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M Roelants

Publications and source records attributed to M Roelants.

11 recordsLinked to original sources
PubMed2005

Effects of whole body vibration training on muscle strength and sprint performance in sprint-trained athletes.

Despite the expanding use of Whole Body Vibration training among athletes, it is not known whether adding Whole Body Vibration training to the conventional training of sprint-trained athletes will improve speed-strength performance. Twenty experienced sprint-trained athletes (13 male symbol, 7 female symbol, 17-30 years old) were randomly assigned to a Whole Body Vibration group (n=10: 6 male symbol and 4 female symbol) or a Control group (n=10: 7 male symbol, 3 female symbol). During a 5-week experimental period all subjects continued their conventional training program, but the subjects of the Whole Body Vibration group additionally performed three times weekly a Whole Body Vibration training prior to their conventional training program. The Whole Body Vibration program consisted of unloaded static and dynamic leg exercises on a vibration platform (35-40 Hz, 1.7-2.5 mm, Power Plate). Pre and post isometric and dynamic (100 degrees/s) knee-extensor and -flexor strength and knee-extension velocity at fixed resistances were measured by means of a motor-driven dynamometer (Rev 9000, Technogym). Vertical jump performance was measured by means of a contact mat. Force-time characteristics of the start action were assessed using a load cell mounted on each starting block. Sprint running velocity was recorded by means of a laser system. Isometric and dynamic knee-extensor and knee-flexor strength were unaffected (p>0.05) in the Whole Body Vibration group and the Control group. As well, knee-extension velocity remained unchanged (p>0.05). The duration of the start action, the resulting start velocity, start acceleration, and sprint running velocity did not change (>0.05) in either group. In conclusion, this specific Whole Body Vibration protocol of 5 weeks had no surplus value upon the conventional training program to improve speed-strength performance in sprint-trained athletes.

Adaptation, Physiological↗
PubMed2004

CUGE: a screening instrument for alcohol abuse and dependence in students.

OBJECTIVES: The prevalence of alcohol abuse on college campuses ranges from 7 to 17%. Frequent heavy drinkers place themselves and others at risk for a variety of adverse consequences and frequently remain undetected. Brief individual interventions result in a significant reduction on the number of drinks. Therefore, detection of students at risk is useful and desirable. The CUGE has been elsewhere described as a promising screening device for problem drinking in students. In order to determine the diagnostic value of this new questionnaire, we set up a validation study in a new and independent population of freshmen. METHODS: A cross-sectional diagnostic study. Participants were college freshmen of the Katholieke Universiteit Leuven. All students received a questionnaire, containing the CUGE, being the test of interest, and the CIDI as the reference test. RESULTS: The CUGE combines a very high sensitivity of 91% with a reasonable specificity of 76.3% in this validation group. CONCLUSIONS: The CUGE is an excellent screening device in this population of students. In addition, it is a short questionnaire with only yes or no questions. This makes the CUGE easily applicable as a part of broad routine questionnaires.

Adult↗
PubMed2004

Effects of 24 weeks of whole body vibration training on body composition and muscle strength in untrained females.

The aim of this study was to investigate and to compare the effect of 24 weeks "whole body vibration" training and fitness training on body composition and on muscle strength. Forty-eight untrained females (21.3 +/- 2.0 yr) participated in the study. The whole body vibration group (N = 18) performed unloaded static and dynamic exercises on a vibration platform (35 - 40 Hz, 2.5 - 5.0 mm; Power Plate). The fitness group (N = 18) followed a standard cardiovascular (15 - 40 min) and resistance training program including dynamic leg press and leg extension exercises (20 - 8 RM). Both groups trained 3 times weekly. The control group (N = 12) did not participate in any training. Body composition was determined by means of underwater weighing. Additionally 12 skinfolds were assessed. Isometric (0 degrees /s) and isokinetic (50 degrees /s, 100 degrees /s, 150 degrees /s) knee-extensor strength was measured by means of a motor-driven dynamometer (Technogym). Over 24 weeks there were no significant changes (p > 0.05) in weight, in percentage body fat, nor in skinfold thickness in any of the groups. Fat free mass increased significantly in the whole body vibration group (+ 2.2 %) only. A significant strength gain was recorded in the whole body vibration group (24.4 +/- 5.1 %; 5.9 +/- 2.1 %; 8.3 +/- 4.4 %; 7.6 +/- 1.5 %) and in the fitness group (16.5 +/- 1.7 %; 12.0 +/- 2.7 %; 10.4 +/- 2.3 %; 10.2 +/- 1.9 %), at 0 degrees /s, 50 degrees /s, 100 degrees /s and 150 degrees /s respectively. In conclusion, 24 weeks whole body vibration training did not reduce weight, total body fat or subcutaneous fat in previously untrained females. However, whole body vibration training induces a gain in knee-extensor strength combined with a small increase in fat free mass. The gain in strength is comparable to the strength increase following a standard fitness training program consisting of cardiovascular and resistance training.

Adult↗
PubMed2000

The value of CAGE, CUGE, and AUDIT in screening for alcohol abuse and dependence among college freshmen.

BACKGROUND: This study attempted to (1) determine the prevalence of alcohol problems in college freshmen, (2) assess the performance of both the CAGE and the Alcohol Use Disorders Identification Test (AUDIT) questionnaires in this population, and (3) assess the possibility of improving the CAGE and/or AUDIT. METHODS: A sample of 3564 consecutive college freshmen, with a mean age of 18 years, at the Catholic University of Leuven, (Belgium) completed, during a cross-sectional study, a questionnaire assessing drinking behavior and identifying students at risk as defined by DSM-IV criteria. The questionnaire also included the CAGE questionnaire and the AUDIT. Calculations of sensitivity, specificity, negative predictive value, positive predictive value, likelihood ratios, and receiver operating characteristic curves for different scores of the CAGE and the AUDIT were performed, using DSM-IV criteria as the reference standard. RESULTS: The area under the receiver operating characteristic curve of the CAGE and the AUDIT was 0.76 and 0.85, respectively. The cutoff score of 1 for the CAGE was associated with a sensitivity of 42%, a specificity of 87%, a positive predictive value of 36%, and a negative predictive value of 90%. A score of 6 or more for the AUDIT gave a sensitivity of 80%, a specificity of 78%, a positive predictive value of 37%, and a negative predictive value of 77%. These results were related with a prevalence of 14.1% of alcohol problems. Replacing one question of the CAGE by "often driving under the influence" resulted in the CUGE (acronym for "cut down, under influence, guilty feelings, and eye opener"), with an area under the curve of 0.96, a positive likelihood ratio of 8.7, and a negative likelihood ratio of 0.04. CONCLUSIONS: Prevalence of alcohol problems in college students is confirmed to be high. When screening for alcohol problems in a college freshmen population, one question seems extremely important. The newly constructed CUGE questionnaire may improve screening efforts in students, compared with existing questionnaires.

Adolescent↗
PubMed1999

[Prevalence of alcohol abuse and alcohol dependence according to DSM-IV criteria in first year university students].

OBJECTIVE: To determine the prevalence of alcohol problems in first-year college students. DESIGN: Cross-sectional. METHOD: Data on the prevalence of alcohol abuse or dependence according to DSM-IV criteria were collected in the period November 1995-April 1996 among college freshmen at the Catholic University of Louvain (Belgium). 3564 consecutive students completed a questionnaire which assessed drinking behaviour (Composite International Diagnostic Interview CIDI, Section J) and identified students at risk as defined by DSM-IV criteria. Our study included a large number of college freshmen, so we were able to perform our analyses with a large statistical power. All students had the opportunity to refuse their co-operation, but there were no non-responders, so selection bias was absent. The medical ethical committee of the KU Leuven approved this study. RESULTS: Of all 3564 consecutive students 501 (14.1%; 95% confidence interval (95% CI): 12.9-15.3) met DSM-IV criteria of alcohol abuse (n = 373; 10.5%; 9.5-11.5) or of alcohol dependence (n = 128; 3.6%; 3.0-4.2). Of the male students 301 (18.5%; 16.7-20.5) met the criteria of alcohol abuse and 96 (5.9%; 4.8-7.1) of alcohol dependence, of the female students 72 (3.7%; 2.9-4.6) and 32 (1.6%; 1.2-2.3) respectively. More than 10% (12.2%; 11.1-13.3) of these freshmen operated a vehicle under influence. This contributed in a major way to the DSM-IV conclusion. CONCLUSION: In this, one of the first studies among college freshmen using DSM-IV criteria the prevalence of alcohol abuse was in excess of 10%. In addition a substantial proportion of college freshman appeared to be alcohol dependent according to DSM-IV criteria.

Adolescent↗
PubMed1999

The effect of reconstitution of an Haemophilus influenzae type b-tentanus toxoid conjugate (PRP-T) vaccine on the immune responses to a diphtheria-tetanus-whole cell pertussis (DTwP) vaccine: a five-year follow-up.

Controversial results have been obtained from previous studies on the combined administration of Haemophilus influenzae type b-tetanus toxoid conjugate (PRP-T) and diphtheria-tetanus-whole-cell pertussis (DTwP) combination vaccines, with regard to possible reciprocal interference between the constituent antigens. To document the priming effect and possible long-term immunogenic interference of PRP-T and DTwP combination vaccines, a randomized, double-blind, controlled study was conducted in Belgium. A total of 168 healthy infants received, at 3, 4 and 5 months of age, DTwP vaccine mixed just prior to injection either with PRP-T vaccine (group A, DTwP//PRP-T, N = 85) or with placebo (group B, DTwP//Placebo, N = 83). At the age of 14 months, children of both groups were randomized to receive either a dose of DTwP//PRP-T vaccine (subgroups A1 and B1) or a dose of Hib polysaccharide (PRP) vaccine (subgroups A2 and B2). Those children in subgroups A1 and B1 had an additional serum sample taken at the age of 5 years (at the time of a DT booster). The immune response to Hib polysaccharide at the age of 4, 5 and 6 months confirmed the excellent immunogenicity profile of PRP-T in infants. In addition, the vigorous anamnestic response (i.e. a 20-fold increase of GMT) to a booster dose of the plain capsular polysaccharide (PRP) reflected the efficient Hib-priming induced by the combined DTwP//PRP-T vaccine. Reconstitution of PRP-T with DTwP did not affect the immune response to diphtheria toxoid or pertussis agglutinins. Nevertheless, at almost any time point during the five-year follow-up, the tetanus antitoxin GMT values were significantly lower in the DTwP//PRP-T group (A and A1) than in the DTwP//Placebo group (B and B1). Despite the suppressive effect on GMT values, intergroup differences in rates of seroprotection were never significant, except after doses 2 and 3 for which there were lower percentages of children in group A with antitoxin titers > 0.05 IU/mL and > 1.0 IU/mL. In the group primed with the combined DTwP//PRP-T vaccine, (1) a DT booster dose at the age of 5 years provoked a 150-fold increase in tetanus antitoxin GMT, (2) a high tetanus antitoxin GMT value was attained (GMT = 19.3 IU/mL) and (3) all children in this group had tetanus antitoxin titers > 1.0 IU/mL, so it may be concluded that all these children will still be protected against tetanus until at least the age of the next recommended booster dose (i.e. the age of 15 years). No differences in the occurrence of adverse events were observed between the groups who received the DTwP//PRP-T vaccine or the DTwP//Placebo vaccine, both vaccines being associated with events customarily attributable to DTwP (data not shown). Our results indicate (1) that the combination vaccine, DTwP//PRP-T, represents a safe and effective alternative for the existing uncombined vaccines and (2) that the long-term effect of interference between the components of future combination vaccines should be studied with subsequent booster doses, followed by the evaluation of persistence of antibodies over several years.

Agglutination Tests↗
PubMed1999

Priming effect, immunogenicity and safety of an Haemophilus influenzae type b-tetanus toxoid conjugate (PRP-T) and diphtheria-tetanus-acellular pertussis (DTaP) combination vaccine administered to infants in Belgium and Turkey.

To evaluate the priming effect, immunogenicity and safety of an Haemophilus influenzae type b (Hib) tetanus toxoid conjugate (PRP-T) and diphtheria-tetanus-acellular (two component) pertussis (DTaP) combination vaccine, a randomized, comparative study was conducted in two centers, one in Belgium and one in Turkey. A total of 410 healthy infants, 160 in Belgium and 250 in Turkey, randomly received DTaP and PRP-T vaccines in one of three fashions. One group (N = 138) received DTaP and PRP-T vaccines reconstituted immediately prior to injection at 3, 4 and 5 months of age, and are referred to as the combined, short schedule group (Co-S). A second group (N = 135) received DTaP + PRP-T simultaneously but injected at different sites according to the same schedule, and are referred to as the associated, short schedule group (As-S). The third group (N = 137) also received DTaP + PRP-T at separate sites, but at 2, 4 and 6 months, and are referred to as the associated, long schedule group (As-L). The As-L group allowed for serological bridging with a Senegalese two-component pertussis vaccine efficacy trial, using the same batch of DTaP vaccine. Children of both short-schedule groups (Co-S and As-S) received, at the age of 12-14 months, a booster dose of DTaP vaccine associated with unconjugated PRP vaccine. Mixing of the vaccines did not affect the immune response to the antigens included in the DTaP vaccine. The immune response to Hib capsular polysaccharide, however, was significantly lower after combined administration (Co-S group) than after associated (As-S group) administration (P < 0.0001), with a similar trend among both countries (GMTs, 1.78 microg/ml and 6.19 microg/ml in Belgium, and 5.02 microg/ml and 11.67 microg/ml in Turkey). Booster vaccination with the unconjugated PRP induced a vigorous and similar anamnestic response in both groups. Belgian infants showed a significantly lower immune response to all antigens than Turkish infants (P < or = 0.001 for all antigens), with a similar trend among each study group. In all groups, the incidence of adverse events was lower than that usually reported after DTwP(whole-cell) vaccine. Higher rates of systemic reactions were observed in the Belgian population, possibly due to differences in reporting practice. Our results indicate (1) that the combination vaccine, DTaP//PRP-T, represents an important improvement over the existing uncombined vaccines; (2) that immunogenicity studies should include at least one booster injection to evaluate priming effects by combined vaccines; and (3) that it is feasible and valuable to co-randomize combination vaccine studies in sufficiently different geographical areas and child populations.

Belgium↗