Bone, Volume 30 Issue 6 (June 2002) Pages 836-841

Stronger back muscles reduce the incidence of vertebral fractures: a prospective 10 year follow-up of postmenopausal women

M. Sinaki, et al.

Introduction
We hypothesized that: (1) stronger back muscles could reduce the risk of vertebral compression fractures; and (2) some of the muscle strength achieved through strengthening exercises may persist even several years after cessation.

The objective of this prospective study was to determine the long-term protective effect of stronger back muscles on the spine. In this controlled trial, 8 years after cessation of a 2 year course of back-strengthening exercises, we investigated whether increased muscle strength had any effect on the development of age-related changes such as muscle strength, BMD [bone mineral density], or development of vertebral compression fractures.

Physical activity
Routine weekly physical activity was assessed through the use of a questionnaire based on a previously published standardized scale (Physical Activity Score) that reflects the total level of daily physical activities, including homemaking (0–6), job (0–6), and sports (0–6). 26 This questionnaire has been designed to assess the level of daily physical activity by converting the amount of weight-lifting and walking involved in housework, job, and sports into METs (1 MET is the metabolic oxygen requirement under basal conditions, which is equal to the basal metabolic rate).

Discussion

In this study, we evaluated the long-term effect of stronger back muscles on the spine in estrogen-deficient women. The data showed that although vertebral bone loss was comparable in both groups, the BE [back-exercise] group had fewer than half as many vertebral fractures as the control group, even 8 years after cessation of the back-strengthening exercises.