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Wallace, Ian

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Wallace

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Wallace, Ian

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2015 - 20183

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Author's Publications: search.filters.isAuthorOfPublication.f341cf20-7b8b-4e5a-800f-b99709368b04

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Now showing 1 - 3 of 3
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    Heel impact forces during barefoot versus minimally shod walking among Tarahumara subsistence farmers and urban Americans
    (The Royal Society Publishing, 2018) Wallace, Ian; Koch, Elizabeth; Holowka, Nicholas; Lieberman, Daniel
    Despite substantial recent interest in walking barefoot and in minimal footwear, little is known about potential differences in walking biomechanics when unshod versus minimally shod. To test the hypothesis that heel impact forces are similar during barefoot and minimally shod walking, we analysed ground reaction forces recorded in both conditions with a pedography platform among indigenous subsistence farmers, the Tarahumara of Mexico, who habitually wear minimal sandals, as well as among urban Americans wearing commercially available minimal sandals. Among both the Tarahumara (n = 35) and Americans (n = 30), impact peaks generated in sandals had significantly (p < 0.05) higher force magnitudes, slower loading rates and larger vertical impulses than during barefoot walking. These kinetic differences were partly due to individuals' significantly greater effective mass when walking in sandals. Our results indicate that, in general, people tread more lightly when walking barefoot than in minimal footwear. Further research is needed to test if the variations in impact peaks generated by walking barefoot or in minimal shoes have consequences for musculoskeletal health.
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    Foot strength and stiffness are related to footwear use in a comparison of minimally- vs. conventionally-shod populations
    (Nature Publishing Group UK, 2018) Holowka, Nicholas; Wallace, Ian; Lieberman, Daniel
    The longitudinal arch (LA) helps stiffen the foot during walking, but many people in developed countries suffer from flat foot, a condition characterized by reduced LA stiffness that can impair gait. Studies have found this condition is rare in people who are habitually barefoot or wear minimal shoes compared to people who wear conventional modern shoes, but the basis for this difference remains unknown. Here we test the hypothesis that the use of shoes with features that restrict foot motion (e.g. arch supports, toe boxes) is associated with weaker foot muscles and reduced foot stiffness. We collected data from minimally-shod men from northwestern Mexico and men from urban/suburban areas in the United States who wear ‘conventional’ shoes. We measured dynamic LA stiffness during walking using kinematic and kinetic data, and the cross-sectional areas of three intrinsic foot muscles using ultrasound. Compared to conventionally-shod individuals, minimally-shod individuals had higher and stiffer LAs, and larger abductor hallucis and abductor digiti minimi muscles. Additionally, abductor hallucis size was positively associated with LA stiffness during walking. Our results suggest that use of conventional modern shoes is associated with weaker intrinsic foot muscles that may predispose individuals to reduced foot stiffness and potentially flat foot.
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    Publication
    Osteoporosis
    (Oxford University Press, 2015) Wallace, Ian; Rubin, Clinton T.; Lieberman, Daniel