Elsevier

Gait & Posture

Volume 41, Issue 2, February 2015, Pages 395-401
Gait & Posture

Increased unilateral foot pronation affects lower limbs and pelvic biomechanics during walking

https://doi.org/10.1016/j.gaitpost.2014.10.025Get rights and content

Highlights

  • Foot pronation increases shank and femur internal rotation during gait.

  • Foot pronation reduces knee and hip internal rotation moment during gait.

  • Unilateral foot pronation increases pelvic ipsilateral drop during gait.

  • Foot pronation increases hip and knee adduction moments on the contralateral side.

Abstract

Background

Increased unilateral foot pronation may cause biomechanical changes on the lower limbs during gait. We investigated the effects of increased unilateral foot pronation on the biomechanics of lower limbs and pelvis during gait.

Methods

Kinematic and kinetic data of 22 participants were collected while they walked wearing flat and laterally wedged sandals. Principal omponent analysis was used to compare differences between conditions.

Findings

Wearing the wedged sandal on the ipsilateral side increased ankle eversion moment (p < 0.001; effect size = 0.97); rearfoot eversion angle (p < 0.001; effect size = 0.76); shank internal rotation (p = 0.009; effect size = 0.53); increased and reduced knee internal rotation angle during early and late stance, respectively (p < 0.001; effect size = 0.89); increased femur internal rotation (p = 0.005; effect size = 0.90); reduced hip internal rotation moment during late stance (p = 0.001; effect size = 0.68); and increased pelvic ipsilateral drop (p = 0.02; effect size = 0.48) of the ipsilateral side. Wearing the wedged sandal on the contralateral side increased pelvic contralateral drop (p = 0.001; effect size = 0.63); hip adduction moment throughout stance (p = 0.027; effect size = 0.46); and increased and reduced the knee adduction moment in early and late stance, respectively (p < 0.001; effect size = 0.79).

Interpretation

The increased lower limb internal rotation caused by the wedged sandal reinforces the assumption that rearfoot eversion is coupled with shank internal rotation. The increased pelvic contralateral drop caused by the wedged sandal on the contralateral side may explain the increased hip and knee adduction moments on the ipsilateral side. Increased unilateral foot pronation causes biomechanical changes on both lower limbs that are associated with the occurrence of injuries.

Introduction

Increased foot pronation causes biomechanical changes at the lower limbs, which may result in musculoskeletal injuries at the proximal joints [1], [2]. Previous study had shown that inadequate forefoot alignment at ground contact could produce large pronation torques that result in increased magnitude and duration of pronation during walking [3]. Following this rationale, Souza et al. [4] demonstrated that walking using lateral wedges under the forefoot increases rearfoot eversion and shank and hip internal rotation angles during the stance phase. Our work builds on these insights by examining the effects of increased unilateral foot pronation on knee and hip transverse plane moments and pelvic kinematics, since previous studies have demonstrated the occurrence of asymmetries in foot pronation in young [5] and elderly people [6].

The pelvic motion is dependent on the interaction of the lower limbs [7]. Therefore, it is logical to hypothesize that increased unilateral foot pronation may also influence the biomechanics of the opposite lower limb. Research had demonstrated that during quiet standing, foot pronation increases pelvic ipsilateral drop [8]. If that coupling mechanism remains true for walking, unilateral foot pronation may increase pelvic drop and consequently increases contralateral knee adduction moment [9], which is associated with knee ostearthritis progression [10]. In addition, unilateral foot pronation had been associated to low back pain [6], which reinforces the need to understand the biomechanical effects of unilateral foot pronation.

In order to investigate the effects of foot pronation during walking, different strategies have been implemented on shoes [11], foot orthoses [12] and sandals [13]. Specifically for studies using segmented foot models, the use of sandals seems to be more appropriate, since it was demonstrated that markers placed on shoes overestimate foot segments motion [14]. Regardless of the method chosen, it is usual to make assumptions about the effects of increased foot pronation based on a small set of biomechanical variables, such as the ipsilateral knee adduction moment [15]. However, considering that the influence of increased unilateral foot pronation on pelvic kinematics may also affect the biomechanics of the contralateral lower limb [16], more information about the effects of increased unilateral foot pronation on the mechanics of the lower limbs is necessary.

Therefore, the purpose of this study was to investigate the effects of increased unilateral foot pronation on the biomechanics of the lower limbs during the stance phase of walking. We hypothesized that increased foot pronation will increase ipsilateral lower limb internal rotation angles and ipsilateral pelvic drop and reduce internal rotation moments of the ipsilateral knee and hip. In addition, hip and knee adduction moments of the contralateral lower limb were expected to increase during early stance.

Section snippets

Participants

Sample size was determined as the number of participants necessary to reach a statistical power of 80%, with a significance level of 0.05, considering an expected moderate effect size (d = 0.6) [17]. Twenty-two healthy subjects (10 females, 12 males) with an average age, mass and height of 25 years (SD 4.5), 71.7 kg (SD 11.3) and 175 cm (SD 8), respectively, participated in the study. The inclusion criterion was no history of surgery or injuries to the lower limbs or to the lumbar-pelvic complex in

Gait speed and forefoot eversion

The control, ipsilateral side inclined and contralateral side inclined conditions showed an average gait speed of 1.44 m/s (SD 0.15), 1.45 m/s (SD 0.16) and 1.45 m/s (SD 0.16), respectively, and these differences were not statistically significant (p = 0.69). Wearing the wedged sandal increased forefoot eversion by 5.27° (SD 0.42) throughout stance phase (p < 0.001) when compared to the flat sandal.

Gait variables

The results of ANOVA demonstrated 11 PCs that were significantly different between the three conditions:

Discussion

This study demonstrated that unilateral increased foot pronation affects the biomechanics of the lower limbs during walking. The increased shank and femur internal rotation angles and decreased knee and hip internal rotation moments caused by the wedged sandal supports the existence of the coupling mechanism between rearfoot eversion and lower limb internal rotation [4], [13]. In addition, the increased pelvic ipsilateral drop supports the hypothesis that increased foot pronation dynamically

Conflicts of interest

We wish to confirm that there are no known conflicts of interest associated with this publication and there has been no significant financial support for this work that could have influenced its outcome.

Acknowledgements

The authors are thankful to the Brazilian Government Funding Agencies CAPES and FAPEMIG, grant number PPM00454-13, for financial support. The authors are also thankful to Amy Morton for her contribution during data collection.

References (35)

  • A.G. Schache et al.

    Differences in lower limb transverse plane joint moments during gait when expressed in two alternative reference frames

    J Biomech

    (2007)
  • R.S. Hinman et al.

    Lateral wedge insoles for medial knee osteoarthritis: effects on lower limb frontal plane biomechanics

    Clin Biomech (Bristol, Avon)

    (2012)
  • B. Gurney

    Leg length discrepancy

    Gait Posture

    (2002)
  • Y.C. Lin et al.

    Quantitative evaluation of the major determinants of human gait

    J Biomech

    (2014)
  • K.R. Snyder et al.

    Resistance training is accompanied by increases in hip strength and changes in lower extremity biomechanics during running

    Clin Biomech

    (2009)
  • K.G. Gross et al.

    Varus foot alignment and hip conditions in older adults

    Arthritis Rheum

    (2007)
  • T.R. Souza et al.

    Late rearfoot eversion and lower-limb internal rotation caused by changes in the interaction between forefoot and support surface

    J Am Podiatr Med Assoc

    (2009)
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