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Changing how runners' feet strike the ground can reduce knee pain



Increased participation in running has led to more injuries


Running has been steadily growing in popularity over the past few decades, and it is now one of the most popular forms of physical activity. To put this growth in perspective, more than 15 million Americans participated in running events in 2012, compared to only 4.6 million in the 1990s. But unfortunately, with the higher number of individuals involved in running has also come a greater number of resulting injuries. The most commonly reported running injury is a condition called patellofemoral pain syndrome (PFPS), which is essentially a general term for pain that develops behind or around the kneecap. There are several treatment strategies available for PFPS, but one of the newest methods showing some promise is gait retraining. This intervention is basically teaching someone how to run with a modified pattern by changing things like knee position or how the foot strikes the ground during a running stride. More specifically, runners that strike the ground with the backs of their feet first-which is called a rearfoot strike (RFS)-have been shown to have a greater risk of sustaining an injury than those who use a forefoot strike (FFS). Therefore, changing from a RFS to a FFS may reduce injuries in runners, but studies evaluating this are lacking. For this reason, a powerful study called a randomized-controlled trial (RCT) was conducted to determine if making this change could benefit runners with PFPS.



Recreational runners assessed one month after retraining


Recreational runners who were dealing with knee pain from PFPS and who also described themselves as having a RFS were recruited for the RCT. This search led to 16 runners being accepted into the study and then randomly assigned to either the experimental or control group. Participants in the experimental group went to eight sessions designed to retrain their gait. During each session, the participant would run on a treadmill facing a mirror while a trainer provided guidance to run on their toes or the balls of their feet. If necessary, additional instructions were given on how to accurately perform FFS running, and researchers confirmed that each participant eventually started using a FFS. The control group also attended eight sessions and performed the same exercises, but did not receive any instructions while running. All participants were evaluated before the retraining began, then immediately after it ended and one month later for knee pain and other measurements on the way their body moved.



Participants who changed their striking pattern experienced greater knee pain reductions


After the study was completed, participants in both groups reported less knee pain overall, but the reductions were much more significant and lasting in the experimental group after the gait retraining. Pain was measured using a tool called the visual analog scale (VAS), which has patients rate their pain on a scale from 0 to 10. In the control group, the average VAS score was a 4.3 at the beginning of the study, which dropped to a 2.9 immediately afterwards, and then increased again to 3.9 one month later. In the experimental group, the average score started at 5.3, then dropped to 1.0 and remained there one month later. This shows that not only did the experimental group runners experience less pain after gait retraining, but these improvements lasted for at least one month. Runners who are dealing with pain around the knee that may be due to PFPS may therefore benefit from changing their gait pattern to a forefoot strike if they aren't already running with this style. Physical therapists are movement experts that can help runners understand their gait pattern and offer suggestions on how to change it, and runners with knee pain are therefore encouraged to seek out their treatment to address these problems.



- As reported in the June '16 issue of Clinical Biomechanics
March 9, 2018