A very low correlation between GPAQ and accelerator ennoometry was observed in the current study, which was consistent with the study by Cleland et al. , for sedentary time.  An underestimation of sedentary behaviour with GPAQ (1130 min/week) compared to the accelerometer (3365 min/week) and a lack of correlation between the two measures were also reported . A small correspondence between the accelerator effect and questionnaire responses was also found with IPAQ in a large sample of men and women; Participants reported 131 min/day less sedentary time than accelerometer data . There are many possible explanations for the differences between the GPAQ and the accelerometer measured its time. First, accelerometers record all activities below 100 counts/min, including seats and standing, as sitting, while the GPAQ asks only one question on all sitting hours per day, with the exception of downtime. Some accelerometers measure seated time breaks that have been designed to record transitions from sitting time to activity with 100 counts/min as a threshold; However, this is entirely in agreement with position fractures with a posture sensor . It should be noted that, although most studies found an underestimation of self-reported sedentary time, one study found an overestimation of sedentary time compared to adult acceleration data ; and this may be due to memory/forgotten treats. Several sedentary contextual behaviours were investigated  and the 24-hour recall of sitting time was more favourable to weekly recall  for people of university age . While the average wear time in the current study was 14.3 h/day, the minimum wear criterion was only 10 hours per day. Some studies found data based on a 10-hour wear period, which led to a 30% decrease in sedentary time compared to data based on 14 hours/day of wear; Longer accelerometer wear time (i.e.
>13 h/day) was recommended for accurate estimates of daily seat time . In the current study, participants underestimated their self-reported seat time by 204 minutes per day. Several instrument-related factors partly explain the lack of agreement between the GPAQ and accelerometer methods in estimating sedentary time; The division of the GPAQ headquarters issue into several issues in all areas of activity could be a more appropriate strategy and should be considered. This study complements a large number of studies that highlight potential problems in the measure of change. The results indicate that different approaches to assessing the phase of change do not necessarily assess the same underlying constructs and that the measure chosen may have an impact on the level of change assigned to a participant. Further studies are needed to compare versions of drug use in different contexts of change measures, to determine whether different approaches can be more reliable and appropriate in different environments.