La Trobe
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Foot posture influences the electromyographic activity of selected lower limb muscles during gait

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journal contribution
posted on 28.05.2021, 02:06 by George MurleyGeorge Murley, Hylton MenzHylton Menz, Karl LandorfKarl Landorf
Background: Some studies have found that flat-arched foot posture is related to altered lower limb muscle function compared to normal- or high-arched feet. However, the results from these studies were based on highly selected populations such as those with rheumatoid arthritis. Therefore, the objective of this study was to compare lower limb muscle function of normal and flat-arched feet in people without pain or disease.Methods: Sixty adults aged 18 to 47 years were recruited to this study. Of these, 30 had normal-arched feet (15 male and 15 female) and 30 had flat-arched feet (15 male and 15 female). Foot posture was classified using two clinical measurements (the arch index and navicular height) and four skeletal alignment measurements from weightbearing foot x-rays. Intramuscular fine-wire electrodes were inserted into tibialis posterior and peroneus longus under ultrasound guidance, and surface EMG activity was recorded from tibialis anterior and medial gastrocnemius while participants walked barefoot at their self-selected comfortable walking speed. Time of peak amplitude, peak and root mean square (RMS) amplitude were assessed from stance phase EMG data. Independent samples t-tests were performed to assess for significant differences between the normal- and flat-arched foot posture groups.Results: During contact phase, the flat-arched group exhibited increased activity of tibialis anterior (peak amplitude; 65 versus 46% of maximum voluntary isometric contraction) and decreased activity of peroneus longus (peak amplitude; 24 versus 37% of maximum voluntary isometric contraction). During midstance/propulsion, the flat-arched group exhibited increased activity of tibialis posterior (peak amplitude; 86 versus 60% of maximum voluntary isometric contraction) and decreased activity of peroneus longus (RMS amplitude; 25 versus 39% of maximum voluntary isometric contraction). Effect sizes for these significant findings ranged from 0.48 to 1.3, representing moderate to large differences in muscle activity between normal-arched and flat-arched feet.Conclusion: Differences in muscle activity in people with flat-arched feet may reflect neuromuscular compensation to reduce overload of the medial longitudinal arch. Further research is required to determine whether these differences in muscle function are associated with injury. © 2009 Murley et al; licensee BioMed Central Ltd.

Funding

This project was supported by a research grant from the Australian Podiatry Education and Research Foundation (APERF). We thank Mark Whiteside, Lisa Scott and Bianca David for assisting with participant recruitment and testing; and Southern Cross Medical Imaging at La Trobe University Medical Centre. We also thank Monika Buljan and Paul Kabaila (La Trobe University) for statistical support relating to this study. HBM is currently a National Health and Medical Research Council fellow (Clinical Career Development Award, ID: 433049).

History

Publication Date

26/11/2009

Journal

Journal of Foot and Ankle Research

Volume

2

Issue

1

Article Number

ARTN 35

Pagination

9p.

Publisher

BIOMED CENTRAL LTD

ISSN

1757-1146

Rights Statement

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