Effect of metatarsal phalangeal joint extension on plantar soft tissue stiffness and thickness

Garcia, Christopher A.<sup>1</sup>; Hoffman, Shannon L.<sup>1</sup>; Hastings, Mary K.<sup>1</sup>; Klaesner, Joseph W.<sup>1</sup>; Mueller, Michael J.<sup>1</sup>

Affiliations

¹Program in Physical Therapy, Washington University School of Medicine, Campus Box 8502, 4444 Forest Park Boulevard, St. Louis, MO 63108-2212, USA

Abstract and keywords

Background: Plantar soft tissue stiffness and thickness are important biomechanical variables to understand stress concentrations that may contribute to tissue injury.

Objective: The purpose of this study was to determine the effects of passive metatarsal phalangeal joint (MPJ) extension on plantar soft tissue stiffness and thickness.

Methods: Seventeen healthy participants (7 male, 10 female, mean age 25.3 years, S.D. 4.4 years, mean BMI 24.7 kg/m², S.D. 3.2 kg/m²) were tested. Plantar soft tissue stiffness and thickness were measured at the metatarsal heads, midfoot and heel using a custom-built indentor device and an ultrasound machine.

Results: Indicators of soft tissue stiffness (K₁ values) at the metatarsal heads and midfoot showed increases in stiffness of 81–88% (S.D. 20–33%) in the MPJ extension position compared with the MPJ neutral position. Soft tissue thickness measures at the metatarsal heads with the MPJ in neutral ranged from a mean of 8.9 to 13.5 mm and decreased, on average, by 8.8% (S.D. 2.9%) with MPJ extension.

Conclusions: MPJ extension has a profound effect on increasing forefoot plantar soft tissue stiffness and a consistent but minimal effect on reducing soft tissue thickness. These changes may help transform the foot into a rigid lever at push-off consistent with the theory of the windlass mechanism.

Keywords: Windlass mechanism; Material properties; Plantar tissue; Soft tissue thickness; Soft tissue stiffness; Plantar fascia

Links

DOI: 10.1016/j.foot.2007.12.002

PubMed: 19492011

History

Received: 2007-05-23

Revised: 2007-09-27

Accepted: 2007-12-20

Online: 2008-03-14

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Cited By (2)

Year	Entry
2010	Kwan RL-C, Zheng Y-P, Cheing GL-Y. The effect of aging on the biomechanical properties of plantar soft tissues. Clin Biomech (Bristol, Avon). 2010;25(6):601-605.
2011	Chen W-M, Shim VP-W, Park S-B, Lee T. An instrumented tissue tester for measuring soft tissue property under the metatarsal heads in relation to metatarsophalangeal joint angle. J Biomech. June 3, 2011;44(9):1801-1804.