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Lacourpaille L.,University of Nantes | Nordez A.,University of Nantes | Doguet V.,University of Nantes | Hug F.,University of Nantes | Guilhem G.,French National Institute of Sport
Muscle and Nerve | Year: 2016

Introduction: In this study we aimed to quantify the effect of exercise-induced muscle damage on both the electrochemical and mechanical components of electromechanical delay using very-high-frame-rate ultrasound. Methods: Fifteen participants underwent electrically evoked contractions of the medial gastrocnemius muscle with an ultrasound transducer on the muscle belly and on the myotendinous junction, before, 1 hour, and 48 hours after eccentric exercise of the plantar flexor muscles. Results: Maximal isometric plantar flexor torque was significantly lower at 1 hour (-41.1±14.9%; P=0.0001) and 48 hours (-11.9±14.9%; P=0.038) post-exercise compared with pre-exercise. However, the delay between electrical stimulation and the onset of muscle activation, the delay between electrical stimulation and myotendinous junction motion, and the electromechanical delay were not altered significantly by eccentric exercise (P=0.063). Conclusions: These findings suggest that moderate muscle damage does not affect the time for the electrochemical or mechanical components of electromechanical delay. © 2016 Wiley Periodicals, Inc. Source

Doron J.,French National Institute of Sport | Martinent G.,University Claude Bernard Lyon 1
Journal of Sports Sciences | Year: 2016

This study examined the trajectories and within-person synergies of psychological processes during the final stages of matches. A process-oriented approach was used with nine women elite fencers during an international competition. Multiple assessments of perceived control, threat and challenge appraisals, problem- and emotion-focused coping, positive and negative affects were completed after each touches using video recall method. Multilevel growth curve analyses (MGCAs) indicated that winning and losing matches were each characterised by distinct psychological processes. Specifically, perceived control, challenge appraisal, problem- and emotion-focused coping, and positive affects increased linearly and threat appraisal decreased linearly for wining matches, whereas negative affects increased linearly for losing matches. Regarding the within-person synergies of psychological processes, MGCAs indicated that (1) perceived control and challenge appraisal were significantly associated with problem- and emotion-focused coping for losing matches, the strength of these associations remaining consistent across touches; (2) problem-focused coping was significantly associated with negative affects whereas emotion-focused coping was significantly associated with positive affects for winning matches, the strength of these associations remaining consistent across touches; and (3) problem- and emotion-focused coping were significantly associated with negative affects for losing matches, the linear trajectory of negative affects accelerating at times when athletes had higher levels of emotion-focused coping. Overall, this study provided insights into transactional processes during competition. © 2015 Taylor & Francis. Source

Marquet L.-A.,University of Nice Sophia Antipolis | Hausswirth C.,French National Institute of Sport | Hays A.,CREPS Sud Est | Vettoretti F.,CREPS Sud Est | Brisswalter J.,University of Nice Sophia Antipolis
International Journal of Sports Physiology and Performance | Year: 2015

Purpose: To assess the impact of between-training-sessions recovery strategies (passive [PAS], active [ACT], cold-water immersion [CWI], and ingestion of a recovery drink [NUTR]) on maximal cycling performance, perceptions of delayed-onset muscle soreness (DOMS), and fatigue in world-class BMX riders. Methods: Eleven elite BMX athletes, members of the French national team (top country in the 2011 international ranking, 4 medals at the 2012 World Championships, top European country), participated in the study, which involved standardized training periods. Athletes performed 3 maximal-sprint power tests: the first day of the week before the training session and before and after training on the third day of the week (D3). The recovery strategy was randomly assigned to each participant on day 2 immediately after the last training period of the day. Perceptions of DOMS and general fatigue were recorded on D3. Results: After training on D3, the decrease in maximal-sprint power (Pmax) was significantly greater for PAS than with CWI (P = .02) and NUTR (P = .018). Similar results were found with ACT (vs CWI P = .044, and vs NUTR P = .042). Self-reported DOMS and fatigue were significantly greater after PAS than after other strategies. Conclusions: For elite BMX riders, between training days, nutritional and/or CWI recovery strategies appear to be best for reducing muscle fatigue and increasing the capacity to withstand the training schedule. © 2015 Human Kinetics, Inc. Source

Louis J.,French National Institute of Sport | Schaal K.,French National Institute of Sport | Schaal K.,University of California at Davis | Bieuzen F.,French National Institute of Sport | And 5 more authors.
PLoS ONE | Year: 2015

Recent research on whole-body cryotherapy has hypothesized a major responsibility of head cooling in the physiological changes classically reported after a cryostimulation session. The aim of this experiment was to verify this hypothesis by studying the influence of exposing the head to cold during whole-body cryostimulation sessions, on the thermal response and the autonomic nervous system (ANS). Over five consecutive days, two groups of 10 participants performed one whole-body cryostimulation session daily, in one of two different systems; one exposing the whole-body to cold (whole-body cryostimulation, WBC), and the other exposing the whole-body except the head (partial-body cryostimulation, PBC).10 participants constituted a control group (CON) not receiving any cryostimulation. In order to isolate the head-cooling effect on recorded variables, it was ensured that the WBC and PBC systems induced the same decrease in skin temperature for all body regions (mean decrease over the 5 exposures: -8.6°C±1.3°C and -8.3±0.7°C for WBC and PBC, respectively), which persisted up to 20-min after the sessions (P20). The WBC sessions caused an almost certain decrease in tympanic temperature from Pre to P20 (-0.28 ±0.11°C), while it only decreased at P20 (-0.14±0.05°C) after PBC sessions. Heart rate almost certainly decreased after PBC (-8.6%) and WBC (-12.3%) sessions. Resting vagal-related heart rate variability indices (the root-mean square difference of successive normal RR intervals, RMSSD, and high frequency band, HF) were very likely to almost certainly increased after PBC (RMSSD:+49.1%, HF: +123.3%) and WBC (RMSSD: +38.8%, HF: +70.3%). Plasma norepinephrine concentration was likely increased in similar proportions after PBC and WBC, but only after the first session. Both cryostimulation techniques stimulated the ANS with a predominance of parasympathetic tone activation from the first to the fifth session and in slightly greater proportion with WBC than PBC. The main result of this study indicates that the head exposure to cold during whole-body cryostimulation may not be the main factor responsible for the effects of cryostimulation on the ANS. © 2015 Louis et al. Source

Schaal K.,French National Institute of Sport | Schaal K.,University of California at Davis | Le Meur Y.,French National Institute of Sport | Louis J.,French National Institute of Sport | And 4 more authors.
Medicine and Science in Sports and Exercise | Year: 2015

Introduction Elite athletes frequently undergo periods of intensified training (IT) within their normal training program. These periods can lead athletes into functional overreaching, characterized by high perceived fatigue, impaired sleep, and performance. Because whole-body cryostimulation (WBC) has been proven to be an effective recovery method in the short term (<76 h), we investigated whether daily WBC sessions during IT could prevent exercise and sleep-related signs of overreaching. Methods After a normal training week (BASE), 10 elite synchronized swimmers performed two 2-wk IT periods in a randomized crossover fashion using WBC daily (ITWBC) or not (ITCON), separated by 9 d of light training. Swim time trials (400 m) were performed at BASE and after each IT to quantify blood lactate ([La-]B), HR (HR400), salivary alpha amylase ([α-amylase]s400), and cortisol ([cortisol]s400) responses. Swimmers wore a wrist actigraph nightly to monitor sleep patterns. Results Swim speed (400 m), [La-]B400, and [α-amylase]s400 decreased from BASE to ITCON, although no significant changes were found after ITWBC. Decreased swim speed was correlated to decreased HR400 and [cortisol]s400. During ITCON, significant decreases in actual sleep duration (-21 ± 7 min) and sleep efficiency (-1.9% ± 0.8%) were observed, with increased sleep latency (+11 ± 5 min) and fatigue compared with BASE, although these variables did not change during ITWBC. Using a qualitative statistical analysis, we observed that daily WBC use resulted in a 98%, 59%, 66%, and 78% chance of preserving these respective variables compared with ITCON. Conclusion WBC use during IT helped mitigate the signs of functional overreaching observed during ITCON, such as reduced sleep quantity, increased fatigue, and impaired exercise capacity. These results support the daily use of WBC by athletes seeking to avoid functional overreaching during key periods of competition preparation. © 2014 by the American College of Sports Medicine. Source

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