Why leg strength doesn't matter, that much, for road riding - a technical answer

[RecordAceFromNew]

That's the difference between strength and power. You already have the required strength - but whether you can convert that into sustainable power over a given period of time is a different matter. That was the original point - in the original thread...

Ok!

 

[Lee_M]

so what is happening if I'm on a steep hill with my lowest gear and cant turn the pedal?

surely that is a strength question, as I havent even reached my aerobic limit, just my strenght limit

i'd love to be able to climb hills but...

at 16 stone thats an awful lot of watts to produce

 

[Rob3rt]

so what is happening if I'm on a steep hill with my lowest gear and cant turn the pedal?

surely that is a strength question, as I havent even reached my aerobic limit, just my strenght limit

i'd love to be able to climb hills but...

at 16 stone thats an awful lot of watts to produce

You fall over sideways! Under no circumstance may you give up and put a foot down, this shoot is serious and you go until you fail!

Then you buy a cassette with more teeth and try again!

 

[fenlandpsychocyclist]

Why do formula one cars rev four times higher than your average family saloon?
They have x amount of torques, but made four times more often to produce four times the horsepower.

Torque x revs = power.

(Enough of the car stuff).

 

[gavroche]

Let's get some basics out of the way;

• The average person can easily climb a set of stairs for several min without much problem. They may do this slowly but they can climb stairs. This means that people are regularly pushing down with, considerably, more force than their body weight; if you can't lift more than you weight you'd never climb stairs.
• A good national level pro/sponsored rider is going to have maximal outputs of around 6.5W/kg for 5 min. A fit, slightly trained rider will be close to 6.5W/kg for 1 min maximal effort & 3W/kg for 5min.
• A typical trained rider will have a nominal foot speed of 1.25-2.25m/s. On 170mm cranks this equates to approximately 70-125 rpm.
• The more power you produce the higher your cadence tends to be.
• Your peek pedal force is approximately 2.1x higher than your average pedal force across the entire pedal revolution. (I know this is true for me I'm not so sure about other people.)

At 6W/kg, & 70 rpm a rider will be applying enough force to lift 53% of their weight over the entire pedal stroke & applying a force to lift 120% of their weight at the point they're applying maximum force on the pedals. This sort of figure is nowhere near the muscular strength limit for a fit person, let alone a trained athlete. To put into context; For Someone who is 12 stone, such as a certain Mr B. Wiggins, 6.5W/kg equates to 495w.


If we drop to a more typical 3W/kg, 230w for someone who tips the scales at 12 stone & the sort of level that I'd expect a faster commuter to be able to produce, even peek pedal pressure is only producing enough force to lift two thirds of your body weight. Do people really think you need a large muscle mass to achieve that sort of force considering how easily most people accelerate their entire body mass up stairs?

Now all this assumes you're at the lower end of the rpm registers when climbing. Say you climb in the low 80rpm range. Even up a 6.5W/kg you're looking at your maximum pedal force being the same as your body weight, something you should easily be achieving. At 3W/kg it's less than half your body weight.

EDITED: make it a bit more readable.

all that science baffles me. All I know is that the granny gear is my favorite gear when I go uphill.It seems to do the job, slowly mind you, but it gets me there, unless the hill is reeeeeallly steep , then I resort to good old fashion walking.

 

[lukesdad]

Of course we are assuming we are not talking about the young, old or infirm here. To take the anology of the car for a moment. The strength of the conrod has to be such as to deal with the force applied to the piston. Not everybody's skeletal structure may be equiped to handle the forces applied even in cycling.

 

[MrJamie]

Gotta love the sciencey threads like these

I thought peak torque was limited by your bodyweight, doesnt pushing down with way more than your bodyweight just lift you up?

Im dragging round a lot of weight in myself and my bike at about 145kg combined, but never feels like I require more strength, I just suffer a lot up hills in terms of cardio/aerobic fitness but I figure its good training, low gear higher cadence crawling up a hill, so when im lighter ill be able to keep the same torque/rpm in a slightly higher gear and the hills will be over with much quicker too.

Although isnt there something to be said for switching from a higher cadence to out of the saddle grinding possibly in utilising different muscle fibres as well as muscle groups? Does that have anything to do with Cavs finishing power?

 

[lukesdad]

Gotta love the sciencey threads like these

I thought peak torque was limited by your bodyweight, doesnt pushing down with way more than your bodyweight just lift you up?

Im dragging round a lot of weight in myself and my bike at about 145kg combined, but never feels like I require more strength, I just suffer a lot up hills in terms of cardio/aerobic fitness but I figure its good training, low gear higher cadence crawling up a hill, so when im lighter ill be able to keep the same torque/rpm in a slightly higher gear and the hills will be over with much quicker too.

Although isnt there something to be said for switching from a higher cadence to out of the saddle grinding possibly in utilising different muscle fibres as well as muscle groups? Does that have anything to do with Cavs finishing power?

Ah but there is Torque and then there is Torque, which are you torqueing about

 

[black'n'yellow]

so what is happening if I'm on a steep hill with my lowest gear and cant turn the pedal?

surely that is a strength question, as I havent even reached my aerobic limit, just my strenght limit

In principle, the only thing stopping you from turning the pedals will be the inability to generate the power required to ride up the hill. Or you may have the wrong gearing, or the hill might just not be rideable, for the same reason as a vertical wall is not rideable, regardless of how much power or strength you may have....

 

[marzjennings]

I love the title of this thread.

 

[Lee_M]

In principle, the only thing stopping you from turning the pedals will be the inability to generate the power required to ride up the hill. Or you may have the wrong gearing, or the hill might just not be rideable, for the same reason as a vertical wall is not rideable, regardless of how much power or strength you may have....

thats it, the hill is unrideable... thats my excuse from now on thanks!

 

[GrasB]

I believe that was and is my point, per the OP's comment I find difficult to agree with. I also doubt everybody can sustain 500W over extended period even with training, given age, gender, condition etc. all being factors, but that is a different subject.

The point of using 6.5W/kg was it's serious power. As I said in the opening of the thread over 5min it's lower level pro outputs, it's big power. However if you can actually get a cat 3/4 racer who has done proper interval training to warm up & then do a single all out one shot maximal effort run you'd be surprised at how much power they can produce & over what duration. The main issue is actually motivating them enough to do a true one off maximal effort run. Also I'd be surprised if there were that many racers who are near that weight in the lower cats, certainly in Italy I only see the heavy guys once you're into deep into cat 2 territory.

all that science baffles me. All I know is that the granny gear is my favorite gear when I go uphill.It seems to do the job, slowly mind you, but it gets me there, unless the hill is reeeeeallly steep , then I resort to good old fashion walking.

Hey hey hey the thread title is "Why leg strength doesn't matter, that much, for road riding - a technical answer" what did you expect?

Gotta love the sciencey threads like these

I thought peak torque was limited by your bodyweight, doesnt pushing down with way more than your bodyweight just lift you up?

Think about this, Cav is 69kg & can push out 1.6kW. At 140rpm (2.5m/s on 170mm cranks) that's an ave pedal force of 69kg.

Put hiking sticks in someones hands & they'll naturally transfer 30-40% of their weight onto their arms without them even feeling it. So now think about how much you're utilising your arms if you actually feel it in your arms? Also add in that any self respecting roadie will be using some kind of foot retention & suddenly you've got an awful lot of resistance to upwards motion.

 

[poynedexter]

up till last week i was determined to lift weights this winter. now i'm definately not gonna bother. having spent the last 2 outings thinking about the pain in my legs and lungs, and with the progress i've made recently by riding harder, i reckon its all about conditioning and body weight. i'm kinda convinced by all this aerobic talk.

so i've seen my weight go down from 11.5 stone to 11 and now 10st 11lbs. i'm gonna target 10.5 stone as a base weight and cycle more!

i do remember when i raced mx for 20 yrs, lifting weights to increase strength made it impossible to hold on after 5 mins. arm pump city! i wonder was it the same thing. was mx aerobic too

 

[fenlandpsychocyclist]

Gotta love the sciencey threads like these
I thought peak torque was limited by your bodyweight, doesnt pushing down with way more than your bodyweight just lift you up?

You push down with one foot, while pulling up with the other *never leaving the seat*.
Simples ... i do it all the time wearing my work shoes and fairly tight toe-clips.

So in effect i'm exceeding the torque that others create just "standing on their pedals".

One day i'll invest in cleat pedals and shoes, but for now all three of my rides have add-on toeclips.

 

[black'n'yellow]

You push down with one foot, while pulling up with the other *never leaving the seat*.
Simples ... i do it all the time wearing my work shoes and fairly tight toe-clips.

So in effect i'm exceeding the torque that others create just "standing on their pedals".

One day i'll invest in cleat pedals and shoes, but for now all three of my rides have add-on toeclips.

As power level increases, cyclists don't pedal in circles.

Martin cited 1991 research by Ed Coyle, et al, involving regional level competitors and elite racers -- pros and U.S. national team members. Coyle found that elite cyclists pushed down harder and pulled up less than the less-accomplished riders.
Surprisingly, the elite riders were more efficient even though they were pedaling less smoothly. They had a higher percentage of endurance-loving slow-twitch muscle fibers than the regional riders and Coyle theorized that may have skewed the data regarding efficiency.
To find out if Coyle was right, another study examined 8 different riders with similar muscle fiber makeup pedaling with 4 different techniques: (1) their normal, preferred technique; (2) concentrating on pedaling circles; (3) pulling up on the backstroke; (4) pushing down hard. Pedal forces and metabolic costs were measured.
Pulling up was significantly less efficient than the riders' preferred technique. The study indicated that the muscles that flex the leg and allow pulling up the pedal on the backstroke are intrinsically less efficient than those that push down.
How can your pedal stroke be efficient if the weight of the foot and pedal on the backstroke interferes with the power-producing downstroke? As the study put it, force and power at the pedal reflect the combined effects of muscular effort, gravity in the form of the weight of the leg, and accelerating and decelerating the leg during the pedal stroke. In other words, the negative power observed at the pedal on the backstroke is mostly due to gravity, and that negative power is essentially balanced by the weight of the other leg.
So is it worthwhile to concentrate on perfecting your pedal stroke?
Martin maintains that when we pedal we use the spinal cord's neuromuscular programs that allow us to run. Thinking about the fact that these reflexes exist and are useful for pedaling is usually sufficient to ensure a solid pedal stroke.
Broker agrees, saying that he isn't a believer in working excessively on the pedal stroke in training. When he was helping coach the U.S. national team in the '90s he simply gave riders a few cues at the top and bottom of the stroke to help them visualize a smoother "circle." For instance, as the foot nears the top of the stroke, you could think about pushing your knee toward the handlebar. And as the foot nears the middle of the downstroke, use LeMond's timeless advice to pretend you're scraping mud off the sole of your shoe.
Notice that these cues are activated well in advance of when the foot is actually at the top or bottom of the pedaling action. That's because you can't react fast enough to put the movement into action when the foot is farther along. You have to anticipate the proper moment and visualize the cue well in advance due to the speed of pedaling. Think about passing a football. You need to lead a running receiver, and in the same way you must mentally "lead" the foot in order to get the desired action at the right time in the pedaling circle.
Another way to get feedback is to ride a mountain bike up a steep hill with a loose, gravely surface. If you pedal jerkily, pushing down hard, you'll lose rear-wheel traction. The tire will spin abruptly on the loose gravel, causing you to lose momentum and put a foot down. But if you concentrate on pedaling evenly through the whole 360-degree circle, the rear wheel won't lose traction.
Interestingly, said Broker, among all the riders tested over the years at the U.S. Olympic Training Center in Colorado Springs, mountain bikers had the smoothest pedal stroke, even smoother than pursuit specialists on the track. Off-road legend John Tomacwas the smoothest of all.
Fine. Some practice, rather than years spent working on a silky pedal stroke, will make you as smooth as necessary for generating maximum power. But how much practice do you need?