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I routinely see people in the gym performing calf raises with their toes pointed every which way. They’ll turn their toes inward (pigeon-style), then forward, then outward…and pretty much every direction in between. All of this effort is undertaken in the mistaken belief that changing toe position allows you to work different areas of the calf muscle. Unfortunately this is not the case. Here’s why:

In order to effectively alter the stimulation a muscle receives, you need to do one of two things: 1) increase the amount of stretch on the muscle or 2) place the fibers in a position so that they more directly oppose gravity or contract in line with fibers. Turning the feet in or out accomplishes neither of these objectives. These movements (called internal and external rotation) are achieved by rotating at the hip. The problem here is that the calves, of course, don’t cross the hip joint! They are affected only by movements that take place at the ankle and (in the case of the gastrocnemius) the knee joints. Hence, there’s no physiologic way foot position can be of benefit in enhancing calf development.

What’s more, performing weighted calf movements with the feet splayed too far in or out can place undue stress on the knee joint. The knees simply aren’t meant to track in this fashion, and doing so can heighten the potential for soft-tissue injury.

So the question really becomes: Is there any way you can exert stimulation to different parts of calf muscles? The answer: To a limited degree. The gastrocnemius muscle has two separates “heads”: the medial head (which resides on the inside of the lower leg) and the lateral head (which resides on the outside of the lower leg). By rolling your foot onto the big toe (called inversion), you place the fibers of the medial head in a position to more directly oppose gravity, thereby increasing stress to this part of the muscle. Contrarily, by rolling your foot onto the little toe (called eversion), the fibers of the lateral head more directly oppose gravity, thus increasing their force production.

Now understand that this doesn’t mean you are isolating the respective heads. Far from it. Both heads will receive significant work during the exercise. If anything, the effect will be slight, with the target head being stimulated slightly more than the other.

Moreover, the soleus muscle (which lies deep underneath the gastroc), will not be affected by inversion or eversion. You can, however, target the soleus vis-à-vis the gastroc. Since the soleus only crosses the ankle joint and not the knee, it remains highly active when performing bent knee calf raises while the gastroc, which crosses both the ankle and knee, does not. Thus, exercises such as seated calf raises will focus more on the soleus whereas straight-legged movements (i.e. standing calf raises, donkey calf raises, etc), involve both the gastroc and the soleus.

Stay Fit!

Brad

L-Carnitine has been a popular supplement in bodybuilding and weight loss circles for many years, and it has recently seen renewed interest from its inclusion in the many “energy drinks” on the market. That begs the question: are there any benefits to carnitine supplementation? To answer this question, let’s first start with a little physiology on the substance…

Carnitine is synthesized in the liver and kidneys from the essential amino acids lysine and methionine. It also can be obtained intact from whole foods such as avocados, red meat, and various dairy products. The primary function of carnitine is to transfer fatty acids across the mitochondrial membrane so they can be oxidized to produce energy. Thus, it is integrally involved in the fat burning process, as well as helping to enhance energy levels and reduce muscular fatigue.

From a hypothetical perspective, carnitine supplementation makes sense on the surface. First, because of its role in facilitating transport of fatty acids into the mitochondria (the body’s “cellular furnace”), an elevated level of carnitine would seem to permit a greater amount of fat to be burned by the body. In addition to accelerating weight loss, this would also help to spare muscle glycogen, thereby improving exercise performance. Moreover, since carnitine plays a role in buffering lactic acid, supplementing could theoretically prolong your ability to work out at intense levels. And carnitine has various cardiovascular benefits, including the reduction of blood cholesterol and lipids. All things considered, supplementation might sound like a good idea, right?

Unfortunately, theory doesn’t transfer into practice here. The vast majority of studies have shown little or no benefit of carnitine supplementation in healthy, well-nourished individuals. There appears to be a critical level for carnitine build up, above which it provides no additional effect. While supplementation does increase blood levels of carnitine, there is not a corresponding increase in transport of fats into the mitochondria, and thus fat burning capacity is not enhanced. Provided you take in sufficient dietary protein (equating to approximately one gram per pound of body weight), the overwhelming likelihood is that you will synthesize all the carnitine your body needs. And given that carnitine is quite expensive, supplementation just doesn’t provide a good cost/benefit.

The only instance where supplementation may be beneficial is if, by chance, you happen to have a carnitine deficiency. Those most at risk for being deficient include vegans, vegetarians, breast-feeding women, and individuals on very low calorie diets. Should you fall into one of these categories, it’s possible that carnitine can be of value. Standard dosage is to take between two and four grams of carnitine approximately one hour before exercise. Again, more is not better—once you reach the saturation point, any additional intake will be superfluous. And assuming you are not deficient (as is the case with the vast majority of the public), save your money.

Stay Fit!

Brad

I generally don’t get political in this blog–after all, my focus is on the science of fitness, not the world of politics. However, a recent issue here in New York has motivated me to take up a cause. Namely, New York governor David Patterson has proposed a tax on soda and other sugary beverages. The tax would encompass soft drinks, energy drinks, sports beverages, and various juices and iced teas; sugar-free diet soft drinks would not be affected. It is estimated that such a tax would bring in about $1 billion over the course of a fiscal year, enough to make a significant dent in New York State’s $8.2 billion budget deficit. My only question: what took so long?

Predictably, beverage makers are up in arms over the bill. The American Beverage Association is lobbying hard to rally opposition against it. They have created an organization called American’s Against Food Taxes and set up the No Beverage Tax website where readers are encouraged to sign a petition against the governor’s proposal. They profess that tax against soda is discriminatory. They imply it is Un-American, harmful to the poor consumer who is overburdened by the recession. Before any tears well up, let’s get real here. We’re talking about making people pay a few cents more for something they shouldn’t be drinking in the first place. Here’s a simple solution for those who feel this causes financial hardship: switch to tap water–it’s free and has no calories!

Make no mistake, sweetened beverages, particularly sodas, are a major threat to public health. These beverages have no nutrient density whatsoever. Zilch! They epitomize the term “empty calories.” Worse, they are digested very quickly into your blood stream, and therefore don’t satisfy hunger—a fact that can lead to overeating. What’s more, they elicit a rapid spike in blood sugar levels, which in itself can lead to excess fat storage as well as increasing sugar cravings. And on top of everything, they’re bad for your teeth, too!

In a recent review of research appearing in the New England Journal of Medicine, Brownell and Frieden (1) reported that consumption of sugary beverages is associated with increases in body weight, poor dietary habits, and an elevated risk of obesity and diabetes. Conversely, a reduced consumption of these beverages has a positive effect on health and wellness. But that’s not the worst of it…

Soft drinks companies focus a great deal of their marketing efforts on children and adolescents, so much so that sugared beverages now comprise 10 to 15% of the calories they consume. It is estimated that each additional glass a child drinks increases his/her likelihood of becoming obese by approximately 60%. Given the epidemic of childhood obesity and its ramifications (approximately one-third of all children in New York State are classified as overweight or obese), this is something that needs to be addressed. Soon!

The real question, then, is whether a soda tax would have any impact on consumption? Evidence suggests it would. Research published in the American Journal of Public Health shows that taxes on cigarettes have substantially curbed the rate of smoking in America (2). What’s more, larger tax increases were associated with larger smoking declines, with the greatest effect seen in youth, minorities, and low-income smokers. This bodes well for the effectiveness of a tax on sugary beverages.

In their article, Brownell and Frieden estimate that for every 10% increase in price, soda consumption decreases by 7.8%. They quote an industry trade publication report that shows even greater price sensitivity: a 12% increase in the price of Coca-Cola resulted in a 14.6% drop in sales. These statistics provide powerful support to the belief that a soda tax would decrease consumption of sugary beverages. If so, this would reduce caloric intake, leading to better weight management for millions of Americans.

An essential aspect of any soda tax is that revenues must go toward offsetting health care costs (the money collected from the proposed tax in New York would be targeted for an existing pool that funds the state’s health expenses). The medical expenses associated with overweight and obesity are staggering. Taxpayers assume the majority of these costs through Medicare and Medicaid. This clearly is unjust. Why should those who watch their diet and maintain their health pay for those who don’t? If a person wishes to consume sugary beverages, that is certainly his right. But he then should be responsible for bearing the costs associated with his decision, not the taxpayers.

Bottom line is that a tax on sodas and other sugary beverages is an idea whose time has come. It will help to make us healthier as a nation, and transfer some of the economic burden of skyrocketing medical costs to those who don’t assume responsibility for their own health. Perhaps the success of such a tax in New York will motivate congress to pass a national tax on sodas and sweetened beverages. And perhaps then, despite the protests from special interest groups, we’ll have a healthier nation because of it.

Stay Fit!

Brad

1) Brownell KD, Frieden TR. Ounces of prevention–the public policy case for taxes on sugared beverages. N Engl J Med. 2009 Apr 30;360(18):1805-8.
2) Peterson DE, Zeger SL, Remington PL, Anderson HA. The effect of state cigarette tax increases on cigarette sales, 1955 to 1988. Am J Public Health. 1992 Jan;82(1):94-6.