摘要:

The elderly population is growing both in size and in proportion of the total population. The costs to the community of the elderly being in poor health are also growing proportionately. The beneficial effects of exercise on various physiological and psychological parameters in the elderly have been well established. The effects of exercise on the mobility and independence of the elderly are also of primary concern, their maintenance being an important exercise goal. Impaired balance and gait are the 2 most significant risk factors for limited mobility and falls in the elderly. It is important to understand the effects of aging and exercise on these risk factors.

ISSN:0112-1642    

出版商:ADIS    

年代:2000

数据来源: ADIS

摘要:

Exercise physiologists, coaches and athletes have traditionally used heart rate (HR) to monitor training intensity during exercise. While it is known that aerobic training decreases submaximal HR (HRsubmax) at a given absolute exercise workload, the general consensus is that maximum HR (HRmax) is relatively unaltered regardless of training status in a given population. It has not been seriously postulated as to whether HRmaxcan change modestly with aerobic training/detraining. Despite several sources stating that HRmaxis unaltered with training, several studies report that HRmaxis reduced following regular aerobic exercise by sedentary adults and endurance athletes, and can increase upon cessation of aerobic exercise. Furthermore, evidence suggests that tapering/detraining can increase HRmax. Therefore, it is plausible that some of the same mechanisms that affect both resting and HRsubmaxmay also play a role in altered HRmax. Some of the proposed mechanisms for changes in HRmaxthat may occur with aerobic training include autonomic (extrinsic) factors such as plasma volume expansion and enhanced baroreflex function, while some nonautonomic (intrinsic) factors are alteration of the electrophysiology of the sinoatrial (SA) node and decreased ß-adrenergic receptor number and density. There is a high correlation between changes in both maximal oxygen uptake (V-dot2max) and HRmaxthat occurs with training, tapering and detraining (r = −0.76; p < 0.0001; n = 314), which indicates that as V-dot2maximproves with training, HRmaxtends to decrease, and when detraining ensues, HRmaxtends to increase. The overall effect of aerobic training and detraining on HRmaxis moderate: effect sizes based on several studies were calculated to be −0.48 and +0.54, respectively. Therefore, analysis reveals that HRmaxcan be altered by 3 to 7% with aerobic training/detraining. However, because of a lack of research in the area of training on HRmax, the reader should remain speculative and allow for cautious interpretation until further, more thorough investigations are carried out as to the confirmation of mechanisms involved. Despite the limitations of using HR and HRmaxas a guide to training intensity, the practical implications of monitoring changing HRmaxare: (i) prescribed training intensities may be more precisely monitored; and (ii) prevention of overtraining may possibly be enhanced. As such, it may be sensible to monitor HRmaxdirectly in athletes throughout the training year, perhaps at every macrocycle (3 to 6 weeks).

ISSN:0112-1642    

出版商:ADIS    

年代:2000

数据来源: ADIS

摘要:

While the crucial role of haemoglobin in aerobic exercise has been well accepted, there is still a great deal of controversy about the optimal haematological parameters in the athletic population. The initial part of this review will examine the question of anaemia in athletes. The most common finding in athletes is a dilutional pseudoanaemia that is caused by a plasma volume expansion, rather than an actual blood loss. It is not a pathological state and normalises with training cessation in 3 to 5 days. This entity should be distinguished from conditions associated with lowered blood counts, such as intravascular haemolysis or iron deficiency anaemia. The evaluation of true anaemia states in the athlete must take into account not only blood losses secondary to exercise, such as foot strike haemolysis or iron losses through sweat, but non-athletic causes as well. Depending on the age and sex of the athlete, consideration must be given to evaluation of the gastrointestinal or genitourinary systems for blood loss. Finally, a comprehensive nutritional history must be taken, as athletes, especially women, are frequently not consuming adequate dietary iron.The second section of the paper will deal with the very contentious issue of sickle cell trait. While there have been studies demonstrating an increased risk of sudden death in people with sickle cell trait, it is still quite rare and should not be used as a restriction to activity. Further, studies have demonstrated that patients with sickle cell trait have an exercise capacity that is probably normal or near normal. However, in the cases of sudden death, it has been secondary to rhabdomyolysis occurring among sickle cell trait athletes performing at intense exertion under hot conditions, soon after arriving at altitude. The recommendations are that athletes with sickle cell trait adhere to compliance with the general guidelines for fluid replacement and acclimatisation to hot conditions and altitude.The final section of the paper examines the issue of haematological manipulation for the purposes of ergogenic improvement. Although experiments with blood doping revealed improvements in running time to exhaustion and maximal oxygen uptake, the introduction of recombinant erythropoietin has rendered blood doping little more than a historical footnote. However, the improvements in performance are not without risk, and the use of exogenous erythropoietin has the potential for increased viscosity of the blood and thrombosis with potentially fatal results. Until a definitive test is developed for detection of exogenous erythropoietin, it will continue to be a part of elite athletics.

ISSN:0112-1642    

出版商:ADIS    

年代:2000

数据来源: ADIS

摘要:

Following menopause, women show an increased risk of heart disease to a level equal that of men. This elevated risk is thought to be due, at least partly, to changes in blood lipid and fibrinogen levels. The purpose of this article is to review the published research on the relationship between both exercise and hormone replacement with regards to common cardiovascular disease (CVD) risk factors and the relative importance of each.Menopause is associated with increased total serum cholesterol, triglycerides and fibrinogen, and a decrease in high density lipoprotein (HDL) cholesterol levels. The major reason for these changes following menopause is believed to be a result of fluctuations in hormonal status, primarily a deficiency in estrogen. Intervention may be justified since estrogen replacement therapy has been shown to decrease the risk of developing CVD and to have a significant impact on many of the CVD risk factors. The results vary from study to study, but generally estrogen replacement has been found to decrease total cholesterol and fibrinogen, while increasing HDL cholesterol and triglycerides. All of these changes, other than the increase in triglycerides, are seen as positive. The addition of progestogen to estrogen may negate some of the beneficial changes of estrogen, most notably the increase in HDL cholesterol levels. However, progestogen has also been reported to offset the increase in triglycerides seen with unopposed estrogen replacement. Thus, there are contradictory effects (both positive and negative) of hormone replacement on CVD risk factors in women.Regular aerobic exercise and resulting improvements in cardiorespiratory fitness have consistently been shown as preventive of CVD. This decreased CVD risk is in part because of the impact of exercise on blood lipids and fibrinogen. Increased aerobic exercise is thought to improve the risk profile, mainly through an increase in HDL cholesterol levels and decreases in triglycerides and fibrinogen. Unfortunately, the majority of research supporting the effects of exercise on CVD risk factors has been done on men. Even when research has included women, very few studies have focused on postmenopausal women. However, the research done on postmenopausal women points to a significantly improved CVD risk factor profile with regular cardiorespiratory exercise.

ISSN:0112-1642    

出版商:ADIS    

年代:2000

数据来源: ADIS

摘要:

The documentation of anterior cruciate ligament (ACL) injuries in the skeletally immature athlete has significantly increased over the past decade, primarily due to increased awareness of these injuries within this younger athletic population. The evaluation of these injuries are similar to that in the adult population. Diagnostic studies such as plain radiographs, as well as magnetic resonance imaging, can delineate the location of the ACL failure. Physical presentation most commonly includes an acute haemarthrosis and ligamentous insufficiency. Several studies have demonstrated that the diagnostic reliability of the physical examination is poor in children, especially in patients less than 12 years old. The site of ACL failure in this adolescent population is most commonly at the tibial insertion. We recommend arthroscopic or arthroscopically assisted open reduction and internal fixation with nonabsorbable sutures for all displaced tibial eminence fractures. Mid-substance ACL failures also occur in this athletic age group. The association of meniscal injuries with these ACL failures appears to be greater than 50%. Historically, poor subjective and objective outcomes have been associated with primary and extra-articular repairs. Intra-articular reconstruction is the gold standard. The issue of placing the graft across open physeal plates is under investigation. Recent animal studies as well as human clinical series have demonstrated safety in placing soft tissue, i.e. hamstring grafts, across open growth plates without subsequent angular or leg length discrepancy. Historically, non-operatively treated ACL failures are associated with poor functional outcomes as well as a high incidence of meniscal re-injury. If the treatment of an adolescent athlete with an ACL failure is to be rehabilitation until skeletal maturity, close follow-up is essential to detect functional instability, which may prompt earlier surgical reconstruction.

ISSN:0112-1642    

出版商:ADIS    

年代:2000

数据来源: ADIS

摘要:

Arthroscopy of the foot and ankle is a valuable tool for treating athletic foot injuries. The ability to evaluate and treat injuries without an extensive open approach is very important when dealing with the athletic population, allowing a much quicker rehabilitation and return to sport. The diagnostic and therapeutic indications for foot and ankle arthroscopy have increased significantly over recent years. Techniques and instrumentation have become more advanced and more readily available to the orthopaedist. This article defines the conditions in which arthroscopy is appropriate and presents current techniques for treatment.

ISSN:0112-1642    

出版商:ADIS    

年代:2000

数据来源: ADIS