## Friday, February 05, 2010

### 5cancellara

A reader sent me an interesting page on the energy requirements involved in unicycling. Quite simply put, two riders, one skilled and one less skilled, show different efficiencies operating the cycle.

Skilled unicyclists devote more energy to going straight than they do trying to stay in balance through precise timing of corrective energy provision, while less skilled riders show the opposite scenario, which is why most of us lose out quickly and fall.

To keep a unicycle in balance, a correcting energy has to be supplied at some frequency for proper dynamics of the system. As far as steering is concerned, the main aim of balancing comes from steering in the direction to counteract a lean.

It will be interesting to study at what frequency skilled riders supply corrective energy to stay in balance. This is apparently done so that the small angular displacements lead to small energy expenditures. The estimation by the author is that 100 calories of energy is supplied by the rider per hour to aid in the balancing act.

Energy output per hour of various means of movement - bicycling, unicycling, walking etc.

The trick seems to be in finding the right balance between ranges for the angle of tilt the rider and his bike makes with the vertical. Too much an angle means you may go faster because of the squared relationship with gravity but it'll take more energy to raise your center of gravity up to the balance point. Too less an angle might mean you're perfectly in balance but you're moving slow.

I haven't ridden a unicycle but I'm wondering what you guys think. How do you balance yourself?

RELATED RESOURCES :

Four Part Series : Dynamic Stability Of Bicycle Design
Efficiency In Inefficiency : Walk Or Pedal Up A Steep Hill?

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1. The energy expenditure per hour listed on the plot for 12 and 24 hours on a bicycle is curious. Coma for the second 12?

Of course, moving up and down doesn't necessarily cost the energy of the vertical displacement, which is why an ideal pendulum will continue doing so perpetually. However, it seems in this instance it may be a decent approximation.

I organize a hillclimb series and we regularly get unicyclists. For example, Steve Nash did a 27:11 up Old La Honda Road. He probably would have been around 20 minutes on a bicycle, I'd guess.

2. Don : Unicycling up a hill.. Are you serious? Hardcore.

3. I don't unicycle, but I suspect unicyclists aren't too concerned about their energy expenditure while riding :-)

4. I am an avid unicyclist and the energy expenditure of riding my 29-inch wheeled uni feels much less than running, but it's about the same speed (used to be a long distance runner). Once you've achieved a certain competency in unicycling, you don't really pay much attention to the balancing part. But, the learning curve was steep. Thanks for the explanations.

5. I would also guess that the size of the wheel makes a difference, I would think that the larger the wheel is the more like having a larger gear on a bike, can anyone verify that? I have been riding a unicycle for 6 or 7 years but haven't ridden anything larger than a 24-inch. I agree the competance of the unicyclist makes the difference.

Thank you. I read every single comment.