energy and cadence

Here’s the setup:

There are 2 identical paddlers using identical boats and paddles. They paddle a 1 mile course and start and finish at the same time. One paddler used half as many strokes as the other.

Does it mean that the paddler who used half as many strokes then had to use twice as much energy in those strokes to arrive at the destination at the same time as his partner?

Or is there more going on, such as utilizing the boat’s ability to glide between strokes which would make the energy output something less than double?

If 1 train
leaves Chicago at 6:00 pm and another leaves New York at 3:00 pm is there a sound when they collide if no one is around to hear it?


It would probably be more like paddler B as using 90% as many strokes as paddler A. Still, its a balance point every paddler who wants to paddle faster has to look for. If you want to achieve a faster and faster cadence, beyond a certain point, you can only do it by going to a shorter stroke – and maybe a smaller blade. If you want to maintain the same speed with a slower cadence, you have to take a longer stroke with a bigger blade. I’m guessing the most efficiency is gained by keeping the kayak at as near a constant speed as possible. At a certain point, a slower cadence will result in acceleration when the blade is in the water and deceleration each time the blade leaves the water – and this sounds like more work. By this theory, to go faster, minimize glide and have a working blade in the water as close to 100% of the time as possible.

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Energy is defined as Force x Distance.

In the case you postulate, the distance is the same. Because the time for both boats is also stated to be identical, the force must also be identical.

Thus the energy USED TO ACTUALLY MOVE THE BOATS is the same.

I suspect that you really want to know about the energy burned by the paddlers. This is the system efficiency. How many calories burned to produce the same result. This total system efficiency is composed of several parts; such as the metabolic rate of the paddlers and the efficiency of the paddle.

Since you have stated that the paddlers are identical, it must be a difference in paddle efficiency. Perhaps one was using a wing while the other was using a broom stick.

Obviously a broom stick is much less efficient than a wing paddle. If a broom stick is half as efficient as a wing, then yes, the broom paddler would use twice the energy to produce the same result as the wing paddler, all other factors being identical.

I Got It!

– Last Updated: Apr-13-04 9:56 PM EST –

One paddler took little bitty strokes. The other paddler took big manly strokes. They burn the same number of calories.

Now what is the value of X?

And how many years does farmer Brown get for bestiality?

look at power
Say that they are not going at top speed, just cruising. That takes the paddle out of it more. Power is equal to force x velocity. Since the boats are traveling at the same speed, the power to move them is the same. At the end of the paddle the one paddler needs twice the force as the other since his cadence is half as fast. The optimum cadence for best efficency will depend on the paddle and the paddler. A slower cadence will transmit more force thru the paddle shaft and paddlers joints.

This is like one cyclist spinning at a faster cadence. It takes less muscle but taxes the cardiovascular system more.

strokes per minute
In the Force x Distance equation, there is a big factor missing: Technique and efficiency. How one applies force and the different muscles used all affect how fast the boat goes, not just the calories burned. Recently through new instruction, I saw a large gain at a similar heart rate on a speedstroke erg. I was getting better rotation in the core muscles and using less arm strength.

I agree with the poster that the concept of 100% force applied and less glide would be the fastest. Therefore to go faster, the paddler has to do more strokes per minute-efficiently, not less. If indeed a paddler covered the same distance in 1/2 as many strokes, then the paddler who is stroking more, is far less efficient in his/her stroke, because practically that paddler should be faster (less time for the boat to slow down). K-1 marathon paddlers are up over 80 spm in long distance events.

I have been reading in Total Immersion that for swimmers that the opposite is true. Taking less strokes and elongating the body adds more speed than upping the stroke count.

By the same token,

– Last Updated: Apr-14-04 7:25 AM EST –

if a man goes into a forest and makes a statement, and there is no woman around to hear it, is he still wrong?

Seriously, though, the work equals force time distance equation would apply, if all other parameters were equal.

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per stroke

The slower-stroking paddler needs twice the force per stroke to keep up.

The average force per time, ie power is the same, as you said.

Because the strokes will be shorter, the work (force x distance) will be the same.

I’m 5’4". How in the heck do you “elongate the body”???

I agree
I wasn’t disagreeing with you, I just wanted to present it a different way. I also didn’t want people to get hung up on paddles.

I usally paddle with a 3" wide greenland paddle. When I go back to my Epic or Onno I can really feel the difference in the amount of force transfered to the water and thru my arms. Also the euro paddles can accelerate faster than an unextended gp. My speed with the different paddles is similar, but I perfer the feel with the greenland paddle and a higher cadence.

I the real world one can talk about paddles and technique, but that doesn’t change the physics behind it. If it is a gp, wing or spoon paddle; half the force is transfer by the one with twice the strokes.


Where the paddle meets the water

The force x distance equation discussed here applies at the point where the paddle tranfers the power to the water.

You are correct that technique has a large influance in the conversion of food in the stomach to force applied to the paddle.

read the book for getting taller
Sanjay had posted about it earlier this year. But it is for swimming not kayaking, sorry if that was confused.

Total Immersion

by Terry Laughlin.

I’ve just started it and probably won’t really get to try out the ideas until next fall, as the paddling season has pretty much taken over any swimming right now. the gist of it is about making yourself longer with your reach, presenting less of your body (like a thinner kayak) for less resistance, and taking less strokes and more glide. At 5’ 4" with your arms extended, you become an over 6’-7’ swimmer, nice eh?

One thing that’s readily apparent when I paddle with most new kayakers: the novice will swing away while I
can match one stroke to the other paddler’s several strokes. That’s with the exact same model and length of paddle. The clue is in the lack of efficiency, overpowering the blade making it slip, failing to keep the blade parallel to the direction of effort.

Either that or its magic. Nothing to do with the person being weaker, because more strokes implies greater transfer of energy. If that paddler is weaker, but lighter, and in a narrower boat, properly executed strokes would make the boat accelerate. The solution is not to paddle harder nor would going high or low angle change anythin, except how much energy the person fritters away.

Technique only comes with practice, and I don’t practice enough ; ).

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Shame on you. It isn’t hard.

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Properly used cadence can be almost an art form, like Ballet.

Put that against someone with no technique who tries to power through his stroke and the cadence person will still not be breathing hard after that mile.

Moving a kayak is an added on skill. You do not get to speed in one massive stroke, you build to it, which will burn less energy. Knowing how your boat can add on a little more with each stroke does not mean paddling as fast as you can. That means that half of your strokes are probably wasted because you are flailing with your paddle.

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Thank. I’ve figure that out through the many forum exchanges, and I think you’ve explained it very succinctly.