摘要:

The use of local anaesthetic painkilling injections in professional football can counter the performance-reducing impact of injury and lower the rate of players missing matches through injury. In the majority of cases, these injections are probably safe, although scientific evidence in this area is scant, particularly regarding long-term follow-up. The known long-term injury sequelae of professional football, such as increased rates of osteoarthritis of the knee (in particular), hip, ankle and lumbar spine, do not generally relate to the injuries for which local anaesthetic is commonly used. The most commonly injected injuries (acromioclavicular joint sprains, finger and rib injuries and iliac crest haematomas) are probably the safest to inject. There are risks of worsening injuries and known specific complications when local anaesthetic is used, and players requesting injections should be made aware of these. Local anaesthetic injections as painkillers should only be used when both the doctor and player consider that the benefits clearly outweigh the anticipated possible risks. Intra-articular injections to the knee, ankle, wrist, joints of the foot, and to the pubic symphysis and major tendons of the lower limb are best avoided in most circumstances. To enable the benefit and risk profile of local anaesthetic injections to be better understood, it is recommended that professional football competitions make local anaesthetics legal only with compulsory notification.

ISSN:0112-1642    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

In humans, decreases in cardiac output play an important role in the age-related decrease in whole-body oxidative capacity. What remains less clear is whether a decline in skeletal muscle oxidative capacity is also an inevitable consequence of aging, as a number of other factors that could affect oxidative capacity also change with age, including: physical activity, health status, fibre-type composition, rates of protein synthesis and muscle blood supply. Bothin vitrostudies using muscle biopsy tissue andin vivostudies using31P-magnetic resonance spectroscopy are used to study muscular oxidative capacity. Using these methodologies, researchers have found age-associated reductions in the oxidative capacities of specific muscles. In most cases, however, the influence of physical activity has not been adequately controlled, making it difficult to evaluate the effects of age itself from those of lifestyle changes associated with aging.Upon critical evaluation of the existing literature, the following picture regarding the effect of age on muscle oxidative capacity appears: although the maximum level of muscular oxidative capacity attainable through training may decline with age, much of the age-associated decline in oxidative function is related to the reductions in fitness and/or habitual physical activity that typically occur in this population. Future studies in this area must account for the health and activity status of their study participants.

ISSN:0112-1642    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

This review focuses on possible pathophysiology of exercise-associated hyponatraemia and its implication on evaluation and treatment of collapsed athletes during endurance events. Rehydration guidelines and field care have traditionally been based on the belief that endurance events create a state of significant fluid deficit in athletes, which must be corrected by liberal hydration. Beliefs in the necessity of liberal hydration may have contributed to cases of hyponatraemia. Assumptions that fluid loss accounts for the entire weight loss during exercise and that fluid ingestion is the only source of water gain during exercise may lead to an overestimation of the degree of volume depletion and the amount of fluid needed for replacement.Increasing evidence suggests that hyponatraemic athletes are fluid overloaded; ingestion of large amount of hypotonic fluid in combination with inappropriate or inadequate physiological responses leads to excessive retention of free fluid. Risk factors include hot weather, female sex, slower finishing time, and possibly the use of nonsteroidal anti-inflammatory medications. Symptoms of hyponatraemia can be subtle and can mimic those of other exercise-related illnesses, thereby complicating its diagnosis and leading to possible inappropriate treatment. Most athletes who collapse at the finish line experience exercise-associated collapse, a benign and transient form of postural hypotension that can be treated simply by continued ambulation after finishing or elevation of legs while in a supine position for those who cannot walk.Care providers should consider the use of intravenous hydration with normal saline carefully since it is not needed by most collapsed athletes and may worsen the condition of patients with unsuspected hyponatraemia. Historic information and clinical signs of volume depletion should be elicited prior to its use. Most hyponatraemic athletes will recover uneventfully with careful observation while awaiting spontaneous diuresis. Use of hypertonic saline should be reserved for patients with severe symptoms. Moderate consumption of carbohydrate-electrolyte solution during exercise may allow the maintenance of adequate hydration and the prevention of hyponatraemia.

ISSN:0112-1642    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

Physical activity has been shown to reduce risk of colon cancer. Some studies have shown site-specific associations while others have not. The inverse association between physical activity and colon cancer is consistent although only 7 of 13 studies that have collected both colon and rectal cancer data in the same manner report reduced risk for rectal cancer; four of these studies detected statistically significant inverse associations. The frequency, duration and intensity of activity are important components of a public health message to reduce risk of colon cancer through performance of physical activity. However, difficulties in estimating the exact amount of activity needed and frequency and intensity of activity result in only crude estimates of dose needed for a protective effect. Much of the literature suggest that more intense activity is needed to reduce colon cancer risk and that somewhere between 3.5 and 4 hours of vigorous activity per week may be needed to optimise protection. Several biological mechanisms have been proposed to explain the association between physical activity and colon cancer; many of these mechanisms also support the observation that intense activities are most protective. Biological mechanisms include: physical activity increasing gut motility; enhancing the immune system; decreasing insulin and insulin-like growth factor levels; decreasing obesity; enhancing free radical scavenger systems; and influencing prostaglandin levels. The evidence taken together provides strong support for lack of physical activity being causally related to colon cancer. It has been estimated that 12–14% of colon cancer could be attributed to lack of frequent involvement in vigorous physical activity.

ISSN:0112-1642    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

The twitch interpolation technique is commonly employed to assess the completeness of skeletal muscle activation during voluntary contractions. Early applications of twitch interpolation suggested that healthy human subjects could fully activate most of the skeletal muscles to which the technique had been applied. More recently, however, highly sensitive twitch interpolation has revealed that even healthy adults routinely fail to fully activate a number of skeletal muscles despite apparently maximal effort. Unfortunately, some disagreement exists as to how the results of twitch interpolation should be employed to quantify voluntary activation. The negative linear relationship between evoked twitch force and voluntary force that has been observed by some researchers implies that voluntary activation can be quantified by scaling a single interpolated twitch to a control twitch evoked in relaxed muscle.Observations of non-linear evoked-voluntary force relationships have lead to the suggestion that the single interpolated twitch ratio can not accurately estimate voluntary activation. Instead, it has been proposed that muscle activation is better determined by extrapolating the relationship between evoked and voluntary force to provide an estimate of true maximum force. However, criticism of the single interpolated twitch ratio typically fails to take into account the reasons for the non-linearity of the evoked-voluntary force relationship. When these reasons are examined, it appears that most are even more challenging to the validity of extrapolation than they are to the linear equation. Furthermore, several factors that contribute to the observed non-linearity can be minimised or even eliminated with appropriate experimental technique. The detection of small activation deficits requires high resolution measurement of force and careful consideration of numerous experimental details such as the site of stimulation, stimulation intensity and the number of interpolated stimuli. Sensitive twitch interpolation techniques have revealed small to moderate deficits in voluntary activation during brief maximal efforts and progressively increasing activation deficits (central fatigue) during exhausting exercise. A small number of recent studies suggest that resistance training may result in improved voluntary activation of the quadriceps femoris and ankle plantarflexor muscles but not the biceps brachii. A significantly larger body of evidence indicates that voluntary activation declines as a consequence of bed-rest, joint injury and joint degeneration. Twitch interpolation has also been employed to study the mechanisms by which caffeine and pseudoephedrine enhance exercise performance.

ISSN:0112-1642    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

Knee ligament injuries often result in a premature end to a career in sports. The treatment after rupture of the anterior cruciate ligament (ACL) may be operative or conservative. In both cases, the goal is to reach the best functional level for the patient without risking new injuries or degenerative changes in the knee. Return to high level of athletic activity has been an indicator of treatment success. Rehabilitation is an important part of the treatment. Knowledge of healing processes and biomechanics in the knee joint after injury and reconstruction, together with physiological aspects on training effects is important for the construction of rehabilitation programmes. Current rehabilitation programmes use immediate training of range of motion. Weight bearing is encouraged within the first week after an ACL reconstruction. Commonly, the patients are allowed to return to light sporting activities such as running at 2–3 months after surgery and to contact sports, including cutting and jumping, after 6 months. In many cases, the decisions are empirically based and the rehabilitation programmes are adjusted to the time selected for returning to sports. In this article, some criteria that should be fulfilled in order to allow the patient to return to sports are presented. Surgery together with completed rehabilitation and sport-specific exercises should result in functional stability of the knee joint. In addition, adequate muscle strength and performance should be used as a critical criterion. Other factors, such as associated injuries and social and psychological hindrances may also influence the return to sports and must be taken into consideration, both during the rehabilitation and at the evaluation of the treatment.

ISSN:0112-1642    

出版商:ADIS    

年代:2004

数据来源: ADIS