Locomotor performance in highly-trained young soccer players: does body size always matter?

To examine the effects of body size on locomotor performance, 807 15-year-old French and 64 Qatari soccer players participated in the present study. They performed a 40-m sprint and an incremental running test to assess maximal sprinting (MSS) and aerobic speeds, respectively. French players were advanced in maturity, taller, heavier, faster and fitter than their Qatari counterparts (e.g., Cohen's d=+1.3 and + 0.5 for body mass and MSS). However, when adjusted for body mass (BM), Qatari players had possibly greater MSS than French players (d=+0.2). A relative age effect was observed within both countries, with the players born in the first quarter of the year being taller, heavier and faster that those born during the fourth quarter (e.g., d=+0.2 for MSS in French players). When directly adjusted for BM, these MSS differences remained (d=+0.2). Finally, in both countries, players selected in National teams were taller, heavier, faster and fitter than their non-selected counterparts (e.g., d=+0.6 for MSS in French players), even after adjustments for body size (d=+0.5). Differences in locomotor performances between players with different phenotypes are likely mediated by differences in body size. However, when considering more homogeneous player groups, body dimensions are unlikely to substantially explain the superior locomotor performances of older and/or international players.

The biological and metabolic adaptations to 12 months training in elite rowers.

We studied the effects of a twelve months endurance-training program on exercise-induced change in blood contents in thirteen rowers. A standardized testing-session (18 km rowing at 80 % of VO2max) was performed 19 times during the training program. Capillary blood samples were taken at rest and immediately post-exercise to analyse a wide range of serum concentrations. During exercise, glucose and lactate concentrations stabilized after only five training weeks and did not evolve from that point. Transport and hepatic protein concentrations increased with exercise up to the 15th week (p = 0.03), and remained stable from that point (p = 0.02). Evolution of exercise-induced change in alpha 1 -acid glycoprotein concentration revealed protein metabolism adaptations to training. Change in alpha 1 -acid glycoprotein concentrations were exactly opposite to that of urea and alpha 1 -antitrypsin (p = 0.01 and 0.002, respectively). Immunoglobulin concentrations exhibited important increases up to the 6th training week (p < 0.05), and a global stabilization was observed from that point. However, analysis of IgG subclasses highlighted significant changes that could not be found with the study of total IgG concentrations. Evolution of the exercise-induced change in Apo-A 1 /Apo-B concentrations ratio was also more informative about lipid metabolism than the Apo-A 1 and Apo-B concentrations taken individually. Indeed, evolution of metabolic changes during exercise should be carefully monitored during training to avoid interpretative errors on the training status of athlete.

Discriminant serum biochemical parameters in top class marathon performances.

Blood chemical parameters were analyzed by Fourier-transform infrared spectrometry (notably for determining the concentrations of glucose, lactate, urea, glycerol, triglycerides, and proteins) in 14 top-class marathon runners (133.7+/-4.1 min at marathon, 10.1% difference between extremes) who performed a 10-km run at their individual marathon velocity. Marathon performance level was correlated to glycemia increase during exercise (9% difference between extremes; r=0.93; p<0.005). The best marathon runners presented longer and/or less unsaturated blood fatty acids during exercise (17% difference between extremes; r=0.89; p<0.01), suggesting an improved fatty acid selectivity for muscular metabolism. The marathon performance level was also found correlated to a decrease of blood triglycerides during exercise (r=20.95; p<0.003) and to a proportional glycerol concentration increase (11% difference between extremes; r=0.94; p<0.005). The best marathon runners presented higher amino acid blood delivery (r=0.88; p<0.01), which was correlated to an apparent protein catabolism. These results show that the best runners have enhanced both carbohydrate, lipid, and amino acid metabolisms to improve energetic supply to skeletal muscle during exercise.

[Clinical diagnosis of overtraining using blood tests: current knowledge]. / L'étiologie clinique du surentraînement au travers de l'examen sanguin: état des connaissances.

PURPOSE: Overtraining results from an imbalance between training load-induced fatigue and organism's recovery abilities. Its etiology is complex and to date there is no useful clinical diagnostic tool. The purpose of this review is to discuss the blood chemistry parameters potentially useful for diagnosing overtraining in athletes. CURRENT KNOWLEDGE AND KEY POINTS: Chronic alterations of the myocyte structure may cause high plasma concentration increases of myoglobin, troponin I and creatine kinase enzyme, resulting in chemical and/or mechanical aggression. Monitoring reactive oxygen species' activity appears to be a good tool for evaluation of the metabolic stress level experienced by skeletal muscles. In energetic metabolism, a succession of chronic glycogen depletions might change the use of amino acids and lipids, inducing transient but severe hypoglycemia during exercise. A higher oxidation of circulating glutamine might cause immunosuppression (lower reactivity to inflammations and cellular traumatisms), inhibiting alarm signals during acute training. A higher branched-chain amino acid oxidation might favor free tryptophan's entry into the cerebral area, enhancing serotonin synthesis. As a consequence, asthenia and a loss of sensitivity to muscular and tendon traumatism might appear. Exercise anemia might also be a worsening factor of the physiological situation of the tired athlete, inducing predisposition to overtraining by the lower inflammation reactivity of depleted hepatic and muscular proteins. FUTURE PROSPECTS AND PROJECTS: Early diagnosis of overtraining diagnosis may be established only from a battery of analyses, which should include the whole of the potential parameters. These remain unpredictable and do not allow systematic determination of new cases. Only a longitudinal study of the physiological situation appears to allow the necessary conditions for detecting overtraining in the early stages of its process for each subject.

Differentiation of populations with different physiologic profiles by plasma Fourier-transform infrared spectra classification.

The pathologic condition of a patient presenting a metabolic disease can change rapidly, and a variety of pathologic conditions are possible. Plasma Fourier-transform infrared (FT-IR) spectra were used to differentiate patients with type 1 diabetes, healthy subjects, and endurance-trained rowers. Analytic and classification methods that use the same plasma FT-IR spectra are described. Complete spectra (4000 to 500 cm(-1)) classifications led to a differentiation between most patients with type 1 diabetes and other subjects but not between control and trained subjects. Classification of defined absorption regions of spectra allowed different metabolic distinctions between populations. These were performed on the amide I and II absorption regions of proteins (1720 to 1480 cm(-1)); on the nu=CH, nu(as)CH(2), and nu(as)CH(3) absorption regions of lipids (3020 to 2880 cm(-1)); and on the nuC-O absorption region of saccharides (1300 to 900 cm(-1)). A classification that uses a combination of four absorption regions-nu=CH (3020 to 3000 cm(-1)), nu(as)CH(3) (3000 to 2950 cm(-1)), nuC-O (amide I: 1720 to 1600 cm(-1)), and nuC-O (carbonyle: 1300 to 900 cm(-1))-led to the formation of three exclusive clusters that comprised the defined populations. FT-IR spectroscopy is an exciting technique that allows a versatile approach to biologic samples from which analytic and statistical methods might be used for metabolic profile characterization and evaluation.

Plasma protein contents determined by Fourier-transform infrared spectrometry.

BACKGROUND: Fourier-transform infrared (FT-IR) spectrometry has been used to measure small molecules in plasma. We wished to extend this use to measurement of plasma proteins. METHODS: We analyzed plasma proteins, glucose, lactate, and urea in 49 blood samples from 35 healthy subjects and 14 patients. For determining the concentration of each biomolecule, the method used the following steps: (a) The biomolecule was sought for which the correlation between spectral range areas of plasma FT-IR spectra and concentrations determined by comparison method was greatest. (b) The IR absorption of the biomolecule at the most characteristic spectral range was calculated by analyzing pure samples of known concentrations. (c) The plasma concentration of the biomolecule was determined using the FT-IR absorption of the pure compound and the integration value obtained for the plasma FT-IR spectra. (d) The spectral contribution of the biomolecule was subtracted from the plasma FT-IR spectra, and the resulting spectra were saved for further analyses. (e) The same method was then applied to determining the concentrations of other biomolecules by sequentially comparing the resulting FT-IR spectra. RESULTS: Results agreed with those obtained by clinical methods for the following biomolecules when analyzed in the following order: albumin, glucose, fibrinogen, IgG(2), lactate, IgG(1), alpha(1)-antitrypsin, alpha(2)-macroglobulin, transferrin, apolipoprotein (Apo)-A(1), urea, Apo-B, IgM, Apo-C(3), IgA, IgG(4), IgG(3), IgD, haptoglobin, and alpha(1)-acid glycoprotein. CONCLUSION: FT-IR spectrometry is a useful tool for determining concentrations of several plasma biomolecules.

FT-IR spectroscopy utilization to sportsmen fatigability evaluation and control.

PURPOSE: A longitudinal biological study of 20 elite rowers was performed using capillary blood (serum) FT-IR spectra to evaluate their training load adaptations and fatigue. METHODS: Difference spectra (rest serum spectra subtracted to exercise serum spectra) were used to evaluate subjects' metabolic response to exercise. Spectra classifications were used for serum contents differentiation on the basis of biomolecular absorption. RESULTS: For two subjects, several metabolic differentiations were observed. These started with sugars metabolism on the fifth training week, followed successively by lipid metabolism and protein metabolism, when overtraining was clinically diagnosed. Several weeks further into the training program, the same onset of metabolic differentiations was observed for eight other subjects. When differentiations reached lipid metabolism, they were asked to reduce their training loads. Unlike the overtrained subjects, a rapid recovery was observed (3 vs 22 wk) and metabolism alterations disappeared. CONCLUSION: The fatigability limit in sportsmen seemed to be situated at a certain level of metabolic stress, beyond which a rapid overtraining process recover was no longer possible.

Perspectives in the utilisation of Fourier-transform infrared spectroscopy of serum in sports medicine: health monitoring of athletes and prevention of doping.

Doping prevention is mainly directed to providing information on the dangers of doping to young athletes and to every profession concerned with athletic performance. Unfortunately, repression is also necessary in the fight against doping. Measurement of performance-enhancing drugs is complex, partly because of the large number of prohibited substances. A number of sophisticated analytical techniques are increasingly being used to provide the maximum detection time window. However, the effectiveness of methods to separate exogenous from endogenous biological molecules and the cost of antidoping analyses makes controls invalid or impossible. Moreover, most athletes, because of the metabolic and psychological stresses caused, legitimately refuse blood testing. It is becoming crucial to introduce new methods in the form of longitudinal health monitoring, since this is probably the most effective tool to prevent the use of doping agents when athletes become overtrained and/or overstressed. This paper describes new methods using Fourier-transform infrared spectroscopy to analyse serum from 50 microl samples of capillary blood. This technique has been shown to allow determination of the concentration of a wide range of biological molecules in a single microsample with clinically useful accuracy, and to provide a 'discriminatory biomolecular profile' to differentiate individuals on the basis of their physiological status. A specific application of this methodology is to perform longitudinal health monitoring in athletes, allowing prevention of overtraining. It is proposed to apply such methods in longitudinal studies for health monitoring and prevention of doping.

Glucose and lactate concentration determination on single microsamples by Fourier-transform infrared spectroscopy.

This study is the first to assess the analytic potential of Fourier-transform infrared (FT-IR) spectroscopy in determining exercise-induced metabolic changes, such as glucose and lactate serum concentrations, with single 50 microL blood microsamples. One-hundred ninety-eight capillary blood samples were taken at rest (rest serum) and after rowing exercises at different intensities (exercise serum) to obtain a wide range of lactate concentrations. A quantitative method is described with FT-IR spectroscopy involving only dilution and dessiccation of serum samples. Within serum spectra, an absorption band was strongly specific of glucose (1033 cm(-1)) that allowed the determination of its concentration (r = 0.97; P < .001 with reference values). Once we had substrated measured glucose absorption in serum spectra, one other absorption band seemed to be specific for lactate (1127 cm(-1)), which allowed the determination of the concentration of this metabolite (r = 0.96; P < .001 with reference values). The convenience of a capillary blood sampling with the strong accuracy of FT-IR measurements is of particular interest for medicinal and biologic concerns.

Determination of glucose in dried serum samples by Fourier-transform infrared spectroscopy.

BACKGROUND: Practical improvements are needed to allow measurement of glucose concentrations by Fourier- transform infrared (FT-IR) spectroscopy. We developed a new method that allows determination of the glucose concentration in dried sera. METHODS: We studied 32 serum samples after fourfold dilution and desiccation before FT-IR analyses on a spectrometer operated at a resolution of 2.0 cm(-1). We integrated all spectral windows at the surface of the spectrum in the C--O region. For comparison, glucose was measured in the sera by a glucose oxidase method. RESULTS: One peak within the spectrum was most specific for glucose (997-1062 cm(-1)). Its surface integration showed a strong relationship with reference data (r = 0.998; P <0.001). FT-IR analyses of five glucose solutions were performed to determine its specific absorption at the same peak. In this way, glucose concentrations in serum spectra could be measured. For the first time while using FT-IR spectroscopy, no manipulation of spectra nor use of internal standard was necessary to obtain results in high accordance with glucose concentration measured by a conventional (glucose-oxidase) method (S(y|x) = 0.25 mmol/L; r = 0. 998). CONCLUSIONS: FT-IR spectroscopy appears to be an easy and accurate method to determine glucose concentration and could be widely used to simultaneously identify and quantify several metabolites in biological fluids or tissues.

Physiological aspects of swimming performance for persons with disabilities.

The purpose of this study was to evaluate the various factors involved in the performances of three groups of swimmers with disabilities. These factors were average VO2max (Av-VO2max) measured during swimming and gliding factors measured by the passive drag. Thirty-four swimmers with disabilities were assigned into three groups ranging from more disabilities to fewer disabilities. The first group (G I) included 13 subjects in wheelchairs, the second group (G II) 10 subjects walking with technical aids, and the third group (G III) 11 swimmers with disabilities walking without any help. For G I, the performances and Av-VO2max were lower (P < 0.05) than for G II and G III while the passive drag was higher than for G III (P < 0.05). The performances, Av-VO2max, and passive drag were not statistically different between G II and G III. Some of the swimmers had a pronounced amyotrophia of the lower extremities (i.e., reduced volume of inactive muscles). The height from the top of the head to the beginning of the bilateral amyotrophia was called "height without amyotrophia" (HWA). In the whole group, passive drag was not related to the mass or the height but to the ratio mass/HWA (r = 0.71, P < 0.01). However, within each group, passive drag was mainly related to the mass (r = 0.63, 0.78, 0.62, P < 0.01, for G I, G II, and G III respectively). Performances of a 100-m and 400-m swim were mainly related to Av-VO2peak (r = 0.81 and 0.79, P < 0.01, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Echocardiographic assessment of myocardial performance after prolonged strenuous exercise.

To determine the effect of strenuous prolonged exercise on systolic and diastolic left ventricular function, 11 non-elite marathon runners aged 37 +/- 7 years (mean +/- SD) were studied before and during early recovery from a marathon race. Cavity dimensions, wall thickness, and fractional shortening were computed from two-dimensionally guided M-mode echocardiograms. Doppler left ventricular inflow tract recordings were analysed for peak early and late velocities and their ratio. In seven subjects, heart frequency was recorded throughout the race. These subjects ran the marathon at 87 +/- 4% of their maximal heart rate. Left ventricular diastolic dimension was slightly reduced at the end of the race (49.4 +/- 4.2 mm to 47.3 +/- 5.1 mm; P less than 0.05). Fractional shortening remained unchanged, although blood pressure (P less than 0.001) and systolic wall stress (P less than 0.01) were decreased. The left ventricular filling pattern was unchanged, and the ratio of early to late velocities remained constant. These results suggest that the fractional shortening was a result of the opposing effects of changes in preload and afterload. However, the absence of a change in the end systolic dimension, despite a marked reduction in afterload and the occurrence of septal akinesia in one subject after the race could only suggest that strenuous prolonged exercise may alter myocardial performance.

Plasma renin activity, aldosterone and catecholamine levels when swimming and running.

The purpose of this study was to determine the response of plasma renin activity (PRA), plasma aldosterone concentration (PAC) and catecholamines to two graded exercises differing by posture. Seven male subjects (19-25 years) performed successively a running rest on a treadmill and a swimming test in a 50-m swimming pool. Each exercise was increased in severity in 5-min steps with intervals of 1 min. Oxygen consumption, heart rate and blood lactate, measured every 5 min, showed a similar progression in energy expenditure until exhaustion, but there was a shorter time to exhaustion in the last step of the running test. PRA, PAC and catecholamines were increased after both types of exercise. The PRA increase was higher after the running test (20.9 ng AngI X ml-1 X h-1) than after swimming (8.66 ng AngI X ml-1 X h-1). The PAC increase was slightly greater after running (123 pg X ml-1) than swimming (102 pg X ml-1), buth the difference was not significant. Plasma catecholamine was higher after the swimming test. These results suggest that the volume shift induced by the supine position and water pressure during swimming decreased the PRA response. The association after swimming compared to running of a decreased PRA and an enhanced catecholamine response rule out a strict dependence of renin release under the effect of plasma catecholamines and is evidence of the major role of neural pathways for renin secretion during physical exercise.

VO2 peak during free swimming using the backward extrapolation of the O2 recovery curve.

The purpose of this study was to evaluate the accuracy and feasibility of estimating oxygen consumption (VO2) during maximal swimming by using the backward extrapolation (BE) of the VO2 recovery curve to time zero. Two series of experiments were conducted. In the first, the validity of the BE method was ascertained by comparing the VO2 peak values obtained during free swimming (Douglas bag technique) with those estimated by the BE method during recovery after the same tests. These results were also compared with VO2 peak measured during uphill treadmill running. VO2 peak measured during maximal free swimming and estimated by the BE method during the recovery period of that test, were not significantly different. No significant difference was found between VO2 peak uphill treadmill running and free swimming. In the second series of experiments, VO2 peak was measured in each of 28 swimmers during uphill running (conventional method) and during unimpeded swimming using the BE method. The mean value was significantly higher during swimming (mean = 3.37) than during running (mean = 3.23). Seventy-five percent of the subjects had higher VO2 peak during swimming. The swimming speed during maximal swimming effort was 10% higher when the BE method was used then when the same subjects were tested by the conventional Douglas bag technique. The BE method is reliable and valid way to measure VO2 peak in maximal swimming and allows the swimmer to use his specifically trained musculature fully.