Influence of accelerometer location to quantify physical activity in osteoporosis prevention programs

Abstract

Objective: Physical activity has positive effects on bone health. In order to develop osteoporosis prevention programs based on physical activity, exercise intensity must be precisely quantified in order to guarantee its effectiveness as well as to ensure skeletal integrity. The objective has been assessing the influence of the accelerometer location to quantify the intensity of physical activity in osteoporosis prevention programs.

Method: Eighteen premenopausal women completed an exercise protocol consisting of five countermovement jumps followed by four treadmill bouts at different speeds. Participants carried accelerometers located on the wrist and hip, and the acceleration measures recorded at both locations were compared. Three types of analysis were analyzed: 1) Association between measurements from both locations. 2) Level of similarity in group estimates. 3) Evaluation of measurement bias.

Results: Low correlation between peak acceleration measured at hip and wrist in all protocol tests (r= 0.046-0.469, p<0.05). Differences in group estimates and measurement bias between the records of both locations increase as the treadmill speed does.

Conclusions: Acceleration measured in the wrist could overestimate the acceleration produced in the hip. This effect must be taken into account when quantifying mechanical loads in physical activity programs for the prevention of osteoporosis.