An examination of age-related differences in lower extremity joint torques and strains in the proximal femur during gait
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Three studies were performed to investigate age-related changes in neuromuscular function during gait and how these changes affect strains in the proximal femur. Study 1 examined age differences in peak lower extremity joint torques during walking with controlled speed and step length. Studies 2 and 3 applied muscle forces estimated during gait to finite element models of the femur. Study 2 examined age differences in femoral strains, and Study 3 examined the sensitivity of strains to individual muscle forces.
The results support the idea that older adults walk with reduced contributions from the ankle plantar flexors and increased contributions from the hip extensors. Interactions between age and speed indicate that older adults utilized a different neuromuscular strategy than young adults to vary the speed of their gait. No age differences were found for the largest magnitude strains in the proximal femur. However, young adults were able to apply larger loads to the femur without corresponding increases in femoral strains. Strains in the femoral neck were found to be sensitive to muscle forces, particularly hip abductor forces. Strains in the sub-trochanteric region tended to be larger than those in the femoral neck, and less sensitive to muscle forces. These results increase our understanding of neuromuscular changes that occur with age, and the effects of these changes on the femur.
- Doctoral Dissertations