Validation of a physical activity measurement instrument and proposal of percentiles for its evaluation in university students

Introduction: The aim of this study was: a) to validate the questionnaire that measures physical activity by means of confirmatory analysis; b) to analyze reliability by means of stability measures; and c) develop percentiles by age and sex range. Material and Methods: A cross-sectional descriptive study was carried out in 1,937 in university students (1,064 men and 873 women) from the city of Puno, Peru. The weight and height were measured and the Body Mass Index (BMI) was calculated by sex. An 11-question questionnaire was used that measures physical activity. It was validated by Factorial Confirmatory Analysis (FCA) and reliability was verified by test re-test. Percentiles were generated by age and sex range for AF patterns by the LMS method. Results: For the FCA, saturations were observed between 0.41 and 0.96, Eigen values greater than 1.0, and the variance explanation was 63.9% (Varimax and Kaiser-Meier-Olkin, KMO=0.872. Sphericity of chi(2) =4,999.5, p <0.0000). Reliability by re-test showed a Technical Measurement Error (TME) of 2.48 to 3.68% and an intra-class correlation coefficient (ICC) between 0.65 for men and 0.654 for women and for both sexes CCI=0.92. Conclusions: The questionnaire of 11 questions that measures physical activity is valid and reliable for university students in a high altitude region of Peru. In addition, the proposed percentiles serve to identify and classify physical activity levels according to age and sex range.