Are body composition scales useful for athletes?

Traditional bathroom scales are great for showing us how much we weigh but is it worth investing in body composition scales to get a more in depth look at our body? James Pryke, coach and co-founder of Triathlon Coaching UK discusses how they work and what they offer triathletes

With running and cycling in particular, a person’s power to weight ratio is high priority if they want to improve their performance.

Every year we work with athletes who are keen to lose weight for many reasons. There’s nothing wrong with this but the danger is that many people end up going down the wrong track and losing weight rapidly rather than steadily over a period of weeks.

When someone loses weight quickly, say around 3-4kg per week, it usually means they’re losing muscle tissue and water. Muscle tissue is essentially protein and for every 1g of protein lost we lose around 4g of water so it’s easy to see why the weight can drop so easily.

Losing weight from fat mass is a slower process and is the ideal way to lose weight without any detrimental effects on the body. It also ensures that our vital glycogen stores are not depleted and, over time, we train our bodies to become much more efficient at burning fat for fuel whilst training and racing.

But how, apart from how quickly or slowly the weight comes off, do you know whether it’s lean muscle or fat you’re losing? That’s where body composition scales or a body stat assessment can help.

What's the perfect body composition for triathletes?


Body composition scales work by determining the body’s bioelectrical impedance or opposition to the flow of an electric current through the body’s tissues. Stand on a pair of body composition scales and a small electric current will pass through you taking the shortest route it can. The results will provide an estimation of the total body water which is then used to estimate both fat-free body mass and body fat.

It’s obviously very useful for both triathletes and their coaches to have this information to hand and to monitor the results over a period of time. It’s also worth noting that, if you are using body composition scales, you should follow the same parameters every time to ensure as accurate a reading as possible. This means before you even step on the scales you are optimally hydrated, you haven’t exercised in the last five hours and you’ve not eaten within the last four hours.

At the end of the day, there is no substitute for good nutrition. Giving your body the right combination of carbohydrates, fats and protein it needs to fuel (and recover) itself to an optimum level are key to improving your training, racing and losing weight. Body composition scales will certainly help to inform this process and offer a valuable insight into your own body and support your goal of reducing your overall bodyweight healthily and effectively.

You can browse a selection of body composition scales on

James Pryke is a coach and co-founder of Triathlon Coaching UK


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