Getting a leg up in competitive running


July 27, 1993|By Gabe Mirkin, M.D. | Gabe Mirkin, M.D.,Contributing Writer

The best way for competitive runners to train to run faster is to strengthen their leg muscles by running very fast in practice, running up hills and using strength training machines.

There are two ways to run faster: You can move your legs at a faster rate, which is called cadence, or you can take longer steps. A video at the New York City Marathon showed that the top 150 runners had the same cadence, taking 92 to 94 strides a minute. The difference between the top runners and the others was that the best runners took longer strides.

Trying to lengthen your stride slows you down. Your most efficient stride length is determined by what feels most comfortable to you. Your heel hits the ground with great force. The tendons in your legs absorb some of the energy and then contract forcibly so you regain about 60 percent to 75 percent of that stored energy. When you try to take a stride

that is longer than your natural one, you lose a great deal of this stored energy and tire much earlier.

The key to running faster in races is to make your leg muscles stronger so you can contract them with greater force and they will drive you forward with a longer stride. Competitive distance runners strengthen their legs by running very fast in practice two or three times a week, doing leg presses two or three times a week and by doing hill training once or twice a week.

What does HDL cholesterol mean?

HDL is the good cholesterol in your bloodstream that helps to prevent heart attacks. HDL is helpful because it carries cholesterol from your bloodstream to your liver where it can be converted to bile and removed from your body. HDL balances blood levels of the bad LDL cholesterol. If your bad LDL cholesterol is 100, you need at least a 40 HDL cholesterol to protect you. If your LDL is 140, you need an HDL of

at least 70 to protect you. You want to have as much of the good HDL cholesterol as possible.

Having a low HDL while you are on a high-fat diet markedly increases your chances of developing a heart attack. However, if your HDL goes down when you start a low-fat diet, you do not increase your chances of developing a heart attack. When you go on a low-fat diet, your HDL cholesterol drops in a good way.

I saw an ad claiming that candy bars made with medium-chain triglycerides are not stored as fat in your body, so you can eat as many as you want. That sounds too good to be true.

You're right to be skeptical. Eating most types of saturated fat raises blood levels of cholesterol. One type of saturated fat, called medium-chain triglyceride, does not raise cholesterol. However, these fats are still rich sources of calories. Eating candy bars containing medium-chain triglycerides can make you fat because fats have 9 calories per gram, or twice as many calories as carbohydrates and proteins.

Most commercial medium-chain triglycerides are extracted from coconuts and are used to treat people who have diseases that interfere with the absorption of foods through the intestinal tract.

For many years, bakers added coconut oil and other tropical oils to their products to make them taste good.

Dr. Mirkin is a practicing physician in Silver Spring specializing in sports medicine and nutrition.

United Feature Syndicate

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