L'objectif de cette thèse était d'une part la caractérisation des muscles respiratoires lors d'un effort incrémental jusqu'à l'épuisement et d'autre part, l'étude des effets de l'entraînement et de désentraînement spécifique des muscles inspiratoires. La première étude a confirmé le développement de la fatigue musculaire respiratoire lors d'un exercice incrémental maximal. À travers l'enregistrement de l'oxygénation au niveau du 7ème espace intercostal, la deuxième étude a montré la réduction de la désoxygénation des intercostaux et de la fatigue des muscles inspiratoires avec un exercice inspiratoire antérieur. Ensuite, nous avons montré que 5 semaines d'entraînement spécifique des muscles inspiratoires (IMT) que ce soit à haute ou à basse intensité réduit la fatigue musculaire respiratoire induite par l'exercice incrémental maximal. Cette réduction corrobore la diminution parallèle observée dans l'utilisation de l'O2 au niveau des muscles intercostaux et donc de leurs demandes métaboliques en lien avec la diminution de leur fatigabilité (Études 3 et 4). Ceci pourrait refléter une augmentation de l'apport d'oxygène au niveau des muscles locomoteurs. Ces améliorations étaient plus importantes avec l'IMT à haute résistance. Néanmoins, ces phénomènes adaptatifs gagnés à l'IMT étaient perdus après 10 semaines de désentraînement (Étude 5). Toutefois, la réduction de la fréquence d'IMT à deux séances par semaine tout en préservant la même charge résistive était suffisante pour maintenir les adaptations déjà obtenues. Les travaux de cette thèse ont donc mis en évidence l'implication des muscles respiratoires dans la limitation de l'effort incrémental jusqu'à l'épuisement et ont contribué à mieux comprendre les mécanismes explicatifs de l'amélioration de la performance après l'IMT et en particulier la fatigue et l'oxygénation musculaire respiratoire / The aim of thesis was on one hand to characterize the respiratory muscles during an incremental effort until exhaustion and on the other hand, to study the effects of specific inspiratory muscle training and detraining. We first confirmed the development of respiratory muscle fatigue during a maximal incremental exercise. Through recording of oxygenation at the 7th intercostal space, the second study showed reduced intercostal muscle deoxygenation and inspiratory muscle fatigue with a prior inspiratory exercise. Then, we showed that 5 weeks of specific inspiratory muscle training (IMT), whether at high or low intensity, reduces respiratory muscle fatigue induced by maximal incremental exercise. This reduction corroborates the parallel decrease observed in the intercostal muscle oxygen utilization and therefore in their metabolic demands in relation to their fatigability decrease (Study 3 and 4). This may reflect an increase in the oxygen supply of the locomotor muscles. These improvements were greater with high-resistance IMT. However, the IMT induced adaptations were lost after 10 weeks of detraining (Study 5). Nevertheless, reducing training frequency by up to two sessions per week while preserving the same training load was sufficient to maintain the already achieved adaptations. These results highlighted the respiratory muscle implication in the limitation of incremental effort until exhaustion and have contributed to a better understanding of the mechanisms underlying the improvement of performance after IMT particularly respiratory muscle oxygenation and fatigue

Objectives: To evaluate the effect of leg muscle fatigue on balance and to determine the contributions of the somatosensory, visual, and vestibular systems to balance of apparently healthy males and females. Design: Forty-two subjects were randomly assigned to either the experimental or control groups and then subdivided based on gender resulting in four groups (10 men/women in the experimental groups and 11 men/women in the control groups). Each subject was pre-tested on the Sensory Organization Test assessment of balance. Subjects in the experimental group then underwent a Wingate Anaerobic Test to induce leg fatigue. Following the Wingate Test subjects were post-tested on the Sensory Organization Test. Subjects in the control group rested quietly for a period of seven minutes prior to post-testing. Subjects: Forty-two volunteers without recent or chronic history of lower extremity injury, neurological deficits, or balance problems participated. Main outcome measures: Ratios for the use of the somatosensory, visual, and vestibular systems and the Composite Score were calculated. A [2(Group) x 2(Gender) x 2(Test)] mixed design ANOVA was used to analyze each of the dependent variables. Results: Analysis of Composite Score demonstrated a significant Group x Test interaction (p<0.010). The breakdown of the interaction showed no significant Test effect (p-value 0.341) for the experimental group. However, there was a significant Test effect (p-value<0.010) for the control group. There were no significant effects of fatigue on somatosensory system ratio. The analysis of the visual system ratio revealed a significant main effect (p-value 0.022) for Group. Analysis of vestibular system ratio revealed a significant main effect for Test (p<0.010). Conclusions: As demonstrated by the results of the present experiment, leg muscular fatigue is associated with significantly decreased balance. In addition, fatigue does appear to have an effect on the utilization of visual and vestibular systems. / Graduation date: 2003

Calcium channel blockers (CCB) was studied extensively in cardiology for their tissue protective effect following myocardial infarction; we hypothesized that administration of a CCB would interfere with the processes that result in exercise-induced muscle damage (EIMD) and delayed onset muscle soreness. To investigate the effects of a CCB on a development and recovery from EIMD, we used a double blind, placebo controlled protocol to administer CARDIZEM CD, 240 mg/day, for 6 days to 30 college age males and females. To induce EIMD, subjects performed 4 sets of 10 repetitions of squat, leg press, leg extension, and leg curl. We observed no treatment related difference in CPK or DOMS levels. Overall, peak quadriceps force (PQF) were not different between the Placebo and Diltiazem groups, but PQF was significantly greater in the Diltiazem groups immediately after the weight lifting bout. Average quadriceps force (AQF) values decreased in both groups following the exercise bout; however, no difference existed between the groups (p>.05). The Diltiazem group PQF and AQF values returned to the pre-exercise levels 24 hours earlier than did the Placebo group. Neutrophils decreased by 21% in the Diltiazem group compare with a 1.4% increase in the Placebo group, due to large variability in the neutrophil count at the baseline, this difference was not significant. Lymphocytes were not affected by CCB treatment. Administration of diltiazem did not interfere with the development of EIMD as measured by CPK release and the DOMS scores. Diltiazem appeared to affect quadriceps force generation immediately following the weight lifting bout and to speed the recovery of muscle force to pre-exercise level in our sample of college age adults. Heart rate was significantly lower in the Diltiazem group after the administration. There was no difference in either systolic or diastolic blood pressure after the administration between the Diltiazem and Placebo groups. The incidence of side effects was very low and similar in both groups. The administration of this dose and preparation of diltiazem does not change heart rate or blood pressure in a clinically significant fashion, and was well tolerated in our sample of college age adults. / Graduation date: 1997

The purpose of this study was to compare the effects of two different velocities of eccentric work on delayed onset muscle soreness and associated factors in untrained college-aged males. Eight untrained males 21.6 (+1.7) yrs. were recruited for the study. Three subjects did not crossover design and assigned to either a 60 deg/sec or 150 deg/sec work velocity. One hundred maximal eccentric repetitions were completed separately for both legs. Exercise treatment on both legs was carried out on the Kinetic Communicator Device. Repetitions were divided into twoexercise trials. Following the exercise treatment, 10 sets of 10 repetitions with a 5 second pause between each repetition. A five week rest interval separated the range of motion (ROM) values (24, 48, 72, 122, 144 hrs.), serum creatine kinase (Ck), (pre, 24, 72, 144 hrs.), and and the results of 2 subjective soreness scales were recorded. The results of the study demonstrated no significant difference in the velocity * time interaction for Ck, ROM, and soreness perception values; however, significant findings were demonstrated for the main effect across days within each data collection except for Ck following the 150 deg/sec trial. No significant difference could be found between each leg or between both trials following each exercise treatment. The Ck'response at the faster velocity seemed to indicate that the 150 deg/sec work trial may have produced a greater amount of muscle trauma compared to the 60 deg/sec trial without significantly effecting the soreness response.

Thesis (Ph. D.)--University of Missouri--Columbia, 2000. / "December 2000." Typescript. Vita. Includes bibliographical references (leaves 190-220). Also available on the Internet.

Thèse de doctorat : Sciences de la vie et de la santé. Biologie cellulaire et moléculaire : Paris 12 : 2004. / Titre provenant de l'écran-titre. Bibliogr. f. 102-114.

Thèse de doctorat : Sciences de la vie et de la santé : Paris 12 : 2003. / Titre provenant de l'écran-titre. Bibliogr. f. 197-216.

Reproduction de : Thèse de doctorat : Sciences agronomiques : Toulouse, INPT : 2005. / Titre provenant de l'écran-titre. Bibliogr. 325 réf.

Reproduction de : Thèse de doctorat : Génie mécanique et productique : Le Mans : 2008. / Titre provenant de l'écran-titre. Bibliogr. p. 112-119.

Thèse d'exercice : Médecine. Médecine générale : Université de Nantes : 2007. / Bibliogr.