Effects of Robotic-Assisted Gait at Different Levels of Guidance and Body Weight Support on Lower Limb Joint Angles, Angular Velocity, and Inter-Joint Coordination

The Lokomat provides task-oriented therapy for patients with gait disorders. This robotic technology drives the lower limbs in the sagittal plane. However, unconstrained gait involves motions also in the coronal and transverse planes. This study aimed to compare the Lokomat with Treadmill gait through 3D-joint kinematics and inter-joint coordination. Lower limb kinematics was recorded in 18 healthy participants who walked at 3 km/h on a Treadmill or in a Lokomat with nine combinations of Guidance (30, 50, 70%) and body-weight-support (30, 50,70%). Compared to Treadmill, the Lokomat altered pelvis rotation, decreased pelvis obliquity and hip adduction, and increased ankle rotation. Moreover, the Lokomat resulted in a significantly slower velocity at the hip, knee, and ankle flexion compared to the treadmill condition. Moderate to strong correlations were observed between the Treadmill and Lokomat conditions in terms of inter-joint coordination between hip-knee (r=0.67-0.91), hip-ankle (r=0.66-0.85), and knee-ankle (r=0.90-0.95). In conclusion, this study showed that some gait determinants such as pelvis obliquity and rotation, and hip adduction are altered when walking with Lokomat in comparison to Treadmill. Kinematic deviations induced by the Lokomat were most prominent at high levels of body-weight-support. Interestingly, different levels of Guidance did not affect gait kinematics.