Running barefoot leads to lower running stability compared to shod running - results from a randomized controlled study

Local dynamic running stability is the ability of a dynamic system to compensate for small perturbations during running. While the immediate effects of footwear on running biomechanics are frequently investigated, no research has studied the long-term effects of barefoot vs. shod running on local dynamic running stability. In this randomized single-blinded controlled trial, young adults novice to barefoot running were randomly allocated to a barefoot or a cushioned footwear running group. Over an 8-week-period, both groups performed a weekly 15-min treadmill running intervention in the allocated condition at 70% of their VO2 max velocity. During each session, an inertial measurement unit on the tibia recorded kinematic data (angular velocity) which was used to determine the short-time largest Lyapunov exponents as a measure of local dynamic running stability. One hundred running gait cycles at the beginning, middle, and end of each running session were analysed using one mixed linear multilevel random intercept model. Of the 41 included participants (48.8% females), 37 completed the study (drop-out = 9.7%). Participants in the barefoot running group exhibited lower running stability than in the shod running group (p = 0.037) with no changes during the intervention period (p = 0.997). Within a single session, running stability decreased over the course of the 15-min run (p = 0.012) without differences between both groups (p = 0.060). Changing from shod to barefoot running reduces running stability not only in the acute phase but also in the longer term. While running stability is a relatively new concept, it enables further insight into the biomechanical influence of footwear.

Preliminary Evidence That Taping Does Not Optimize Joint Coupling of the Foot and Ankle Joints in Patients with Chronic Ankle Instability

Background: Foot–ankle motion is affected by chronic ankle instability (CAI) in terms of altered kinematics. This study focuses on multisegmental foot–ankle motion and joint coupling in barefoot and taped CAI patients during the three subphases of stance at running. Methods: Foot segmental motion data of 12 controls and 15 CAI participants during running with a heel strike pattern were collected through gait analysis. CAI participants performed running trials in three conditions: barefoot running, and running with high-dye and low-dye taping. Dependent variables were the range of motion (RoM) occurring at the different inter-segment angles as well as the cross-correlation coefficients between predetermined segments. Results: There were no significant RoM differences for barefoot running between CAI patients and controls. In taped conditions, the first two subphases only showed RoM changes at the midfoot without apparent RoM reduction compared to the barefoot CAI condition. In the last subphase there was limited RoM reduction at the mid- and rearfoot. Cross-correlation coefficients highlighted a tendency towards weaker joint coupling in the barefoot CAI condition compared to the controls. Joint coupling within the taped CAI conditions did not show optimization compared to the barefoot CAI condition. Conclusions: RoM was not significantly changed for barefoot running between CAI patients and controls. In taped conditions, there was no distinct tendency towards lower mean RoM values due to the mechanical restraints of taping. Joint coupling in CAI patients was not optimized by taping.

BIOMECHANICS OF SHOD AND BAREFOOT RUNNING: A LITERATURE REVIEW

ABSTRACT This study aims to analyze and summarize the biomechanical (kinematics, kinetics and neuromuscular) differences between shod and barefoot running, through a literature review. Searches were conducted for complete articles published between 2013 and November 2018 in the Web of Science, PubMed, Scopus and SPORTdiscus databases. The search terms used were Biomechanics, Kinetics, Kinematics, Electromyography, “Surface Electromyography”; and Unshod, Barefoot, Barefeet and Running. The search resulted in 687 articles; after excluding duplicates and selecting by title, abstract and full text, 40 articles were included in the review. The results show that there are important differences in the biomechanics of running when shod or barefoot. In general, studies indicate that in barefoot running: a) individuals present forefoot or midfoot foot strike patterns, while in shod running the typical pattern is the rearfoot strike; (b) greater cadence and shorter stride length are observed; and (c) there is greater knee flexion, lower peak vertical ground reaction force and greater activation of the medial gastrocnemius. In addition, barefoot runners contact the ground with greater plantar flexion, possibly as a strategy to reduce impact when stepping without footwear. These differences, as well as runners’ individual characteristics, should be considered in the prescription of the barefoot running, in order to minimize injuries resulting from the practice. Level of Evidence II; Review.