A parade of studies in recent years has been trampling the theory behind barefoot running. The latest of these comes from researchers here in Las Vegas at the American Academy of Orthopaedic Surgeons (AAOS).

One key notion behind barefoot and “minimalist” running is that they encourage the runner to strike the ground first with the balls of the feet. This allows the ankle and calf to absorb more of the impact from each footfall.

Today, researchers from the University of Kansas, plan to report that a significant number of experienced runners, age 30 and older (40 percent of men and 20 percent of women), maintained a heel-first running pattern even when running barefoot. That pattern naturally occurs when wearing a shoe with an elevated heel—even when running without shoes. Maintaining a heel-toe pattern while running barefoot or in a minimalist shoe may lead to more frequent injuries.

“Previous studies have demonstrated that an adolescent runner’s foot strike is heavily influenced by their running shoe,” said orthopaedic surgeon Scott Mullen, the lead author of the study in a press release. “Young runners quickly adapt to a forefoot strike pattern when running barefoot, whereas a heel strike is normally associated with wearing large-heeled training shoes.”

Older Runners Less Adaptable

Mullen and his colleagues measured the heel-to-toe drop of 26 runners, all age 30 or older with at least 10 years of running experience, when each ran in a traditional running shoe, and again when barefoot. They measured the heel and forefoot thickness at of the shoes at running speeds of 6, 7 and 8 miles per hour (mph) for women, and 7, 8 and 9 mph for men.

They used a motion capture system to analyze foot strikes.

Heel-to-toe thickness of the running shoe did not significantly correlate with a change in heel strike, nor did alterations in speed. Running barefoot resulted in a significant drop in percent heel strike at all speeds; however, 40 percent of the men and 20 percent of the women persisted with consistent strike patterns across all speeds with and without shoes.

“Our study indicates that older runners (age 30 and older) are not able to adapt as quickly to running barefoot,” said Mullen. “The inability to adapt the foot strike to the change in shoe type may put these runners at increased risk of injury. Older runners should be cautious when transitioning to a more minimalist type of shoe.”

I’ll go along with these conclusions, especially since other studies have shown that many people don’t know which part of their foot strikes the ground first.

Actually everyone should be cautious making the transition, because even if you get it right, it takes a long time to adapt to a forefoot strike,  and it can be tiring on your calf and Achilles tendon.

But I’ll also say, I’m really glad I made the switch. At age 51.