You’ve seen ’em in the gym and on late-night commercials: Gadgets that promise to make you bigger, stronger, faster.
When Javier Ibarra, Derek Oldroyd, and Ryan Zane, then students in UNLV’s physical therapy program, spotted an unusual type of shoe on fellow weightlifters in the gym, they couldn’t help but wonder about them. All three are recreation lifters and had noticed the shoes primarily on people performing barbell back squats. Their curiosity led to questioning the shoe’s marketing claims.
“Once I found out it’s a heel-lifted shoe, I started reading posts about them on weightlifting forums,” Zane said. “Several people wrote that they bought the shoes because they were designed to help the body maintain a more upright posture during squats, thereby reducing the risks for lower back pain and injuries. Others stated the shoes made squats more effective by focusing the effort to the legs. Then I saw ads with similar claims.”
The shoes are very rigid with a heel lift of about 1.5 inches. “They don’t seem ideal for other exercises, and cost about $200,” Zane said. “So why would people invest that much money just to do squats?”
Zane, Ibarra, and Oldroyd (all ’16 Doctor of Physical Therapy) approached physical therapy professors Szu-Ping Lee and Carrie Gillis with the research idea of testing the shoes. They conducted their study through their second and third years in the physical therapy doctoral program.
To test the shoes, the research team used a 3D motion capture system and an electrogoniometer to monitor the motion of the thoracic spine, lumbar spine, and knee. They also used electromyography to measure the activity levels of the back and leg (quadriceps) muscles during the up and down phases of the squat.
“We created three situations for the squats during which the lifter would drop to a depth where the hip was at least at the same level to the knee. We wanted 80 percent of the lifter’s maximum effort to simulate a typical squat training,” Lee explained.
For the control condition, participants performed the exercise barefoot while standing on a flat surface. They repeated the exercise on a surface with a 4.3-degree downward angle to match the slope of the shoes. Finally, the participants performed the squats with the heel-lifted shoes.
“During each situation, we measured and evaluated trunk position, as well as muscle activation levels. When we compared the results, heel-raised foot postures do not significantly affect spinal and knee extensor muscle activations, nor trunk and knee movements,” Lee said. “We concluded heel-raised weightlifting shoes are unlikely to provide significant protection against back injuries for recreational weightlifters during the barbell back squat.”
Lee made one caveat to the study’s findings.
“Although the shoes’ performances did not match the claims, they could be helpful to a very small set of individuals who have an especially low range of ankle motion that prevents them from completing a deep squat,” Lee said. “The shoes’ stiff construction may provide some marginal benefits. But for most recreational lifters, the shoes offer no significant training or injury-prevention benefits.”
The study’s findings appeared in the March issue of the Journal of Strength and Conditioning Research.