Athletes have been training barefoot on grass fields and sand for years. Why?

By Josh Staph

Theory says that without the support of athletic shoes, the bare foot is forced to use muscles it otherwise wouldn’t. Many believe such training strengthens the lower body and prevents injuries. To gain a full understanding of this practice, we spoke to training experts, Eric Lichter and Tim Robertson, co-owners of Speed Strength Systems, Cleveland, Ohio.

Lichter and Robertson have implemented barefoot training with their athletes, including NFL prospect Donte Whitner and NFL stars London Fletcher, Nate Clements, Tony Fisher and LeCharles Bentley. “We perform all kinds of speed and agility work in our sandpit to help strengthen our athletes’ feet, ankles, knees and hips,” Lichter says.

Taking the practice to solid ground, Speed Strength’s clients now perform dynamic speed warm-up drills without shoes. Lichter says, “When you wear shoes, you lose some of the force production of your feet. When we have the athletes warm up barefoot, their feet produce more force, which makes them stronger, faster and more powerful.”

Nike’s research

In June 2002, Nike set out to test the practice that was keeping its shoes off world-class athletes’ feet. Senior researcher Jeff Pisciotta set up a Nike Sports Research Lab (NSRL) on a grass soccer field. Ten men and ten women ran at a 7:30-mile pace with pressure-measuring insoles taped to the bottom of their bare feet. Simultaneously, high-speed cameras captured the 40 feet in action so that researchers could later examine joint angles, foot motion and foot pressures.

According to their research, a foot sans shoe makes more natural contact with the ground. Without confinement, the foot moves freely, pressure is evenly dispersed among the foot bones and toe muscles contract to grip the ground—incorporating more muscles throughout the rest of the body. Pisciotta concluded that a bare foot works harder and more naturally than one shod in a running shoe, supporting the belief that training barefoot can improve strength, speed and agility.

The practice does have its limitations, however. A bare foot lacks protection and cushioning, so a well-groomed surface is necessary. Also, the bottom of the foot has little traction, making speed and agility training difficult.

Their technology

To combat these problems, Nike developed its Free Technology. Nike points out that the Free’s essence is flexibility, which is derived from a sliced soft upper material and a segmented sole. Each cut is positioned to reflect the pressure measurements taken at the NSRL, as well as the foot’s skeletal structure. In contrast to most athletic shoes, which control the shape of the foot, where force is distributed, and how foot contact is made, Nike says your feet control the Free.

Different versions of the Free are available. On a scale where the typical athletic shoe is on one end and barefoot training on the other, the 5.0 falls right between, while the 4.0 provides slightly more freedom. The Free Trainer—designed for change-of-direction training—has a Velcro strap across the forefoot to provide lateral stability during speed and agility drills.