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.     

Effets d'une restriction hydrique et alimentaire prolongée (ramadan) sur la performance et les réponses cardiovasculaires au cours d'un exercice incrémental en milieu tropical chaud

Backgroung

Previous studies showed that maximal oxygen uptake and maximal heart rate were not different during prolonged fasting (ramadan) compared to normal feeding period. However, the effect of ramadan on the blood pressure response during incremental exercise has not been investigated.

Objective

This study aimed to evaluate the evolution of blood pressure during incremental trial in ramadan period.

Methods

Twelve young trained male aged 24 ± 4 yrs participated as voluntary subjects. Their anthropometric parameters, maximal aerobic power and maximal heart were measured in fasting and in normal feeding periods during incremental trial on cycle ergometer.

Results

No significant difference was observed in any anthropometric parameter. Maximal aerobic power of fasting period was significantly less (P < 0,05) compared to normal feeding. Heart rate at rest, at maximal exercise and during a 15 min period of recovery was not significantly affected. Systolic blood pressure of fasting period at maximal power was significantly lower than during the control period (P < 0,05).

Conclusion

Ramadan negatively influences the capacity of maximal power and cardiovascular response at maximal power.     

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.     

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.     

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.     

Relation entre le five-jump test, l'épreuve de vitesse sur 30 m et la détente verticale

Aim

To study the relationship between the five-jump test (5JT) performance, 30 m sprint test and vertical jump performances.

Synthesis of facts

Thirteen male soccer players (15–16 years olds) performed the following tests: 5JT, 30 m sprint and 3 vertical jumps: SJ, CMJ and Free CMJ. The 5JT was strongly correlated with 30 m sprint (R = 0.83; P < 0.01), the SJ (R = 0.71; P < 0.01), the CMJ (R = 0.84; P < 0.01) and the free CMJ (R = 0.62; P < 0.05). The 5JT is also correlated with the index of explosiveness (R = 0.93; P < 0.01).

Conclusion

The 5JT can be used to evaluate muscular strength and explosivity of lower limbs in young soccer players.     

MMP2 and MMP9 plasma levels as markers of bone remodeling: a study on young male tennis players

Introduction

Our goal is to study the effects of tennis practice in pre-pubescent boys on bone remodeling, by means of enzyme activity involved in balance of matrix remodeling (MMP2 and MMP9).

Results

Mineral bone density has been found higher in the dominant arm (P < 0.0001) as well as MMP2 and MMP9 levels in plasma (P < 0.05).

Conclusion

Tennis practice in children increases bone remodeling, which can be assessed by MMP dosage, in addition of densitometry technique.     

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.     

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.     

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.     

Comparison of pure and hybrid iterative reconstruction techniques with conventional filtered back projection: Image quality assessment in the cervicothoracic region

Objectives

To evaluate the impact on image quality of three different image reconstruction techniques in the cervicothoracic region: model-based iterative reconstruction (MBIR), adaptive statistical iterative reconstruction (ASIR), and filtered back projection (FBP).

Methods

Forty-four patients underwent unenhanced standard-of-care clinical computed tomography (CT) examinations which included the cervicothoracic region with a 64-row multidetector CT scanner. Images were reconstructed with FBP, 50% ASIR-FBP blending (ASIR50), and MBIR. Two radiologists assessed the cervicothoracic region in a blinded manner for streak artifacts, pixilated blotchy appearances, critical reproduction of visually sharp anatomical structures (thyroid gland, common carotid artery, and esophagus), and overall diagnostic acceptability. Objective image noise was measured in the internal jugular vein. Data were analyzed using the sign test and pair-wise Student's t-test.

Results

MBIR images had significant lower quantitative image noise (8.88 ± 1.32) compared to ASIR images (18.63 ± 4.19, P < 0.01) and FBP images (26.52 ± 5.8, P < 0.01). Significant improvements in streak artifacts of the cervicothoracic region were observed with the use of MBIR (P < 0.001 each for MBIR vs. the other two image data sets for both readers), while no significant difference was observed between ASIR and FBP (P > 0.9 for ASIR vs. FBP for both readers). MBIR images were all diagnostically acceptable. Unique features of MBIR images included pixilated blotchy appearances, which did not adversely affect diagnostic acceptability.

Conclusions

MBIR significantly improves image noise and streak artifacts of the cervicothoracic region over ASIR and FBP. MBIR is expected to enhance the value of CT examinations for areas where image noise and streak artifacts are problematic.     

The performance of MRI in detecting subarticular bone erosion of sacroiliac joint in patients with spondyloarthropathy: A comparison with X-ray and CT

Objective

To assess the sensitivity and specificity of detecting subarticular bone erosion of sacroiliac (SI) joint in patients with spondyloarthritis (SpA) using MRI three-dimensional water selective balanced steady-state free precession sequence (3D-WS-bSSFP) and T1-weighted (T1W) sequence.

Materials and methods

Radiography, CT and MRI of SI joint from 43 SpA patients were retrospectively analyzed. MRI examination sequences include T1W, short tau inversion recovery (STIR) and 3D-WS-bSSFP. Two radiologists, blinded to clinical data, independently determined bone erosion at bilateral sacral and iliac sides of the SI joint on radiography, CT, T1W and 3D-WS-bSSFP respectively. X² test was used to compare the sensitivity of detecting bone erosion among different diagnostic methods.

Results

Of the 86 sacral and 86 iliac articular surfaces from the 43 cases, radiography, CT, MRI T1W and 3D-WS-bSSFP showed the presence of bone erosion in 40, 74, 50 and 71 articular surfaces respectively. CT and MRI 3D-WS-bSSFP demonstrated similar sensitivity (x² = 0.11, P = 0.74), and both were superior to radiography (x² = 15.17, P < 0.01 and x² = 12.78, P < 0.01, respectively) and T1W (x² = 7.26, P < 0.01 and x² = 5.62, P < 0.05). Using CT diagnosis as the gold standard, the sensitivity and specificity of detecting bone erosion for MRI 3D-WS-bSSFP and T1W sequences were 91.8%, 96.9%, and 60.8%, 94.9% respectively.

Conclusion

MRI 3D-WS-bSSFP sequence is associated with short scanning time, zero ionizing radiation, high sensitivity and specificity of displaying the subarticular bone erosion of SI joints in patients with SpA. Therefore, it can be considered an alternative to CT.     

90°-Flip-angle three-dimensional double-echo steady-state (3D-DESS) magnetic resonance imaging of the knee: Isovoxel cartilage imaging at 3 T

Purpose

The purpose of this study was to investigate whether 3D-double echo steady state (3D-DESS) with improved contrast by setting the FA (Flip angle) at 90° is useful in 3D isotropic cartilage imaging of the knee at 3 T.

Materials and methods

Imaging was performed in 10 healthy volunteers using 3 methods: with 3D-DESS using FA of 25° and 90°, and with true fast imaging with steady-state precession (True-FISP). The signal-to-noise ratio (SNR) of the synovial fluid and cartilage, and contrast-to-noise ratio (CNR) were measured, and mean values were compared. Visual assessment of artifacts was performed with the cartilage divided into 6 regions.

Results

There were no significant differences in synovial fluid SNR in the comparison between FA-90° 3D-DESS and True-FISP (P = 0.364). A significantly higher cartilage SNR was observed with FA-90° 3D-DESS than with True-FISP (P = 0.031). There were no significant differences in synovial fluid-cartilage CNR between FA-90° 3D-DESS and True-FISP (P = 0.892). In the evaluation of artifacts, FA-90° 3D-DESS imaging showed a significantly higher score than True-FISP imaging in the patella and trochlea cartilage (P < 0.001, P < 0.002).

Conclusions

FA-90° 3D-DESS is useful in 3D isotropic cartilage imaging of the knee at 3 T.     

Effets d’un exercice de type anaérobie sur le statut antioxydant enzymatique au cours de la récupération chez les judokas

Aim

To evaluate the effect of the anaerobic exercise on the enzymatic antioxidant statute in judokas’ regional level, because the effects of anaerobic exercise on the free radicals and antioxidants are relatively rare and have some divergences.

Materials and methods

We made this study on ten male judokas (age = 18.1 ± 1.6 years; weight = 77.2 ± 11.6 kg; height = 176.4 ± 4.6 cm), which carried out 30 seconds anaerobic capacity test (Wingate test). Blood samples were taken, by an intravenous catheter, at rest (R), immediately after the Wingate test (P0) then five minutes later (P5), 10 minutes later (P10) then 20 minutes later (P20). The measured parameters are: the superoxide dismutase (SOD), the glutathion peroxidase (GPx) and the total antioxidant statute (SAT).

Results

The concentration of the SOD increases significantly (p < 0.05) at (P0); and regains the baseline values at (P20). The concentration of GPx increases significantly (p < 0.05) in (P0); in (P10) GPx reaches the baseline values. No significant effect of the anaerobic exercise was observed on the concentration of the SAT. Positive correlation was observed between the SOD and GPx to p < 0.05.

Conclusion

The anaerobic exercise modifies the activity of the antioxidant enzymes with different kinetics.     

T2-weighted MR imaging of the liver: Qualitative and quantitative comparison of SPACE MR imaging with turbo spin-echo MR imaging

Objective

To qualitatively and quantitatively compare T2-weighted MR imaging of the liver using volumetric spin-echo with sampling perfection with application-optimized contrast using different flip angle evolutions (SPACE) with conventional turbo spin-echo (TSE) sequence for fat-suppressed T2-weighted MR imaging of the liver.

Materials and methods

Thirty-three patients with suspected focal liver lesions had SPACE MR imaging and conventional fat-suppressed TSE MR imaging. Images were analyzed quantitatively by measuring the lesion-to-liver contrast-to-noise ratio (CNR), and the signal-to-noise ratio (SNR) of main focal hepatic lesions, hepatic and splenic parenchyma and qualitatively by evaluating the presence of vascular, respiratory motion and cardiac artifacts. Wilcoxon signed rank test was used to search for differences between the two sequences.

Results

SPACE MR imaging showed significantly greater CNR for focal liver lesions (median = 22.82) than TSE MR imaging (median = 14.15) (P < .001). No differences were found for SNR of hepatic parenchyma (P = .097), main focal hepatic lesions (P = .35), and splenic parenchyma (P = .25). SPACE sequence showed less artifacts than TSE sequence (vascular, P < .001; respiratory motion, P < .001; cardiac, P < .001) but needed a longer acquisition time (228.4 vs. 162.1 s; P < .001).

Conclusion

SPACE MR imaging provides a significantly increased CNR for focal liver lesions and less artifacts by comparison with the conventional TSE sequence. These results should stimulate further clinical studies with a surgical standard of reference to compare the two techniques in terms of sensitivity for malignant lesions.     

The effects of different intensity walking programs on serum blood lipids,high-sensitive C-reactive protein,and lipoprotein-associated phospholipase A2 in premenopausal women

Aim

This study examined the effects of 12 weeks of walking programs on serum lipids, high-sensitive C-reactive protein, and lipoprotein-associated phospholipase A2.

Methods

Twenty-six pre-menopausal women (30–49 years) completed 12 weeks of walking programs either at moderate or high intensity (50–55%, 70–75% maximum heart rate reserve, respectively). Estimated maximal oxygen consumption was assessed with a 2-km walking test; body composition, blood lipids, high-sensitive C-reactive protein, and lipoprotein-associated phospholipase A2 were measured before and after the study.

Results

Maximal oxygen consumption increased, favoring high-intensity group; body weights, percent body fat (p < 0.01) and body mass index (p < 0.05) decreased in both exercise groups. There were no significant changes in the measured blood lipids in any of the groups, except for a significant reduction in low-density lipoprotein-cholesterol in high-intensity group (p < 0.05). High-sensitive C-reactive protein and lipoprotein-associated phospholipase A2 levels reduced significantly in high-intensity (p < 0.01) and moderate-intensity (p < 0.05) groups, which were also different from the changes in the control group.

Conclusion

Walking programs with different intensity result in favorable changes; however, for protective effects against cardiovascular diseases, high-intensity walking may be advised due to greater reductions in low-density lipoprotein-cholesterol, and high-sensitive C-reactive protein and lipoprotein-associated phospholipase A2.     

Lingering fat signals with CHESS in simultaneous imaging of both hands can be improved with rice pads in both 1.5 T and 3.0 T

Objectives

To investigate whether rice pads can eliminate lingering fat signals of the complex surface shape of both hands that occur with chemical shift selective (CHESS) at 1.5 T and 3.0 T.

Materials and methods

T1-weighted images were obtained with CHESS using 1.5 T and 3.0 T systems. The same imaging parameters were used with and without rice pads on the coronal plane of both hands in 10 healthy volunteers. The fat-suppression effects were classified into four categories and scored for images, and visual evaluations were performed by one radiologist and one radiologic technologist.

Results

At 1.5 T, the mean evaluation score was 1.55 for images obtained without rice pads and 3.50 for images obtained with rice pads. At 3.0 T, the mean evaluation score was 1.10 for images obtained without rice pads and 3.20 for images obtained with rice pads. With both systems, images obtained with the rice pads showed significantly better fat suppression effects than images obtained without rice pads (P < 0.0001, P < 0.0001).

Conclusions

It was confirmed that lingering fat signals are eliminated and good fat-suppressed images are obtained with the use of rice pads at 1.5 T and 3.0 T. Rice pads are therefore useful with at 1.5 T and 3.0 T, which are currently becoming more widely used.     

Diagnostic yield of combined magnetic resonance spectroscopy and diffusion weighted imaging in intracranial neoplasms

Purpose

Our intention was to evaluate the role of combined diffusion magnetic resonance imaging and spectroscopy in diagnosis and grading of brain tumors.

Materials and methods

Ninety-three included cases underwent magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) of the brain lesion, stereotactic or open biopsies and histopathological examination. MRI protocol included DWI and calculated ADC values. Multivoxel MRS spectroscopic technique (MVS) was used and all MRS metabolic parameters were obtained.

Results

High grade tumors had significantly lower ADC values than low grade tumors (P < 0.001). ADC values were the lowest in lymphoma (0.54 × 10⁻³ mm²/s) and the highest in craniopharyngioma (1.9 × 10⁻³ mm²/s). MRS revealed a statistically significant difference in CHO/NAA and CHO/Cr ratios between low and high grade tumors with P < 0.01 and P < 0.001, respectively. The mI/Cr ratio and presence of lactate, lipid and taurine also aided in differentiation and grading of brain tumors. The overall MRI/MRS sensitivity and specificity were 91%, 90.5%, respectively.

Conclusion

MRS has a robust diagnostic accuracy in cases of well defined high or low grade brain neoplasms. ADC value had the ability to confirm and differentiate low from high grade tumors in many situations where there were diagnostic confusions with MRS due to borderline values.     

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.