Body Mass Index (BMI): this method is used to assess weight relative to height, it is calculated by dividing bodyweight in kilograms by height in meters squared (kg/m²) A BMI ranging between 25.0 to 29.9kg/m² is considered overweight whereas a BMI of 30 or greater is considered obese. However due to the large margin of error associated with estimating percentage body fat from BMI (+/- 5% fat) it is not considered a useful tool for evaluating an individual’s body fat.
Skinfold measurement: a skinfold thickness is two layers of skin and two layers of fat, to measure the skinfold thickness, a calipers is used, this should be calibrated and have a constant pressure of 10 g/mm². Body fat percentage determined form skinfold measurements correlates well with that determined through hydrostatic weighing (r = 0.79 – 0.90). This technique is based on the principle that the amount of subcutaneous fat is proportional to the total amount of body fat. However, age gender and ethnicity all have an effect on the proportion of subcutaneous fat to total fat, which means that these variables must be considered when using the regression equations to convert sum of skinfolds to percentage body fat. Assuming that the correct technique ahs been used and that the correct equations have been applied, the prediction of percentage body fat has an accuracy of ±3.5%