Reliability and criterion validity of the Self-Administered Physical Activity Checklist in Greek children

The purpose of this study was to assess the test-retest reliability and criterion validity the Self-Administered Physical Activity Checklist (SAPAC) translated into the Greek language. To evaluate reliability, 72 students (35 girls and 37 boys) of the fifth and sixth grade completed SAPAC on two separate occasions, two weeks apart. Internal consistency was determined with Cronbach alpha coefficient and test-retest reliability with the intraclass correlation coefficient (ICC). To evaluate criterion validity, the RT3 Research Tracker accelerometer was used as standard measure, in 90 randomly selected Greek children (51 girls and 39 boys), aged between 10 and 13. Each subject participated for two consecutive days. On day one, an accelerometer was fitted when school started. On day two, the accelerometers were returned and each subject completed the questionnaire. The internal consistency and the test-retest reliability of SAPAC on total metabolic equivalent (MET) score, MET score of low physical activities (LPA) and MET score of moderate to vigorous physical activities (MVPA) were very satisfactory (all Cronbach's alpha > 0.87, and all ICC > 0.85, P <0.001). The Kendall's tau-b test revealed that the degree of agreement between SAPAC and RT3 accelerometer on total MET score and MET score of MVPA were 0.31 and 0.37, respectively (P <0.01). It was concluded that the Greek translated version of SAPAC is a reliable questionnaire that provides valid estimates of total, as well as moderate to vigorous activities MET scores.