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Purpose:This study examined the effects of a five-week intervention combining vigorous interval training (VIT) with diet among twenty-four obese adolescents. Fourteen girls and ten boys (aged 14–15) schooled in a pediatric rehabilitation center participated. Methods:The VIT intensity was targeted and remained above 80% of maximal heart rate (HR) and over six kilocalories per minute. Pre- and postintervention measures were body composition (BMI, weight, body fat percentage), physical self-perceptions (PSP), physical fitness (6-min walking distance and work) and its associated physiological responses (HRpeak and blood lactate concentration). A series of two-way analyses of variance or covariance controlling for weight loss were used to examine the changes. Results:Significant improvements were found in body composition, physical fitness and PSP (endurance, activity level, sport competence, global physical self-concept and appearance). In addition, boys presented higher levels of perceived strength and global physical self-concept than girls. Finally, there was a significant increase in perceived endurance, sport competence, and global physical self-concept in girls only. Conclusion:This five-week VIT program combined with diet represents an effective means for improving body composition, physical fitness, and PSP in obese adolescents, the effects on PSP being larger among girls.

Background Health effects of sedentary behaviors (SB) may vary depending on their characteristics such as type, purpose, duration, and intensity of the behavior. While a growing number of questionnaires assess sedentary behaviors, it is unclear which characteristics of SB are measured. The aim of this review was to examine the content of self-report SB questionnaires. Methods Three databases were searched for sedentary behavior questionnaires published before January 1st, 2016. Based on the inclusion criteria, 82 articles out of 1369 were retrieved for a total of 60 questionnaires. For each questionnaire, the sedentary behavior characteristics identified were reported and analyzed. Results Most of the questionnaires assessed the time (n = 60), posture (n = 54), purpose (n = 46) and the types (n = 45) of SB performed. Fewer questionnaires assessed the environment (n = 20) social context (n = 11), status (n = 2), and associated behaviors (n = 2) related to sedentary behaviors. All the questionnaires except two assessed time spent in SB with 17 assessing frequency and 6 assessing breaks in SB. The most frequent characteristics identified in the questionnaires were the categories of sitting (90%), a day (95%), watching television (65%) and using a computer (55%). Many characteristics of SB were not measured. Conclusions By knowing the breadth of SB included in questionnaires, this review provides support to shape the design of new questionnaires designed to reduce the gaps in measuring sedentary behaviors.

The purpose of this study was to identify the influence of different magnitudes and directions of the vibration platform acceleration on surface electromyography (sEMG) during whole-body vibration (WBV) exercises. Therefore, a WBV platform was used that delivers vertical vibrations by a side-alternating mode, horizontal vibrations by a circular mode, and vibrations in all 3 planes by a dual mode. Surface electromyography signals of selected lower limb muscles were measured in 30 individuals while they performed a static squat on a vibration platform. The WBV trials included 2 side-alternating trials (Side-L: 6 Hz, 2.5 mm; Side-H: 16 Hz, 4 mm), 2 circular trials (Circ-L: 14 Hz, 0.8 mm; Circ-H: 43 Hz, 0.8 mm), and 4 dual-mode trials that were the combinations of the single-mode trials (Side-L/Circ-L, Side-L/Circ-H, Side-H/Circ-L, Side-H/Circ-H). Furthermore, control trials without vibration were assessed, and 3-dimensional platform acceleration was quantified during the vibration. Significant increases in the root mean square of the sEMG (sEMGRMS) compared with the control trial were found in most muscles for Side-L/Circ-H (+17 to +63%, p ≤ 0.05), Side-H/Circ-L (+7 to +227%, p ≤ 0.05), and Side-H/Circ-H (+21 to +207%, p < 0.01) and in the lower leg muscles for Side-H (+35 to +138%, p ≤ 0.05). Furthermore, only the vertical platform acceleration showed a linear relationship (r = 0.970, p < 0.001) with the averaged sEMGRMS of the lower limb muscles. Significant increases in sEMGRMS were found with a vertical acceleration threshold of 18 m·s(-2) and higher. The present results emphasize that WBV exercises should be performed on a platform that induces vertical accelerations of 18 m·s(-2) and higher.

International audience; The purpose of this study was to compare lower limb muscle activity between physically active and inactive individuals during whole-body vibration exercises. Additionally, transmissibility of the vertical acceleration to the head was quantified. 30 active and 28 inactive participants volunteered to stand in a relaxed (20°) and a squat (60°) position on a side-alternating WBV platform that induced vibrations at 16 Hz and 4 mm amplitude. Surface electromyography (sEMG) was measured in selected lower limb muscles and was normalized to the corresponding sEMG recorded during a maximal voluntary contraction. The vertical acceleration on the head was evaluated and divided by the vertical platform acceleration to obtain transmissibility values. Control trials without vibration were also assessed. The outcomes of this study showed that (1) WBV significantly increased muscle activity in the active (absolute increase: +7%, P 0.05). However, (3), transmissibility to the head was greater in the active (0.080) than the inactive participants (0.065, P

PURPOSE This study aimed to investigate the effect of different magnitudes of deception on performance and exercise-induced fatigue during cycling time trial. METHODS After three familiarization visits, three women and eight men performed three 5-km cycling time trials while following a simulated dynamic avatar reproducing either 100% (5K100%), 102% (5K102%), or 105% (5K105%) of the subject's previous fastest trial. Quadriceps muscle activation was quantified with surface electromyography. Fatigue was quantified by preexercise to postexercise (10 s through 15 min recovery) changes in quadriceps maximal voluntary contraction (MVC) force, potentiated twitch force evoked by electrical femoral nerve stimulation (QTSingle) and voluntary activation (VA, twitch interpolation technique). RESULTS Greater quadriceps muscle activation in 5K102% versus 5K100% (12% ± 11%) was found in parallel with a 5% ± 2% and 2% ± 1% improvement in power output and completion time, respectively (P < 0.01). Exercise-induced reduction in MVC force and VA were 14% ± 19% and 28% ± 31% greater at exercise termination (at 10 s), whereas QTSingle recovery (from 10 s to 15 min) was 5% ± 5% less in 5K102% versus 5K100% (P < 0.01). No difference in performance or fatigue indices measured at exercise termination was found between 5K100% and 5K105%. CONCLUSIONS Muscle activation and performance improvements during a deceptive cycling time trial were achieved only with a 2% magnitude of deception and were associated with a further impairment in MVC force, QTSingle recovery and VA compared to control. Performance improvement during cycling time trial with augmented deceptive feedback therefore resulted in exacerbated exercise-induced peripheral and central fatigue.

International audience; This study aims to examine the repeated effects of three sessions of vigorous interval training (VIT) in basketball, running-biking, and boxing on the physical self-perceptions (PSP) of obese adolescents participating in a dietary program. A sample of 24 obese adolescents performed the consecutive VIT sessions every week for 5 weeks. PSP were measured immediately after each training session. Analyses of covariance were used to examine changes in PSP. The results showed rapid and constant increases in PSP with significant differences according to sex, time, type of VIT, and an interaction of sex by time by type of VIT, mainly for basketball.

International audience; The acute-exercise effects upon cognitive functions are varied and dependent upon exercise duration and intensity, and the type of cognitive tasks assessed. The hypofrontality hypothesis assumes that prolonged exercise, at physiologically challenging intensities, is detrimental to executive functions due to cerebral perturbations (indicated by reduced prefrontal activity). The present study aimed to test this hypothesis by measuring oxygenation in prefrontal and motor regions using near-infrared spectroscopy during two executive tasks (flanker task and 2-back task) performed while cycling for 60 min at a very low intensity and an intensity above the ventilatory threshold. Findings revealed that, compared to very low intensity, physiologically challenging exercise (i) shortened reaction time in the flanker task, (ii) impaired performance in the 2-back task, and (iii) initially increased oxygenation in prefrontal, but not motor regions, which then became stable in both regions over time. Therefore, during prolonged exercise, not only is the intensity of exercise assessed important, but also the nature of the cognitive processes involved in the task. In contrast to the hypofrontality hypothesis, no inverse pattern of oxygenation between prefrontal and motor regions was observed, and prefrontal oxygenation was maintained over time. The present results go against the hypofrontality hypothesis. (C) 2017 Elsevier Inc. All rights reserved.

Purpose:To investigate the effect of different limb blood-flow levels on cycling-performance recovery, blood lactate concentration, and heart rate.Methods:Thirty-three high-intensity intermittent-trained athletes completed two 30-s Wingate anaerobic test sessions, 3 × 30-s (WAnT 1–3) and 1 × 30-s (WAnT 4), on a cycling ergometer. WAnT 1–3 and WAnT 4 were separated by a randomly assigned 24-min recovery intervention selected from among blood-flow restriction, passive rest, placebo stimulation, or neuromuscular electrical-stimulation-induced blood flow. Calf arterial inflow was measured by venous occlusion plethysmography at regular intervals throughout the recovery period. Performance was measured in terms of peak and mean power output during WAnT 1 and WAnT 4.Results:After the recovery interventions, a large (r = .68 [90% CL .42; .83]) and very large (r = .72 (90% CL .49; .86]) positive correlation were observed between the change in calf arterial inflow and the change in mean and peak power output, respectively. Calf arterial inflow was significantly higher during the neuromuscular-electrical-stimulation recovery intervention than with the blood-flow-restriction, passive-rest, and placebo-stimulation interventions (P < .001). This corresponds to the only intervention that allowed performance recovery (P > .05). No recovery effect was linked to heart rate or blood lactate concentration levels.Conclusions:For the first time, these data support the existence of a positive correlation between an increase in blood flow and performance recovery between bouts of high-intensity exercise. As a practical consideration, this effect can be obtained by using neuromuscular electrical stimulation-induced blood flow since this passive, simple strategy could be easily applied during short-term recovery.

International audience; The influence of vitamin and mineral complex supplementation on muscular activity and cycling efficiency was examined in elderly endurance-trained master athletes during a heavy cycling trial. Master athletes were randomly assigned in a double-blind process to 1 of 2 treatment groups: antioxidant supplementation (n = 8: As group) or placebo (n = 8: Pl group) for 21 days. After that time, each subject had to perform a 10-min session of cycling on a cycloergometer at a heavy constant intensity. Twenty-four to 48 h after this session, subjects performed an isometric maximal voluntary contraction before and immediately after a fatiguing strength training (leg press exercise) and the same 10-min cycling test after fatigue. Isometric maximal voluntary force (MVF) of knee extensors was assessed before and after fatigue. Electromyographic (EMG) activity of the vastus medialis, the vastus lateralis (VL), and the biceps femoris was recorded with surface EMG. The knee-extensors MVF after the fatiguing exercise was reduced in similar proportions for both groups (As, –10.9%; Pl, –11.3%, p < 0.05). This MVF loss was associated with a significant reduction in EMG frequency parameters for both groups, with a lower decrease for the As group. Muscular activity and cycling efficiency during the cycling bouts were affected by the treatment. Cycling efficiency decreased significantly and the oxygen uptake slow component was higher after the fatiguing exercise for both groups. Furthermore, a decrease in cycling efficiency was associated with an increase in VL activity. However, these changes were significantly lower for the As group. The results of the present study indicate an overall positive effect of vitamin and mineral complex supplementation on cycling efficiency after fatigue, in the endurance-trained elderly.; L'objet de cette étude était d'analyser l'influence d'une supplémentation en vitamines et minéraux sur la performance musculaire et le rendement au cours d'un exercice de cyclisme intense. Deux groupes de 8 personnes âgées régulièrement entrainées en endurance, ont été constitués selon une procédure en double aveugle avec l'apport soit d'un complexe d'antioxydants (n = 8 : groupe As), soit d'un placebo (n = 8 : groupe Pl) pendant 21 jours. Après 21 jours de supplémentation chaque sujet devait effectuer une session de cyclisme de 10 min à une intensité intense. 24 à 48 h après cette session les sujets réalisait un test d'évaluation de la force maximale volontaire (FMV) avant et après une séance d'entrainement en résistance et le même exercice de cyclisme après fatigue. La force maximale isométrique volontaire (FMV) des extenseurs du genou était testée avant et après fatigue. L'activité électromyographique (EMG) du vastus medialis (VM), vastus lateralis (VL) et biceps femoris (BF) était enregistrée à partir d'électrodes de surface. La FMV des muscles extenseurs du genou était réduite après l'exercice fatigant, dans des proportions similaires pour les 2 groupes (As, –10,9%; Pl, –11,3%, p < 0,05). Cette baisse de la FMV était accompagnée d'une réduction des paramètres EMG fréquentiels, pour les 2 groupes, avec toutefois une moindre diminution pour le groupe As. La tolérance à l'exercice en cyclisme était modifiée entre les 2 sessions. Le rendement en cyclisme était réduit et la composante lente de consommation d'oxygène était augmentée pour les 2 groupes après l'exercice fatigant. Cette altération du rendement en cyclisme était accompagnée d'une augmentation de l'activité musculaire du VL. Néanmoins ces changements étaient significativement moindres pour le groupe As. Les résultats de cette étude suggèrent un effet bénéfique d'une supplémentation en vitamines et minéraux sur le rendement en cyclisme après fatigue, chez des personnes âgées entraînées en endurance. Mots-clés : vieillissement, électromyographie, rendement en cyclisme, force maximale volontaire, athlète master.

Epub 2015 Jul 17; Overground sprint studies have shown the importance of net horizontal ground reaction force impulse (IMPH) for acceleration performance, but only investigated one or two steps over the acceleration phase, and not in elite sprinters. The main aim of this study was to distinguish between propulsive (IMPH+) and braking (IMPH−) components of the IMPH and seek whether, for an expected higher IMPH, faster elite sprinters produce greater IMPH+, smaller IMPH−, or both.Nine high-level sprinters (100-m best times range: 9.95–10.60 s) performed 7 sprints (2×10 m, 2×15 m, 20 m, 30 m and 40 m) during which ground reaction force was measured by a 6.60 m force platform system. By placing the starting-blocks further from the force plates at each trial, and pooling the data, we could assess the mechanics of an entire “virtual” 40-m acceleration.IMPH and IMPH+ were significantly correlated with 40-m mean speed (r=0.868 and 0.802, respectively; P

International audience; Background/Study Context: Based on the stereotype content model and the behaviors from intergroup affect and stereotypes map (Cuddy et al., 2008; Advances in experimental social psychology [Vol. 40, pp. 61–149], New York: Academic Press), we examined whether being physically active may challenge the traditional stereotypes related to older adults.Methods: We compared how 94 participants (Mage = 24.48 years, SD = 7.15 years) judged one of three target groups (older adults in general, physically active older adults, and socially active older adults), with regard to perceived status and competition, warmth and competence judgments, emotional and behavioral reactions.Results: Results showed that being physically active was associated with higher status and competence. Physically active older adults were specifically viewed as an admired group eliciting both active (helping) and passive facilitation (associating) tendencies.Conclusion: Beyond the well-known health perspective related to the regular participation of older adults in physical activity, the present results open a social optimistic perspective, in which being physically active seems a promising way to challenge the widespread and resistant stereotype content of older people commonly perpetuated.

International audience; This study aimed at investigating concurrent changes in cognitive control and cerebral oxygenation (Cox) during steady intense exercise to volitional exhaustion. Fifteen participants were monitored using prefrontal near-infrared spectroscopy and electromyography of the thumb muscles during the completion of an Eriksen flanker task completed either at rest (control condition) or while cycling at a strenuous intensity until exhaustion (exercise condition). Two time windows were matched between the conditions to distinguish a potential exercise-induced evolutive cognitive effect: an initial period and a terminal period. In the initial period, Cox remained unaltered and, contrary to theoretical predictions, exercise did not induce any deficit in selective response inhibition. Rather, the drop-off of the delta curve as reaction time lengthened suggested enhanced efficiency of cognitive processes in the first part of the exercise bout. Shortly before exhaustion, Cox values were severely reduced - though not characteristic of a hypofrontality state - while no sign of deficit in selective response inhibition was observed. Despite this, individual's susceptibility to making fast impulsive errors increased and less efficient online correction of incorrect activation was observed near exhaustion. A negative correlation between Cox values and error rate was observed and is discussed in terms of cerebral resources redistribution. (C) 2015 Elsevier Ltd. All rights reserved.

Background The net metabolic cost of walking (NCw) and the co-activation of leg muscles are both higher in old adults (OG) than in young adults (YG). Nevertheless, the relation between the two remains unresolved, mainly due to the controversial co-activation measurement method used in previous studies. Research question To compare ankle and knee co-contraction (CCI), calculated using an EMG-driven method, between the groups and to examine their relationship with NCw. Methods Nine young (YG = 25.2 +/- 3.3 years old) and nine older (OG = 68.7 +/5.9 years old) adults walked on a treadmill at five speeds (YG: 1; 1.2; 1.4; 1.6; 1.8 m/s; OG: 0.6; 0.8; 1; 1.2; 1.4 m/s) while electromyography (sEMG) and oxygen consumption were measured. CCI were calculated around the ankle and knee for different parts of the gait cycle (entire gait cycle 0–100 %, stance phase 0–60 %, swing phase 60–100 %). Results NCw was significantly higher (25 %, averaged over the walking speeds) in OG as were Knee_CCI, Knee_CCI_swing and Knee_CCI_stance. Multiple regression models in YG, OG and YG + OG highlighted Ankle_CCI as the main contributor in NCw (β = 0.08−0.188, p Significance The present findings provide a better understanding of the association between muscle co-contraction and metabolic cost in older adults. It may help scientists and clinicians to further develop strategies aimed at neuromuscular rehabilitation as a means of improving mobility and independence among older adults.

International audience; BACKGROUND: Transcranial magnetic stimulation (TMS) is a widely-used investigative technique in motor cortical evaluation. Recently, there has been a surge in TMS studies evaluating lower-limb fatigue. TMS intensity of 120-130% resting motor threshold (RMT) and 120% active motor threshold (AMT) and TMS intensity determined using stimulus-response curves during muscular contraction have been used in these studies. With the expansion of fatigue research in locomotion, the quadriceps femoris is increasingly of interest. It is important to select a stimulus intensity appropriate to evaluate the variables, including voluntary activation, being measured in this functionally important muscle group. This study assessed whether selected quadriceps TMS stimulus intensity determined by frequently employed methods is similar between methods and muscles. METHODS: Stimulus intensity in vastus lateralis, rectus femoris and vastus medialis muscles was determined by RMT, AMT (i.e. during brief voluntary contractions at 10% maximal voluntary force, MVC) and maximal motor-evoked potential (MEP) amplitude from stimulus-response curves during brief voluntary contractions at 10, 20 and 50% MVC at different stimulus intensities. RESULTS: Stimulus intensity determined from a 10% MVC stimulus-response curve and at 120 and 130% RMT was higher than stimulus intensity at 120% AMT (lowest) and from a 50% MVC stimulus-response curve (p < 0.05). Stimulus intensity from a 20% MVC stimulus-response curve was similar to 120% RMT and 50% MVC stimulus-response curve. Mean stimulus intensity for stimulus-response curves at 10, 20 and 50% MVC corresponded to approximately 135, 115 and 100% RMT and 180, 155 and 130% AMT, respectively. Selected stimulus intensity was similar between muscles for all methods (p > 0.05). CONCLUSIONS: Similar optimal stimulus intensity and maximal MEP amplitudes at 20 and 50% MVC and the minimal risk of residual fatigue at 20% MVC suggest that a 20% MVC stimulus-response curve is appropriate for determining TMS stimulus intensity in the quadriceps femoris. The higher selected stimulus intensities at 120-130% RMT have the potential to cause increased coactivation and discomfort and the lower stimulus intensity at 120% AMT may underestimate evoked responses. One muscle may also act as a surrogate in determining optimal quadriceps femoris stimulation intensity.

International audience; The role of sex stereotypes and gender roles in the sex differences observed in sport and exercise has been extensively investigated in sport psychology, past studies showing that stereotypes are internalized into the self during the socialization process. Although this research has provided clear evidence of the psychosocial roots of sex differences in athletics, focusing exclusively on an internalization explanation may not allow a complete understanding of the influence of stereotypes in this domain. This article presents two approaches that have been developed in mainstream psychology and discusses their relevance in sport psychology: (1) the situational approach, which considers that the mere presence of stereotypes in the environment is sufficient to affect individuals (e.g., stereotype threat theory); (2) the content of stereotypes approach (e.g., stereotype content model), which suggests that stereotypes about a particular group may be ambivalent, and that this ambivalence may serve to legitimize the status quo.

International audience; Aim: Examine the interest of progressive intermittent running test (15-15) entitled Spartacus to assess indirectly the global level of aerobic capacity of obese adolescents in comparison with the continuous Shuttle run test.Methods: Forty-three obese adolescents (33 girls and 10 boys) performed the two tests. Differences according to the “test”, “sex” and the interaction “test × sex” have been assessed for the maximum heart rate (HRmax), the final running speed, the total and net running durations and the perceived effort.Results and discussion: The results did not reveal any significant inter-test differences for FCmax and the perceived effort. As compared to the Shuttle run test, the Spartacus led to a 20% increased final running speed (11.5 vs. 9.4 km/h) and a 3.3 times longer total running duration (17.3 vs. 5.3 min) for a 1.7 times longer net exercise duration (8.7 vs. 5.3 min, P < 0.001). The results were neither significantly influenced by the “sex” nor by the “test × sex” interaction.Conclusion: The Spartacus intermittent test allowed obese adolescents to reach a similar psychophysiological state effort at the end of the run while producing an increased performance in both speed and duration.; Objectifs: Déterminer l’intérêt du test intermittent progressif de type 15-15 appelé Spartacus pour mesurer indirectement le niveau global de capacité aérobie d’adolescents obèses en le comparant au test continu Navette.Patients et méthodes: Quarante-trois adolescents obèses (33 filles et 10 garçons) ont réalisé les deux tests. L’influence du « type de test », du « sexe » et de leur interaction a été évaluée sur la fréquence cardiaque maximale (FCmax), la vitesse de fin de test, les durées totale de test et nette de course, et la difficulté perçue.Résultats: Les résultats ne montrent pas de différence significative inter-tests pour la FCmax et la difficulté perçue. Comparé au test Navette, le Spartacus permet d’obtenir une vitesse finale 20 % supérieure (11,5 vs. 9,4 km/h) et une durée totale de test 3,3 fois plus longue (17,3 vs. 5,3 min) pour une durée nette de course 1,7 fois supérieure (8,7 vs. 5,3 min) (p < 0,001). Il n’y a pas d’effets significatifs du « sexe » ni de l’interaction « type de test × sexe ».Conclusion: Le test Spartacus permet d’atteindre un même état psychophysiologique maximal en produisant une vitesse de course et une durée totale de test supérieures.

Resume Cet article vise a expliquer pourquoi dans le domaine sportif, considere traditionnellement comme un domaine masculin, les filles peuvent parfois recevoir de meilleurs traitements que les garcons. Nous avons examine si un tel contraste par rapport aux stereotypes reflete une remise en cause des stereotypes sexues traditionnels. Des enseignants d’education physique et sportive et des etudiants ont visionne des videos de performances en saut en longueur de filles et garcons. Nous leur avons demande de selectionner les cibles qu’ils jugeaient les meilleures pour faire partie de leur equipe (comportements zero-sum) et indiquer des reactions hypothetiques verbales et non verbales a l’encontre des cibles (comportements non-zero-sum). Chez les etudiants, comme chez les enseignants, un biais pro-fille a ete trouve dans les comportements non-zero-sum, alors que les comportements zero-sum ont revele un biais pro-garcon. Ce pattern illustre une conception ambivalente de l’influence des stereotypes. Il est interessant de noter que ces resultats ont ete obtenus avec des personnes cibles jouant successivement le role d’un garcon et le role d’une fille.

International audience; Recently, Elliot and Murayama (2008) pointed out a number of theoretical and methodological shortcomings among the instruments assumed to measure achievement goals. This research aimed to develop and validate a French Achievement Goals Questionnaire for Sport and Exercise (FAGQSE). In a first study, factor analyses conducted on a 20-item preliminary version supported the existence of four factors corresponding to the four types of goals of Elliot and McGregor's (2001) framework (mastery-approach, performance approach , mastery-avoidance, and performance-avoidance). A second study examined a more parsimonious 12-item version of the FAGQSE, which was found to be valid among samples of athletes, exercisers, and physical education students. The temporal stability of the questionnaire was evidenced by a satisfactory test-retest over a 1-month period, and its theoretical validity was supported by correlations between achievement goals and entity/incremental theories of sports ability, perceived sports competence, and sports anxiety. The FAGQSE is a valid and reliable French instrument for achievement goal motivation. This instrument can be used for theoretical and applied purposes in various sports and exercise settings.

International audience; In this research we examined the situational malleability of gender schema and specifically the association between competitive sport and masculinity at the intraindividual level. Based on Deaux and Major's (1987) interactive assumption, we predicted that a competitive sport context would activate the masculine dimension in gender schema. Participants were 64 French undergraduate students who evaluated themselves on the Bem Sex Role Inventory in general, in a competitive sport context, and in a cinema context. In addition to femininity and masculinity scores in each context, response latencies were also collected. The results indicated that participants responded higher and faster on masculine items when the competitive sport context was presented, showing that this association is well anchored in gender schema.

International audience; Objective: To assess whether Ramadan intermittent fasting (RIF) affects 5000m running performance and physiological parameters classically associated with middle distance performance.Design: Eighteen subjects (age 23.6±2.9 yr, body mass 64 ± 2.3 kg) divided in two experimental groups (Ramadan fasting (n = 9 vs. control, n= 9) participated in two experimental sessions, one before RIF and the other the last week of fasting.Setting: For each session subjects completed four tests in the same order: a maximal running test, a maximal voluntary contraction (MVC) of knee extensor, two rectangular submaximal exercises on treadmill of 6 min duration at an intensity corresponding to the first ventilatory threshold (VT1) and a running performance test (5000m).Participants: 18 well-trained middle distance runnersMain Outcome Measurements: Maximal oxygen consumption, maximal voluntary contraction, running performance, running efficiency submaximal VO2 kinetics parameters (basal VO2 : VO2b, time constant : τ, and amplitude : A1) and anthropometric parameters were recorded or calculated.Results: At the end of Ramadan fasting a decrease in maximal voluntary contraction was observed, (-3,2%, p< .00001, Eta2: 0.80), associated with an increase in time constant of oxygen kinetics (+51%, p< .00007, Eta2: 0.72) and a decrease in performance (-5%, p< .0007, Eta2: 0.51). No effect was observed on running efficiency or maximal aerobic power.Conclusions: These results suggest that Ramadan changes in muscular performance and oxygen kinetics could affect performance during middle distance events and need to be considered to choose training protocols during RIF.

International audience; Aim.- The purpose of this study was to analyze the effectiveness of supplementation in vitamin on the maximal muscular performance in master athletes during a strength training program.Method.- Twenty well-trained master athletes took part in a three weeks strength training program and in a same time in a micro nutritional supplementation program. Before and after the training period, blood markers of muscle damages were assessed. Before each training sessions maximal voluntary isometric strength was recorded. They were divided in two groups either with supplementation (Isoxan Force ®, Ao) or without (placebo, Pl).Results.- After the training period, knee extensor’s maximal voluntary strength significantly increased (+9,7% in Ao group vs. + 6,3% in Pl group ) in both groups. However, this increase was more pronounced in Ao group than in Pl group and recovery between training sessions was improved. Moreover significant difference in blood markers of muscle damages was found between groups at the end of the training program.Conclusion.- Results of this study confirm the benefits of a short period of strength training program on maximal muscular performance in master athletes. In all subjects, strength production capacity has significantly increased after the three weeks of training. Moreover the micro nutritional supplement is associated with a lower muscle inflammation suggesting an improvement of the beneficial effect of strength training with vitamin and mineral supplementation. .; Objectifs.- Le but de ce travail était d’étudier l’effet d’une stratégie de supplémentation en vitamines selon des doses et une composition correspondantes aux apports nutritionnels conseillés (ANC) pendant l’entraînement sur la variation de force maximale volontaire d’athlètes masters engagés dans un programme d’entraînement en force.Méthodes.- Vingt athlètes masters bien entraînés en endurance ont réalisé un programme d’entraînement en force des muscles extenseurs de la cuisse d’une durée de trois semaines. Avant et après la période d’entraînement, les marqueurs sanguins de l’inflammation musculaire ont été mesurés. Avant chaque séance d’entraînement la force maximale volontaire isométrique était testée. Ces sujets étaient divisés selon une méthode en double aveugle en deux groupes expérimentaux avec (groupe Ao) ou sans (groupe Pl) apport nutritionnel en vitamines et micro-nutriments, Isoxan Force®.Résultats.- A la suite de la période d’entraînement, la force maximale volontaire des muscles extenseurs de la cuisse a augmenté dans les deux groupes, (+9,7% pour le groupe Ao vs. + 6,3% pour le groupe Pl). Dans le groupe supplémenté l’amélioration est supérieure à celle du groupe placebo et la récupération entre les séances est améliorée. Enfin, en fin d’entrainement une différence significative des marqueurs sanguins des dommages et de l’inflammation musculaires est relevée entre les deux groupes.Conclusion.- Les résultats de cette étude confirment les bénéfices liés à une courte période d’entraînement en force sur la performance maximale musculaire chez des athlètes masters. Par ailleurs, l’apport micro nutritionnel pendant l’entraînement s’accompagne de dommages musculaires moins importants suggérant un effet de potentialisation des bénéfices de l’entrainement en force avec une supplementation en vitamines et minéraux.

International audience; compliance in divers exposed to repeated hyperoxia using rebreather equipment. Aviat Space Environ Med 2009; 80: 482 – 4. Background: Acute hyperoxic exposure is known to modify cardio-vascular parameters like a decrease in cardiac output, arterial vasocon-striction, and autonomic nervous system changes. We hypothesized that repeated hyperbaric hyperoxic exposures, as experienced by military oxygen divers, lead to long-term arterial alterations. Methods: Arterial blood pressure measurements and pulse wave velocity (PWV) recordings were performed during basal conditions in 15 elite military oxygen divers, and compared to 15 non-diver controls. The two groups were matched appropriately for physical characteristics (age: 35 6 5 yr, weight: 77 6 8 kg, height: 177 6 6 cm, body mass index: 24.6 6 2.0 kg z m 2 2), and aerobic capacity (V O 2 max : 52 6 7 ml z min 2 1 z kg 2 1). Results: No signifi cant difference was found in systolic blood pressure (120 6 11 mmHg), dia-stolic blood pressure (70 6 8 mmHg), or pulse pressure (50 6 7 mmHg). Furthermore, there was no signifi cant difference in the carotid-femoral PWV (6.7 6 0.9 m z s 2 1), the carotid-radial PWV (8.7 6 1.7 m z s 2 1), or the carotid-pedal PWV (8.1 6 1.1 m z s 2 1) between divers and controls. Conclusion: No difference in arterial compliance was observed in physically well-trained military oxygen divers in comparison with matched controls.

International audience; Background: The diving response includes cardiovascular adjustments known to decrease oxygen uptake and thus prolong apnea duration. As this diving response is in part characterized by a pronounced decrease in heart rate (HR), it is thought to be vagally mediated.Methods: In five professional breath-hold divers (BHDs) and fi ve less-trained controls (CTL), we investigated whether the diving response is in fact associated with an increase in the root mean square successive difference of the R-R intervals (RMSSD), a time-domain heart rate variability (HRV) index. HR behavior and arterial oxygen saturation (S a O 2) were continuously recorded during one maximal apnea. Short-term changes in S a O 2 , HR, and RMSSD were calculated over the complete apnea duration.Results: BHDs presented bi-phasic HR kinetics, with two HR decreases (32 6 17% and 20 6 10% of initial HR). The second HR decrease, which was concomitant to the pronounced S a O 2 decrease, was also simultaneous to a marked increase in RMSSD. CTL showed only one HR decrease (50 6 10% of initial HR), which appeared before the concomitant S a O 2 and RMSSD changes. When all subject data were combined, arterial desaturation was positively correlated with total apnea time (r 5 0.87, P , 0.01).Conclusion: This study indicates that barorefl ex stimulation and hypoxia may be involved in the bi-phasic HR response of BHDs and thus in their longer apnea duration.

Body sway was studied in standing with eyes closed during quiet breathing and apnoea. The hypothesis was that absence of ventilation improved balance. Performance and control of balance were assessed by centre of gravity and centre of pressure motions respectively. Eight healthy male subjects participated in the study. The analysis was performed for the first 20s when no activity of the diaphragm and no force variation at thoracic and abdominal levels were observed in apnoea condition. Performance and control were significantly improved in apnoea from 17 to 26% for the planar parameters; this improvement was only observed along the medio-lateral axis (around 34%), probably due to upper body asymmetry and diminution of the number of degrees of freedom that can be mobilised along this axis. In conclusion, ventilation in quiet breathing is a perturbing factor in human standing.

International audience

International audience; Policy is a powerful tool used to influence physical activity levels of populations. The World Health Organisation has specifically acknowledged the role of local governments in developing policies to promote Health-Enhancing Physical Activity (HEPA). However, scientific knowledge remains scant about the involvement of local governmental HEPA promotion policies. This scoping review aims to provide an overview of the scientific peer-reviewed literature emerging on local government policies promoting HEPA. Two researchers searched 7 databases to extract peer-reviewed research articles published in English between January 2006 and December 2018. A total of 28 articles were included; mainly from the USA (n = 15). Different types of HEPA policies, including those from local governments, were reported in this scoping review but they were usually not detailed enough to have a comprehensive overview of the aspects of interest for research and practice. Researchers used various methods in their studies; however, they were not systematically based on theoretical or conceptual frameworks. Findings extracted from articles in this scoping review indicated that inter-sectoral collaborations seemed to be a key factor to lead effective HEPA policies. Moreover, some specific local factors seemed to positively or negatively influence their development. Intensifying research on HEPA policies and in different contexts is now needed. Future research should be expanded to evaluate HEPA policies from adoption to implementation and maintenance and to evaluate health outcomes from such policies.

Context:Firefighters participating in mandatory physical exercise sessions are exposed to a high risk of ankle sprain injury. Although both physiological and psychological risk factors have been identified, few prospective studies considered the complex interaction of these factors in firefighters.Objective:To prospectively determine whether intrinsic physical risk factors and work-related environments predict ankle sprains occurring during on-duty physical exercise in firefighters during an 8-month follow-up period.Design:Prospective.Setting:Fire Department and Rescue Service.Participants:Thirty-nine firefighters were selected based on convenience sampling.Intervention:Participants performed physical tests and completed questionnaires.Main Outcome Measures:Lower Quarter Y-Balance Test, Weight-Bearing Lunge Test, anthropometric measures, postural stability, chronic ankle instability (Cumberland Ankle Instability Tool) scores, previous injuries, and perceived psychosocial work environment (Copenhagen Psychosocial Questionnaire [COPSOQ]).Results:During the follow-up, 9 firefighters sustained an injury. Lower Quarter Y-Balance Test and Weight-Bearing Lunge Test performances, Cumberland Ankle Instability Tool scores, history of previous ankle sprain, and specific dimensions of the COPSOQ significantly differed between injured and uninjured firefighters. Lower-limbs asymmetries of the Lower Quarter Y-Balance Test (ie, anterior, posteromedial, and posterolateral directions) and the Weight-Bearing Lunge Test were predictors of ankle sprains.Conclusions:These findings originally provide evidence that intrinsic factors mainly contribute to ankle sprains, although psychosocial work environment assessment could also characterize firefighters at risk.

International audience; Physiological signals present fluctuations that can be assessed from their temporal structure, also termed complexity. The complexity of a physiological signal is usually quantified using entropy estimators, such as Sample Entropy. Recent studies have shown a loss of force signal complexity with the development of neuromuscular fatigue. However, these studies did not consider the stationarity of the force signals which is an important prerequisite of Sample Entropy measurements. Here, we investigated the effect of the potential nonstationarity of force signals on the kinetics of neuromuscular fatigue-induced change in force signal's complexity. Eleven men performed submaximal intermittent isometric contractions of knee extensors until exhaustion. Neuromuscular fatigue was assessed from changes in voluntary and electrically evoked contractions. Sample Entropy values were computed from submaximal force signals throughout the fatiguing task. The Dickey-Fuller test was used to statistically investigate the stationarity of force signals and the Empirical Mode Decomposition was applied to detrend these signals. Maximal voluntary force, central voluntary activation and muscle twitch decreased throughout the task (all p < 0.05), indicating the development of global, central and peripheral fatigue, respectively. We found an increase in Sample Entropy with fatigue (p = 0.024) when not considering the nonstationarity of force signals (i.e. 43% of the signals). After applying the Empirical Mode Decomposition, we found a decrease in Sample Entropy with fatigue (p = 0.002). These findings confirm the presence of nonstationarity in force signals during submaximal isometric contractions which influences the kinetics of change in Sample Entropy with neuromuscular fatigue.

International audience; Purpose: The purpose of this study was to investigate the influence of different cycling cadences on metabolic and kinematic parameters during subsequent running.Methods: Eight triathletes performed two incremental tests (running and cycling) to determine maximal oxygen uptake (V̇O2max) and ventilatory threshold (VT) values, a cycling test to assess the energetically optimal cadence (EOC), three cycle-run succession sessions (C-R, 30-min cycle + 15-min run), and one 45-min isolated run (IR). EOC, C-R, and IR sessions were realized at an intensity corresponding to VT + 5%. During the cycling bouts of C-R sessions, subjects had to maintain one of the three pedaling cadences corresponding to the EOC (72.5 ± 4.6 rpm), the freely chosen cadence (FCC; 81.2 ± 7.2 rpm), and the theoretical mechanical optimal cadence (MOC, 90 rpm; Neptune and Hull, 1999).Results: Oxygen uptake (V̇O2) increased during the 30-min cycling only at MOC (+12.0%) and FCC (+10.4%). During the running periods of C-R sessions, V̇O2, minute ventilation, and stride-rate values were significantly higher than during the IR session (respectively, +11.7%, +15.7%, and +7.2%). Furthermore, a significant effect of cycling cadence was found on V̇O2 variability during the 15-min subsequent run only for MOC (+4.1%) and FCC (+3.6%).Conclusion; The highest cycling cadences (MOC, FCC) contribute to an increase in energy cost during cycling and the appearance of a V̇O2 slow component during subsequent running, whereas cycling at EOC leads to a stability in energy cost of locomotion with exercise duration. Several hypotheses are proposed to explain these results such as changes in fiber recruitment or hemodynamic modifications during prolonged exercise.

Background The drive for muscularity behaviors are very common in male athletes, especially in male bodybuilders. Studies have related drive for muscularity behaviors to body dissatisfaction, eating disorders and muscle dysmorphia. Methods This study applied the trans-contextual model of motivation to the drive for muscularity behaviors of male bodybuilders at risk of developing muscle dysmorphia. The relationships between self-determination theory constructs and drive for muscularity behaviors, via the theory of planned behavior variables (i.e., attitude, subjective norm, perceived behavioral control, and intention) were examined. A total of 175 Swiss male bodybuilders (Mage = 27.34; SDage = 7.53) completed measures on motivation for sport, theory of planned behavior variables, and drive for muscularity behaviors. They practiced bodybuilding from three to 24 h per week (Mhours per week = 6.59; SDhours per week = 3.45) and had done so for 7.19 years on average (SDnumber of years = 6.91). Using bootstrapped maximum likelihood estimation with the AMOS 7.0 program, a series of confirmatory factor analyses was performed on each subscale and a series of path analyses was performed to determine the final model. Results The fit indices of the final model were satisfactory: χ2 (11) = 13.81; p = .244; TLI = .98; CFI = .99; RMSEA = .04. The model explained 29% of the variance of drive for muscularity behaviors. The final path analysis supported the motivational sequence, with autonomous motivation for sport showing a positive, significant and indirect association with the drive for muscularity behaviors via perceived behavioral control and intention to gain muscle mass, and controlled motivation for sport showing a positive association with the drive for muscularity behaviors both directly and via attitude and intention to gain muscle mass. Conclusions It was concluded that the trans-contextual model of motivation applies only partially to the drive for muscularity behaviors in male bodybuilders. Perspective The motivational mechanisms explaining the development of drive for muscularity behaviors might be better understood through complementary analyses of motivational profiles. Such investigations would guide the design of programs to lower the risks associated with these behaviors.

ObjectiveTo report the prevalence of lower airway dysfunction in athletes and highlight risk factors and susceptible groups.DesignSystematic review and meta-analysis.Data sourcesPubMed, EBSCOhost and Web of Science (1 January 1990 to 31 July 2020).Eligibility criteriaOriginal full-text studies, including male or female athletes/physically active individuals/military personnel (aged 15–65 years) who had a prior asthma diagnosis and/or underwent screening for lower airway dysfunction via self-report (ie, patient recall or questionnaires) or objective testing (ie, direct or indirect bronchial provocation challenge).ResultsIn total, 1284 studies were identified. Of these, 64 studies (n=37 643 athletes) from over 21 countries (81.3% European and North America) were included. The prevalence of lower airway dysfunction was 21.8% (95% CI 18.8% to 25.0%) and has remained stable over the past 30 years. The highest prevalence was observed in elite endurance athletes at 25.1% (95% CI 20.0% to 30.5%) (Q=293, I2=91%), those participating in aquatic (39.9%) (95% CI 23.4% to 57.1%) and winter-based sports (29.5%) (95% CI 22.5% to 36.8%). In studies that employed objective testing, the highest prevalence was observed in studies using direct bronchial provocation (32.8%) (95% CI 19.3% to 47.2%). A high degree of heterogeneity was observed between studies (I2=98%).ConclusionLower airway dysfunction affects approximately one in five athletes, with the highest prevalence observed in those participating in elite endurance, aquatic and winter-based sporting disciplines. Further longitudinal, multicentre studies addressing causality (ie, training status/dose–response relationship) and evaluating preventative strategies to mitigate against the development of lower airway dysfunction remain an important priority for future research.

Head-out water immersion alters respiratory compliance which underpins defining pressure at a “Lung centroid” and the breathing “Static Lung Load”. In diving medicine as in designing dive-breathing devices a single value of lung centroid pressure is presumed as everyone’s standard. On the contrary, we considered that immersed respiratory compliance is disparate among a homogenous adult group (young, healthy, sporty). We wanted to substantiate this ample scattering for two reasons: (i) it may question the European standard used in designing dive-breathing devices; (ii) it may contribute to understand the diverse individual figures of immersed work of breathing. Resting spirometric measurements of lung volumes and the pressure–volume curve of the respiratory system were assessed for 18 subjects in two body positions (upright Up, and supine Sup). Measurements were taken in air (Air) and with subjects immersed up to the sternal notch (Imm). Compliance of the respiratory system (Crs) was calculated from pressure–volume curves for each condition. A median 60.45% reduction in Crs was recorded between Up-Air and Up-Imm (1.68 vs 0.66 L/kPa), with individual reductions ranging from 16.8 to 82.7%. We hypothesize that the previously disregarded scattering of immersion-reduced respiratory compliance might participate to substantial differences in immersed work of breathing.

Breathing through inspiratory or expiratory resistive loads activates respiratory afferents. In healthy individuals, we explored the recruitment of motor units in arm (adductor pollicis, AP and biceps branchialis, BB) and leg (vastus lateralis, VL) muscle groups during voluntary contractions sustained at 80% of maximal force. Quantitative EMG analysis consisted of measurement of energies in high (EH) and low (EL) frequency bands. EH and EL changes were measured at constant time, i.e. 10 and 20 s after the onset of plateau contraction. The resistive load was added to the inspiratory or the expiratory circuit for 10-min periods. Its value was high but not enough to induce changes in blood gases and blood pressure. Compared to muscle contractions performed during non-loaded breathing periods, inspiratory loading did not affect BB and VL contractions, whereas it induced significant changes in AP contraction, characterized by enhanced variations in EL value measured at 10 s. Expiratory loading affected solely the VP contraction. Then, EH decreased at 10 and 20 s while it increased always when VP contractions were executed during non-loaded breathing. Expiratory loading elevated the functional residual capacity (FRC), but the load-induced changes in VL contraction persisted when subjects adjusted their FRC to the control level. These data suggest that respiratory afferents influence the skeleto-motor drive. Thus, viscero-somatic reflex may be present in patients with severe obstructive pulmonary disease.

International audience; Female athletes have garnered considerable attention in the last few years as more and more women participate in sports events. However, despite the well-known repercussions of female sex hormones, few studies have investigated the specificities of elite female athletes. In this review, we present the current but still limited data on how normal menstrual phases, altered menstrual phases, and hormonal contraception affect both physical and cognitive performances in these elite athletes. To examine the implicated mechanisms, as well as the potential performances and health risks in this population, we then take a broader multidisciplinary approach and report on the causal/reciprocal relationships between hormonal status and mental and physical health in young (18–40 years) healthy females, both trained and untrained. We thus cover the research on both physiological and psychological variables, as well as on the Athlete Biological Passport used for anti-doping purposes. We consider the fairly frequent discrepancies and summarize the current knowledge in this new field of interest. Last, we conclude with some practical guidelines for eliciting improvements in physical and cognitive performance while minimizing the health risks for female athletes.

Purpose. Inducing a negative stereotype toward women usually leads to a decrease in women performance and an increase in men performance. These effects were observed during technical tasks. The pur...

Three-dimensional gait analysis is the gold standard for gait-assessment in patients with stroke. This technique is commonly used to assess the effect of treatment on gait parameters. In clinical practice, three gait analyses are usually carried out (baseline, after treatment and follow-up), the objectives were to define the reproducibility and the Minimum Detectable Change (MDC) for gait parameters in stance and swing measured using 3D-gait analysis, and to assess changes in MDC across three repeated 3D-gait analyses. Three gait analyses (V1, V2 and V3) were performed at 7-day intervals in twenty-six patients with chronic stroke. Kinematic data (in the sagittal plane, during swing and stance) and spatiotemporal data were evaluated for the paretic limb. Reliability was tested using repeated measures ANOVA with a Tukey post hoc test, and the MDC values were calculated for each parameter. Only the range of hip motion during swing changed significantly between V1 and V2, but no other kinematic parameters changed. No significant differences were observed for the spatiotemporal parameters. MDC values were always higher during the V1vsV2 comparison for both kinematic and spatiotemporal parameters. This is the first study to evaluate the MDC for kinematic and spatiotemporal parameters during stance and swing. Reliability of kinematic and spatiotemporal data across sessions was very good over the three sessions. MDC values were the lowest between V2 and V3 for most parameters. Use of the MDC will allow clinicians to more accurately determine the effect of treatments.

Although aquabiking has become widespread, the assessment of the intensity for aquatic cycling remains poorly defined.This study investigated the validity of differentiated ratings of perceived exertion (dRPE) recorded from the chest (RPE-chest) and legs (RPE-legs) during aquatic cycling and aimed to determine a simple and accurate estimate of dRPE to regulate aquabiking. Twelve active young subjects performed a pedaling task on an immersed ergocycle using randomly imposed cycling cadences ranging from 50 to 100 rpm in 3-minute steps interspersed by 3-minute active recovery periods. dRPE and cardiorespiratory responses (heart rate [HR]; percentage of heart rate peak value [%HRinfpeak/inf]; oxygen uptake [V̇Oinf2/inf]inf;/infand percentage of peak oxygen uptake [%V̇Oinf2peak/inf]) were measured during the last minute of each level.The data described three-step relationships between dRPE and rpm. RPE-chest and RPE-legs increased linearly only for cadences between 60 and 90 rpm (r=0.81 and r=0.88, respectively; P0.001). At these cadences, significant relationships were also observed between dRPE and all the physiological data (highest Pearson product moment for %V̇Oinf2peak/inf: 0.81 for RPE-chest and 0.88 for RPE-legs, P0.0001). Last, the classic signal dominance from the legs was observed (RPE-legsRPE-chest, P0.0001) but was reduced compared with data obtained during dryland cycling, suggesting a modulating effect of the aquatic medium.Cycling cadence was the better estimator of RPE-legs, which seemed to be the more appropriate dRPE to regulate the intensity of aquabiking in a safe range of pedaling rates.

Purpose: This study aims to analyze learning differences between synchronous and asynchronous propulsion mode in manual wheelchairs.Materials and methods: Twenty novice and abled-bodied subjects (19.9 ± 1.3 years, 65.4 ± 8.8 kg, 173.6 ± 6.5 cm) participated in this study. Two sprints, in synchronous and asynchronous conditions, before and after twelve hours of sport practice including the learning of these two modes of propulsion, were realized. The rate of increase of the total force when entering the handrail, cadence, total and tangential force, speed and power were measured.Results: Significant differences before and after the twelve hours of practice are highlighted for speed (P < 0.0001), power (P = 0.006), rate of increase in total force (P = 0.02) and the tangential force (P = 0.005). The ANOVA performed also shows significant differences for the total force (P = 0.01), the velocity (P = 0.0002), the power (P = 0.002) and the tangential force (P = 0.005) between asynchronous and synchronous. Statistical analysis shows no significant interaction. The measured parameters tend to increase more significantly for the asynchronous vs. synchronous mode.Conclusion: The learning of the two modes of propulsion had significant effects on the main parameter of propulsive performance, speed. However, two of the biomechanical parameters related to the risk of injury, the rate of increase of the total force and the total force, increase significantly for the two modes of propulsion. It would be interesting to propose adapted muscle strengthening sessions during the learning phase. In addition, evolution percentages tend to be higher in asynchronous vs. synchronous propulsion. These results suggest that asynchronous instruction should be favored early on in the learning of manual wheelchair basketball., Objectifs: Cette étude vise à analyser les différences d’apprentissage existantes entre le mode de propulsion synchrone et asynchrone en fauteuil roulant manuel.Matériels et méthode: Vingt sujets valides novices (19,9 ± 1,3 ans ; 65,4 ± 8,8 kg ; 173,6 ± 6,5 cm) ont pris part à cette étude. Deux sprints, en conditions synchrone et asynchrone, avant et après douze heures de pratique sportive incluant l’apprentissage de ces deux modes de propulsion, ont été réalisés. Le taux d’augmentation de la force totale lors de la saisie de la main courante, la cadence, la force totale et tangentielle, la vitesse et la puissance ont été mesurés.Résultats: Des différences significatives avant et après les douze heures de pratique sont mises en évidence pour la vitesse (p < 0,0001), la puissance (p = 0,006), le taux d’augmentation de la force totale (p = 0,02) et la force tangentielle (p = 0,005). L’Anova réalisée montre également des différences significatives pour la force totale (p = 0,01), la vitesse (p = 0,0002), la puissance (p = 0,002) et la force tangentielle (p = 0,005) entre asynchrone et synchrone. L’analyse statistique ne montre pas d’interaction significative. Les paramètres mesurés tendent à augmenter de manière plus importante pour le mode asynchrone vs synchrone.Conclusion: L’apprentissage des deux modes de propulsion a eu des effets significatifs sur le principal paramètre de performance propulsive, la vitesse. Or, deux des paramètres biomécaniques liés aux risques de blessures, le taux d’augmentation de la force totale et la force totale, augmentent significativement pour les deux modes de propulsion. Il serait alors intéressant de proposer des séances de renforcement musculaire adaptées durant la phase d’apprentissage. De plus, les pourcentages d’évolution tendent à être plus importants en propulsion asynchrone vs synchrone. Ces résultats amènent à penser qu’il faudrait privilégier l’enseignement asynchrone de manière précoce durant l’apprentissage du basket en fauteuil roulant manuel.

People living with HIV (PLHIV) are not physically active enough. As nonexercisers are perceived as less healthy, less active and less strong, it is likely that PLHIV would be subject to a nonexerciser stereotype threat. We looked to elucidate the effect of the emerging nonexerciser stereotype on handgrip strength performance among less active PLHIV. We also sought to observe the modulating role of self-efficacy in the relationship between stereotype activation and performance.Eighteen PLHIV were recruited to participate in two experimental sessions in which both a stereotypical context and self-efficacy were manipulated. Participants performed a handgrip task comprising a 15-s fatiguing maximal voluntary isometric contraction (MVC) exercise preceded (Pre) and followed (Post) by 5-s MVCs. In each session, (i.e. high and low self-efficacy), four experimental conditions (i.e. Control 1; Control 2; Stereotypical; Self-Efficacy) were performed.A significant performance decrease of the 15-s fatiguing MVC exercise was systematically observed when the nonexerciser stereotype was induced (0.01

The practice of the wheelchair rugby is becoming more and more worldwide. However, few biomechanical studies have focused on this sport. The aim of this study was to compare kinematic parameters of wheelchair rugby players, classified as defensive players (LP-D) versus offensive players (HP-O). Twenty-nine wheelchair rugby players (17 LP-D and 12 HP-O) performed a 20-m sprint test. The peak velocities, temporal parameters (propulsion phase time, deceleration phase time, cycle time and cycle frequencies) and asymmetries (the difference in peak velocities between the right and the left wheels) were measured at the acceleration and constant peak velocity phases of the sprint by an inertial measurement unit which was placed on each rear wheel. At the acceleration and constant peak velocity phases, peak velocities and cycle frequencies were higher in HP-O players than LP-D players. The deceleration phase times and the cycle times were higher in LP-D players than HP-O players. However, no significant difference in asymmetry was found between LP-D players and HP-O players. The HP-O players showed superior performance than the LP-D players, but they could be more exposed at risk of injury at their upper limbs than LP-D players.

Context: Drop jumps and high-intensity interval running are relevant training methods to improve explosiveness and endurance performance, respectively. Combined training effects might, however, be achieved by performing interval drop jumping. Purpose: To determine the acute effects of interval drop jumping on oxygen uptake ()—index of cardioventilatory/oxidative stimulation level and peripheral fatigue—a limiting factor of explosiveness. Methods: Thirteen participants performed three 11-minute interval training sessions during which they ran 15 seconds at 120% of the velocity that elicited maximal () (ITrun), or drop jumped at 7 (ITDJ7) or 9 (ITDJ9) jumps per 15 seconds, interspersed with 15 seconds of passive recovery. and the time spent above 90% of () were collected. Peripheral fatigue was quantified via preexercise to postexercise changes in evoked potentiated quadriceps twitch (ΔQT). Power output was estimated during ITDJs using optical sensors. Results: All participants reached 90% of or higher during ITrun and ITDJ9, but only 11 did during ITDJ7. was not different between ITrun and ITDJ9 (145 [76] vs 141 [151] s; P = .92) but was reduced during ITDJ7 (28 [26] s; P = .002). Mean ΔQT in ITDJ9 and ITDJ7 was not different (−17% [9%] vs −14% [8%]; P = .73) and greater than in ITrun (−8% [7%]; P = .001). No alteration in power output was found during ITDJs (37 [10] W·kg−1). Conclusion: Interval drop jumping at a high work rate stimulated the cardioventilatory and oxidative systems to the same extent as interval running, while the exercise-induced increase in fatigue did not compromise drop jump performance. Interval drop jumping might be a relevant strategy to get concomitant improvements in endurance and explosive performance.

The present research investigated the effect of the induction of a negative stereotype on older adults’ performance during an endurance task, and how this stereotype influenced older adults’ subjective age. Thirty-four old women were randomly assigned to one of the two conditions: a negative stereotype condition and a nullified-stereotype condition. They performed an endurance task consisting of maintaining 30% of their maximal strength, as long as possible. Then, they answered a questionnaire including subjective age measurement. Contrary to expectations, the induction of the negative stereotype did not influence participants’ endurance performance. However, participants in the negative stereotype condition felt older than participants in the nullified-stereotype condition. As subjective age is relevant to late-life health outcomes, such as walking speed or mortality risk, it seems necessary to implement some strategies to decrease the negative effect of the negative stereotype on subjective age.

Both doping (e.g. Hodge, K., Hargreaves, E. A., Gerrard, D. F., & Lonsdale, C. (2013). Psychological mechanisms underlying doping attitudes in sport: Motivation and moral disengagement. Journal of Sport and Exercise Psychology, 35, 419-432.) and eating behaviours (e.g. Hagger, M. S., Chatzisarantis, N. L., & Harris, J. (2006). From psychological need satisfaction to intentional behaviour: Testing a motivational sequence in two behavioural contexts. Personality and Social Psychology Bulletin, 32, 131-148.) have been studied independently within the SDT framework, but no research has examined these variables concomitantly to better understand the relationships between motivation for sport and doping variables. We therefore examined the mediating role of eating behaviour in the relationship between SDT constructs for sport motivation and athletes' susceptibility to doping. Bootstrapped mediation analyses were performed for 171 male and female athletes with competitive experience in various sports. The analyses revealed that healthy eating behaviours significantly mediated the relationship between SDT motivational constructs and susceptibility to doping. The findings enrich our theoretical understanding of how the SDT approach to motivation for sport might provide insight into the susceptibility to doping; that is, through the potential mediating role of healthy eating behaviours. Finally, the potential central position of eating behaviours in the motivation-doping relationship opens up a potential swathe of novel research, with investigations into eating behaviours at the forefront of future research on the psychology of doping.

Objective: Health promotion in sports clubs is receiving increased attention, but its benefits have not been widely evaluated for two reasons: (1) the difficulty in measuring ecological approach outcomes and (2) the existing literature having focused more on coaches’ efficiency rather than on health promotion. This article analyses the relationship between coaches’ health promotion activities, sports experience and health among adult sports participants. Design: A cross-sectional study using self-reported measurement among 204 adult sports participants ( Mage = 49.05). A questionnaire measuring demographics, coaches’ health promotion activities (healthy lifestyle, substance use and respect for oneself and others), sports experience (enjoyment, subjective vitality) and health (perceived health and quality of life, self-esteem) was completed either before or after a training session. Setting: Sixteen sports clubs in France Method: Multilevel analyses were used to evaluate the relationships between health promotion, sports experience and health outcomes, while t-tests compared differences between male adult and youth samples. Results: Adult perceptions of coaches’ health promotion activities were linked to enjoyment, perceived health and subjective vitality. The topic ‘healthy lifestyle’ was related to enjoyment and perceived health among adults. The topic ‘respect for oneself and others’ was related to self-esteem. Conclusion: Adult and youth perceptions of coaches’ health promotion activities vary and are linked to different health outcomes. More research is needed to better identify the benefits of health promotion in sports clubs for sports participants, including longitudinal studies to explore causal relationships between variables.

Background When landing from a jump or a drop, muscles contract before touchdown to anticipate imminent collision with the ground, soften ground contact and allow to return to a stable standing position without stepping or rebounding. Research question This study assesses the effect of the unsteadiness of the environment on the motor control of landing. The ‘unsteady environment’ was induced by asking participants to perform drop landings inside an aircraft that underwent trajectories parallel to Earth’s surface. The participants also performed the same task in a ‘steady environment’ in our laboratory. Methods Ground reaction forces, lower limb joints’ movements and the activity of lower limb muscles were recorded. The stability of the landing was assessed by the vertical and anterior-posterior stability indexes, center of pressure measures and by the coefficient of variation of kinetic and kinematic parameters. Results On one hand, participants slowdown their joint movements and reduce the knee joint excursion during landing, probably to avoid excessive movements that may induce imbalance. On the other hand, the stability of the landing is reduced while the variability of the movement is increased, illustrating a less stable and less consistent landing. In addition, whatever the environment, landing parameters associated with increased stiffness (i.e., increased impact forces and decreased joint range of motion) are correlated with decreased landing stability. Significance Overall, landings in the‘unsteady environment’ appear to be more cautious but less stable and less finely tuned. Since the stability of the landing is not directly influenced by the steadiness of the environment, this more cautious behavior could be, at least in part, related to the fear/apprehension induced by sudden acceleration variations of the frame of the aircraft.

Background Muscle weakness in patients with chronic stroke is due to neuromuscular disorders such as muscle atrophy, loss of voluntary activation or weak muscle contractile properties which are majored by the imbalance of interhemispheric inhibition following stroke. In patients with chronic stroke, unilateral transcranial direct current stimulation improved the maximal isometric strength of paretic knee extensors, but bilateral transcranial direct current stimulation failed to improve concentric strength. This study aimed to assess if a bilateral current stimulation improves isometric maximal strength, voluntary activation and contractile properties of knee extensors in patients with chronic stroke. Methods Thirteen patients with chronic stroke and eight young healthy individuals participated in this randomized, simple-blinded, crossover study that included two experimental sessions: one with sham bilateral transcranial direct current stimulation and another with effective bilateral transcranial direct current stimulation (20 min, 2 mA). In the stroke patients, the anode was placed over the primary motor cortex of the affected hemisphere and the cathode over the contralateral primary motor cortex. In healthy participants, the brain side targeted by the anode and the cathode was randomly assigned. In each session, participants performed three assessments of strength, voluntary activation and contractile properties: before, during and after effective/sham bilateral transcranial direct current stimulation. Findings Bilateral transcranial direct current stimulation had no effect on any neuromuscular assessments in both groups (All P values > 0.05, partial eta-squares varied from 0.02 to 0.06). Interpretation A single session of bilateral transcranial direct current stimulation did not compensate muscular weakness of knee extensors in patients with chronic stroke.

Velocity strength training requires exercise modalities that allow athletes to reach very high movement velocity, which is limited during vertical movements involving body weight. Purpose: To quantify the mechanical outputs developed during horizontal squat jumps (HSJs), notably the movement velocity, in comparison with vertical squat jumps (SJs) with and without loads. Methods: Thirteen healthy male athletes performed SJs without additional loads (SJ0) and with a load of ∼60% of body mass (SJ60), and during HSJs performed lying on a roller device with (assisted HSJ [AHSJ]) and without (HSJ) rubber-band assistance. Instantaneous lower-limb extension velocity, force, and power output were measured and averaged over the push-off phase. Results: The force was significantly higher during SJ60 than during SJ0, which was higher than during HSJ and AHSJ. Extension velocity was significantly different across all conditions, with 0.86 (0.07), 1.29 (0.10), 1.59 (0.19), and 1.83 (0.19) m·s−1 for SJ60, SJ0, HSJ, and AHSJ conditions, respectively. Differences in force and velocity values between SJ0 and the other conditions were large to extremely large. Differences were observed in power values only between SJ60 and SJ0, SJ60 and AHSJ, and SJ0 and HSJ. Conclusions: HSJ modalities allow athletes to reach very to extremely largely greater lower-limb extension velocities (HSJ +24.0% [16%], AHSJ +42.8% [17.4%]) compared to those achieved during SJ0. HSJ and AHSJ modalities are inexpensive and practical modalities to train limb-extension velocity capabilities, that is, the ability of the neuromuscular system to produce force at high contraction velocities.

Delextrat, A, Gruet, M, and Bieuzen, F. Effects of small-sided games and high-intensity interval training on aerobic and repeated sprint performance and peripheral muscle oxygenation changes in elite junior basketball players. J Strength Cond Res 32(7): 1882-1891, 2018-The aim of the current study was to compare the effects of 6 weeks of small-sided game (SSG) and high-intensity interval training (HIIT) on aerobic fitness and muscle oxygenation during a repeated sprint (RS) sequence in elite male junior basketball players. Twenty participants (14.3 ± 0.5 years; 176.8 ± 12.5 cm; 74.5 ± 9.8 kg) performed pre- and post-tests interspersed by 6 weeks of SSG or HIIT training. Testing sessions consisted of the 30-15 intermittent fitness test and an RS sequence (2 bouts of 15 seconds). During RS, muscle oxygenation parameters (tissue saturation index [TSI, %], postsprint muscle reoxygenation rate) were measured using near-infrared spectroscopy. The results showed that both training interventions similarly improved maximal aerobic speed (VIFT, 3.4 and 4.1%, respectively, for HIIT and SSG, P < 0.05) as well as RS ability (smaller percentage decrement by 62.5 and 21.6%, respectively, for HIIT and SSG, P < 0.05). Both training interventions also resulted in a greater ΔTSI during the second sprint (47.8-114%, P < 0.05) and significant improvements in postsprint reoxygenation after both sprints (+23.0 to +107.7%). Finally, the variation in muscle reoxygenation after sprint 1 was significantly associated with improvements in aerobic (ΔVIFT, r = 0.61, P = 0.008) and anaerobic (Δ% Dec during RS, r = -0.487, P = 0.028) performances. The current study has observed that SSG and HIIT resulted in similar improvements in aerobic and anaerobic variables and a better muscle oxygenation capacity during RS. Coaches should be aware that both trainings are applicable methodologies to improve in-season aerobic and anaerobic fitness capacities in junior basketball players.

Background Lower limb muscle strength is an important determinant of physical function in older adults. However, its measure in clinical settings is limited because of the requirement for large-scale and costly equipment. A new simple protocol based on sit-to-stand test (STS) is developed to measure force velocity (F-v) and power velocity (P-v) profile in the community-dwelling older adults. Objective The objective of this study was to assess the validity of this new methodology for measuring F-v and P-v profile compared to the gold standard isokinetic BIODEX. Participants 46 older people aged 65–85 years (M = 73.7; SD = 7.7). Methods F-v and P-v profiles were assessed in participants on their dominant leg. The concurrent validity of STS was tested using Spearman's rank correlation coefficient and Passing Bablok: maximal power output Pmax, optimal velocity and force Vopt and Fopt, maximal force at null velocity F0, maximal unloaded velocity V0 and coefficient of F-v (SFV) and P-v equation (a_poly, b_poly). Results No proportional difference for F0 and b_poly and a low significant correlation for Pmax (r = 0.314), Sfv (r = 0.229), a_poly (r = 0.335) and b_poly (r = 0.226) whereas the other parameters were non correlated significantly. Conclusion STS method is moderately reliable on force and power parameters whereas further improvements are needing for velocity parameters. However, its feasibility, portability and lower cost compared to other methods makes it very affordable in clinical context and will allow easy investigation of aging population.

Purpose:To compare the sensitivity of a sprint vs a countermovement-jump (CMJ) test after an intense training session in international rugby sevens players, as well as analyze the effects of fatigue on sprint acceleration.Methods:Thirteen international rugby sevens players completed two 30-m sprints and a set of 4 repetitions of CMJ before and after a highly demanding rugby sevens training session.Results:Change in CMJ height was unclear (–3.6%; ±90% confidence limits 11.9%. Chances of a true positive/trivial/negative change: 24/10/66%), while a very likely small increase in 30-m sprint time was observed (1.0%; ±0.7%, 96/3/1%). A very likely small decrease in the maximum horizontal theoretical velocity (V0) (–2.4; ±1.8%, 1/4/95%) was observed. A very large correlation (r = –.79 ± .23) between the variations of V0 and 30-m-sprint performance was also observed. Changes in 30-m sprint time were negatively and very largely correlated with the distance covered above the maximal aerobic speed (r = –.71 ± .32).Conclusions:The CMJ test appears to be less sensitive than the sprint test, which casts doubts on the usefulness of a vertical-jump test in sports such as rugby that mainly involve horizontal motions. The decline in sprint performance relates more to a decrease in velocity than in force capability and is correlated with the distance covered at high intensity.