Boditrax accuracy

simitch
simitch Posts: 2 Member
in Fitness and Exercise
Boditrax is frustratingly inaccurate. This week, despite working out about 5 times and eating ok (which is a normal for me), according to Boditrax I managed to lose 2kg of muscle and gain over 2kg of fat. I measure myself at the same time and with the same routine each week. Unless I'm a human yo yo, it seems one can look at boditrax machine as a gimmick and bit of fun rather than a serious piece of kit to aid Heath and fitness.

Replies

  • ledgey91
    ledgey91 Posts: 17 Member
    As far as I know they use a similar system to your generic ("advanced") bathroom scales which shoot a bit of electricity through you to measure the muscle/fat content. They're not spot on but they're alright at detecting trends - if you're gaining muscle and losing fat it will show over time. Treat it as a guide, do it often and just use the lowest/average reading as a basis. Ignore any major fluctuations etc etc.

    If you want a more 'serious' way to measure body fat, best way is calipers and a tape measure or you can pay money to get a professional assessment (but it's not usually cheap!)
  • CafeRacer808
    CafeRacer808 Posts: 2,396 Member
    Boditrax, like all "smart" bathroom scales and handheld body fat measuring devices, uses bioelectrical impedance to determine BF%. This is widely known to be both an inaccurate and imprecise way of measuring BF. I wouldn't put any stock in the Boditrax readings you're getting.

    Body calipers, in the hands of someone who knows how to use the properly, will give you a more accurate reading. For an even more accurate BF measurement, you'll need to do either a DXA scan or get yourself hydrostatically weighed.
  • suzesvelte
    suzesvelte Posts: 134 Member
    edited March 2017
    I like boditrax for a long term trends and it motivates me - it is easy, it is there at the gym and using their scales once a week is stopping me jumping on and off daily at home -- but week on week it can fluctuate a bit wildly. The main thing that throws out the readings is your fluid balance. If I get a spike in on of the readings it is always related to a spike in my water %age.

    They tell you this in their own literature. However much you "do the same" you don't have control over your digestive system. I suggest that you look at your water %ages and see how they vary at the same time as your fat/muscle ratios.
  • Bruceybruce88
    Bruceybruce88 Posts: 1 Member
    3 weeks ago I was 21% and now I’ve gone up to 26.7% .. I have also lost 2lbs.. I really don’t know how this cane be true!? I have stayed very active and my eating has not really changed.. maybe one day of eating chocolate but that surely can’t put on 5% body fat? It has really disheartened me tbh... I worked hard to get to 21% and I’m honestly really Hoping it is inaccurate lol..
    I am about to come in my period so am wondering if that can effect things? I am going to do another reading in the next week and see what it is saying....
  • NorthCascades
    NorthCascades Posts: 10,968 Member
    These things are for entertainment purposes only.
  • martinparkinson6362
    martinparkinson6362 Posts: 1 Member
    Hi @simitch,

    One thing I know that throws it is water, depending on how hydrated you are prior, during and after workouts make a huge change.

    They’re not the best for accuracy, a guide really, as the other replies have mentioned.

    Water is a great conductor, when it’s putting electrical pulses through your body to measure you, what your hydration levels at time of measure Ming can make a difference.
  • sijomial
    sijomial Posts: 19,809 Member
    My gym has a free to use Boditrax unit.

    If used under consistent conditions to get a long term trend they are fine but you need to expect and discount a few weird and wonderful inconsistent readings / data points along the way. If you are training five days a week unless those sessions are consistent and your food intake is extraordinarilly consistent you are always going to get hydration related odd readings.
    If minimising those spikes is really important to you then you would have to use them same time of day, not after exercise either that day or day before, be scrupulous about consistent hydration levels, not after eating....
    Is that level of effort worth it to you compared to just regarding it as a slightly erratic way to get a long term trend?

    Just like your bathroom scales zooming up the morning after a Chinese meal doesn't make them useless for purpose, even commercial grade BIA devices have limitations. What people shouldn't expect is to get a perfect smooth trend line or just rock up once in a while and expect accuracy.
  • sijomial
    sijomial Posts: 19,809 Member
    Bruceybruce88 wrote: »
    3 weeks ago I was 21% and now I’ve gone up to 26.7% .. I have also lost 2lbs.. I really don’t know how this cane be true!? I have stayed very active and my eating has not really changed.. maybe one day of eating chocolate but that surely can’t put on 5% body fat? It has really disheartened me tbh... I worked hard to get to 21% and I’m honestly really Hoping it is inaccurate lol..
    I am about to come in my period so am wondering if that can effect things? I am going to do another reading in the next week and see what it is saying....

    @Bruceybruce88

    It's obvious those results can't be true so you know you need to discount that piece of data rather than let it dishearten you. You know eating some chocolate one day can't derail your progress!

    If you retain water / get bloating at this time of your month then that change will affect your electrical resistance and throw out the results. If your weight changes in line with your monthly cycle you also know that's not fat related.

    Data is good but you need to think about what that data really means and assess how it's been gathered and its resulting quality. Data needs to be processed by your logical mind and not the emotional part of our brains.

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