Sagittal plane joint mechanics during downhill running in female distance runners

Hill training is often used as a foundational training method to increase strength and speed. However, there is limited research regarding the mechanics involved in downhill running, particularly for declines greater than -10%, despite trail and hill training commonly occurring in long distance running. Thus, the purpose of this study was to quantify the biomechanics of downhill running at four different declines compared to a level surface in female distance runners and to assess the potential risk of injury relative to level running.

In this cross-sectional study, fifteen female distance runners (age: [23.5 ± 4.9] years; mileage: [56.3 ± 20.9] km/week) ran on a force-instrumented treadmill at 4.0 m⋅s^-1 for 2 min at 0%, -5%, -10%, -15%, and -20% grades, with 5 min of rest between conditions. A motion capture system and embedded force plates were utilized to collect angles, moments, and powers at the ankle, knee, and hip in the sagittal plane.

Key study findings showed increased power absorption at the ankle and knee (p < 0.002), decreased hip and knee flexion, and increased trunk extension at initial contact (p < 0.001). There was also a decreased range of motion at the ankle and hip and an increased range of motion at the knee during the stance phase (p < 0.05).

Results indicate that there may be a greater risk for injury when running downhill compared to running on a level surface based on risk factors for common running injuries illustrated in prior research.