- Heavily cushioned running shoes have become more popular, after several years in which minimalist shoes were common;
- The cushioned shoes are a response to discomfort or injuries sustained by runners in minimalist shoes;
- Biomechanical studies on the cushioned shoes reveals surprising data that forces might actually be higher in the cushioned shoes compared to standard shoes.
During the last year, many people switched their previous gym-based fitness to at-home fitness and what would also be called “old school” activities like outdoor running, walking, and cycling (and golf!).
There’s also been an interesting switch in the popularity of heavily padded or cushioned soles in running shoes. Relatively recently there was an emphasis on “minimalist” shoes which would supposedly promote a more natural running gait, but in the last year or so the pendulum has swung the other way. Heavily stacked and thickly cushioned running shoes are taking over.
You would think that the increased cushioning in the sole of these running shoes would lead to better shock absorption and reduced ground reaction force. But a few recent studies have actually found the opposite, that ground reaction forces are increased rather than decreased. What that means for a sore knee or hip remains to be seen, but the science is interesting.
The Maximalist Running Shoe
Personal story: I’ve had several surgeries on my right knee and have arthritis. As long as I stay within my limits I can run reasonably comfortably. I was intrigued a couple of years back with the research studies showing that peak ground reaction force might be reduced with minimalist shoes and a forefoot strike. I got some good shoes and ramped up very slowly from my old heel strike to a forefoot strike. Over the course of about 4 months my knee actually became more sore.
The experts would likely say that I had some sort of training error that led to the increased soreness, but from my view the only thing that mattered was that the problem I was looking to improve was made worse.
So back to the cushioned shoe I went, along with a return to my old heel strike pattern. And away went my knee pain.
The cushioned shoes typically have thick, foam-filled midsoles and are marketed as less likely to contribute to injuries.
What Does The Data Show?
Surprisingly, the few studies done in average recreational runners suggests that ground reaction forces are actually increased with the maximalist shoes.
One study published in 2018 showed an increased ground reaction force in 15 female runners with cushioned shoes, compared to average running shoes.
A later study allowed the runners to acclimate by running for 6 weeks in the cushioned shoes and again showed that the ground reaction force was high in spite of the training.
The data on ground reaction force is useful and counter-intuitive, but from my standpoint as an orthopaedic surgeon it doesn’t necessarily mean there will be increased knee pain. A particular runner’s cadence, foot strike pattern, body weight, and muscular strength will all influence how the joints feel.
So it seems there isn’t one “right” shoe type to best preserve joint health. Feel and comfort are very individual traits. If you’re interested in trying a different sole type I’d recommend you find a good local running shoe store, try running in a few types and ramp up your training very slowly.
By: Dev Mishra, M.D.
Founder and President, Sideline Sports Doc, Medical Director, Apeiron Life, Fellow-American Academy of Orthopaedic Surgeons, Institute For Joint Restoration, Menlo Park CA