Biomedical subjects

Luc Léger

Publications and source records attributed to Luc Léger.

3 recordsLinked to original sources

PubMed2006

Worldwide variation in the performance of children and adolescents: an analysis of 109 studies of the 20-m shuttle run test in 37 countries.

This study is a meta-analysis of 109 reports of the performance of children and adolescents on the 20-m shuttle run test (20-mSRT). The studies were performed in 37 countries and included data on 418,026 children, tested between 1981 and 2003. Results were expressed as running speed (km x h(-1)) at the final completed stage of the 20-mSRT. Raw data were combined with pseudodata using Monte Carlo simulation. The 20-mSRT performances were expressed as z-scores relative to all children of the same age and sex from all countries. An overall "performance index" was derived for each country as the average of the age- and sex-specific z-scores for all children from that country. Factorial analysis of variance was used to compare scores among countries and regions, and between boys and girls of the same age. There was wide and significant (P < 0.0001) global variability in the performance of children. The best performing children were from the Northern European countries Estonia, Iceland, Lithuania, and Finland (0.6 - 0.9 standard deviations above the global average). The worst performing children were from Singapore, Brazil, USA, Italy, Portugal, and Greece (0.4 - 0.9 standard deviations below the global average). There is evidence that performance was negatively related to being overweight, as well as to a country's average temperature.

Adolescent↗

PubMed2004

Validity and reliability of the Huet questionnaire to assess maximal oxygen uptake.

The usual fitness tests available to assess maximal oxygen uptake (VO2max), a key fitness component, are not particularly useful for epidemiological studies. Questionnaires to assess VO2max, however, are simple, easy to use, and inexpensive. In 1986, Huet developed such a French general questionnaire, which now also has an English version. Its simplicity is interesting as it could be used to survey large populations. The purpose of this study was to assess the validity and reliability of this Huet questionnaire in a sample of healthy French volunteers. A total of 108 subjects were included in this study, 88 males and 20 females. The validity of the questionnaire was checked using correlation coefficients and a Bland-Altman plot between questionnaire estimations and measures of VO2max obtained with a stress test on a cycle ergometer. An intraclass correlation coefficient (ICC) was also calculated to determine the reliability of the questionnaire. Significant correlation was obtained with the Huet questionnaire and measured VO2max (r2 = 0.77, p = 0.0001, SEE = 5.97 ml x kg (-1 ) x min- (1), n = 108). The ICC showed very high reliability (ICC= 0.988, n = 21). The Huet questionnaire is an easy, rapidly administered tool that correlated highly with VO2 max in this sample population.

Adolescent↗

PubMed2002

Methods to determine aerobic endurance.

Physiological testing of elite athletes requires the correct identification and assessment of sports-specific underlying factors. It is now recognised that performance in long-distance events is determined by maximal oxygen uptake (V(2 max)), energy cost of exercise and the maximal fractional utilisation of V(2 max) in any realised performance or as a corollary a set percentage of V(2 max) that could be endured as long as possible. This later ability is defined as endurance, and more precisely aerobic endurance, since V(2 max) sets the upper limit of aerobic pathway. It should be distinguished from endurance ability or endurance performance, which are synonymous with performance in long-distance events. The present review examines methods available in the literature to assess aerobic endurance. They are numerous and can be classified into two categories, namely direct and indirect methods. Direct methods bring together all indices that allow either a complete or a partial representation of the power-duration relationship, while indirect methods revolve around the determination of the so-called anaerobic threshold (AT). With regard to direct methods, performance in a series of tests provides a more complete and presumably more valid description of the power-duration relationship than performance in a single test, even if both approaches are well correlated with each other. However, the question remains open to determine which systems model should be employed among the several available in the literature, and how to use them in the prescription of training intensities. As for indirect methods, there is quantitative accumulation of data supporting the utilisation of the AT to assess aerobic endurance and to prescribe training intensities. However, it appears that: there is no unique intensity corresponding to the AT, since criteria available in the literature provide inconsistent results; and the non-invasive determination of the AT using ventilatory and heart rate data instead of blood lactate concentration ([La(-)](b)) is not valid. Added to the fact that the AT may not represent the optimal training intensity for elite athletes, it raises doubt on the usefulness of this theory without questioning, however, the usefulness of the whole [La(-)](b)-power curve to assess aerobic endurance and predict performance in long-distance events.

Exercise↗