There is no anaerobic work capacity replenishment at critical power intensity: An indirect evidence

Aim

This study aimed to test if investigate whether the anaerobic work capacity is replenished while exercising at critical power intensity. Then, a known exercise duration, which demands high anaerobic energy contribution, was compared to intermittent exercise duration with passive and active (cycling at critical power intensity) rest periods.

Methods

Nine participants performed five sessions of testing. From the 1st to the 3rd sessions, individuals cycled continuously at different workloads (P_high, P_intermediate and P_low) in order to estimate the critical power and the anaerobic work capacity. The 4th and 5th sessions were performed in order to determine the influence of anaerobic work capacity replenishment on exercise duration. They consisted of manipulating the resting type (passive or active) between two cycling efforts. The total exercise duration was determined by the sum of the two cycling efforts duration.

Results

The exercise duration under passive resting condition (408.0 ± 42.0 s) was longer (p < 0.05) than known exercise duration at P_intermediate (T_intermediate = 305.8 ± 30.5 s) and than exercise duration performed under active resting conditions (T_active = 304.4 ± 30.7 s). However, there was no significant difference between T_intermediate and T_active.

Conclusion

These results demonstrated indirect evidence that the anaerobic work capacity is not replenished while exercising at critical power intensity.     

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 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.     

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.     

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.     

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.     

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.     

Deux mythes concernant l’exercice chez le diabétique de type 1 : le seuil hyperglycémique de 2,5 g/l de contre-indication à l’effort et le glucose pulse

Aims

We addressed the relevance of two usual beliefs about blood glucose response to exercise in insulin-treated diabetic patients. First, that a pre-exercise blood glucose value exceeding 250 mg/dL means that exercise should be avoided because it will result in worsening of hyperglycemia; second, the prediction of carbohydrate oxidation according to the level of exercise “glucose pulse” may have some value to predict how blood glucose levels will respond to exercise.

Methods

Twenty-four type-1 diabetics (12 men and 12 women, age 19–71 years) treated with basal-bolus or continuous insulin delivery by portable pump performed a steady-state exercise on ergocycle at 50% of their predicted P_max (40–200 W) with measurement of blood glucose levels, blood lactate, and exercise calorimetry. This protocol lowers blood glucose (p < 0.05), with a variable magnitude (−4 to −178 mg/dL [mean: −51 ± 9 mg/dL]), i.e., blood glucose decreased in 21 subjects (87.5%). Carbohydrate oxidation rates do not, however, predict the evolution of blood glucose. Baseline blood glucose G₀ (ranging between 89 and 270 mg/dL, i.e., on average 179 ± 14 mg/dL) was in fact negatively correlated (and not positively) to the variation of blood glucose during exercise (r = −0.462; p < 0.05), so that the higher is G₀ the more blood glucose decreases. When G₀ is greater than 250 mg/dL blood glucose decreased on average by −97 ± 26 mg/dL (p < 0.05). During these steady state bouts of exercise, which clearly decrease blood glucose, oxidation of carbohydrates does not predict the decline in blood glucose (minimizing the interest of the concept of “glucose pulse”), and a value of G₀ greater than 250 mg/dL does not predict exercise hyperglycemia so that it is no longer logic to set this value as a threshold for counter indicating exercise.     

The effect of callisthenic exercise on physical fitness values of sedentary women

Introduction

The purpose of this study was done to determine the effects of a 12-week callisthenic exercise program on some physical and physiological parameters of young, middle-aged and menopausal women.

Synthesis

We studied, during 12 weeks, 172 subjects’ age, height and body weight means were determined. Physical characteristics of Group I were (between19–30 years) 26.72 ± 3.57 years, 158.18 ± 4.66 cm and 71.45 ± 10.32 kg, for Group II (between 31–44 years) were as 41.43 ± 4.69 years, 156.94 ± 5.27 cm and 73,89 ± 10,66 kg, and Group III (between 45–56 years) were as 50.60 ± 4.05 years, 154.45 ± 4.18 cm and 75.51 ± 11.71 kg, respectively. All subjects attended the study, 50 minutes per session, three sessions per week, aerobic and calisthenic exercise programs. The intensity of the exercise was determined by Karvonen method (60 or 70%). There were significant differences in increase among aerobic power, sit-up, push-up, and handgrip strength values in Groups I, II and III. There was a significant difference among Group I, II and III in decreased blood pressure (p < 0.05).

Conclusion

It was determined that physical fitness values had decreased as the age increased. As a result, it can be said that the long-term callisthenic exercises cause the similar positive changes on women at different ages.     

Técnicas de recanalización vertebrobasilar antes de la introducción de las endoprótesis recuperadoras: la reapertura no es sinónimo de buena evolución

Objectives

To evaluate the recanalization rate and clinical outcome three months after endovascular treatment for vertebrobasilar occlusion before the placement of stentrievers.

Material and methods

We reviewed all cases of basilar thrombosis treated with endovascular techniques at our center. We reviewed the clinical outcomes with the main objective of determining the recanalization rate and the secondary objective of evaluating the outcome using the modified Rankin scale (mRS) three months after treatment. We assessed clinical and angiographic variables and correlated them with outcome and complications.

Results

We reviewed a total of 27 consecutive patients (mean age, 58.1 ± 15.5 y; median National Institutes of Health Stroke Scale (NIHSS), 21, interquartile range, 18-29; median Glasgow coma score (GCS) 7, interquartile range, 4-9.5). The mean time between the onset of symptoms and endovascular treatment was 26.3 ± 41.7 hours. Complete or partial recanalization was achieved in 23 (85.1%) patients. Three months after treatment, 16 (59.2%) had died and 6 (22.2%) had good outcome (mRS ≤ 2).

Conclusion

Endovascular treatment achieved a high rate of recanalization of occlusions of the basilar artery. Nevertheless, a high percentage of the patients did not have a good outcome. New materials might improve the prognosis in these patients.     

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.     

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.     

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.     

Diffusion-weighted MRI of the prostate at 3.0 T: Comparison of endorectal coil (ERC) MRI and phased-array coil (PAC) MRI—The impact of SNR on ADC measurement

Purpose

To compare ADC values measured from diffusion-weighted MR (DW-MR) images of the prostate obtained with both endorectal and phased-array coils (ERC + PAC) to those from DW-MRI images obtained with an eight-channel torso phased-array coil (PAC) at 3.0 T.

Methods

The institutional review board issued a waiver of informed consent for this HIPAA-compliant study. Twenty-five patients with biopsy-proven prostate cancer underwent standard 3-T MRI using 2 different coil arrangements (ERC + PAC and PAC only) in the same session. DW-MRI at five b-values (0, 600, 1000, 1200, and 1500 s/mm²) were acquired using both coil arrangements. On b = 0 images, signal-to-noise ratios (SNRs) were measured as the ratio of the mean signal from PZ and TZ ROIs to the standard deviation from the mean signal in an artifact-free ROI in the rectum. Matching regions-of-interest (ROIs) were identified in the peripheral zone and transition zone on ERC-MRI and PAC-MRI. For each ROI, mean ADC values for all zero and non-zero b-value combinations were computed.

Results

Mean SNR with ERC-MRI at PZ (66.33 ± 27.07) and TZ (32.69 ± 12.52) was 9.27 and 5.52 times higher than with PAC-MRI ((7.32 ± 2.30) and (6.13 ± 1.56), respectively) (P < 0.0001 for both). ADCs from DW-MR images obtained with all b-values in the PZ and TZ were significantly lower with PAC-MRI than with ERC-MRI (P < 0.001 for all).

Conclusion

Lower SNR of DW-MR images of the prostate obtained with a PAC can significantly decrease ADC values at higher b-values compared to similar measurements obtained using the ERC. To address these requirements, clinical MR systems should have image processing capabilities which incorporate the noise distribution.     

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.     

T1 mapping for detection of left ventricular myocardial fibrosis in hypertrophic cardiomyopathy: A preliminary study

Purpose

To investigate the diagnostic value of T1 mapping imaging of evaluating fibrosis in patients with hypertrophic cardiomyopathy (HCM).

Materials and methods

21 subjects with HCM and 18 healthy volunteers underwent conventional late gadolinium enhancement (LGE) imaging and T1 mapping imaging. The region of myocardium in HCM is divided into remote area of LGE, peri-LGE, LGE (halo-like LGE and typical patchy LGE). These regions combined with normal volunteers’ myocardium were calculated by the reduced percent of T1 value (RPTV).

Results

The RPTV in healthy volunteers was no significant comparing with that in the remote area of LGE in HCM subjects (3.98 ± 3.19 vs. 3.34 ± 2.75, P > 0.05). There were significant statistical differences in pairwise among the remote area of LGE, peri-LGE, halo-like LGE and typical patchy LGE in the RPTV (P < 0.0001). ROC curves indicated that the T1 mapping imaging has a greater area under the curve comparing with that of traditional LGE imaging (0.975 ± 0.07 vs. 0.753 ± 0.26, P < 0.0001).

Conclusions

HCM has a high prevalence of fibrosis and with varying severity. T1 mapping imaging can be a useful method to evaluate the severity of the fibrosis in HCM.     

Hydrogen MR spectroscopy of neck masses

Purpose

The purpose of this study is to evaluate the role of MR spectroscopy in differentiation between benign and malignant neck masses.

Materials and methods

Thirty-two patients having neck masses underwent routine MRI of the neck as well as Hydrogen 1 (¹H) MR spectroscopy with echo time of 270 ms at 1.5 T. Peak amplitudes of choline (Cho) & creatine (Cr) for each lesion as well as normal appearing muscle of the neck were obtained. Results were compared by using a nonparametric t test.

Results

Thirty-two lesions were included (14 benign) & (18 malignant). Mean value (±standard deviation) was 4.42 ± 0.83 for malignant tumors and 1.93 ± 0.74 for benign tumors. Also spectra were obtained from normal appearing muscles with average Cho/Cr ratio 1.59 ± 0.49. Differences were significant between benign & malignant tumors as well as between malignant tumors & normal appearing muscles (p value < 0.001). No significant difference could be detected between benign tumors & normal appearing muscles (p value = 0.91).

Conclusion

MR spectroscopy should be used in the future as a complementary method to routine MRI to differentiate between benign and malignant lesions.     

Comparison of CT and MRI artefacts from coils and vascular plugs used for portal vein embolization

Purpose

To retrospectively analyze the degree of artefacts in CT and MRI scans caused by coils and vascular plugs used for portal vein embolization (PVE).

Materials and methods

All patients who underwent PVE between July 2011 and December 2012 and received either plug or coil embolization additional to particle embolization were retrospectively analyzed. Artefacts causes by embolization materials were measured in CT and MRI scans following PVE.

Results

The sum of the artefact diameters caused from coils was significantly higher in CT (188.3 ± 26.1 mm) than in MRI T1 (50.5 ± 6.5 mm) or T2 imaging (39.5 ± 9.7 mm) (P < 0.05). In MRI, the diameter in T1 and T2 sequences did not differ significantly (P = 0.977). The sum of the artefact diameters from vascular plugs in MRI T1 sequences (62.5 ± 8.7 mm) was significantly higher than in CT (46.6 ± 4.8 mm; P < 0.05) and MRI T2 sequences (52.8 ± 3.8 mm; P < 0.05).

Conclusion

PVE with particles and vascular plug causes significantly fewer artefacts than PVE with particles and coils on CT scans following embolization, which can be important in the event of vascular complications or in follow-up scans, should the patient become unresectable.