The maximal walking distance (MWD) performed on treadmill (TT) remains the gold standard in estimating the walking capacity of patients suffering from peripheral arterial disease (PAD) with intermittent claudication, although treadmills are not accessible to most physicians. We hypothesized that global positioning system (GPS) recordings could monitor community-based outdoor walking and provide valid information on walking capacity in PAD patients.

The study has two main objectives, conducted together. Each objective include several phases.

Objective 1: technical validation of GPS measurements in healthy subjects.

phase 1: technical validation of a GPS device to study outdoor walking (completed).

phase 2: comparison and use of various GPS devices (intra- and inter-GPS variability) in the study outdoor walking (on-going).

phase 3: study of several factors that could influence accuracy of GPS measurements as walking speed, environment, sampling frequency and others technical features as the WAAS/EGNOS function (on-going).

Objective 2: Application in PAD patients to study walking capacity under free-living conditions

phase 1: comparison of GPS measurements (maximal walking distance) with the gold standard treadmill measurement of maximal walking distance (completed).

phase 2: analysis of the variability of the walking capacity under free-living conditions from GPS measurements (completed).

phase 3: study of reliability and sensibility (effect of treatment) of GPS measurements (on-going).

phase 4: study of the relationship between laboratory measurements of walking capacity and GPS-derived parameters.

Inclusion Criteria:

• Ankle to Brachial Index (ABI) < 0.95 for PAD patients
• Age > 18 years old
• Able to walk on treadmill

Exclusion Criteria:

• limb pain of potential non-vascular origin
• myocardial infraction in the last six months
• uncontrolled angina pectoris