摘要:

Exercise-induced arterial endofibrosis (EIAE) is now a 20-year-old concept. Initially observed in highly trained cyclists, it has been found in many other male and female endurance athletes. Most stenoses are located on the first centimetres of the external iliac artery but other localisation may be found. The disease is defined by specific histological findings showing fibrosis of the intimal and medial wall of the artery. Ankle pressure measurement plays a key role in the diagnosis of EIAE provided that the exercise tests reproduce symptoms and are performed with the subject being highly trained, and that pressure measurements are performed early following exercise. Various cut-off values have been proposed in the literature.Magnetic resonance imaging or arteriography or ultrasound imaging should be performed by trained operators only. Surgical ‘endofibrosectomy’ is preferable in young cyclists generally associated with a saphenous enlargement patch. We do not recommend angioplasty. Athletes are generally allowed to return to competition within 3–4 months following surgery. Many unanswered questions remain, specifically about the pathophysiology of this disease. Mechanical and pressure strain play a central role in the development of EIEA, but nutritional and haemorrheological factors, hormonal changes and a genetic predisposition are likely to contribute. New techniques could facilitate the diagnosis of EIAE.

ISSN:0112-1642    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

Approximately one in five top-level cyclists will develop sports-related flow limitations in the iliac arteries. These flow limitations may be caused by a vascular lumen narrowing due to endofibrotic thickening of the intima and/or by kinking of the vessels. In some athletes, extreme vessel length contributes to this kinking. Endofibrotic thickening is a result of a repetitive vessel damage due to haemodynamic and mechanical stress. Atherosclerotic intimal thickening is seldom encountered in these young athletes. This type of sports-related flow limitation shows no relationship with the classical risk factors for atherosclerosis like smoking, hypercholesterolaemia or family predisposition for arterial diseases.The patient’s history is paramount for diagnosis. If an athlete reports typical claudication-like complaints in a leg at maximal effort, which disappear quickly at rest, approximately two out of three will have a flow limitation in the iliac artery. In current (sports) medical practice, this diagnosis is often missed, since a vascular cause is not expected in this healthy athletic population. Even if suspected, the routinely available diagnostic tests often appear insufficient. Definite diagnosis can be made by a combination of the patient’s history and special designed tests consisting of a maximal cycle ergometer test with ankle blood pressure measurements and/or an echo-Doppler examination with provocative manoeuvres like hip flexion and exercise.Conservative treatment consists of diminishing or even completely stopping the provocative sports activity. If conservative treatment is insufficient or deemed unacceptable, surgical treatment might be considered. As surgery needs to be tailored to the underlying lesions, a detailed analysis before surgery is necessary. Standard clinical tests, used for visualising atherosclerotic diseases, are inadequate to identify and quantify the causes of flow limitations. Echo-Doppler examination and magnetic resonance angiography with both flexed and extended hips have been proven to be adequate tools. In particular, overprojection and eccentric location of the lesions seriously limit the usefulness of a two-dimensional technique like digital subtraction angiography.In the early stages, when kinking has not yet led to intimal thickening or excessive lengthening, simple surgical release of the iliac artery is effective. However, for patients with excessive vessel lengths or extensive endofibrotic thickening, a vascular reconstruction may be necessary. A major drawback of these interventions is that long-term effects and complications are unknown.As both the diagnostic methods and the treatments for this type of flow limitation differ substantially from routine vascular procedures, these patients should be examined in specialised research centres with appropriate diagnostic tools and medical experience.

ISSN:0112-1642    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

It is generally accepted that increasing the flexibility of a muscle-tendon unit promotes better performances and decreases the number of injuries. Stretching exercises are regularly included in warm-up and cooling-down exercises; however, contradictory findings have been reported in the literature. Several authors have suggested that stretching has a beneficial effect on injury prevention. In contrast, clinical evidence suggesting that stretching before exercise does not prevent injuries has also been reported. Apparently, no scientifically based prescription for stretching exercises exists and no conclusive statements can be made about the relationship of stretching and athletic injuries. Stretching recommendations are clouded by misconceptions and conflicting research reports. We believe that part of these contradictions can be explained by considering the type of sports activity in which an individual is participating. Sports involving bouncing and jumping activities with a high intensity of stretch-shortening cycles (SSCs) [e.g. soccer and football] require a muscle-tendon unit that is compliant enough to store and release the high amount of elastic energy that benefits performance in such sports. If the participants of these sports have an insufficient compliant muscle-tendon unit, the demands in energy absorption and release may rapidly exceed the capacity of the muscle-tendon unit. This may lead to an increased risk for injury of this structure. Consequently, the rationale for injury prevention in these sports is to increase the compliance of the muscle-tendon unit.Recent studies have shown that stretching programmes can significantly influence the viscosity of the tendon and make it significantly more compliant, and when a sport demands SSCs of high intensity, stretching may be important for injury prevention. This conjecture is in agreement with the available scientific clinical evidence from these types of sports activities. In contrast, when the type of sports activity contains low-intensity, or limited SSCs (e.g. jogging, cycling and swimming) there is no need for a very compliant muscle-tendon unit since most of its power generation is a consequence of active (contractile) muscle work that needs to be directly transferred (by the tendon) to the articular system to generate motion. Therefore, stretching (and thus making the tendon more compliant) may not be advantageous. This conjecture is supported by the literature, where strong evidence exists that stretching has no beneficial effect on injury prevention in these sports. If this point of view is used when examining research findings concerning stretching and injuries, the reasons for the contrasting findings in the literature are in many instances resolved.

ISSN:0112-1642    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

Urinary incontinence is defined as “the complaint of any involuntary leakage of urine” and is a common problem in the female population with prevalence rates varying between 10% and 55% in 15- to 64-year-old women. The most frequent form of urinary incontinence in women is stress urinary incontinence, defined as “involuntary leakage on effort or exertion, or on sneezing or coughing”. The aim of this article is to systematically review the literature on urinary incontinence and participation in sport and fitness activities with a special emphasis on prevalence and treatment in female elite athletes. Stress urinary incontinence is a barrier to women’s participation in sport and fitness activities and, therefore, it may be a threat to women’s health, self-esteem and well-being. The prevalence during sports among young, nulliparous elite athletes varies between 0% (golf) and 80% (trampolinists). The highest prevalence is found in sports involving high impact activities such as gymnastics, track and field, and some ball games. A ‘stiff’ and strong pelvic floor positioned at an optimal level inside the pelvis may be a crucial factor in counteracting the increases in abdominal pressure occurring during high-impact activities. There are no randomised controlled trials or reports on the effect of any treatment for stress urinary incontinence in female elite athletes. However, strength training of the pelvic floor muscles has been shown to be effective in treating stress urinary incontinence in parous females in the general population. In randomised controlled trials, reported cure rates, defined as <2g of leakage on pad tests, varied between 44% and 69%. Pelvic floor muscle training has no serious adverse effects and has been recommended as first-line treatment in the general population. Use of preventive devices such as vaginal tampons or pessaries can prevent leakage during high impact physical activity. The pelvic floor muscles need to be much stronger in elite athletes than in other women. There is a need for more basic research on pelvic floor muscle function during physical activity and the effect of pelvic floor muscle training in female elite athletes.

ISSN:0112-1642    

出版商:ADIS    

年代:2004

数据来源: ADIS

摘要:

Running economy (RE) is typically defined as the energy demand for a given velocity of submaximal running, and is determined by measuring the steady-state consumption of oxygen (V-dotO2) and the respiratory exchange ratio. Taking body mass (BM) into consideration, runners with good RE use less energy and therefore less oxygen than runners with poor RE at the same velocity. There is a strong association between RE and distance running performance, with RE being a better predictor of performance than maximal oxygen uptake (V-dotO2max) in elite runners who have a similar V-dotO2max.RE is traditionally measured by running on a treadmill in standard laboratory conditions, and, although this is not the same as overground running, it gives a good indication of how economical a runner is and how RE changes over time. In order to determine whether changes in RE are real or not, careful standardisation of footwear, time of test and nutritional status are required to limit typical error of measurement. Under controlled conditions, RE is a stable test capable of detecting relatively small changes elicited by training or other interventions. When tracking RE between or within groups it is important to account for BM. As V-dotO2during submaximal exercise does not, in general, increase linearly with BM, reporting RE with respect to the 0.75 power of BM has been recommended.A number of physiological and biomechanical factors appear to influence RE in highly trained or elite runners. These include metabolic adaptations within the muscle such as increased mitochondria and oxidative enzymes, the ability of the muscles to store and release elastic energy by increasing the stiffness of the muscles, and more efficient mechanics leading to less energy wasted on braking forces and excessive vertical oscillation.Interventions to improve RE are constantly sought after by athletes, coaches and sport scientists. Two interventions that have received recent widespread attention are strength training and altitude training. Strength training allows the muscles to utilise more elastic energy and reduce the amount of energy wasted in braking forces. Altitude exposure enhances discrete metabolic aspects of skeletal muscle, which facilitate more efficient use of oxygen.The importance of RE to successful distance running is well established, and future research should focus on identifying methods to improve RE. Interventions that are easily incorporated into an athlete’s training are desirable.

ISSN:0112-1642    

出版商:ADIS    

年代:2004

数据来源: ADIS