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At least 883 records · Page 49Linked to original sources
PubMed1998

The female athlete. The triad of disordered eating, amenorrhoea and osteoporosis.

Over the last few decades, the number of women participating in organised sports has grown dramatically. Participation in sports has led to significant health benefits for these women; however, several medical disorders have become more prevalent as the number of female athletes has increased. In response to the increase in the number of female athletes and potential medical disorders, the American College of Sports Medicine coined the term 'the female athlete triad' in 1992. The female athlete triad is a serious syndrome comprising 3 interrelated components: (i) disordered eating; (ii) amenorrhoea; and (iii) osteoporosis. The female athlete triad is a syndrome that can be prevented. Medical management of the female athlete triad requires a multidisciplinary approach, with early diagnosis and treatment being key factors. More studies are required to determine its causes, prevalence and consequences and to develop an optimal treatment strategy. All individuals, including coaches and parents, who are working with physically active girls and women should be educated about these disorders, and they should develop strategies to prevent, recognise and treat the female athlete triad.

Adolescent↗
PubMed1999

The influence of air travel on athletic performance.

Rapid transmeridian flight is a common reality for modern athletes and it has often been assumed that air travel has detrimental effects on athletic performance. The plausibility of this assumption is supported by established deteriorations in sleep and mood following transmeridian flight. However, the scientific evidence supporting the assumption is neither consistent nor compelling. Studies that have assessed athletic performance following transmeridian flight have produced mixed results and are characterised by major methodological flaws. Recent retrospective assessments of athletic team performance based on distance travelled have generally failed to indicate performance impairments following transmeridian flight. The plausibility of transmeridian air travel impairing athletic performance would be indicated by demonstration of an internally-driven circadian rhythm of athletic performance, or of deleterious performance consequences following sleep deprivation or desynchronisation between the circadian system and the environment. More rigorous research is needed to establish whether athletic performance is influenced by air travel.

Aviation↗
PubMed1999

Sports-specific adaptations and differentiation of the athlete's heart.

Although the sports-specific adaptations and differentiation of an athlete's heart (AH) were first described 100 years ago, the condition is still an area of active debate. In clinical practice, there is often an obvious lack of basic knowledge concerning the prerequisites and well established extent of the structural and functional characteristics of an AH. Some misunderstandings arise from the somewhat misleading term 'athlete's heart' because not every athlete, even if he or she is training and competing at a very high level, develops an enlarged heart. Such a condition can only be expected after years of quantitative and qualitative demanding aerobic endurance training. Although the correlation with competitive performance of endurance events is rather low in trained athletes, the relationship between heart dimensions and ergometric performance represents an important criterion for differentiation between physiological and pathological cardiac enlargement. The assessment of measures exceeding the usual clinical limits, especially concerning volume-dependent echocardiographic parameters, also requires consideration of the strong influence of anthropometric data. The existence of a concentric left ventricular hypertrophy (LVH) in strength-trained athletes is still a topic of debate in the literature, but is rejected by most recent well-conducted trials. In our review. only bodybuilders using anabolic steroids exhibited a distinctly higher hypertrophic index compared with all other groups of endurance or strength athletes. Current unsolved issues in clinical sports medicine concern the early detection of myocardial complications in athletes exercising during infectious diseases, and the eligibility for competitive sport in cases of borderline LVH.

Adaptation, Physiological↗
PubMed2000

Physiological issues surrounding the performance of adolescent athletes.

More than ever, many young athletes are being encouraged to train intensely for sporting competitions from an early age. Compared with studies in adults, less is known about the physiological trainability of adolescents. The velocity of physical growth during the adolescent years makes research with a group of young athletes particularly difficult. The purpose of this review is to discuss a number of physiological issues that surround the performances of the adolescent athlete. Research has highlighted the role of growth hormone (GH) in the abrupt acceleration of linear growth that occurs during adolescence. In addition, GH has been shown to be sensitive to exercise following short term intervention studies. The reduced anaerobic power of the adolescent athlete compared with that of an adult athlete has been attributed to the intrinsic properties of the muscle that are yet to be fully understood. Resistance training studies in male adolescents, and to a lesser extent female adolescents, highlight the substantial relative strength gains that can be obtained. Aerobic trainability in young boys appears to improve markedly during the adolescent years. One of the most plausible explanations for this observation is the 'trigger hypothesis' which links increased aerobic improvements in adolescence with hormonal changes and substantial growth of the cardiorespiratory and musculoskeletal systems. Studies of aerobic trainability in adolescent girls are too scarce to be conclusive. An understanding of the impact of long term intensive training on adolescent athletes is difficult to ascertain because physical stresses vary both between and within sports. There is, however, limited evidence to suggest that 'intense' training does not impair normal growth, development or maturation. Adolescent athletes who experience rapid growth as well as large increases in training volumes may be vulnerable to overuse injuries.

Adolescent↗
PubMed2001

Prevalence and mechanisms of development of asthma and airway hyperresponsiveness in athletes.

A high prevalence of asthma and airway hyperresponsiveness (AHR) has been reported in the athlete population. Factors potentially predisposing athletes to these conditions have not been clearly identified. Although moderate exercise has been shown to be beneficial in patients with asthma, repeated high-intensity exercise could possibly contribute to the development of asthma and AHR. This report provides an overview of the prevalence and possible mechanisms of development of asthma and AHR in the athlete population. The prevalence of asthma and AHR are higher in athletes than in the general population, particularly in swimmers and athletes performing sports in cold air environments. Possible mechanisms involved in the development of asthma in athletes are still uncertain; however, the content and physical characteristics of the inhaled air seem to be important factors, while immune and neurohumoral influences could play a modulatory role. This report stresses the need for further studies to better define the aetiologic factors and mechanisms involved in the development of asthma and AHR in athletes, and proposes relevant preventive and therapeutic measures.

Air Pollution↗
PubMed2001

Morphological evolution of athletes over the 20th century: causes and consequences.

Over the course of the past century it has become increasingly difficult to find athletes of the size and shape required to compete successfully at the highest level. Sport is Darwinian in that only the 'fittest' reach the highest level of participation. Not every physical characteristic could be expected to play a role in this selection process, but two that are important and for which substantial data assemblies exist, are height and mass. Measurements of elite athlete sizes were obtained from a variety of sources as far back as records allowed. We charted the shift in these anthropometric characteristics of elite sportspeople over time, against a backdrop of secular changes in the general population. Athletes in many sports have been getting taller and more massive over time; the rates of rise outstripping those of the secular trend. In open-ended sports, more massive players have an advantage. Larger players average longer careers and obtain greater financial rewards. In some sports it is equally difficult to find athletes small enough to compete. In contrast, there are sports that demand a narrow range of morphological characteristics. In these sports the size of the most successful athletes over the century has remained constant, despite the drift in the population characteristics from which they are drawn. A number of social factors both drive and are driven by the search for athletes of increasingly rare morphology. These include globalisation and international recruitment, greater financial and social incentives, and the use of special training methods and artificial growth stimuli. In many sports the demand for a specific range in body size reinforces the need to adopt questionable and illegal behaviours to reach the required size and shape to compete at the top level. Future scenarios also include 'gene-farming' through assortative mating and athlete gamete banks.

Biological Evolution↗
PubMed2002

Physiology of wheelchair racing in athletes with spinal cord injury.

Wheelchair racing is one of the most popular sporting activities of individuals with spinal cord injury. Athletes with this impairment have unique changes in metabolic, cardiorespiratory, neuromuscular and thermoregulatory systems, which reduce their overall physiological capacity compared with able-bodied individuals or individuals with other types of impairments. This review on spinal cord injury: presents the International Stoke Mandeville Games Federation classification of wheelchair athletes; describes methods commonly used to characterise anaerobic and aerobic fitness; presents the findings of physiological studies that have evaluated wheelchair racing performance; identifies the risks associated with temperature regulation when competing in wheelchair races; and discusses special conditions that can influence wheelchair racing performance. Currently there is limited research that has examined the relationship between sprint or distance wheelchair racing performance and the anaerobic and aerobic components of physical fitness. Although the descriptive evidence indicates that the profiles of these athletes reflect their training and participation in these specific events, the association between their physiological profiles and real or simulated racing performance is unclear. The generally accepted concept that high values of aerobic and anaerobic power are strongly correlated with endurance and sprint racing performance, respectively, are not necessarily true in this population. Athletes with spinal cord injury have an impaired thermoregulatory capacity, because the compromised autonomic and somatic nervous system functions disrupt control of skin blood flow and sweating below the level of the lesion. As a result, they may be more susceptible to hyperthermia during distance wheelchair racing performance. Wheelchair athletes should follow recommendations advocated for able-bodied individuals to minimise their risks of heat stress during competition. Many athletes with quadriplegia voluntarily induce autonomic dysreflexia (commonly known as boosting) during distance racing events to improve performance. Experimental evidence indicates that boosting can improve performance time by 10% in elite wheelchair marathon racers during simulated racing, as a result of increased oxygen utilisation in the boosted state. However, since boosting can be dangerous to health, the International Paralympic Committee has banned athletes from voluntarily inducing it during competition. The use of anti-gravity suits to increase lower-body positive pressure can increase the peak oxygen uptake, cardiac output and stroke volume. However, the use of abdominal binders does not influence these physiological responses. An effect of either of these techniques on wheelchair racing performance has not been demonstrated.

Body Temperature Regulation↗
PubMed2004

The cardiovascular effects of chronic hypoestrogenism in amenorrhoeic athletes: a critical review.

In premenopausal women, the most severe menstrual dysfunction is amenorrhoea, which is associated with chronic hypoestrogenism. In postmenopausal women, hypoestrogenism is associated with a number of clinical sequelae related to cardiovascular health. A cardioprotective effect of endogenous oestrogen is widely supported, yet recent studies demonstrate a deleterious effect of hormone replacement therapy for cardiovascular health. What remain less clear are the implications of persistently low oestrogen levels in much younger amenorrhoeic athletes. The incidence of amenorrhoea among athletes is much greater than that observed among sedentary women. Recent data in amenorrhoeic athletes demonstrate impaired endothelial function, elevated low- and high-density lipoprotein levels, reduced circulating nitrates and nitrites, and increased susceptibility to lipid peroxidation. Predictive serum markers of cardiovascular health, such as homocysteine and C-reactive protein, have not yet been assessed in amenorrhoeic athletes, but are reportedly elevated in postmenopausal women. The independent and combined effects of chronic hypoestrogenism and exercise, together with subclinical dietary behaviours typically observed in amenorrhoeic athletes, warrants closer examination. Although no longitudinal studies exist, the altered vascular health outcomes reported in amenorrhoeic athletes are suggestive of increased risk for premature cardiovascular disease. Future research should focus on the presentation and progression of these adverse cardiovascular parameters in physically active women and athletes with hypoestrogenism to determine their effects on long-term health.

Adult↗
PubMed2006

Eating disorders in the male athlete.

Eating disorders do occur in male athletes. They are less prominent than in female athletes, and therefore in danger of being missed. The high-risk sports fall into the same categories as with females: aesthetic sports, sports in which low body fat is advantageous, such as cross-country and marathon running, and sports in which there is a need to "make weight", including wrestling and horse racing. Athletic involvement may foster the development of an eating disorder. Some male athletes, in their preoccupation with body image, will abuse anabolic steroids. While sports participation may contribute to the aetiology of an eating disorder, the converse is also true. Exercise may be used as therapy for some cases of eating disorder. In order to adequately treat eating disorders in the male athlete, it is first essential to identify cases. Psychoeducation of athletes, their families, coaches and trainers is an important first step. Counselling an athlete to pursue a sport appropriate to his body type, or to leave his sport behind altogether (an unpopular recommendation from a coach's perspective) can be important to treatment. Treatment of co-morbid psychiatric conditions is essential. Treatment can be structured using a biopsychosocial approach, and all appropriate modalities of therapy, including individual, family and group, as well as psychopharmacotherapy, where appropriate, should be applied.

Feeding and Eating Disorders↗
PubMed2006

Vegetarian diets : nutritional considerations for athletes.

The quality of vegetarian diets to meet nutritional needs and support peak performance among athletes continues to be questioned. Appropriately planned vegetarian diets can provide sufficient energy and an appropriate range of carbohydrate, fat and protein intakes to support performance and health. The acceptable macronutrient distribution ranges for carbohydrate, fat and protein of 45-65%, 20-35% and 10-35%, respectively, are appropriate for vegetarian and non-vegetarian athletes alike, especially those who perform endurance events. Vegetarian athletes can meet their protein needs from predominantly or exclusively plant-based sources when a variety of these foods are consumed daily and energy intake is adequate. Muscle creatine stores are lower in vegetarians than non-vegetarians. Creatine supplementation provides ergogenic responses in both vegetarian and non-vegetarian athletes, with limited data supporting greater ergogenic effects on lean body mass accretion and work performance for vegetarians. The potential adverse effect of a vegetarian diet on iron status is based on the bioavailability of iron from plant foods rather than the amount of total iron present in the diet. Vegetarian and non-vegetarian athletes alike must consume sufficient iron to prevent deficiency, which will adversely affect performance. Other nutrients of concern for vegetarian athletes include zinc, vitamin B12 (cyanocobalamin), vitamin D (cholecalciferol) and calcium. The main sources of these nutrients are animal products; however, they can be found in many food sources suitable for vegetarians, including fortified soy milk and whole grain cereals. Vegetarians have higher antioxidant status for vitamin C (ascorbic acid), vitamin E (tocopherol), and beta-carotene than omnivores, which might help reduce exercise-induced oxidative stress. Research is needed comparing antioxidant defences in vegetarian and non-vegetarian athletes.

Antioxidants↗
PubMed1995

Assessment of training-induced autonomic adaptations in athletes with spectral analysis of cardiovascular variability signals.

The purpose of this study was to assess the adaptive effects of endurance training on autonomic functions in athletes with spectral analysis of cardiovascular variability signals. Continuous ECG, arterial blood pressure (ABP), and respiratory signals were recorded from 15 athletes (VO2max > 55 ml/(kg.min)) and 15 nonathletes (VO2max < 45 ml/(kg.min)) in the sitting position during controlled respiration (tidal volume 700 ml and 15 cycles/min). The autonomic functions were assessed by the normalized low-frequency power (LF power: 0.06-0.14 Hz) and high-frequency power (HF power: the region of the respiratory frequency based on respiratory spectrum) obtained from the autospectra of the RR interval, systolic arterial pressure (SAP), and diastolic arterial pressure (DAP) variability signals. The spontaneous baroreflex sensitivity (BRS) was evaluated by the moduli, BRSLF and BRSHF, of the transfer function between the RR interval and SAP variability in LF and HF bands. The resting HR in athletes was significantly lower than that in nonathletes. In the case of RR interval spectra, the HF power was significantly higher in athletes than in nonathletes, whereas the LF power was significantly lower in athletes than in nonahtletes. These differences might reflect an alteration of sympathovagal interaction with a predominance of parasympathetic activity. However, there was no significant difference in the LF power of SAP and DAP autospectra, reflecting the sympathetic vascular control. The BRSLF and BRSHF were significantly higher in athletes as compared with nonathletes. These results indicate that endurance training induces autonomic imbalance (i.e., the enhanced vagal activities/the attenuated sympathetic tone), which may in part contribute to the resting bradycardia and an increase in the spontaneous BRS in athletes.

Adaptation, Physiological↗
PubMed2000

Exploring competitive orientation in a group of athletes participating in the 1996 paralympic trials.

The purposes of this study were to test (1) whether athletes with congenital disabilities exhibited different competitive orientations than athletes with disabilities acquired during their lifespans and (2) whether male athletes with disabilities exhibited different competitive orientations than their female peers. 54 paraplegic, quadriplegic and amputee athletes competing in the 1996 Paralympic Track and Field Trials completed the Sport Orientation Questionnaire. No mean differences were found between men and women, athletes with different onsets of their disabilities across the lifespan, between adolescents and adults, and between athletes with different severity classifications on the Goal orientation, Competitiveness, and Desire to win scales. Larger studies are encouraged to examine competitive orientation, as well as scores on tests specifically constructed to be administered to athletes with disabilities.

Adolescent↗
PubMed1998

Sports-medical assessment for athletes with a disability.

The purpose of this article is to describe a Sports-Medical Assessment Protocol (SMAP) for athletes with a disability. The purposes of the SMAP are to identify medical problems and therapeutic goals for supplementary training programmes for athletes with a disability, and to provide baseline data for future follow up. The SMAP includes an interview, cardiorespiratory assessment and physical and functional examination. Data were collected from assessment protocols of 14 male athletes with various neurological disorders who qualified to participate in the Atlanta Paralympic Games in 1996. Nine of the athletes had some range of motion (ROM) limitations, one had shoulder pain and one low back pain following physical stress. Two athletes with postpolio presented muscle fasciculation and one of them also presented bilateral Carpal Tunnel Syndrome. Based on the results we concluded that utilizing the SMAP may contribute to trainers' and athletes' (with a disability) awareness of the physical needs of elite athletes as well as participants in leisure sport activities.

Adult↗
PubMed1999

Naturalistic observation of athletic drug-use patterns and behavior in professional-caliber bodybuilders.

Athletic performance-enhancing drug use is widespread. Awareness in the medical community lags because various athletic subcultures have not been penetrated by conventional medical literature. This report presents a current and comprehensive assessment of drugs used by professional-caliber bodybuilders to enhance athletic performance. The scale of drug use documented significantly exceeds all previous reports from athletic populations and indicates that this group is at significant risk for use. Drug-use patterns and behavior encompass multiple domestic, foreign, and veterinary agents to create "successful" training programs. The presence of interathlete and intersport communication at amateur and professional levels creates a wide application for this information in athletic settings. Since use may not be limited to the competitive athlete, a heightened awareness will aid practitioners in correlating clinical observations with accurate athletic drug-use information.

Adult↗
PubMed2001

Caffeine as a lipolytic food component increases endurance performance in rats and athletes.

Caffeine is one of the famous ergogenic aids in the athletic field. Caffeine has been known to stimulate lipolysis that spares stored glycogen utilization during moderate intensity exercise. Therefore, we investigated the effects of caffeine ingestion on exercise performance in rats and athletes. Rats were administered the caffeine (6 mg/kg) 1 h prior to the exercise then were run on a treadmill at a speed of 20 m/min. They were decapitated at 0 min, 30 min, 60 min of exercise, and exhausted time point. Human subjects ingested the caffeine (5 mg/kg) 1 h prior to the exercise. They exercised on a cycle ergometer at 60% of their VO2max for 45 min, and then the exercise intensity was increased to 80% of their VO2max until exhaustion. Blood and breathing gas samples were collected and calculated every 10 min during exercise. Respiratory exchange ratio of the caffeine trial was significantly lower than that of the placebo trial in the athletes' study (p<0.05). Blood free fatty acid (FFA) levels in studies of both rats and athletes were increased by caffeine ingestion during exercise (p<0.05). Blood lactate levels were also increased during exercise in both rats and athletes (p<0.05). Increased FFA and glycerol concentrations reduced glycogen utilization during exercise compared with placebo group in rats. In addition, endurance time to exhaustion was significantly increased by the caffeine ingestion in both rats and athletes (p<0.05). These results suggest that the caffeine ingestion enhanced endurance performance resulting from spare stored glycogen with increasing lipolysis from adipose tissues and fat oxidation during exercise both in rats and in athletes.

Adipose Tissue↗
PubMed2000

Creatine use among a select population of high school athletes.

OBJECTIVE: To determine the prevalence, frequency, and patterns of creatine use among a local population of high school athletes. SUBJECTS AND METHODS: Male and female high school athletes completed an anonymous questionnaire on creatine use during the August 1999 preparticipation examinations at a single institutional sports medicine center. RESULTS: A total of 328 students (182 males and 146 females) aged 14 to 18 years (mean +/- SD 15.2 +/- 1.3 years) completed the survey (100% response rate), although not all athletes answered each question. Twenty-seven athletes (8.2% of total group), 1 of whom was female, reported creatine use. Of these 27 athletes, 14 (52%) were taking creatine at the time of the survey. The frequency of creatine use among past and current users was equally distributed among rarely (30%), weekly (35%), and daily (35%). Creatine users were older than nonusers (mean 16.5 +/- 1.2 vs 15.0 +/- 1.3 years; P < .001). Of creatine users, 21 (78%) were male football players. Nineteen of 24 respondents (79%) believed creatine improved their performance. Overall, 78% of users either did not know how much creatine they were taking (12/22 respondents) or were taking greater than the recommended doses (5/22 respondents). Minor gastrointestinal side effects or muscle cramps were reported by 5 (20%) of 25 respondents. Creatine users were more likely than nonusers to know other creatine users (81% vs 22%; P < .001) and to use other supplements (67% vs 9%; P < .001). Creatine users obtained creatine information primarily from friends (74%) and purchased creatine predominantly from health food stores (86%). CONCLUSIONS: High school male and female athletes as young as 14 years use creatine. Of high school athletes participating in our study, 8.2% reported creatine use. Relatively minor side effects, diarrhea, cramps, and loss of appetite, were reported. Creatine users seem to believe that creatine improves their performance, but they may lack sufficient information to make informed decisions regarding creatine use. Further larger scale study is warranted.

Adolescent↗
PubMed1975

Comparative left ventricular dimensions in trained athletes.

Little is known about the structure of athletes' hearts of anatomic variations associated with training. Echocardiograms of 56 active athletes were obtained. Mean left ventricular end-diastolic volume and mass were increased in athletes involved in isotonic exercise, such as swimming (181 ml, 308 g) and running (160 ml, 302 g), compared with controls (101 ml, 211 g); wall thickness was normal (less than or equal to 12 mm). Athletes involved in isometric exercise, such as werstling and shot putting, had normal mean left ventricular end-diastolic volumes (110 ml, 122 ml), but increased wall thickness (13 to 14 mm) and mass (330 g, 348 g). Thus, athletes participating in isotonic exercise had increased left ventricular mass with cardiac changes similar to those in chronic volume overloads. Athletes participating in isometric exercise had increased left ventricular mass with cardiac changes similar to those in chronic pressure loads, recognizing greater left ventricular mass and volume in well-trained athletes aids in interpreting values deviating from "normal" limits.

Adolescent↗
PubMed1999

Drug testing in elite athletes--the Israeli perspective.

BACKGROUND: The use of performance-enhancing drugs by athletes, in particular anabolic steroids, is probably one of the major problems in sports today. During the early 1990s the Israeli Sports Federation and Olympic Committee established the Israeli Sports Anti-Doping Committee. OBJECTIVES: To present a follow-up on tests for use of performance-enhancing drugs among elite Israeli athletes from 1993 until the present. METHODS: Since 1993, 273 drug tests (urine samples) were performed in elite Israeli athletes. These tests were done during major competitions, and at random during the regular training season without prior notice to the athletes. The urine samples were sent for analysis to an official drug laboratory of the Olympic Committee in Cologne, Germany. RESULTS: Since 1993, seven (2.7%) male Israeli elite athletes (5 weight lifters, a javelin thrower, and a sprinter) tested positive for performance-enhancing drugs--all of them for anabolic steroids, and two for diuretics as well. DISCUSSION: These findings suggest that the phenomenon of performance-enhancing drug use by elite athletes has also entered Israeli sports, and probably represent the tip of the iceberg among Israeli sportsmen. Therefore, more drug tests should be performed, especially at random without prior notice and during the regular season. Athletes in the most popular sports such as soccer and basketball should also be tested. The concern over the use of these agents is both medical and ethical.

Anabolic Agents↗