摘要:

The increasing number of females participating in physical activity has heightened our awareness of changes in the menstrual cycle which often accompany physical activity. As such, there has been a considerable amount of research investigating the relationships between menstrual cycle changes and bone mineral density, performance, ventilation and substrate metabolism. A number of researchers have concluded that there may be enhanced fat metabolism in eumenorrhoeic versus amenorrhoeic females, or in the follicular phase versus the luteal phase of the menstrual cycle, due to the theoretical estrogen level in eumenorrhoeic versus amenorrhoeic females or the luteal phase versus the follicular phase. However, a definite relationship between resting estrogen level and substrate metabolism has not been clearly established. In addition, the mechanisms which may be responsible for the effect of estrogen on substrate metabolism have not been addressed. It appears that the effects of estrogen on metabolism may be via the effect of estrogen on glucogenic hormones or lipolytic enzymes. Therefore, the primary purpose of this review is to explore the effects of estrogen on substrate metabolism. Menstrual cycle physiology and possible mechanisms for the effects of estrogen on metabolism, as well as previous research on estrogen and metabolism in rats and humans, will be discussed.

ISSN:0112-1642    

出版商:ADIS    

年代:2000

数据来源: ADIS

摘要:

Implicit in deciding upon an exercise test strategy to elucidate cardiopulmonary function in children with congenital heart disease are appropriate application of gas exchange techniques and the significance of the data collected to the specific congenital heart disorder. Post-operative cardiopulmonary responses to exercise in cyanotic disorders are complex and, despite a large body of extant literature in paediatric patients, there has been much difficulty in achieving quality and consistency of data.Maximal oxygen uptake is widely recognised as the best single indicator of cardiopulmonary function and has therefore been the focus of most clinical exercise tests in children. Many children with various heart anomalies are able to exercise to maximum without adverse symptoms, and it is essential that test termination is based on the same criteria for these children. Choosing appropriate, valid indicators of maximum in children with congenital heart disease is beset by difficulties.Such maximal intensity exercise testing procedures have been challenged on the grounds that they do not give a good indication of cardiopulmonary function that is relevant to real life situations. Furthermore, they are prone to much interindividual variability and error in the definition of maximal exertion. Alternative strategies have been proposed which focus upon dynamic submaximal and kinetic cardiopulmonary responses, which are thought to be less dependent on maximal voluntary effort and more suited to the daily activity patterns of children. These methods are also not without problems. Variability in anaerobic threshold measurements and controversy regarding its physiological meaning have been debated.It is recommended that an appropriate cardiopulmonary exercise gas exchange test strategy, which provides clinically useful information for children with cyanotic congenital heart disease, should include both maximal and submaximal data. The inclusion of oxygen uptake kinetics and ventilatory data are encouraged, since they may allow the distinction between a pulmonary, cardiovascular or inactivity related exercise limitation.

ISSN:0112-1642    

出版商:ADIS    

年代:2000

数据来源: ADIS

摘要:

The rate and pattern of injuries is similar in both physically-challenged and able-bodied athletic participation. However, understanding of the unique medical issues faced by physically-challenged athletes is necessary in conducting appropriate pre-participation evaluations and developing strategies for injury prevention and medical management. Review of the literature provides insight for choosing relevant tests and interpreting components of the physical examination for this population. More research is needed in the management of medical problems specific to the physically-challenged athlete.

ISSN:0112-1642    

出版商:ADIS    

年代:2000

数据来源: ADIS

摘要:

The purpose of this review is to determine how throwing overweight and underweight baseballs affects baseball throwing velocity and accuracy. Two studies examined how a warm-up with overweight baseballs affected throwing velocity and accuracy of 5oz regulation baseballs. One of these studies showed significant increases in throwing velocity and accuracy, while the other study found no significant differences. Three training studies (6 to 12 weeks in duration) using overweight baseballs were conducted to determine how they affected ball accuracy while throwing regulation baseballs. No significant differences were found in any study. From these data it is concluded that warming up or training with overweight baseballs does not improve ball accuracy. Seven overweight and 4 underweight training studies (6 to 12 weeks in duration) were conducted to determine how throwing velocity of regulation baseballs was affected due to training with these overweight and underweight baseballs. The overweight baseballs ranged in weight from 5.25 to 17oz, while the underweight baseballs were between 4 and 4.75oz. Data from these training studies strongly support the practice of training with overweight and underweight baseballs to increase throwing velocity of regulation baseballs. Since no injuries were reported throughout the training studies, throwing overweight and underweight baseballs may not be more stressful to the throwing arm compared to throwing regulation baseballs. However, since currently there are no injury data related to throwing overweight and underweight baseballs, this should be the focus of subsequent studies. In addition, research should be initiated to determine whether throwing kinematics and kinetics are different between throwing regulation baseballs and throwing overweight and underweight baseballs.

ISSN:0112-1642    

出版商:ADIS    

年代:2000

数据来源: ADIS

摘要:

Recurrent hamstring injury is a very common problem in rugby union, but has been largely ignored in the literature. It is concluded that a multifactorial aetiology may be present, and that these symptoms may be part of a continuum of symptoms that may lead to more serious injuries. Effective management needs to focus not just locally, but include proximal issues such as lumbo-pelvic stability and correcting lumbar spine dysfunction. The factors addressed in a prevention programme are likely to contribute to performance gains.

ISSN:0112-1642    

出版商:ADIS    

年代:2000

数据来源: ADIS

ISSN:0112-1642    

出版商:ADIS    

年代:2000

数据来源: ADIS