Physiological Changes to FTP Increase

We all know about workouts to increase FTP, the duration to increase FTP, etc. But what I’m curious about is the actual, fundamental, physiological changes which correlate to an increase in FTP. For example, muscle density, increase in muscle fibers, density of blood vessels, increase in mitochondria, etc. Does leg strength and muscle size have any correlation to the potential for FTP increase? (Not w/kg but raw 60 minute ftp) Is it about muscle size and growth as much as it’s about blood vessel density or is there something else I’m missing?

Is it more possible for a muscular individual who weighs 205lbs to reach an ftp of 375 watts than a muscular person who weighs 170lbs to reach an ftp of 375 watts with both being able to reach 4 w/kg (for the 150lb person this would be about 310 watts) with the same amount or similar training.

Background and the root of my question below

I’m 205lbs, 6ft 2in, and about to turn 38. With 9-12hrs of training every week and eating like it’s my job I have been unable to drop my morning weight under 204-205lbs. I’ve consulted a nutritionist and gotten a dexa scan and according to the scan, I’m 12% body fat. My FTP during the base season (right now) is 293 and my 5 second sprint is ~1700watts. My current FTP equates to 3.12 w/kg which is unimpressive even though the number may be high to many people. Last year I had my ftp increase up to 310 during season which was 3.3 w/kg.

My long term goal is 375watts (about 4w/kg at my weight)… which to some people seems insane but for me it would be just keeping up with the local group ride. I’m tired of getting my doors blown off by guys who are the size of a toothpick, ride size 54cm bikes, and have zero explosive sprint power and I’m tired of being that guy trying to hold on at the back of the group when we go up a moderate hill.


Yes, it more possible for a heavier rider to achieve raw power, although they may be worse off in terms of w/kg, it may or may not be easier for lighter rider to achieve a w/kg target.

As you said, guys that are skinny as toothpicks making more power do not have near the muscle mass you do, which answers the question. You do not need a ton of muscle to have a high ftp.

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As you said, guys that are skinny as toothpicks making more power do not have near the muscle mass you do, which answers the question. You do not need a ton of muscle to have a high ftp.

Does this answer the question though? I don’t believe it does. Just because my sample size relates to skinny as toothpick guys doesn’t mean that’s the same for all cases. Is FTP purely a function of mitochondrial electron transport or does it also rely on muscle density/size? We know it does, but to what extent?

The larger professionals also tend to have the largest FTP well north of 400 watts. For example, when Bradley Wiggins was trying out for the Olympics he actually had to gain weight to 185lbs to put out over a 430w ftp and according to some reports his final ftp was north of 450w. There’s several other examples of people I’ve come across in the 80-90kg (176-198lb) mark that are putting out well over that 400-450w range.

In my example, assuming my weight stays at 205lbs, that would give me 4.3-4.8 w/kg at 400-450w.

So then… going back to my original question/thought: Why? Muscle size? Blood vessel growth? Something chemically that’s changing. What are the physiological changes which need to be made to increase our functional threshold power? The answer to this question should help find any flaws in our training so we could further improve to our potential. :thinking:

More mitochondria, more capillaries to deliver oxygen, more enzymes, and high cardiac output.


He was probably in a build cycle and eating like a horse. The weight gain didn’t increase his FTP. The weight was an artifact of the training needed to build that FTP.

Rather than compete against the skinny guys on their turf, you should try and blow their doors off at the local crit with your sprint.


Wiggins needed to bulk up to increase anaerobic capacity and strength for a fast standing start , an important determinant in the team pursuit which was a 4 minute event.

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Give some more respect to the “toothpick” guys who are crushing you lol.

I’m at the same weight and height as you currently, although I’m maybe at 16-18% body fat and I’m heading down to 185 before summer, currently at 205 as well at 6’2" (35 years old)

I’ve been biking for a few months, never biked before in any way seriously and no endurance sport background.

Started at 190 ftp in December and now up to 270 ftp. Training 4-5h per week on a 1000 calorie per day deficit since I started.

Got addicted to biking and have really neglected weightlifting in the last three months, I’m about to start incorporating it back into my routine.

paging @BigRed for eye watering ftp numbers. :smiley:

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The toothpick guys are probably dropping you for a wide variety of reasons: lighter, ride more, high ftp, better cardiac output to push more blood and more oxygen to the muscles. Bigger guys, outside of crits, don’t tend to find an overabundance of success outside of track and crits. Heck, look at Brennan Wertz…dude can do 500w for 20min. I think he actually did an all out effort for an hour not to long ago and did 460+…and he’s still getting dropped by the “toothpicks”.

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yeah, except for flat TT and flat crits and track, ultimately it comes down to power-to-weight ratio so FTP and weight. This started out with @J.Muzyka stating he is 6’ 2" / 188cm, mapping that to a pro/elite if power-to-weight is important you are looking at say 170lbs / 77kg tops. Big ftp, not much upper body muscle mass.

Hey @J.Muzyka :slight_smile:

Definitely hard to pinpoint the actual, fundamental, physiological changes that correlate to an increase in FTP since everybody is different and we all progress at different rates, have different abilities, genes, etc…

One thing is for sure; the best way to increase your FTP is by strengthening your aerobic energy system. Since FTP is a measurement of your aerobic fitness, training that improves your aerobic capacity and muscular endurance will likewise increase FTP. Essentially, to raise your FTP, you need to grow your aerobic base fitness, then build upon it with more specific training.

However, I think it sounds like your end goal is just to keep up with the local group rides and not get blown off by smaller riders :slight_smile: Sooo, I think your best bet is to focus on structured training and the following:

  • Training Plan: I see you just started a TR plan! That’s great! It’s important to follow the plan as best you can with consistency and quality as the combined set of workouts are meant to strengthen the energy systems that directly target the ability to sustain a high power output.

  • Training Volume: consider starting with a Mid Volume training plan, as opposed to a High Volume, and add extra TSS as you see fit watching out for fatigue levels. More often than not, too much riding and not enough rest can affect our ability to train consistently and effectively on the long run, and generate fatigue that consequently leaves us behind on group rides. Rather than thinking about how much time do I have available to train, it is better to think about how much training can I efficiently recover from.

  • FTP: while FTP is an important aspect of being a faster cyclist, a high FTP does not mean you’ll be the fastest on the ride. I bet the smaller riders you are talking about have a lower FTP than you, but simply just have the ability to sustain a high power output. Effective structured training incorporates a mix of these workouts for just this purpose. The more of your aerobic capacity your FTP can sustainably harness, the faster you’ll be able to ride.

There’s a few good blog post about this subject if interested!:


From what I’ve read, muscle strength/mass is seldom the limiter for threshold (aerobic) power. It’s much more common that the “central” aerobic system is the bottleneck and what’s going on at the extremities (leg muscles) is important, but just not typically a limiter. Larger people typically have larger leg muscles, but also have larger lungs, more blood/plasma volume, etc., so it’s not just the bigger muscles that are different. All that said, just because the core aerobic system is “typically” the limiter, that doesn’t mean it’s the limiter for everyone. And it’s all one system that works together, so I’m sure it makes a little difference having big muscular legs even if it’s trivial. And we’re all different and I assume there are some people where adding more muscle mass to their legs might significantly increase aerobic power. But most of the time, added muscle mass is gong to primarily benefit the anerobic side.

It’s very likely the OP is carrying much more muscle mass than they need to generate aerobic power, but that muscle is obviously beneficial in a sprint and other anerobic situations. Probably not a great physiology for anything going up hill for extended periods, but there is lots of bike racing that doesn’t require that ability.

It’s gonna be tough to stay with lighter guys when the road goes up, it’s just a fact. Outside of rare cases you just don’t see guys your size climbing as well as the best.

But on the flats it is watts/CdA not watts/kg so if you haven’t looked at drag that is a place to start. 3.2w/kg at 200# is always faster than 3.2w/kg at 150# on the flats and false flats.

I’m curious about your question too….like exactly why can one person do 400 watts and another 200 watts? Although these days it’s more “why exactly can’t I do as much now as 3 decades ago?” lol.



This makes me think of EJ, he lost ~80 pounds, had a lot more body fat than you but put himself into a caloric deficit through diet and a ton of Z2. Generally when people are losing weight they aren’t purely losing fat, they lose some muscle even when they try not to.
I expect there will be some that dislike the suggestion of weight loss.
I’m in the opposite situation started out at 56kg now ~59kg, have been hovering around 4w/kg for a while but where my weight is so low its almost meaningless. The fastest guys in my region are 6-11kg heavier than me with FTPs ~4.6-4.7w/kg. However, that means their sweet spot is my FTP, so they can easily roll me off their wheel without even throwing an attack.
Even if I get up to 60kg and add an additional 0.2 w/kg, its still only an FTP of 252 (I would be stoked to get there but I don’t think it would solve all my problems).

I’ve heard in the past that in the world tour, while there are some outliers, there is a general phenotype 5’9-5’11 with a weight of 65-75kg, I can’t remember the source for this but I expect some of those match stick people you complain about are likely closer to that ‘ideal’. If its any consolation I have been beat by big heavy brutes before in races, in my area its lots of rolling terrain, short climbs 1-5 mins, 5-7%. Got beat on a climb finish by a guy that probably has 70 pounds on me and when I looked at his power data he avg’d 555 watts over the climb. A year and a half of training later and I still don’t think I could keep up, let alone beat that.
A workout like Woolwell Log In to TrainerRoad would still only have me doing my VO2Max efforts at 250 watts.
All this to say, the further you are from that ‘ideal’ the more challenging it is to be really fast it seems.


Blockquote I’m curious about your question too….like exactly why can one person do 400 watts and another 200 watts? Although these days it’s more “why exactly can’t I do as much now as 3 decades ago?” lol.

Honestly, that’s the reason I was asking this question. I wasn’t asking this question to poke at my personal size or anything, but rather to figure out what the root cause to higher FTP is so we know what physiological changes need to be made. I’m 205lbs. I need my ftp to be ~400 (for example). So what changes would have to occur in my body, as an example, to cause my FTP to be raised by 100 watts. The same could be said for absolutely anybody. My wife has an FTP of 177 watts and obviously weighs far less than me.

Furthermore, why is it that many lightweight riders simply cannot put out the power I put out. Period. It has to be related to physical strength at least on one level, but on another level there’s additional factors occurring.

I wasn’t posing this question to talk specifically about myself. I already know how to outsprint people and get myself on podiums during certain races. I’m asking about the scientific root cause here so hopefully everybody benefits from the answer.

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Kolie Moore went into a lot of depth on this on his podcast here:

Basically (and I’m recalling this imperfectly), not all physiology scales the same way, and at a certain point the extra muscle mass becomes more of a hindrance than a help.

Large muscles cool less effectively because there’s less surface area relative to muscle size, they’re heavier and require more work to spin efficiently, things like that. Plus the central adaptations (I.e. heart, lungs) don’t scale up in proportion in the same way. Doubling muscle mass doesn’t in any way guarantee a doubling of cardiovascular capacity. There are numerous potential bottlenecks in the system that don’t have anything to do with muscle mass.

As someone who’s similarly 6’1" and about 205 with roughly the same FTP, the podcast definitely resonated with me. That said, I’m finding increasing volume to be tremendously helpful.

Moving from 5-7 hours/week last spring to 10-12ish through the summer brought me past a long-standing 300W FTP brick wall I couldn’t get past for 3+ years and hit 319 last July. I’ve been keeping fairly consistent at 10-12 hours since early December, so I’m really eager to see what happens at my first gravel event next month. I’m also working on weight and am hoping to get below 200 before my event.


High VO2 Max is your entry ticket for high FTP. Your fractional utilisation will top out at an absolute maximum of about 90% of VO2 Max, and so someone with an off-the-couch VO2 Max of 60 is genetically better placed to achieve a high FTP than someone with an off-the-couch VO2 Max of 40.

Picking the right parents matters, because all gains come incrementally from that start point,


A couple I can think of are stroke volume (referenced a lot in terms of VO2) and mitochondrial density in muscle tissue (referenced a lot in terms of Z2 training).

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Whether you are 150lbs or 205lbs, the first thing you need are excellent genetics to get to a 400w FTP. The changes you need are the same changes a 150lb person needs, and muscular strength isn’t a significant contributor. As has already been said in a few different ways, the central aerobic system is the biggest driving factor for aerobic power and extra muscle mass does little to help there.

And many lightweight riders put out much more than you, but on average larger people certainly have more more power that smaller people (all else being equal). While being a bigger human does come with some aerobic advantages over a smaller person, it doesn’t scale. A 200lb person does not have a 33% bigger heart, lungs, blood/plasma volume, etc. compared to a 150lb person. Again, as much as strength can help you in anaerobic efforts, it’s contribution to aerobic power is not significant unless you get into edge cases. So, the extra muscle mass is useful in some situations and basically dead weight in others. Pick courses, tactics, and racing disciplines accordingly.