The penny's just dropped

I’m a 100kg rider with a ftp of around 215. I was watching a YouTube video of an cat A rider the other night and he was doing about the same watts as my ftp but he was banging out about 4.5 watts per kilo hence him being a cat A rider. My first reaction was I can do what he does but then the penny dropped and I realised its obviously down to him being lighter. (Forest gump moment)
I’m asking the question, is there an optimal weight to get to before it affects your power to weight ratio. I’m guessing all the cat A riders are roughly the same weight if they’re roughly the same height. Does that make sense?
I’m probably thinking out loud here but any input would be appreciated

Hi @David_Mckay4

As your weight goes down your category will move up if your FTP stay constant. Category is weight (kg) divided by FTP (watt).

See below. this assume your FTP stay 215w.


Taking it slightly differently “is there an optimum weight to get to before it affects your power” - yes. In Geraint Thomas’ last book he describes all the work he has to do to lose weight (because most pro rider aren’t riding at their natural body weight, they are at extreme diet and trainer maintained weights) and he describes the point at which it will suddenly cause him to start losing power output (the body can only lose so much mass before the main component from which to lose mass is the muscle you’ve worked to gain).

Quite a complex answer to a relatively simple question.

You automatically get an amount of raw watts with weight. Being larger, it is easier to produce power. It is not uncommon for someone to be able to put out big raw watts, with hardly any training, if they are heavy. However, endurance is more difficult for all of the standard reasons, and endurance training is likely to result in weight loss. So, as you lose weight, you will also lose power, but you will improve w/kg. This is by no means linear pattern.

Once you get down to cat A level and above, you still get significant variety. Even in the pro peloton there is a range of weights and sizes, but it becomes a more narrow range and narrower still once you look at specific phenotypes and strengths/weaknesses - long steep climbers tend to be lighter, for example. Again, there is still a range - look at Roglic, awesome climber but by no means a stick.

Losing weight will generally result in improved performance overall, until you get to a natural point where you have a good balance between power as required for your chosen discipline or specific strength. But exactly what that weight is be very personal. At pro or top level, there are very few riders over 80kg.

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No weight does not = muscle.

That is not true. With a good training program and loosing fat not muscle you can maintain power or even increase your FTP.

2019 FTP 300 Weight 112kg
2021 FTP 351 Weight 92kg


Not to bring up a competitor, but the Trainer Road podcast regularly features their CEO Nate and he has commented that when he loses too much weight his FTP drops and when he is 10 or so lbs heavier and incorporates weight training in his routine (to Gerrie’s point about maintaining muscle mass) his FTP increases. So, through a lot of N=1 testing he found his “sweet spot”. This will likely be different for everyone, so experimentation is the key.


I think you have misread what I put.

You DO get power automatically with weight.

2 completely untrained people with sedentary lifestyles. One 85kg. One 120kg. The 120kg will be able to provide more raw power initially. It’s science, I can go in to more details / papers / studies if required.

Is it possible to lose weight and maintain power or increase power? Yes of course, but that is not easy to do at all, particularly in the early phases where weight will drop quickly and that initial power starts to come down.

You said you had an ftp of 300w at 112kg. I assume that was basically untrained. Yet an ftp of 300w for a 65kg rider can only be obtained with significant training.

To be clear also, muscle != power.

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Optimal weight is really affected by a lot of factors, and while the spread definitely is lower among a cat there really is still room for quite alot of different guys even at pro level. Hugh Carthy (GC rider) and Filippo Ganna (TT specialist) are both 1.93 m, but one is 69 and the other 82 kg. You do have a point with the optimal power to weight ratio, but its extremely hard to find even for top pros, and it might shift as well.

One of the key things with cycling is that at heart its an endurance sport, and that pretty much explains why a low weight is generally favorable, because the raw wattage a guy at 100 kg can do have a ceiling that makes it pretty much impossible to reach the same potential as a 65 kg rider. That ceiling is energy consumption and replenishment, because a higher raw wattage output leads to a higher consumption of energy, so basically a lighter rider can more effectively use the available energy than the bigger guy.

One thing to remember is that weight itself can lie, because muscle weighs more than fat. So if you are looking at loosing weight using zwift or other forms of training, you might not always see the desired result on the scale, but you are still getting stronger and improving both your physical abilities and your overall health.

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Pound for pound, muscle weighs exactly the same as fat - a pound!

“Muscle weighs more than fat” is a totally inaccurate and useless statement. Muscle is more dense than fat - yes. Exercise does not simply convert fat into muscle - yes. Through training you can gain muscle without necessarily losing fat - yes.

But with training and reasonable diet, fat loss is the norm even if the rates of gain and loss for each may differ. Also through training you can affect where the muscle is - super biceps don’t contribute much to cycling FTP, so ‘pound for pound’ as bad as fat (though more dense so probably more aero).

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That was after more than a year on Zwift. The reason I didn’t quote my first numbers is because my first trainer wasn’t that accurate. :pleading_face:

Yeah its an oversimplification but the concept it still the same that training has the possibilty of converting some fat into muscle, and this may effect results on the scale compared to just dieting

Overbody wieght and muscle will not help endurance cycling but i did note that this was just training in general not cycling. For sprints or other short anarobic efforts you actually want some overbody to help store lactic acid, part of the reason track sprinters have much larger overbody compared to normal cyclist

Sure, but un untrained lightweight rider (especially one without any base fitness from other sports, assuming at 112kg that was the case?) does not usually get to a 300w FTP after a year of zwift. There is a guy I have raced often, a former pro rugby player, with a 400w FTP at 100kg. That is a world class FTP if he was sub 70kg, and still a good 4 w/kg FTP without. The reality is there is no way he could hold that raw watt FTP at a lower weight.

He may not want to of course (especially considering the advantage you get being heavier on Zwift, which is another topic) which is also fine - it’s about finding a balancing point for your body type and goals.

It’s very difficult to do both at the same time depending on how experienced you are.

You need fuel to complete the hard workouts which will improve your fitness. Losing weight requires a reduction in calories which will impact your ability to perform and recover from tough workouts.

If you are relatively new and starting from a low base you can do both. But for experienced riders, lose weight first then focus on increasing power. Base training is a good place to lose weight.

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Very true. Not to mention that muscle volume on it’s own contributes little of value to cycling if the cardiovascular system is not developed. Aside from creatine-phosphate system requirements (track sprinters) there is a reason few world tour pros have huge legs. Hugh Carthy a good case in point. Barely any muscle volume on him, but it is about muscle fiber type, mitochondrial density, efficiency, endurability, etc. Any extra weight (including muscle) has to be offset by an overall performance improvement DUE to that extra weight. That’s what the (very personal) balancing point is all about.

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So as per the chart at the top, if I inputted my weight into zwift at half of what I actually am therefore becoming a 50 kilo rider overnight this would automatically put me as a cat A rider. Is it that simple an equation?

Yes if you have the same FTP and you weigh 50kg then you will be classed as a Category A racer. It is not to say you would be able to keep up with the A racers.