In last week’s blog post, I discussed utilized real-time sound-feedback as a means to minimize impact forces while running.
This will I’ll be discussing a very popular topic in running circles; the influence of a shoe’s heel-to-toe drop and associated injury risk.
Throughout my seven years of college, I worked at a specialty running store, Fleet Feet Sports Augusta. During that time, minimal running shoes became very popular. I’ve seen all sorts of brand propaganda and online running gurus discuss how minimal shoes can reduce injury risk.
I love running shoes. And I believe a comfortable running shoe can play a role in injury prevention. But I was never a big believer in a certain type of shoe drop could really change injury risk all that much. At that time, I wasn’t aware of much research to confirm or deny that theory. Thankfully, we have research that investigates that very idea of whether differences in heel-to-toe drop can alter injury risk.
This study was published in 2016 in The American Journal of Sports Medicine. You can read the abstract below.
Type of Study
This study was a randomized control trial. This type of study is considered among the higher levels of research because the participants are blinded to which group they are in. This helps to minimize the placebo effect.
553 recreational runners were included in the final analysis.
Each participant was randomized to run in either a 10mm drop shoe, 6mm drop shoe, or a 0mm drop shoe. The actual cushioning level of the shoes were similar throughout. This means that the 0mm shoe was roughly the same overall height off the ground as the 10mm drop shoe and, therefore, had a comparable amount of overall cushion.
Additionally, the participants were also divided based on their regularity of running over the previous year. They were classified as occasional runners if they had been running or less than 6 months and regular runners if they had been running for greater than 6 months.
These runners were followed for 6 months and were asked to report any running-related injury.
Of the 553 runners, 136 participants were injured. The percentage of injured runners, in each group, is listed below:
- 10mm drop group- 21.6%
- 6mm drop group- 27.4%
- 0mm drop group- 24.6%
Based on a statistical analysis, called an adjusted Cox regression analysis, none of the different minimal shoe heel-to-toe drops (6mm and 0mm) were associated with decreased injury risk compared to 10mm heel-to-toe drop group.
Also, when looking at those who had been running for greater than 6 months, lower heel-to-toe drop shoes were associated with greater injury risk compared to those running less than 6 months.
Based on previous research, shoes with different heel-to-toe drops were associated with varying ground reaction forces and joint angles. This could potentially lead to differences in associated injury risk, between shoes with varying heel-to-toe drops, but the results of this study did not support that theory.
Additionally, the authors concluded that injury risk with lower heel-to-toe drop shoes could be population-specific. Based on the results of this study, it appears safer to recommend lower heel-to-toe drop running shoes in those who are less experienced runners. It could be speculated, that with a more experienced runner, the transition to a minimal type shoe was not gradual enough.
I thought this was such a great study. I thought it was great they used very similar shoes, in terms of actual cushion, when comparing the different heel-to-toe drops.
I didn’t particularly like how the differences in occasional and regular runners were grouped. I really wish they would have divided them by lower and higher mileage. Because someone could be an occasional runner (running less than 6 months over the past year by this study’s definition) and still be running 40 miles a week. And a regular runner (running for greater than 6 months over the previous year by this study’s definition) could be running 6 miles a week. I’m sure they’d be some drawback to analyzing this based on mileage as well though. Research is insanely difficult to conduct. And it’s much easier to be a critic, on a blog post, than it is to conduct research.
I think this study helps to adjust the focus, of utilizing running shoes to minimize injury risk, away from comparing minimal and traditional running shoes. Because this study, which is the best of its kind to compare injury risk (to my knowledge) between heel-to-toe drop shoes, doesn’t support that it makes a significant difference.
I always suggest that runners go to a specialty running shoe and get fitted. Not so much for determining the ‘right’ type of running shoes (based on things like pronation, level of cushioning, arch type, heel-to-toe drop, etc) but more to get an appropriate size and have a large variety of shoes to choose from.
As I discussed in a previous post, alternating running shoes has been associated with decreased injury risk. In my opinion, it may be beneficial to alternate shoes with different heel-to-toe drops due to previous research supporting varying joint angles and ground reaction forces while running in them. Not so much because one is better than the other. But because they are different.
Questions for Readers
Have you ever found success in reducing injury risk when using either a lower or higher heel-to-drop shoe?
Have you experimented with alternating between a minimal shoe and traditional running shoe?