Évaluation de l'état de stress oxydatif chez des footballeurs et des basketteurs professionnels

Aim – Evaluation of oxidative stress status.Methods and results – Mean values in antioxidant vitamins, sulphydryl proteins and selenium were found to be in a normal range in the blood of top soccer (n=21) and basketball (n=9) players at the end of half a season of regular training and competititon. Glutathion peroxidase levels were higher than the mean superior value in fourteen players, suggesting a possible adaptation to oxidative stress induced by physical exercise.Conclusion – Despite an apparent normal antioxidant status, the presence of such an oxidative stress is confirmed in half of the players as evidenced by elevated levels in autoantibodies against oxidized lipoproteins.     

Évaluation des masses musculaires et des densités osseuses régionales chez des kayakistes de haut niveau

Aim. – To determine the body composition and bone densities in elite teenagers kayak paddlers.Materials and methods. – The population consisted of 14 boys (seven kayak paddlers and seven controls). The training frequency of kayak paddlers was 10 h/week when the control group had less than 4 h/week of physical activity. The body composition and bone density were measured by DXA.Conclusion. – The intensive kayak training seems to improve lean body mass and bone density at the specific sites involved in this activity (arms, trunk).     

Évolution de la lactatémie lors d'une séance de vitesse chez des sprinters de niveau national

Aim – We measured in this work the plasma lactate concentrations in male sprinters competing at national level after repetitions of 50 m sprint at maximal speed on the track.Results – Plasma lactate concentration increases significantly after the first repetition of sprint, from 3.9 ± 0.1 mmol.l⁻¹ before the first sprint to 14.0 ± 3.0 mmol.l⁻¹ observed after the 3th repetition.Discussion and conclusion – Our results confirmed that the activity of the lactic anaerobic metabolism reflected by plasma lactate concentration is very high during the first seconds of sprint exercises below seven seconds. Sprint coaches must take into account these data when they program sprint sessions.     

Variation de l'amplitude de l'onde T au cours de l'exercice et pendant la récupération chez des sportifs entraînés

Aims. – To study T-wave amplitude changes during exercise and recovery in trained athletes.Methods and results. – Thirty two athletes of both sexes underwent an incremental cycle test. Cardiac electric activity (ECG) was recorded every minute during exercise and the following five minutes of recovery. T-wave amplitude was manually measured on V5 ECG complex enlarged 4-fold. The statistical analysis was done using two factor's Anova. The results showed that T-wave amplitude 1) increased significantly during the three first minutes of the recovery, 2) was not linked to T-wave decrease or increase during previous exercise, and 3) was significantly lower in females than in males. Pathophysiological mechanisms of this ECG repolarisation in athletes during recovery following exercise remains unclear.     

Dopage et sport : connaissances et attitudes des pharmaciens de la ville de Yaoundé

Introduction – Fourty-one retail pharmacists (23 females and 18 males) out of 70 that Yaoundé town counts, participated to this study aimed at determining their attitudes towards and knowledge in doping. They answered a questionnaire concerning their knowledge of doping agents, how they face doping and the role of pharmacists in doping prevention.Synthesis – Results suggest that pharmacists (54%) have been confronted to doping, less than once a month for 27% of them and at least once a month for the rest. Six pharmacists (15%) have been offered to provide doping agents to sport men. 51% (mainly females) consider that the use of food supplements could induce consumption of forbidden drugs. The majority (83%) of pharmacists (mainly females) consider that doping is a public health problem. They agree (88%) that pharmacists have a part to play in doping prevention but also agree (58%; mainly females) that they are poorly or very poorly informed to that effect.Conclusion – The requests made to pharmacists suggest the consumption of doping agents by sport men in our region. It is therefore necessary to carry out an epidemiologic study on prevalence and consumption patterns.     

Dynamique de la locomotion en fauteuil roulant manuel : influences de la masse totale et de sa répartition antéropostérieure sur la résultante des forces de freinage

Purpose. – This study presents a new method for determining the resultant braking force during wheelchair displacement and investigates the respective effects of the level and the distribution of the system’s mass.Method and results. – A three-dimensional accelerometer was fixed directly under the seat of wheelchair and was used to measure the deceleration of the mass-and-wheelchair’s system. Three masses (50, 70 and 90 kg) were laid on a support in 3 positions corresponding to three distributions (10, 40 and 70%) of the system’s total mass upon the front casters. A series of 15 deceleration trials was performed for each of the 9 combinations. Statistical results showed that the system’s deceleration was mainly explained by the mass distribution upon the front casters (92%) and in the least by the system’s total mass (8%).Conclusion. – Considering the fore-and-aft movements of the subject’s centre of mass during wheelchair locomotion, the results of this study let us assume that the resultant braking force does not remain constant along the propulsion cycle. Moreover, the present method could be used to investigate the influence of wheelchair’s adjustments and floor’s characteristics on the resultant braking force.     

Fréquence cardiaque chez des adolescents âgés de 11 à 16 ans lors de séances d'éducation physique intensifiées

Introduction – Exercise physiologists notice sometimes that Physical Education (PE) sessions are lacking of intensity. This lack of intensity would not allow obtaining desired physiological responses. Thus, we measured heart rate (HR) in adolescents (boys and girls) aged 11–16 years old during intensified EP lessons.Method and results – Sessions consisted in short intermittent running (G1) and jumping exercises (G2). Heart rate was averaged over 30 min. There was no significant difference between mean HR for G1 and G2 (154±12 vs 155±12 bpm, p<0.001). Nevertheless, for both G1 and G2, mean HR was significantly higher for girls than for boys (153±12 vs 156±12 bpm, p<0.001).Conclusion – This type of intensified lessons request at a high level adolescents HR (75.4±5.4% of maximal HR) to reach health objectives.     

Étude des modifications de la balance ortho–parasympathique à l’issue de vols acrobatiques chez des pilotes de voltige aérienne

Objectives – Study was the ortho-parasympathetic balance changes assessment after an aerobatics flight (called push-pull).Conclusion – Post flight fatigue of the autonomic nervous system involved by the “push-pull” accelerations was expressed by changes of the resting ortho-parasympathetic balance.Protocol – Five pilots performed a training flight of 30 minutes with 5 series of 30 seconds of spirals down under negative acceleration (–3 Gz; –4 Gz) followed by 30 seconds of spirals down under positive acceleration (+3 Gz; +4 Gz). Between each series, pilots carried off a flat flight. A stand-test (10 minutes fall flat on the ground, 10 minutes stand up) was realised before flight, 5 minutes after landing, 1 et 2 hours after flight. Electrocardiogram was recorded during the stand-test with an analogical device). Blood pressure was recorded with an automatic monitor.Results – Spectral analysis of resting heart rate variability and blood pressure variability recorded during stand-tests revealed a continuous disturbance of the ortho-parasympathetic balance after flight probably related to the disturbance of the baroreflexe control. Indeed the compared evolutions of heart rate and blood pressure variability before versus after flight showed an increase in sympathetic tone just after flight and an increase in parasympathetic tone during 2 hours after flight.     

Effet de la castration sur le développement des muscles squelettiques

Introduction – Study the effects of the castration on skeletal muscle.Synthesis of facts – Physical and chemical muscle characteristics of 90 males, females and males rabbits castrated at three days were studied after slaughter when 14 weeks old. Longissimus dorsi muscle was analysed. LD chemical characteristics were insignificantly modified by castration. LD muscle was significantly more tender for females and castrated males than for entire males.Conclusion – The castration affects internal structure of skeletal muscle of rabbits slaughtered at 14 weeks of age.