Journal articles on the topic 'Exercices physiques – Physiologie'

De nombreuses études épidémiologiques confirment les bienfaits procurés par l’activité physique en ce qui concerne la diminution du risque de maladie associée à l’âge et de la mortalité quelle qu’en soit la cause. L’analyse de la littérature scientifique centrée sur les caractéristiques principales (intensité, type, quantité) montre que la quantité nécessaire d’activité physique est celle qui améliore la condition cardiorespiratoire, la force musculaire, la puissance et, indirectement, l’équilibre. L’appauvrissement de ces fonctions avec l’âge entraîne des limitations physiques qui conditionnent les activités fonctionnelles journalières. En revanche, un programme d’activité physique peut atténuer ces pertes, évitant ainsi aux personnes âgées (plus de 65 ans) de traverser le seuil de l’incapacité physique. Les études transversales et longitudinales révèlent un lien entre la condition cardiorespiratoire et la capacité fonctionnelle et l’autonomie ; la force musculaire et par surcroît, la puissance musculaire, permettent d’accomplir plus efficacement les activités de tous les jours ; l’équilibre dynamique en combinaison avec la puissance musculaire forment un ensemble de prévention contre les chutes. D’après les études sur les programmes d’intervention, les personnes âgées peuvent améliorer leurs capacités fonctionnelles car elles possèdent la capacité d’adaptation à l’entraînement physique. Les quelques études qui ont analysé les quantités minimale et optimale d’activité physique indiquent qu’il faut faire des exercices dans les plages d’intensité modérée à vigoureuse si on veut atteindre et préserver les gains résultant de la pratique régulière. Par conséquent, on devrait prescrire des activités physiques en spécifiant le type d’activité qui améliorera les variables organiques associées au maintien de la capacité fonctionnelle et de l’autonomie et, de ce fait, on repoussera la maladie et la mort. Une bonne recommandation concernant l’exercice physique chez les personnes âgées devrait inclure des activités cardiorespiratoires modérément vigoureuses (la marche rapide), un entraînement à la force et à la puissance pour la préservation de la masse musculaire et de la capacité de travail de groupes musculaires choisis et des exercices d’équilibre et d’étirement au besoin.

An Examination of Social Physique Anxiety with Regard to Sex and Level of Sport InvolvementThe primary purpose of this study was to investigate the difference in social physique anxiety among competitive athletes, exercisers and non-exercisers. The present study was also aimed to examine the sex differences in social physique anxiety between men and women. Two hundred and fifty-five exercisers, 261 competitive athletes and 350 non-exercisers voluntarily participated in this study. Social Physique Anxiety Scale (Hart, Leary and Rejeski, 1989) was used as the measure of social physique anxiety. Results of the present study indicated significant differences in social physique anxiety with regard to sex and level of sport involvement. Men had lower scores on social physique anxiety than women, and competitive athletes and exercisers had lower social physique anxiety scores than non-exercisers. Social physique anxiety of males and females did not differ with regard to level of sport involvement.

Comment l’expérience peut-elle mener à une éducation corporelle ? Une expérience sans conscience n’est pas seulement ruine de l’âme mais épuisement du corps faute d’une science réflexive constituée. Mais laquelle ? La phénoménologie a cru pouvoir réduire le vivant au vécu de la conscience avant de devoir reconnaître les difficultés d’une esthésiologie purement subjective et transcendantale. Dewey reconnaît à la physiologie de l’organisme vivant une matière suffisante pour nous indiquer par l’instinct, la fatigue, l’effort, l’habitude, le développement et la croissance des informations dont la conscience devrait s’emparer pour modifier les conditions de notre existence. L’éducation corporelle, à la différence de l’éducation physique, est dans l’usage que nous faisons de nous-mêmes et non dans le seul entretien physique d’un exercice sans réflexivité suffisante pour comparer le passé habituel et le nouveau geste.

Lors de sa contraction, le muscle squelettique, moteur de l’activité physique, produit de la chaleur proportionnellement à l’intensité de l’exercice réalisé. Cette chaleur se transmet à l’ensemble de l’organisme qui doit alors la dissiper pour maintenir son homéostasie thermique. Cette dissipation repose largement sur le système cardiovasculaire qui assure la convection sanguine vers le territoire cutané puis sur l’évaporation de la sueur. Malgré tout, tout exercice physique s’accompagne d’une hyperthermie plus ou moins marquée qui, si elle favorise certains processus métaboliques, peut aussi avoir des effets délétères. Ainsi lors d’un exercice réalisé en ambiance chaude, la température musculaire s’élève de manière importante, provoquant une libération de radicaux libres ou un découplage des mitochondries. Si les systèmes cytoprotecteurs sont dépassés, ces phénomènes peuvent provoquer un déséquilibre de l’homéostasie calcique de la cellule musculaire, des modifications de l’utilisation des substrats énergétiques et finalement compromettent la contraction musculaire. Une autre conséquence de l’augmentation marquée de la température musculaire est une majoration de la production physiologique de cytokines pyrogènes, particulièrement d’interleukine-6, et le risque majoré de microlésions des fibres musculaires. Ces événements sont susceptibles d’activer et de recruter des cellules immunitaires, engendrant un état inflammatoire local. Un rôle de la déplétion énergétique au sein des fibres musculaires ou des signaux inflammatoires musculaires dans la pathogénie du coup de chaleur d’exercice a été évoqué, cependant cette hypothèse reste encore à étudier et à documenter sur le plan expérimental et clinique.

L’évaluation précise de la quantité d’activité physique pratiquée de façon régulière constitue une donnée fondamentale dans l’étude de la relation entre l’activité physique et la santé. Cependant, plusieurs techniques de mesure de l’activité physique ne donnent que des résultats valables pour une seule journée comme, par exemple, la dépense d’énergie réalisée d’après une auto-évaluation par questionnaire, le nombre de pas fait d’après un podomètre, l’intensité d’activité physique mesurée au moyen d’un accéléromètre comptant le temps à faire des exercices d’intensité modérée à vigoureuse. On peut maintenant utiliser les techniques de monitorage qui informent davantage sur les comportements actifs et sédentaires pour approfondir l’étude de la relation entre la santé et la fréquence, l’intensité et la durée des mouvements accomplis. Cet article présente comment un monitorage objectif, avec une attention particulière portée à l’accélérométrie, peut dresser un bilan d’activité / d’inactivité. Au moyen de données objectives prélevées dans la littérature, on présente un bilan kinésique détaillé et des exemples d’étude de cas incorporant des données et leur interprétation. La quantité d’informations recueillies dans ce profil complet offre de nouvelles avenues de surveillance et d’études scientifiques pouvant déboucher sur de nouvelles directives en matière de pratique de l’activité physique. Nous présentons les résultats de diverses façons pour démontrer les dangers d’une mauvaise interprétation des données quand on évalue une population d’après son taux de conformité aux directives contenues dans le Guide d’activité physique canadien. Nous énonçons des recommandations en matière de profil kinésique / akinésique et nous proposons quelques pistes de recherche.

Exercise at depth and during decompression is a commonly accepted factor that affects the risk of decompression sickness in divers and aviators, but data documenting these effects are limited and conflicting. The mechanisms may be complex and influenced by several factors, such as the type and nature of exercise, the temporal course of the exercise in relation to the decompression procedure, and the diving profile. This paper reviews previous studies in this field of research, and discusses current concepts in diving activities.

To estimate energy cost of a gymnastic-like exercise performed by an astronaut during spaceflight (cosmic exercise), energy expenditure was determined by measuring mechanical work done around the center of mass (COM) of the body. The cosmic exercise, which consisted of whole-body flexion and extension, was performed during a spaceflight and recorded with a video camera. By analyzing the videotape, the internal mechanical work (Wint) against inertia load of the body segments was calculated. To compare how human muscles work on Earth, a motion similar to the cosmic exercise was performed by a control subject who had a physique similar to that of the astronaut. The total mechanical power of the astronaut was determined to be about 119 W; although the control subject showed a similar total power value, half of the power was external work (Wext) against gravitational load. By assuming a mechanical efficiency of 0.25, the energy expenditure was estimated to be 476 W or 7.7 W/kg, which is equivalent to that expended during fast walking and half of that used during moderate-speed running. Our results suggest that this form of cosmic exercise is appropriate for astronauts in space and can be performed safely, as there are no COM shifts while floating in a spacecraft and no vibratory disturbance.

Weight loss and increased physical activity may promote beneficial modulation of the metabolome, but limited evidence exists about how very low-level weight loss affects the metabolome in previously non-obese active individuals. Following a weight loss period (21.1 ± 3.1 weeks) leading to substantial fat mass loss of 52% (−7.9 ± 1.5 kg) and low body fat (12.7 ± 4.1%), the liquid chromatography-mass spectrometry-based metabolic signature of 24 previously young, healthy, and normal weight female physique athletes was investigated. We observed uniform increases (FDR < 0.05) in bile acids, very-long-chain free fatty acids (FFA), and oxylipins, together with reductions in unsaturated FFAs after weight loss. These widespread changes, especially in the bile acid profile, were most strongly explained (FDR < 0.05) by changes in android (visceral) fat mass. The reported changes did not persist, as all of them were reversed after the subsequent voluntary weight regain period (18.4 ± 2.9 weeks) and were unchanged in non-dieting controls (n = 16). Overall, we suggest that the reported changes in FFA, bile acid, and oxylipin profiles reflect metabolic adaptation to very low levels of fat mass after prolonged periods of intense exercise and low-energy availability. However, the effects of the aforementioned metabolome subclass alteration on metabolic homeostasis remain controversial, and more studies are warranted to unravel the complex physiology and potentially associated health implications. In the end, our study reinforced the view that transient weight loss seems to have little to no long-lasting molecular and physiological effects.

The use of cold-water immersion (CWI) for postexercise recovery has become increasingly prevalent in recent years, but there is a dearth of strong scientific evidence to support the optimization of protocols for performance benefits. While the increase in practice and popularity of CWI has led to multiple studies and reviews in the area of water immersion, the research has predominantly focused on performance outcomes associated with postexercise CWI. Studies to date have generally shown positive results with enhanced recovery of performance. However, there are a small number of studies that have shown CWI to have either no effect or a detrimental effect on the recovery of performance. The rationale for such contradictory responses has received little attention but may be related to nuances associated with individuals that may need to be accounted for in optimizing prescription of protocols. To recommend optimal protocols to enhance athletic recovery, research must provide a greater understanding of the physiology underpinning performance change and the factors that may contribute to the varied responses currently observed. This review focuses specifically on why some of the current literature may show variability and disparity in the effectiveness of CWI for recovery of athletic performance by examining the body temperature and cardiovascular responses underpinning CWI and how they are related to performance benefits. This review also examines how individual characteristics (such as physique traits), differences in water-immersion protocol (depth, duration, temperature), and exercise type (endurance vs maximal) interact with these mechanisms.

Physique athletes lose substantial weight preparing for competitions, potentially altering systemic metabolism. We investigated sex differences in body composition, resting energy expenditure (REE), and appetite-regulating and thyroid hormone changes during a competition preparation among drug-free physique athletes. The participants were female (10 competing (COMP) and 10 non-dieting controls (CTRL)) and male (13 COMP) and 10 CTRL)) physique athletes. COMP were tested before they started their diet 23 weeks before competing (PRE), during their diet one week before competing (MID), and 23 weeks after competing (POST) whereas CTRL were tested at similar intervals but did not diet. Measurements included body composition by DXA, muscle size, and subcutaneous fat thickness (SFA) by ultrasound, REE by indirect calorimetry, circulating ghrelin, leptin T3, and T4 hormone analysis. Fat mass (FM) and SFA decreased in both sexes (p<0.001), while males (p<0.001) lost more lean mass (LM) than females (p<0.05). Weight loss, decreased energy intake, and increased aerobic exercise (p<0.05) led to decreased LM and FM-adjusted REE (p<0.05), reflecting metabolic adaptation. Absolute leptin levels decreased in both sexes (p<0.001) but more among females (p<0.001) due to higher baseline leptin levels. These changes occurred with similar decreases in T3 (p<0.001) and resting heart rate (p<0.01) in both sexes. CTRL, who were former or upcoming physique athletes, showed no systematic changes in any measured variables. In conclusion, while dieting, female and male physique athletes experience REE and hormonal changes leading to adaptive thermogenesis. However, responses seemed temporary as they returned toward baseline after the recovery phase. ClinicalTrials.gov (NCT04392752).

Deloading refers to a purposeful reduction in training demand with the intention of enhancing preparedness for successive training cycles. Whilst deloading is a common training practice in strength and physique sports, little is known about how the necessary reduction in training demand should be accomplished. Therefore, the purpose of this research was to determine current deloading practices in competitive strength and physique sports. Eighteen strength and physique coaches from a range of sports (weightlifting, powerlifting, and bodybuilding) participated in semi-structured interviews to discuss their experiences of deloading. The mean duration of coaching experience at ≥ national standard was 10.9 (SD = 3.9) years. Qualitative content analysis identified Three categories: definitions, rationale, and application. Participants conceptualised deloading as a periodic, intentional cycle of reduced training demand designed to facilitate fatigue management, improve recovery, and assist in overall training progression and readiness. There was no single method of deloading; instead, a reduction in training volume (achieved through a reduction in repetitions per set and number of sets per training session) and intensity of effort (increased proximity to failure and/or reduction in relative load) were the most adapted training variables, along with alterations in exercise selection and configuration. Deloading was typically prescribed for a duration of 5 to 7 days and programmed every 4 to 6 weeks, although periodicity was highly variable. Additional findings highlight the underrepresentation of deloading in the published literature, including a lack of a clear operational definition.

Professional sport has always tried to entertain an audience to make money. Since the advent of the electronic mass media, the focus of the entertainment has shifted from the live audience to the remote. This has forced changes to the rules and structure of the more popular sports to increase their compatibility with the media. Although the driving force behind the alterations is ultimately economic profit, the nature of the changes is determined by the technological needs of the media. Many fans and devotees of particular sports see these changes as breaks with tradition which will have a detrimental effect on the future of their game. However, it could also be argued that "the technology is the message" (Potts 1) because sport has a long history of being changed by new technologies. To gain a true understanding of why the focus of professional sport has shifted to the remote audience all you have to do is attend a match on a rainy day. Early this year I went to watch Essendon play the Sydney Swans at the Sydney Cricket Ground. The game was close until the last five minutes and was an extremely exciting spectacle, which would have had me on the edge of my seat if it weren't pouring. I didn't have an umbrella and I was trying to make sure no water got down between my jacket and the bottom of my seat. I was faced with an interesting emotional situation of enjoying a highly skilled game and wanting the whole pointless exercise to finish so I could get dry. I wished I'd stayed home and caught the game on TV. Being wet and suddenly not knowing whether it was worth the effort annoyed me. The thought of TV made my mood worse because it was then that I noticed something for the first time. In Australian Rules, every time a goal is kicked the ball is returned to the centre of the field and bounced again to restart the game. I have memories of playing in many games where a goal was kicked and the ball raced back to the centre by an over-zealous umpire who then bounced the ball, smugly re-beginning the game before any of the actual players made it back. This was not happening at the SCG. When the ball returned to the centre the umpire waited. Once he saw a light flashed from the Channel 7 box, he bounced the ball. I knew immediately what was going on from the number of times I'd watched a game on TV and it had restarted before the ad finished. The ad light was holding up the excitement of the game and prolonging my stay in the rain. The umpire had to wait for the light to flash so the drama for the TV audience was heightened. Sport is perfectly suited to the medium of TV because "the intrinsic properties of TV will favour expression, spectacle and emotion over reason and argument" (Potts 8). Professional sport is almost entirely spectacle. The skills, the costumes and the physiques of the players all appeal to the public. The skills, the costumes, the physiques of the players all appeal to the public. The expressions on the faces of the players in close-up provoke emotion in the audience. The score has a narrative movement that creates a dramatic tension for the audience. Watching a delayed telecast, people go out of their way to not know the score in advance so that the tension and entertainment will be higher. The relationship between sport, television and, to a lesser extent, other forms of media, "is commonly described as the happiest of marriages" (Rowe 32). The media offers exposure (which generates sponsorship) as well as rights fees. Sport offers the media an almost perfect composition. Viewers are drawn to watch because "it presents a spectacle of content, drama, excitement and eventual resolution" (Wilson 37). The rate at which goals are kicked in Australian Rules allows the TV broadcaster regular opportunities to get on with its primary work: advertising. Before the flashing light was introduced, an advertisement would often finish after the game had restarted. The TV audience would be bought back to attention by the return of the program only to find the narrative already in progress. With the light this is no longer the case. A goal is scored, the narrative moves, and an ad allows the viewer freedom to move around or change the channel (a vital requirement of the ease necessary in the medium). The viewer returns to see the tension mount again. But what does this gain for the TV broadcaster? It is unlikely that this single change would determine a significant shift in audience size. A viewer may be momentarily put off by coming back to an already moving game but not to the point where they change channels. It doesn't affect the advertiser because their ad is played in full whatever happens. The light doesn't actually do anything to boost the broadcaster's income or ratings. It does, however, signify a change in the public consumption of professional sport. The focus of sport as entertainment has shifted from the live audience to the remote audience. The flashing light is not the first example. It simply stood out to me because of my background and the situation I was in. Most US sports have undergone tremendous change, affecting everything from the length of the game to the basic structure of the rules. Changes have occurred in these sports to suit the remote audience, via the media. This audience would rather stay at home and view a more detailed coverage in the comfort of their own home where the benefits far outweigh the losses. They have instant replays, commentary, statistics, no foul weather or uncomfortable seats and, most importantly, if the game turns out to be boring, they can watch something else. It is "a more satisfying and pleasant way of experiencing sport" (Rowe 147) and can attract new fans. Professional sport is trying to appeal to a larger audience as a whole, trying to get its share of the ratings. Audience shares have become a medium of exchange: the larger the audience the greater the revenue. This audience needs to be constantly entertained to stop it from pressing another button on the remote. But this is not the first example of technology changing the nature of sport. Every sport has been integrally linked with technology from its very beginning. As technologically induced change occurs in society it is reflected by changes in the nature of sport. Cricket is bound by the technology involved in the manufacture of the bat and the ball. As rubber developed and wood machining advanced, the bat advanced and batting became easier; as leather working advanced, the ball advanced and the bounce off the pitch became truer; as mechanical engines advanced, the lawn mower advanced and the ground became smoother and easier to play on. All these technological advances make changes to the way the game is played. The scientific study of physiology advanced the technology of the shoe and thereby athletics. The medically derived technology of the performance-enhancing drug changes almost all professional sports. The list goes on. Advances that affect society are reflected by professional sport. This encompasses more than just advances in materials and engineering processes. It includes the way culture follows economic systems and divides itself up into markets and work forces. Hence, the development of the professional sportsperson. Sport must capture its market in order to survive and must be compatible with changes in culture. Information technology is becoming a force in most areas of our lives and is changing the way our culture operates. Sport will change along with this and will be modified by the introduction of digital technology and the Internet. Technology creates an excess of information which changes the consumption of sport which introduces an ad light at the SCG which makes (me) the viewer want to go home and watch the TV. The technology is the message. References Potts, J. "The Technology is the Message." Thinking Media. Ed. M. Wark. Sydney: Pluto Press, forthcoming. Rowe, D. Sport, Culture and the Media: The Unruly Trinity. Buckingham: Open UP, 1999. Wilson, B. "Pumping Up the Footy: The Commercial Expansion of Professional Football in Australia." Sport and Leisure: Trends in Australian Popular Culture. Ed. D. Rowe and G. Lawrence. Sydney: Harcourt Brace Jovanovich, 1990. Citation reference for this article MLA style: Greg Levine. "Technology and Sport." M/C: A Journal of Media and Culture 3.5 (2000). [your date of access] <http://www.api-network.com/mc/0010/sport.php>. Chicago style: Greg Levine, "Technology and Sport," M/C: A Journal of Media and Culture 3, no. 5 (2000), <http://www.api-network.com/mc/0010/sport.php> ([your date of access]). APA style: Greg Levine. (2000) Technology and Sport. M/C: A Journal of Media and Culture 3(5). <http://www.api-network.com/mc/0010/sport.php> ([your date of access]).