Muscle enzyme release does not predict muscle function impairment after triathlon.

BACKGROUND: We sought to determine the effects of a long distance triathlon (4 km swim, 120 km bike-ride, and 30 km run) on the four-day kinetics of the biochemical markers of muscle damage, and whether they were quantitatively linked with muscle function impairment and soreness. METHODS: Experimental design: Data were collected from 2 days before until 4 days after the completion of the race. Participants: Twelve triathletes performed the triathlon and five did not. Measures: Maximal voluntary contraction (MVC), muscle soreness (DOMS) and total serum CK, CK-MB, LDH, AST and ALT activities were assessed. RESULTS: Significant changes after triathlon completion were found for all muscle damage indirect markers over time (p < 0.0001). MVC of the knee extensor and flexor muscles decreased over time (p < 0.05). There is disparity in the time point at which peak values where reached for DOMS, MVC and enzyme leakage. There is no correlation between serum enzyme leakage, DOMS and MVC impairment which occur after triathlon. CONCLUSIONS: Long distance triathlon race caused muscle damage, but extent, as well as muscle recovery cannot be evaluated by the magnitude of changes in serum enzyme activities. Muscle enzyme release cannot be used to predict the magnitude of the muscle function impairment caused by muscle damage.     

Effets du repas précompétitif sur la perception de l'effort et sur la glycémie lors d'un exercice de pédalage

The first purpose of the present study was to investigate the effect of three different preexercise meals on perceived exertion and glycaemia during a one-hour bicycle exercise at 80% VO₂ max. The second purpose of this study was to determine the relationship between glycaemia and perceived exertion. Eight athletes (age: 24.6 ± 2.7 years, weight: 78.0 ±6.8 kg, height: 182.6 ± 9.9 cm) completed three assessment sessions, each being preceeded by one of the following meals, ingested 3 h before exercise: 400 mL of water, 400 mL of water and 75 g of glucose, and 100 mL of water and 375 g of potatoes. The subjects 'perceived exertion were measured at times 6, 15, 30, 45, 60 min and glycaemia at 0, 30, 60 min of the exercise. The results showed that perceived exertion (RPE and ETL) of each meal increased as a function of time (P <- 0.05) whereas glycaemia did not differ except for the glucose meal between 30 min and 1 h(P < 0.02). There was no significant difference in ratings of perceived exertion among any meal whereas glycaemia was different between the three conditions only at the beginning and the middle of the exercises (P < 0.04 and P < 0.02, respectively). Moreover, the vectorial angles between the variables ofperceived exertion and the glycaemia are close to 90 °. These results would suggest that perceived exertion does not seem to be affected by the three preexercise meals used in our study. Perceived exertion is not correlated to glycaemia changes during one-hour high intensity exercise. The results would, therefore, suggest that glycaemia is not a contributor signal of perceived exertion in this study. It seems that physiological factors other than glycaemia may have mediated the perceptual intensity at exhaustion. The respiratory-metabolic signals of exertion which are most pronounced at high relative exercise intensity are suggested to influence the perceptual signal of exertion.     

Evaluation échographique des effets cardiaques de la course à pied chez le marathonien et le sédentaire avant et après entraînement

Left ventricular (LV) morphology and function were studied by echocardiography at rest in 25 Marathon (M) runners and 11 sedentary young adults before and after two years of periodic endurance training.The following echocardiographic TM computerized measurements were performed: LV diameters (D) thickness (Th) mass, and the maximum rates of posterior wall thickness (PWTh) changes in systole (SdTh/dt/Th) and diastole (DdTh/dt/Th).When compared to 20 normal adults (Nls) Marathon runners exhibited significant increase in LV end-diastolic diameters, thickness and mass (156 ± 38 vs 111 ± 29 g/m², P<0.001). This myocardial hypertrophy was associated with a decrease in LV contractility (StdTh/dt/Th M 3.2±0.7 vs Nls 4.8±1.2 P<0.001) and relaxation (DdTh/dt/Th M 4.6±1.2 vs Nls 7±1.6 S⁻¹ P<0.001). The ratio of end diastolic LV D/2 by PWTh was significantly lower in M (2.66±0.58) than in Nls (3.25±0.72 P<0.01). These results suggest that in M LV hypertrophy is ‘inappropriate’ at rest but perfectly adapted to effort, because long distance runners have the unique alibity to increase their diastolic LV dimensions during exercise.On the opposite, two years of periodic training, allowing 11 sedentary men to run 20 km at 10 km/hour speed, greatly increased their physical condition assessed by stress test but produced no changes in echocardiographic parameters under basal conditions.This longitudinal prospective echocardiographic study demonstrates that long term intensive prolonged running program is required to modify ventricular muscle when studied at rest.     

Influence d'un triathlon courte distance sur la performance des muscles respiratoires

Objectives – The aim of the present study was to investigate the influence of a short distance triathlon (1.5 km swim, 40 km cycle, and 10 km run) on respiratory muscle performance.Methods and results – Nine male triathletes underwent the measurement of respiratory muscle strength (maximal expiratory and inspiratory pressures), and respiratory muscle endurance (Time limit), before the competition (Pre-T), at the end (Post-T) and 24 h later (post-T-24 h). The results showed, 1) the absence of significant difference in maximal expiratory pressure (P > 0.05), 2) a significant decrease in maximal inspiratory pressure and time limit at Post-T and Post-T-24 h (P < 0.05).Conclusion – We concluded that a short distance triathlon induced an inspiratory muscle fatigue, showed by a significant decrease in strength and endurance of these muscles.     

Évolution des erreurs techniques et de quelques variables physiologiques pendant la course d'orientation

During orienteering, the accumulation of technical errors (TE) can be an important factor of handicap at the arrival. In the same conditions of championships, ten voluntary national runners (age: 29.2 ± 3 years, height: 176.8 ± 3.5 cm, body mass: 65.0 ±6.8) participed to the study. Firstly in laboratory the subjects performed a treadmill test in order to study their physical capacity (aerobic fitness and oxygen consumption). The initial speed (12 km·h⁻¹) increased by 1 km·h⁻¹ every 4 minutes. During the last minute of each step a blood sample (50 μl) was taken on a finger for lactate analyze (Kontron). Two days later the subjects participed in an orienteering race (OR) of four loops (Bi₁, B₂, B₃, B₄) stepping in a central point; the first and third loops (B₁, B3) were technical orienteering while the second and the fourth (B₂, B₄) were rough orienteering. During the race the heart rate (HR) was recorded by means of a Sport Tester PE 4 000. The nature, the number and the moment of TE were determined with the help of the map area of each subject and time keeping. During OR the subject's physical capacity (running speed, HR, lactates, carbohydrate) was evaluated when the runners arrived at the crossing point of the loops. The results give some evidence that the anaerobic threshold quickly is reached during technical orienteering (B₁) and stay at a level hihger than 4 mmoles.l⁻¹ during the whole field test, suggesting that the energy expenditure was very high. It is difficult to compare the physical capacity and the psychological behavior of the subjects during OR yet two distinctive critical pediods have been observed for TE in OR (B₃, B₄); nevertheless our study confirms that the number of TE (which is a picture of the mental performance) is linked to the decrease of the physical capacity. Indeed the increase of HR (HRmax-HRmin) during OR stabilized in the first three loops (B₁, B₂, B₃) at 25 beats, min⁻¹, then the increase of HR was about 31 beats.min⁻¹ in B4. This increase of HR (HRmax-HRmin), is due to the muscular fatigue, the subjects must have some rest and they run slowly because the carbohydrates decrease, excepted for the best runners. Thus the consequences of an insufficient warm-up in the first quarter of the race and/or supply of energetics substrates during the whole OR has been brought to attention.     

Comparaison de l'oxydation de glucose, d'un mélange de glucose et de fructose, et de saccharose ingérés en bolus ou en doses fractionnées au cours de l'exercice

The purpose of this study was to compare the oxidation rates ofisocaloric amounts of glucose (G), of a mixture of glucose and fructose (G+F), and of sucrose (S) ingested during prolonged exercise (120 min, 58 % V0₂max). The mode of ingestion, that is in a bolus at the onset of exercise or in fractionated doses during the exercise, was also investigated. Six young male subjects ingested a placebo (P), 100 g of G, 50 g of G + 50 g of F, or 95 g of S (13 % concentration) in fractionated doses during exercise, and 100 g of G and 50 g of G + 50 g of F in a bolus at the beginning of exercise. Blood samples were taken before and during the last minute of exercise period. Ingestion of carbohydrates (CHO) does not influence the blood glucose and insulin levels, but decreases by 50% the response of plasma free fatty acid concentration. During the 120-min exercise period, the amounts of ingested carbohydrates which were oxidized were similar for G (53 ± 5 g), G+F (57 ± 6 g) and S (50 ± 7 g). Exogenous CHO oxidation contributed to increasing the total CHO utilization (from 181 to 200 g/120 min) and to reducing fat oxidation (from 86 to 72 g/120 min). Ingestion of CHO as a bolus at the beginning of exercise does not influence G oxidation (58 ± 6 g) but significantly increased the oxidation of the mixture G+F (67 ± 6), probably by favoring fructose utilization which requires a delay. From a practical viewpoint, these results show that the oxidation of S, which is the most widely available oligosaccharide, is similar to that of G or a mixture of G+F. Moreover, in order to maximize exogenous CHO oxidation during exercise, CHO should be ingested early in the exercise period, and not in fractionated doses throughout the exercise period.     

Changes of urinary 8-hydroxydeoxyguanosine levels during a two-day ultramarathon race period in Japanese non-professional runners

Using the urinary 8-hydroxydeoxyguanosine (8-OHdG) concentration, effects of participation in a two-day ultramarathon race period on oxidative DNA damage were investigated in Japanese nonprofessional runners. Before the first day (baseline), after the first day (mid-race) of 40-km running, and after the second day (post-race) of 90 km running, biomaterials were successfully sampled from 95 participants (males, 79; females, 16) who completed the full race. We analyzed urine for 8-OHdG and blood for aspartate aminotransferase (AST), creatine phosphokinase (CPK) and myoglobin, and evaluated fluctuation in the values at three sampling time points. Adjusted baseline urinary 8-OHdG levels (microg/g creatinine) (mean +/- standard deviation) showed no significant differences between males and females, at 2.85 +/- 1.17 and 3.04 +/- 1.56, respectively. In males, mid-race urinary 8-OHdG levels rose to 3.29 +/- 1.15 (p < 0.01), but then returned to 2.73 +/- 1.16 at the post-race time point (p < 0.01). In females, a similar increase to 3.32 +/- 1.47 and subsequent decline to 2.80 +/- 1.47 were noted. In contrast, AST, CPK and myoglobin were increased at both mid- and post-time points and particularly the latter, independent of the sex. Extreme prolonged exercise in a two-day ultramarathon race period causes oxidative DNA damage but antioxidant repair systems are apparently induced to protect against oxidative DNA stress with physical exercise.     

Vieillissement et désaturation oxyhémoglobinée du sportif

A extreme athlete can be defined as an athlete able to exceed the limit of one function in such a way that failure of another function appears. For example extreme athletes in endurance events are able to exceed the normal limits of cardiac output but show a hemoglobin desaturation by the end of exhaustive exercise. Usually, these athletes have had a maximal oxygen uptake (O₂ max) greater than 65 ml·min⁻¹. The aim of this study was to determine whether hemoglobin desaturation occurs in master athletes and whether aging facilitates this phenomenon. Nine master athletes aged 62–75 participated to this study. They practised leisure cycling 5000 to 14000 km per year. Hemoglobin saturation was measured non-invasively using the transcutaneous method during both incremental exercise until exhaustion and constant load exercise at 70% and 90% of O₂ max for a 15 min period. We considered that there was a desaturation if SaO₂ decreased by 4%. During maximal incremental exercise we observed desaturation in six subjects. These results were confirmed during constant load exercise at 90% of O₂ max. It is interesting to note that one of the subjects, whose desaturation was 8% during incremental exercise, showed a desaturation of 16% at the 15th minute of constant load exercise at 90% O₂ max. In our master athletes this desaturation was observed for O₂ max and pulse oxygen values respectively equal to 1/2 and 2/3 of the values of young athletes. Aging thus seems to facilitate the mechanisms of athlete's desaturation. These mechanisms are highly speculative. One can, however, suspect the role of relative hypoventilation, a ventilation-perfusion inequality, and a diffusion limitation. A decrease of red blood cell transit time in the pulmonary capillary may also play a role, as there is a decrease in pulmonary capillary volume in master athletes over 60 years and that maximal cardiac output does not seem to decrease with age.     

Relation entre le lancer de balle et la force isocinétique des rotateurs d'épaule chez le handballeur de haut niveau

Objectives. – The aim of this study was to calculate correlations between isokinetic torque of the internal and external dominant shoulder rotators and ball velocity in high-level handball players.Synthesis of facts. – Internal and external shoulder rotators were examined in twenty-one national level handball male players on the concentric mode action at 60, and 120°/second. External rotators were examined on the eccentric action at 60 and 120°/second. Concentric ratio ERcon/IRcon and mixed ratio ERecc/IRcon were calculated. Ball velocity was measured in three types of throw: throw in seated position, standing throw and throw with three meter running jump. After statistical analysis using the Spearman correlation coefficient, no correlation was found between strength of internal and external shoulder rotators and ball velocity. The relationship between ball velocity of the throw in seating position and concentric and mixed ratios at 60 and 120°/second was significant (P < 0.01).Conclusion. – Peak torque of internal and external rotators of the dominant shoulder was not a good indicator of throwing velocity.     

Augmentation de la fréquence d’apparition de l’hypoxémie induite par l’exercice chez des rameurs de haut-niveau

Objectifs. – Évaluer la fréquence d’apparition de l’hypoxémie induite par l’exercice (HIE) chez un groupe de rameurs de haut-niveau.Méthodes. – Sept rameurs de haut-niveau ont participé à l’étude (19,14 ± 1,3 ans). Les sujets ont effectué une épreuve d’effort à charge croissante sur un rameur ergométrique lors de laquelle les échanges gazeux et la saturation de l’hémoglobine en oxygène (SpO₂) ont été mesurés.Résultats. – Les sujets avaient une VO₂max de 61,68 ± 1,65 ml/min par kilogramme. Tous ont présenté une HIE avec des chutes de SpO₂ comprises entre 5 et 11 %. Cette chute était significative dès 70 % VO₂max. Le volume d’entraînement réduit des athlètes testés par rapport aux autres athlètes endurants semble indiquer que le phénomène est indépendant du volume d’entraînement.Conclusion. – Cette étude a permis de mettre en évidence que 100 % des rameurs de haut-niveau présentaient une HIE. La limitation ventilatoire et l’importante masse musculaire mise en jeu spécifiques à l’aviron seraient les hypothèses explicatives.Aim. – To access the frequency of exercise-induced hypoxemia (EIH) in elite oarsmen.Method. – Seven elite oarsmen participated (19.14 ± 1.3 year) in this study. Subjects performed an incremental exercise testing on a rowing ergometer. Gas exchanges and pulse oxymetric saturation in oxygen (SpO₂) were measured during exercise.Results. – Subjects exhibited a mean of VO₂max of 61.68 ± 1.65 ml min^–1 kg^–1. All rowers showed an EIH with a SpO₂ ranging between 5% and 11%. This SpO₂ fall was significant from 70% VO₂max. The reduced training volume of our athletes compared with others endurance trained athletes seems indicate that phenomenon is not dependent of training volume.Conclusion. – This study showed that 100% of elite oarsmen exhibit EIH. Mechanical limitation in ventilation and great muscle mass involved in rowing could be the explicative hypothesis.     

Medical considerations in triathlon competition: recommendations for triathlon organisers, competitors and coaches

Competitors in triathlons experience a range of environmental conditions and physiological demands in excess of that found in individual sport events of comparable duration. Consequently, there is a broad range of possible medical problems and complications that must be taken into account when preparing for such races.For most competitors, an Olympic-distance triathlon typically takes between 2-4 hours to complete. This race begins with a swimming segment of 1500 m. Given the wide variety of race venues found around the world, these swims occur in an assortment of water temperatures (from warm to cold) and conditions (from ocean surf to lake calm). Swimmers often exit the water in a state of moderate dehydration and hypothermia and then immediately start the 40 km cycling leg. Many do so in their swimming attire. A wide variety of road surfaces, technically challenging topography, variable environmental conditions and dramatically changing velocities can be encountered on the cycle course. The race concludes with a 10 km running leg. Since it is the final leg, it is often completed in higher ambient temperatures than those encountered at the start, with the athlete possibly running in a significant state of dehydration and fatigue.Other medical problems commonly encountered in triathlon include: muscle cramping, heat illness, postural hypotension, excessive exposure to ultraviolet radiation, musculoskeletal injuries and trauma, gastrointestinal problems as well as post-race bacterial infection, immunosuppression, sympathetic nervous system and psychological exhaustion, and haemolysis. The rate of occurrence of such events and the severity of their potentially negative outcomes is a function of the methods used by both the race organisers and the competitors to prevent or respond to the conditions imposed by the race.Triathletes also commonly compete in both shorter 'sprint distance' events (in the range of a 0.75 km swim, 20 km cycle and 5 km run) and longer events including both one-half and full Ironman distances (2.5 and 3.8 km swim, 80 and 180 km cycle, 20 and 42 km run, respectively), as well as ultra-distance events that exceed the Ironman distance. In the longer events, the previously mentioned medical considerations are further magnified and additional considerations such as hyponatraemia can also occur. Reducing risk associated with these concerns is accomplished by: taking into account weather and water temperature/conditions data prior to event scheduling; effective swim, cycle and run course organisation and management; environmental monitoring prior to and during the event; the implementation of a water safety plan; provision of appropriate fluid replacement throughout the course; implementation of helmet use and non-drafting regulations in the cycling leg; and competitor knowledge regarding fluid replacement, biomechanical technique, physical preparation, safe equipment and course familiarity. Despite these concerns, triathlon participation appears to relatively safe for persons of all ages, assuming that high-risk adults undertake health screening.     

Prediction of triathlon race time from laboratory testing in national triathletes

PURPOSE: Four days after competing in an Olympic-distance National Triathlon Championship (1500-m swim, 40-km cycle, 10-km run), five male and five female triathletes underwent comprehensive physiological testing in an attempt to determine which physiological variables accurately predict triathlon race time. METHODS: All triathletes underwent maximal swimming tests over 25 and 400 m, the determination of peak sustained power output (PPO) and peak oxygen uptake (VO2peak) during an incremental cycle test to exhaustion, and a maximal treadmill running test to assess peak running velocity and VO2peak. In addition, submaximal steady-state measures of oxygen uptake (VO2), blood [lactate], and heart rate (HR) were determined during the cycling and running tests. RESULTS: The five most significant (P < 0.01) predictors of triathlon performance were blood lactate measured during steady-state cycling at a workload of 4 W x kg(-1) body mass (BM) (r = 0.92), blood lactate while running at 15 km x h(-1) (r = 0.89), PPO (r = 0.86), peak treadmill running velocity (r = 0.85), and VO2peak during cycling (r = 0.85). Stepwise multiple regression analysis revealed a highly significant (r = 0.90, P < 0.001) relationship between predicted race time (from laboratory measures) and actual race time, from the following calculation: race time (s) = - 129 (peak treadmill velocity [km x h(-1)]) + 122 ([lactate] at 4 W x kg(-1) BM) + 9456. CONCLUSION: The results of this study show that race time for top triathletes competing over the Olympic distance can be accurately predicted from the results of maximal and submaximal laboratory measures.     

L'aptitude physique: étude comparée chez l'homme et la femme

Comparison of male and female performance trends in athletics and swimming over the last decade shows that women tend to improve their results less rapidly than men. Does this divergence reflect unequal physical capacities? Measuring performance implies the determination of numerous (biological, psychological, sociological) elements. For most authors, physical capacities are decisive in explaining performance levels, as expressed by energetic and biochemical factors. The latter are analysed in this study in order to compare performances in both sexes. Energy expenditure may be assessed through the study of maximum aerobic power and aerobic endurance. During tests which required a significant amount of aerobic power, female were observed to be lower than male performances. These differences may be explained by the lower maximal oxygen uptake (O₂ max) in women. Absolute O₂ max values, expressed in 1·min⁻¹ are typically 30 to 50% higher in men than in women. Using the relative expression of O₂ max, in ml of oxygen per kg of body weight, the apparent sex difference in maximal aerobic power is reduced to approximately 20%. Thus, part of the sex difference in O₂ max is related to the difference in body size and weight. One factor known to influence O₂ max is relative body fat. If O₂ max is expressed relative to fat-free weight, the sex difference in O₂ max is further reduced and, in some cases, ceases to exist. A smaller heart size and a lower hemoglobin concentration are two factors which are proposed as a possible hypothesis to explain this variation. The sex differential in O₂ max between trained men and women was less than for untrained subjects. On the other hand, during exercise involving moderate speed, women displayed better endurance properties than men. This observation indicates that females depend upon aerobic energy turnover and fat combustion to a larger extent than males. A higher lipid contribution to energy metabolism was explained in women compared to men via the lower values of respiratory exchange ratios obtained in women for oxygen uptake values below 75 to 80% of maximal oxygen uptake.The biochemical component takes into consideration the strength characteristics are produced by muscle and the conditions under which thus strength is manifested, assessed through efficiency study. Men are usually stronger than women because they have more muscle mass. However, when muscular strength is expressed relative to lean body mass or to cross-sectional area of muscle, sexual differences are reduced significantly. Signifaicant differences in gross energy expenditure are apparent between men and women but when expressed in relation to body weight, the difference in energy cost is decreased. These differences are also dependent upon activity and training level.In general, women have a significantly lower capacity to perform physical work than men. The effects of physical fitness training do not alter these differences.     

Effects of a Deca Iron Triathlon on body composition: a case study

We investigated energy balance and change of body composition in one athlete in a multistage triathlon, the World Challenge Deca Iron Triathlon 2006, where athletes had to perform one Ironman triathlon of 3.8 km swimming, 180 km cycling and 42.195 km running per day for ten consecutive days. In one well-experienced male ultra-endurance triathlete, we measured body mass, skinfold thicknesses and perimeters of extremities, in order to calculate skeletal muscle mass, fat mass and percentage of body fat. Energy intake was measured by analysis of nutrition, and energy expenditure was calculated using a portable heart rate monitor. This was performed to quantify energy deficit. In addition, bio-impedance measurements were performed to determine fluid metabolism. The athlete finished the race in 128 hours, 22 minutes and 42 seconds in 3rd position. Body mass decreased by 1 kilogram, skeletal muscle mass decreased by 0.9 kilograms and calculated fat mass decreased by 0.8 kilograms. Total body water increased by 2.8 liters. Total energy expenditure for the Deca Iron was 89,112 kilocalories and a total energy deficit of 11,480 kilocalories resulted. We presume that energy deficit was covered by consumption of adipose subcutaneous tissue as well as skeletal muscle mass; the degradation of muscle mass seems to lead to hypoproteinemic edemas.     

Influence de l'exposition au froid sur le seuil anaérobie

During a maximal effort performance test of short duration at 0°C, we have observed that the blood lactate concentration at max V˙O₂ is lower than the value obtained during the same cycling exercise at 20°C. In light of these results it is of interest to determine if the anaerobic threshold measured using various lactic acid values occurs at the same relative power output whether it is assessed in a cold or in a neutral thermic environment. Eleven male hockey players (mean age = 23.9 years) were tested during maximal cycle ergometer pedalling in a climatic chamber at 0°C and 20°C. Measurements of gas variables were made at rest and at the last minute of each work steps. Blood samples were collected at rest and thereafter during the last 15 sec of each third minute from an antecubital vein through an indwelling catheter for subsequent analysis of lactate concentration. Determination of percentage max V˙O₂ corresponding to the anaerobic threshold was assessed at a blood lactate concentration of 4 mmol.l⁻¹. Under thermal equilibrium (20°C), the onset of anaerobiosis occurred at 80% of the maximal oxygen uptake.V˙O₂ and pulmonary ventilation (V˙E) values at the onset of the anaerobic threshold were 3.5 (SD = 0.02)l.min⁻¹ and 99 (SD = 6.0)l.min⁻¹, respectively. Under cold conditions, the onset of anaerobiosis occurred at approximatively the same relative power output (82% max V˙O₂). Although max V˙O₂ is significantly higher under cold conditions than it is under a neutral environment, the max V˙O₂ value at the threshold is not significantly different than the one measured under the neutral environment (3.6 ± 0.1 l.min⁻¹). Heart rate is identical in both conditions and V˙E is not significantly different. Below the threshold workload, blood lactate concentrations are identical under both cold and thermal equilibrium conditions. For workload above the threshold, the blood lactate concentration increase under cold stress seems less (P < 0.05) in comparison to the accomplished pedalling exercise under thermal equilibrium (7.9 ± 0.29 vs 6.0 ± 0.42 mmol.l⁻¹). We can conclude that the effect of cold exposure above the anaerobic threshold is to decrease significantly the blood lactate concentration. However, cold stress does not lower the anaerobic threshold nor V˙E at which this threshold appears.     

Changes in physiological and performance variables in non-professional triathletes after taking part in an Olympic distance triathlon

Given increasing popularity of triathlon, the objective of this study was to evaluate the acute effects upon the health of triathletes. To do so, with a sample of 23 male athletes (34.4 ± 7.9 years old), an assessment was carried out both before and after an Olympic distance triathlon, of the bodily composition, the jumping ability and the BORG and VAS scales, as well as a blood analysis of the following: Lactate (mmol/L), Hematrocrit (%), Glucose (mg/dL), Total proteins (mg/dL), Triglycerides (mg/dL), Bilirubin (mg/dL), GOT (IU/L), GPT (IU/L), LDH (IU/L), CPK (IU/L). The results showed an increase (p < 0.001) in the different markers of metabolic stress and muscular damage following the triathlon, but always within a normal range considered to be healthy, with the exception of CPK (IU/L) (PRE 149.33 ± 108.16 vs POST 290.10 ± 102.48). Therefore, it would seem that competing in an Olympic-distance triathlon does not pose health risks for trained subjects.     

Aptitudes cardiorespiratoires à l'exercice et fonction musculaire périphérique chez des enfants infirmes moteurs d'origine cérébrale

Introduction. – The aim of this study is to assess the aerobic capacity and the skeletal muscle function (force and muscular endurance of quadriceps muscle) in children with cerebral palsy (CP) compared with healthy children.Synthesis of facts. – In children with CP, the aerobic capacity during exercise is lower compared with healthy children in association with an impaired maximal isometric force and endurance of the quadriceps muscle.Conclusion. – Children with CP have a lower aerobic capacity and an impaired skeletal muscle function compared with healthy children.