SLR - October 2019 - Ellen I. Roberts
Reference: Hollander K, Liebl D, Meining S, Mattes K, Wilwacher S, Zech A. Adaptation of Running Biomechanics to Repeated Barefoot Running: A Randomized Controlled Trial. Am J Sports Med. 2019 Jul; 47 (8): 1975-1983Scientific Literature Review
Reviewed By: Ellen I. Roberts, DPM
Residency Program: Saint Vincent Hospital – Worcester, MA
Podiatric Relevance: Over the past decade, running barefoot to increase performance and decrease injury risk has been greatly debated. To date, there has been no clear evidence to confirm or refute this hypothesis. However, prior studies have shown that acutely transitioning to barefoot running alters running biomechanics, such as reduced ground-reaction forces and loading rates. Whether or not these effects still exist after only a short period of barefoot running has yet to be determined.
Methods: Sixty healthy, physically active participants between the ages of 18-35 participated in this study, half of which were randomly selected to a barefoot habituation group. The remaining participants were deemed the control group, all of whom wore cushioned footgear. The intervention for all participants consisted of 15 minutes of treadmill running at 70 percent of maximal oxygen consumption (VO2 max) per weekly session in the allocated footwear. Both before and after the eight-week intervention, a three-dimensional biomechanical analysis for each participant was conducted on an instrumental treadmill. Changes in kinematics, kinetics, and spatiotemporal parameters were then analyzed.
Results: From the 60 participants, a total of 53 completed the study. Acutely, running barefoot versus with footgear influenced foot strike index and ankle, foot, and knee angles at ground contact (P<.001). Other factors included vertical average loading rate (P=.003), peak force (P<.001), contact time (P<.001), flight time (P<.001), step length (P<.001), and also cadence (P<.001). There were no differences found in the average force (P=.391). After the 8 week study, barefoot participants were found to have a more anterior foot placement (P=.006), when running barefoot, whole no changes were observed in the footwear condition. Also, running barefoot increased the vertical average loading rates in both conditions and average vertical ground-reaction forces for running with shoe gear. Ankle, foot, and knee angles, ground contact, flight time, contact time, cadence and peak forces were relatively unchanged after the eight-week study.
Conclusions: Acutely changing to barefoot running induces several biomechanical changes. A reduction of loading rates in barefoot runners may be beneficial for the prevention of running-related injuries. In this study, however, an increase of loading rate was observed after habituation to barefoot running, which is contradictory to other studies on acute adaptations to barefoot running. Caution should be exercised when directly transferring short-term findings onto longer-term implications, such as reduction of injury risk.