Can non-disabled adults reproduce the stiff-knee gait of individuals with stroke?

This study investigated whether a mechanical constraint of knee flexion in non-disabled individuals could help with reproducing the gait pattern of individuals with stroke. Eleven non-disabled adults (26.6{+/-}6.5 years old) and 12 individuals with stroke (52.0{+/-}12.8 years old) walked at a self-selected comfortable speed as kinematic and electromyographic data were acquired. Non-disabled adults also walked with an orthosis that limited to 45 degrees of knee flexion. The hip, knee, and ankle joint angles and the muscle activation of the rectus femoris, vastus medialis and lateralis, tibialis anterior, semitendinosus, biceps femoris, and gastrocnemius medialis and lateralis were analyzed. The results demonstrated that non-disabled adults presented similar lower limb excursion to individuals with stroke that affects most joints, although, they displayed a different muscle activation level for most muscles. These results suggest that a mechanical constraint of knee flexion leads to temporal and joint excursion alterations in the lower limb of non-disabled individuals, thereby enabling the reproduction of a gait pattern similar to individuals with stroke. It is also observed that these individuals use different strategies to control muscle activation, which might be related to the lack of control in coordinating muscle activation during gait that is present in individuals with stroke.