In the previous study, the relationship between physical activity, determined by stepping time and count, was related to walking speed. A limitation of this quantification of activity is that it does not indicate the magnitude or intensity of the loading experienced by the body. Potentially, this may be an important factor in determining the effect of activity on health as the effectiveness of the activity is largely dependent on the extent to which mechanical loading is applied to bone and muscle. Therefore it is essential to objectively assess the mechanical loading induced by physical activity.


In previous research we developed a novel method to objectively assess this loading of physical activity. Using this method, we found that the loading dose of physical activities at moderate and vigorous intensity levels is associated with muscle strength and bone density. However, ageing may result in the decline of activities and loading at these intensity levels. The aim of this study was to investigate how ageing influences the loading dose of physical activity at different intensity levels in women.


Thirty-two healthy female participants, with no recent musculoskeletal injury and who were not pregnant were recruited for this study. They were divided into two groups based on their ages: the young group (n = 15, age between 18 and 30 yrs) and the old group (n = 17, age between 50 and 65 yrs). The research was approved under the procedures of the University of Roehampton‟s Ethics Committee. All participants gave written informed consent before participating in the study.