Walking in Minimalist Shoes Is Effective for Strengthening Foot Muscles

Introduction Weakness of foot muscles may contribute to a variety of loading related injuries. Supportive footwear may contribute to intrinsic foot muscle weakness by reducing the muscles' role in locomotion (e.g. absorbing forces and controlling motion). Increased stimulus to the foot muscles can be provided through a variety of mechanisms, including minimalist footwear and directed exercise. Purpose To determine the effect of walking in minimalist footwear or performing foot strengthening exercises on foot muscle size and strength. Results In study 1, genotype frequencies for ESR1 rs2234693 were significantly different between the injured and non-injured groups in a C-allele dominant (CC+CT vs. TT: odds ratio [OR] = 0.62, 95% confidence interval [CI] = 0.43–0.91) and additive (CC vs. CT vs. TT: OR = 0.70, 95% CI = 0.53–0.91) model in all athletes. In study 2, hamstring muscle stiffness was lower in subjects with the CC+CT genotype than in those with the TT genotype; a significant linear trend was found (r = 0.135, P = 0.029). In contrast, no associations were observed between ESR1 rs9340799 G/A and muscle injury or stiffness. Methods Fifty-seven runners were randomly assigned to one of three groups – minimalist shoe walking (MSW), foot strengthening exercise (FS), or control (C). All groups maintained their pre-study running mileage throughout the study. The MSW group walked in provided footwear, increasing weekly the number of steps/day taken in the shoes. The FS group performed a set of progressive resistance exercises at least 5 days/week. Foot muscle strength (via custom dynamometers) and size (via ultrasound) were measured at the beginning (week 0), middle (week 4), and end (week 8) of the study. Mixed model ANOVAs were run to determine if the interventions had differing effects on the groups. Key Terms Single nucleotide polymorphism; estrogen receptor; muscle stiffness; injury prediction; athletes Results There were significant group by time interactions for all muscle size and strength measurements. All muscle sizes and strength increased significantly from weeks 0-8 in the FS and MSW groups, while there were no changes in the C group. Some muscles increased in size by week 4 in the FS and MSW groups. Key Terms Single nucleotide polymorphism; estrogen receptor; muscle stiffness; injury prediction; athletes Conclusion Minimalist shoe walking is as effective as foot strengthening exercises in increasing in foot muscle size and strength. The convenience of changing footwear rather than performing specific exercises may result in greater compliance. Corresponding author: Sarah T. Ridge, 116B RB, Brigham Young University, Provo, UT 84602, (801) 422-1365, sarah_ridge@byu.edu The results of the present study do not constitute endorsement by the American College of Sports Medicine and are presented clearly, honestly, and without fabrication, falsification, or inappropriate data manipulation. Conflicts of Interest and Source of Funding: None Submitted for publication April 2018. Accepted for publication July 2018. © 2018 American College of Sports Medicine

from Sports Medicine via xlomafota13 on Inoreader https://ift.tt/2BfUghA
via IFTTT