摘要:

The application of the techniques of recombinant DNA and molecular biology to molecular genetics has made it possible to identify any disease-related gene in which there is a family of 2 or more generations with 10 or more living affected individuals. Several genes have been identified that are responsible for cardiomyopathies and of particular interest is familial hypertrophic cardiomyopathy which is the most common cause of death in the athlete. Pre-screening for genetic abnormalities will be possible prior to the development of symptoms and, ultimately, such testing will also be used to specify the type of exercise to be recommended for different types of athletic training or exercise needs.

ISSN:0112-1642    

出版商:ADIS    

年代:1997

数据来源: ADIS

摘要:

Many variables have been studied pertaining to the block sprint start. Research suggests that the adoption of a medium block spacing is preferred, with front and rear knee angles in the set position approximating 90 and 130°, respectively, with the hips held moderately high. The sprinter must be capable of developing a high force rate combined with a high maximum force, especially in the horizontal direction. This ability to create high force underlies other important indicators of starting performance such as minimum block clearance time, maximum block leaving velocity and maximum block leaving acceleration. Once the sprinter has projected him/herself from the blocks at a low angle (40 to 45°) relative to the ground, the following 2 post-block steps should occur with the total body centre of gravity ahead of the contacting foot at foot strike to minimise potential horizontal braking forces.

ISSN:0112-1642    

出版商:ADIS    

年代:1997

数据来源: ADIS

摘要:

Soccer is a game with worldwide appeal. Increasing numbers of participants are members of all age groups and skill levels. The game presents to the sports medicine practitioner a wide variety of musculoskeletal and medical problems. Soccer injuries increase in frequency as the age of participant increases, with a low incidence of injury in preadolescent players. Musculoskeletal injuries most commonly affect the lower extremities and include contusions, acute and chronic musculotendinous strains, and ligamentous injuries to the knee and ankle. Most injuries are minor and respond to analgesics, therapy modalities and exercise therapy. Groin pain is a common problem and particularly prevalent among soccer players owing to the game's specific stresses. Other less common but important injuries include facial trauma, mild brain injury (concussion) and heat-related injury. Team physicians, athletic trainers and physical therapists need to possess a basic understanding of the most common injuries and problems in order to maximise safe participation for their athletes.

ISSN:0112-1642    

出版商:ADIS    

年代:1997

数据来源: ADIS

摘要:

The dual stresses of pregnancy and exercise may create conflicting physiological demands that could adversely affect pregnancy outcome. Specifically, redistribution of uterine blood flow and subsequent fetal hypoxia, hyperthermia and the risk of teratogenic effects, decreased carbohydrate availability for the fetus, and increased uterine contractility with a possible increase in risk for pre-term labour, all pose potential threats to fetal growth and development. However, despite these potential risks, literature dealing with exercise and pregnancy outcome generally shows neutral or somewhat favourable effects.A few studies have found reduced birthweight, shortened gestation, and less gestational weight gain among women who continue vigorous exercise during pregnancy compared with those who discontinue exercise or who are sedentary. However, most studies find little, if any, association between exercise and birthweight or gestational age. In contrast, studies of occupational physical activity often show an association between heavy physical work and lower birthweight and shorter gestation, especially in women in developing societies whose nutritional status may be compromised. Standing, in particular, may be associated with increased risk of prematurity. Although other outcomes, such as length of labour, type of delivery have not been well studied, there is no indication of any negative associations with exercise.There is limited evidence which suggests that exercise is related to shorter labour and is a useful treatment for gestational diabetes. Exercise is also associated with fewer symptoms and discomforts of pregnancy. This relationship is temporal in that exercise earlier in pregnancy is associated with fewer symptoms later in pregnancy. The lack of evidence for any harmful effects of exercise on pregnancy outcome indicates that, for healthy, well-nourished women, exercise during pregnancy is safe and subject to few restrictions. This conclusion is reflected in the revised, 1994 recommendations of the American College of Obstetricians and Gynecologists.

ISSN:0112-1642    

出版商:ADIS    

年代:1997

数据来源: ADIS

摘要:

The prevalence of diseases associated with obesity, such as cardiovascular disease and diabetes mellitus, is higher in the spinal cord injury (SCI) population. Specifically, the mortality rate for cardiovascular disease is 228% higher in the SCI population. In addition, 100% of SCI individuals have osteoporosis in the paralysed extremities. These diseases are related to physical activity level, the level of the spinal cord lesion, and time post injury. Physically active SCI men and women have above-average fat mass (16 to 24% and 24 to 32%, respectively, compared with 15% for able-bodied men and 23% for able-bodied women), while sedentary SCI individuals have ‘at-risk’ levels of body fat (above 25% and 32%, respectively).The proportions and densities of the 3 main constituents comprising the fat-free body (mineral, protein and water) are altered following SCI. Bone mineral content decreases by 25 to 50%, and the magnitude of reduction is dependent on the level, completeness and duration of SCI. Because of denervation resulting in skeletal muscle atrophy, total body protein reduces by 30%, and total body water relative to bodyweight decreases by 15% following SCI.Indirect methods based on 2-component body composition models assume constant proportions and densities of mineral, protein, and water in the fat-free body. As a result, prediction equations based on 2-component models yield in-valid estimates of fat and fat-free mass in the SCI population. Therefore, future research needs to directly quantify the proportions and densities of the constituents of the fat-free body in the SCI population relative to age, sex, physical activity level, level of the spinal cord lesion and time post injury, and to develop equations based on multicomponent body composition models.

ISSN:0112-1642    

出版商:ADIS    

年代:1997

数据来源: ADIS

摘要:

The biphasic ultrastructure of the meniscus and of articular cartilage provides their function in the complex biomechanics of the knee joint including load distribution, shock absorption, viscoelasticity, a smooth low friction gliding surface and resilience to compression. Meniscectomy may lead to destruction of cartilage and to osteoarthritis of the knee joint. Osteoarthritic changes after meniscectomy have been reported in up to 89% of patients.Retrospective analysis after open or arthroscopically assisted meniscectomy revealed restriction in sports to be between 2 and 50% and cessation of sports to be between 2 and 25%. Generally, patients with degenerative changes at the time of surgery are reported to have lower knee joint function and to resume sports activities later.Pharmalogical measures to treat osteoarthritis following previous meniscectomy include pain medication and intra-articular drug administration. Additionally, range of motion and strengthening exercises and moderate athletic activities are recommended. When surgery is considered, correctional osteomies and unicompartmental or total knee arthroplasty depending on the degree of osteoarthritis are preferred.

ISSN:0112-1642    

出版商:ADIS    

年代:1997

数据来源: ADIS