Archive for the ‘Wrestling’ Category

Lower muscle mass and an increase in body fat are common consequences of growing older.

While exercise is a proven way to prevent the loss of muscle mass, a new study led by McMaster researcher Dr. Mark Tarnopolsky shows that taking a combination of creatine monohydrate (CrM) and conjugated linoleic acid (CLA) in addition to resistance exercise training provides even greater benefits.

The study to be published on Oct. 3 in PLoS One, an international, peer-reviewed online journal of the Public Library of Science, involved 19 men and 20 women who were 65 years or older and took part in a six-month program of regular resistance exercise training.

In the randomized double blind trial, some of the participants were given a daily supplement of creatine (a naturally produced compound that supplies energy to muscles) and linoleic acid (a naturally occurring fatty acid), while others were given a placebo. All participants took part in the same exercise program.

The exercise training resulted in improvements of functional ability and strength in all participants, but those taking the CrM and CLA showed even greater gains in muscle endurance, an increase in fat-free mass and a decrease in the percentage of body fat.

“This data confirms that supervised resistance exercise training is safe and effective for increasing strength and function in older adults and that a combination of CrM and CLA can enhance some of the beneficial effects of training over a six month period,” said Tarnopolsky, a professor of pediatrics and medicine.

This study provides functional outcomes that build on an earlier mechanistic study co-led by Tarnopolsky and Dr. S. Melov at the Buck Institute of Age Research, published in PLoS One this year, which provided evidence that six months of resistance exercise reversed some of the muscle gene expression abnormalities associated with the aging process.

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Article adapted by MD Sports Weblog from original press release.
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Contact: Veronica McGuire
McMaster University

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Steroid use starts early, decreases as teens grow older

Participation in sports with real or perceived weight requirements, such as ballet, gymnastics, and wrestling, is strongly associated with unhealthy weight control behaviors and steroid use in teens, according to researchers at the University of Minnesota.

Research published in the March 2007 issue of the Journal of the American Dietetic Association found nearly 6 percent of males between the ages of 12 and 18 who participated in weight-related sports induced vomiting within the week prior to being surveyed, as compared to only 0.9 percent of males who did not participate in weight- related sports. The use of diuretics within the previous year was reported by 4.2 percent of males in a weight-related sport, as opposed to 0.8 percent who did not participate in a weight-related sport.

Steroid use was reported in 6.8 percent of females who reported participating in weight-related sports, compared to 2.3 percent of those that weren’t active in a weight-related sport. Vomiting and using laxatives were also more likely in girls who were active in weight-related sports.

“The link between unhealthy weight-control behaviors and weight-related sports, especially in boys, is alarming,” said Marla Eisenberg, Sc.D., M.P.H., assistant professor at the University of Minnesota Medical School Department of Pediatrics. “Parents and coaches should emphasize skill and talent instead of weight and body image and educate teens about the negative health effects of steroid use and extreme weight control.” Researchers surveyed over 4,500 middle and high school students from the Minneapolis/St. Paul metro area. The students were asked if they had engaged in self-induced vomiting, used diet pills or laxatives, or used steroids within the previous week and year.

Steroid use in teens peaks at young age, but overall use has not increasedIn a separate study, published in the March 2007 issue of Pediatrics, University of Minnesota researchers surveyed the same teen population again five years later. They found that steroid use among teens peaked at 5 percent in middle school boys and girls, but as they grew older, steroid use declined significantly.

“It is encouraging to see that the majority of young people who reported using steroids in 1999 stopped using them as they got older,” said Patricia van den Berg, Ph.D., lead author of the study from the University of Minnesota School of Public Health. “But even given this decline, between one and three in 100 teens still reported using steroids within the last year when asked again 5 years later.”

Researchers conducted the longitudinal study with more than 2,000 adolescents to examine changes in eating patterns, weight, physical activity, and related factors over five years. Participants completed two surveys, one in 1999 and one in 2004, to determine if there were changes in steroid use.

Overall, 1.7 percent of boys and 1.4 percent of girls between the ages of 15 and 23 reported steroid use in 2004. Those that reported use early on were 4 to 10 times more likely to use later in life.

Boys who reported wanting a larger body in 1999, as well as those who said they used healthy weight-control behaviors, were more likely to take steroids when they were older. In contrast, girls who were heavier, less satisfied with their weight, and who had limited knowledge of healthy eating and exercise habits were more likely to take steroids as they grew older.

The study found no significant change in steroid use overall among teens from 1999-2004. “Our research suggests that the increased media coverage surrounding steroid use among athletes in recent years hasn’t led to a huge rise in steroid use in young people,” said van den Berg.

Anabolic-androgenic steroids are synthetic derivatives of the male hormone, testosterone. They are typically taken to increase muscle mass and strength for either improved sports performance or enhanced appearance. These steroids have significant negative effects on the body’s muscles, bones, heart, reproductive system, liver, and psychological state.

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Article adapted by MD Sports Weblog from original press release.
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Contact: Liz Wulderk
University of Minnesota 
 

Project EAT: Eating Among Teens Both studies are part of Project EAT: Eating Among Teens, research designed to investigate the factors influencing the eating habits of adolescents, to determine if youth are meeting national dietary recommendations, and to explore dieting, physical activity patterns, and related factors among youth. The project is designed to build a greater understanding of the socio-environmental, personal, and behavioral factors associated with diet and weight-related behaviors during adolescence so more effective nutrition interventions can be developed.

The studies were supported by the Maternal and Child Health Program, Health Resources and Services Administration, the Department of Health and Human Services, and a training grant from the Centers for Disease Control.

Myostatin (MSTN) is a transforming growth factor-ß (TGF-ß) family member that plays a critical role in regulating skeletal muscle mass [1]. Mice engineered to carry a deletion of the Mstn gene have about a doubling of skeletal muscle mass throughout the body as a result of a combination of muscle fiber hyperplasia and hypertrophy [2]. Moreover, loss of myostatin activity resulting either from postnatal inactivation of the Mstn gene [3], [4] or following administration of various myostatin inhibitors to wild type adult mice [5][7] can also lead to significant muscle growth. Hence, myostatin appears to play as least two distinct roles, one to regulate the number of muscle fibers that are formed during development and a second to regulate growth of muscle fibers postnatally. The function of myostatin appears to have been conserved across species, as inactivating mutations in the myostatin gene have been demonstrated to cause increased muscling in cattle [8][11] , sheep [12], dogs [13] and humans [14]. As a result, there has been considerable effort directed at developing strategies to modulate myostatin activity in clinical settings where enhancing muscle growth may be beneficial. In this regard, loss of myostatin activity has been demonstrated to improve muscle mass and function in dystrophic mice [15][17] and to have beneficial effects on fat and glucose metabolism in mouse models of obesity and type II diabetes [18].

Myostatin is synthesized as a precursor protein that undergoes proteolytic processing to generate an N-terminal propeptide and a C-terminal dimer, which is the biologically active species. Following proteolytic processing, the propeptide remains bound to the C-terminal dimer and maintains it in an inactive, latent complex [6], [19], [20], which represents one of the major forms of myostatin that circulates in the blood [21], [22]. In addition to the propeptide, other binding proteins are capable of regulating myostatin activity in vitro, including follistatin [19], [21], FLRG [22], and Gasp-1 [23]. We previously showed that follistatin can also block myostatin activity in vivo; specifically, we showed that follistatin can ameliorate the cachexia induced by high level expression of myostatin in nude mice [21] and that transgenic mice expressing follistatin in muscle have dramatic increases in muscle mass [19]. Here, I show that overexpression of follistatin can also cause substantial muscle growth in mice lacking myostatin, demonstrating that other TGF-ß related ligands normally cooperate with myostatin to suppress muscle growth and that the capacity for enhancing muscle growth by targeting this signaling pathway is much larger than previously appreciated.

Results

Increased muscle mass in transgenic mice expressing FLRG

Previous studies have identified several proteins that are normally found in a complex with myostatin in the blood [22], [23]. One of these is the follistatin related protein, FLRG, which has been demonstrated to be capable of inhibiting myostatin activity in vitro. To determine whether FLRG can also inhibit myostatin activity in vivo, I generated a construct in which the FLRG coding sequence was placed downstream of a myosin light chain promoter/enhancer. From pronuclear injections of this construct, a total of four transgenic mouse lines (Z111A, Z111B, Z116A, and Z116B) were obtained containing independently segregating insertion sites. Each of these four transgenic lines was backcrossed at least 6 times to C57 BL/6 mice prior to analysis in order to control for genetic background effects. Northern analysis revealed that in three of these lines the transgene was expressed in skeletal muscles but not in any of the non-skeletal muscle tissues examined (Figure 1); in the fourth line, Z111B, the expression of the transgene was below the level of detection in these blots. As shown in Table 1, all four lines exhibited significant increases in muscle weights compared to wild type control mice. These increases were observed in all four muscles that were examined as well as in both sexes. Moreover, the rank order of magnitude of these increases correlated with the rank order of expression levels of the transgene; in the highest-expressing line, Z116A, muscle weights were increased by 57–81% in females and 87–116% in males compared to wild type mice. Hence, FLRG is capable of increasing muscle growth in a dose-dependent manner when expressed as a transgene in skeletal muscle.

The research was funded by grants from the NIH and the Muscular Dystrophy Association and by a gift from Merck Research Laboratories.

See http://www.jhu.edu/sejinlee/%20for%20more%20information for more information.
Citation: Lee S-J (2007) Quadrupling Muscle Mass in Mice by Targeting TGF-ß Signaling Pathways. PLoS ONE 2(8): e789. doi:10.1371/journal.pone.0000789

LINK TO THE PUBLISHED ARTICLE http://www.plosone.org/doi/pone.0000789

Source: Nick Zagorski
Johns Hopkins Medical Institutions

The serious athlete knows better than to rely just on a famous cereal to provide additional energy in preparation of a sporting event. Supplements have assumed an important role in today’s training regimen. Some – such as anabolic steroids — have been deemed illegal by most sports authorities. Others – such as caffeine and creatine — are controversial yet presently allowed.Background
Caffeine, the primary ingredient of coffee, is used as a central nervous system stimulant, diuretic, circulatory and respiratory stimulant, and as an adjunct in the treatment of headaches. Evidence shows that caffeine intensifies muscle contractions, masks the discomfort of physical exertion, and even speeds up the use of the muscles’ short-term fuel stores. Some exercise physiologists believe that caffeine might improve performance by increasing fat oxidation and conserving muscle glycogen.

Creatine is used by athletes to increase lean body mass and improve performance in single and repetitive high-intensity, short-duration exercise tasks such as weightlifting, sprinting, and cycling. It is a popular nutritional supplement that is used by physically active people – from recreational exercisers to Olympic and professional athletes. According to a recent survey, 28 percent of athletes in an NCAA Division IA program reported using creatine. The creatine that is normally present in human muscle may come from two potential sources: dietary (animal flesh) and internally manufactured.

The purpose of creatine supplementation is to increase either total creatine stores or phosphocreatine (PCr) stores within muscle. Supplementation increases the rate of resynthesis of creatine phosphate following exercise. Various studies have shown increased muscle PCr levels after supplementing with 20-30 grams of creatine monohydrate daily.

Creatine supplementation has also been known to shorten relaxation time during intermittent maximal iosometric muscle contraction. This shortened time, coupled with a creatine loaded muscle facilitates calcium absorption into the sarcoplasmic reticulum (the endoplasmic reticulum of skeletal and cardiac muscle). However, some believe that caffeine intake enhances calcium release from the sarcoplasmic reticulum.

The Study
This has lead a research team from Belgium to suggest that the combined effects of creatine and caffeine supplementation may be counterproductive to creatine’s effect on muscle relaxation time. The authors of the study, “Opposite Actions of Caffeine and Creatine on Muscle Relaxation Time in Humans” are P. Hespel, B. Op ‘T Eijnde, and M. Van Leemputte, all from the Department of Kinesiology, Katholieke Universiteit Leuven, Leuven, Belgium. Their findings appear in the February 2002 edition of the Journal of Applied Physiology.

Methodology
Ten physical education students (nine men and one woman) participated in the study. They were told to abstain from medication and caffeine intake one week prior to the experiment. The subjects were additionally asked to avoid changes in their level of physical activity and diet during the 25-week duration of the study. In this double blind experiment, the subjects performed the exercise test before and after creatine supplementation, short-term caffeine intake, creatine supplementation in the short term, acute caffeine intake, or a placebo.

This study required the random assignment of the students into five experimental protocols, each lasting eight days. Three elements were measured during an experiment consisting of 30 intermittent contractions of quadriceps entailing two seconds of stimulation and two seconds of rest. Measurements included maximum torque (Tmax), contraction time (CT) from 0.25 to 0.75 of Tmax, and relaxation time (RT) from 0.75 to 0.25 of max.

Results
Key findings of this study included:

· a confirmation of the fact that oral creatine supplementation shortens muscle relaxation time in humans: relation time was reduced by five percent and was significantly shorter than after the placebo;

· discovery that the intake of caffeine, combined with a daily creatine supplement, counteracted the beneficial effects of creatine intake on relaxation time and fatigue enhanced this inhibitory effect; and

· the observation that caffeine reduces the functional capacity of sacroplasmic reticulum calcium ATPase.

Conclusion The researchers believe that the findings from this experiment offer indirect evidence that suggests that facilitation of muscle relaxation may be important to the ergogenic action of creatine supplementation as well as power production during sprint exercises.

However, for the athlete in training, the key finding is that sustained caffeine intake, over a three-day period, negates the benefits of creatine supplements.

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Article adapted by MD Only Sports Weblog from original press release.
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Contact: Donna Krupa
American Physiological Society

Peak athletic performance may be related to time of day, suggests a University of Chicago study being presented to the Endocrine Society’s annual meeting, ENDO 2001, in Denver, Colorado, on June 22, 2001. The study shows that the response of the systems regulating energy metabolism and some hormones differs according to when in the day exercise is performed.

Subjects who exercised at night had much larger drops in glucose levels in response to exercise than at other times of day. Exercise in the evening and at night elicited large increases in the levels of two hormones important for energy metabolism, cortisol and thyrotropin. Exercise at other times of day had much smaller effects on these hormones. In contrast, marked increases in growth hormone levels in response to exercise were not effected by the time of day.

“The effects of exercise we observed may explain how some times of day could be better than others for regular exercise or athletic performance, as we might expect from anectdotally reported variations in peak athletic performance,” said Orfeu Buxton, Ph.D., a post-doctoral fellow in endocrinology at the University of Chicago. “We found strong evidence for substantial changes in glucose metabolism and an array of hormonal responses to 1-hour, high-intensity exercise, dependent on the timing of the exercise. Circadian rhythms, generated by our 24-hour internal clock, appear to play an important role in the complex response to exercise.”

For the study, conducted in the Clinical Research Center of the University of Chicago, 40 healthy men, between the ages of 20 and 30, were divided into five groups. Four groups exercised vigorously for one hour on a stair-stepper in the morning, afternoon, evening or night. A control group did not exercise. A standard marker, the timing of melatonin secretion, was used to determine the timing of each individual’s daily rhythm, his circadian “clock time.”

When not exercising, the subjects rested in bed with constant glucose infusion to avoid fluctuation in their blood sugar levels caused by intermittent meals. Blood levels of the “circadian hormones,” melatonin, cortisol and thyrotropin, and the levels of growth hormone and glucose were compared to blood levels for the same time of day in the resting control subjects.

The importance of timing for hormonal secretion and energy metabolism is demonstrated by the distinct 24-hour patterns of secretion for each hormonal system. One hormone may be actively secreted in a complex pulsating pattern while another may be in a resting phase.

Many circadian rhythms, such as heart rate, oxygen consumption, and cardio-pulmonary function play a role in athletic performance. Rhythmic patterns of hormonal secretion provide internal temporal organization essential to the coordination of physiological processes. Physical exercise is associated with marked metabolic changes and can elicit a variety of neuroendocrine responses. Although these metabolic and hormonal responses to morning exercise are well-documented, few studies have examined the effects of exercise at other times of day.

“Our study covers new ground, demonstrating variation in the effects of exercise at four different times of day, with circadian time precisely quantified, with a practical duration of exercise, and with a high intensity designed to elicit maximal effects” said Buxton.

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Article adapted by MD Only Sports Weblog from original press release.
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Contact: Jeanne Galatzer-Levy
University of Chicago Medical Center

Co-authors on the study include, André J. Scheen, M.D., Division of Diabetes, Nutrition and Metabolic Disorders, University of Liége, Belgium; Mireille L’Hermite-Balériaux, Ph.D., Laboratory of Experimental Medicine, Université Libre de Bruxelles, Belgium and Eve Van Cauter, Ph.D., Department of Medicine, University of Chicago.

This work was supported by grants from the Air Force Office of Scientific Research and from the Department of Defense. The University of Chicago Clinical Research Center is supported by a National Institutes of Health grant.

When it comes to coaching, the pep talk is better than the locker room tirade, University of Florida researchers have found.In a project that applied methods previously used only in classroom settings, a team headed by Professor Robert Singer found that changing people’s attributions, or how they think about themselves, influenced their performance in sports tasks they sought to learn.

“How we think about how we will do and how we’ve just done can very much affect our persistence, our attitudes and our achievements,” said Singer, chair of UF’s department of exercise and sport sciences. “It’s not only a belief in what you can do, it’s also an understanding of thinking more objectively.”

The technique is known as attribution training, which involves using people’s self-perceptions and the extent to which they feel they can control their own behavior to help them succeed at various tasks. Those who believe they can control and change how they feel about themselves are said to have constructive attributions.

In the study, scheduled to be published in March in The Sport Psychologist, Singer and UF colleague Iris Orbach divided 35 college-age beginning tennis players into three groups, each of which was given different instructions regarding personal failure. The first was told they could control their attributions and effort and could change their performance. The second was told their failures were due to a lack of innate ability. The third group was told nothing.

In four trials, the first group scored consistently better in performance, expectation, success perception and emotional control, Singer said. For example, on a test to measure feelings of personal control over behavior, the first group scored twice as high as the control group, while the second group scored below the control group.

In a related study in 1997 that focused on basketball time trials, the first group improved their final time between the first and fourth trials more than twice as much as the control group and more than nine times as much as the second group did.

“When it comes down to it, the primary thing is that you really have to understand what helps you to achieve and what’s under your control,” Singer said. “What has been observed is that those individuals who tend to have more constructive attributions tend to persist longer and tend to achieve more than those who do not have constructive attributions.”

Most studies associated with attribution training techniques have been conducted in the area of education, with the goal of raising the standards for children who are underachievers in the classroom. Singer and Orbach were among the first in the world to apply the techniques to sports.

“Why not try this in a sports setting?” Singer said. “The typical design is to train one group with an attributional orientation that reflects that if you try harder and you try smarter, you’ll have a greater chance of doing well. You’ll learn the skills better and think better things will happen.”

Although it is a common perception that believing in yourself can lead you to success, Singer said his study could have a significant impact on the way people teach and learn athletic activities.

“A lot of times in sports, there’s a negative attitude and a lot of criticism that goes on,” he said. “Probably many athletes and coaches don’t realize the significance of what we’re talking about and the relevance of how people think … I believe that if there’s a better understanding by coaches as to the kind of feedback they give to athletes and how stuff is delivered to them, it could make a difference.”

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Article adapted by MD Only Sports Weblog from original press release.
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Contact: Kristin Harmel
University of Florida

Adolescents who don’t get enough sleep might be jeopardizing their athletic performance, and high school sports teams on the west coast may be at a disadvantage if they play east coast rivals, says Mary Carskadon, PhD, of the Bradley Hasbro Children’s Research Center.Carskadon, a leader in the field of sleep research, compared the results of studies that measured sleep patterns and circadian rhythms in children and adolescents in the May 24 issue of Clinics in Sports Medicine. While it’s widely known that lack of sleep can affect learning, mood and behavior in teenagers, Carskadon suggests that insufficient sleep can also negatively impact teen athletes in a number of ways.

“Young people live in nearly a constant state of chronic insufficient sleep,” says Carskadon, “and adolescents who don’t get enough sleep on a regular basis are extremely impaired in the morning.”

For this reason, she suggests that adolescent travel teams heading westward across time zones have an advantage over home teams early in the day.

While most adults who routinely travel from coast to coast might be well aware of the difficulty adjusting to a different time zone, teens are at even more of a disadvantage.

Evidence suggests that the adolescent circadian rhythm, or internal biological clock, is still adjusting, and their internal day-length is longer than that of adults. This means that teens might not be ready to fall asleep until later in the evening, or may wake up later in the morning.

“For morning games, the home team might still be in the lowest point of alertness,’ while the team that headed west will have the advantage of having been awake for an hour or so longer, and thus have more energy.”

Additionally, if the eastern team arrives the night before, they would gain an extra hour or two of sleep, which can improve focus, alertness, and better reaction skills.

Conversely, she warns that athletic teams taking extended training trips (eg. spring break) of a week or more may experience schedule difficulties on the return home.

“This scenario is most problematic for teams on the east coast that travel west, as student athletes may return with a significant sleep-phase delay that is difficult to correct,” Carskadon says.

Lack of sleep doesn’t just affect athletics in teenagers. Studies repeatedly show that reaction time, vigilance, learning and alertness are impaired by insufficient sleep; so students with short nights and irregular sleep patterns perform poorly in school and in other aspects of their life and have a tendency for a depressed mood.

“Circadian and lifestyle changes conspire to place sleep of adolescents at a markedly delayed time relative to younger children and to adults,” says Carskadon.

In fact, studies have shown that teenagers need as much, if not more sleep as younger children (an average of 9.25 hours per night) but as they mature, their bodies are able to stay alert later into the night.

She cites part-time jobs, caffeinated beverages, social activities, away-games and long practices as factors that help contribute to chronic sleep deprivation for young people.

Is there any reprieve? An afternoon nap can help, but only for so long. Carskadon found that a 45-minute nap taken approximately six hours after waking supported alertness and mood for about eight hours. For a teen who starts his day at 6:30 am, a lunchtime nap could keep him going till 8 or 9 pm.

However, Carskadon warns that afternoon naps don’t help morning fatigue the next day.

“In order to help adolescents do their best, parents need to take an active role in helping set a regular sleep pattern for their teen.”

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Article adapted by MD Only Sports Weblog from original press release.
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Contact: Carol L. Hoy
Lifespan

Mary Carskadon, PhD, directs the Bradley Hospital Sleep and Chronobiology Research Laboratory, and is a Professor of Psychiatry and Human Behavior at Brown Medical School in Providence, RI. She is currently recruiting children and young adults for several studies.

Founded in 1931 as the nation’s first psychiatric hospital for children, Bradley Hospital (www.bradleyhospital.org) remains a premier medical institution devoted exclusively to the research and treatment of childhood psychiatric illnesses. Bradley Hospital, located in Providence, RI, is an affiliate of Brown Medical School and ranks in the top third of private hospitals receiving funding from the National Institutes of Health. Its research arm, the Bradley Hasbro Children’s Research Center (BHCRC), brings together leading researchers in such topics as: autism, colic, childhood sleep patterns, HIV prevention, infant development, obesity, eating disorders, depression, obsessive-compulsive disorder (OCD) and juvenile firesetting. Bradley Hospital is a member of the Lifespan health system.