The effect of trunk resistive exercise on muscle strength in postmenopausal women

At the time this study was conducted. Ms. O'Dwyer and Ms. Lin were physical therapy master's degree students. Dr. Blanpied was a doctoral student. This paper was presented at the First International Orthopaedic Symposium in Ottawa, Canada, in May, 1990. This study was supported by Grant RR59 from the General Clinical Research Centers Program, Division of Research Resources, NIH, and by an Aging Seed Grant from The University of Iowa.Fifty-five women with an average age of 56 years participated in a study to determine the effects of a quantitatively based home exercise program on trunk muscle strength. The same body positions were used for testing trunk strength and for the exercise program. During the strength tests, the external forces generated by the subjects were measured using the trunk attachment of the Muscle Evaluation and Exercise Dosimeter (MEED) 3000 System. The standardized exercise program utilized the body segments and cuff weights on the extremities to achieve the desired resistance level for the sit-up, prone trunk extension, and double-leg flexion exercises. Three sets of 10 were performed for each exercise at least three times a week over a 12-month period. Large, significant (p < .05) strength gains (25-30%) were made by the exercise group for each exercise. The performance of the exercise group was superior to the control group. The reliability of the strength-using tests determined by interday trials using the MEED 3000 was high-all correlations were r = .93 or higher. This study demonstrates that older women can tolerate and increase trunk muscle strength using controlled, progressive, resistive exercise over a long period of time. The exercise approach in this study might be considered for use in treatment of low back dysfunction. J Orthop Sports Phys Ther 1991;13(6):300-309.