Knee muscle strength in multiple sclerosis: relationship with gait characteristics

[Purpose] To investigate the relationship between isokinetic knee muscle strength and kinematic, kinetic and spatiotemporal gait parameters of patients with multiple sclerosis (MS). [Subjects and Methods] Twenty-nine MS patients (mean age 31.5±6.5) were investigated in this study. The isokinetic knee muscle strength and gait parameters of MS patients with moderate and severe disability, as determined by the expanded disability status scale (EDSS): EDSS=1-4.5 (n=22, moderate disability) and EDSS>4.5 (n=7, severe disability) were measured. [Results] Isokinetic knee muscle strength, kinematic, kinetic and spatiotemporal gait parameters differed between moderate (EDSS=1-4.5, n=22) and severe disability (EDSS>4.5, n=7). The correlation between each of gait speed, stride length, total range of knee joint movement and the four strength parameters (minimum and maximum quadriceps and hamstring muscle strengths) were significant for the MS group as a whole. Within subgroups, the correlation between minimum hamstring strength and total range of knee movement was significant only in group EDSS>4.5; minimum hamstring correlated with peak knee extensor moment in group EDSS=1-4.5, but at a reduced level of significance. [Conclusion] The present study revealed significant correlations between gait characteristics and isokinetic strength parameters of the quadriceps and hamstring muscles. Our study suggests that rehabilitation protocols for MS patients should include a critical strength training programme particularly for the hamstring and quadriceps muscles.