Short-term changes in running mechanics and foot strike pattern after introduction to minimalistic footwear.

BACKGROUND: Minimalistic footwear has garnered widespread interest in the running community, based largely on the premise that the footwear may reduce certain running-related injury risk factors through adaptations in running mechanics and foot strike pattern.

OBJECTIVE: To examine short-term adaptations in running mechanics among runners who typically run in conventional cushioned heel running shoes as they transition to minimalistic footwear.

DESIGN: A 2-week, prospective, observational study.

SETTING: A movement science laboratory.

PARTICIPANTS: Nineteen female runners with a rear foot strike (RFS) pattern who usually train in conventional running shoes.

METHODS: The participants trained for 20 minutes, 3 times per week for 2 weeks by using minimalistic footwear. Three-dimensional lower extremity running mechanics were analyzed before and after this 2-week period.

MAIN OUTCOME MEASUREMENTS: Hip, knee, and ankle joint kinematics at initial contact; step length; stance time; peak ankle joint moment and joint work; impact peak; vertical ground reaction force loading rate; and foot strike pattern preference were evaluated before and after the intervention.

RESULTS: The knee flexion angle at initial contact increased 3.8° (P < .01), but the ankle and hip flexion angles at initial contact did not change after training. No changes in ankle joint kinetics or running temporospatial parameters were observed. The majority of participants (71%), before the intervention, demonstrated an RFS pattern while running in minimalistic footwear. The proportion of runners with an RFS pattern did not decrease after 2 weeks (P = .25). Those runners who chose an RFS pattern in minimalistic shoes experienced a vertical loading rate that was 3 times greater than those who chose to run with a non-RFS pattern.

CONCLUSION: Few systematic changes in running mechanics were observed among participants after 2 weeks of training in minimalistic footwear. The majority of the participants continued to use an RFS pattern after training in minimalistic footwear, and these participants experienced higher vertical loading rates. Continued exposure to these greater loading rates may have detrimental effects over time.