Background: This study aimed to investigate kinematic parameters of lower limb joints during gait on inclined surfaces in comparison to level ground.
Methods: In this cross-sectional study, 15 healthy individuals walked with their self-selected speed in level ground with zero slope and two inclined surfaces constructed according to real environments with +8 (uphill) and -8 (downhill) slopes along 8 m. Measured variables included angles of sagittal plane of ankle, knee, and hip joints in different phases of gait through a three-dimensional motion capture system.
Results: Significant differences were seen in uphill walking compared to level-ground walking with their increase in ankle, hip, and knee angles in initial contact, maximum ankle dorsiflexion and plantarflexion, maximum knee flexion in stance phase, and maximum knee extension in swing phase, and also with their reduction in maximum angle of knee flexion in swing along with maximum extension of hip joint (P<0.05). In downhill walking compared to level ground, significant differences were observed for increase of ankle and knee angles at initial contact, maximum ankle dorsiflexion and plantarflexion, maximum knee flexion in stance and swing phases, maximum knee extension in swing, and also decrease of hip extension maximum angle. No significant difference was observed in hip joint angle at initial contact between level and downhill surfaces (P>0.05).
Conclusion: Walking on inclined surfaces clearly affects flexion and extension angles of lower limb joints in different phases of gait, requiring greater movement of joints. These changes are more obvious in uphill than downhill, particularly at initial contact.