ISSN:0112-1642    

出版商:ADIS    

年代:1997

数据来源: ADIS

摘要:

Described nearly 70 years ago as the ‘punch drunk’ syndrome, dementia pugilistica has recently received increasing attention in both the medical and lay press. The association between the finding of cavum septi pellucidi and dementia in old boxers was first described by Ferguson and Mawdsley in 1965. Since then it has commonly been listed as one of the features of this condition. We review the significance and the epidemiology of cavum septi pellucidi and present an alternative explanation for the association between this developmental anomaly of the brain and dementia pugilistica.

ISSN:0112-1642    

出版商:ADIS    

年代:1997

数据来源: ADIS

摘要:

Many types of drugs are used by athletes to improve performance. This paper reviews the literature on 3 categories of drugs: those that enhance performance as stimulants (amphetamines, ephedrine, and cocaine), those that are used to reduce tremor and heart rate (&bgr;-blockers) and those involved in bodyweight gain or loss (anabolic-androgenic steroids, growth hormone, &bgr;2-agonists, and diuretics). Limitations of research on these drugs as they relate to performance enhancement are also discussed.The numerous studies that have assessed the effects of amphetamines on performance report equivocal results. This may be due to the large interindividual variability in the response to the drug and the small sample sizes used. Most studies, however, show that some individuals do improve exercise performance when taking amphetamines, which may be attributed to their role in masking fatigue. As a stimulant, ephedrine has not been found to improve performance in the few studies available. More recently, ephedrine has been purported to be effective as a fat burner and used by athletes to maintain or improve muscle mass. Although research on individuals with obesity supports the use of ephedrine for fat loss, no studies have been done on athletes. The few studies of cocaine and exercise suggest that little to no performance gains are incurred from cocaine use. Moreover, the sense of euphoria may provide the illusion of better performance when, in actuality, performance was not improved or was impaired.&bgr;-Blockers have been found to reduce heart rate and tremor and to improve performance in sports that are not physiologically challenging but require accuracy (e.g. pistol shooting). However, there is evidence that some individuals may be high responders to &bgr;-blockers to the extent that their heart rate response is so blunted as to impair performance.Although equivocal, several studies have reported that anabolic-androgenic steroids increase muscle size and strength. However, most studies are not well controlled and use insufficient drug doses. One recent well controlled study did find an increase in muscle mass and strength with supraphysiological doses, and the improvements were greater in participants who were also resistance training. There is little information available on the effects of growth hormone on muscle mass or performance in athletes, although data suggest that growth hormone administration does not increase muscle protein synthesis. &bgr;2-Agonists, such as clenbuterol and salbutamol, when administered orally appear to improve muscular strength due to their potential role in increasing muscle mass. However, studies have not been done using athletes. Diuretics result in a loss of body water and hence bodyweight that can be advantageous for sports with strict bodyweight classifications. There is insufficient evidence on possible performance decrements in the field that could result from dehydration induced by the diuretics.Overall, the most significant concern in studies of drug use is the large inter-individual variability in responses to a drug. Further studies are needed to understand why some individuals are more responsive than others and to assess whether the responses are consistent for a given individual. Most studies of drug effectiveness have not used athletes. The effectiveness of many drugs may be reduced in highly trained athletes because there is a lower margin for improvement.

ISSN:0112-1642    

出版商:ADIS    

年代:1997

数据来源: ADIS

摘要:

Peripheral nerves are susceptible to injury in the athlete because of the excessive physiological demands that are made on both the neurological structures and the soft tissues that protect them. The common mechanisms of injury are compression, traction, ischaemia and laceration. Seddon's original classification system for nerve injuries based on neurophysiological changes is the most widely used. Grade 1 nerve injury is a neuropraxic condition, grade 2 is axonal degeneration and grade 3 is nerve transection.Peripheral nerve injuries are more common in the upper extremities than the lower extremities, tend to be sport specific, and often have a biomechanical component. While the more acute and catastophic neurological injuries are usually obvious, many remain subclinical and are not recognised before neurological damage is permanent. Early detection allows initiation of a proper rehabilitation programme and modification of biomechanics before the nerve injury becomes irreversible. Recognition of nerve injuries requires an understanding of peripheral neuroanatomy, knowledge of common sites of nerve injury and an awareness of the types of peripheral nerve injuries that are common and unique to each sport.The electrodiagnostic exam, usually referred to as the ‘EMG’, consists of nerve conduction studies and the needle electrode examination. It is used to determine the site and degree of neurological injury and to predict outcome. It should be performed by a neurologist or physiatrist (physician specialising in physical medicine and rehabilitation), trained and skilled in this procedure. Timing is essential if the study is to provide maximal information. Findings such as decreased recruitment after injury and conduction block at the site of injury may be apparent immediately after injury but other findings such as abnormal spontaneous activity may take several weeks to develop. The electrodiagnostic test assists with both diagnosis of the injury and in predicting outcome.Proximal nerve injuries have a poorer prognosis for neurological recovery. The most common peripheral nerve injury in the athlete is the burner syndrome. Though primarily a football injury, burners have been reported in wrestling, hockey, basketball and weight-lifting as a result of acute head, neck and/or shoulder trauma. Most burners are self-limiting, but they occasionally produce permanent neurological deficits. The axillary nerve is commonly injured with shoulder dislocations but is also susceptible to injury by direct compression. The sciatic and common peroneal nerves can be injured by trauma. The suprascapular, musculocutaneous, ulnar, median and tibial nerves are susceptible to entrapment. The long thoracic and femoral nerves can be injured by severe traction.

ISSN:0112-1642    

出版商:ADIS    

年代:1997

数据来源: ADIS

摘要:

Orienteering is an endurance running event which differs from other running sports both in its cognitive element and in the type of terrain encountered. The demands of overcoming this terrain are not manifest in significant differences between orienteers and road runners in somatotype, though elite female orienteers have consistently been shown to have higher levels of adiposity (>19%) than elite road runners. High aerobic power in orienteers (up to 63 and 76 ml/kg/min in women and men, respectively) is coupled with lower anaerobic performance. While leg strength is generally not high when compared with other athletic specialities, female orienteers have relatively good leg flexion strength.The energy cost of running is greatly increased in rough terrain. Oxygen cost was 26% higher while running in a forest when compared with road running. Biomechanical differences in stride pattern contribute towards this increased demand. Despite the high energy demands during competition, orienteers pace themselves such that their mean heart rate remains within the range of 167 to 172 beats/min, despite large fluctuations. The rough terrain encountered in orienteering results not only in a high energy cost but also in a higher incidence of sport-specific injuries, particularly to the ankle. Minor injuries such as cuts and bruises are common during competition.

ISSN:0112-1642    

出版商:ADIS    

年代:1997

数据来源: ADIS

摘要:

Stress fractures are a common overuse injury among athletes. The incidence of stress fractures among females is higher in the military, but this difference is not as evident in the athletic population. The history of the patient with stress fracture is typically one of insidious onset of activity-related pain. If the patient continues to exercise, the pain may well become more severe or occur at an earlier stage of exercise. As well as obtaining a history of the patient's pain and its relation to exercise, it is important to determine the presence of predisposing factors. On physical examination, the most obvious feature is localised bony tenderness. Occasionally, redness, swelling or periosteal thickening may be present at the site of the stress fracture. The diagnosis of stress fracture is primarily a clinical one; however, if the diagnosis is uncertain, various imaging techniques can be used to confirm the diagnosis. In the majority of stress fractures, there is no obvious abnormality on plain radiograph. Although the triple phase bone radiograph is extremely sensitive, the fracture itself is not visualised and it may be difficult to precisely locate the site, especially in the foot. The radionuclide scan will detect evolving stress fractures at the stage of accelerated remodelling, so the findings must be closely correlated with the clinical picture. The characteristic bone scan appearance of a stress fracture is of a sharply marginated area of increased uptake, usually involving one cortex of the bone. Computerised tomography scanning is a helpful addition if the fracture needs to be visualised, or to distinguish between a stress reaction and stress fracture. Magnetic resonance imaging (MRI) is being used increasingly as the investigation of choice for stress fractures. The typical findings on MRI are of periosteal and marrow oedema, as well as fracture line. The basis of treatment of a stress fracture involves rest from the aggravating activity. Most stress fractures will heal in a straightforward manner, and return to sport occurs within 6 to 8 weeks. The rate of resumption of activity should be influenced by symptoms and physical findings. When free of pain, the aggravating activity can be resumed and slowly increased. It is important that the athlete with a stress fracture maintain fitness during this period of rehabilitation. The most commonly used methods are cycling, swimming, upper body weights and water running. There are a number of specific stress fractures that require additional treatment because of a tendency to develop delayed union or nonunion. These include stress fractures of the neck of the femur, anterior cortex of the tibia, navicular and second and fifth metatarsals. An essential component of the management of stress fractures, as with any overuse injury, involves identification of the factors that have contributed to the injury and, where possible, correction or modification of some of these factors to reduce the risk of the injury recurring. Stress fractures are more common in female athletes with menstrual disturbances. This may be due to the effect on bone density. The role of hormonal replacement in the management of these athletes is unclear at this stage.

ISSN:0112-1642    

出版商:ADIS    

年代:1997

数据来源: ADIS