Correlation between balance, lower limb muscle strength, and energy cost of walking in stroke survivors: An analytical cross-sectional study.

Abstract

Background: Stroke is a leading cause of disability worldwide and frequently results in impaired balance, reduced lower limb muscle strength, and inefficient gait patterns which contribute to an increased energy cost of walking. Understanding the relationship between balance, muscle strength, and energy expenditure during walking is important for developing targeted rehabilitation strategies for stroke survivors.

Objective: To examine the correlation between balance, lower limb muscle strength, and the energy cost of walking in stroke survivors.

Methods: This analytical cross-sectional study included 48 stroke survivors (≥3 months post-stroke) able to walk independently or with assistance (FAC 3–5) at Rehman Medical Institute. Participants with acute stroke, leg pain, impaired balance (Postural Assessment Scale <12.5), or cognitive deficits (MMSE <24) were excluded. Lower limb strength was measured using MRC-MMT, balance with the short-form Berg Balance Scale, and energy cost with the Physiological Cost Index (PCI). Pearson correlation analyzed relationships between variables, with p < 0.05 considered significant.

Results: Balance demonstrated significant positive correlations with knee extensor strength (r = 0.306, p = 0.034) and knee flexor strength (r = 0.318, p = 0.028). PCI showed significant negative correlations with all lower limb muscle strength measures, including hip extensors (r = −0.534), hip flexors (r = −0.529), knee extensors (r = −0.511), knee flexors (r = −0.531), ankle dorsiflexors (r = −0.499), and plantar flexors (r = −0.502) (p < 0.001). Strong intercorrelations were also observed among different lower limb muscle groups.

Conclusion: Lower limb muscle strength, particularly knee muscle strength, plays a significant role in balance and walking efficiency in stroke survivors. Increased muscle strength is associated with reduced physiological cost of walking, highlighting the importance of strength-focused rehabilitation interventions to improve functional mobility after stroke.