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Dupont G.,Lille 2 University of Health and Law | Dupont G.,9 Rue Of Luniversite | Dupont G.,Celtic Laboratory | Nedelec M.,Lille 2 University of Health and Law | And 5 more authors.
American Journal of Sports Medicine | Year: 2010

Background: Recovery duration may be too short during the congested fixtures of professional soccer players with regard to maintaining physical performance and a low injury rate. Purpose: To analyze the effects of 2 matches per week on physical performance and injury rate in male elite soccer players. Study Design: Cohort study; Level of evidence, 3. Methods: Match results, match-related physical performance, and injuries were monitored during 2 seasons (2007-2008 and 2008- 2009) for 32 professional soccer players in a top-level team participating in the UEFA (Union of European Football Associations) Champions League. Total distance, high-intensity distance, sprint distance, and number of sprints were collected for 52 home matches. Injuries and player participation in matches and training were recorded throughout the full season. Results: Physical performance, as characterized by total distance covered, high-intensity distance, sprint distance, and number of sprints, was not significantly affected by the number ofmatches per week (1 versus 2), whereas the injury rate was significantly higher when players played 2 matches per week versus 1 match per week (25.6 versus 4.1 injuries per 1000 hours of exposure; P<.001). Conclusion: The recovery time between 2 matches, 72 to 96 hours, appears sufficient to maintain the level of physical performance tested but is not long enough to maintain a low injury rate. The present data highlight the need for player rotation and for improved recovery strategies to maintain a low injury rate among athletes during periods with congested match fixtures. © 2010 The Author(s).

Coquart J.B.J.,Clinical Research Unit | Coquart J.B.J.,University of Lille Nord de France | Coquart J.B.J.,9 Rue Of Luniversite | Eston R.G.,University of Exeter | And 5 more authors.
European Journal of Applied Physiology | Year: 2010

The purpose of this study was to develop a simple, convenient and indirect method for predicting peak oxygen uptake (VO2peak) from a sub-maximal graded exercise test (GXT), in obese women. Thirty obese women performed GXT to volitional exhaustion. During GXT, oxygen uptake and the power at RPE 15 (PRPE15) were measured, and VO2peak was determined. Following assessment of the relationships between VO2peak and P RPE15, age, height and mass were made available in a stepwise multiple regression analysis with VO2peak as the dependent variable. The equation to predict VO2peak was: VO2peak(1 min -1) =1.355-9.920e-3 × age + 8.497e-3 × PRPE15 (r = 0.83; SEE = 0.156 l min-1). This study suggests that age and PRPE15 elicited during a sub-maximal GXT provides a reasonably accurate prediction of VO2peak in obese women. © 2010 Springer-Verlag.

Borel B.,University of Lille Nord de France | Borel B.,9 Rue Of Luniversite | Leclair E.,University of Lille Nord de France | Leclair E.,9 Rue Of Luniversite | And 6 more authors.
Pediatric Pulmonology | Year: 2011

Background The aim of this study was to evaluate the occurrence and severity of mechanical ventilatory constraints in healthy prepubescent children during continuous and intermittent exercise. Methods Twelve prepubescent children (7-11 years old) performed 7 exercises on a treadmill: one graded test for the determination of maximal aerobic speed (MAS), three continuous exercises (CE) at 60, 70, and 80% of MAS and three intermittent exercises (IE), alternating 15 sec of exercise with 15 sec of passive recovery, at 90, 100, and 110% of MAS. During each CE and IE, tidal flow/volume loops were plotted within a maximal flow/volume loop (MFVL) measured at rest before each exercise. Expiratory flow limitation (expFL expressed in %Vt) was defined as the part of exercise tidal volume (Vt) meeting the boundary of MFVL. Breathing strategy was estimated by measuring inspiratory capacity relative to forced vital capacity and tidal volume relative to inspiratory capacity. Other breathing pattern parameters (ventilation VE, Vt, respiratory frequency f) were continuously recorded during exercise. Results An "intensity" effect was found for V̇E during CE (P < 0.001) but not during IE (P = 0.08). The increase in V̇E was predominantly assumed by an increase in f for both exercise modalities. During each exercise, several children heterogeneously experienced expFL ranging between 10 and 90%Vt. For all exercises, Vt was predominantly regulated by an increase in Vt/IC with no change in IC/FVC from rest to exercise. Finally, no significant "modality" effect was found for mechanical ventilatory constraint parameters (expFL, Vt/IC, and IC/FVC). Discussion We could conclude that neither of the modalities studied induced more mechanical ventilatory constraints than the other, but that exercise intensities specific to each modality might be greater sources of exacerbation for mechanical ventilatory constraints. © 2011 Wiley-Liss, Inc.

Borel B.,University of Lille Nord de France | Borel B.,9 Rue Of Luniversite | Leclair E.,University of Lille Nord de France | Leclair E.,9 Rue Of Luniversite | And 6 more authors.
Pediatric Pulmonology | Year: 2014

Aim: To analyze breathing pattern and mechanical ventilatory constraints during incremental exercise in healthy and cystic fibrosis (CF) children. Methods: Thirteen healthy children and 6 children with cystic fibrosis volunteered to perform an incremental test on a treadmill. Exercise tidal flow/volume loops were plotted every minute within a maximal flow/volume loop (MFVL). Expiratory flow limitation (expFL expressed in %Vt) was evaluated and end-expiratory and end-inspiratory lung volumes (EELV and EILV) were estimated from expiratory reserve volume relative to vital capacity (ERV/FVC) and from inspiratory reserve volume relative to vital capacity (IRV/FVC). Results: During the incremental exercise, expFL was first observed at 40% of maximal aerobic speed in both groups. At maximal exercise, 46% of healthy children and 83% of CF children presented expFL, without significant effect of cystic fibrosis on the severity of expFL. According to the two-way ANOVA results, both groups adopted similar breathing pattern and breathing strategies as no significant effect of CF has been revealed. But, according to one-way ANOVA results, a significant increase of ERV/FVC associated with a significant decrease of IRV/FVC from resting value shave been observed in healthy children at maximal exercise, but not in CF children. Discussion: The hypothesis of this study was based on the assumption that mild cystic fibrosis could induce more frequent and more severe mechanical ventilatory constraints due to pulmonary impairment and breathing pattern disturbances. But, this study did not succeed to highlight an effect of mild cystic fibrosis on the mechanical ventilatory constraints (expFL and dynamic hyperinflation) that occur during an incremental exercise. This absence of effect could be due to the absence of an impact of the disease on spirometric data, breathing pattern regulation during exercise and breathing strategy. © 2013 Wiley Periodicals, Inc.

Oussaidene K.,University of Lille Nord de France | Oussaidene K.,9 Rue Of Luniversite | Prieur F.,University Paris - Sud | Bougault V.,University of Lille Nord de France | And 6 more authors.
European Journal of Applied Physiology | Year: 2013

This study aimed to investigate the involvement of cerebral oxygenation in limitation of maximal exercise. We hypothesized that O2 supplementation improves physical performance in relation to its effect on cerebral oxygenation during exercise. Eight untrained men (age 27 ± 6 years; VO2max 45 ± 8 ml min-1 kg-1) performed two randomized exhaustive ramp exercises on a cycle ergometer (1 W/3 s) under normoxia and hyperoxia (FIO2 = 0.3). Cerebral (ΔCOx) and muscular (ΔMOx) oxygenation responses to exercise were monitored using near-infrared spectroscopy. Power outputs corresponding to maximal exercise intensity, to threshold of ΔCOx decline (ThCOx) and to the respiratory compensation point (RCP) were determined. Power output W max = 302 ± 20 vs. 319 ± 28 W) and arterial O 2 saturation estimated by pulse oximetry (SpO2 = 95.7 ± 0.9 vs. 97.0 ± 0.5 %) at maximal exercise were increased by hyperoxia (P < 0.05). However, the ΔMOx response during exercise was not significantly modified with hyperoxia. RCP (259 ± 17 vs. 281 ± 25 W) and ThCOx (259 ± 23 vs. 288 ± 30 W) were, however, improved (P < 0.05) with hyperoxia and the ThCOx shift was related to the (Wmax improvement with hyperoxia (r = 0.71, P < 0.05). The relationship between the change in cerebral oxygenation response to exercise and the performance improvement with hyperoxia supports that cerebral oxygenation is limiting the exercise performance in healthy young subjects. © 2013 Springer-Verlag Berlin Heidelberg.

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