Aim
Toe walking is the way of gait only with toes touching the floor during stance phase. Various neurological and musculoskeletal disorders, such as cerebral palsy, muscular dystrophy can induce pathologic toe walking, called equinus gait, which is known to lead to the foot kinematic changes. To know the foot kinematic changes which pathologic toe walking could generate, we should first understand the foot kinematics during toe walking in the able-bodied. The purpose of this study was to compare the foot kinematics between toe walking and heel-toe walking in the able-bodied using the Oxford foot model, to get inspired for the pathomechanisms of equinus gait in various disorders.
Subjects and Methods
Twenty young healthy adults (10 males and 10 females, age 23.1 ± 2.5 years old) were recruited for this study. The subjects walked in three conditions: heel-toe walking, comfortable height toe walking and maximum height toe walking. They walked at self-selected comfort speed through 10-meter pathway in the motion analysis laboratory. Each trial was recorded using a 6-camera motion analysis system (MX-T10, Vicon, UK) and kinematic data were calculated. A modified Helen Hayes marker set for lower limbs and Oxford Foot Model for foot and ankle were used for analysis (Fig. 1).
Results
The foot kinematics of heel-toe walking, comfortable height toe walking and maximum height toe walking were showed in Fig. 2. and the conventional kinematics were showed in Fig. 3. In the foot kinematics, forefoot plantarflexion to hindfoot significantly increased in toe walking compared to heel-toe walking during loading response phase (p<0.05). Hindfoot internal rotation to tibia significantly increased in toe walking especially during mid- to terminal stance phase (p<0.05). However, in coronal plane, there was no significant increase of hindfoot inversion to tibia and forefoot supination to hindfoot in toe walking during the gait cycle. In the conventional kinematics, there was no significant increase of knee extension in toe walking during stance phase.
Conclusions
We evaluated the foot kinematics using Oxford foot model to understand the biomechanics of foot during toe walking of the able-bodied. The foot kinematics were changed in able-bodied toe walking compared to heel-toe walking in sagittal and transverse plane due to muscular actions of ankle plantarflexors and joint structures of foot. These findings were different from the pathologic equinus gait reported in the previous studies. Therefore, this study might help to distinguish pathomechanism of equinus gait in various disorders from physiologic change in toe walking itself.
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Fig 1. Oxford foot model markers position on the leg, ankle, and foot
Fig 2. Mean kinematic angle of hindfoot relative to tibia, forefoot relative to hindfoot, and hallux relative to forefoot during the gait cycle in 20 participants. In each graph, the mean kinematic angle is plotted for Heel-toe walking (HW) (black), Comfortable height toe walking (CTW) (red), Maximum height toe walking (MTW) (blue) and shaded areas indicated ± 1 SD. Statistically significant difference is represented by the bar below the curve for HW vs CTW (light gray), CTW vs MTW (gray), HW vs MTW (black). Statistically insignificant differences between walking conditions is represented by the white bar. All kinematic angle curves are normalized over the gait cycle. (A), sagittal plane; (B), coronal plane; (C), transverse plane.
Fig 3. Mean kinematic angle of pelvis, hip, and knee during the gait cycle in 20 participants. In each graph, the mean kinematic angle is plotted for HW (black), CTW (red), MTW (blue) and shaded areas indicated ± 1 SD. Statistically significant difference is represented by the bar below the curve for HW vs CTW (light gray), CTW vs MTW (gray), HW vs MTW (black). Statistically insignificant differences between walking conditions is represented by the white bar. All kinematic angle curves are normalized over the gait cycle. (A), sagittal plane; (B), coronal plane; (C), transverse plane.
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