Abstract
This study aimed to determine whether a drill alternating between uphill and horizontal running reduced knee flexion on ground contact during running on level ground in long-distance runners. Seven long-distance runners ran on a treadmill at 12 km/h, alternating four times between a 6% incline and a level surface. Before and after this intervention, running videos were captured in the sagittal plane to calculate the coordinates of the hip, knee, and ankle joints, and to determine the knee joint angle. Knee collapse was represented by the amount of knee flexion from ground contact to the position of maximum flexion. As a result, knee collapse was significantly reduced from 21.6 ± 6.0 degrees before the intervention to 18.5 ± 4.6 degrees after the intervention. Additionally, the degree of knee collapse before the intervention was significantly correlated with the relative change after the drill (r = 0.82, p < 0.05) . These findings suggest that alternating between uphill and level running reduces knee joint flexion during level running, with the greatest improvement observed in runners who exhibited greater joint flexion during level running before the drill.
