Asymmetries Identified in Sit-to-Stand Task Explain Physical Function After Hip Fracture

Area of Science:

• Gerontology
• Biomechanics
• Rehabilitation Medicine

Background:

• Physical function after hip fracture is influenced by demographic and functional factors.
• Weight-bearing asymmetries and muscle imbalances are linked to limited mobility and increased fall risk post-hip fracture.
• Traditional mobility measures assess whole-body movement, while limb-specific contributions are often overlooked.

Purpose of the Study:

• To investigate the predictive value of sit-to-stand task (STST) asymmetry for physical function after hip fracture.
• To determine if STST asymmetry predicts performance on the modified Physical Performance Test (mPPT) and stair climb test (SCT) beyond known predictors.

Main Methods:

• Thirty-one community-dwelling older adults (mean age 77.7 years) 2-8 months post-hip fracture participated.
• Participants performed an STST using a force-plate embedded chair to measure limb asymmetry.
• Regression analyses were used to assess the contribution of STST asymmetry to mPPT and SCT scores.

Main Results:

• Age, gait speed, knee extension strength, balance confidence, and functional self-report were significant predictors of both mPPT and SCT.
• STST asymmetry did not significantly predict mPPT scores (P = .23).
• STST asymmetry explained 7.1% of the variance in SCT scores (P < .005).

Conclusions:

• Lower extremity asymmetry during STST significantly predicts performance on the stair climb test (SCT), a high-demand functional task.
• Asymmetry did not predict performance on the modified Physical Performance Test (mPPT) in this sample.
• Reducing weight-bearing asymmetry during rehabilitation may enhance functional recovery and improve outcomes after hip fracture.