The Inter- and Intra-Unit Variability of a Low-Cost GPS Data Logger/Receiver to Study Human Outdoor Walking in View of Health and Clinical Studies

PURPOSE: The present study evaluates the intra- and inter-unit variability of the GlobalSat(R) DG100 GPS data logger/receiver (DG100) when estimating outdoor walking distances and speeds. METHODS: Two experiments were performed using healthy subjects walking on a 400 m outdoor synthetic track. The two experiments consisted of two different outdoor prescribed walking protocols with distances ranging from 50 to 400 m. Experiment 1 examined the intra-unit variability of the DG100 (test-retest reproducibility) when estimating walking distances. Experiment 2 examined the inter-unit variability of four DG100 devices (unit to unit variability) when estimating walking distances and speeds. RESULTS: The coefficient of variation [95% confidence interval], for the reliability of estimating walking distances, was 2.8 [2.5-3.2] %. The inter-unit variability among the four DG100 units tested ranged from 2.8 [2.5-3.2] % to 3.9 [3.5-4.4] % when estimating distances and from 2.7 [2.4-3.0] % to 3.8 [3.4-4.2] % when estimating speeds. CONCLUSION: The present study indicates that the DG100, an economical and convenient GPS data logger/receiver, can be reliably used to study human outdoor walking activities in unobstructed conditions. This device let facilitate the use of GPS in studies of health and disease

Using Global Positioning System to Assess Walking Capacity

International audienc

Estimating Outdoor Walking Energy Expenditure in Non-Steady-State Conditions

International audienc

Utilisation du GPS en vue d’applications médicales : données disponibles

Introduction : L’objectif de cette note brève est de présenter les données disponibles concernant l’utilisation du géo-positionnement satellitaire (GPS) dans un contexte médical. Synthèse des faits : La technique GPS a déjà été utilisée dans trois types de maladies chroniques : la sclérose en plaques, l’artériopathie oblitérante des membres inférieurs et la lombalgie chronique. Ces études montrent l’intérêt de la mesure GPS dans l’évaluation de la capacité de marche des patients. Conclusion : Des études supplémentaires de validation méthodologique et surtout d’application doivent être menées. Des aspects méthodologiques liés à la mesure GPS et des perspectives d’applications sont ici discutés

Applicabilité du GPS dans l’évaluation des limitations à la marche des claudications artérielles

International audienc

Applicability of global positioning system for the assessment of walking ability in patients with arterial claudication

International audienceOBJECTIVE: This study determined for the first time the clinical applicability of a global positioning system (GPS)-monitored community-based walking ability assessment in a large cohort of patients with peripheral artery disease (PAD). METHODS: A multicenter study was conducted among PAD patients who complained of intermittent claudication. Patients equipped with a GPS device performed a community-based outdoor walk. We determined the number of technically satisfactory GPS recordings (attempt No. 1). Patients with unsatisfactory GPS recordings were asked to perform a second attempt (attempt No. 2). From the satisfactory recordings obtained after attempts No. 1 and No. 2, we analyzed several GPS parameters to provide clinical information on the patients' walking ability. Results are reported as median (interquartile range). RESULTS: A total of 218 patients performed an outdoor walk. GPS recordings were technically satisfactory in 185 patients (85%) and in 203 (93%) after attempts No. 1 and No. 2, respectively. The highest measured distance between two stops during community walking was 678 m (IQR, 381-1333 m), whereas self-reported maximal walking distance was 250 m (IQR, 150-400 m; P \textless .001). Walking speed was 3.6 km/h (IQR, 3.1-3.9 km/h), with few variations during the walk. Among the patients who had to stop during the walk, the stop durations were \textless10 minutes in all but one individual. CONCLUSIONS: GPS is applicable for the nonsupervised multicenter recording of walking ability in the community. In the future, it may facilitate objective community-based assessment of walking ability, allow for the adequate monitoring of home-based walking programs, and for the study of new dimensions of walking in PAD patients with intermittent claudication

Caractéristiques physiologiques et anthropométriques des kayakistes de course en ligne de haut niveau de performance

Différences énergétiques entre spécialistes de deux distances olympiques, le 500 m et le 1000 m, à partir de tests de laboratoire sur ergomètre de kayak (VO2 max, PMA, seuil anaérobie), de tests de la puissance musculaire, et par l'analyse des temps de course enregistrés lors de compétitions officielles

The accuracy of a simple, low-cost GPS data logger/receiver to study outdoor human walking in view of health and clinical studies.

Accurate and objective measurements of physical activity and lower-extremity function are important in health and disease monitoring, particularly given the current epidemic of chronic diseases and their related functional impairment.The aim of the present study was to determine the accuracy of a handy (lightweight, small, only one stop/start button) and low-cost (∼$75 with its external antenna) Global Positioning System (GPS) data logger/receiver (the DG100) as a tool to study outdoor human walking in perspective of health and clinical research studies. Methods. Healthy subjects performed two experiments that consisted of different prescribed outdoor walking protocols. Experiment 1. We studied the accuracy of the DG100 for detecting bouts of walking and resting. Experiment 2. We studied the accuracy of the DG100 for estimating distances and speeds of walking.Experiment 1. The performance in the detection of bouts, expressed as the percentage of walking and resting bouts that were correctly detected, was 92.4% [95% Confidence Interval: 90.6-94.3]. Experiment 2. The coefficients of variation [95% Confidence Interval] for the accuracy of estimating the distances and speeds of walking were low: 3.1% [2.9-3.3] and 2.8% [2.6-3.1], respectively.The DG100 produces acceptable accuracy both in detecting bouts of walking and resting and in estimating distances and speeds of walking during the detected walking bouts. However, before we can confirm that the DG100 can be used to study walking with respect to health and clinical studies, the inter- and intra-DG100 variability should be studied.ClinicalTrials.gov NCT00485147