Search

Aim. – The aim of this study was to investigate the influence of training status (sprint or endurance training) on plasma volume variation (ΔPV) in response to the Wingate-test in male subjects.Method. – We compared the ΔPV between 7 male sprinters (S) (20.9 ± 0.6 years), 7 male untrained (NE) (21.4 ± 0.5 years) and 7 male endurance-trained (E) (20.9 ± 0.8 years) in response to a Wingate-test. Hematocrit and plasma lactate were determined at rest and after 5, 10, 20 and 30 min recovery. The ΔPV was determined by the variation of the hematocrit.Results. – As expected, during the Wingate-test, S developed significantly higher performances than E and NE in absolute and relative values (normalized for body mass or lean body mass). Maximal plasma lactate was significantly greater in S (18.1 ± 1.2 mmol l–1) than in E (13.4 ± 0.9 mmol l–1) and in NE (14.2 ± 1.1 mmol l–1). The Wingate-test was associated with a significant decrease in plasma volume. The mean maximal decrease recorded at the end of the exercise was 18.3, 10.2 and 7.9% respectively in S, E, and NE. The ΔPV decrease was significantly higher in S than E and NE at the end of the exercise and after the fifth minute of recovery.Conclusion. – Thus, this study clearly demonstrated that a brief and supramaximal exercise induced a higher plasma volume decrease in sprinters than in endurance-trained or untrained subjects. The responsible factors of this result remained to be clarified. [Copyright &y& Elsevier]

Objective. – To determine the stop of crutches to walk in patients with total knee arthroplasty from the test of maximal gait speed.Method. – 46 patients (73.6 ± 4.6 years) carried out the maximal gait speed test on a 10-meter track, with two crutches, at the 3rd week after a total knee arthroplasty surgery for gonarthrosis. Two groups were separated according to the need of crutches to walk. Various threshold values of maximal gait speed were then determined (ROC curve) to know if this parameter could define the stop of crutches to walk (Predictive value).Results. – Patients able to stop crutches (n = 27) walk faster, than the patients who still need crutches (n = 19), (0.86 ± 0.17 m/s vs 0.65 ± 0.14 m/s ; p < 0.01). According to the ROC curve, two speeds were chosen: 1.11 m/s (9 s) and 0.55 m/s (18 s). A gait speed superior or equal to 1.11 m/s presents a positive predictive value of 86% to authorize to stop crutches. Below 0.55 m/s, the positive predictive value is 83% to keep crutches. Between these two speeds, the test of maximal gait speed does not help the clinician to decide to stop crutches.Conclusion. – The test of maximal gait speed brings a help to decide to stop crutches only for speeds superior to 1.11 m/s. [Copyright &y& Elsevier]

Introduction: Measurement of maximal respiratory pressures against an occlusion has been used for a long time to assess respiratory muscle strength in the follow up of children with respiratory disease. In the early stage of disease this is the main test for diagnosing respiratory muscle involvement and the degree of that involvement. STATE OF KNOWLEDGES: The interpretation of the results is difficult on account of variability of the measurements and of the reference values. The aim of this article is to present, in the form of a literature review, the normal values available and the different determining factors as well as the advantages and limitations of these measurements., Perspectives: The use by all the centres undertaking maximal respiratory pressure measurements in children of methodological techniques similar to those presented in this revue could be the starting point for obtaining an identical range of reference values for all., Conclusion: Age, sex and the level of physical aptitude seem to be the most important determinants of maximal respiratory pressures. However, other methodological factors such as co-operation, training of the child in the performance of the manoeuvres and the type of device and protocol used, will all influence the results. These factors must be taken into consideration in order to diminish, as much as possible, the variability of the maximal pressures obtained.

Introduction: The evaluation of the ventilatory response of children during exercise is essential to determine its role in impaired exercise tolerance. The aim of this review is to describe the variables and the values of maximal ventilatory parameters observed in healthy children in the published literature., State of Art: The maximal ventilation (VEmax) and the tidal volume (VTmax) increase in a linear fashion with age and plateau in boys at 15 years, and in girls at 13 years. The main variables for the parameters connected to volume--VEmax and VTmax--are anthropometric characteristics, in particular, the lean body mass. Most studies show a value of 30 ml.kg(-1) for a VTmax on the total body mass in pre-puberty and a slight increase thereafter. The ventilatory reserves and the VTmax on vital capacity increase with age until respective values of 30% and 50% are reached at 17 years. The maximal parameters connected to time are independent of anthropometric characteristics. The TI/TTOT ratio (inspiratory time to total time of the respiratory cycle) is stable with a value of 0.5. The maximal respiratory frequency decreases slightly with age without differences between the genders., Perspectives and Conclusion: Only studies of larger numbers of children, proposing relationships derived from allometric equations, will be able to provide real reference values.

Aerobic physical fitness, in children, is assessed by measurement of the maximal oxygen consumption during exercise testing. Representative norms of the studied population are required for interpretation. The aim of this article is to specify and review the available VO2max norms and factors of variation, including: sex, anthropometric characteristics (height, lean body mass and weight) and physical activity level. Ideally, VO2max norms should include lean body mass and physical activity with an allometric equation. Since such norms do not exist today, interpretation remains difficult. In France, the must satisfactory norms for non trained children include body mass without an allometric equation (boys: 47 +/- 2 ml.mn.-1 kg-1, girls: 40 +/- 3 ml.mn.-1 kg-1 with a post puberty decrease). Further studies on VO2max norms that include lean body mass and a physical activity questionnaire are required to improve exercise test interpretation in children.

The aim of the study was to define the changes of parameters of breathing pattern and ventilation (VE) as a function of age during maximal exercise in children. A multi-longitudinal survey was conducted in forty four untrained schoolboys, divided in three groups with initial age of 11.2 years for group I, 12.9 years for group II, and 14.9 for group III. These children were subsequently followed three years ago at the same period. The range age was thus 11.2 to 16.9 years. This study showed that, during growth, ventilation (VE max), tidal volume (VT max) and mean inspiratory flow (VT/TI max) increased significantly with age, that inspiratory frequency (f max) decreased, that inspiratory, expiratory and total time of the respiratory cycle (TI max, TE max, TTOT max) increased slightly and that the inspiration fraction (TI/TTOT max) was identical at 11 and 17 years. Furthermore we observed that the peak height velocity and peak tidal volume velocity took place at the same age, i.e., 14 years and that those of weight and VT/TI at the same age of 15 years. In conclusion, this study allowed us to define reference values for breathing pattern at maximal exercise in sedentary boys and to specify the relation between growth and parameters of breathing pattern in these children.