Search Results

You are looking at 1 - 10 of 825 items for :

  • "biological" x
Clear All
Restricted access

Jahan Heidari, Jürgen Beckmann, Maurizio Bertollo, Michel Brink, K. Wolfgang Kallus, Claudio Robazza and Michael Kellmann

training and competition loads, particularly in disciplines with intense competition schedules. Differences in biological (eg, heart rate [HR] variability), psychological (eg,motivation), as well as behavioral (eg, global positioning system [GPS]) parameters within and between athletes can be identified

Restricted access

Roy J. Shephard

A quantitative hypothetico-deductive approach has continued to contribute greatly to advances in biological and medical science. Quantitative methods are adopted over other approaches primarily because they contribute the most new knowledge about biological processes. Nevertheless, investigators make many assumptions when testing a biological hypothesis quantitatively. These assumptions may become invalid unless experiments are designed with great care. Problems arise in relation to formulating appropriate hypotheses, using volunteer samples, controlling the experimental intervention and potentially interfering behaviors, reaching an acceptable level of proof, excluding alternative hypotheses, and generalizing findings beyond the immediate experimental sample. When biologists are aware of these issues, they can take appropriate countermeasures and reach valid conclusions. However, the issues become more critical and resolution is less clear-cut when the same methods are extended from biology to psychology and the social sciences, and from general to special populations. In such situations, case studies and single-subject designs may have continuing relevance.

Restricted access

Thomas W. Rowland

A growing body of evidence implicates the existence of a functional subconscious governor in the brain, which controls level of habitual physical activity. Such a biologic control, acting in a classic feedback loop mechanism, might serve to contribute to the defense of energy balance. Many questions remain unanswered regarding the pliability of biologic control of activity and the extent that it might dictate daily energy expenditure. A consideration of this concept bears importance for those seeking an understanding of the mechanisms, prevention, and treatment of obesity as well as the link between exercise and health in the general population.

Open access

Sergei Iljukov, Jukka-Pekka Kauppi, Arja L.T. Uusitalo, Juha E. Peltonen and Yorck O. Schumacher

new anti-doping strategies, as the primary aim of doping is an improvement in athletic performance, which seems to be plateauing in many disciplines. 8 , 9 One of the recent anti-doping strategies is the implementation of the Athlete Biological Passport (ABP). 10 The ABP is based on a collection of

Restricted access

Brian D. Seiler, Eva V. Monsma and Roger D. Newman-Norlund

This study extended motor imagery theories by establishing specificity and verification of expected brain activation patterns during imagery. Eighteen female participants screened with the Movement Imagery Questionnaire-3 (MIQ-3) as having good imagery abilities were scanned to determine the neural networks active during an arm rotation task. Four experimental conditions (i.e., KINESTHETIC, INTERNAL Perspective, EXTERNAL Perspective, and REST) were randomly presented (counterbalanced for condition) during three brain scans. Behaviorally, moderate interscale correlations were found between the MIQ-3 and Vividness of Movement Imagery Questionnaire-2, indicating relatedness between the questionnaires. Partially confirming our hypotheses, common and distinct brain activity provides initial biological validation for imagery abilities delineated in the MIQ-3: kinesthetic imagery activated motor-related areas, internal visual imagery activated inferior parietal lobule, and external visual imagery activated temporal, but no occipital areas. Lastly, inconsistent neuroanatomical intraindividual differences per condition were found. These findings relative to recent biological evidence of imagery abilities are highlighted.

Restricted access

Grant M. Tinsley and Brett S. Nickerson

When estimating body composition, a pervasive recommendation is to perform assessments after a period of rest and fasting. This recommendation seeks to minimize biological error induced by daily activities, such as food and fluid ingestion or exercise. Overnight fasts are implemented for a variety

Restricted access

Lauren B. Sherar, Sean P. Cumming, Joey C. Eisenmann, Adam D.G. Baxter-Jones and Robert M. Malina

The decline in physical activity (PA) across adolescence is well established but influence of biological maturity on the process has been largely overlooked. This paper reviews the limited number of studies which examine the relationship between timing of biological maturity and PA. Results are generally inconsistent among studies. Other health-related behaviors are also considered in an effort to highlight the complexity of relationships between biological maturation and behavior and to provide future research directions.

Restricted access

Jorge Mota, José Carlos Ribeiro, Henrique Barros, Jos W.R. Twisk, José Oliveira and José A. Duarte

Background:

The purpose of the study was to investigate the longitudinal relationship between physical activity and clustering of some cardiovascular disease (CVD) risk factors after 1-y follow-up.

Methods:

The sample comprised 704 males and 770 females between the ages of 8 to 15 y. Clustering was defined as belonging to one or more sex and age-specific “high-risk” quartiles for biological risk factors. The longitudinal relationships were analyzed with multilevel analysis.

Results:

There was no longitudinal significant relationship between physical activity and individual biological risk factors. When biological risk factor clustering was considered, however, there was a significant longitudinal relationship with physical activity.

Conclusion:

It can be concluded that even at a young age, physical activity can play an important role in developing a healthy lifestyle profile.

Restricted access

Olga J.E. Kilkens, Britt A.J. Gijtenbeek, Jos W.R. Twisk, Willem van Mechelen and Han C.G. Kemper

The purpose of this study was (a) to investigate whether lifestyle risk factors cluster and (b) to investigate the influence of this clustering on biological CVD risk factors. This study was part of the Amsterdam Growth and Health Study (AGHS), an observational longitudinal study in which 6 repeated measurements were carried out on 181 13-year-old subjects over a period of 15 years. A longitudinal analysis (carried out with generalized estimating equations) showed no significant clustering of lifestyle risk factors at the population level. For each subject at each separate measurement period, lifestyle risk factors were summed to form a cluster score. A longitudinal linear regression analysis showed no significant relationship between the cluster score and biological CVD risk factors, except for a significant inverse relationship with cardiopulmonary fitness. In general, however, the results did not support the assumption that clustering of unhealthy lifestyle is related to biological CVD risk factors.

Restricted access

Toni A. Hilland, Nicola D. Ridgers, Gareth Stratton and Stuart J. Fairclough

The study investigated associations between selected physical activity correlates among 299 adolescents (90 boys, age 12–14 years) from 3 English schools. Physical activity was assessed by self-report and accelerometry. Correlates represented biological, predisposing, and demographic factors as described in the Youth Physical Activity Promotion Model. Boys engaged in more self-reported (p < .01) and accelerometer assessed physical activity than girls (p = .02). Positive associations between sex (male), BMI, Perceived PE Ability, Perceived PE Worth, number of enrolled students, and physical activity outcomes were evident (p < .05). School-based physical activity promotion should emphasize sex-specific enhancement of students’ perceived PE competence and enjoyment.