Video 5 - Height, weight and body mass index (BMI)
‘All information contained in these videos is taken from the ACSM’s Guidelines for Exercise Testing and Prescription, 10th Edition’
Body weight should be measured using a calibrated balance beam or electronic scales, with the client wearing minimal clothing, no shoes and having empty pockets. Once the scales have been ‘zeroed’ the client should step on and remain stationary until a reading is taken.
For height, or stature, measurement, shoes should be removed prior to stepping on to the stadiometer. Clients should stand upright with heels together, buttocks, upper back and head in contact with the stadiometer, with head level and looking straight ahead. Measurements should be recorded to the nearest 0.1cm.
Once weight and height have been measured, Body Mass Index can be calculated by dividing body weight in kilograms by height in meters squared. As outlined in table 4.1 (p 70), a BMI of less than 18.5 is classed as underweight, between 18.5 and 24.9 as normal, 25-29.9 as overweight, and over 30 as obese.
It must be remembered that BMI fails to take into account the amount of muscle mass an individual has, therefore those who are quite muscular will often be classified as overweight when in fact they are not. For this reason, other assessments of body composition that more accurately measure body fat may be considered, or the use of circumferences such as waist and hip alongside BMI.