Friday, April 28th, 2006

In a previous column, I talked about measuring heart rate or using the rate of perceived exertion with regard to cardiovascular or aerobic activity. In this column, I would like to talk about a better way than the scale to determine and measure progress in your fitness program.

The most used pieces of equipment at SFF are the scales. Everyone wants to weigh themselves to see if they have lost or, in some cases, gained weight. While there are many people who are considered overweight, there are still more whose main problem is not so much body weight as excess body fat. Body fat measurement is a much better way to measure fitness and progress in a fitness program.

There are several ways to measure body fat including hydrostatic measurement which needs to be done in a special pool and can be quite expensive. Bioimpedance is another way and there are a number of scales on the market that send a pulse of electricity through the body to determine body fat. In my experience, for some people these can be very inaccurate. The same DEXA scan used in hospitals for bone density measurements is another accurate but costly method.

The most common way to measure Body Fat is to use special calipers to take measurements of skin folds in precise places on the body and then to use one of a number of complex formulas to determine body fat. In the recent body fat clinic we held at SFF, I used the Durnin formula which is accurate for most people except those with very low body fat.

Why is body fat more important to establish a goal than simple weight measurement? What you should aim for is a reduction in body fat and an increase in muscle. Body fat is inactive tissue and usually biologically inactive except in the mid section where it can actually cause disease. Muscle tissue, on the other hand is active. A pound of muscle burns 30-50 calories day. Most people's muscle mass declines with age and after about age 45 the rate of decline increases.

The amount of muscle you have and retain is determined by how much you use your muscles. One of the biggest mistakes people make in the gym is to do nothing but cardiovascular or cardio exercise or to do a long period of cardio followed by doing a few "strength" exercises. Your body has used a good deal of its energy reserves doing the cardio and so has little energy to properly complete a strength workout. You should warm up for strength training by doing 5-10 minutes of moderate cardio activity such that your heart rate should be just below the aerobic zone at about 50-60% of your maximum (220-your age). If you have excess body fat, it is good to do cardio most days of the week.
However, if you are strength training on the same day, do 5-10 minutes of cardio followed by strength training and then complete your cardio regime.

Now, why is the scale is not the best measurement of progress? Simply put, muscle weighs more than fat. Muscle is about 20% more dense than fat. You can weigh 180 pounds before embarking on a fitness program and still weight 180 pounds two months later. Does that mean you have not made any progress? Not at all. Your body COMPOSITION may have changed significantly and you probably have lost fat but gained muscle. How the will you know if you're making progress. Have your body fat measured.

Below you will find tables for men and women of what your percentage of body fat means. If you would like to have your body fat measured as well as other measurements taken which I will talk about in future Trainer's Edge columns you can call or email me.