A study conducted by The Hong Kong Polytechnic University recently found that novice distance runners running with softer footfalls can reduce the risk of injury by 62%.
Roy Cheung, Ph.D., associate professor of the department of rehabilitation sciences at The Hong Kong Polytechnic University, conducted a gait retraining program on injury prevention to investigate why running injuries have been on the rise.
According to a press release, this is the first randomized controlled trial to prove how modifying running posture with a systemic training method can prevent running injuries.
Cheung and his team collected data for a year on 320 novice runners who are 18 to 50 years old and who had less than two years of running experience and compared the results. Each of the runners run more than 8 km per week.
Of these 320 runners, 166 of them received two weeks of visual biofeedback training (the gait retraining group) in the lab during eight treadmill-training sessions. While on the laboratory treadmill, these runners were reminded via a monitor to run softer. The control group, the other 154 runners, didn’t receive any feedback while running on the treadmill in the lab. They ran their normal stride during the whole session.
Cheung and his team found that while on their own it was hard for runners to detect whether they are landing soft or hard, with the visual biofeedback training they were able to effectively change their gait when they were signaled to do so.
Before and after the gait retraining program, the researchers measured landing forces via the vertical average loading rate (VALR) and vertical instantaneous loading rate (VILR) of both groups at slow (8 km/h) and fast (12 km/h) paces. Both are biomechanical markers related to injury.
According to the data, the VALR and VILR in the gait retraining group was reduced after the retraining from 65.9 BW/s (body weight per second) to 54.8 BW/s and 90.7 BW/s to 75.0 BW/s at slow pace; and from 81.3 BW/s to 66.6 BW/s and 111.9 BW/s to 94.8 BW/s at fast pace. In the control group, no significant differences were found in VALR at slow pace after training, but VALR at fast pace and VILR at both testing speeds were slightly increased.
In the 12 month follow-up after the training session, the soft-stride runners reported 28 injuries, accounting for 16% in this group, much fewer than the 61 injuries (38%) of normal-stride runners. In total there was a 62% lower injury occurrence in soft-stride runners compared with the control group.
When broken down by types of injuries, soft-stride runners had 10 cases of Achilles tendinitis and calf strain while the control group didn’t have any of these types of injuries. In addition, the control group had 23 cases of plantar fasciitis and 18 cases of knee pain compared with 2 cases of plantar fasciitis and 4 cases of knee pain in the soft-stride runners.
“Many runners are unaware of their own gait in running. To prevent injuries, runners should land on midfoot; shorten stride length or increase step frequency; and slightly lean the body forward,” Cheung said in the release.
“The gait retraining group had a higher incidence of calf injury because there is a greater strain on the ankle plantar flexors when the participants attempted to soften their footfalls by using forefoot strike. Runners should use a midfoot strike pattern to avoid calf injury.”
