Does changing gait mechanics in the early impact phase reduce stress fractures for runners?

Research reviewed: Stress fracture injury prevention strategies with emphasis on early impact dampening among endurance runners. Nixon et al

One of the most common injuries for endurance runners are stress fractures of the foot and lower leg. The repetitive motion of running over countless distance leads to repetitive load and impact which can lead to bone stress injuries and eventually to a stress fracture.

In this paper, the researchers looked into that relationship between impact and running-related stress fractures by seeing if changing running gait (mechanics) in the initial loading phase when the foot is first coming into contact with the ground.

Methods

The researchers split male and female runners (roughly 49% male and 51% female) into groups by stress fracture history; non-injured and history of leg and stress fractures and an intervention group of healthy runners.

The runners went through a 1-hour gait modification session with video feedback and verbal cueing focused on optimizing leg and core muscle pre-activation at foot strike.

The researchers were measure for before and after net ground reaction forces (GRF), medial-lateral (inside to outside of the foot/leg) GRP patterns, oscillation frequency and impact loading rates.

Results

Firstly, those with a history of stress fractures had greater GRF during the first 8% of stance phase on both legs/feet and greater medial-lateral GRF during the first 6-17% of stance phase, compared to non-injured runners. Both of these were significant (p<.05). Therefore, it follows that reducing some of these metrics during early stance phase could prove beneficial.

The 1-hour gait modification session, on average, significantly reduced early unloading after foot strike (up to the first 12% of stance phase), reduced mechanical oscillation frequency, reduced load rates by 35.3 BW/s, and reduced limb asymmetries in load rate by 7.9%.

Takeaways

Although there’s much more research needed, what this study shows is there’s potential to reduce the risk for running-related stress fractures via gait modification that focuses on controlling and dampening the impact during early stance phase.