Evaluating ankle dorsiflexion in people with multiple sclerosis: Weight bearing vs. non-weight bearing methods

Ankle joint contractures are common in Multiple Sclerosis (MS), significantly reducing dorsiflexion range of motion, hindering gait and increasing falls. Accurate, standardised ankle dorsiflexion measures for neurologically impaired populations are lacking. This study compared validity and reliability of the non-torque-controlled Weight-Bearing Lunge Test with the torque-controlled Modified Lidcombe Template in assessing ankle dorsiflexion among people with and without MS.

Sixty participants were included: 20 with MS, 20 healthy matched controls, and 20 young adults. Ankle dorsiflexion was assessed bilaterally in knee-flexed and knee-extended positions using both methods. Concurrent validity was analyzed using correlation coefficients. Discriminative validity was evaluated by comparing dorsiflexion between affected and less-affected sides in the MS group and contralaterally in controls. Intra-rater reliability was assessed with Intraclass Correlation Coefficients from measurements taken seven days apart.

High correlations were found between both tests in knee-flexed positions (r = 0.76) but moderate correlations in knee-extension (r = 0.58). The Weight-Bearing Lunge Test demonstrated greater sensitivity in detecting differences between affected and less-affected sides in MS, particularly in knee-flexion (effect size d = -1.04). However, knee-extension measures were less consistent, proving unsuitable for 20 % of MS participants due to balance limitations. The Modified Lidcombe Template exhibited excellent reliability across all conditions (> 0.90), with higher torques differentiating between affected and less-affected sides in MS.

The Modified Lidcombe Template offers greater consistency and appropriateness for neurological conditions. Measuring resistance to passive movement at higher torques provides a comprehensive understanding of contractures, potentially improving diagnostic accuracy.