Think twice before switching your sneaks. Changing to less cushioned running shoes could cause you to overexert certain parts of your legs and feet, says a new study in the Annals of Biomedical Engineering.
In an analysis of 19 runners, researchers at the University of Wisconsin-La Crosse found that those who landed on their forefoot experienced 11 percent more force on their Achilles each step compared to those who landed on their heel. That’s about 7,000 extra pounds of force over a mile for a 150-pound runner, researchers say.
What’s going on? The Achilles tendon and calf muscles take on a greater load with forefoot strikers than a heel strikers, who transfer more of their landing energy to muscles like the quadriceps, says study author John Willson, Ph.D. It’s not wrong to land this way—just a different force for each landing pattern.
Running barefoot or in minimalist shoes can lead you to land more on your forefoot, putting your Achilles and calf at some risk if they're weak. So the key is to transition gradually. Start with these tips from Nick Campitelli, D.P.M., a board-certified podiatrist in Akron, Ohio who runs drnicksrunningblog.com.
Follow The 10 Percent Rule
If you typically run 20 miles per week, designate a total of 2 miles to running in your minimal shoes, then build on that each week. Like slowly adding weight to your bench press, your body can respond to that 10 percent increase. “It might only be 3 minutes at the start of your run, then put your other shoes on and continue to run in those,” says Campitelli. But avoid adding those miles to the end of your run; your muscles are fatigued by then, making it hard to practice the new form properly.
You could try running a 5K after a few weeks, but you may be asking for trouble. “When I transitioned, I hit 10 miles after 6 to 8 months, and I still think that was too fast,” he says. If you're an aggressive heel striker, it could take several months up to a year to truly transition.
Monitor Your Pain
Lingering pain in your Achilles, the top of your foot, or lower calf is initially common because you’re using your foot differently. If pain goes away once you warm up during a run, you should be okay—it’s likely just normal running achiness. But if pain stays around all the time or worsens as you run, it could be something like a stress fracture, says Campitelli.
Strengthen Your Foot
Do 100 calf raises, which strengthen both calf and foot muscles, throughout the day. Concentrate on dispersing the weight on your entire forefoot, forming an arch and gripping the ground with your toes.
This article originally appeared in Men's Health US.