Talking about bike-maths (Galileo would have built sick rhythm sections): when you manual-pump a roller, should the force be directed vertically (to increase your weight as you suggest in Mastering Mountain Bike Skills), or perpendicularly to the backside (so that all the energy is used to push off the ground)?
Provided that our aim is to get as much speed as possible. This issue has been niggling me for a long time…
Thanks for the interesting question. I too have wondered about this.
Here’s my current thinking:
Job #1 should generally be: Balance on your feet. There are exceptions, especially at the top end of the sport, but most of us should focus on light hands, heavy feet. You cannot go wrong.
A proper pump-manual happens when you anchor the bars toward your hips and extend your legs while driving your hips toward your bars. This movement is analogous to gate starts, rowing, power lifting, nordic skiing, lifting furniture and many other forms of human power generation. When you dial in this motion, you can harness a TON of power. But you have to stay balanced and manage the opposing forces through your core.
If you try to push your bike backward into the backside, I think these things will happen:
• You will push yourself forward, off balance.
• You’ll reduce the amount of power you can generate between your hands and hips.
• You’ll be working against yourself. More on that:
If you focus on pushing downward, the slope of the backside will translate some of your downward anger into forward love. Since you just got very heavy, you’re about to get light. That’s perfect, because you can use that lightness over the 2nd roller. Sine wave of love.
More heavy >>> more light >>> more awesome.
On the other hand,
If you push backward, the slope of the backside will push you forward. While you might get a momentary boost in body speed, you’re now on the front of your bike and disconnected from your internal power source. Also, you’ve created less heaviness, so there’s gonna be less lightness … which means you won’t absorb the frontside as smoothly. I can envision lots of ways to handle this situation, but they all seem awkward.
More backward >>> more forward >>> more awkward.
To sum it up:
• Stay in the middle. Crush your feet down while you anchor your bars to your hips.
Know more. Have more fun!
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