimates of physical activity-related energy expenditure ( PAEE ) in overweight/obese adults . RESEARCH METHODS AND PROCEDURES PAEE estimates from both accelerometers were obtained in two experiments . In Experiment 1 , 13 overweight/obese subjects ( BMI 34.2+/-6.4 kg/m2 ) were monitored over 2 weeks in everyday life , PAEE being simultaneously measured by the doubly labeled water method ( DLW ) . In Experiment 2 , 8 overweight/obese subjects ( BMI 34.3+/-5.0 kg/m2 ) and 10 normal-weight subjects ( BMI 20.8+/-2.1 kg/m2 ) were monitored during a treadmill walking protocol , PAEE being simultaneously measured by indirect calorimetry . RESULTS In Experiment 1 , there was no significant difference between methods in mean PAEE ( DLW : 704+/-223 kcal/d , RT3 : 656+/-140 kcal/d , TriTrac-R3D 624+/-419 kcal/d ) . The relative difference between methods ( accelerometer vs. DLW ) was -17.1%+/-16.7 % for the RT3 and -20.0+/-44.6 % for the TriTrac-R3D . Correlation for PAEE between RT3 and DLW was higher than between TriTrac-R3D and DLW ( r=0.67 , p<0.05 and r=0.36 , p=0.25 , respectively ) . The 95 % confidence interval ( CI ) ( kcal/d ) of the mean difference between methods was large , amounting to -385 to 145 for the RT3 and -887 to 590 for the TriTrac-R3D . In Experiment 2 , both accelerometers were sensitive to the changes in treadmill speed , with no significant difference in mean PAEE between methods in overweight/obese subjects . CONCLUSIONS Although both accelerometers did not provide accurate estimates of PAEE at individual levels , the data suggest that RT3 has the potential to assess PAEE at group levels in overweight/obese subjects
For total EE , correlation coefficients were statistically significantly lower in uniaxial compared to multisensor devices .
For active EE , correlations were slightly but not significantly lower in uniaxial compared to triaxial and multisensor devices .
The high level of heterogeneity in the validation studies is only partly explained by the type of activity monitor and the activity monitor outcome .
Triaxial and multisensor devices tend to be more valid monitors .
The assessment of physical activity in healthy population s and in those with chronic diseases is challenging .
The aim of this systematic review was to identify whether available activity monitors ( AM ) have been appropriately vali date d for use in assessing physical activity in these groups .