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PubMed1987

Weight regulation practices in athletes: analysis of metabolic and health effects.

Athletes engage in a number of dietary and weight control practices which may influence metabolism, health, and performance. This paper reviews the literature on these factors with special emphasis on athletes who show large, frequent, and rapid fluctuations in weight (wrestlers) and athletes who maintain low weight and low percent body fat (e.g., distance runners, gymnasts, and figure skaters). A theory is presented which relates these weight patterns and the accompanying dietary habits to changes in body composition, metabolism, metabolic activity of adipose tissue, and the distribution of body fat. Changes in these physiological variables may be manifested in enhanced food efficiency (weight as a function of caloric intake) as the body seeks to protect and replenish its energy stores. This may explain the surprisingly low caloric intakes of some athletes. The health status of the athlete is a concern in this regard because there may be changes in fat distribution, risk factors for cardiovascular disease, and hormonal factors associated with reproductive functioning in both females and males. Amenorrhea in female athletes may be mediated at least in part by regional fat distribution; depletion of femoral fat depots (lactational energy reserves) may be the stimulus for cessation or disruption of menses.

Adipose Tissue↗
PubMed1987

Women, nutrition and exercise: a review of athletes' intakes and a discussion of energy balance in active women.

Given the heightened interest in nutritional aspects of exercise, and an increase in athletic participation by women, it appeared timely to review the nutritional implications of exercise in women. The initial part of this paper contains a compilation of published studies on the nutrient intakes of female athletes. These reveal that most groups of athletes have adequate nutrient intakes, and that their vitamin and mineral intakes appear to be superior to those of nonathletic women. The average energy intake of athletes in studies summarized in this paper was 2069 kcal, and for certain groups of athletes, energy intakes were even lower. How these women manage to train intensely while consuming energy intakes similar to those of sedentary women is not readily apparent, and for this reason, the remainder of the paper discusses energy balance as affected by activity. Methodological considerations related to assessment of the components of the energy balance equation (food intake, energy expenditure, and body energy stores) are presented, with a focus on considerations in women. The effects of activity on each of these components are then discussed in an attempt to determine whether some form of energy conservation may occur. Finally, effects of activity on the menstrual cycle are reviewed. The observed changes are discussed in relation to nutrition 1) in terms of how nutrition may play a role in their causation; and 2) in terms of their nutritional implications for the amenorrheic athlete, specifically as regards energy balance and bone density.

Amenorrhea↗
PubMed1988

An acute cardiovascular event in an endurance-trained athlete.

In athletes, symptoms and electrocardiographic patterns may mimic an acute coronary event. In addition, endurance athletes show significantly elevated heart-specific serum CK-MB enzyme activity in the first week after athletic competition. Also, cellular control of the CK-MB enzyme is consistently elevated in skeletal muscles of trained endurance athletes. Thus, all three criteria used in diagnosis of acute myocardial infarction may be found in the athlete's heart. Awareness of these potential findings in athletes as "heart patients" and curtail unnecessary hospitalizations.

Adult↗
PubMed1987

Nutrition knowledge of female varsity athletes and university students.

The objectives of this study were to compare the nutrition knowledge, including knowledge about nutrition in relation to physical activity, of female university students and members of varsity athletic teams and to document selected nutrition practices of those groups. Instruments developed for the study were completed by varsity athletes (no. = 70) and students not on teams (no. = 129). The two groups were similar in education, but the athletes were younger, taller, and heavier than the students and were considerably more active. The athletes used more nutritional supplements (especially iron) and were less likely to exclude red meat from their diet than were students. Scores on the knowledge test (which had a possible range of - 100% to 100%) averaged 34% for both team members and students. Both groups scored higher on general nutrition questions than on questions about nutrition in relation to activity. Among students, age, education, dietary pattern, total number of nutrition information sources, and length of time an activity program had been maintained were positively associated with nutrition knowledge. Those relationships were not detected among varsity athletes. It was concluded that female varsity athletes had levels of both general and sports-related nutrition knowledge that were similar to those of female students not participating on varsity teams.

Adult↗
PubMed1984

Weight control in the athlete.

Altering body composition either through reducing body fat or increasing muscle mass is a frequent and very important concern of large numbers of young athletes. When efforts to induce these body changes are approached with sound principles of nutrition and training, the resulting changes in body composition can make the desired contribution to health and fitness as well as contributing to increasing the athlete's performance potential. Any attempt to alter body composition must be planned over a significant time period, making it essential to initiate the program several weeks prior to the competing season. Significant increases or decreases in any body tissue component cannot be safely accomplished in a brief period. Supervision by a physician or another legitimate health professional is highly recommended to protect the motivated athlete from the abuses of faddists, quacks, and nutrition charlatans. The proper educational information regarding the ineffectiveness and hazards of drug use by the athlete are also to be dealt with. Having achieved a desired body composition, the athlete will recognize an achieved weight as his or her desired competing weight. Monitoring body weight two or three times weekly during the season will identify any involuntary changes in body weight that, if continued, will inevitably compromise athletic performance.

Adolescent↗
PubMed1983

Body composition of oligo/amenorrheic athletes.

Menstrual dysfunction in athletes may be related to low body weight or low body fat content. To investigate the relationship between body composition and menstrual function, body composition was evaluated by hydrostatic weighing in two groups of women: 14 athletes with oligo/amenorrhea and 28 athletes with regular menstruation. Age and height were similar in the two groups. In all of the weight parameters, including total body weight, percent ideal body weight, Livi Index, percent body fat, fat weight, and lean body weight, athletes with oligo/amenorrhea were significantly lighter than athletes with regular menstruation. We concluded that menstrual dysfunction in athletes is associated with low body weight, which is comprised of smaller amounts of both fat and lean body mass.

Adipose Tissue↗
PubMed1983

Vitamins, diet, and the athlete.

Good nutrition is necessary for good performance and optimal nutrition can make the difference in a championship performance. Optimal nutrition, however, is the result of good dietary habits and is not achieved by following a special diet for several days or by consuming a special food or supplement. Ergogenic aids can be categorized as mechanical, psychological and psychophysiologic, pharmacologic, and nutritional. The category of nutritional ergogenic aids includes special dietary regimens, special foods, and supplements. Of these, supplements, especially vitamins, pseudovitamins, and nonvitamins, are the most widely used. Supplements promoted as vitamins are more realistically described as vitamins, pseudovitamins, and nonvitamins. Pseudovitamins do have some activity related to vitamins, but at present no evidence exists for their requirement by humans. Nonvitamins are substances that may be found in naturally occurring foods but have no demonstrated nutritional value and are therefore not considered essential nutrients for humans or animals. Nutritional deficiencies can result in decreased performance. However, there is no evidence that consumption of nutrients beyond the requirements of the organism is beneficial and, in fact, some nutrients ingested at high levels for long periods of time result in toxicity. A review of the literature reveals that deterioration of physical performance resulting from prolonged vitamin deficiency is well documented. Numerous studies substantiate that once vitamin requirements are met, there appears to be no value in consuming additional amounts. Unfortunately, the literature is not as complete regarding vitamin or mineral toxicity. However, there is ample evidence to show that the possibility of toxicity is a genuine concern. Supplementation is common among athletes, with reported occurrence ranging from 54 to 84 per cent. Studies on the general public place the incidence of supplementation between 40 and 67 per cent. Although some dietary studies of athletes report the frequency of use of supplementation, few report the levels being consumed. A study currently in progress has found world-class amateur and professional athletes to use supplements at an incidence comparative to that reported in other studies of athletes. However, the levels at which supplements were taken are considered extremely high. Maintaining ideal weight and variety are the quantity and quality indexes for diet. Following sound nutritional principles will help to insure the athlete's ability to perform at his or her best. In general, a diet that provides 45 to 55 per cent of the calories from carbohydrate, 12 to 15 pr cent from protein, and 30 to 40 per cent from fat will meet the athlete's needs.(ABSTRACT TRUNCATED AT 400 WORDS)

Attitude to Health↗
PubMed1984

[Delayed menarche following early onset of athletic sports training].

To investigate the effect of athletic sports training on the onset of menarche, we submitted questionnaires to college students at University of Tsukuba. 311 students (174 college athletes and 137 non-athlete control students (group C) completed the questionnaires. The college athletes were divided into hard physical activity (group A) and moderate physical activity (group B) groups. The average age was similar in each group. The physical profile showed that group A and B were significantly (p less than 0.001) taller and heavier than those of group C. There was no significant difference among the average menarcheal age of group A (12.9 +/- 1.1 years, Mean +/- S.D.), group B (12.8 +/- 1.1 years) and group C (12.6 +/- 1.0 years). However, some of athletes in group A who had begun sports training before menarche had a later menarcheal age (13.1 +/- 1.1 years, p less than 0.001), and others who had begun training after menarche had a significantly earlier menarcheal age (12.1 +/- 0.9 years, p less than 0.001) whereas in group B the average menarcheal ages of premenarche-trained (12.9 +/- 1.1 years) and postmenarcheal-trained (12.3 +/- 1.1 years) students were similar to that of group C. These data indicate that early beginning of hard athletic training delays the onset of menarche.

Adolescent↗
PubMed1983

Four-year study of university athletes' dietary intake.

Baseline dietary intake data were collected for four years on 10 men's and 6 women's university athletic teams. Caloric intake means for specific teams were higher than those stated in nutrition textbooks (5,270 kcal for football, with a 14,000 kcal per day maximum). Athletes' caloric intakes cannot be grouped, as some athletes (wrestlers and gymnasts) have low intakes (400 kcal per day). Protein intake of all athletes except wrestlers and gymnasts is high (in many cases more than twice any recommendation). The diets of teams with high caloric intakes had a high (more than 50%) fat content. The fat content of the diets of other athletes ranged from 30% to 40%. The wrestling team had more members with poor nutrient intake (less than two-thirds of recommendations) than any other team. Poor vitamin A intakes were noted for all athletic teams studied. Low potassium intakes also were common. Members of women's teams had low iron intakes even though their protein and caloric intakes were high.

Computers↗
PubMed1982

Serum high-density lipoprotein cholesterol in male and female Olympic athletes.

High-density lipoprotein cholesterol (HDLC) is negatively associated with the risk of cardiovascular disease, and high levels of HDLC have been reported for physically active people. During the 1976 Olympic Games, held in Montreal, Canada, several physiological variables were measured in volunteer male and female Olympic athletes, from whom blood was collected. To compare these elite athletes with the general population and other physically active groups, HDLC was measured in serum samples that were kept at -80 degrees C and after precipitation of lipoproteins of lower densities by heparin-manganese. High-density lipoprotein cholesterol levels were significantly higher in women (65.2 +/- 2.1 N = 31) than in men (54.5 +/- 1.4, N = 64) (P less than 0.01). Olympic athletes had approximately 20% more HDLC than levels reported in the literature for the general population of North America. Levels of HDLC of the male Olympic athletes were comparable to those reported for elite world-class runners of comparable age. No correlation was found between HDLC and Quetelet index or maximum oxygen consumption. Levels of HDLC in athletes 20-24 yr of age were lower than in the other age groups studied and was positively correlated with age for athletes over 20 yr of age. Although a causal relationship between physical activity and HDLC remains to be established unequivocally, the present findings agree with several other studies that link various levels of physical activity with blood concentrations of HDLC higher than those found in sedentary populations.

Adult↗
PubMed1980

An objective method for measurement of musculo-skeletal size to characterize body physique with application to the athletic population.

The purpose of this paper is to present an objective method for estimating the musculo-skeletal size in relation to height for use in the study of body physique in athletes. The method can be applied to various male and female athletic groups and indicates the relative musculo-skeletal size by the extent to which each group falls above or below the regression of FFB on height as derived from the non-athletic male and female populations. Athletes within both sexes are found to differ greatly among performance events in this aspect of physique with track runners having the least amount of FFB related to height (within 1 standard error of the non-athletic population regression line) and professional football players having the most (2 to 3 standard errors above the non-athletic population line). Measurement of FFB can be obtained by underwater weighing or anthropometric dimensions and thus this approach offers application to the study and assessment of relative musculo-skeletal size in a variety of laboratory and field settings.

Anthropometry↗
PubMedDate not supplied

[Lipid and lipoprotein levels in athletes in different sports disciplines].

The purpose of this study was to investigate the effects of long-term high level physical exertion on plasma lipids and lipoproteins. Ninety-one young athletes, 70 men and 21 women, who practiced sports such as running, swimming, rowing, boxing and soccer, were studied. The control group included 101 healthy subjects, 77 men and 24 women, with sedentary life style. The mean plasma levels of total cholesterol (TC) (p = 0.04), low-density lipoprotein cholesterol (LDL-C) (p = 0.04) and the atherogenic index (p = 0.01) were lower, and high-density lipoprotein cholesterol (HDL-C) (p < 0.005) significantly higher in male athletes than in controls. Mean plasma lipids and lipoproteins concentrations were not significantly different in sportswomen when compared with their controls. The prevalence of hypercholesterolemia, hypertriglyceridemia and low HDL-C levels, were lower in male and female athletes of the five sport disciplines than in sedentary controls; however, only hypercholesterolemia (p < 0.05) and the atherogenic index (p < 0.01) were statistically different. These results, consistent with data previously published, show that low plasma levels of TG and high levels of HDL-C characterizes the athletes who practice an aerobic physical activity; additionally, in male athletes we found that long-term exercise appears to reduce LDL-C plasma levels. This latter finding agree with most, but not all, studies in the literature. We conclude that athletes have a lipid profile that may be protective against the development of atherosclerosis.

Adolescent↗
PubMed1994

Bone health and prevention of osteoporosis in active and athletic women.

Most studies have found lower bone mass among women with exercise-induced oligomenorrhea compared with eumenorrheic control women and athletes. These findings have important implications regarding increased risk of both stress fractures and premature osteoporosis. Active and athletic women should be encouraged to keep accurate records of their menstrual cycles. Any divergence from normal should be noted and carefully followed. Bone mass evaluation by bone densitometry for women with continued irregularities will allow assessment of skeletal status. Recommendations for treatment can be based, in part, upon these results, and follow-up scans will offer information on treatment efficacy. For athletes experiencing loss of periods accompanied by low bone mass, a decrease in training intensity and volume and an increase in total calories and calcium intake (1200 to 1500 mg/day) may be indicated. The dietary alterations could be accomplished by adding three glasses of skim milk per day to the diet. A program of resistance training designed to increase both muscle strength and mass may improve the skeletal profile of these athletes as well as protect against soft tissue injuries. Finally, estrogen replacement therapy (ERT) may be indicated for those women who are not willing to make changes in their exercise or dietary patterns. Although there are currently no controlled trials that examine the efficacy of ERT for treating these athletes, it is generally accepted that the doses prescribed to postmenopausal women are adequate for reducing bone loss among amenorrheic athletes. It is important that these women be followed with bone mass and serum measurements in order to evaluate the efficacy of the replacement therapy.

Adolescent↗
PubMed1994

Urinary incontinence in elite nulliparous athletes.

OBJECTIVE: To determine the prevalence of the symptom of urinary incontinence during athletic endeavors among a group of nulliparous, elite college varsity female athletes. METHODS: All women currently participating in varsity athletics at a large state university were asked to fill out a questionnaire about the occurrence of urinary incontinence while participating in their sport and during activities of daily life. One hundred forty-four of 156 eligible women (92%) responded. RESULTS: The mean age was 19.9 years, and all women were nulliparous. Overall, 40 athletes (28%) reported urine loss while participating in their sport. The proportions in different sports were: gymnastics 67%, basketball 66%, tennis 50%, field hockey 42%, track 29%, swimming 10%, volleyball 9%, softball 6%, and golf 0%. Two-thirds of the women who noted urine loss during athletics were incontinent more often than rarely. There were no statistically significant relations between incontinence and amenorrhea, weight, hormonal therapy, or duration of athletic activity. Activities most likely to provoke incontinence included jumping, high-impact landings, and running. Forty percent and 17% of the women first noted incontinence during their sport while in high school and junior high school, respectively. CONCLUSIONS: Incontinence during physical stresses is common in young, highly fit, nulliparous women. This suggests that there is a continence threshold which, when exceeded, can result in urine loss, even in the absence of known risk factors for incontinence.

Adolescent↗
PubMed1993

Efficacy of nutritional supplements used by athletes.

Findings on the efficacy of nutritional supplements used by athletes are reviewed. Many athletes have turned away from anabolic steroids and toward nutritional supplements in the hope of gaining a competitive edge without threatening their health. Athletes may require slightly more protein than sedentary people do to maintain positive nitrogen balance, but it is dubious whether extra dietary protein will help someone to achieve athletic goals. Purified amino acids have become a popular if expensive form of protein supplementation; there is no scientific evidence, however, to support their use. Excessive protein supplementation can lead to dehydration, gout, liver and kidney damage, calcium loss, and gastrointestinal effects. Supplementation with vitamins and minerals in excess of recommended daily allowances appears to have no effect on muscle mass or athletic performance. Other substances touted as having ergogenic properties are carnitine, cobamamide, growth hormone releasers, octacosanol, and ginseng; again, there is no reliable scientific evidence to support claims that products containing these compounds have ergogenic potential, and heavy supplementation may lead to adverse effects. Nutritional supplements are promoted through unsubstantiated claims by magazine advertisements, health food stores, coaches, and other sources. The FDA considers nutritional supplements to be foodstuffs, not drugs, and therefore has not required that they be proved safe and effective. Dosage guidelines are inadequate, and quality control is poor. The FDA has begun to revise regulations governing labeling and health claims for these products. There is little if any evidence that nutritional supplements have ergogenic effects in athletes consuming a balanced diet, and some products have the potential for harm.

Carnitine↗
PubMed1994

Risk and trigger factors for the development of eating disorders in female elite athletes.

This study examined risk factors and triggers for eating disorders in female athletes. Subjects included were all of the elite female athletes in Norway (N = 603), ages 12-35 yr, representing six groups of sports: technical, endurance, aesthetic, weight dependent, ball games, and power sports. The Eating Disorder Inventory was used to classify individuals at risk for eating disorders. Of the 117 athletes defined at risk, 103 were administered a structured clinical interview for eating disorders. A comparison group was also interviewed, consisting of 30 athletes chosen at random from a pool not at risk and matched to the at-risk subjects on age, community of residence, and sport. Ninety-two of the at-risk athletes met criteria for anorexia nervosa, bulimia nervosa, or anorexia athletica. The prevalence of eating disorders was higher in sports emphasizing leanness or a specific weight than in sports where these are less important. Compared with controls, eating disordered athletes began both sports-specific training and dieting earlier, and felt that puberty occurred too early for optimal performance. Trigger factors associated with the onset of eating disorders were prolonged periods of dieting, frequent weight fluctuations, a sudden increase in training volume, and traumatic events such as injury or loss of a coach.

Adolescent↗
PubMed1997

Accuracy of Calorie Counter method to assess daily energy expenditure and physical activities in athletes and nonathletes.

OBJECTIVE: The aim of this study was to examine the accuracy of the Calorie Counter personal activity computer (CC method) for athletic activity. DESIGN: An observational study for a week or on a day. SETTING: Healthy Japanese volunteers. PARTICIPANTS: Nonathletes (54 males and 53 females) and 38 male athletes, with ages between 13 and 73 years old. MEASURES: Daily energy expenditure and weekly physical activity were simultaneously assessed using the CC method and a daily record on physical activity (daily record method) for a week for the nonathletes and one day for the athletes. RESULTS: Mean daily energy expenditures were 9630 (standard deviation, SD, 1250) kJ.d-1 by the CC method, compared with 9530 (SD, 1120) kJ.d-1 by the daily record method for male nonathletes; 7822 (SD, 768) kJ.d-1 and 7790 (SD, 810) kJ.d-1, respectively, for female nonathletes; and 1120 (SD, 1520) kJ.d-1 and 11580 (SD, 1580) kJ.d-1, respectively, for athletes. The correlation coefficients between daily energy expenditures by these two methods ranged from 0.72 to 0.90. Mean daily physical activities were 1520 (SD, 637) kJ.d-1 by the CC method, compared with 1580 (SD, 691) kJ.d-1 by the daily record method for male nonathletes; 1033 (SD, 318) kJ.d-1 and 1080 (SD, 346) kJ.d-1, respectively, for female nonathletes; and 2770 (SD, 914) kJ.d-1 and 3250 (SD, 1090) kJ.d-1, respectively, for athletes. The correlation coefficients between daily physical activities by these two methods ranged from 0.56 to 0.96. CONCLUSIONS: Our results suggest that the CC method may be reliable enough for assessing the energy expenditure in athletes as well as in nonathletes during free-living activities.

Adolescent↗
PubMed1998

The electrocardiographic T wave changes in highly trained athletes during training. An old problem revisited.

OBJECTIVE: To evaluate the T-wave pattern alterations during vigorous training in elite athletes. SETTING: Institute of Sport Science in Rome and National Rowing Center in Piediluco, Italy. STUDY POPULATION: Nine male and 7 female rowers of the national team were examined prospectively at different times of their conditioning period. METHODS: All athletes underwent electrocardiography and echocardiography; the ecg was analyzed for QRS voltages and axis, T-wave pattern and QTc interval; from echocardiography the left ventricular (LV) cavity dimension, wall thickness and mass were calculated. From Doppler-echocardiography the transmitral diastolic LV filling pattern was evaluated. RESULTS: Variation of T-wave voltages was seen in all the athletes. Specifically, during the low-intensity training period the T-wave pattern was positive and increased in voltage (T-wave max amplitude in V6 increased to 130% in male and 100% in female than pretraining values). During the peak training a variety of patterns was observed, and a transient flattening was present in 50% of subjects. No concomitant alteration of heart rate, QRS and T-wave axis and QTc duration were observed. No significant changes of cavity dimension, wall thickness, LV mass index and Doppler-derived diastolic peak flow velocities were detected during the study period. CONCLUSIONS: Transient changes of T-wave pattern may occur in athletes as an effect of athletic conditioning, without changes of cardiac dimension or alteration of indexes of LV function. This finding supports the role of ecg monitoring to follow-up the individual athletes response to training exercise load.

Adolescent↗