Reliability and validity of a brief physical activity-assessment for use by family doctors.

Abstract

Objective: To evaluate the reliability and validity of a brief physical activity assessment tool suitable for
doctors to use to identify inactive patients in the primary care setting.
Methods: Volunteer family doctors (n = 8) screened consenting patients (n = 75) for physical activity
participation using a brief physical activity assessment tool. Inter-rater reliability was assessed within one
week (n = 71). Validity was assessed against an objective physical activity monitor (computer science and
applications accelerometer; n = 42).
Results: The brief physical activity assessment tool produced repeatable estimates of ‘‘sufficient total
physical activity’’, correctly classifying over 76% of cases (k 0.53, 95% confidence interval (CI) 0.33 to
0.72). The validity coefficient was reasonable (k 0.40, 95% CI 0.12 to 0.69), with good percentage
agreement (71%).
Conclusions: The brief physical activity assessment tool is a reliable instrument, with validity similar to that
of more detailed self report measures of physical activity. It is a tool that can be used efficiently in routine
primary healthcare services to identify insufficiently active patients who may need physical activity advice.