How to Figure Out Lean Body Mass

If you would like to change your physical appearance, knowledge of your lean body mass is very helpful. To figure out your lean body mass, you must first know your percentage of body fat. Once you know your body-fat percentage, calculating your lean body mass involves two simple steps.

Things You'll Need

• Partner
• Paper
• Pencil
• Calipers
• Calculator

Instructions

Measurements for Body-Fat Percentage

1. Remove all clothing except your underwear, and stand up straight.

2. Begin with a chest measurement. Ask your partner to take a diagonal measurement of the pinch point with the calipers. On men, the proper pinch point is located halfway between the armpit and the nipple. On the woman, it is located one third of the way between the armpit and the nipple.

3. Raise your arm above your head, and have your partner take a vertical measurement on your midaxillary line. This pinch point is below the center of your armpit, level with your nipple.

4. Take a subprailiac measurement. The pinch should be diagonal and is located right above the place where your hipbone protrudes forward.

5. Move 1 inch to the side of your bellybutton, and pinch with the calipers in a vertical position. This is your abdominal measurement.

6. Measure a vertical pinch halfway between the top of your thigh and your knee. This is the thigh measurement.

7. Take a vertical tricep pinch at the halfway point between your elbow and the top of your shoulder. Your arm should be slightly raised from your side, and your palm should face behind you.

8. Record the measurement of a diagonal pinch located right below your shoulder blade. This is called the subscapular measurement.

9. Add up all the measurements taken in the previous steps. This total is referred to as "SUM" in the following formulas.

Calculations for Men

1. Perform the following equation: 1.112 -- (0.00043499 * SUM²) + (0.00000055 * SUM²) -- (0.00028826 * YOUR AGE). This calculation gives you your bone density.

2. Perform the following calculation to get your total body-fat percentage: [(4.95/Bone Density) -- 4.5] 100. The resulting number is your body-fat percentage.

3. Write down the results.

Calculations for Women

1. Perform the following equation: 1.097 -- (0.00046971 * SUM) + (0.00000056 * SUM²) -- (0.00012828 * YOUR AGE). This calculation reveals your bone density.

2. Perform the following calculation to get your total body-fat percentage: [(4.95/Bone Density) -- 4.5] 100.

3. Write down the results.

Lean Body Mass Formula

1. Perform the following calculation: BODY FAT PERCENTAGE * TOTAL BODY WEIGHT. This number is an estimate of how many pounds of fat you are carrying.

2. Subtract the number of pounds of fat from your total body weight to calculate your lean body mass.

3. Consult your doctor to determine whether your lean body mass is in a healthy range.

References

• Gain Weight Muscle Fast: Calculating Lean Body Mass
• Gain Weight Muscle Fast: How to Take Skinfold Measurements

Resources

• Women Fitness: Building Lean Body Mass