The effects of the level of physical activity on calcaneal ultrasound measurements: bone properties of medical and physical education students.

The aim of the study was to compare bone properties of two groups of students which strongly differ in the level of their everyday physical activity; the School of Medicine (SM) students and the Faculty of Physical Education (FPE) students, University of Zagreb. Quantitative ultrasound parameters--broadband ultrasound attenuation (BUA) and speed of sound (SOS) were measured. Quantitative ultrasound index (QUI) and estimated bone mineral density (BMD) were calculated by the device software. The final study sample consisted of 165 students from SM (94 males and 71 females) and 215 students from the FPE (164 males, 51 females). Sixty eight percent of FPE students and 21% of SM students reported a high level of everyday physical activity (P < 0.001). All ultrasound parameters were significantly higher in FPE students than in SM students (at the P < 0.001 level). The multiple regression model of the QUI confirmed that the school students attended was the single significant predictor variable for both genders. Our data indirectly showed the beneficial role of physical activity on bone properties.