BMI figures

What source should I be using to determine where my clients are 

situated in terms of their BMI?

I have 3 or 4 different text books + publications all saying slightly different things. And in 

some cases very different things. 

Should I just use the NZ MOH guidelines? I have noticed in some stats

they give they don't differentiate between male and female, just age group.

SAm

Hey Sam,

In my experience as a Personal Trainer I haven't used the BMI scale; I was more inclined to use more specific data. For example I would take blood pressure to check general state of health, I would do girth measurements (at least 4 sites), and if the client wanted them I would do skin folds (but worked on the sum of seven rather than percentages).

This is something that as trainers we need to be educating out clients on, finding out what THEY want, then this is down to the trainer to select the most valid and reliable test.

I think there is a place for the BMI index but it would need to be used alongside other relevant data as well.

B.M.I. does provide some information but it has big limitations. It doesn't differentiate between visceral (belly fat) fat and the regular subcutaneous fat that is acceptable.  It doesn't take into account ethnic differences - a big consideration in N.Z. as some cultures while (generalising here) carrying excess fat also carry a high muscle percentage.

Other factors are more important in my opinion, how the person feels about their size is an indicator even, waist to height measurement, blood pressure, B.M.R - of course you have to get an understand of this one to use it.  Muscle and fat %'s are useful as we know what the accepted norms are.  These can be obtained by pinch test or better still, if one has access to a Body Composition Analyser. (Just be a bit sus of the ones that are regular bathroom scales, I'm talking about real medical B.C.A. machine).

Hi Di,

Interesting how you have identified that BMI has it's limitations as it doesn't take into account a number of variables you have mentioned above but you feel the figures (percentages) based on 'norms' used for body fat percentages are relevant? What I think is important from being a PT is not loosing yourself in the technical mumbo jumbo that is out there and keeping it relevant to the client. If it is as simple and getting the old fashioned tape measure out and doing the manual labour of taking some girths then to me this is far more reliable than a machine that will tell me I have X amount of body fat.....

 

 

You've got it, Sarah. Clients know if they are feeling better, stronger, can do more. The know if they are getting results and it doesn't take any machine to tell them that (talking about regular people here, not athletes).  Losing or gaining weight or fat, gaining muscle shows with the mirror and the tape measure and how a person feels.  B.C.A. machines just give a printout - proof of results over a time period, say 3-6 months. They also can be useful to show nutrition status and other factors and are used mostly by hospitals.  They can also show up - Thin outside/Fat inside - the people who look thin but carry a high amount of visceral fat. A useful tool but just another tool, that's all.