Medicine and sport science最新文献

Climbing and mountaineering sports are gaining more and more public interest. This chapter reviews scientific studies on injuries and accidents in climbing and mountaineering sports to evaluate the danger of these sports and their specific injuries and preventive measures. An initial PubMed query was performed using the key words 'rock climbing', 'sport climbing', 'mountaineering', 'alpine injuries' and 'climbing injuries'. More than 500 extracted papers were analyzed which gave information on injury, mortality/fatality, prevention and risk factors. Cross-references were also scanned according to the above given criteria. Also the data sources of the UIAA and IFSC Medical Commissions were analyzed. Overall, alpine (traditional) climbing has a higher injury risk than sport climbing, especially indoor climbing. Alpine and ice climbing have more objective dangers which can affect climber safety. Overall injury rates are low, nevertheless fatalities do occur in all climbing disciplines. Altitude-related illnesses/injuries also occur in mountaineering. Most injuries in sport climbing are overstrain injuries of the upper extremity. In alpine climbing, injuries mostly occur through falls which affect the lower extremity. Objective reporting of the injury site and severity varied in most studies according to the injury definition and methodology used. This creates differences in the injury and fatality results and conclusions, which in turn makes inter-study comparisons difficult. In future studies, the UIAA MedCom score for mountain injuries should be used to guarantee inter-study comparability. Evidence in preventive measures is low and further studies must be performed in this field.

The objective of this review was to summarize the epidemiological literature for surfboard riding (surfing), kite surfing and personal watercraft (PWC) riding injuries and describe the incidence and nature of these injuries, common risk factors, and strategies for prevention. The databases searched for relevant publications included Medline, ScienceDirect, ProQuest International, PubMed, Academic Search Premier as well as Google Scholar to identify additional, non-indexed studies. Overall, there was a lack of good quality descriptive studies for these three sports and many of the studies reviewed involved the use of administrative datasets or case-series designs. Among the few studies to provide incidence estimates, there were inconsistencies in how injury was defined, the inclusion criteria, and the reporting of incidence rates, making comparisons within and between the sports difficult. While the reported incidence rates were generally low, head and lower extremity injuries were common across all three sports. Only two studies reported evidence for postulated risk factors. Bigger waves and surfing over rock or reef sea floor increased the risk of injury among competitive surfers, while older age and having more experience increased the risk of significant injuries among recreational surfers. No evaluations of preventative measures were identified. This review demonstrates the need for well-designed epidemiological research, especially studies that focus on the accurate measurement and description of incidence, nature, severity and circumstances of injuries. Once this has occurred, interventions targeted at reducing the incidence of injuries among these sports can be designed, implemented and evaluated.

Resistance exercise (RE) preceding the provision of high-quality dairy protein supports muscle anabolism. Milk contains bioactive components, including two high-quality protein fractions, calcium and vitamin D, each of which has been shown modulate body composition (increasing lean mass and decreasing fat mass) under energy balance and hypoenergetic conditions. These dairy nutrients are also essential for skeletal health. Acutely, no study of RE and milk/whey consumption has been undertaken exclusively in female athletes, let alone women, nevertheless, studies with both men and women show increased lean mass accretion following milk/whey compared to soy/placebo. Currently, no longer-term RE studies with milk supplementation have been done in female athletes. However, trials in young recreationally active women demonstrated augmented increases in lean mass and decreases in fat mass with RE and milk or whey protein consumption. The amount of protein consumed post-exercise is also important; two trials using yogurt (5 g protein/6 oz) failed to demonstrate a positive change in body composition compared to placebo. For bone health, RE plus dairy improved bone mineral density at clinically important sites and reduced bone resorption. With energy restriction, in one study, higher dairy plus higher protein resulted in greater fat loss, lean mass gain and improved bone health in overweight women. In another study, milk and calcium supplementation showed no greater benefit. Neither trial exclusively utilized RE. Overall, RE and milk/dairy consumption positively impact body composition in women by promoting losses in fat, gains or maintenance of lean mass and preservation of bone. Future studies in female athletes and under energy restriction with RE alone are warranted.

Strenuous and/or prolonged exercise causes transient perturbations in immune function. It is well accepted that this is one mechanism contributing to the higher occurrence of infection (e.g. upper respiratory tract infection (URTI)) in athletes, especially endurance athletes. URTI or upper respiratory tract (URT) symptoms can negatively affect training and competition performance but athletes must train intensively to be successful. Therefore, interventions that can legitimately enhance immune function and reduce URTI risk can be of benefit to athletes. Bovine colostrum supplementation has been investigated as a possible nutritional countermeasure to enhance (or maintain) immune function, and reduce URTI risk, following strenuous or prolonged exercise and during intensive training periods. There is convincing evidence that daily supplementation with bovine colostrum, for a number of weeks (and preliminary evidence for acute effects after a single dose), can maintain intestinal barrier integrity, immune function and reduce the chances of suffering URTI or URT symptoms in athletes or those undertaking heavy training. The mechanisms are not fully understood at present but there is preliminary evidence suggesting that the effects on immune function are attributable, at least in part, to small bioactive components that survive digestion and are biologically available after consumption, but further work is required. In summary, the balance of existing evidence does support the notion that bovine colostrum is beneficial for certain groups of athletes, such as those involved in strenuous training (e.g. endurance athletes), in terms of immunity and resistance to infection.

Sweat is produced during exercise to help dissipate some of the extra heat produced due to an increase in metabolic rate. Inadequate drink ingestion during exercise means athletes finish exercise hypohydrated and when the time between exercise bouts is short, effective rehydration strategies will be necessary to prevent subsequent performance impairment. For complete rehydration, drink volume must be sufficient to replace sweat losses as well as the additional water losses during recovery. Once a sufficient volume of drink is ingested it is the drink composition that dictates the rehydration success of the drink. It is well known that addition of sodium and some other nutrients to rehydration drinks enhances fluid balance restoration after exercise, but the effects of milk proteins have been less well documented. Skimmed milk is an effective post-exercise rehydration solution and enhances the restoration of fluid balance after exercise-induced dehydration to a greater extent than a carbohydrate-electrolyte sports drink. Whilst there are a number of factors in skimmed milk that might be responsible for this enhancement of rehydration, it appears that some of the effect is due to the milk protein, as milk protein has been shown to be more effective for post-exercise rehydration than an isoenergetic amount of carbohydrate. Whilst the effects of whey protein on post-exercise rehydration are equivocal, whey protein addition to a carbohydrate-electrolyte rehydration solution certainly does not impair rehydration. Therefore, in situations where protein ingestion after exercise might be advantageous for the athlete, this protein might also enhance restoration of fluid balance.

Rotator cuff disease is among the most common musculoskeletal disorders with high direct and indirect costs in industrialized countries. Not all rotator cuff tears are symptomatic. Genetics has recently been investigated as a factor involved in the pathogenesis of rotator cuff pathology. Genetic factors seem to be involved in symptom presentation and tear progression. As rotator cuff disease is multifactorial, no single gene is directly involved in the pathology. Phenotypic expression of genetic susceptibility manifests at the level of ultrastructure of the tendon. Predisposing genes may also operate through apoptosis and regenerative capacity. Studies on cellular and molecular biology are more numerous, but still incomplete, and recently have focussed on the role of apoptosis in tendinopathy, analyzing its key mediators and cellular changes. Oxidative stress is responsible for reduction of collagen synthesis. Biological investigations have identified recently new risk factors. Preliminary reports introduced the possible role of glucose as a risk factor for rotator cuff tear. Further studies are required to fully clarify the genetic and biological factors involved in rotator cuff tears.

The secretion of growth hormone (GH) is regulated through a complex neuroendocrine control system, especially by the functional interplay of two hypothalamic hormones, GH-releasing hormone and somatostatin. These hormones are subject to modulation by a host of neurotransmitters and are the final mediators of endocrine and neural influences for GH secretion. Interest in the possible role of γ-aminobutyric acid (GABA) in the control of GH secretion began decades ago. However, interest in its role as an ergogenic aid is only recent. It is well accepted that GABAergic neurons are found in the hypothalamus and recent evidence suggests its secretion within the pituitary itself. Inhibition of GABA degradation and blockade of GABA transmission as well as administration of GABA and GABA mimetic drugs have all been shown to affect GH secretion. However, there are many controversial findings. The effects may depend on the site of action within the hypothalamic-pituitary unit and the hormonal milieu. Experimental and clinical evidence support the presence of a dual action of GABA - one mediated centrally, the other exerted directly at the pituitary level. The two sites of action may be responsible for excitatory and inhibitory effects of GABA on GH secretion. This chapter will outline the anatomical basis for possible influences of GABA on GH secretion and present evidence for a role of GABA in the control of GH release by actions at either hypothalamic or pituitary sites. The potential ergogenic benefits of oral GABA supplementation will also be discussed.

Prolonged and high-intensity exercise affects immune function and leads to an increased risk of upper respiratory tract infections (URTIs) in endurance athletes. The increased incidence of URTI symptoms may negatively affect athletic performance. Various nutritional supplements have been tested in the last decade for their ability to prevent developing of URTIs or reduce their incidence. One of the most promising nutritional supplements is β-glucan, a well-known immunomodulator with positive effects on functioning of immunocompetent cells. However, β-glucans are a diverse group of molecules that vary in macromolecular structure, solubility, viscosity, molecular weight and biological activity. This fact is supported by results from recent human clinical studies where β-glucans of different origin and properties differed in ability to prevent or reduce incidence of URTIs in athletes. It has been found that pleuran, a unique insoluble β-glucan isolated from mushroom Pleurotus ostreatus, significantly reduced the incidence of URTI symptoms in athletes. In addition, it was able to increase the number of circulating natural killer cells and to prevent reduction of natural killer cell activity. Contrarily, soluble oat β-glucan supplementation did not alter URTI incidence in endurance athletes. This difference suggests that the immunomodulatory capacity of β-glucans is strongly dependent on solubility and structural factors such as backbone structure and degree of branching. This review refers to using pleuran as a natural supplement that is able to protect endurance athletes against development of URTI.

The aquatic environment is a complex mix of waterways with varying uses and hazards. It is the intersection of the use of the water and the hazards which provides enjoyment to those who use them as well as risk to a person's health. Canoeing, kayaking and rafting have and continue to be popular recreation sports in aquatic environments. This chapter explores participation in, risks associated with and prevention strategies for keeping canoeists, kayakers and rafters safe and healthy. There is a dearth of good quality descriptive studies exploring these issues, particularly around the risks involved and the effectiveness of proposed prevention strategies. According to Outdoor Foundation, there are 23.9 million people in the USA who undertake paddling activities per annum, with canoeing (10.1 million) being the most popular activity followed by recreational kayaking (6.2 million). There were 141 deaths of canoeists (89) and kayakers (52) identified by the US Coast Guard in their recreational boating statistics data for 2009. The crude rate of death per 100,000 participants for canoeing ranges between 0.72 and 0.92 and for kayaking between 0.37 and 0.41 per annum. Although death is the most severe consequence of a misadventure while paddling, there are a range of other hazards faced such as hitting objects, waterborne diseases, hypothermia from unintended submersion, blisters, muscle strain, cuts and abrasions. There are a range of prevention strategies which have been proposed and provided in this chapter. However, there is very little evidence of their effectiveness. Further research is required in understanding the risk associated with paddling activities, the effectiveness of prevention strategies and how these strategies might be delivered.