RESUMO
Hindfoot, midfoot, and forefoot motion during the stance phase of walking provide insights into the forward progression of the body over the feet via the rocker mechanisms. These segmental motions are affected by walking speed. Increases in walking speed are accomplished by increasing step length and cadence. It is unknown if taking short, medium, and long steps at the same speed would increase hindfoot, midfoot, and forefoot motion similarly to walking speed. We examined effects of different step lengths at the same preferred walking speed on peak forefoot, midfoot, and hindfoot motions related to the foot rockers. Twelve young healthy adults completed five walking trials under three step length conditions in a random order as feet and lower extremity motion were measured via marker positions for the combined Oxford foot and conventional gait models. Peak hindfoot, midfoot, and forefoot joint angles indicating heel, ankle, and forefoot rockers were identified. When walking at the same preferred speed with increase in step length, there were increases in peak hindfoot-tibia plantarflexion angle (p < 0.001; ηp2 = 0.76) in early stance associated with the heel rocker and peak hindfoot-tibia dorsiflexion angle (p = 0.016; ηp2 = 0.39) in midstance associated with ankle rocker. In late stance, the peak hindfoot-tibia plantarflexion angle, forefoot-hindfoot angle, and forefoot-hallux dorsiflexion angle indicating forefoot rocker motion also increased with step length (p < 0.01). When foot kinematics are compared across different individuals or the same individual across different sessions, researchers and clinicians should consider the influence of step length as a contributor to differences in foot kinematics observed.
