33 research outputs found
Facteurs de variation de l'aptitude physique anaérobie (approche bioénergétique et électromyographique)
No full textLa présente thèse s'intéresse à l'évaluation des aptitudes physiques anaérobies par le moyen d'un test de terrain (la détente verticale) et, à la détermination des aspects bioénergétiques et neuromusculaires des exercices intenses répétés et brefs à charge croissante par le moyen d'un test de laboratoire (l'épreuve force-vitesse). Au total 15 sujets masculins sains et sportifs ont participé à l'épreuve force-vitesse. Ce test devrait servir, d'une part à comparer les aspects bioénergétiques et neuromusculaires des sujets Noirs et Blancs et, d'autre part à déterminer les effets d'une pré élévation par un exercice préalable intense de la lactatémie sur la puissance mécanique externe lors des exercices intenses répétés brefs à charge croissante. La comparaison de 9 sujets Noirs et 6 sujets Blancs appariés en aptitudes aérobies et en caractéristiques anthropométriques montrent qu'il existe des différences, mais très faibles entre les deux groupes de sujets au niveau des aspects bioénergétiques et neuromusculaires sur le plan anaérobie. Si la pré-élevation de la lactatémie chez 12 sujets par un exercice préalable intense n'a pas modifié significativement la puissance maximale anaérobie, elle a modifié de manière significative les comportements bioénergétiques et neuromusculaires lors de l'épreuve force-vitesse. L'étude transversale des aptitudes physiques anaérobie a connu la participation de 138 sujets divisés en 14 groupes en fonction de leurs sexes, âges (13,15, 17, 19 ans), ethnies (sujets Noirs et Bancs) et spécialités sportives (sprinters, demi-fondeurs et fondeurs). La détente verticale a consisté à réaliser un squat jump, un countermovement jump et un rebound jump sur l'ergojump. Les hauteurs de saut et les capacités des puissances anaérobies recueillies via le micro-ordinateur (psion) relié à l'ergo-jump ont permis de comparer les différents groupes de sujets. Les résultats de l'étude montrent que les plus âgés sautent plus haut et ont une capacité de la puissance anaérobie significativement plus importante que celle des plus petits. Les entraînés (surtout les sprinters) sont significativement plus performants que les non entraînés d'âge et de sexe identique. Cependant entre les filles et les garçons de même âge les garçons ont les performances supérieures mais sans différence significative. De même chez les sujets Noirs et Blancs, les différences sont très faibles et ne sont pas statiquement significatives.The present report interested the determination of the bioenergetics and electromyographics during repeated brief and intense exercises with increasing load friction using a laboratory test (force velocity test) and, the assement of the anaerobic fitness using vertical jump test. Fifteen healthy males subjects participated in the force-velocity test. This test permitted, on the one hand to compare the bioenergetics and neuromuscular aspects of the Black and White subjects and, on the other hand to determine the effects of a pre-elevation of blood lactate concentration by a previous intense exercise on the external mechanical power during the force-velocity test. The comparison of 9 Black subjects and 6 White subjects matched in aerobic aptitude and in anthropometrics characteristics showed that some differences existed, but very weak between the two groups of subjects in bioenergetics and neuromuscular aspects during the force-velocity test. If the pre-elevation of the blood lactate concentrations in 12 subjects by a previous intense exercise didn't modify the anaerobic maximal power, it modified the bioenergetics and neuromuscular aspects during the force-velocity test. A total of 138 subjects participated in the transverse survey of the anaerobic physical aptitude. They were separated in 14 groups according to their sexes, ages (13, 15, 17, 19 years), ethnic groups (Black subjects, and white subjects), and sports specialties (sprinters and long distance). The vertical jump consisted in achieving a squat jump, a countermovement jump and a rebound jump on the ergojump. The heights of jump and the anaerobic power were collected via a microcomputer (psion) connected on the ergo-jump. These variables permitted to compare different groups of subjects. The results showed significant increase of anaerobic power with the increase of âge. However between girls and boys with similar âge, boys demonstrated higher performance than girls but without significant difference. With identical âge and sex trained subjects are significantly more performing than untrained subjects. The differences between Black and White subjects are very weak and not statistically significant.AMIENS-BU Lettres (800212104) / SudocSudocFranceF
Relationship between Power Output, Lactate, Skin Temperature, and Muscle Activity During Brief Repeated Exercises With Increasing Intensity
No full textInspiratory muscle performance in endurance-trained elderly males during incremental exercise
No full textInternational audienceThe aim of this study was to compare the inspiratory muscle performance during an incremental exercise of twelve fit old endurance-trained athletes (OT) with that of fit young athletes (YT) and healthy age-matched controls (OC). The tension-time index (T-T0.1) was determined according to the equation T-T0.1 = P-0.1/P-lmax x t(i)/t(tot) where P-0.1 is the mouth occlusion pressure, P-lmax the maximal inspiratory pressure and tiittot the duty cycle. For a given VCO2, OT group displayed P-0.1, P-0.1/P-lmax ratio, T-T0.1 and effective impedance of the respiratory muscle values which were lower than OC group and higher than YT group. At maximal exercise, P-0.1/P-lmax ratio and T-T0.1 was still lower in the OT group than OC group and higher than YT group. This study showed lower inspiratory muscle performance attested by a higher (T-T0.1) during exercise in the OT group than YT group, but appeared to be less marked in elderly men having performed lifelong endurance training compared with sedentary elderly subjects. (C) 2016 Elsevier B.V. All rights reserved
Electromyographic Pattern during Gait Initiation Differentiates Yoga Practitioners among Physically Active Older Subjects
No full textInternational audienceDuring gait initiation, postural adjustments are needed to deal with balance and movement. With aging, gait initiation changes and reflects functional degradation of frailty individuals. However, physical activities have demonstrated beneficial effects of daily motor tasks. The aim of our study was to compare center of pressure (COP) displacement and ankle muscle co-activation during gait initiation in two physically active groups: a group of walkers (n = 12; mean age +/- SD 72.6 +/- 3.2 years) and a yoga group (n = 11; 71.5 +/- 3.8 years). COP trajectory and electromyography of leg muscles were recorded simultaneously during five successive trials of gait initiation. Our main finding was that yoga practitioners had slower COP displacements (p < 0.01) and lower leg muscles % of coactivation (p < 0.01) in comparison with walkers. These parameters which characterized gait initiation control were correlated (r = 0.76; p < 0.01). Our results emphasize that lengthy ankle muscle co-activation and COP path in gait initiation differentiate yoga practitioners among physically active subjects
Electromyographic Pattern during Gait Initiation Differentiates Yoga Practitioners among Physically Active Older Subjects
No full textDuring gait initiation, postural adjustments are needed to deal with balance and movement. With aging, gait initiation changes and reflects functional degradation of frailty individuals. However, physical activities have demonstrated beneficial effects of daily motor tasks. The aim of our study was to compare center of pressure (COP) displacement and ankle muscle co-activation during gait initiation in two physically active groups: a group of walkers (n = 12; mean age ± SD 72.6 ± 3.2 years) and a yoga group (n = 11; 71.5 ± 3.8 years). COP trajectory and electromyography of leg muscles were recorded simultaneously during five successive trials of gait initiation. Our main finding was that yoga practitioners had slower COP displacements (p < 0.01) and lower leg muscles % of coactivation (p < 0.01) in comparison with walkers. These parameters which characterized gait initiation control were correlated (r = 0.76; p < 0.01). Our results emphasize that lengthy ankle muscle co-activation and COP path in gait initiation differentiate yoga practitioners among physically active subjects
Cardiorespiratory fitness and functional capacity assessed by the 20-meter shuttle walking test in patients with coronary artery disease 11No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit on the authors or on any organization with which the authors are associated.
No full textEffect of Recovery Mode on Exercise Time to Exhaustion, Cardiorespiratory Responses, and Blood Lactate After Prior, Intermittent Supramaximal Exercise
No full textRelationship between Electromyogram Spectrum Parameters and the Tension-Time Index during Incremental Exercise in Trained Subjects
No full textInternational audienceThe inspiratory muscle tension-time index TT0.1 (given by P0.1/PI-max x TI/TTOT) could be used to reliably assess inspiratory muscle activity during exercise. So far, the correlation between the TT0.1 and diaphragmatic activity has not been measured and the TT0.1 has not been compared with other measurements of the inspiratory muscle load such as the transdiaphragmatic pressure index or TTdi. In this study we hypothesize that the TT0.1 measuring the mouth is a noninvasive reflection of the electromyographic activity of the diaphragm. We simultaneously measured TT0.1 and surface EMG (SEMG) of 8 trained subjects at rest and during incremental exercise. The curvature of TT0.1 and the root mean square (RMS) follow the same trend during the incremental exercise with a significant correlation between TT0.1 and surface EMG parameters (RMS; r = 0.81 p < 0.001 and MPF; r = 0.80 p < 0.001 respectively). We conclude that TT0.1 measured as s an adequate noninvasive method reflects the diaphragmatic activity during incremental exercise in healthy subjects. \textcopyright Journal of Sports Science and Medicine (2018)
Assessment of exercise capacity and respiratory muscle oxygenation in healthy children and children with congenital heart diseases
No full textMuscular and cardiorespiratory dysfunction contributes to exercise intolerance. Therefore, the aim of the present study was to characterize the cardiopulmonary response andrespiratory muscle oxygenation of children with congenital heart diseases (CHD) when compared with those of healthy children. Twelve children with CHD in New York Heart Association (NYHA) class II or III, and 14 healthy children participated in the study. All subjects performed conventional spirographic measurements and a cardiopulmonary exercise test on a cycle ergometer. Oxygen uptake (VO2), carbon dioxide production (VCO2), minute ventilation (VE), heart rate (HR), and power output were measured. Oxygenation of respiratory muscles was assessed by near-infrared spectroscopy (NIRS) during exercise and recovery. Pulmonary function was normal and no significant difference was found between groups. At rest, CHD patients had cardiorespiratory variables comparable with those of the healthy group. At submaximal intensity (ventilatory threshold) and at peak exercise, power output, HR, VO2, VCO2, and VE were significantly reduced (p < 0.01) in CHD patients. Respiratory muscles deoxygenated during exercise in both groups. However, deoxygenation was more pronounced in the CHD group than in the healthy children from an intensity of 40% up to exhaustion. Likewise, children with CHD showed a slower recovery of oxygenation than healthy children (113.4 ± 17.5 vs. 74.6 ± 13.0 s; p < 0.001). Compared with healthy children, these results demonstrated that children with CHD have reduced performance and present a defected exercise capacity. Children with CHD showed a more pronounced decrease of respiratory muscle oxygenation and slower recovery of oxygen kinetics.</p
Effects of randomization versus pre-orientation of subjects for the prediction of maximum oxygen uptake using the twelve minutes run test
No full textAim: To compare the results from twelve minutes run test (12-MRT) when subjects run singly with those obtained when subjects run in randomized groups and in pre oriented groups. Methods: 33 subjects performed the 12-MRT in four variants: Achieving alone the 12-MRT on a 400 m track (Alone); Achieving in randomised groups of three the 12-MRT on a 400 m track (Group); Achieving in preoriented groups of three the 12-MRT on a 400 m track (PO-Group); Completing alone the 12-MRT on a 200 m tract (Half-Track). At the end of each test, the rate of perceived exertion was determined. Results: No significant difference (p>0.05) was found in predicted VO2max between tests. RPE was significantly higher during PO-Group compared to Alone. Underperforming athletes elicited an underestimation of predicted VO2max in Alone more important to POGroup (12.1%) compared to Group (8%). No change of predicted VO2max was observed in the middle athletes between Alone, Group and PO-Group. For the fastest athletes, predicted VO2max was significantly lower (p<0.05) for PO-Group compared to Alone where as for the Group, predicted VO2max was higher (p<0.05) compared to Alone. Conclusion: These results suggest that prediction of VO2max using the 12-MRT is influenced by peer relationship and the training status of athletes
