Strength of trunk and thigh musculature and bone mineral density in women aged 40-79 years

Background: Decreased bone strength together with impaired physical efficiency followed by falls are the most important causes of osteoporotic fractures in elderly population. Objectives: To examine the influence of age on isokinetic trunk and knee flexion and extension torque properties, and to study their associations with bone mineral density in women. Material and methods: 288 women were divided into 4 age groups (40-49, 50-59, 60-69, 70-79 years). Isokinetic concentric studies of spinal and knee extensors and flexors were carried out at 90 degrees/s and 120 degrees/s, for spine, and 60 degrees/s and 180 degrees/s for knees. Bone mineral density was measured in the proximal femur by DXA. Results: The different strength parameters (peak torque, peak torque/body mass, average torque of five repetitions) decreased and the time to reach peak torque increased with age. Some relations have been noted between these isokinetic parameters and bone mineral density. Conclusions: Age-related deterioration in strength-velocity parameters of knee and spinal muscles are co-incidental with a gradual decrease in proximal femur BMD in older women.