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Could someone answer this for me please?
If a rider is putting out 300 watts and weighs 90 kg, how much faster would he be (all other factors like hills/aero etc disregarded) if he lost 15% of his body weight?
Assuming the loss is all fat, and the power output would remain the same.
Thanks.
a non scientific shit load! only evidence being I used to be quite a handy racer at 83kg, I'm now 93kg and can barely climb the stairs!
Thanks all, so around 1 minute over 30km, 64.xx mins vs 63.xx mins, or between 1 and 2 %.
Not as much as I thought it would be.
Largely because weight ain't all that compared to aero.
Weight doesn’t make “that “ much of a difference on flat roads. However put some hills into the equation (especially long ones) and w/kg is king
The two main sources of drag are aero on the flat and gravity on hills. If you disregard those, basically no difference. On the flat, the difference will be tiny because it will mostly just be a small reduction in aero. On a steep climb, massive because it's purely power to weight. You can't calculate a specific percentage without knowing the specifics of the terrain. Also, if you lose 15 kg, it's unlikely that your fitness and power output won't be affected in the real world.
On the flat is negligible. Sorry. On hills it’s a modest amount.
Wish i'd never opened this page... i've lost my only remaining excuse 🙁
~32secs up a minimum Strava cat4 climb (1.65 miles @ 3% 262ft), with bike/water/clothing/tools/food etc. being a conservative 12.5Kg in addition to rider weight.
Could someone answer this for me please?
If a rider is putting out 300 watts and weighs 90 kg, how much faster would he be (all other factors like hills/aero etc disregarded) if he lost 15% of his body weight?
Assuming the loss is all fat, and the power output would remain the same.
Just quoting so I can reference.
You say hills disregarded? Hills are probably where that kind of change would be noticed the most. If it’s not hills and flat, then what kind of conditions? An ultra? A time trial? A road race where you can sit in the bunch?
My guess is you weigh 90kg and are trying to lose 15% fat while training. This is fully possible and you should be able to keep pretty close to the current muscle mass you have if you follow a diet with protein in every meal and eat 5 or 6 times a day (we’re not being bodybuilders here but protein is very important).
In the training process you will likely (obviously) gain more power, so wherever you got that 300 figure from I don’t know ....FTP? It will likely rise a bit anyway over a few months.
To give an estimate, I weighed 68kg last year at the start of heavy training. With good training and diet my weight went down to 64kg over about 4 months, but I only lost 300g of muscle mass. My times on all out climbs that would have taken me about 8.5 or 9 minutes went down to about 7.5 minutes at about 400 - 440 watts , about 550watts max.
There was a big difference on long climbs too (25 to 30 minute climbs), but for ultra road races it made a big difference for me. I’d be curious to know what you’re training for.
Just to add it really depends on your own body type and natural ability on flats versus hills etc. Some power riders will never be great in the hills but they can churn out a high wattage on the flats hour after hour. Goes back to the 300 figure you gave... it’s a sub threshold figure for me and a lot of riders, so you should be able to stay in that zone for quite a long time. But hard to know with little to go on.
Thanks all.
Yes, it's my weight, and it is coming off.
This year is my first back CX racing for 15 years, and I'm finding it really tough.
I am getting better, and am almost catching someone who was always around 3 minutes faster than me over the race distance, roughly 5% faster.
I have lost around 5kg now, and really should be weighing 80kg, though a more realistic goal would be 85kg.
I just wanted to have a rough idea of what weight loss would do, and clearly I will be gaining some muscle while training a little more, but the main focus is weight loss, so I can fit into 32" jeans again!
At the same power output a lighter rider will be much faster up a hill. On the flat, weight has much less of an effect.
At 59kg I struggle on the flat. Most other riders are stronger. On the hills, being light is a big advantage.
For CX, weight loss will definitely make a difference because even if it's flat, you're accelerating out of corners all the time, and rolling resistance (which does depend on weight) is rather more significant than on tarmac.
I’d agree for cx and mtb it makes much more of a difference than road.
Also your ability to recover from sprint efforts is more important than steady state stuff imo.
clearly I will be gaining some muscle while training a little more,
Not a huge amount, unless you’re on creatine and doing heavy resistance training at the same time. Usually I would say you build muscle in the gym before hitting the bike hard, the two don’t go together so well when full on.
Also - Most of the long term muscle mass you develop up until your early 20s, so depends on age.
Common misconception that training equals muscle mass. There will be visual difference in tone from fat less but not a massive amount of muscle gained (from my experience, and body testing on fancy equipment throughout the season).
Not a huge amount, unless you’re on creatine and doing heavy resistance training at the same time.
Creatine has no effect on hypertrophy. It enhances explosive power on athletes who are deficient in their natural level by providing more phosphate ions which can be used in the ATP process. However, once you're up to saturation, taking more has no effect - which is why it only works for some people.
Creatine has no effect on hypertrophy
Yeah I should have made the emphasis more on resistance training. Although, I have noticed myself that when on creatine, my weight increases by about 2kg when training heavily on the bike 6 days a week with maybe 2 light body resistance workouts and I do look bigger (some people argue this is pure water weight). Some of this weight drops off the week or two before a big event as I’ll lower the creatine a bit then. But I’ve heard and read support that creatine can also help for longer distance and endurance athletes as it helps store more fluid in your muscles and throughout your body. Although the main use for most people has been for power.