Effects of foot core strengthening on running foot biomechanics: a randomized controlled trial

Author(s)

Alessandra Bento Matias

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina (FM/SBD)
• Defense date: 2021-12-14

Examining board members

Isabel de Camargo Neves Sacco; Marcos Duarte; Renan Alves Resende; Paulo Roberto Pereira Santiago

• Advisor: Isabel de Camargo Neves Sacco

Abstract

Running is one of the most popular physical activities, however, running-related injuries are highly prevalent and can lead to discontinuation of practice. The etiology of the injuries is multifactorial and mechanical loads and biomechanical aspects of the lower limbs seem to be associated with these injuries. The foot is the first segment to interact with the ground and any change in its structure, function or landing can alter the mechanics of the remainder of the lower limb. Depending on the type of the footstrike pattern (rearfoot, forefoot and midfoot), the longitudinal arch absorbs and stores the loads received as energy differently, relying on a complex structure that is maintained by the intrinsic and extrinsic muscles, ligaments, and plantar aponeurosis. Given the crucial role of the foot in running, this thesis aimed to explore the biomechanical aspects of the foot during running and, to investigate, through a randomized controlled clinical trial, the effectiveness of an innovative foot-core strengthening program of 8 weeks on foot-ankle kinematics and impact forces during running in recreational long-distance runners. Prior to this clinical trial, we developed further studies to better understand the biomechanics of the foot at different running footstrike patterns and assessed the usability and reliability of the multisegment foot model. The first step in the construction of this thesis was the development of a foot exercises program and the conception and design of the randomized controlled clinical trial protocol. The second step of this thesis was to assess the reliability, usability, and accuracy of the measurements of the multisegment foot model during running, which are an important outcome of the clinical trial. We conclude that the inter-examiner repeatability of the foot model is lower in running than in walking. We proposed and tested a new configuration of the skin marker-based multi-segment foot model for the evaluation of the medial longitudinal arch (MLA). We found that this new proposition had a lower reliability compared to the original configuration, but the variability of all angles with 3D projections was always smaller than the variability of 2D projections. We also assessed the correlation and accuracy of the variations and of the new proposition of the skin-marker based measures of MLA deformation with respect to standard clinical radiographic measures, used as reference. We found that the new proposition using the navicular tuberosity as the MLA vertex provided the most accurate estimate of the MLA when compared to radiographic measurements. The third step of this thesis investigated how the type of footstrike pattern (forefoot or rearfoot) would influence the foot biomechanics during running. It was found that the way the foot interact with the ground determines the kinematic behavior of the rest of the foot segments during stance phase. We were surprised to find that the first peak of the vertical force and the load rates in some forefoot runners were similar to those in rearfoot runners. In the last step of this thesis, we concluded that the physical therapy intervention was effective in modifying the kinematic patterns of the ankle, tarso-metarsal, midtarsal and metatarso-phalangeal joints; as well as some biomechanical risk factors for running injuries, such as the MLA movement and the rearfoot angle; but there was no effect on running impact forces and load rate. The observed changes in foot joint kinematics may be responsible for the reduction in running-related injuries incidence following the foot-core training program in recreational runners (AU)

• FAPESP's process: 16/17077-4 - Effects of a foot and ankle complex strengthening program on the occurrence of injuries and biomechanics in long distance runners: a controlled, randomized clinical trial
• Grantee: Alessandra Bento Matias
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)