Biomechanics of Running In Various Conditions

Barefoot running has become increasingly popular. Many runners turn to minimalist footwear in the hope of mimicking barefoot running, but with more protection. But is running in minimalist shoes biomechanically similar to going barefoot?

No, say researchers from various Australian universities.

The scientists enlisted the help of 22 highly trained runners and put them through several running protocols: barefoot; minimalist (Nike® Free 3.0, with 4-millimeter heel-forefoot offset); lightweight racing flat (Nike Lunaracer2, with 6 mm heel-forefoot offset); and “regular” (whatever more traditional running shoe each participant was currently using).

Subjects were given a familiarization period in which to adapt to the various conditions. During the trial, the runners kept pace with 90% of their best 10-kilometer time from the previous year. To observe biomechanics and kinematics, the researchers put markers on the runners’ hips, legs and feet. Each participant averaged about 10 trials per condition.

Here are some highlights from the findings:

• Stride length was shortest and stride
  frequency was highest when runners
  were barefoot.
• Stride length was shorter and stride frequency was higher in the minimalist and racing-flat conditions than in the regular protocol. Stride length and frequency
  were similar for minimalist and racing-
  flat shoes.
• Peak knee flexion during midstance was less during barefoot running than during shod conditions. No differences were found between shod conditions.
• Peak knee extension was less during barefoot running than during shod conditions. No differences were found between shod conditions.
• When barefoot, runners experienced less dorsiflexion at initial contact and more
  plantar flexion at toe-off than they did
  when shod.

The authors conceded that the study had limitations. First, all participants were habitually shod runners. Second, the minimalist shoes were cushioned with
an elevated heel.

Despite these points, the authors urged
caution when transitioning from shod training conditions to barefoot running, owing to the increased work required at the ankle.

“Conversely, the reduction in joint moments and work done at the knee while running barefoot may provide potential benefits for the management of knee pain and injury,” they added.

The study was published in the British Journal of Sports Medicine (2013; 47, 387–92).