This investigation sought to assess the relationship between physical activity (PA) and estimated bone stiffness as assessed by multisite quantitative ultrasound (mQUS) in a large cohort. A total of 1177 men and 2949 women were assessed with mQUS (Beam-Med Omnisense quantitative ultrasound; Isreal) at the distal radius, tibia, and phalanx sites as part of the Canadian Multicentre Osteoporosis Study (clinical sites included Saskatoon, Calgary, Hamilton, Quebec City, Halifax and St Johns). Estimated stiffness was provided at each site as speed of sound (SOS, in m/s). Mean estimated weekly hours of moderate PA, vigorous work and strenuous sport in the past year (converted to kcal energy expenditure/week) and mean estimated daily hours of sedentary activity in the past year were gathered by interview. Weekly moderate PA was stratified into lowest (<3000 kcal/w), low (3000 to <6000 kcal/w), moderate (6000 to <9000 kcal/w), high (9000 to <12 000 kcal/w) and highest (≥12 000 kcal/w). Moderate PA, vigorous work and strenuous sport were combined and energy expenditure stratified as above. Lastly, average sedentary hours per day in the past year were stratified into lowest (<10 h/d), low (10 to <15 h/d), moderate (15 to <20 h/d) and high (≥20 h/d). Analysis of variance and Tukey HSD established whether statistical differences among and between groups existed. While there were no significant differences in SOS among groups for mean moderate physical activity per week and mean daily sedentary hours per day, there were significant differences when vigorous work and strenuous sport were added to moderate physical activity.
|Distal radius measure||Lowest mean SOS||Low mean SOS||Moderate mean SOS||High mean SOS||Highest mean SOS|
|≥ Moderate PA||4025||4045*||4055*||4062*||4071*|
|*Significantly different (P<0.05) from lowest mean SOS group.|
A low amount of high-intensity physical activity may increase estimated bone stiffness.
17 May 2014 - 20 May 2014