Prolonged stance phase during walking in intermittent claudication.

BACKGROUND

Patients with intermittent claudication (IC) tend to walk slower and consume approximately 40% more oxygen during walking compared with healthy individuals. An unfavorable locomotion pattern has been suggested to explain this metabolic inefficiency. However, detailed knowledge of gait parameters in IC is lacking.

METHODS

In a cross-sectional study, the gait pattern of newly diagnosed IC patients was compared with that of healthy controls. Spatiotemporal gait parameters such as step length and duration of stance phase were obtained by a photoelectric technique (OptoGait; Microgate, Bolzano, Italy). This system was previously found to have favorable concurrent validity and test-retest reliability characteristics. Parameters were determined during pain-free and painful treadmill walking at a comfortable self-determined walking pace. Each parameter was averaged on the basis of 80 steps.

RESULTS

A total of 28 patients and 28 controls were examined. IC patients walked 1.2 km/h (-27%) slower than controls (P < .001), coinciding with a significantly shorter step length (-20%) and lower cadence (-11%). IC patients demonstrated a longer stance and double support phase, even before the onset of ischemic pain. Differences were also observed in segments of the stance phase, as a 14% shorter propulsion (P < .001) and 17% longer flat foot phase (P < .001) during painful walking were found. In considering the absolute duration of these stance phase segments, differences were found only for the flat foot time (Δ0.10 second; P < .001).

CONCLUSIONS

Patients with IC demonstrate an altered gait pattern compared with healthy controls. The most prominent differences were a prolonged relative and absolute duration of the flat foot position during the stance phase. This adaptation may be intuitive as an augmented arterial blood flow into skeletal muscles is allowed during a prolonged relaxation phase. Therefore, not only the lack of propulsion but also a gain of relaxation may explain these gait alterations.