Thursday, March 15, 2007

A pinch for good measure- checking your progress

Let's say you've been working out for a few weeks and you're not quite sure about your progress. What's the best way to measure your success? Well, here's the skinny on a few different techniques.

Skin Fold Caliper Measurements
While this may not be the most accurate technique in assessing the exact percentage, it is an accurate way to chart progress. Caliper measurements are done by measuring the amount of fat that can be pinched from three to seven sites on the body. Most fitness professionals use the Durnin/Womersley formula, which is a four site upper body measurement. The key to an accurate measurement is consistency.

Bioelectrical Impedance
This technique uses a portable instrument (or a scale) to conduct an electrical current through the body. This is based on the hypothesis that tissues that are high in water content conduct electrical currents with less resistance than those with little water (like body fat). This is not the most accurate technique due to the constant fluctuations in hydration.

Underwater Weighing
This technique is the most accurate in determining the exact percentage. This method determines the proportion of fat to lean body mass. This is done by weighing a person through normal methods and then, being weighed again underwater. Because lean tissue is denser than fat, the more lean a person is, the more they will weigh underwater. The results indicate a person's overall density. While this may be the most accurate technique, it's not the most practical. Unless you have access to an exercise physiology lab.

Circumference Measurements
This is another technique that can be very beneficial with consistency. Not only is this a useful technique to asses gains in lean body mass, but also the percentage of body fat. This is an excellent alternative for when skin fold measurements are not an option. The measurement sites are: neck, chest, upper arm, forearm, waist, thigh, calf.

Waist-to-hip Ratio
This is one of the most used clinical applications of girth measurements. This can be an important assessment because there is a correlation between chronic diseases and fat stored in the midsection. The ratio can be determined by dividing the waist measurement by the hip measurement. If your waist measures 30 inches and your hips 40 inches, the waist-to-hip ratio is 0.75. A ratio above 0.80 for women and above 0.95 for men may put people at risk for a number of diseases.

Body Mass Index
This technique is not designed to assess body fat, but the BMI is an easy method for determining if your weight is appropriate for your height. To calculate this measurement, divide body weight (in kilograms) by height (in meters squared). The obesity classification using BMI are : mild = 25-30, moderate =30-35, Severe >35. This assessment is not accurate for athletes, due to lower body fat percentages and higher amounts of lean body mass.

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