Background: This study aimed to investigate the effect of different levels of weakness in these two muscle groups on spatiotemporal gait parameters in older adults.
Methods: This analytical semi-experimental study was conducted on 48 older adults (24 men and 24 women) with a mean age of 72.4 ± 4.6 years. Muscle strength was measured using a MicroFET2 hand-held dynamometer, and participants were divided into three groups (high, moderate, and low) based on normalized strength. Spatiotemporal gait parameters including gait speed, cadence, step length, stride length, step width, gait cycle time, stance time, and swing time were recorded using a Vicon motion capture system. Data were analyzed using one-way ANOVA, Tukey's post-hoc test, Pearson correlation coefficient, and multiple regression analysis.
Results: Significant differences were observed between the three groups in all parameters except for step width and swing time (P < 0.05). The largest effect size was related to gait speed (η² = 0.40). Knee extensor strength showed a positive correlation with gait speed and step length, while plantar flexor strength showed a positive correlation with stride length (P < 0.01). Regression analysis revealed that knee extensor and plantar flexor strength explained 30% and 8% of the variance in gait speed, and 28% and 7% of the variance in step length, respectively.
Conclusion: Weakness of the plantar flexor and knee extensor muscles significantly affects spatiotemporal gait parameters in older adults. Strengthening both muscle groups is essential in rehabilitation and fall prevention programs.