The Validity of the Single-Leg Heel Raise Test in People With Multiple Sclerosis: A Cross-Sectional Study

Abstract

Background: The single-leg heel raise test is a common clinical assessment; however, little is known about its validity in people with multiple sclerosis (MS). This study investigated the validity of the single-leg heel raise test in a group of people with MS and a healthy control group (CTL). Materials and Methods: Twenty-one people with MS (49 ± 12 years, Expanded Disability Status Scale 1.5-5.5) and 10 healthy controls (48 ± 12 years) performed the single-leg heel raise test, ankle plantarflexion isometric strength assessment using electromechanical dynamometry, and mobility measures (Timed 25-Foot Walk, 2-Min Walk Test, Functional Stair Test). Results: Convergent validity between the heel raise test and strength was moderate for participants with MS completing <20 heel raises (r = 0.63, p = 0.001) but weak for the entire sample (r = 0.30, p = 0.020). Compared to the average CTL group values, the heel raise test differentiated between groups on the MS groups' weaker (p < 0.001) and stronger (p = 0.003) limbs, while strength only differentiated between groups on the weaker limb (p = 0.010). Considering the weaker and strong limbs from the MS group and the CTL group average values, the mobility measures had moderate-to-strong correlations with the heel raise test on the weaker MS limb + CTL (r = 0.71-0.78) and stronger MS limb + CTL (r = 0.62-0.70), and weak-to-moderate correlations with strength on the weaker MS limb + CTL (r = 0.49-0.58, p = 0.001-0.007). Discussion: In people with MS, the single-leg heel raise test may be clinically useful as it identified impaired muscle performance and differentiated muscle performance from a healthy control group and, together with the control group, correlated with functional mobility.

Keywords: functional mobility; multiple sclerosis; muscle performance; rehabilitation; strength.

Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Copyright © 2021 Mañago, Kline, Harris-Love and Christiansen.

Figures

Figure 1

Relationship of the single-leg heel raise test to plantarflexion isometric strength in (A) the overall sample (n = 62), (B) the MS group only (n = 42), and (C) considering any limb that completed <20 heel raises (n = 24). • = participants with MS; △ = healthy control.

Figure 2

Scatter plots and Pearson values for ankle plantarflexion muscle performance measures to functional mobility. • = participants with MS; □ = healthy control. *Significant based on Bonferroni corrected α = 0.05/12 = 0.004. T25FW, timed 25-foot walk; 2MWT, 2-min walk test; FST, functional stair test.