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Muscle Science Roundup

Unlike conventional aerobics, which increases resting metabolic rate only when you’re actually exercising, interval training leads to a sustained rise in resting metabolic rate.


It’s the end of 2008, an Olympic year in sports as well as in the science lab. There were some gold-medal discoveries as a result of research conducted this year and at the tail end of 2007, most of them reported in IM's pages by our consummate science scribe, Jerry Brainum. Let’s take a look at the specific findings that can help you get bigger and leaner in 2009.

Micronutrients for Mass

While this study involved women, it affects anyone who trains for muscle and strength. Thirty-five young women who were considered somewhat calcium deficient were put on a weight-training program. They were divided into three groups: a group that ate a serving of fat-free yogurt after training; a group that drank a commercial sports drink containing no calcium or vitamin D, just carbs and protein; and a group that drank a beverage containing only carbs—25 grams. All of those postworkout “meals” contained the same number of calories, 100.

While the groups were getting similar amounts of protein, those in the yogurt group showed the greatest lean-mass gains. All of the women lost bodyfat during the study, but those in the yogurt group lost the most. They also achieved the greatest strength gains.

The researchers believe that the more significant loss of bodyfat and gains in muscle and strength were caused by the additional calcium and vitamin D provided by the yogurt.

Application: Get plenty of calcium and vitamin D to build muscle and burn fat. That’s especially important if you’re dieting—make sure your plan doesn’t leave you deficient in those nutrients.

 

White, K., et al. (2007). Yogurt consumption during resistance training increases muscle mass and strength in young women. Presented at the 2007 International Society of Sports Nutrition conference and expo, Las Vegas, Nevada.

Fatigue Blaster to Grow Faster

Fifteen male athletes got either 4.8 grams a day of beta-alanine or a placebo. Their performance was judged by isokinetic testing—five bouts of 30 maximum voluntary knee extensions. 

As high-level athletes they already had greater-than-normal muscle carnosine, but beta-alanine supplementation increased the carnosine in both the soleus (47 percent) and the gastrocnemius (37 percent). Those in the placebo group showed stable carnosine in the soleus, while the content in the gastrocnemius rose by 16 percent with exercise alone. Dynamic knee extension torque during the fourth and fifth bouts was significantly improved in the beta-alanine group but not in the placebo group. 

From a bodybuilding standpoint, the study suggests that beta-alanine’s maximum effects would occur during the later sets. That makes sense, since the mechanism of beta-alanine increases muscle carnosine, and carnosine is a major intramuscular buffer that neutralizes the excess acid produced by muscle fatigue. Naturally, you’d be more prone to that during the later sets.

Application: Use about four grams of beta-alanine a day to delay fatigue and help you train harder to get more muscle-growth stimulation. The implication is that there’s no ceiling on using beta-alanine, as there is with creatine. So no matter how great an athlete or bodybuilder you are, there’s always room for more carnosine in your muscles. In contrast, once muscles are filled with creatine, any excess is simply excreted from the body. [Note: Red Dragon is a pure beta-alanine supplement.]

 

Derave, W., et al. (2007). Beta-alanine supplementation augments muscle carnosine content and attenuates fatigue during repeated isokinetic contraction bouts in trained sprinters. J Appl Physiol. 103:1736-1743.

Stretch for Strength

Thirty-eight college students were randomly assigned to a stretching group and a control group, each consisting of eight men and 11 women. The study lasted 10 weeks and focused on a program of static stretching—assuming a stretch position, then holding for 10 to 30 seconds—made up of various stretches designed to work the lower body, with the subjects stretching for 40 minutes, three times a week. Each subject was measured before and after the study for flexibility, power, strength and strength endurance.

At the conclusion, the subjects in the stretching group showed an average 23.9 percent increase in muscular strength and a 29.5 percent increase in muscular endurance. They also had an average 18.1 percent increase in flexibility. The control subjects, who did no training or stretching, showed zero improvement. 

The study appears to confirm that stretching all by itself increases flexibility, strength, endurance and power. The authors suggest that the improvements in power and endurance in the stretching group are related to the increase in strength that resulted from the extensive stretching sessions.

The gains in power are related to increases in muscle length, which lead to increases in muscle contractile velocity and force generation—all of which equates to more muscle power.

Application: A separate stretching workout can be a good adjunct to weight training for strength increases. Other studies have shown that stretching immediately before weight training can weaken muscles, so stretch after your weight session, or use stretching as a stand-alone workout.

 

Kokkonen, J., et al. (2007). Chronic static stretching improves exercise performance. Med Sci Sports Exer. 39:1825-31.

Creatine Turbocharger

Are you interested in adding to the size and strength effects of creatine? Conjugated linoleic acid may be the creatine turbocharger you’re looking for.

A Canadian study confirmed that the combination of creatine and CLA, along with a protein supplement, synergistically stimulates muscle gains. Fifty-two men and 17 women, average age 22 1/2, were randomly assigned to one of three groups, receiving:

 

1) Protein, consisting of 45 grams a day of whey protein supplement

2) Protein and creatine—36 grams of whey protein and nine grams of creatine daily

3) Protein, creatine, CLA—36 grams of protein, nine grams of creatine and six grams of CLA daily

The supplements were taken during a five-week period of weight training. Those in group 3 had an average 14.3 percent gain in strength on the leg press and bench press compared to 8.5 percent for the other groups. Group 3 also gained more lean tissue than the others.

Application: Try taking five to six grams of CLA along with your creatine, and watch for new size and strength increases.

 

Cornish, S.M., et al. Effect of supplementing with conjugated linoleic acid, creatine monohydrate and whey protein during high-intensity resistance training in young adults. Paper presented at the 2007 meeting of the Canadian Physiological Association in Ottawa.

Intervals for a
Fat-Burning Firestorm

The fat-burning effectiveness of interval aerobic training is evident in the results of a recently published study that featured eight women, including moderately fit women, some who did no exercise and an active soccer player. All in their 20s, they trained every other day for two weeks, performing a high-intensity interval workout on stationary bikes: 10 sets of four-minute high-intensity bursts at an intensity equal to 90 percent of their maximum oxygen intake, alternated with two-minute rest intervals between sets, in which they cycled at low intensity.

The starting point of fitness made no difference in the results. At the end of the study the women had an average increase of 36 percent more fat burned. Their cardiovascular fitness also rose by an impressive 13 percent.

How to explain such rapid results? It turns out that interval training is particularly effective at boosting activity in the portion of cells where fat is burned, or oxidized, and oxygen is used, the mitochondria. The authors noted that the women showed signs of increased mitochondrial volume, as evidenced by a rise in enzymes associated with fat burning and oxygen use. 

The training also increased the activity of a protein that transports fatty acids into the cell, where the fat is burned. Even more impressive was that there was no significant loss of muscle glycogen, pointing to an almost exclusive use of fat as fuel during the exercise. 

Other studies of interval training have found an increase in enzymes required for fat oxidation of 10 to 35 percent after only two weeks. Studies that have compared interval to conventional long, slow, moderate-intensity aerobics show that interval training produces similar beneficial effects but with 90 percent less training volume. One study found similar improvements with 2.5 hours a week of interval work compared with 10.5 hours a week of conventional aerobics.

Unlike conventional aerobics, which increases resting metabolic rate only when you’re actually exercising, interval training leads to a sustained rise in resting metabolic rate. That means you wind up burning more calories at rest, typically calories derived from fat stores. The only other type of exercise known to do that is weight training. The fact that weight training works mainly type 2, or fast-twitch, muscle fibers explains the rise in metabolism, since the repair of damaged fibers induced by weight training leads to biochemical changes that result in a higher resting metabolic rate. Intervals also tap into type 2 fibers during the high-intensity phase, explaining why that style of aerobics—unlike traditional aerobics—also produces a more sustained rise in resting metabolic rate. The slow phase of intervals shifts the focus to type 1, or slow-twitch, muscle fibers, which preferentially burn more fat than type 2 fibers.

Application: Use interval aerobics for maximum fat-burning effects; however, be careful not to do it too close to a leg workout, as intervals also tap into type 2 muscle fibers.

 

Talanian, J.L., et al. (2006). Two weeks of high-intensity aerobic interval training increases the capacity for fat oxidation during exercise in women. J Appl Physiol. 102:1439-1447.

Carnitine Can
Pump You Up

While L-carnitine has several functions in the body, it’s best known for shuttling fat into the portion of cells known as mitochondria. Fat is burned, or oxidized, in the mitochondria in a process called beta-oxidation. Carnitine is essential for that process.

Glycine-propionyl-L-carnitine is a specialized form of carnitine that’s particularly beneficial for heart function. The heart prefers fat as an energy source, and GPLC is used therapeutically to treat heart failure and poor blood circulation. Studies show that GPLC has more affinity for muscle than other forms of L-carnitine, and they suggest that using GPLC may boost exercise efficiency by lowering lactic acid and causing fat to be used more efficiently as an energy source.

Fifteen experienced weight-trained men were given 4.5 grams a day of either GPLC or a placebo. They were also given carbohydrates to promote insulin release, as insulin fuels carnitine uptake into tissues. 

Under normal circumstances nitric oxide release occurs with turbulent blood flow, such as that induced by exercise. NO is synthesized and released in the endothelium, or lining of blood vessels. In that manner, NO inhibits the clumping of blood platelets and expands the diameter of blood vessels. The net effect is increased blood flow and, in the case of bodybuilding exercise, increased muscle pump and delivery of nutrients and oxygen to working muscle.

The study showed that NO release was significantly higher in those who took the GPLC supplement than it was in those who took the placebo. As to how GPLC works in relation to NO, the authors weren’t sure. One theory is that it inhibits an oxidative enzyme that rapidly degrades NO because of an increase in free radicals. Another theory is that GPLC augments the activity of endothelial nitric oxide synthase, the enzyme in the blood vessel walls that produces NO from arginine.

GPLC may be a useful adjunct to NO supplements, since it independently augments NO release and has no known side effects. It provides other benefits, such as increased muscle and heart efficiency, along with lower lactic acid production during intense exercise. In that sense, it would be complementary with beta-alanine, which is mainly used to control the higher acidity levels produced during exercise. GPLC also helps maintain androgen cell receptors, which increases the anabolic efficiency of testosterone. In fact, some pre-inary studies suggest that GPLC may be of use in treating male impotence.

Application: Try a few grams of glycine propionyl-L-carnitine along with your arginine-based nitric oxide precursor for a more powerful vasodilating effect—a.k.a. a full-blown pump with streakng vascularity.

 

Bloomer, R.J., et al. (2007). Glycine propionyl-L-carnitine increases plasma nitrate/nitrite in resistance-trained men. J Int Soc Sports Nutr. 4:22.

Preworkout Growth Hormone Boosters

The amino acid most often linked to growth hormone release is arginine, but the GH picture includes more complex brain chemistry. Growth-hormone-releasing hormone, or GHRH, is released by the hypothalamus, and somatostatin, known as both SST and growth-hormone-inhibiting hormone, is released in the brain and elsewhere in the body. Scientists believe that amino acids stimulate the production of GH by inhibiting the release of SST.

Two recent studies highlight those effects in people engaged in weight training. In one the focus was on melatonin. Thirty young men and 30 young women were randomly given either melatonin supplements in doses of one-half milligram or five milligrams or a placebo. They then did leg presses, seven sets of seven reps, using a weight equal to 85 percent of their one-rep maximums. Blood samples were taken at various intervals to determine hormone and blood responses.

The men who received five milligrams of melatonin experienced an increase of GH release, which was attributed to a blunting of SST. In fact, compared to the men who got the placebo, they had a 157 percent rise in GH prior to training and a 132 percent increase over resting levels after the workout. The response to melatonin was much weaker in women, which was thought to be related to the greater amounts of estrogen in their bodies.

The interesting aspect of the study was that the melatonin-related increase in GH wasn’t entirely due to a blunting of SST. The melatonin-GH connection shows up in other pathways in the body as well.

Another recent study featured 11 weight-trained young men who took either three grams of gamma aminobutyric acid—GABA—or a placebo, followed by either rest or a weight workout. The combination of exercise and GABA led to a 200 percent increase in active GH, possibly attributable to a blunting of SST or a rise in the secretion of growth-hormone-releasing hormone or both.

GABA is made in the brain from glutamic acid. It’s an excitatory neurotransmitter, or brain stimulant. When exposed to specific enzymes and the active form of vitamin B6, however, it converts into the inhibitory form of GABA. You wouldn’t want to supplement with straight glutamic acid, which studies associate with lowering GH when taken before exercise and the production of cortisol and prolactin—not good.

So should you go out and purchase a bundle of melatonin and GABA and await delivery of GH? Well, they both bring on drowsiness, the last thing you want before working out.

Application: Using melatonin or GABA preworkout to encourage growth hormone release may be a feasible experiment, but you may need to drink coffee or take caffeine pills before workouts to counteract drowsiness.

 

Nassar, E., et al. (2007). Effects of a single dose of N-acetyl-5-methoxytryptamine (melatonin) and resistance exercise on the growth hormone/IGF-1 axis in young males and females. J Inter Soc Sports Nutr. 4:14.

Powers, M.B., et al. (2007). Growth hormone isoform responses to GABA ingestion at rest and after exercise. Med Sci Sports Exer. 40:104-110. 

Thermogenic King Beats Ephedrine?

The following is a report from Jose Antonio, Ph.D.:

Would you believe me if I told you that there’s a weight-loss pill that beats the thermogenic crap out of the much-vaunted caffeine-and-ephedrine combination? Well, that’s what I discovered at the fifth annual International Society of Sports Nutrition Conference and Expo in the beautiful Red Rock Hotel in Las Vegas. In a 2008 study performed at the College of New Jersey, scientists were astounded to learn that a potent new fat-burning matrix called Meltdown was more effective than ephedrine. Whoa, Nellie! Can that be true? 

Ten subjects underwent two testing sessions administered in a randomized and double-blind fashion. The volunteers got either three capsules of Meltdown or three capsules of a placebo. They then rested in a semirecumbent position for three hours. Imagine how tough it is to sit still while the ingredients of such a thermogenic cocktail course through your veins! Statistical analysis revealed a significant difference in energy expenditure during the entire three hours; also, there was a greater use of stored fat as energy. According to the investigators, the “results indicate a significant increase in energy expenditure in young, healthy individuals following an acute ingestion of a weight-loss supplement.” Compare that to the caffeine-and-ephedra numbers.

In the classic study by Astrup, et al. (1991), the results were as follows: Over a three-hour period the increase in calories burned was 11, 13 and 23 for 20 milligrams of ephedrine, 200 milligrams of caffeine and 10 milligrams of ephedrine plus 200 milligrams of caffeine, respectively. On the other hand, Meltdown showed a 50-calorie increase. That’s more than 60 percent better than ephedrine plus caffeine. 

Application: You may want to try Meltdown in your fat-burning-supplement rotation for a bigger metabolic kick.

 

Astrup, A., et al. (1991). Thermogenic synergism between ephedrine and caffeine in healthy volunteers: a double-blind, placebo-controlled study. Metabolism. 40(3):323-329.

Tea Off on Bodyfat

A recent study featured 12 young men, average age 26. In the first part they took a capsule containing ingredients equivalent to 3 1/2 cups of green tea three times a day, the last one hour before exercise. Other subjects got a placebo containing corn flour. The exercise consisted of 30 minutes of cycling at an intensity equal to 60 percent of maximum heart rate. In the second part of the study 11 of the men took an oral glucose-tolerance test before and after taking green tea capsules.

Those who took the green tea capsules had a 17 percent greater contribution of fat to energy expenditure during exercise than those who took the placebo. That scale of fat oxidation was over and above what usually occurs during exercise, pointing to a definite green tea effect. The second part of the study showed that green tea increased insulin sensitivity by 13 percent, which reduced the insulin response to a glucose load by 15 percent.

Another study, this one with isolated fat cells, found that green tea can inhibit the development of new fat cells. The mechanism is an inhibition of GPDH, an enzyme, along with the inhibition of PPAR-gamma, a protein that boosts bodyfat. Green tea acts as an oxidant in fat cells—but that’s good because it activates AMPK, a protein that stimulates fat oxidation in muscle during exercise.

Application: Drink green tea for health and to get leaner and/or take a green tea supplement three times a day to augment fat burning.

 

Venables, M.C., et al. (2008). Green tea extract ingestion, fat oxidation, and glucose tolerance in humans. Am J Clin Nutr. 87:778-784.

Seuk-Moon, H., et al. (2007). Inhibitory effect of epigallocatechin-3-gallate on lipid accumulation of 3T3-L1 cells. Obesity. 15:2571-2582.

Arginine Is More Than Just an NO Booster

The amino acid L-arginine is the main ingredient in nitric oxide precursor supplements, but its most overlooked aspect is its effect on muscle protein synthesis. While the branched-chain amino acids, particularly leucine, are most associated with muscle protein synthesis, all essential amino acids are actively involved in the process. Recent evidence shows that arginine mimics many of the effects of BCAAs in regard to muscle protein synthesis.

One recent study used rabbits as subjects. The authors note that under severe catabolic conditions, such as burn injuries, the requirement for arginine rises. Past studies show that arginine greatly aids wound healing. At first the effect was attributed to increased growth hormone release. Later, when arginine was identified as the primary source of NO, the increased blood circulation fostered by NO was thought to be the cornerstone of arginine’s healing effects. The most recent studies indicate that the source of arginine’s healing power is its role in stimulating protein synthesis. BCAAs are involved in the same thing.

The rabbit study involved wounds to the animals’ skin and muscle. One focus was whether the healing effect of arginine increased NO release in the wound area. The researchers gave the animals a chemical that blocks NO production. That had no effect on the increased muscle protein synthesis that occurred after the animals were given arginine, although the blood flow to the wounded area was markedly reduced, confirming that NO was blocked. The researchers also ruled out increased insulin release, since plasma glucose didn’t drop, as would have occurred with upgraded insulin release. What they found was that arginine stimulated the movement of amino acids from blood into muscle. That increased amino acid availability and, consequently, muscle protein synthesis.

Application: Arginine spurs muscle protein synthesis independent of NO. Use supplemental arginine for vasodilation and ancillary anabolic effects, like enhanced protein synthesis.

—Compiled by Steve Holman

 

Zhang, X.J., et al. (2008). The anabolic effect of arginine on proteins in skin wound and muscle is independent of nitric oxide production. Clin Nutr. 27(4):649-656.  IM

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