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 .
Estimating absolute and relative physical activity intensity across age via accelerometry in adults.
This study examined the predictive validity of accelerometers ( ACC ) to estimate physical activity intensity ( PAI ) across age and differences in intensity predictions when expressed in relative and absolute PAI terms . Ninety adults categorized into 3 age groups ( 20 - 29 , 40 - 49 , and 60 - 69 yr ) completed a treadmill calibration study with simultaneous ACC ( 7164 Actigraph ) and oxygen-consumption assessment . Results revealed strong linear relations between ACC output and measured PAI ( R2 = .62-.89 ) across age and similar ACC cut-point ranges across age delineating absolute PAI ranges compared with previous findings . Comparing measured metabolic equivalents ( METs ) with estimated METs derived from previously published regression equations revealed that age did not affect predictive validity of ACC estimates of absolute PAI . Comparing ACC output expressed in relative vs. absolute terms across age revealed substantial differences in PAI ACC count ranges . Further work is warranted to increase the applicability ofACC use relative to PAI differences associated with physiological changes with age
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 .