Institute of Physical Education and Sports science IFEPSA

Les Ponts-de-Cé, France

Institute of Physical Education and Sports science IFEPSA

Les Ponts-de-Cé, France
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De Mullenheim P.-Y.,University of Rennes 2 – Upper Brittany | Chaudru S.,University of Rennes 1 | Gernigon M.,University of Angers | Mahe G.,University of Rennes 1 | And 6 more authors.
Physiological Measurement | Year: 2016

The aim of this study was to assess, for the first time, the accuracy of a low-cost global positioning system (GPS) receiver for estimating grade during outdoor walking. Thirty subjects completed outdoor walks (2.0, 3.5 and 5.0 km • h-1) in three randomized conditions: 1/level walking on a 0.0% grade; 2/graded (uphill and downhill) walking on a 3.4% grade; and 3/on a 10.4% grade. Subjects were equipped with a GPS receiver (DG100, GlobalSat Technology Corp., Taiwan; ∼US$75). The GPS receiver was set to record at 1 Hz and its antenna was placed on the right shoulder. Grade was calculated from GPS speed and altitude data (grade = altitude variation/travelled distance × 100). Two methods were used for the grade calculation: one using uncorrected altitude data given by the GPS receiver and another one using corrected altitude data obtained using map projection software (CartoExploreur, version 3.11.0, build 2.6.6.22, Bayo Ltd, Appoigny, France, ∼US$35). Linear regression of GPS-estimated versus actual grade with R 2 coefficients, bias with 95% limits of agreement (95% LoA), and typical error of the estimate with 95% confidence interval (TEE (95% CI)) were computed to assess the accuracy of the GPS receiver. 444 walking periods were performed. Using uncorrected altitude data, we obtained: R 2 = 0.88 (p < 0.001), bias = 0.0 6.6%, TEE between 1.9 (1.7-2.2)% and 4.2 (3.6-4.9)% according to the grade level. Using corrected altitude data, we obtained: R 2 = 0.98 (p < 0.001), bias = 0.2 1.9%, TEE between 0.2 (0.2-0.3)% and 1.0 (0.9-1.2)% according to the grade level. The low-cost GPS receiver used was weakly accurate for estimating grade during outdoor walking when using uncorrected altitude data. However, the accuracy was greatly improved when using corrected altitude data. This study supports the potential interest of using GPS for estimating energy expenditure during outdoor walking. © 2016 Institute of Physics and Engineering in Medicine.


Noury-Desvaux B.,Institute of Physical Education and Sports science IFEPSA | Noury-Desvaux B.,University of Angers | Abraham P.,University of Angers | Mahe G.,University of Angers | And 5 more authors.
PLoS ONE | Year: 2011

Introduction: 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. Purpose: 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. Results: 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. Conclusion: 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. Trial Registration: ClinicalTrials.gov NCT00485147. © 2011 Noury-Desvaux et al.


Le Faucheur A.,University of Angers | Le Faucheur A.,Institute of Physical Education and Sports science IFEPSA | Noury-Desvaux B.,Institute of Physical Education and Sports science IFEPSA | Mahe G.,University of Angers | And 8 more authors.
Journal of Vascular Surgery | Year: 2010

Objective: Global positioning system (GPS) recordings can provide valid information on walking capacity in patients with peripheral arterial disease (PAD) and intermittent claudication (IC) during community-based outdoor walking. This study used GPS to determine the variability of the free-living walking distance between two stops (WDBS), induced by lower-limb pain, which may exist within a single stroll in PAD patients with IC and the potential associated parameters obtained from GPS analysis. Methods: This cross-sectional study of 57 PAD patients with IC was conducted in a university hospital. The intervention was a 1-hour free-living walking in a flat public park with GPS recording at 0.5 Hz. GPS-computed parameters for each patient were WDBS, previous stop duration (PSD), cumulated time from the beginning of the stroll, and average walking speed for each walking bout. The coefficient of variation of each parameter was calculated for patients with the number of walking bouts (NWB) ≥5 during their stroll. A multivariate analysis was performed to correlate WDBS with the other parameters. Results: Mean (SD) maximal individual WDBS was 1905 (1189) vs 550 (621) meters for patients with NWB <5 vs NWB ≥ 5, respectively (P < .001). In the 36 patients with NWB ≥ 5, the coefficient of variation for individual WDBS was 43%. Only PSD and cumulated time were statistically associated with WDBS in 16 and 5 patients, respectively. Conclusions: A wide short-term variability of WDBS exists and likely contributes to the difficulties experienced by patients with IC to estimate their maximal walking distance at leisurely pace. Incomplete recovery from a preceding walk, as estimated through PSD, seems to dominantly account for the WDBS in patients with IC. © 2010 Society for Vascular Surgery.


Abraham P.,University of Angers | Noury-Desvaux B.,University of Angers | Noury-Desvaux B.,Institute of Physical Education and Sports science IFEPSA | Gernigon M.,University of Angers | And 6 more authors.
PLoS ONE | Year: 2012

Purpose: The present study evaluates the intra- and inter-unit variability of the GlobalSat® 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. © 2012 Abraham et al.


Gastinger S.,University of Rennes 2 – Upper Brittany | Gastinger S.,Institute of Physical Education and Sports science IFEPSA | Donnelly A.,University of Limerick | Dumond R.,University of Rennes 2 – Upper Brittany | Prioux J.,University of Rennes 2 – Upper Brittany
Journal of Parenteral and Enteral Nutrition | Year: 2014

Precise measurement of sedentary behavior and physical activity is necessary to characterize the dose-response relationship between these variables and health outcomes. The most frequently used methods employ portable devices to measure mechanical or physiological parameters (eg, pedometers, heart rate monitors, accelerometers). There is considerable variability in the accuracy of total energy expenditure (TEE) estimates from these devices. This review examines the potential of measurement of ventilation (V·E) to provide an estimate of free-living TEE. The existence of a linear relationship between V·E and energy expenditure (EE) was demonstrated in the mid-20th century. However, few studies have investigated this parameter as an estimate of EE due to the cumbersome equipment required to measure V·E. Portable systems that measure V·E without the use of a mouthpiece have existed for about 20 years (respiratory inductive plethysmography). However, these devices are adapted for clinical monitoring and are too cumbersome to be used in conditions of daily life. Technological innovations of recent years (small electromagnetic coils glued on the chest/back) suggest that V·E could be estimated from variations in rib cage and abdominal distances. This method of TEE estimation is based on the development of individual/group calibration curves to predict the relationship between ventilation and oxygen consumption. The new method provides a reasonably accurate estimate of TEE in different free-living conditions such as sitting, standing, and walking. Further work is required to integrate these electromagnetic coils into a jacket or T-shirt to create a wearable device suitable for long-term use in free-living conditions. © 2014 American Society for Parenteral and Enteral Nutrition.


PubMed | Institute of Physical Education and Sports science IFEPSA
Type: Journal Article | Journal: PloS one | Year: 2011

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.

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