Question

***In order to receive credit for questions 3-4, round to the nearest hundredth 3. A high school cross country runner has a BOD POD measurement to determine his body fat percentage. Currently, his body fat is 14% and his weight is 162 pounds. His goal percentage is 10% body fat. Please calculate his fat mass. (1 pt. Please calculate his fat-free mass. (1pt.) What weight corresponds to 10% body fat? (3 pts.) 4. An elite female gymnast undergoes a hydrostatic weighing test to determine her body fat percentage. Her current body fat is 15% and her weight is 120 pounds. Her goal for body fat percentage is 12%. Please calculate her fat mass. (1pt.) Please calculate her fat-free mass. (1 pt.) How much weight would she need to lose in order to get to her body fat percentage goal? (3 pts.)

Answer 1

3. Body weight = 162 pounds

Fat percentage is 14%

Fat mass is 14% of 162 pounds which is = ( body weight * fat percentage)/100

which is (14*162)/100 = 22.68. The fat mass is 22.68 pounds

Fat-free mass = total mass - fat mass

which is 162-22.68 = 139.32. Fat-free mass is 139.32 pounds

Assuming the weight lost is only due to fat loss. For fat percentage to be 10% the fat-free mass should form 90% of whole weight.

As fat-free mass is 139.32pounds, the total body mass at 10% fat is = (fat-free mass*100)/90

which is (139.32*100)/90 = 154.8 pounds.

154.8 pounds corresponds to 10% body fat.

4. Current body weight = 120 pounds.

Body fat percentage = 15%

Fat mass is 15% of 120 pounds which is = ( bodyweight * fat percentage)/100

which is (120*15)/100 = 18 pounds. Fat mass = 18 pounds.

Fat-free mass = total mass - fat mass

which is 120-18 = 102 pounds. Fat-free mass = 102 pounds.

Assuming she only looses fat and not fat-free mass. For her fat percentage to be 12 % the fat-free mass should form 88% of the total body mass.

As fat-free mass of 102 pounds is 88% of total mass,

total body mass to be achieved to have 12% fat is = (fat-free mass * 100)/88

which is (102*100)/88 = 115.91 approximately.

The difference is 120-115.91 = 4.09

She needs to loose 4.09 pounds to get fat percentage to 12%.

This is a brief discussion. I have used the words weight and mass interchangeably, hope you don’t mind. Hope this helps you out. Please feel free to give a like and contact us if you need further detailed explanation. Thank you and have a great day.