Physical Fitness, Walking Performance, and Gait In Multiple Sclerosis

Background: Walking impairment is a prevalent and life-altering physical feature of both early and advanced stages of multiple sclerosis (MS). There is evidence that walking speed, endurance, and underlying gait parameters are compromised in persons with MS. There has been recent speculation that physiological deconditioning (i.e., reductions in aerobic capacity, balance, and muscular strength) contributes to walking and gait impairments in this population. 

Objectives: The current study examined the associations among aerobic capacity, balance, and lower limb strength asymmetries, walking performance (i.e., Timed 25-ft Walk (T25FW) performance and 6 Minute Walk (6MW) distance), and spatiotemporal parameters of gait (i.e., velocity, cadence, step length, base of support, and time spent in double support) in 31 persons with MS and 31 controls matched by age, sex, height, and weight.

Methods: Participants underwent testing for measuring peak aerobic capacity (i.e., peak oxygen consumption), muscular strength (i.e., asymmetry between knee muscles), and balance (i.e., postural sway). Walking performance was measured using the T25FW and 6MW tests. Gait parameters were analyzed using a GaitRite™ electronic walkway (CIR Inc.).

Results: There were significant differences in fitness, walking, and gait variables between persons with MS and matched controls. Aerobic capacity, balance, and knee extensor asymmetry were associated with walking performance and gait in the overall sample (r’s = .2 - .7) and in persons with MS (r’s = .2 - .6). Aerobic capacity and knee extensor asymmetry explained group differences in T25FW performance (ΔR² = .28), 6MW distance (ΔR² = .29), and step length (ΔR² = .30), whereas aerobic capacity alone explained group differences in gait velocity (ΔR² = .27) and time spent in double support (ΔR² = .34). Among persons with MS, aerobic capacity and knee extensor asymmetry, but not balance, explained significant variance in walking performance and gait parameters (R²’s = .32 - .58).

Conclusions: Such results support the hypothesis that physiological deconditioning might indeed explain variability in walking disability and latent gait kinematics in persons with MS and the implementation of multimodal exercise training interventions as a modifiable approach for improving mobility outcomes in this population.