Friday, November 16, 2012

The science of muscle growth by Jerry Brainum


What makes muscles grow? The obvious answer would be intense exercise and good nutrition, with enough rest and recuperation to maximize size and strength gains. The reason lifting weights produces greater gains in muscle size and strength is that it places more stress on the muscles compared to other types of exercise, such as stretching or aerobics. The muscles respond to the stress through adaptation, involving upgraded muscle protein synthesis.
     That’s the general picture of what causes muscle growth. What happens in the muscle after exercise is a much more complex picture. On a molecular level, muscle growth is a precise symphony involving the immune system, inflammation, hormone release and structural changes. While the knowledge of what’s happening in a muscle during and after training may seem superfluous to anyone except a research scientist, a rudimentary understanding of the internal workings of exercised muscles can tell you what constitutes correct training and rest cycles for gains in size and strength.


                             What Is Muscular Hypertrophy?

      The term hypertrophy means “excessive growth,” and in reference to muscles, that means enlarged muscles usually acquired through exercise. An ongoing debate in physiology is whether muscles get bigger through the addition of new fibers—a process called hyperplasia through which existing muscle fibers split to form new fibers—or whether muscles grow by thickening existing fibers. The fiber-thickening scenario is the generally accepted view.
      Some studies comparing world-class bodybuilders to untrained college students showed that both groups’ muscle fibers had similar dimensions when viewed under a microscope, though the bodybuilders clearly had much larger muscles. Later studies showed that the bodybuilders had far more muscle fibers than untrained college students. The speculation is that years of intense, heavy training promote hyperplasia of muscle fibers.
      Muscle size is related to the cross-sectional area of muscle fibers, or their thickness. As the muscle fiber thickens from a compensation effect induced by heavy exercise, the muscle gets bigger and stronger. Big muscles aren’t always stronger muscles, however. What determines muscle strength is a combination of factors, including favorable leverage and connective tissue. Most important is the increase in muscle contractile proteins, specifically actin and myosin. Some pathological conditions feature large but, paradoxically, weak muscles. An example is acromegaly, usually the result of a small tumor in the anterior pituitary gland that causes the release of huge amounts of growth hormone. People suffering from the disease from an early age wind up very tall, with larger but weaker muscles.
       Indeed, the majority of studies examining the athletic use of growth hormone injections conclude that the drug promotes larger muscle size but without an accompanying increase in strength. GH promotes connective tissue increase in muscle but doesn’t affect the muscle contractile proteins that are the cornerstone of muscular strength.

                      Satellite Cells: The Inner Space of Muscles


     Satellite cells are so named because of their location on the outer surface of the muscle fibers, between the muscle cell membrane, or sarcolemma, and uppermost layer of the basement membrane, or basal lamina. Satellite cells are muscle precursors, or a type of stem cell, that usually lie dormant outside existing muscle fibers. They become activated when any form of trauma, such as damage or injury, occurs to a muscle fiber.1 Resistance exercise, as exemplified by weight training, causes damage to muscle fibers, which deal with it by marshaling adaptation mechanisms, the most significant being activation of satellite cells.
     The damage causes satellite cells to multiply, and various other factors, as we’ll see, cause them to migrate toward the injured area. The satellite cells then fuse to the injured area, while adding a nucleus to the existing fiber, which aids the regeneration process. That doesn’t add new muscle fibers but instead leads to an increase in the amounts of contractile proteins—the actin and myosin—within the fiber. The net effect is muscular growth and strength. The process peaks at 48 hours but continues for four days after the initial trauma (exercise) occurs. That’s why you need time to let a muscle recover after a training session.
      Two main types of muscle fibers are found in humans. The first are known as type 1, or slow-twitch, fibers, also called endurance fibers because of their capacity for extended exercise, such as long-distance running. The other type of muscle fiber, type 2, or fast-twitch, are much larger than the type 1 fibers. They have less endurance but can exert more force, an effect thought to be related to their having a larger nerve supply. Type 2 fibers are most amenable to gains in muscular size and strength, so you’d think they’d have a larger supply of satellite cells around them. In fact, the type 1 fibers have five to six times more, which may reflect their greater blood and capillary supply. (Some studies, however, show an equal number of satellite cells in both types.)
     Another reason for the plethora of satellite cells in type 1 fibers is that they’re used more frequently than type 2s. Muscles function through an orderly recruitment system, and the body attempts to husband its limited energy by activating only enough muscle to do the required task. The first fibers recruited are type 1s, and so they’re subject to a greater rate of injury than the type 2s. As type 1 fibers become fatigued or get stressed by mass or weight, the brain recruits the type 2 muscle fibers. That explains why you need to lift heavy to make maximum gains in the gym. Lifting light weights for higher reps recruits the type 1 fibers, which, as noted, are less likely to get bigger and stronger.
       Most people over age 40 will tell you that it’s harder for them to make significant gains in muscle size, even with regular training. One reason is a relative lack of testosterone, a hormone required for building muscle. The level of testosterone that physicians call “normal” is okay for everyday life, but having a blood testosterone level lower than 300 makes gains in the gym unlikely at best.
     Another reason for the slowdown of muscle gain with age is a loss of neuromuscular efficiency: The muscles become less responsive to the cues from the brain. Without the optimal level of nerve force, a muscle cannot contract as forcefully, and the net effect is a loss of speed, size and strength. Lessened nerve force is usually the reason illustrious athletic careers end. The muscles may still be in relatively good shape, but the response systems are delayed.
     Those over 40 also find that it takes longer to recover from training sessions. Connective tissue, such as ligaments and tendons, has a far poorer blood supply than muscles, which is why connective tissue injuries take longer to heal. With age such tissues get dryer, leading to an even longer recuperation time. Since connective tissue plays a role in muscle strength, if you attempt to train too much or too frequently, you won’t make any gains and will feel overtrained.
      People 40 and older often have fewer satellite cells than younger people—40 percent less relative to the total number of muscle nuclei. Since you need satellite cells to repair damaged muscle, the significance of the loss is obvious; however, it may not be as extreme in those with a long history of training. One study of powerlifters found that the satellite cell content of their trapezius muscles was 70 percent higher than that of nonexercising subjects. 2  The study also featured powerlifters who were taking anabolic steroids, and their level of satellite cells was similar to that of the “clean” lifters.
     Recent studies show that while heavy resistance exercise is the best way to recruit and activate satellite cells, endurance exercise can also increase satellite cell activity. A study of older men involved in endurance exercise without weight training showed that they had a 29 percent increase in satellite cell activity.3 What ultimately determines satellite cell activation is the extent of muscle fiber damage. As you might expect, satellite cell numbers decrease—gradually but regularly—when training ceases. Training enables satellite cells to constantly renew themselves.

                           What Stimulates Satellite Cells?


    Clearly, exercise activates satellite cells. Other factors help maximize the effect. The initial localized inflammation is necessary for containing and repairing the damage, as well as attracting the immune cells, or macrophages, that sweep the area of accumulated muscle waste products. The macrophages secrete cytokines, which are messenger chemicals that signal the release of various growth factors. Cytokines also promote the entry of other immune cells into the area of muscle fiber damage, including lymphocytes, neutrophils and monocytes.
    The cytokines involved in muscle repair include interleukin-1, interleukin-6 and tumor necrosis factor. Other initial inflammatory substances that are vital for the process are prostaglandins, which are hormonelike chemicals made from dietary fat. In particular, prostaglandin F2a, derived from arachidonic acid, is pivotal in muscle protein synthesis. The importance of the initial inflammation is illustrated by recent studies showing that when you take an anti-inflammatory drug following training, muscle repair and muscle protein synthesis are inhibited. Fortunately, aging doesn’t seem to have any effect on the prostaglandin response to training.4


                                 The Muscle Growth Factors


     Various growth factors and hormones also are directly involved in the repair and anabolic processes within exercised muscle. Some are used in drug form for athletic and bodybuilding purposes.
                                        
                                          Insulinlike growth factor 1

    IGF-1 is produced both systemically and locally in muscle. It’s a string of amino acids in a specific sequence. Human growth hormone stimulates the production of IGF-1 in the liver, and IGF-1 activity is considered the source of most of the anabolic effects associated with growth hormone.
     In muscle, IGF-1 promotes the activity of satellite cells.5 It splits into two variants, the other being mechano growth factor. MGF is considered far more potent than localized IGF-1 in muscle.6 It replenishes the pool of muscle satellite cells, and a lack of MGF explains why older people cannot efficiently activate their satellite cells after exercise. Interestingly, when older men are given growth hormone and then lift weights, their bodies produce increased levels of MGF, leading to muscular gains. The growth hormone does that because it increases IGF-1, which then produces MGF.
     Studies of animals injected with MGF show gains of 25 percent in muscle fiber size after only three weeks. In contrast, using gene therapy to deliver IGF-1 genes directly into a muscle resulted in a 15 percent muscle size increase after four months.
     Research like that has two implications. The first is that gene therapy involving upgraded local production of IGF-1 or, preferably, MGF dramatically offsets the loss of muscle size and strength common with aging, so it may be of use in treating various neuromuscular disorders. The second is that MGF is a prime candidate for future athletic doping use. Already, rumors published on the Internet indicate that some athletes may be using MGF, although how and whether they actually got a still experimental drug is open to question.
Besides activating satellite cells, IGF-1 sets off so-called downstream growth pathways, such as the Akt, mTOR and P70 signaling pathways, all of which are involved in muscle protein synthesis.7 You may have read recent ads touting products that “turn on the genetic muscle machinery.” They’re based on the idea that oral intake of certain nutrients, such as branched-chain amino acids, can activate downstream growth pathways and overcome age deficits.8

                                              Hepatocyte growth factor


So named because its growth-promoting effects were originally observed in liver tissue, HGF is activated by muscle injury and is a potent stimulant to satellite cell activity. In one study HGF directly injected into the site of muscle injury led to a 300 percent increase in satellite cell activity.9
     Its release in injured muscle is instigated by nitric oxide, explaining one way in which NO promotes muscular growth. Inhibiting the release of NO also leads to a blockage of HGF release.
                                                
                                                 Fibroblast growth factor

FGF increases the proliferation of satellite cells following injury to muscle fibers. Although several FGFs exist, one in particular, FGF-6, is expressed specifically in muscle and is not upregulated during regeneration.11
                                 The Hormonal Effect


Various anabolic hormones, including growth hormone, IGF-1, testosterone and insulin, all play vital roles in promoting muscular size and strength gains.
1) Growth hormone
As noted, most of the anabolic effects of GH are attributed to the stimulation of IGF-1 promoted by GH release. The IGF-1 produced in muscle splits into two variants, the more potent being MGF. IGF-1 is likely the most potent growth factor in relation to satellite cells, since it’s involved in all three processes of satellite cells: activation, proliferation and differentiation.
     Studies show that most of the gains attributed to GH use consist of water retention and connective tissue, with no effect on muscle contractile proteins. On the other hand, GH’s effects in maintaining the integrity and healing ability of connective tissue is beyond debate, which would mean that it’s still useful to athletes. In addition, combining weights with GH appears to increase the selective release of MGF, which is without question anabolic in muscle. MGF is potent enough to restore muscle gains in older people, indicating a use for GH until MGF gene therapy is perfected.
Another thing to consider is that GH appears to promote the use of bodyfat as an energy source while sparing muscle glycogen reserves. That associates it with a beneficial effect on body composition.
2) Testosterone
       Test and its synthetic versions (known as anabolic steroids) is the primary hormone associated with increased muscle size to most people. Some recent studies show that testosterone directly activates satellite cells, which explains a large part of its anabolic effect.12 That makes sense, since satellite cells are known to produce androgen receptors, which interact with testosterone.13
In animals and humans, testosterone increases the number of satellite cells in muscle. It also interacts with growth hormone and IGF-1, triggering the release of local IGF-1 in muscle. In fact, testosterone appears to make muscle cells more responsive to the effects of IGF-1, which could explain why some athletes stack it with growth hormone and IGF-1.
     The importance of testosterone in gaining muscular size and strength is illustrated by a new study.14 Twenty-two young men, all of whom had some minor experience in weight training, were divided into groups. One group got a drug called goserelin (3.6 milligrams), and the other got a placebo. The drug inhibits gonadotropin-releasing hormone in the hypothalamus, which turns off the body’s testosterone production. The subjects got it subcutaneously, or under the skin, every four weeks for 12 weeks. Both groups engaged in strength training for eight weeks.
     The drug suppressed both total and free testosterone in the treated group to the extent that the subjects’ testosterone levels were 10 percent below normal. Those in the placebo group—who didn’t get the active drug—made significant gains. Those in the drug group made no gains whatsoever in muscular size and strength. Even worse: They showed an increase in fat mass.
    The lack of testosterone in the drug group led to a depression in IGF-1, which in turn led to decreased muscle repair due to satellite cell depression. Testosterone also offsets the effects of cortisol, a catabolic adrenal hormone produced during exercise. Having a metabolic profile that knocks out big T while leaving the effects of cortisol unchecked inevitably leads to no muscle gains coupled with increased bodyfat, especially in the trunk.
    Interestingly, two subjects in the drug group showed extreme increases in lean body mass, despite having low testosterone levels. The authors explain the apparent anomaly by noting that the adrenal glands produce 10 percent of androgen in men, and that would not be suppressed by the drug used in the study, which acts only on the pituitary gland to prevent the release of luteinizing hormone. IGF-1, MGF and other muscle growth factors may not have been affected in these particular young men, but they can be considered an exception to the rule, since the study clearly shows that a lack of sufficient testosterone does prevent muscle gains in most people.





                       The Anti-Growth Factors: Myostatin and Cortisol


Some substances that inhibit muscle growth also play a role in how fast you make gains. The most familiar of them is cortisol.
      Cortisol is considered a stress hormone, since any type of stress provides a stimulus for its release from the cortex portion of the adrenal glands. The release of cortisol is governed by a biochemical cascade. First, stress is perceived in the brain in the hypothalamus, which directly interacts with the nervous system. The hypothalamus then releases corticotropin-releasing hormone, which travels in the brain’s portal blood system to the pituitary gland. Upon arrival, CRF stimulates the synthesis and release of ACTH, which then travels in the blood to the adrenal glands, where it dictates the synthesis and release of cortisol.
    Cortisol has acquired an unsavory reputation as the body’s primary catabolic hormone. The constant stress of everyday life, including the stress of intense exercise, leads cortisol to have an overkill effect. If the level of cortisol exceeds that of its anabolic opposites GH and testosterone, a catabolic state results, leading to a loss of muscle.
      Excess cortisol promotes fat deposition in the trunk, though that is more often seen in pathologic excesses of cortisol, as occurs with Cushing’s disease. In normal instances, cortisol encourages the use of fat as an energy source, particularly after exercise.
     Cortisol is also a potent immunosuppressive and anti-inflammatory mediator—most apparent when certain drugs are used that suppress cortisol release. Athletes who resort to such drugs often report severe joint pain, the result of insufficient anti-inflammatory activity.
   The good news is that it’s not hard to control cortisol release through nutrition. Just taking in carbs during and after training significantly curtails its catabolic effects. Using a supplement rich in branched-chain amino acids will blunt or prevent them, as will the amino acid glutamine. A recently published study showed that glutamine specifically blocked cortisol’s catabolic effects in muscle by preventing a cortisol-promoted increase in myostatin.15
      Myostatin is a protein made up of 375 amino acids.16 It was initially identified by a group at the Johns Hopkins Medical center in Baltimore in 1997. Researchers noticed that mice who lacked the genes to produce myostatin were 30 percent heavier than normal mice, and the extra weight consisted entirely of muscle. That effect was also observed in double-muscled cattle, with the animals having mutations in the myostatin gene that caused them to have huge, defined muscle. In 2004 a report emerged of a human baby born without myostatin genes who was also noticeably stronger and more muscular than other children.
Myostatin does its dirty work in muscles—against IGF-1 and other muscle growth factors—by inhibiting the proliferation and differentiation of satellite cells. Several top pro bodybuilders are said to have mutant genes that make them produce less myostatin than normal. Such people would be far more responsive to training, even without anabolic steroids and other drugs.
    Myostatin and cortisol appear to interact, in that they increase each other’s levels. Diseases entailing catabolic states, such as certain forms of cancer and HIV, are characterized by higher levels of both hormones.
      Most but not all studies show that weight training lowers myostatin.17, 18, 19 One experiment also showed that the effect was accentuated by the use of a high-quality protein supplement. Excess aerobic exercise (more than 60 minutes in one session) will increase both cortisol and myostatin.
     A few years ago some supplement companies attempted to sell a pricey myostatin blocker derived from a type of seaweed. While it did block myostatin in the test tube, further trials showed it to be ineffective in the human body. Subsequently, the researchers who discovered myostatin announced the production of a drug that was effective in the body, promoting a 60 percent increase in animal muscle growth. Another company, Wyeth Pharmacueticals, already has an artificial antibody drug (MYO-029) that blocks myostatin in the human body, intended for the treatment of muscular dystrophy. No doubt the drugs will eventually trickle down into athletic use, and the results should be interesting.
     The factors affecting muscle growth and strength gains are complex and not yet fully understood. What is known and accepted, however, is that the long-held rules of bodybuilding—proper nutrition, rest and judicious levels of exercise—will do the most to trigger the internal events that build muscle.

References
1 Kadi, F., et al. (2005). The behavior of satellite cells in response to exercise: what have we learned from the human studies? Eur J Physiol. 451:319-27.
2 Kadi, F., et al. (1999). Effects of anabolic steroids on the muscle cells of strength-trained athletes.Med Sci Sports Exerc. 31:1528-34.
3 Charifi, N., et al. (2003). Effects of endurance training on satellite cell frequency in skeletal muscle of old men. Muscle Nerve. 28:87-92.
4 Trappe, T., et al. (2006). Effects of age and resistance exercise on skeletal muscle interstitial prostaglandin F2a. Prostag Leukot Ess Fatty Acids. 74:175-81.
5 Charge, S., et al. (2004). Cellular and molecular regulation of muscle regeneration. Physiol Rev. 84:209-238.
6 Goldspink, G. (2005). Research on mechano growth factor: Its potential for optimising physical training as well as misuse in doping. Br Sports Med. 39:787-88.
7 Guttridge, D.C. (2004). Signaling pathways weigh in on decisions to make or break skeletal muscle. Curr Opin Clin Nutr Metab Care. 7:443-50.
8 Proud, C.G. (2002). Regulation of mammalian translation factors by nutrients. Eur J Biochem. 269:5338-5349.
9 Allen, R.E., et al. (1995). Hepatocyte growth factor activates quiescent skeletal muscle satellite cells in vitro. J Cell Physiol. 165:307-12.
10 Anderson, J.E. (2000). A role for nitric oxide in muscle repair: Nitric oxide-mediated activation of muscle satellite cells. Mol Biol Cell. 11:1859-74.
11 Scime, A., et al. (2006). Anabolic potential and regulation of the skeletal muscle satellite cell populations. Curr Opin Clin Nutr Metabolic Care. 9:214-219.
12 Sinha-Hikim, I., et al. (2003). Testosterone-induced muscle hypertrophy is associated with an increase in satellite cell number in healthy, young men. Am J Physiol Endocrinol Metab. 285:E197-E205.
13 Chen, Y., et al. (2005). Androgen regulation of satellite cell function. J Endocrin. 186:21-31.
14 Kvorning, T., et al. (2006). Suppression of endogenous testosterone production attenuates the response to strength training: A randomized, placebo-controlled and blinded intervention study. Am J Physiol Endocrin Metab. 291:E325-E332.
15 Salchian, B., et al. (2006). The effect of glutamine on prevention of glucocorticoid-induced skeletal muscle atrophy is associated with myostatin suppression. Metabolism. 55:1239-47.
16 Gonzalez-Cadavid, N.F., et al. (2004). Role of myostatin in metabolism. Curr Opin Nutr Metab Care. 7:451-457.
17 Roth, S.M., et al. (2003). Myostatin gene expression is reduced in humans with heavy resistance strength training: a brief communication. Ex Biol. 228:706-09.
18 Walker, K.S., et al. (2004). Resistance training alters plasma myostatin but not IGF-1 in healthy men. Med Sci Sports Exerc. 36:787-93.
19 Willoughby, D.S. (2004). Effects of heavy resistance training on myostatin mRNA and protein expression. Med Sci Sports Exerc. 36:574-82.  

   

©,2015 Jerry Brainum. Any reprinting in any type of media, including electronic and foreign is expressly prohibited


Have you been ripped off  by supplement makers whose products don’t work as advertised? Want to know the truth about them? Check out Jerry Brainum's book Natural Anabolics, available at JerryBrainum.com.

 

The Applied Ergogenics blog is a collection of articles written and published by Jerry Brainum over the past 20 years. These articles have appeared in Muscle and Fitness, Ironman, and other magazines. Many of the posts on the blog are original articles, having appeared here for the first time. For Jerry’s most recent articles, which are far more in depth than anything that appears on this blog site, please subscribe to his Applied Metabolics Newsletter, at www.appliedmetabolics.com. This newsletter, which is more correctly referred to as a monthly e-book, since its average length is 35 to 40 pages, contains the latest findings about nutrition, exercise science, fat-loss, anti-aging, ergogenic aids, food supplements, and other topics. For 33 cents a day you get the benefit of Jerry’s 53 years of writing and intense study of all matters pertaining to fitness,health, bodybuilding, and disease prevention.

 

See Jerry's book at  http://www.jerrybrainum.com

 

Want more evidence-based information on exercise science, nutrition and food supplements, ergogenic aids, and anti-aging research? Check out Applied Metabolics Newsletter at www.appliedmetabolics.com

 


Friday, November 9, 2012

Muscle Fiber Fact vs. Fiction by Jerry Brainum


New Findings Reveal the Truth Behind Muscle Growth

It’s no secret that having favorable genetics gives you a significant head start on bodybuilding success. Muscle fibers can be among those genetic advantages. Longer muscles, which have more muscle fibers, can produce greater rates of muscular growth. The number of fibers is determined at birth, although the types of fibers may be subject to change to a certain extent. Take, for example, the calf muscles. Having high calves usually means you have fewer muscle fibers in your calves, which translates into less potential for growth. That doesn’t preclude muscle growth; it just means that the odds of obtaining massive calves are stacked against you.
      Human muscle fibers come in three main types:
1) Type 1, or slow-twitch, are smaller and generally more suited to endurance, or aerobic, activity.
2) Type 2A are intermediate, showing some of the characteristics of types 1 and 2B fibers.
3) Type 2B are most the amenable to growth. They’re the “strength and size” fibers. They have a low resistance to fatigue, as they lack the extensive blood vessels and mitochondria present in type 1 fibers. They work mainly through anaerobic metabolism. On the other hand, type 2B fibers have the thickest motor neuron connections, which means they produce greater force than the other kinds of fibers.
Muscle fibers are recruited in a certain order, with type 1 fibers being activated first, followed in order by the type 2As and 2Bs. Most exercise physiology textbooks say that type 2B fibers can be recruited only by heavy weight and high intensity. For years bodybuilders have been told that they need heavy weights and high intensity to achieve gains in muscle size and strength. That’s because they need to activate type 2B muscle fibers.
      Years ago a study was published that compared the muscle fibers in elite competitive bodybuilders to those of unathletic physical education students. Because the bodybuilders had arm circumferences that averaged 19 to 20 inches, the researchers fully expected the bodybuilders to show far larger muscle fibers than the students. After all, muscle growth involves a thickening of muscle fibers as a result of intense exercise, which causes increased muscle protein synthesis. Yet when viewed under the microscope, the muscle fibers of the massive bodybuilders weren’t all that different from those of the far less muscular students. How could that be?
       The researchers suggested that years of heavy and intense training had encouraged a process called hyperplasia, which is a splitting of muscle fibers. So while the bodybuilders’ individual muscle fibers weren’t larger than normal, they’d produced far more of them. As the fibers themselves weren’t counted, the hyperplasia hypothesis remained speculative, but how else to explain the notable disparity in muscle size between the bodybuilders and the students?
      A more recent study also produced a number of surprises. Once again, champion bodybuilders were compared to ordinary college students. The bodybuilders all consumed a high-protein diet, averaging 200 to 220 grams daily, and none had used anabolic steroids for two years prior to the study—or so they said. They trained regularly four to six times a week, for three to four hours at each session. The muscles examined in the study were the front thighs, and the bodybuilders’ leg routines averaged two sessions a week. They did 12 sets of 10 to 20 reps, using 70 to 90 percent of one-rep-maximum weights.
Note that the study examined single muscle fibers. Since the type 2B fibers are the muscle fibers most likely to grow, it stands to reason that the bodybuilders in the study would have an abundance of such fibers, or at least more of them than the other kinds of muscle fibers. The reality was that they showed a higher portion of types 1 and 2A fibers, with a near complete absence of type 2Bs. How could that be?
       Training. Typical bodybuilding training isn’t characterized by using maximum weight for six reps or fewer but instead involves higher reps, less rest time between sets and high training intensity. It turns out that this style of training favors the transformation of fibers into type 2As, which have some of the characteristics of both strength and endurance, exactly matching the way most bodybuilders train. The body adapts by spurring the development of the muscle fibers most efficient for the purpose: type 2A fibers.
      While type 2Bs have low fatigue resistance, 2As have intermediate fatigue resistance. Type 2B fibers last less than a minute before fatigue sets in, while 2As can go for five minutes. One reason is that 2A fibers contain more mitochondria—the cell’s energy factory—than type 2Bs and are more efficient at using oxygen, thus making fuel more available.
     As for type 2Bs, the authors say that in bodybuilders they work more or less as reserve fibers. When recruited during exercise, they convert into the type 2A fibers that are so abundant in bodybuilders. Interestingly, high numbers of type 2B fibers are found in obese women and in those with spinal cord injuries, in the latter case likely as the body’s way of compensating for the injury.
     One limitation of the study, the authors suggest, is that the bodybuilders might have been born with greater numbers of type 2 muscle fibers, thus having a genetic predisposition toward more muscle growth.
What does it all mean in a practical sense? More than anything that bodybuilders’ knowledge is empirical. They’ve discovered from years of experience that using weights that give them a range of eight to 12 reps yields the most muscle growth. Now we know why: Because of the middle-of-the-road type 2A fibers, which have characteristics of both aerobic and anaerobic muscle fibers. So for maximum training progress it’s best to gear your training for the type 2As. That doesn’t mean it’s useless to use heavy weights that give you six reps or fewer per set. They’re great for strengthening connective tissue and for activating the type 2B fibers that will transform into 2A fibers with continued training.

Kesiidis, N., et al. (2008). Myosin heavy chain isoform distribution in single fibers of bodybuilders. Eur J Appl Physiol. 103(5):579-83.

  
©,2015 Jerry Brainum. Any reprinting in any type of media, including electronic and foreign is expressly prohibited

Have you been ripped off  by supplement makers whose products don’t work as advertised? Want to know the truth about them? Check out Jerry Brainum's book Natural Anabolics, available at JerryBrainum.com.

 

The Applied Ergogenics blog is a collection of articles written and published by Jerry Brainum over the past 20 years. These articles have appeared in Muscle and Fitness, Ironman, and other magazines. Many of the posts on the blog are original articles, having appeared here for the first time. For Jerry’s most recent articles, which are far more in depth than anything that appears on this blog site, please subscribe to his Applied Metabolics Newsletter, at www.appliedmetabolics.com. This newsletter, which is more correctly referred to as a monthly e-book, since its average length is 35 to 40 pages, contains the latest findings about nutrition, exercise science, fat-loss, anti-aging, ergogenic aids, food supplements, and other topics. For 33 cents a day you get the benefit of Jerry’s 53 years of writing and intense study of all matters pertaining to fitness,health, bodybuilding, and disease prevention.

 

See Jerry's book at  http://www.jerrybrainum.com

 

Want more evidence-based information on exercise science, nutrition and food supplements, ergogenic aids, and anti-aging research? Check out Applied Metabolics Newsletter at www.appliedmetabolics.com

 

Sunday, November 4, 2012

Arnold's rules for success by Jerry Brainum


It would be hard to argue that Arnold Schwarzenegger has had a very successful life thus far.Yes, he's had a few bumps in the road, such as the disclosure that he had a child out of wedlock.But as he has done with most other problems in his life, Arnold appears to have accepted this "mistake," as he puts it, and moved on. In his recently published autobiography, Total Recall, Arnold recounts his life in exhaustive detail. Perhaps the most interesting part of the book, however, is the chapter called "Arnold's Rules." This chapter is a synopsis of how Arnold became successful. What are these rules, and are they applicable to all of us? The rules are as follows:

1) Turn your liabilities into assets-Arnold mentions how he used what would normally be barriers to success in the film world, namely his size and accent, and instead turned them in unique traits that aided his climb to the top in the film business.
2) When someone tells you no, you should hear yes-I can testify that this is the very essence of Arnold's success. No matter what the odds were against him, Arnold turned a deaf ear. He was like the real-life version of the Terminator: an unstoppable force that would not rest until it got what it wanted.
3) Never follow the crowd, go where it's empty-By this he means, become a non-conformist. Don't do what everyone else does. Do what you want to do (within reason).
4) No matter what you do in life, selling is part of it-We are always selling ourselves, one way or the other. When we meet a prospective romantic partner, we are in a definite sales mode. Arnold's philosophy is that we have to sell ourselves to succeed, and cannot passively wait for success to come to us.
5) Never let pride get in your way-the anecdote that Arnold relates in the book for this doesn't make sense. So I guess in that respect, he didn't let pride get in his way!
6) Don't overthink-Arnold thinks that many people with extensive knowledge overanalyze things, and thus talk themselves out of possibly lucrative opportunities.He suggests that if something appears promising, it's better to just forge ahead and not think too deeply about it. Such a plan can either prove very successful, or lead to utter disaster.
7) Forget Plan B-This is similar to the previous rule. Just do it, and don't worry about it. Don't even think about alternative ideas. Again, this is either sage advice, or a recipe for disaster. In actuality, Arnold often consulted with knowledgeable people in fields that he was interested in before proceeding.
8) You can use outrageous humor to settle a score- One wonders if he has tried this yet with his wife.
9) The day has 24 hours- Arnold says that you should not waste your time on unproductive activity. He then goes on the mention how he trained 5 hours a day, attended school, worked at construction, all of which would have precluded getting any sleep.
10) Reps, reps, reps- Arnold confirms the notion that becoming a master at any task requires constant practice. The usual statement in this regard is that it takes 10,000 hours of practice to become a master at anything.
11) Don't blame your parents- Arnold discusses in the book the stern discipline that was imparted on him by his father. He considers that an asset, since he turned it into a lifelong drive to succeed.
12) Change takes big balls-True success requires a large element of risk.
13) Take care of your body and your mind.
14)  Stay hungry-When you've achieved success in one endeavor, move on to another. Never be satisfied, but always seek even more success in several fields.

I would add one more rule:

15) Never fool around with the hired help.

©,2012 Jerry Brainum. Any reprinting in any type of media, including electronic and foreign is expressly prohibited

Have you been ripped off  by supplement makers whose products don’t work as advertised? Want to know the truth about them? Check out Jerry Brainum's book Natural Anabolics, available at JerryBrainum.com.

 

The Applied Ergogenics blog is a collection of articles written and published by Jerry Brainum over the past 20 years. These articles have appeared in Muscle and Fitness, Ironman, and other magazines. Many of the posts on the blog are original articles, having appeared here for the first time. For Jerry’s most recent articles, which are far more in depth than anything that appears on this blog site, please subscribe to his Applied Metabolics Newsletter, at www.appliedmetabolics.com. This newsletter, which is more correctly referred to as a monthly e-book, since its average length is 35 to 40 pages, contains the latest findings about nutrition, exercise science, fat-loss, anti-aging, ergogenic aids, food supplements, and other topics. For 33 cents a day you get the benefit of Jerry’s 53 years of writing and intense study of all matters pertaining to fitness,health, bodybuilding, and disease prevention.

 

See Jerry's book at  http://www.jerrybrainum.com

 

Want more evidence-based information on exercise science, nutrition and food supplements, ergogenic aids, and anti-aging research? Check out Applied Metabolics Newsletter at www.appliedmetabolics.com

 

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Friday, November 2, 2012

Creatine Myths Exploded by Jerry Brainum


There’s an old saying that when you’re at the top, someone’s always trying to bring you down. The adage certainly applies to creatine. Since its commercial introduction in 1993, creatine has become one of the most popular bodybuilding supplements, and for good reason. Countless studies prove its effectiveness, the scientific consensus being that it works for 80 percent of its users. The other 20 percent usually eat red meat habitually. Red meat contains high levels of natural creatine, and those who eat it regularly tend to have more creatine stored in their muscles. That’s why they don’t respond as dramatically to the supplement as vegetarians or those who eschew eating meat.
       Along with its commercial success, however, creatine has also been subject to much unfounded criticism. The misinformation is fueled by poorly researched popular media reports about its effects. Indeed, some newspaper and television news features have identified creatine as a steroid. In fact, it’s an amino acid by-product synthesized in the liver, kidney and pancreas from three amino acid precursors: methionine, glycine and arginine. The body produces about one gram of creatine a day, and if you eat meat, you get another gram or two as well. Labeling creatine a drug of any kind is an example of shoddy research.
      Popular media, though, aren’t the sole purveyors of creatine misinformation. Science journals regularly publish alarming reports suggesting a dark future for creatine users. A closer perusal of them usually shows how irrelevant they are for those in good health. It’s like those reports that eating lots of protein is risky for those with kidney failure. There’s zero evidence that either creatine or a high-protein intake is hazardous for people who have normal kidney function.
      Among the side effects attributed to creatine are excess kidney stress, muscular cramps and dehydration. Two recently published studies, however, definitively prove that the claims are false.
The theory is that creatine use promotes a shift of water from extracellular and into intracellular compartments. Critics say that that makes it hard to maintain cooler body temperature and alters electrolyte, or mineral, balance, leading to muscle cramps. Studies that have found muscle cramps and overheating with creatine use have by and large involved athletes training in hot weather, when they may not have been drinking enough water to balance sweating and other fluid loss from the heat and exertion. Other studies show the opposite: Creatine appears to offer significant protection against heat illness, dehydration and muscle cramps. That makes sense because creatine increases total body water, which would protect against dehydration while lowering core body temperature.
      Then there’s the fear that creatine affects kidney function. The primary waste product of creatine metabolism, creatinine, is excreted through the kidneys, and with compromised kidney function, excess creatinine could produce kidney stress. In fact, a primary test of kidney function is called the creatinine-clearance test; in it excess creatinine points to problems with the filtering mechanism in the kidneys. Just because a clinical test uses a particular substance as a marker of bad kidney function, however, doesn’t prove the substance caused the problem.
      One study, which reviewed the literature about the effects of creatine in relation to muscle cramps and dehydration, cited a 1998 case study published in the Lancet describing a 25-year-old man who experienced a decline in kidney function after taking 20 grams of creatine a day. Complicating the report was the fact that the man had kidney disease. When he stopped using the creatine, his symptoms abated, leading the authors to suggest that creatine was toxic to kidney function. A French newspaper reported that three days after the review was published, but it totally overlooked the fact that the man already had serious kidney disease. In any case, taking 20 grams of creatine after you’ve done a typical creatine-loading phase of five days is just plain foolish, as nearly all of the creatine is rapidly excreted once the muscles are loaded.
     Besides questionable human studies pointing to creatine-induced renal stress, a number of animal studies have been used to bolster that criticism, but those, too, are red herrings, since creatine isn’t a normal nutrient for many animal species and may not even be absorbed. For example, creatine intake causes chronic hepatitis in mice but not in rats. In contrast, humans easily and rapidly absorb it, even though many ads attempt to deny that so they can sell “superior” creatine supplements.
     Complicating the picture is the fact that the creatinine test, the primary test for kidney function, isn’t accurate for those who use creatine, particularly during a loading phase. A recent study compared men, ages 18 to 35, who got either 10 grams of creatine or a placebo daily for three months. The researchers used a newer test of kidney function that measured a serum protein called cystatin C. Cystatin C is regularly filtered in the kidneys and easily reabsorbed, since it has a low molecular weight. A loss of cystatin C is a good indicator of a defect in the glomerular filtration system of the kidneys and isn’t affected by creatine metabolism.
      The study found that, based on monitoring cystatin C excretion, taking in 10 grams of creatine daily for three months had no adverse effects on kidney function. The subjects also participated in aerobic exercise for 40 minutes three times a week. Tests on those in the placebo group showed that the exercise alone improved kidney function. That was attributed to the health-promoting effects of exercise, such as more efficient glucose control, lower blood pressure and a reduction in oxidative stress and bodyfat levels. Significantly, those are the same factors that offer lifelong kidney protection, suggesting that regular exercise is one of the best things you can do to preserve kidney function.

References
Dalbo, V.J., et al. (2008). Putting the myth of creatine supplementation leading to muscle cramps and dehydration to rest. Brit J Sports Med. 2008;42:567-73.


©,2013 Jerry Brainum. Any reprinting in any type of media, including electronic and foreign is expressly prohibited. 

Have you been ripped off by supplement makers whose products don’t work as advertised? Want to know the truth about them? Check out Jerry Brainum's book Natural Anabolics, available at JerryBrainum.com

 
 

The Applied Ergogenics blog is a collection of articles written and published by Jerry Brainum over the past 20 years. These articles have appeared in Muscle and Fitness, Ironman, and other magazines. Many of the posts on the blog are original articles, having appeared here for the first time. For Jerry’s most recent articles, which are far more in depth than anything that appears on this blog site, please subscribe to his Applied Metabolics Newsletter, at www.appliedmetabolics.com. This newsletter, which is more correctly referred to as a monthly e-book, since its average length is 35 to 40 pages, contains the latest findings about nutrition, exercise science, fat-loss, anti-aging, ergogenic aids, food supplements, and other topics. For 33 cents a day you get the benefit of Jerry’s 53 years of writing and intense study of all matters pertaining to fitness,health, bodybuilding, and disease prevention.

 

See Jerry's book at  http://www.jerrybrainum.com

 

Want more evidence-based information on exercise science, nutrition and food supplements, ergogenic aids, and anti-aging research? Check out Applied Metabolics Newsletter at www.appliedmetabolics.com