Methodological issues associated with longitudinal research: findings from the Leuven Longitudinal Study on Lifestyle, Fitness and Health (1969 - 2004)

Longitudinal studies provide unique opportunities but are also faced with several limitations. The purpose of this study was to document three of these issues ("imperfect" design, evolution of data collection methods, representativeness) by means of the Leuven Longitudinal Study on Lifestyle, Fitness and Health (LLSLFH). The LLSLFH (1969 - 2004) comprises observations on males between 12 and 18 years and at 30, 35, 40, and 47 years, and on females at 16 and 40 years. In the most recent phase of the study, spouses and offspring were also included. The different phases and evolving research questions throughout the LLSLFH required an appropriate adaptation of the research design. The associated evolution of data collection methods largely reflects the changing ideas about physical fitness, body composition, and physical activity, the continuing search for new and better measurement techniques, and the need for adaptations with age. Ongoing study participants are representative in terms of body composition and, except for adolescence in males, also physical activity. No straightforward answer can be given concerning physical fitness. In both sexes, socio-economic status is above average. When informed about the possible "pitfalls" of longitudinal research in advance, several measures could be taken to prevent or limit them as much as possible.     

Prediction of adult height in girls: The Beunen-Malina-Freitas method

Abstract

The purpose of this study was to validate and cross-validate the Beunen-Malina-Freitas method for non-invasive prediction of adult height in girls. A sample of 420 girls aged 10–15 years from the Madeira Growth Study were measured at yearly intervals and then 8 years later. Anthropometric dimensions (lengths, breadths, circumferences, and skinfolds) were measured; skeletal age was assessed using the Tanner-Whitehouse 3 method and menarcheal status (present or absent) was recorded. Adult height was measured and predicted using stepwise, forward, and maximum R ² regression techniques. Multiple correlations, mean differences, standard errors of prediction, and error boundaries were calculated. A sample of the Leuven Longitudinal Twin Study was used to cross-validate the regressions. Age-specific coefficients of determination (R ²) between predicted and measured adult height varied between 0.57 and 0.96, while standard errors of prediction varied between 1.1 and 3.9 cm. The cross-validation confirmed the validity of the Beunen-Malina-Freitas method in girls aged 12–15 years, but at lower ages the cross-validation was less consistent. We conclude that the Beunen-Malina-Freitas method is valid for the prediction of adult height in girls aged 12–15 years. It is applicable to European populations or populations of European ancestry.     

Digit ratio (2D:4D) and competition level in world-class female gymnasts

Abstract

In this study the relationship between the digit ratio (2D:4D) and artistic gymnastics performance and competition level was investigated in a sample of Caucasian world-class female gymnasts (n = 145). The sample was divided into three competition events (compulsories, free work, final score). Within each event three performance groups (lowest, middle, and highest) were based on the competition scores gathered at the World Championships at Rotterdam, the Netherlands, in 1987. Lengths of the digits were measured on X-rays of the left hand. Several anthropometric dimensions were measured and from those measurements an androgyny index (Bayer & Bayley) and somatotype components (endomorphy, mesomorphy, ectomorphy) were calculated. Although significant differences in some anthropometric characteristics between the performance level groups within each competition event were observed, no significant differences in the 2D:4D ratios were found between the performance level groups, varying from 0.918 ± 0.020 to 0.924 ± 0.020. Also, no significant correlations were observed between the 2D:4D ratio and anthropometric, androgyny, and somatotype characteristics, r varying from r = –0.11 to r = +0.12. It can be concluded that in this sample the 2D:4D digit ratio, unlike other anthropometric characteristics, is not a discriminating factor for the performance in artistic gymnastics performance on a world-class level.     

Vergleichsarbeiten in Baden-Württemberg

Standard comparative tests are meant to provide a reference system within the framework of educational reforms for development of school lessons. Compulsory comparative testing was introduced in Baden-Württemberg at the end of the school year 2005/2006. The teachers carried out the tests and corrected them themselves. Afterwards they received feedback at school and class levels, which was based on a prior statewide pilot study. The repeated survey had the aim of investigating which intended effects (reference attainment for orientation) and non-intended effects (narrowing-the-curriculum, pre-testing and exercises) teachers associated with this new instrument. Teachers of technical secondary schools (Realschulen) in Baden-Württemberg were surveyed. In the survey before the introduction of standard comparative testing (2004; n _{t 1}?=?914), teachers expected both intended and non-intended effects. Four years after their introduction (2009; n _{t 1}?=?734), respondents were asked to estimate the effects of standard comparative tests. The effects??in every dimension??were judged to be significantly less than had been expected before their introduction. It is pleasing that the teachers did not judge the anticipated narrowing-the-curriculum effects to be significant. However, they also did not see the instrument as a noteworthy orientation help for planning and assessing lessons. Standard comparative tests were not seen by the respondents to provide a reference for new lesson developments.