Rearfoot-forefoot profile defined by vertical ground reaction forces during gait is altered in patients with unilateral intermittent claudication

Abstract

Intermittent Claudication due to Peripheral Arterial Disease (PAD-IC) induces ischemic pain in exercising muscles, and therefore impaired gait. In a pathological context, the analysis of the Vertical component of Ground Reaction Force (VGRF) is frequently used to describe gait pattern. This paper aims to define gait profiles according to the relative difference between peaks of VGRF; a Rearfoot and a Forefoot profile revealing a more loading or push-off strategy. We evaluated 70 participants (24 with unilateral disease (Unilat-IC), 22 with bilateral disease (Bilat-IC) and 24 Controls) during a walk test on an instrumented treadmill. Results indicate that Unilat-IC patients present a Rearfoot-profile in both legs during the pain-free gait period, likely to stabilize their gait. With the onset and increase of pain, the asymptomatic leg changes for a Forefoot-profile. This asymmetrical pattern suggests that a compensatory mechanism occurred to unload the symptomatic (painful) leg, possibly creating an imbalance. In Bilat-IC and Controls subjects, a Forefoot-profile is found, with a symmetrical pattern. However, there is a trend for lower propulsive capacity in case of Bilat-IC due to ischemic pain, but patients did not have the ability to compensate as in Unilat-IC. Therefore, Bilat-IC should not be considered as a “double” Unilat-IC. This study highlights the existence of gait profiles based on VGRF in PAD-IC patients. These profiles are dependent on the type of disease. Analysis of these gait profiles can 1) provide a simple way to identify gait alterations and 2) participate in improving physical rehabilitation strategies in PAD-IC patients.