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Biomedical subjects

J Lefevre

Publications and source records attributed to J Lefevre.

At least 19 recordsLinked to original sources
PubMed2006

Validity of a physical activity computer questionnaire in 12- to 18-year-old boys and girls.

The reliability and validity of a physical activity computer questionnaire of a usual week were studied in 33 adolescents between 12 and 18 years of age. Intraclass correlation coefficients and Kappa values were calculated to verify test-retest reliability. Validity was investigated by calculating Pearson correlation coefficients between the questionnaire and the Computer Science and Applications uniaxial accelerometer (CSA). Accelerometer data were obtained during seven successive days (sum and mean counts, estimated MET). Intraclass coefficients generally exceeded 0.70 and all Kappa values but one varied between 0.44 and 1.00. Transport variables (active transport from and to school, and during leisure time) showed no relationship with CSA. Sport participation during leisure time, sport participation summed with total transport, and the frequencies of moderate and hard activity were significantly correlated with CSA (r between 0.48 and 0.78). These data indicate that the physical activity computer variables provide reliable information. Moreover, sport participation (and summed with total transport) and the frequencies of moderate and hard activity provide valid data about adolescents' usual week physical activity, based on CSA comparison.

Adolescent↗
PubMed2002

Relation between cardiovascular risk factors at adult age, and physical activity during youth and adulthood: the Leuven Longitudinal Study on Lifestyle, Fitness and Health.

This study investigated the relationship between sports participation/physical activity during youth (13 - 18 years of age) and adulthood (30 - 40 years of age), and cardiovascular risk factors (body fat and fat distribution, blood pressure, lipoprotein levels and cardiorespiratory fitness) at 40 years of age. Subjects were 166 Flemish males from "The Leuven Longitudinal Study on Lifestyle, Fitness and Health". Physical activity was assessed by means of a sports participation inventory and the Tecumseh community Health Study Questionnaire. In addition to correlation and multiple stepwise regression analyses, different groups (at risk, not at risk) were contrasted on sports participation/physical activity parameters using ANOVA. Long-term exposure during adulthood to daily physical activity was slightly related to a low/high risk profile for waist circumference, percent body fatness, triglycerides and peak VO(2). Sports participation during adolescence was not related to levels of cardiovascular risk factors at 40 years of age.

Adolescent↗
PubMed2001

Trends in BMI among Belgian children, adolescents and adults from 1969 to 1996.

OBJECTIVE: To document secular data on changes in the distribution of body mass index (BMI), to determine the probability of overweight at 40 y of age in Belgian males in relation to the presence or absence of overweight at different ages in adolescence, and to estimate tracking of BMI in Belgian males in Belgium aged 12-40 y. DESIGN: Cross-sectional and mixed longitudinal surveys in nationally representative samples of Belgian males and females. SUBJECTS: Cross-sectional-more than 21 000 boys and 9698 girls; to examine secular trends-3164 boys and 5140 girls; to examine tracking-161 males. MEASURES: Body mass and height to determine BMI. RESULTS: In Belgian children the degree of overweight has increased between 1969 and 1993. Tracking of BMI is high in adolescence (r=0.77) and adulthood (r=0.69-0.91) and moderate from adolescence to adulthood (r=0.49). In Belgian males, the probability of overweight at 40 y of age in the presence of overweight at different ages in adolescence is important (odds ratios 5.0-6.9). CONCLUSIONS: Cross-sectional and longitudinal data, trends and tracking of BMI from 1969 until 1996 in Belgium indicate an increase in the degree of childhood overweight and obesity. Moreover, the risk of an overweight male adolescent becoming an overweight adult is substantial. Measures to restrict the Belgian overweight and obesity epidemic should be taken.

Adolescent↗
PubMed2001

Comparison of two questionnaires with a tri-axial accelerometer to assess physical activity patterns.

Two physical activity questionnaires were evaluated against cardiorespiratory fitness (VO2 peak), and a tri-axial accelerometer for movement registration (Tracmor) in 166 men, aged 40 years, within the framework of the Leuven Longitudinal Study on Lifestyle, Fitness, and Health. Tracmor data were obtained during four successive days. Besides the work index, the sport index, and the total activity index from the Baecke questionnaire, the subjective activity score, calculated energy expenditure during work, work index, and the total activity index from the Tecumseh Community questionnaire showed significant correlation coefficients with the mean Tracmor output (r = 0.26-0.47, p < 0.01). The questionnaire submeasures and the Tracmor output as generated in the same physical activity dimension showed the same relationships (r = 0.22-0.50, p < 0.01). Multiple stepwise regression and stepwise discriminant analyses showed the Baecke questionnaire as the best indicator of the subject's physical activity level. Extra information about the physical activity level was given by two Tecumseh submeasures, e.g. energy expenditure during work and sleeping time. The results indicated that the Baecke questionnaire is superior in large-scale studies because of simplicity. However, the Tecumseh questionnaire can give detailed information about physical activity patterns and energy expenditure.

Activities of Daily Living↗
PubMed2001

Anthropometric characteristics of elite female junior rowers.

During the 1997 Federation Internationale des Sociétés d'Aviron (FISA) World Junior Rowing Championships, the anthropometric characteristics of 245 female junior rowers aged 17.5 +/- 0.8 years (mean +/- s) were assessed. Twenty-seven body dimensions (body mass, 6 heights or lengths, 4 breadths, 10 girths and 6 skinfolds) were measured in total. The elite female junior rowers were taller (174.5 +/- 6.2 cm) and heavier (69.5 +/- 6.2 kg), with greater length, breadth and girth dimensions, but lower skinfold thicknesses than a representative sample of Flemish (Belgian) girls of the same chronological age. An anthropometric profile chart was constructed that was rowing-specific and norms were established. Compared with scullers, sweep rowers were heavier (+4.2 kg) and taller (+2.8 cm), with greater length, breadth (except for femur width) and girth dimensions (except for calf girth). Sweep rowers also had greater skinfold thicknesses (except for the thigh and calf skinfolds). Finalists were heavier (+3.6 kg) and taller (+3.9 cm), with greater length, breadth (except for femur width) and girth dimensions (except for calf girth) than non-finalists. No significant differences were found for skinfold thicknesses between finalists and non-finalists.

Adolescent↗
PubMed2001

Tracking of physical fitness during adolescence: a panel study in boys.

PURPOSE: To investigate the tracking in physical fitness (PF) viewed as a whole, a multidimensional trait of the subject, and to establish the stability of each factor of PF in adolescence from the perspective of a panel study using the structural equation modeling approach. METHODS: From a sample of 454 boys followed from 12 to 18 yr of age of the Leuven Growth Study, we considered only three consecutive measurement occasions with a mean age of 12.76, 14.69, and 17.73 yr. Physical fitness was evaluated by means of a battery composed of the following tests: plate tapping, sit and reach, vertical jump, arm pull, leg lifts, bent arm hang, and shuttle run. Structural equation models were fitted to the data, namely autoregressive models with latent variables. These models were used to quantify the tracking of PF as a whole and also of the individual marker variables of fitness. RESULTS: Stability estimates of PF as a whole are rather high, beta21 = 0.86 and beta32 = 0.68, with an explained variance of 74% and 73%, respectively. Tracking coefficients represented by disattenuated autocorrelations among the fitness factor gave high results: r1,2 = 0.86; r1,3 = 0.78; and r2,3 = 0.85. CONCLUSIONS: Physical fitness as a whole is highly stable in adolescent years and very predictable from early years. The same is observed for each factor of fitness. Moreover, autoregressive models within the context of structural equation modeling are better suited than simple Pearson or Spearman autocorrelations to study the tracking problem of PF.

Adolescent↗
PubMed2001

Bone mass and lifetime physical activity in Flemish males: a 27-year follow-up study.

PURPOSE: The present population study is conducted to examine the extent to which lifetime physical activity and lifestyle parameters contribute to bone mass. METHODS: The design of the project is a 27-yr prospective follow-up study. Subjects are 126 males gathered from the Leuven Longitudinal Study on Lifestyle, Physical Fitness and Health, and aged 13 yr at the onset of the study and 40 at the end of the follow-up. Physical activity and lifestyle parameters are obtained with questionnaires. Bone mass is measured by means of dual-energy x-ray absorptiometry (DXA). RESULTS: Results from correlation and regression analyses show that the body mass index (BMI) is the most important parameter in relation to cortical and trabecular bone mass at every examination period. Longitudinally, static arm strength, running speed, and upper muscular endurance contribute significantly to the prediction of adult bone mass. The parameter "change in motor fitness" between 18 and 13 yr old was used to control for hereditary influences. The score for static arm strength and trunk muscle strength demonstrates a significant correlation with adult total bone mineral content (BMC) and lumbar bone mineral density (BMD), respectively. At the age of 40, the Baecke sports index is almost equally important as BMI in explaining the variance in BMD, and static arm strength is the most important parameter (after BMI) for BMC. CONCLUSION: Lifetime physical activity, physical fitness, and BMI all contribute to adult bone mass. The clinical relevance of these findings is emphasized by the fact that the observed patterns of physical activity and motor fitness pertain to customary lifestyle and are thus feasible targets.

Adolescent↗
PubMed2000

Evaluation of the influence of cardiorespiratory fitness on diverse health risk factors, independent of waist circumference, in 40-year-old Flemish males.

OBJECTIVE: To examine whether cardiorespiratory fitness is associated with health risk factors, independent of abdominal obesity (waist circumference). RESEARCH METHODS AND PROCEDURES: Data from 141 40-year-old Flemish male subjects were used in a cross-sectional design. The main outcome measure in this study was the health risk profile, composed of lipid parameters, blood pressure, and body composition parameters. Data were analyzed by regression analysis and by means of analysis of covariance with waist circumference (WC) as covariate and cardiorespiratory fitness as source of variance. RESULTS: The data demonstrated that cardiorespiratory fitness was significantly associated with triglycerides, with the ratio of total cholesterol/serum high density lipoprotein cholesterol, and with percent body fat, independent of an association with WC. DISCUSSION: Major findings of the present cross-sectional study indicate that a high WC is associated with adverse health-related lipid profile and body composition characteristics and that relatively high levels of aerobic fitness attenuate the health risk associated with a large WC.

Adipose Tissue↗
PubMed2000

Anthropometric characteristics of elite male junior rowers.

During the 1997 Federation Internationale des Sociétés d'Aviron World Junior Rowing Championships, anthropometric data on 383 male junior rowers were assessed. With 430 participating athletes, the sample represented 89% of the population. In addition to age, 27 dimensions were measured: body mass, six heights or lengths, four breadths, 10 girths, and six skinfolds. The elite male junior rowers were tall (187.4 (5.8) cm; mean (SD)) and heavy (82.2 (7.4) kg), with larger length, breadth, and girth dimensions than a nationally representative sample of Belgian boys of the same chronological age. A rowing specific anthropometric profile chart with norms was constructed. The stature of the junior rowers is similar to that of adult heavyweight elite rowers, except that the junior rowers are lighter. Compared with non-finalists, finalists are heavier (but still lighter than the adult heavyweight elite rower) and taller, with greater length, breadth (except for the bicristal diameter), and girth dimensions.

Adolescent↗
PubMed1999

Value and limitations of the Duke criteria for the diagnosis of infective endocarditis.

OBJECTIVES: The purpose of this study was to assess the value and limitations of Duke criteria for the diagnosis of infective endocarditis (IE). BACKGROUND: Duke criteria have been shown to be more sensitive in diagnosing IE than the von Reyn criteria, but the diagnosis of IE remains difficult in some patients. METHODS: Both classifications were applied in 93 consecutive patients with pathologically proven IE. Blood cultures, and transthoracic and transesophageal echocardiography were performed in all patients. RESULTS: Sensitivities for the diagnosis of IE were 56% and 76% for von Reyn and Duke criteria, respectively. Fifty-two patients were correctly classified as "probable IE" by von Reyn and "definite IE" by Duke criteria (group 1). However, discrepancies were observed in 41 patients. Eleven patients (group 2) were misclassified as "rejected" by von Reyn, but were "definite IE" by Duke criteria; this difference could be explained by negative blood cultures and positive echocardiogram in all patients. In eight patients (group 3), the diagnosis of IE was "possible" by von Reyn but "definite" by Duke criteria. This difference was essentially explained by the failure of the von Reyn classification to consider echocardiographic abnormalities as major criteria. Twenty-two patients (group 4) were misclassified as possible IE using Duke criteria, being false negative of this classification. Echocardiographic major criteria were present in 19 patients, but blood cultures were negative in 21 patients. The cause of negative blood cultures was prior antibiotic therapy in 11 patients and Q-fever endocarditis diagnosed by positive serology in three cases. CONCLUSIONS: Twenty-four percent of patients with proved IE remain misclassified as "possible IE" despite the use of Duke criteria, especially in cases of culture-negative and Q-fever IE. Increasing the diagnostic value of echographic criteria in patients with prior antibiotic therapy and typical echocardiographic findings and considering the serologic diagnosis of Q fever as a major criterion would further improve the clinical diagnosis of IE.

Bacteria↗
PubMed1999

Associations between physical activity, nutritional practices and health-related anthropometry in Flemish males: a 5-year follow-up study.

OBJECTIVE: To examine the extent to which extent health-related anthropometric characteristics such as body mass index, waist-hip ratio, waist girth, percentage of body fat and weight gain are associated with physical activity and nutritional habits in a prospective follow-up study. DESIGN: A 5-y prospective follow-up study. SUBJECTS: 132 healthy men from The Leuven Longitudinal Study on Lifestyle, Physical Fitness, and Health. MEASUREMENTS: The main outcome measures in this study were body mass index, waist-hip ratio, waist girth, percentage of body fat and significant weight gain at the ages of 35 and 40y. An unhealthy body composition was defined as a body mass index above 26, a waist-hip ratio above 0.95, a waist girth and body fat percentage above percentile 75 at the end of the 5-y follow-up period and a significant weight gain of 5 kg or more between the two examination periods. Anthropometric characteristics were derived from clinical examination. Physical activity at the age of 35 and 40 and nutritional habits at the age of 40 were determined from questionnaires. RESULTS: Physical activity was the most important predictor for the waist-hip ratio in this sample. In contrast, nutritional habits show a stronger relationship with body mass index. The absolute amount of energy intake is not as important as the dietary factors in predicting subjects with overweight or an unhealthy body composition. The index of occupational activities appears to be the most important physical activity variable. CONCLUSION: The relative contribution of physical activity and nutritional habits in health-related anthropometry varies with the characteristic considered. It is important to include all components of physical activity, and occupational activities in particular, in determining these relationships in a general population sample.

Adipose Tissue↗
PubMed1999

Doubly labelled water validation of three physical activity questionnaires.

This study investigated the validity of the Baecke Questionnaire, the Five City Project Questionnaire, and the Tecumseh Community Health Study Questionnaire in 19 Flemish males, using correlation and multiple stepwise regression analyses. The three questionnaires are commonly used physical activity questionnaires in epidemiological studies. The physical activity level (PAL) as measured with the doubly labelled water method was used as the criterion. The Baecke total activity index showed the highest correlation coefficient with PAL (r = 0.69, p < 0.001). Also the sweat index from the Five City Project Questionnaire, and total daily energy expenditure from the Tecumseh Community Health Study Questionnaire showed significant associations with PAL, respectively 0.57 (p < 0.05) and 0.64 (p < 0.01). Multiple stepwise regression analyses supported the findings from the correlation study. The largest individual contribution in PAL was from the activity index (45%) for the Baecke Questionnaire, the sweat index (29%) for the Five City Project Questionnaire, and total daily energy expenditure (38%) for the Tecumseh Community Health Study Questionnaire. In conclusion, the questionnaires, and certainly the Baecke Questionnaire, can provide valid data about physical activity. Therefore they are useful in epidemiological studies.

Adult↗
PubMed1999

Ulnar variance and skeletal maturity of radius and ulna in female gymnasts.

UNLABELLED: It is has been suggested that repetitive loading on the distal end of the radius in elite gymnasts may lead to epiphyseal changes, a premature closure (union) of the radius growth plate, and ulnar overgrowth. PURPOSE: It is hypothesized that ulnar overgrowth in female gymnasts is associated with advanced maturity status and early onset of epiphyseal closure of the radius, and later maturity status and later onset of epiphyseal closure of the ulnar. METHODS: Posterior-anterior radiographs of 201 female gymnasts, participants of the 1987 World Championships Artistic Gymnastics, were used to measure ulnar overgrowth, to determine skeletal maturation of the hand and wrist with the Tanner-Whitehouse technique, and to determine the maturity status of the radius and ulna separately, particularly with regard to the onset of epiphyseal closure. To test the hypothesis, extreme quintiles for ulnar overgrowth were contrasted for skeletal maturation of the hand and wrist and for maturity stages of the radius and ulna as defined by the Tanner-Whitehouse criteria. RESULTS: Female gymnasts who demonstrate ulnar overgrowth are skeletally more advanced in maturity status of the entire hand-wrist compared with gymnasts who did not show ulnar overgrowth. There were, however, no differences between gymnasts in the extreme quintiles of ulnar overgrowth in the maturation of the radius, although gymnasts with ulnar overgrowth show more advanced maturity status of the ulna. CONCLUSIONS: Ulnar overgrowth is thus not apparently associated with advanced maturity of the distal radial epiphysis as defined in protocols for assessing skeletal maturity and does not apparently lead to premature epiphyseal closure of the distal radius.

Adolescent↗
PubMed1999

The contribution of anthropometric characteristics to performance scores in elite female gymnasts.

BACKGROUND: Aims of this study were: a) to identify anthropometric variables correlated with gymnastic performance, and b) to predict performance scores from a combination of anthropometric dimensions. METHODS EXPERIMENTAL DESIGN: correlational analysis and a stepwise multiple regression were used. SETTING: Subjects were participants at the 24th World Championships Artistic Gymnastics, Rotterdam, The Netherlands, in 1987. PARTICIPANTS: A total of 168 female gymnasts (mean age: 16.5 +/- 1.8 years) were investigated. Each gymnast participated in all events. MEASURES: An extensive battery of anthropometric dimensions was taken on each athlete. The somatotype was estimated. Skeletal maturation of the hand-wrist was assessed. Competition scores for the four individual gymnastic events (balance beam, floor exercise, vault, uneven bars) and a composite score for each gymnast were the dependent variables. RESULTS: Moderately high, significant correlations (p < 0.01) were observed between skinfolds and endomorphy, and gymnastics performance scores, r varying from -0.38 to -0.60, for biceps skinfold and the score on balance beam, and for endomorphy and the total score, respectively. The correlations suggest that gymnasts with more subcutaneous fat and higher endomorphy have lower performance scores. About 32% to 45% of the variance in gymnastic performance scores could be explained by anthropometric dimensions and/or derived variables, but endomorphy and chronological age are the most important predictors. CONCLUSIONS: There is a relatively strong relationship between several anthropometric variables and gymnastic performance in a sample of elite female gymnasts, but the associations are not sufficiently high to predict performance scores on an individual basis.

Adolescent↗
PubMed1998

Reliability and validity of three physical activity questionnaires in Flemish males.

The reliability and validity of three physical activity questionnaires were studied using 90 Flemish males (30 aged 30 years, 30 aged 35 years, and 30 aged 40 years). Intraclass correlations (R) and kappa values were calculated to verify within judge and between judges reliability (objectivity) and test-retest reliability (stability) of the Tecumseh Community Health Study Questionnaire, the Five City Project Questionnaire, and the Baecke Questionnaire. Results showed high for within judge and between judges reliability. R coefficients for stability varied between 0.47 and 0.95. Kappa values varied between 0.20 and 0.73. Concurrent validity was investigated by comparing three levels of professional status. Workmen had higher indices concerning physical activity during work than clerks and managers. Congruent validity, studied by means of principal-components analysis, confirmed subdivision of habitual physical activity into three entities, physical activity during work, sports activities, and general leisure time. These results indicate that reliable and valid data can be obtained in Flemish males by three interviewer-assisted physical activity questionnaires.

Adult↗
PubMed1998

Evaluation of stroke performance in tennis.

In the present studies, the Leuven Tennis Performance Test (LTPT), a newly developed test procedure to measure stroke performance in match-like conditions in elite tennis players, was evaluated as to its value for research purposes. The LTPT is enacted on a regular tennis court. It consists of first and second services, and of returning balls projected by a machine to target zones indicated by a lighted sign. Neutral, defensive, and offensive tactical situations are elicited by appropriately programming the machine. Stroke quality is determined from simultaneous measurements of error rate, ball velocity, and precision of ball placement. A velocity/precision (VP) an a velocity/precision/error (VPE) index are also calculated. The validity and sensitivity of the LTPT were determined by verifying whether LTPT scores reflect minor differences in tennis ranking on the one hand and the effects of fatigue on the other hand. Compared with lower ranked players, higher ones made fewer errors (P < 0.05). In addition, stroke velocity was higher (P < 0.05), and lateral stroke precision, VP, and VPE scores were better (P < 0.05) in the latter. Furthermore, fatigue induced by a prolonged tennis load increased (P < 0.05) error rate and decreased (P < 0.05) stroke velocity and the VP and VPE indices. It is concluded that the LTPT is an accurate, reliable, and valid instrument for the evaluation of stroke quality in high-level tennis players.

Adult↗
PubMed1998

Morphological and performance characteristics as drop-out indicators in female gymnasts.

BACKGROUND: Aim of this study was to investigate if morphological and performance characteristics are significant indicators to predict drop-out in female gymnasts. METHODS EXPERIMENTAL DESIGN: comparative investigation between two groups of female gymnasts at the start of a 3-year follow-up period. SETTING: participants of the study came from two gymnastic clubs from the Antwerp region in Flanders, Belgium. PARTICIPANTS: in total, 81 female competitive gymnasts (mean age: 10.5 + 2.6 years) were investigated, of which 46 were continuing gymnasts, while 35 dropped-out from the sport during the following 3 years. MEASURES: included were a large battery of a anthropometric characteristics, skeletal maturation, physical fitness tests, and gymnastic-specific strength and flexibility tests. Differences between the two groups were analysed by means of the t-test and analysis of co-variance with chronological age as the co-variate. RESULTS: Compared to the gymnasts, the drop-outs were significant (p < 0.01) older (11.3 and 9.7 years respectively), more mature (skeletal ages are 10.6 and 9.4 years respectively), taller (143.5 cm and 135.2 cm respectively), and heavier (36.0 kg and 29.4 kg respectively). Also for almost all other anthropometric dimensions, gymnasts were significantly (p < 0.01) smaller than the drop-outs, except for the biceps, triceps, medial calf, and thigh skinfolds. Concerning the fitness and gymnastic-specific test characteristics, the drop-outs performed also significantly (p < 0.01) better than the continuing gymnasts. The ANCOVA-analysis, however, revealed that it was mainly the age factor that distinguished both groups. After controlling for chronological age, no differences between both groups could be demonstrated for almost all anthropometric and performance characteristics with the exception for upperarm circumference flexed, calf circumference, and biceps skinfold. For these variables, drop-outs showed still significant (p < 0.05) higher values compared to the gymnast's group. CONCLUSIONS: Based on these findings, it is concluded that factors related to the physical make-up and performance capacities of our gymnasts under study are minor indicators for the withdrawal from competitive gymnastics, and it is hypothesized that the social and psychological factors associated with the older age of the drop-out girls are presumably more important.

Adolescent↗