30-15 Intermittent Fitness Test et répétition de sprints

Introduction

The maximal running velocity (V_IFT) reached at the end of the 30-15 Intermittent Fitness Tests (30-15_IFT) is very well related to most physiologic determinants of team-sport performance: explosive power of lower limbs, speed, maximal aerobic power and the ability to recover between exercise bouts. Nevertheless, its relationship with repeated sprint ability (RSA) was unknown.

Synthesis of the facts

Present results in 84 team-sport athletes show that V_IFT is very well related to mean sprint time during a RSA test (p > 0.001).

Conclusion

We conclude that V_IFT is highly representative of most physiologic determinants of performance in team-sports, and could thus been used to monitor athletic performance of team-sport players.     

Relation entre la puissance et la raideur musculotendineuse chez les sportifs de haut niveau

Goal

The aim of this study was to test the relation between the reactive power and the stiffness of the legs in high trained athletes (sprinters and skiing racers).

Method

A simple method to measure, in field conditions, the leg stiffness during maximal bouncing was used on twenty-eight sprinters, and twenty-nine skiing racers. In addition, the mechanical power called reactive power was calculated according to the method proposed by Bosco. The relationship between stiffness and power was observed in the different groups.

Results

The value of stiffness obtained was 29,866 ± 7372 N.m⁻¹. The power was equal to 52.33 ± 8,72 W.kg⁻¹. The main result of this study was that a relation between stiffness and power was obtained only in the sprinters (r² = 0,68, P < 0,001). This result stressed the influence of the sport speciality on the stiffness control.

Conclusion

The power measured during maximal bouncing, called reactive power is correlated with the leg's stiffness when subjects are trained to produce power in similar conditions. No correlation was obtained in skiing racers. The stiffness measurement was then a complementary test in the physical evaluation of the athletes.     

Effets d'une complémentation nutritionnelle en vitamines et minéraux sur la chute de force et les marqueurs biologiques consécutifs à un exercice excentrique chez des personnes âgées

Purpose

The effects of vitamins and minerals complex supplementation on maximal voluntary contraction decrease (FMV) and biological markers following an eccentric exercise at old people.

Method

Sixteen elderly subjects took either placebo (Pl group) or vitamins and minerals (Isoxan Senior, NHS, Rungis, France) (group S) for 21 d before an eccentric exercise and for 3 d after the exercise. The FMV and surface EMG activity (RMS) of the vastus lateralis (VL), vastus médialis (VM) and rectus fémoris (RF) were recorded before (Pre), immediately after (Post), 24 h (Post 24) and 48 h (Post 48) after the exercise. CCVThe creatine kinase (CK), lactate déshydrogénase, malondialdéhyde, and tumor necrosis Factor (TNFα) levels were analyzed.

Results

The reduced MVC (S: 11,2 ± 4,8%; Pl: 17,8 ± 10,4%, P < 0,01) after exercise was associated with a significant reduction in RMS VL, RMS VM and RMS RF values for both groups. A faster FMV recovery appeared at 48 h for the S group (P < 0.05). CK and TNFα values increased in post-exercise.

Conclusion

A dietary supplementation of a vitamin and mineral complex does not attenuate the loss of contractile function immediately after the running exercise, and it may accelerate the recovery of maximal force capacity after 48 h by limiting the post-exercise pro-inflammatory processes.     

Puissance critique de l’enfant prépubère et de l’adulte

Aim

The aim of the study was to compare aerobic and anerobic abilities of prepubertal children and adults with the critical power concept.

Methods

Sixteen children (10.3 ± 0.9 years) and 15 adults (23.5 ± 3.6 years) performed five tests: a maximal-graded test and four constant load exercises until exhaustion. Critical power (CP) and anaerobic-work capacity (CTA) were determined from the power-1/time (P-t) linear relationship.

Results

Determination coefficients for P-t were 0.94 ± 0.05 in children and 0.96 ± 0.04 in adults. PC values were significantly (p < 0.01) lower in children (2.7 ± 0.4 W/kg) than in adults (3.1 ± 0.3 W/kg). CTA values were significantly (p < 0.001) lower in children (136.4 ± 50.8 J/kg) than in adults (247.1 ± 45.7 J/kg).

Conclusion

Satisfying determination coefficients for CP and CTA were found in children and adults. Children have a lower CP and CTA than adults. This result is in accordance with literature.     

Uchi-komi avec charge,une approche physiologique d'un nouveau test spécifique au judo

Objective

The aim of this study was to elaborate and validate a specific test to evaluate the physical condition of judo players.

Subjects and methods

Twenty-three volunteers, males, aged 22 ± 3.62 years old took part in our experiment. They did the progressive test of Leger et al. (1984), vertical Jump test (Sargent test), Australian shuttle run test and a specific judo test.

Results

The observed results showed significant correlations between muscular power and the number of Uchi-komi on the judo test reference scale (R = 0.52, P < 0.01). Furthermore, there were other correlations between the number of Uchi-komi at the two first sets of specific judo test and the anaerobic power represented by the distance covered in 30s at the Australian shuttle test (R = 0.86, P < 0.01), also between the anaerobic capacity represented by the whole distance covered and the total number of Uchi-komi achieved at the judo test (R = 0.88, P < 0.01).

Conclusion

The test reproduces the physiological characteristics of judo fight. It is a good indicator of the judoka's physical fitness and their cardiovascular adaptation in a physical effort.     

Effet d’une hyperventilation volontaire préexercice sur la performance lors de l’épreuve de Wingate

Aim

To determine the effect of a preexercise hyperventilation (HV) on performance measured during the Wingate test.

Protocol

Seven subjects realized the Wingate test whether in normal condition or after the realization of six maximal respiration cycles realized in 30 s. Gas exchanges were recorded breath by breath throughout the test.

Results

Pic power measured during the test was not significantly different after HV. In opposite, the fatigability index (FI) was significantly higher after HV.

Conclusion

A HV does not affect maximal power, but seems to reduce aerobic contribution, which may explain the higher FI observed after HV.     

Effet d'un entraînement en endurance sur les concentrations de l'IGF-1 plasmatique chez le rat

Introduction

The aim of this study was to determine the effects of endurance training on IGF-1, corticosterone and insulin levels in male sedentary and trained rats.

Facts

IGF-1 concentrations decrease after training (p < 0.05), those of corticosterone increase (p < 0.01) whereas insulin levels remain stable.

Conclusion

A short period of endurance training leads to catabolic state with a decrease in IGF-1 concentrations and increase in corticosterone levels.     

Cinétique de la consommation d’oxygène chez le cycliste amateur

Aims

Study was to analyze the relationship between oxygen uptake and power output in amateur cyclists before and after threshold corresponding to a blood lactate concentration of 4 mmol/l.

Methods

We evaluated 109 subjects and they were divided according to age, cycling speciality, level and period. Each subject performed an incremental exercise test (50 W per 3 min) until exhaustion on an electromagnetically braked cycloergometer. Gas exchange data were continuously analyzed and recorded using an automated breath by breath system. Mean values of oxygen uptake were taken during the last minute of each stage in order to build and calculate the regression equations.

Results

The total sample presents an oxygen–kinetic deflection after lactate threshold, with the slope before threshold significantly higher (P < 0.001) than the slope after threshold. This indicates an absence of linearity. Considering the level, the slope and intercept before threshold of the national group presented significantly lower values than regional cyclists. For speciality, the slope before threshold is significantly lower in mountain bike group compared to road. Slope's analyse before and after lactate threshold could present complementary criteria for a good discrimination in comparison with classic concepts used during an incremental exhaustive test.     

Évolution des paramètres physique et anthropométrique de jeunes rugbymen de haut niveau sur une saison sportive

Introduction

The objective of the study is to measure the evolution of the anthropometric and physical parameters in young elite rugby players during one rugby league season.

Results

This study shows an enhancement of the aerobic and lactic anaerobic performances in the first six months of the preparation. Therefore, these aptitudes decrease in April. There is no modification of the lactic anaerobic performance during the season.

Conclusion

This study shows the difficulty to organise the training planification during the winter period for the elite players. The reason for the rugby league season fatigue has yet to be defined and will be the purpose of a future study.     

Compression élastique externe et fonction musculaire chez l'homme

Aims

This article reviews the actual knowledge about the use of compression tights and stockings and their effects on muscle haemodynamics during exercise.

Current knowledge

Some questions are still remaining regarding repeated muscular exercise-induced deleterious effects on veins' shears and valves. These effects can be diminished with the use of compression tights or stockings, in order to enhance venous function and improve muscle haemodynamics.

Points of view and plans

The use of compression tights in running activity does not seem to directly enhance the performance per se, but has an effect on muscle function during and after an exercise. This could in part account for a possible decrease in recovery times. Further studies are needed to evaluate the positive effects of these tights during and after an exercise.

Conclusion

Regarding venous function and muscle haemodynamics the use of compression tights is beneficial. However, in order to avoid high pressure deleterious effects, healthy subjects' vascular physiology has to be taken into account when developing compression tights.     

Aspects biologiques des interactions de l’exercice et de la récupération

Subject

The use of Fourier transform infrared spectrometry technique (FT-IR) as a pitch technique of the biological control of short and intense exercises close to those of Rugby matches.

Material and method

In reference to 28 rugbymen of international level, the biological results of three short and intense exercises and two periods of recovery were analyzed by TF-IR. The exercises are: (1) sprints; (2) 12 × 20 m of swerve running; (3) 6 × 30 s of shuttle run.

Results

Lactate, glucose, urea, and to a lesser degree, triglycerides showed a significant evolution. If the evolution of the two first was in conformity with the literature, the increase of urea probably results from the activation of the purins–nucleotides cycle, whereas the evolution of triglycerides is explained by their probable muscular use during periods of active recovery. Among proteins related to the healthy sportsman, only haptoglobin presents a significant variation difficult to explain whereas CRP, orosomucoid and immunoglobulins A, G and M remain close to their rest values.

Conclusion

With the use of FT-IR technique, it is possible to intervene directly on the pitches of the sporting practice to control the biological incidences and to adjust the loads individually. It is also possible to detect inflammatory and immunological problems related to the biomechanical and physiological stresses.     

Propriétés psychométriques d'un questionnaire de mesure de l'activité physique chez l'enfant scolarisé âgé de six à dix ans : QAPE-semaine

Aims

To elaborate a physical activity questionnaire for school children aged between 6 and 10 years (QAPE-semaine) and to study the psychometric properties (face validity, acceptability, test-retest reproducibility, criterion validity).

Methods

The questionnaire measures physical activities at school, during leisure-time and other activities. Three scores are calculated: variety of physical activities, intensity and sedentary. The questionnaire was pre-tested to study the content validity, and was administered twice to 185 children from two elementary schools. The validity was studied by comparing the results of the questionnaire outcomes with a one day-recall (QAPE-hier) filled out in two occasions (to measure activities during a non school-day and a school-day). The statistic used was the intraclass correlation coefficient (ICC).

Results

The QAPE-semaine was acceptable. The ICC for the reproducibility of variety of physical activities, intensity and sedentary scores were 0.54, 0.47 and 0.68, respectively; and 0.54, 0.56 and 0.64 for the criterion validity of variety of physical activities, intensity and sedentary scores, respectively. All the ICC were significant (P < 0.0001).

Conclusion

The psychometric properties of the QAPE-semaine are satisfactory (moderate to good). Its administration in classes with school professor's help seems however essential.     

Analyse de l'électrocardiogramme et de l'échocardiographie de 181 footballeurs professionnels tunisiens

Objectives

The aim of our work was to determine the frequency of various cardiovascular abnormalities and atypical aspects observed in Tunisian competitive athletes.

Material and methods

Our population was constituted of 181 professional football players (average age 23.1 ± 3.9 years) consulted in “Centre National de la Médecine et des Sciences de Sport” of Tunis with to obtain medical certificate authorizing professional football practice.

Results

Electrocardiogram was strictly normal in 67 players (37%). Twenty-nine players had conduction abnormalities. Repolarisation abnormalities were noted in 20 players. Echocardiography was normal in 129 players (71.3%). Ten cases of valvular heart disease were found. The mean left ventricular end-diastolic diameter was 53 ± 4 mm and the mean left ventricular mass was 202.6 ± 42.7 g. The mean relative wall thickness was 0.380. The left ventricular hypertrophy was present in 42 players.

Conclusion

Cardiovascular abnormalities found in electrocardiogram and echocardiography in the Tunisian professional football players are comparable with those usually observed in elite athletes.     

Application du concept de puissance critique à différentes populations

Aim

The aim of this review was to state the use of critical power concept at different populations and to summarize studies reported data in order to highlight its interest for the aerobic abilities assessement.

Conclusion

The critical power determination is based on times to exhaustion at different exercise intensities. The synthesis of several studies showed that this concept allows to discriminate populations relatively to their aerobic abilities. This is confirmed by its correlation to maximal oxygen uptake and ventilatory threshold in age and fitness different populations.     

Contrairement à une idée reçue,les femmes n’oxydent pas plus de lipides à l’effort que les hommes,mais leur Lipoxmax survient à une puissance plus élevée

Aims

Several studies have shown that women, when they exercise at a given percentage of their aerobic capacity, oxidize more fat than men, thus saving their protein and glycogen stores. We wanted to characterize these differences in terms of levels of transition of balance of substrate oxidation and maximum lipid oxidation flow rate (MLOFR) during exercise.

Methods

Three groups (61 athletes, 196 sedentary and 47 type 2 diabetes mellitus [T2DM], in whom, men and women were matched for age, BMI and physical activity, performed a sub-maximal exercise test with four 6 min steady state steps for measurement of lipid and carbohydrate oxidation by indirect calorimetry. In all three groups MLOFRs are the same in both sexes (2 to 3 mg min⁻¹ kg⁻¹), but among athletes and sedentary women have a curve of oxidation of lipids shifted to the right, a crossover point of use of substrates (PCX, the power for which energy comes mainly from carbohydrates) occurring at a 10–15% higher percentage of VO_2max (p < 0.01). In DT2 this shift is no longer significant. The point of maximal lipid oxidation (Lipox_max) also occurs at a higher percentage of VO_2max (athletes: 44.27 ± 15.97% theoretical VO_2max versus 31.25 ± 15.66% in men, p < 0.001; sedentary: 50.29 ± 18.66% among women versus 36.75 ± 15.22% in men, p < 0.01; for T2DM these levels (42.8 ± 2.4 to 39.8 ± 3.7%) are not significantly different.

Conclusion

Gender-related differences are found on carefully matched subgroups, but are far to be major. They reflect a right shift by 10 to 15% of the curve of lipid oxidation as a function of VO_2max, while rates of oxidation at the Lipox_max do not differ between genders. In other words, women do not oxidize more lipids at exercise, but their ability to oxidize them reaches a maximum at a higher percentage of VO_2max. This discrepancy seems to disappear in T2DM.     

La technique de Didier Patte dans les luxations récidivantes de l’épaule : notre expérience à propos de 35 cas avec un suivi d’une dizaine d’années

Aims

Authors report their personal experience on the surgical treatment of repeated anterior shoulder dislocations, using an anterior bone block in accordance with the procedure suggested by Didier Patte.

Results

From the year 1988 and during 10 years, 35 patients suffering from repeated anterior shoulder dislocations were surgically treated by this procedure. It was appropriate to retrospectively review the clinical and functional outcomes after Patte repair for recurrent anterior glenohumeral instability. The mean follow-up was approximately 10 years, with a mean percentage of 75% for the observance. There was no recurrence after surgery. Moreover, 88% of patients had good outcomes, according to the scale suggested by Butel et al., with total resumption of work and physical activities. The occurrence of chronic complication such as osteoathrosis was scarce (only one case for the series), while 20% of subjects showed apprehension during some specific shoulder movements.

Conclusion

In order to expect best functional outcomes, the choice of the surgical procedure should take into account the extent of initial injury. Considering these ground requirements, the Patte procedure seems to provide very satisfactory long-term functional outcomes.     

Analyse de variables permettant la détermination du niveau d'un cycliste

Aims

We aimed to define a mathematical model allowing to foresee the level of a cyclist.

Methods

One hundred (and) six cyclists were classified according to their level and some of their physiological characteristics were measured with the threshold (4 mmol of lactate) and with the maximum values of their oxygen flow.

Results

To the threshold, power, lactatemy, age and size allow to foresee the level with an error rate of 27% ; to the maximum values, the criteria are development, flow in oxygen, lactatemy and age (error rate of 31%).

Conclusion

These results indicate that our mathematical model allows to envisage the level.     

Extension du modèle puissance–temps limite pour estimer la production d’énergie aérobie et anaérobie lors de l’exercice intense

Aim

Examine how the modelling of the relation between power and time to exhaustion can provide an estimation of the production of aerobic and anaerobic energy during intense exercise.

Current knowledge

The hyperbolic model made it possible to define the critical power corresponding to the maximal rate of energy renewed by aerobic metabolism. A new model distinguishing the critical power from the maximal aerobic power has been built to estimate more precisely the anaerobic contribution. Data from middle distance runners and subjects tested on cycle ergometer showed a relative contribution of anaerobic metabolism arising from critical power and increasing until around 10 % of total power when aerobic energy production reaches its maximum.

Prospects

Considering the slow component of oxygen uptake would provide a more precise analysis of energy production and transformation during exercise at high intensity.