Pitfalls in accelerometer-based measurement of physical activity: The presence of reactivity in an adult population

TY - JOUR

T1 - Pitfalls in accelerometer-based measurement of physical activity: The presence of reactivity in an adult population

AU - Baumann, S

AU - Groß, S

AU - Voigt, L

AU - Ullrich, A

AU - Weymar, F

AU - Schwaneberg, T

AU - Dörr, M

AU - Meyer, C

AU - John, U

AU - Ulbricht, S

N1 - © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

PY - 2018/3

Y1 - 2018/3

N2 - When a behavior is monitored, it is likely to change, even if no change may be intended. This phenomenon is known as measurement reactivity. We investigated systematic changes in accelerometer-based measures over the days of monitoring as an indicator of measurement reactivity in an adult population. One hundred seventy-one participants from the general population (65% women; mean age = 55 years, range: 42-65 years) wore accelerometers for 7 consecutive days to measure sedentary behavior and physical activity (PA). Latent growth models were used (a) to investigate changes in accelerometer wear time over the measurement days and (b) to identify measurement reactivity indicated by systematic changes in sedentary time (ST), light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA). Over the measurement days, participants reduced accelerometer wear time by trend (rate of change [b] = -4.7 min/d, P = .051, Cohen's d = .38), increased ST (b = 2.4 min/d, P = .018, d = .39), and reduced LPA (b = -2.4 min/d, P = .015, d = .38). Participants did not significantly reduce MVPA (P = .537). Our data indicated that accelerometry might generate reactivity. Small effects on ST and LPA were found. Thus, the validity of accelerometer-based data on ST and LPA may be compromised. Systematic changes observed in accelerometer wear time may further bias accelerometer-based measures. MVPA seems to be less altered due to the presence of an accelerometer.

AB - When a behavior is monitored, it is likely to change, even if no change may be intended. This phenomenon is known as measurement reactivity. We investigated systematic changes in accelerometer-based measures over the days of monitoring as an indicator of measurement reactivity in an adult population. One hundred seventy-one participants from the general population (65% women; mean age = 55 years, range: 42-65 years) wore accelerometers for 7 consecutive days to measure sedentary behavior and physical activity (PA). Latent growth models were used (a) to investigate changes in accelerometer wear time over the measurement days and (b) to identify measurement reactivity indicated by systematic changes in sedentary time (ST), light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA). Over the measurement days, participants reduced accelerometer wear time by trend (rate of change [b] = -4.7 min/d, P = .051, Cohen's d = .38), increased ST (b = 2.4 min/d, P = .018, d = .39), and reduced LPA (b = -2.4 min/d, P = .015, d = .38). Participants did not significantly reduce MVPA (P = .537). Our data indicated that accelerometry might generate reactivity. Small effects on ST and LPA were found. Thus, the validity of accelerometer-based data on ST and LPA may be compromised. Systematic changes observed in accelerometer wear time may further bias accelerometer-based measures. MVPA seems to be less altered due to the presence of an accelerometer.

KW - Accelerometry/standards

KW - Adult

KW - Aged

KW - Exercise

KW - Female

KW - Humans

KW - Male

KW - Middle Aged

KW - Reproducibility of Results

KW - Sedentary Behavior

U2 - 10.1111/sms.12977

DO - 10.1111/sms.12977

M3 - SCORING: Journal article

C2 - 28921747

VL - 28

SP - 1056

EP - 1063

JO - SCAND J MED SCI SPOR

JF - SCAND J MED SCI SPOR

SN - 0905-7188

IS - 3

ER -