Intralimb coordination variability in peripheral arterial disease

Background Increased variability has been traditionally associated with decreased movement performance due to disease and aging. However, recent research indicates that variability may be of functional importance in motor control. Thus the purpose of this study was to determine whether individuals with peripheral arterial disease and suffering from intermittent claudication have reduced intralimb joint coordination variability compared to individuals without peripheral arterial disease. A further aim was to examine the efficacy of various techniques used to describe intralimb joint coordination variability. Methods Participants with peripheral arterial disease and suffering from intermittent claudication (n = 28) were selected based on an appropriate history of peripheral arterial disease and intermittent claudication, ankle brachial pressure index <0.9 in at least 1 leg and a positive Edinburgh claudication questionnaire response. A further group of participants (n = 25) free of peripheral arterial disease (ankle brachial pressure index >0.9) and who were non-regular exercisers were recruited from the community to act as age and mass matched controls. All participants underwent 2D angular kinematics analysis during normal walking. Intralimb coordination variability was measured using parameterization, vector coding and normalized root mean square techniques applied to relative motion plots of various joint couplings. Differences between groups were examined by one-way ANOVA. Findings Participants with peripheral arterial disease and suffering from intermittent claudication displayed significantly greater intralimb joint coordination variability than age and mass matched controls participants for all joint couplings using all intralimb joint coordination variability techniques. Interpretation These findings suggest that higher levels of intralimb joint coordination variability of the lower limbs in participants with peripheral arterial disease and suffering from intermittent claudication may be an adaptation of the motor control system to deal with perturbations associated with the gradual onset of claudication pain.