The latest study to weigh barefoot running against traditional running shoes finds that mixing up the footwear -- training in cushioned shoes, competing in track flats -- may confuse the running gait in young athletes.

While running seems a fairly straightforward activity, ask a devotee his or her opinion about foot strike -- is it better to land on your forefoot (as barefoot running shoes promote) or heel? -- and you're likely to stir up some hot debate.

To add more fuel to the fire, researchers from the University of Kansas recruited 12 adolescent competitive athletes from local track teams, and asked them to run on a treadmill in cushioned heel trainers, track flats, and without any shoes at four different speeds. Researchers measured a battery of biomechanical details, such as stride length and foot strike, with a motion capture system.

"Running barefoot or running in less of a running shoe is a newer trend," says Dr. Scott Mullen, an orthopedic surgeon at The University of Kansas Hospital. "What we were trying to evaluate is whether or not the foot strike would change in an adolescent -- who doesn't yet have a permanently established gate -- when they changed their shoe or running speed."

The researchers found that shoe type "dramatically" altered running biomechanics in the young runners. When wearing cushioned heel trainers, the athletes landed on their heel nearly 70 percent of the time at all speeds. With the track flats, the heel hit the ground first less than 35 percent of the time; and when barefoot, less than 30 percent of the time.

"What we found is that simply by changing their footwear, the runners' foot strike would change," says Dr. Mullen. "When they ran in the cushioned heel or an average running shoe ─ even when running a five-minute mile ─ the athletes landed on their heel first."

Many adolescent runners train in cushioned heels but compete in track spikes, which may give them less of a performance advantage during competition, he says.

Mullen presented his research Tuesday at the 2013 Annual Meeting of the American Academy of Orthopaedic Surgeons in Chicago.