Christine Pollard has made it her mission to better understand how to help runners prevent injury and find their ideal running shoe.
“With my background as a physical therapist, my focus has always been lower-extremity injury and how to prevent it,” the kinesiology associate professor says. “While there are many factors that lead to injury, one of them is footwear. Really understanding how footwear influences biomechanics is critical because it’s a tool we can use to actually help prevent injury.”
Christine’s fascination with footwear biomechanics began with her doctoral studies and has been renewed with dramatic changes in running shoes in the last 10 years. When she was pursuing her PhD, minimal and maximal running shoes did not exist.
“In traditional running shoes there is typically more cushioning under the heel than under the toe,” Christine says. “In minimal shoes, there is nearly no cushioning, and with maximal shoes the cushioning is spread evenly across the shoe.”
While maximal running shoes have been on the market since 2009, only recently have they gained traction.
“The minimal shoes really took off — and then they got less popular as people got more injuries. People were running in these shoes as if they still had cushioning, and this caused a lot of injuries.”
Christine says around 2014 there was a decline in minimal shoe sales and use, and an increased interest in maximal shoes. With their rise in popularity, Christine started asking questions.
Her study, published in The Orthopedic Journal of Sports Medicine in June, is the first research publication to evaluate maximal running shoes.
“Minimal shoes have been researched, and we know more biomechanically about what they’re doing,” Christine says. “The main goal of this study was to understand the influence of a maximal shoe on running biomechanics as it relates to risk for injury.”
Christine and JJ Hannigan, a post-doctoral researcher, enlisted 15 runners from central Oregon to participate in the study conducted at OSU-Cascades’ Functional Orthopedic Research Center of Excellence (FORCE) Lab.
Christine and JJ wanted to determine if the extra cushioning in maximal shoes decreased the force in which runners strike the ground. As 90 percent of runners in the United States are heel strikers (their heel strikes the ground first), all participants were screened for this running style.
To evaluate the difference between the Hoka One One, the first maximal shoe to market, and traditional shoes, each runner ran a 5K in new Hoka Bondi 4 shoes and in traditional shoes a few days later. None of the runners had previously run in a Hoka shoe.
“We thought if you put more cushioning under their foot, we’d see lower impact peak and lower loading rate, but in fact what we found was the opposite,” Christine says. “The impact peak was higher and the loading rate was higher. So, the two things associated with an increased risk of injury went up when they ran in the Hoka shoes.”
The researchers now want to determine if runners strike harder because of the extra cushioning or if the results were indeed related to more cushioning. These questions are leading them into their next study.
With the FORCE Lab, Christine is determined to better understand how footwear influences running biomechanics and how to help prevent lower extremity injury. In addition to the follow-up Hoka study, she has two related studies underway.
“With these new options, people really want to know if they’re running in the right shoe,” Christine says. “My take-home message is that if you aren’t having pain or injury and are happy with your performance, stick with what you’re using. But if you are having pain, then it’s time to have a full assessment to examine intrinsic risk factors, such as strength, range of motion and structure as well as extrinsic risk factors, such as footwear and training.”