Archive for the ‘Powerlifting’ Category

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

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Although it’s too soon to recommend dropping by Starbucks before hitting the gym, a new study suggests that caffeine can help reduce the post-workout soreness that discourages some people from exercising.In a study to be published in the February issue of The Journal of Pain, a team of University of Georgia researchers finds that moderate doses of caffeine, roughly equivalent to two cups of coffee, cut post-workout muscle pain by up to 48 percent in a small sample of volunteers.

Lead author Victor Maridakis, a researcher in the department of kinesiology at the UGA College of Education, said the findings may be particularly relevant to people new to exercise, since they tend to experience the most soreness.

“If you can use caffeine to reduce the pain, it may make it easier to transition from that first week into a much longer exercise program,” he said.

Maridakis and his colleagues studied nine female college students who were not regular caffeine users and did not engage in regular resistance training. One and two days after an exercise session that caused moderate muscle soreness, the volunteers took either caffeine or a placebo and performed two different quadriceps (thigh) exercises, one designed to produce a maximal force, the other designed to generate a sub-maximal force. Those that consumed caffeine one-hour before the maximum force test had a 48 percent reduction in pain compared to the placebo group, while those that took caffeine before the sub-maximal test reported a 26 percent reduction in pain.

Caffeine has long been known to increase alertness and endurance, and a 2003 study led by UGA professor Patrick O’Connor found that caffeine reduces thigh pain during moderate-intensity cycling. O’Connor, who along with professors Kevin McCully and the late Gary Dudley co-authored the current study, explained that caffeine likely works by blocking the body’s receptors for adenosine, a chemical released in response to inflammation.

Despite the positive findings in the study, the researchers say there are some caveats. First, the results may not be applicable to regular caffeine users, since they may be less sensitive to caffeine’s effect. The researchers chose to study women to get a definitive answer in at least one sex, but men may respond differently to caffeine. And the small sample size of nine volunteers means that the study will have to be replicated with a larger study.

O’Connor said that despite these limitations, caffeine appears to be more effective in relieving post-workout muscle pain than several commonly used drugs. Previous studies have found that the pain reliever naproxen (the active ingredient in Aleve) produced a 30 percent reduction in soreness. Aspirin produced a 25 percent reduction, and ibuprofen has produced inconsistent results.

“A lot of times what people use for muscle pain is aspirin or ibuprofen, but caffeine seems to work better than those drugs, at least among women whose daily caffeine consumption is low,” O’Connor said.

Still, the researchers recommend that people use caution when using caffeine before a workout. For some people, too much caffeine can produce side effects such as jitteriness, heart palpitations and sleep disturbances.

“It can reduce pain,” Maridakis said, “but you have to apply some common sense and not go overboard.”

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Article adapted by MD Only Sports Weblog from original press release.
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Contact: Sam Fahmy
University of Georgia

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

The majority of non-medical anabolic-androgenic steroid (AAS) users are not cheating athletes or risk-taking teenagers. According to a recent survey, containing the largest sample to date and published in the online open access publication, Journal of the International Society of Sports Nutrition, the typical male user is about 30 years old, well-educated, and earning an above-average income in a white-collar occupation. The majority did not use steroids during adolescence and were not motivated by athletic competition or sports performance.

The study, conducted by a collaboration of researchers from around the country coordinated by Jason Cohen, Psy.D. candidate, used a web-based survey of nearly 2,000 US males. Whereas athletes are tempted to take anabolic steroids to improve sports performance, the study suggests that physical self-improvement motivates the unrecognized majority of non-medical AAS users who particularly want to increase muscle mass, strength, and physical attractiveness. Other significant but less highly ranked factors included increased confidence, decreased fat, improved mood and attraction of sexual partners.

Although often considered similar to abusers of narcotics and other illicit drugs (e.g., heroin or cocaine), non-medical AAS users are remarkably different. These users follow carefully planned drug regimens in conjunction with a healthy diet, ancillary drugs and exercise. As opposed to the spontaneous and haphazard approach seen in abusers of psychotropic drugs, everything is strategically planned to maximize benefits and minimize harm. “This is simply not a style or pattern of use we typically see when we examine substance abuse” said Jack Darkes, Ph.D., one of the authors. “The notions of spontaneous drug seeking and loss of control do not apply to the vast majority of AAS users,” added co-author Daniel Gwartney, M.D.

“These findings question commonly held views of typical AAS users and their underlying motivations,” said Rick Collins, one of the study’s authors. “The focus on ‘cheating’ athletes and at risk youth has led to irrelevant policy as it relates to the predominant group of non-medical AAS users. The vast majority of AAS users are not athletes and hence, are not likely to view themselves as cheaters. The targeting of athletes through drug testing and other adolescent or sports-based interventions has no bearing on non-competitive adult users.” The study concludes that these AAS users are a driven and ambitious group dedicated to gym attendance, diet, occupational goals and educational attainment. “The users we surveyed consider that they are using directed drug technology as one part of a strategy for physical self-improvement within a health-centered lifestyle,” said Collins. “Effective public policy should begin by accurately identifying who’s using steroids and why. We hope our research – the largest adult survey of non-medical AAS use we know of – is a significant step forward in that direction.”

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Article adapted by MD Only Sports Weblog from original press release.
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Contact: Charlotte Webber
BioMed Central

Article:
A League of Their Own: Demographics, Motivations and Patterns of Use of 1,955 Male Adult Non-Medical Anabolic Steroid Users in the United States
Jason Cohen, Rick Collins, Jack Darkes and Dan Gwartney
Journal of the International Society of Sports Nutrition (in press)

During embargo, article available at: http://www.jissn.com/imedia/1374735248154681_article.pdf?random=454689

After the embargo, article available from the journal website at: http://www.jissn.com

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

Active individuals lacking in B-vitamins – including college athletes and other elite competitors — may perform worse during high-intensity exercise and have a decreased ability to repair and build muscle than counterparts with nutrient-rich diets, according to recent Oregon State University research published in the International Journal of Sport Nutrition and Exercise Metabolism.The B-vitamins include thiamin, riboflavin, vitamin B-6, B-12 and folate. These micronutrients are necessary during the body’s process for converting proteins and sugars into energy, and are used during the production and repair of cells, including red blood cells.

For active individuals a marginal deficiency in the nutrients may impact the body’s ability to repair itself, operate efficiently and fight disease, said Melinda Manore, researcher in the Colleges of Agricultural and Health and Human Sciences. Manore analyzed the athletic performance of several elite and collegiate athletes in her research, as well as less competitive individuals.

The stress on the body’s energy producing pathways during exercise, the changes in the body’s tissues resulting from training, an increase in the loss of nutrients in sweat, urine and feces during and after strenuous activity and the additional nutrients needed to repair and maintain higher levels of lean tissue mass present in some athletes and individuals may all affect an individuals B-vitamin requirements, said Manore.

“Many athletes, especially young athletes involved in highly competitive sports, do not realize the impact their diets have on their performance,” said Manore, who is also an Extension Service nutrition scientist. “By the time they reach adulthood they can have seriously jeopardized their abilities and their long-term health.”

Current national B-vitamin recommendations for active individuals may be inadequate, and athletes who follow the recommended daily allowances set by the U.S. government may be receiving lower amounts of nutrients than there bodies need, said Manore. Athletes who restrict calories or limit food groups like dairy or meat have an increased chance of deficiency. Such athletes are often concerned about maintaining a low body weight for sports like gymnastics and wrestling.

“The most vulnerable people are often the individuals society expects to be the healthiest,” said Manore. “There’s a lot of pressure on women in particular to look like an ‘athlete.’ Unfortunately for some people that means skinny and petite, rather than healthy and strong.”

The B-vitamins are in whole and enriched grains, dark green vegetables, nuts, and many animal and dairy products. Manore suggests athletes and individuals with poor or restricted diets consider taking a multivitamin or mineral supplement.

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Article adapted by MD Only Sports Weblog from original press release.
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Contact: Melinda Manore
Oregon State University