ISSN:0112-1642    

DOI:10.2165/00007256-199519010-00001

出版商:Springer International Publishing    

年代:2012

数据来源: ADIS

摘要:

SummaryEndurance training can lead to what has been termed ‘sports anaemia’. Although under normal conditions, red blood cells (RBCs) have a lifespan of about 120 days, the rate of aging may increase during intensive training. However, RBC deficiency is rare in athletes, and sports anaemia is probably due to an expanded plasma volume. Cycling, running and swimming have been shown to cause RBC damage.While most investigators measure indices of haemolysis (for example, plasma haemoglobin or haptoglobin), RBC removal is normally an extravascular process that does not involve haemolysis. Attention is now turning to cellular indices (such as antioxidant depletion, or protein or lipid damage) that may be more indicative of exercise-induced damage.RBCs are vulnerable to oxidative damage because of their continuous exposure to oxygen and their high concentrations of polyunsaturated fatty acids and haem iron. As oxidative stress may be proportional to oxygen uptake, it is not surprising that antioxidants in muscle, liver and RBCs can be depleted during exercise. Oxidative damage to RBCs can also perturb ionic homeostasis and facilitate cellular dehydration. These changes impair RBC deformability which can, in turn, impede the passage of RBCs through the microcirculation. This may lead to hypoxia in working muscle during single episodes of exercise and possibly an increased rate of RBC destruction with long term exercise. Providing RBC destruction does not exceed the rate of RBC production, no detrimental effect to athletic performance should occur. An increased rate of RBC turnover may be advantageous because young cells are more efficient in transporting oxygen.Because most techniques examine the RBC population as a whole, more sophisticated methods which analyse cells individually are required to determine the mechanisms involved in exercise-induced damage of RBCs.

ISSN:0112-1642    

DOI:10.2165/00007256-199519010-00002

出版商:Springer International Publishing    

年代:2012

数据来源: ADIS

摘要:

SummaryThe development of simple, noninvasive tests of work capacities, underpinned primarily by anaerobic metabolism, proliferated in the early 1970s. A 30-second maximal cycle test developed at the Wingate Institute initiated efforts to develop work tests of anaerobic capacities. Such tests can be developed using any ergometer which simulates competitive conditions and enables an accurate determination of mechanical work output. A 10-second all-out test is commonly used to measure maximal work output generated primarily via the hydrolysis of high-energy Phosphagens (i.e. the alactic work capacity). In contrast, a variety of constant-load and all-out tests of anaerobic (alactic plus lactic) work capacity have been proposed. It has been suggested that all-out tests provide more information about physiological capabilities and are easier to apply than constant-load tests. The optimal duration for an all-out test of anaerobic work capacity is proposed at 30 seconds, a duration which may also provide the basis for the development of accurate field tests of anaerobic capacity. There is evidence that the y-intercept of the maximal work-derivation regression is a valid work estimate of anaerobic capacity in athletes, although its utility is undermined by the number of tests required for its derivation.

ISSN:0112-1642    

DOI:10.2165/00007256-199519010-00003

出版商:Springer International Publishing    

年代:2012

数据来源: ADIS

摘要:

SummaryRegular exercise has been recognised as an important component in the management of patients with diabetes mellitus. In addition to acutely lowering blood glucose, exercise training improves glucose tolerance and peripheral insulin sensitivity, contributes to weight loss and reduces several risk factors for cardiovascular disease. When proper precautions are taken to prevent hypoglycaemia, individuals with diabetes can enjoy the same benefits from exercise as nondiabetic healthy individuals. As a guideline, moderate intensity, aerobic endurance activities should be performed for 20 to 40 minutes at least 3 times a week. Blood glucose should be monitored, and insulin dose and carbohydrate intake adjusted based on the blood glucose response to the type and duration of exercise. This review will summarise current understanding of the therapeutic role of exercise in the treatment of diabetes and will present guidelines for prescribing exercise in diabetic patients.

ISSN:0112-1642    

DOI:10.2165/00007256-199519010-00004

出版商:Springer International Publishing    

年代:2012

数据来源: ADIS

摘要:

SummaryLearning disability is characterised by a discrepancy between achievement and assessed intellectual ability. Children with this problem commonly (but not invariably) show impaired motor proficiency, as assessed by such instruments as the Bruininks-Oseretsky Test of motor proficiency. It has been hypothesised that poor motor performance and/or poor social skills lead to exclusion from games, creating a vicious cycle of decreasing participation, decreasing competence, a deterioration of self-worth and increasing social maladjustment.Attempts to break the vicious cycle with programmes designed to enhance motor proficiency have been uniformly unsuccessful. There is limited experimental evidence to support the view that structured physical activity programmes with an embedded social skills training component can be an effective method of enhancing both actual motor ability and self-perception of physical and academic competence. However, a controlled comparison with small-group, academic instruction has shown that, from the educational perspective, a physical activity-based intervention is no more effective than other forms of special attention. The main argument for delivering social skills training through a physical activity programme lies not in a unique impact upon learning disability, but rather in terms of the other well-established long term health benefits of exercise.

ISSN:0112-1642    

DOI:10.2165/00007256-199519010-00005

出版商:Springer International Publishing    

年代:2012

数据来源: ADIS

摘要:

SummarySkier’s thumb is an injury to the ulnar collateral ligament (UCL) of the thumb metacarpophalangeal joint (MCPJ) which has a serious risk of disabling chronic instability if not treated adequately. The lesion most often occurs in skiers when the ski pole forces the thumb to deviate radially. Strapless poles do not decrease the incidence of skier’s thumb, but if skiers are trained to discard the pole during a fall the risk might be reduced. Clinical and anatomical findings and the understanding of the injury mechanism show that stability testing (performed with the joint in full flexion) and additional standard radiographs remain the keystones in decision making in all MCPJ sprains. Protective splinting is advocated in stable, undisplaced avulsion fractures and incomplete ligamentous lesions of the UCL. However, surgery should not be delayed where there are displaced bony avulsion fractures, and where a complete ligamentous rupture is suspected because of a more than 30° stressed radial deviation and more than 20° difference compared with the uninjured side. Controlled active range of motion exercises can usually be started 3 to 4 weeks after the injury or open surgical repair, respectively. Protective splinting is continued until the sixth week and unrestricted use allowed 12 weeks following injury.

ISSN:0112-1642    

DOI:10.2165/00007256-199519010-00006

出版商:Springer International Publishing    

年代:2012

数据来源: ADIS