Weights for hills/sprints

Interesting thought.

One end of my apartment complex is a VERY steep hill. I haven't actually measure it for grade, but it has to be 25-30 degree angle, which is a grade % I'm scared to even mention.

You CANNOT stand on the thing easily, nor can you ride part of the way up and stop without turning to the side, etc. It's a little scary riding back down it also.

It's not very long, probably less than 100 yards, but one hell of a test. I've done it once in a 39-25 gear (it's a dead end drive). Impossible to actually sit any of the time, I just start at the bottom standing, lean over the bars and grind.

As you mentioned, it feels much more like doing a set of squats than anything approaching cycling. I have no idea what kind of power I'm generating to climb it, but I highly expect I'm using fast-twitch fibers to do it...which would benefit from weight training.

Incidentally, the time I did try it.. I didn't make it all the way to the top, only about 3/4.

I should be receiving my Polar power unit next week, I'll have to test it out there and see what it says.

John

Mansmind said:

I should be receiving my Polar power unit next week, I'll have to test it out there and see what it says.

John

Them polar power units are not accurate!

velomanct said:

Since the above weight thread has been closed, maybe we can continue it here.

I made an interesting observation with my powertap. Climbing steep (12%+) hills in a normal low gear of 39x23/25 requires about TWICE as much torque as sprinting on a flat road at race speed.

are you looking at the torque from a Power Tap hub? If this is the case, this is the torque in the hub and different to what you're requiring at the pedals

I'm not sure of your power stats, however using mine, on a 16% grade at 380 W, and ~ 15 km/h, in 39 x 23 i'm at ~ 70 revs/min. This requires me to apply a force of ~ 305 N (~ 31 kg between both legs).

When 'sprinting' i can just hit ~ 900 W at ~ 110 revs/min. This requires a force of ~ 460 N (~ 47 kg between both legs). However, it's likely, that i probably hit that peak power at a lower cadence, and it's definite that the forces are even higher from a standing start effort.

If i recall correctly, you're a good sprinter, so if you say did 1400 W at 130 revs/min your required force on the pedals would be 605 N (~ 62 kg between both legs).

Quoted post said:

We all know that weight training improves sprinting ability, but the great debate is if it improves your ability to climb hills.

it's very unlikely except in untrained or low fitness groups. Whilst climbing you're limited by factors such as MAP, and LT, which are cardiovascular and metabolic, and hill climbing isn't likely to be affected by strength unless you're very weak.

Quoted post said:

I climbed a local 16% hill today in my 39x23 at about 8mph. There was some serious pressure on the pedals, something that no frail, old lady could do 😉
I climbed this hill on my fixie last winter, 39x14. THAT was darn close to a heavy squat workout.

i didn't say that a frail old lady could do this! i actually said that it would be this group that would be strength limited!

ric

zaskar said:

Them polar power units are not accurate!

I've seen evidence both ways, enough so that I'm willing to find out for myself.

Regardless of accuracy though, it should still give me at least "consistent" results to gauge training by.

Jury is still out, but I'll be sure to let you know how it works.

John

Quoted post said:

i didn't say that a frail old lady could do this! i actually said that it would be this group that would be strength limited!

ric

My mistake, I got a little confused.

Yes, I use a powertap hub. Can you further explain about the torque?
I think I understand. On my last ride I put in the 53x12 at a near standstill and push as hard as I could. Max torque readout was only in the 300s inch lbs. Then I put it in the 39x23 and from a standstill I push as hard as possible and got in the 800s. So the force on the pedals was about the same, but because of the different gear, the hub recorded a lower torque using the big gear.

You are speaking in terms of force which is the same as pressure on the pedals I assume. This is seperate from the speed at which these forces are applied to the pedals. When climbing that steep hill at 60rpms, my torque is in the 400 inch lbs range. During a flat sprint I average around 250 inch lbs(peak of ~350) at 115rpms.
So I am climbing at lets say 500watts(short climb!), and sprinting at 1400watts. The reason the torque is much higher during the climb is because of the low rpms.

I think I am figuring out why weights only help for sprints. Even though there is more pressure on the pedals during a very short, very steep climb, it is not a maximal effort such as a sprint. (unless you sprint the climb)

I think the only way weights could help for climbing is if you ride steep hills at a less than full effort. That way you would not be limited by your fitness, and the added strength would make the climb "feel" easier.

I guess I answered my own question. Once you go into oxygen debt on a climb, it doesn't matter how strong you are.

The bottom line is: weights only help for maximal efforts under 90 seconds, no matter what the terrain.

All I'm doing at present is weights till I feel my knee gets more stable. The crackling noise has reduced somewhat and I'm also applying glucosamine cream, plus oral doses of tablets. Too much climbing over Summer.
I just started doing deadlifts (never done them before). My plan is to deadlift with moderate weights to strengthen my lower back. My cycling level will be down when I kick in again but there's no way I want to risk any serious knee damage, so I'm just keeping active meantime.

velomanct said:

Since the above weight thread has been closed, maybe we can continue it here.

I made an interesting observation with my powertap. Climbing steep (12%+) hills in a normal low gear of 39x23/25 requires about TWICE as much torque as sprinting on a flat road at race speed.

We all know that weight training improves sprinting ability, but the great debate is if it improves your ability to climb hills.

The pressure on the pedals during short steep climbs is more than during sprints, so why can't weight training be of benefit? Even during moderate grade long climbs, torque(or pressure on the pedals) is at least as great as during a flat sprint.

I climbed a local 16% hill today in my 39x23 at about 8mph. There was some serious pressure on the pedals, something that no frail, old lady could do 😉
I climbed this hill on my fixie last winter, 39x14. THAT was darn close to a heavy squat workout.

velomanct said:

Yes, I use a powertap hub. Can you further explain about the torque?
I think I understand. On my last ride I put in the 53x12 at a near standstill and push as hard as I could. Max torque readout was only in the 300s inch lbs. Then I put it in the 39x23 and from a standstill I push as hard as possible and got in the 800s. So the force on the pedals was about the same, but because of the different gear, the hub recorded a lower torque using the big gear.

this torque you see from the Power Tap is hub torque and not force you apply to pedals. You need to multiply it out depending on gearing and crank length. You need to calculate torque differently if you want to know what the force on the pedals are.

Quoted post said:

You are speaking in terms of force which is the same as pressure on the pedals I assume. This is seperate from the speed at which these forces are applied to the pedals. When climbing that steep hill at 60rpms, my torque is in the 400 inch lbs range. During a flat sprint I average around 250 inch lbs(peak of ~350) at 115rpms.
So I am climbing at lets say 500watts(short climb!), and sprinting at 1400watts. The reason the torque is much higher during the climb is because of the low rpms.

these are hub/wheel torques that you've quoted and aren't useful, other than converting them to pedal force i'm not sure what you can do with these data.

500 W at 60 revs/min = 468 N, while 1400 W @ 115 revs/min = 684 N, thus force is higher when sprinting (and would be considerably higher still doing a standing start sprint).

ric

ric_stern/RST said:

this torque you see from the Power Tap is hub torque and not force you apply to pedals. You need to multiply it out depending on gearing and crank length. You need to calculate torque differently if you want to know what the force on the pedals are.

these are hub/wheel torques that you've quoted and aren't useful, other than converting them to pedal force i'm not sure what you can do with these data.

500 W at 60 revs/min = 468 N, while 1400 W @ 115 revs/min = 684 N, thus force is higher when sprinting (and would be considerably higher still doing a standing start sprint).

ric

Would a 1:1 gear ratio mean that the torque at the cranks is equal to at the hub?
I guess you would then need to take into account the crank arm length to figure out what the force on the pedal is.

ric_stern/RST said:

it's very unlikely except in untrained or low fitness groups. Whilst climbing you're limited by factors such as MAP, and LT, which are cardiovascular and metabolic, and hill climbing isn't likely to be affected by strength unless you're very weak.

ric

I reckon something definitely changes as climbs become steep. Take my friend Rob and me. We're normally within one or two kilos of each other in weight, though I'm a bit taller than him. Time trialling individually on the flat, or riding two-up, I usually beat him. Thus, assuming my aerodynamics aren't substantially superior to his, my power, and hence power-to-weight ratio, should be greater than his. However, on climbs of around 5-10% we're normally dead level, cannot be split apart. And then, once they get really steep, 15% or more, he'll just ride away from me, every time - even when I'm a little lighter than him. What is it that makes this difference when the going gets steep?

duncan

ric_stern/RST said:

I'm not sure of your power stats, however using mine, on a 16% grade at 380 W, and ~ 15 km/h, in 39 x 23 i'm at ~ 70 revs/min. This requires me to apply a force of ~ 305 N (~ 31 kg between both legs).

When 'sprinting' i can just hit ~ 900 W at ~ 110 revs/min. This requires a force of ~ 460 N (~ 47 kg between both legs). ric

Ric,

I think you should note that you are talking about average pedal forces. Peak forces are around double what you've mentioned.

I just ran a quickiy on Analyticcyling using a 16% grade at 70rpm, 8mph (3.5 m/s) and got the following:

Average Pedal Force 383.6 kg m/s2
Effective Pedaling Range 70. degree
Effective Pedal Force 986.4 kg m/s2
Speed 3.50 m/s
Power 485.0 watts

Average pedal force is only 39kg (divide pedal force by acc. due to gravity to get kg)

Effectve pedal force comes out to just over 100kg force over those 70o - for each leg - that's about 220lbs for a single leg over those 70.

Comments?

beerco said:

Ric,

I think you should note that you are talking about average pedal forces. Peak forces are around double what you've mentioned.

I just ran a quickiy on Analyticcyling using a 16% grade at 70rpm, 8mph (3.5 m/s) and got the following:

Average Pedal Force 383.6 kg m/s2
Effective Pedaling Range 70. degree
Effective Pedal Force 986.4 kg m/s2
Speed 3.50 m/s
Power 485.0 watts

Average pedal force is only 39kg (divide pedal force by acc. due to gravity to get kg)

Effectve pedal force comes out to just over 100kg force over those 70o - for each leg - that's about 220lbs for a single leg over those 70.

Comments?

Beerco, that's a good point. Effective pedal force is going to be considerably higher than average. It looks like you are interperating the figures from analyticcycling.com as for one leg only. This is from the forces on rider - given speed page.
"The effective pedaling force, Feff, gives the force in each of TWO legs that is required to give the same average force, Fav, while pedaling in only a portion, Eff, of a full rotation of the pedals."

So I think your figures are double what they should be. The watts calculator determines total power needed for the situation, so all the other figures such as kg/m2 are the combination of both legs.

velomanct said:

Beerco, that's a good point. Effective pedal force is going to be considerably higher than average. It looks like you are interperating the figures from analyticcycling.com as for one leg only. This is from the forces on rider - given speed page.
"The effective pedaling force, Feff, gives the force in each of TWO legs that is required to give the same average force, Fav, while pedaling in only a portion, Eff, of a full rotation of the pedals."

So I think your figures are double what they should be. The watts calculator determines total power needed for the situation, so all the other figures such as kg/m2 are the combination of both legs.

You're misunderstanding his text. It's the average force required over the effective pedaling range (70o each) for each leg to get the average power for one full rev (360o) for both legs.

e.g. the numbers I entered into AC:

(2x(986x70))/360=383.44444444444444

So, your average force over those 70o is really around 220lbs/leg. Peak forces might even be higher. On the other hand, hopefully one won't have to put out 480w for too long at 70rpm! Or for some, it might mean walking 🙁

beerco said:

You're misunderstanding his text. It's the average force required over the effective pedaling range (70o each) for each leg to get the average power for one full rev (360o) for both legs.

e.g. the numbers I entered into AC:

(2x(986x70))/360=383.44444444444444

So, your average force over those 70o is really around 220lbs/leg. Peak forces might even be higher. On the other hand, hopefully one won't have to put out 480w for too long at 70rpm! Or for some, it might mean walking 🙁

this is on a 16% climb at 8mph, 60rpms, with a total bike+body weight of 90kg.
Average Pedal Force 480.2 kg m/s2
Effective Pedaling Range 70. degree
Effective Pedal Force 1234.9 kg m/s2
Speed 3.58 m/s
Power 528.0 watts

This is the combined effective pedal force of both legs. Why would they only give you figures for one leg? 1234kg/m/s2 equals 125kgs or 275lbs. Divide that by 2 and you get 137lbs of force per leg, in the effective 70 degree range. I am sure peak forces are higher.

beerco said:

Ric,

I think you should note that you are talking about average pedal forces. Peak forces are around double what you've mentioned.

I just ran a quickiy on Analyticcyling using a 16% grade at 70rpm, 8mph (3.5 m/s) and got the following:

Average Pedal Force 383.6 kg m/s2
Effective Pedaling Range 70. degree
Effective Pedal Force 986.4 kg m/s2
Speed 3.50 m/s
Power 485.0 watts

Average pedal force is only 39kg (divide pedal force by acc. due to gravity to get kg)

Effectve pedal force comes out to just over 100kg force over those 70o - for each leg - that's about 220lbs for a single leg over those 70.

Comments?

I haven't had time to check those figures, as i've been somewhat busy. Yes, those figures (i quote) are the average pedal force, with peak force about twice the average. or in other words the peak force of each leg is about the same as the average from both.

that being said, it doesn't intrisically change anything as people a) generate a much higher force doing a standing start sprint -- even if you stamp on the pedals from stationary the forces are way higher than anywhere else, and b) we can produce more force sprinting than riding uphill or in a TT etc, it doesn't matter whether you look at peak or average, we can all sprint harder than we can ride steady and c) we know that 1) on average matched controls are as strong as elite cyclists and 2) that untrained but moderately active (e.g.) students can on average produce a similar or same peak power as trained endurance cyclists*

*in some unpublished work we looked at [cycling] peak power output using a 20-stg SRM Science comparing peak powers of sports science students (subjects were sedentary, football=soccer players, rugby, runners (sprint and endurance), downhill skier, fitness (weights/gym), and cyclists). in terms of cyclists we had in elite world champions and record holders and average cyclists such as myself (2nd cat). i can't recall the exact ordering of results, but the cyclists came down the list, with soccer players in general coming out at the top. eventually, the lab record was beaten and as far as i'm aware not been topped yet, by a sedentary person at the time > 22 W/kg (he now rides several hours a week).

Ric

velomanct said:

this is on a 16% climb at 8mph, 60rpms, with a total bike+body weight of 90kg.
Average Pedal Force 480.2 kg m/s2
Effective Pedaling Range 70. degree
Effective Pedal Force 1234.9 kg m/s2
Speed 3.58 m/s
Power 528.0 watts

This is the combined effective pedal force of both legs. Why would they only give you figures for one leg? 1234kg/m/s2 equals 125kgs or 275lbs. Divide that by 2 and you get 137lbs of force per leg, in the effective 70 degree range. I am sure peak forces are higher.

let me try and explain better.

An average pedal force of 480 kg-m/s^2 is required over the full 360o to get an average power of 528w. Or to put it another way (480 x 360)/360 (we're taking 480w per degree x number of degrees we've got 480 over total number of degrees)

The effective pedaling range is 70o PER LEG. The effective pedaling force is the force required by each leg in those 70o where it's active to get an average force of 480 over the full 360.

As an example, if we take 1234 x 70o (effective pedaling range) and divide by 360 (full rev) we only get 239 kg-m/s^2 or half of the average pedal force which doesn't get you the 528w. However, if we multiply by two to add the contribution of the other leg, you get the full 480 kg-m/s^2. This shows that effective pedal force is a "per leg" contribution. (trust me on this one, I've had lots and lots of calc, statistics and physics).

By the way, to go from kg -m/s^2, to kg weight, divide by 9.8 m/s^2 (acceleration due to gravity). So in your example, each leg has to press about 277lbs over the 70o that its working.

ric_stern/RST said:

I haven't had time to check those figures, as i've been somewhat busy. Yes, those figures (i quote) are the average pedal force, with peak force about twice the average. or in other words the peak force of each leg is about the same as the average from both.

In general, I agree. I think the point that Velomanct was making though was that once the road turns pretty steep, strength may be an issue.

ric_stern/RST said:

*in some unpublished work we looked at [cycling] peak power output using a 20-stg SRM Science
Ric

Just a reminder BTW, the SRM, even the science version, is not capable of measuring power within one pedal stroke, irrespective of SRM tells you with their sample rate (i.e. even at the 100mS sample rate they're just interpolating within the pedal stroke).

Without a high data rate crank position sensor, the SRM can only give you peak torque within a stroke and average power for an entire 360o.

Tom Compton of AC has stated that in his calculations for riding on the flats, crank acceleration is pretty low (i.e. you can assume a constant velocity and use it to calculate instantaneous power quite accurately). IIRC though, he did admit that at low rpm in a hill situation, crank acceleration is pretty dynamic.

beerco said:

In general, I agree. I think the point that Velomanct was making though was that once the road turns pretty steep, strength may be an issue.

i don't think so. as pointed out, peak power the forces are greater. even if i rode up some steep hill at 400 W (5.9 W/kg) at 40 revs/min in 39 x 23 (8 km/hr) there's still less force than sprinting. i'm not sure how steep that hill would have to be, but i'm guessing steeper than 25%...

Quoted post said:

Just a reminder BTW, the SRM, even the science version, is not capable of measuring power within one pedal stroke, irrespective of SRM tells you with their sample rate (i.e. even at the 100mS sample rate their just interpolating within the pedal stroke).

apologies if i alluded to this, but i wasn't talking about within a pedal stroke.

ric

beerco said:

let me try and explain better.

An average pedal force of 480 kg-m/s^2 is required over the full 360o to get an average power of 528w. Or to put it another way (480 x 360)/360 (we're taking 480w per degree x number of degrees we've got 480 over total number of degrees)

The effective pedaling range is 70o PER LEG. The effective pedaling force is the force required by each leg in those 70o where it's active to get an average force of 480 over the full 360.

As an example, if we take 1234 x 70o (effective pedaling range) and divide by 360 (full rev) we only get 239 kg-m/s^2 or half of the average pedal force which doesn't get you the 528w. However, if we multiply by two to add the contribution of the other leg, you get the full 480 kg-m/s^2. This shows that effective pedal force is a "per leg" contribution. (trust me on this one, I've had lots and lots of calc, statistics and physics).

By the way, to go from kg -m/s^2, to kg weight, divide by 9.8 m/s^2 (acceleration due to gravity). So in your example, each leg has to press about 277lbs over the 70o that its working.

This is getting quite confusing. It sounds like you know your stuff, so you are probally right.

277lbs is quite a lot of force for each leg!