Secrets of Racing Weight For Triathletes

Essential Tips on Race Weight and Body Fat for Triathlon Preparation…

Body Fat Percentage For Triathlon

It doesn’t take a rocket scientist to work out that the world’s best triathletes are pretty low in body fat. The recommended body fat levels for high performance in men are 5-10% and 10-15% for women.

The biggest performance benefit of a low body fat percentage is that it makes you lighter. In other words, you’ll expend less energy hauling your ass around a triathlon. Two of the biggest measures of performance in triathlon are 1) power to weight ratio and 2) running economy.

TOP TIP: Your body weight forms a big part of both of those calculations.

You can follow a well-designed triathlon training plan or specific cycling training plan to boost your output as much as you like (like our FTP booster plans), but holding on to a few extra kilos/pounds of body fat will still limit your results – and probably by more than you think!

Triathlon Cycling Training and Race Weight

Below you can see a chart compiled by legendary cycling scientist Andrew Coggan, which shows a population of cyclists from beginner to pro and their cycling power to weight ratios. It gives you an idea of how changes in your weight or power output affect your cycling ability. This also highlights why professional cyclists need to be so skinny.

For example, if your ‘FT’ (your maximal 1-hour power) is 250 watts and you weigh 70kg, your FT power to weight ratio would be 3.57 w/kg. Let’s play around with this and say you lost 2kg and you now weigh 68kg. That means your power to weight ratio goes up to 3.67w/kg. This would lift you 3 places in the table below, without you having to improve your cycle power output. Not bad eh?

Power to weight ratio triathlon

Triathlon Running Training and Racing Weight

Now you’ve seen what a difference weight makes to cycling, you should also check out this link to a running weight loss calculator. It gives you an idea of how changes in weight might affect your running ability. You can enter your best recent times for various distances (for example 5km or 10km) and it’ll show your predicted times at various body weights. It’s a real eye-opener.

Running Weight Effect Calculator

Triathlon Performance Benefits at Race Weight

While we’re at it, there are a couple of other performance benefits of low body fat for triathlon too:

  1. Thermal regulation – with low body fat you won’t waste so much energy trying to stay cool during a triathlon.
  2. Aerodynamics – the smaller you are, the less drag you create. Losing a millimetre of fat all over your body is like upgrading to an aero-helmet.

So it’s safe to say that you’ll perform better at triathlon if your body fat is between 5-10% for men and 10-15% for women. Easier said than done.

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How to Lose Weight But Not Muscle

The trick is to lose fat and maintain muscle. Research suggests that you can achieve this by reducing your carbohydrate intake slightly while maintaining your protein intake. One way to do this is to cut out alcohol and sugary foods. The other trick is to lose weight slowly, with a daily deficit of no more than 500 calories. At this rate, it would take you a week to lose one pound (or half a kilo) but you should still maintain your existing muscle.

Hitting your race weight is something we recommend you do for your big races, but not necessarily all year round.

Phil Mosley (Coach & Founder)
Phil Mosley (Coach & Founder)

Phil is a recognised endurance expert who founded MyProCoach in 2010 to offer smart training plans that still leave quality time for your family, friends & career - complete with highly-rated coach support (he has sold over 40,000 so far). Learn more here!

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