Hematological indices and iron status in athletes of various sports and performances

PURPOSE: Alterations of the red blood cell system and iron metabolism can influence physical performance. On the other hand, exercise can influence hematological variables. The purpose of this epidemiological study was to investigate the characteristics of the red blood cell system and the iron metabolism in athletes of different sporting disciplines and at different levels of performance. METHODS: We studied 851 male subjects (747 athletes, 104 untrained controls). Hemoglobin (Hb), hematocrit (Hct), red blood cell count (RBC), iron, transferrin, ferritin (Fer), and haptoglobin were analyzed in standardized blood samples, obtained after 2 d of rest, considering levels of performance (internationally, nationally, locally competitive, and leisure time), distinctive sporting category (endurance- (END), strength- (POW), and mixed-trained (MIX)), and, within endurance athletes, distinctive disciplines (cycling (CYC) and running (RUN)). RESULTS: No difference was found between athletes and controls in Hb and Hct. Reduced Hb, Hct, and RBC levels were observed in END compared with POW and MIX. These findings can mainly be attributed to exercise-induced plasma volume expansion, and only to a lesser degree and in selected athlete populations to hemolysis, as low haptoglobin is only observed in RUN, not in CYC, suggesting that not exercise itself but the "traumatic" movement of running might trigger the destruction of red blood cells. Physical activity of increasing duration and workloads (leisure time compared with competitive athletes) leads to decreased Fer levels in athletes, disregarding their discipline, but more pronounced in RUN. CONCLUSION: Physical training itself has no significant effect on selected hematological variables in athletes compared with untrained controls. The specific type and duration of exercise is of major importance in the adaptations of the blood cell system and the iron metabolism.     

Antioxidant status of interval-trained athletes in various sports

Muscular exercise results in an increased production of free radicals and other forms of reactive oxygen species (ROS). Further, developing evidence implicates cytotoxins as an underlying etiology of exercise-induced stimuli in muscle redox status, which could result in muscle fatigue and/or injury. Two major classes of endogenous protective mechanisms (enzymatic and nonenzymatic antioxidants) work together to reduce the harmful effects of oxidants in the cell. This study examined the effects of acute physical exercise on the enzymatic antioxidant systems of different athletes and comparison was made to the mechanism of action of three main antioxidant enzymes in the blood. Handball players (n = 6), water-polo players (n = 20), hockey players (n = 22), basketball players (n = 24), and a sedentary control group (n = 10 female and n = 9 male) served as the subjects of this study. The athletes were divided into two groups according to the observed changes of activity of superoxide dismutase enzyme. The antioxidant enzyme systems were characterized by catalase (CAT), glutathione-peroxidase (GPX), and superoxide-dismutase (SOD) and measured by spectrophotometry. An important finding in the present investigation is that when the activities of SOD increased, the activities of GPX and CAT increased also and this finding related to the physical status of interval-trained athletes. Positive correlation between SOD and GPX activities was observed (r = 0.38 females, r = 0.56 males; p < 0.05). We have observed that the changes in the primary antioxidant enzyme systems of athletes are sport specific, and different from control subjects. Presumably, with interval-trained athletes, hydrogen-peroxide is significantly eliminated by glutathione-peroxidase. From these results it can be concluded that the blood redox status should be taken into consideration when establishing a fitness level for individual athletes.     

Scale of protection and the various types of sports mouthguard

Objectives: To present a grading system of the protection offered by various types of mouthguard, together with an indication of associated risks, in order to make athletes aware of the consequences of improper or no mouth protection.

Methods: A review of the literature on mouthguards, mouthguard materials, and novel laminates for mouthguards was carried out as it was apparent that information on mouthguards was lacking. Studies on stock (or unfitted) mouthguards, mouth formed (boil and bite) mouthguards, and custom mouthguards are reviewed.

Results: A scale of protection offered by various mouthguards and novel laminates has been produced, where 0 indicates no mouthguard and 10 indicates a custom made mouthguard offering excellent protection.

Conclusions: From work carried out on laminates and the manufacturing processes of mouthguards, it became apparent that information was lacking to enable athletes make informed decisions about the best oral protection for their chosen sport.

     

Evaluation of the strength-size relationship in vivo using various muscle size indices

PURPOSE: It is well accepted that maximum strength is related to muscle size. The primary purpose of this study was to determine whether anthropometric or dual-energy x-ray absorptiometry (DEXA) estimates of muscle size were valid predictors of plantar flexor maximum voluntary contraction (MVC) strength and could be used in lieu of more sophisticated techniques (e.g., magnetic resonance imaging (MRI)). Additionally, we compared the relationship among MVC and three MRI-determined muscle size measures; anatomical (ACSA) and physiological (PCSA) cross-sectional areas; and muscle volume (VOLm). METHODS: We measured plantar flexor MVC at 1.83 rad and various indices of muscle size: 1) body weight, 2) total body lean mass (LM) (DEXA), 3) lower leg LM (DEXA), 4) lower leg circumference, 5) estimated muscle+bone cross-sectional area (CSA) from circumference and calf skin-fold, 6) triceps surae ACSA, 7) triceps surae PCSA, and (8) triceps surae volume (VOLm), in 39 premenopausal women (mean +/- SD: 36 +/- 8 yr, 165 +/- 6 cm, and 65 +/- 9 kg). RESULTS: Zero-order correlations showed significant (P < 0.05) associations between MVC and total body LM (r = 0.365), lower leg LM (r = 0.381), circumference (r = 0.584), estimated muscle+bone CSA (r = 0.447), ACSA (r = 0.733), PCSA (r = 0.715), and VOLm (r = 0.649). By using the Fisher Z-transformation, ACSA and PCSA correlated significantly higher with MVC (P < 0.05) than anthropometric and DEXA indices. Further, only ACSA and PCSA regressed to the origin, indicating the ability to predict MVC was greatest with these two measures. CONCLUSIONS: The MRI-determined muscle size indices, which were specific to the triceps surae, correlated with strength better than whole limb anthropometric and DEXA indices. In this group of women, both ACSA and PCSA appeared superior to VOLm for predicting strength. PCSA was not found to be more precise than ACSA. ACSA appears to provide adequate precision for estimating plantar flexor specific tension in vivo.     

Specialization patterns across various youth sports and relationship to injury risk

Objectives: Current trends among young athletes towards earlier specialization age and year-round training on multiple teams has raised concern for increased injury risk. Our previous analyses showed higher risk for injury in highly specialized young athletes. The goal of this research was to determine whether sports specialization and injury patterns vary by sports type.

Methods: In this clinical case-control study, injured athletes (aged 7–18 years) were recruited from sports medicine clinics and compared to similarly aged uninjured athletes recruited from primary care clinics. Participants completed a survey reporting age, gender, sport type, specialization patterns, and details regarding sports-related injuries in the previous 6 months. Clinical diagnoses were collected from patients’ medical records. Injuries were classified as acute, overuse, or serious overuse.

Results: Of 1,190 athletes enrolled, 26% (313) were single-sport specialized (reported participation in one sport and trained >8 months/year). Sports with the highest proportion of single-sport specialized athletes were tennis (46.7%), gymnastics (30.1%), and dance (26.3%). Single-sport specialized athletes in individual sports started specializing at a younger age (11.2 ± 2.4 vs. 12.0 ± 2.7, p = 0.05) and reported higher training volumes (11.8 vs. 10.3 h/week, p = 0.04) than those in team sports. Sports with the youngest specialization age were gymnastics (8.9 ± 1.7), dance (10.8 ± 3.0), and soccer (10.9 ± 2.4). Single-sport specialized athletes in individual sports accounted for a higher proportion of overuse injuries (44.3% vs 32.2%, OR = 1.67, p = 0.037) and serious overuse injuries (23.4% vs 11.6%, OR = 2.38, p = 0.011), but a lower proportion of acute injuries (28.8% vs 13.8%, OR = 0.37, p = 0.001) compared to single-sport specialized athletes involved in team sports.

Conclusions: Athletes in individual sports may be more likely to specialize in a single sport than team sport athletes. Single-sport specialized athletes in individual sports also reported higher training volumes and greater rates of overuse injuries than single-sport specialized athletes in team sports.     

Effect of prolonged storage on various indices of the fatty components of freeze-dried products

The effect of prolonged storage at the temperature 20 +/- 5 degrees C and relative humidity 70-80% on the freeze-dried food products packed in a three-layer polymer was investigated. The organoleptic parameters, fat content and fat physicochemical properties were determined in the freshly prepared foods and foods stored for 6, 10 and 14 months. The fat component of cereals and vegetables was found to change during storage: the acid and peroxide numbers increased, products of secondary oxidation accumulated, and non-saturated fatty acids decreased. Among the foodstuffs examined the buckwheat cereal and mashed potatoes proved to be most stable and edible after 14 months of storage.     

Fractures in sports

This study reports the epidemiology of fractures a sports in Denmark. The ata are based on patients seen in casualty wards with a catchment area of 3% of the population in a 2-year registration period. A total of 4572 fractures were registered among the 26,347 sport injuries seen. Fractures among soccer players were most frequent, but motorcycle sport had the highest fracture incidence. The upper extremities suffered 62% of all fractures. Nine percent of the patients had to be admitted to hospital. Seventy-two percent of the patients needed further contact with the health system after the primary treatment in the casualty ward.     

Emergencies in sports

Activity can cause or exacerbate certain skin conditions. Sweaty skin is a warm, moist environment for fungi and yeasts, and sports participation may transmit or worsen a viral condition such as herpes simplex. Specialized medication regimens and topical treatments can sometimes prevent a flare-up or minimize activity interruptions.     

Emergencies in sports

Sports-related acute nail trauma brief can cause subungual hematoma and pain, which can be alleviated by fluid evacuation; the differential diagnosis includes subungual melanoma. A careful history will help distinguish splinter hemorrhages related to systemic disease from those caused by trauma. Chronic trauma can damage the nail matrix, leading to longitudinal splits or ridging, pigmentary changes, pterygium, or dystrophy. Mildly ingrown toenails can be treated with cotton placed under the lateral nail edges and proper trimming; severe cases may require surgery. Treatment of acute paronychia includes systemic antibiotics, while chronic paronychia may require topical or systemic antifungal agents.     

Emergencies in sports

Groin injury is common in sports that involve high-speed torsion of the trunk, especially soccer, as in this case of a 28-year-old goalie. The sports hernia, a syndrome of pain caused by disruption of the inguinal canal without a clinically detectable hernia, is often initially overlooked. Examination reveals maximal tenderness over the pubic tubercle and posterior inguinal canal. The diagnosis is clinical, but x-rays and bone scanning may help rule out a concurrent injury. The pain may be multifactorial, with coexisting hip or adductor muscle pathology complicating the clinical picture. Rehabilitation, particularly core strengthening with emphasis on the abdominal obliques, is the first line of treatment. If this is ineffective, surgery is usually successful, and most athletes return to a high level of sports participation 6 to 8 weeks postsurgery.     

Emergencies in sports

‘Highlights’ offers readers practical information gleaned from recent medical literature and meetings.     

From sports injury prevention to safety promotion in sports

Every fifth unintentional injury treated at a healthcare facility in the industrialised part of the world is associated with sports or physical exercise. This article reviews the literature regarding the theoretical and practical underpinnings for community-based sports safety promotion, including both professional and recreational sports. While injury prevention entails the implementation of specific interventions in terms of structural or educational measures, sports safety promotion includes also the antecedent and wider campaigns that are required to succeed with these measures. Comprehensive sports safety promotion programmes thus require that the perspective on the sports injury problem is made broader than consideration of the individual athlete. The results display that involvement in sports safety issues from the sports federations that formulate policies and allocate resources is necessary for coordinated implementation of programme actions. The authorities responsible for sports facilities and legislations in the civil society also need to be included, because of the fact that they control many of the central safety determinants in the sporting environment. It is concluded that the sports injury problem needs to be addressed in liaison with the leaders of socially defined sports communities and the governments representing geographically defined civic communities, and that the safety-supporting environment in professional sports is underdeveloped compared with other areas of working life.     

Ocular injuries in sports

Eye injuries are common in sports. Team physicians need to be able to recognize and treat common injuries and know when to refer other problems. This article highlights the current treatment of common sports-related eye injuries and reviews some of the new literature. Nearly 90% of all sports-related eye injuries can be prevented with adequate eye protection and will be discussed in some detail in the article.     

Gene doping in sports

Gene or cell doping is defined by the World Anti-Doping Agency (WADA) as "the non-therapeutic use of genes, genetic elements and/or cells that have the capacity to enhance athletic performance". New research in genetics and genomics will be used not only to diagnose and treat disease, but also to attempt to enhance human performance. In recent years, gene therapy has shown progress and positive results that have highlighted the potential misuse of this technology and the debate of 'gene doping'. Gene therapies developed for the treatment of diseases such as anaemia (the gene for erythropoietin), muscular dystrophy (the gene for insulin-like growth factor-1) and peripheral vascular diseases (the gene for vascular endothelial growth factor) are potential doping methods. With progress in gene technology, many other genes with this potential will be discovered. For this reason, it is important to develop timely legal regulations and to research the field of gene doping in order to develop methods of detection. To protect the health of athletes and to ensure equal competitive conditions, the International Olympic Committee, WADA and International Sports Federations have accepted performance-enhancing substances and methods as being doping, and have forbidden them. Nevertheless, the desire to win causes athletes to misuse these drugs and methods. This paper reviews the current status of gene doping and candidate performance enhancement genes, and also the use of gene therapy in sports medicine and ethics of genetic enhancement.