Effects of intermittent claudication due to arterial disease on pain-free gait

Abstract

IntroductionStudies of intermittent claudication gait report inconsistent outcomes. Changes in gait are often attributed to degradation of calf muscles, but causation has not been proven through real-time electromyographic data. Neither have effects of walking speed been fully considered. This study aimed to investigate the effect of intermittent claudication on kinematics, kinetics and muscle activity during pain-free gait. Methods18 able bodied individuals and 18 with intermittent claudication walked at their preferred speed while lower limb kinematic, kinetic and electromyography data were collected. FindingsPeople with intermittent claudication walk slower and with reduced step length. Internal ankle plantarflexion moment (P = 0.004, effect size = 0.96) and ankle power generation (P < 0.001, effect size = 1.36) in late stance were significantly reduced for individuals with intermittent claudication. Significant moment and power reductions at the knee and power reduction at hip occurred in early stance, with similar reductions in early and late stance for ground reaction forces. Peak electromyography of soleus activity was significantly reduced in late stance (P = 0.01, effect size = 1.1, n = 13). Effects were independent of walking speed. InterpretationReductions in ankle plantarflexion moments and power generation were consistent with reduced soleus electromyography activity and reduced peak vertical ground reaction forces during late stance. These effects are not due to a reduced walking speed. Changes in knee and hip function are also unrelated to walking speed. These outcomes provide a platform for the design and evaluation of interventions that seek to restore normal walking and improve pain-free walking distances for people with intermittent claudication.