Body in motion, body at rest: bike training Newtonian style

A black and white photo of a woman jumping on a trampoline, her skirt billowing, with a boy holding a balloon and watching her.

Isaac Newton, one of the main developers of modern classical physics and co-creator (along with Gottfried Wilhelm Leibniz, a philosopher) of the calculus, didn’t ride a bike.  They didn’t have them then.  But Newton did have many things to say about motion.  Here’s one of them:

Text reading "an object at rest will remain at rest unless acted on by an unbalanced force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force. This law is often called the law of inertia.

Newton really knew what he was talking about.

As science nerds like to say when they’re having some fun, inertia isn’t just a good idea; it’s the law.  Yeah, yeah, I know that people say this about gravity instead of inertia, but it works here too.

After a long period of being a body at rest, I’ve overcome inertial forces and become a body in motion, in particular on two wheels on my bike, and two feet in yoga class (or one foot, or even no feet when I’m hanging out upside down, which is a lot of fun).  And it feels good.

Last week I rode more than 100 miles (albeit not all at once, but still), which was more than I had ridden in I don’t know how long.  Yay!

Then, last Monday I rode 38 miles with my friend Pata, and did not pay proper attention either to fueling or hydration.  Bad me!  As a result I started to feel a bonk coming on.  Every cyclist has experienced this– sudden drop of energy, vision narrowing, oceans of emotion, and the irresistible need to stop RIGHT NOW for coca cola, a snickers bar, and some hostess cupcakes on the side.  That is, you need an infusion of simple carbs.  NOW.  Not later.  NOW.

Maybe this is what Newton meant by being acted upon by an unbalanced force.  It certainly felt like a force, and I was definitely unbalanced.

I spied a pizza place and told Pata that we were stopping to get me a coke.  Wordlessly she followed, then offered to get it herself, but I was already off the bike and striding at full speed into the restaurant.  I got a nice, ice-filled large coca cola, and the person behind the counter told me I could get free refills.  I obviously stopped at the right place.

It’s astounding, the transformation that happens after ingesting about 1/2 liter of coke in a short amount of time.  We got back on the bikes and all of a sudden life was worth living again, and I felt a surge of energy.  Pata, ever the experienced cyclist and good friend to me, made me ride more slowly the rest of the way back.  Thanks, Pata!

However, after my great week of cycling, following by a great day of cycling, I succumbed to Newton’s third law:

Newton's third law of motion, which reads "for every action there is an equal and opposite reaction".

I fell into a big slump from Tuesday to Friday.  Partly I was under the weather (I have GERD, which means I have indigestion and acid reflux, for which I take meds).  The GERD had flared up, which wasn’t fun.  I was also low energy.  That, combined with clouds and rainy weather off and on, kept me off the bike for 4 days.

Of course, now that I was lying around for several days, there was the problem of combating the inertia of my body at rest in order to get back on the bike.  Luckily, I have a lot of very nice friends who like to ride bikes with me.  Yay friends!

Jessica and I rode on Saturday.  The weather was sunny and not too hot.  I had packed plenty of energy food in my jersey pockets and had eaten before we left.  We did a nice route through leafy green woodsy roads, dotted with very nice houses and the occasional horse farm.  This route also had some oh-so-gentle hills.

This was where I encountered Newton’s second law:

Acceleration is produced when a force acts on a mass. The greater the mass (of the object being accelerated) the greater the amount of force needed (to accelerate the object).

It just so happens that my mass is greater than the mass of my cycling friend Jessica, who rode easily up those very gentle rollers.  My mass is also greater than it was 3 years ago, and my force is less strong.  So, I used all the force I had just to maintain net forward motion going uphill.  I knew this would happen, but it’s still discouraging.  According to Newton, my situation gives me two options:  1) reduce my mass; or 2) increase my force.  For me, I think the best option right now is to keep riding and regain the strength and force that I need to get myself up and over hills.  So I’m doing just that.

In two weeks, I’ll be taking on a big challenge:  riding 110K for the PWA Friends for Life Bike Rally, with Sam and a bunch of her very nice cyclist friends.  I don’t know how it will go.  However, because of this upcoming ride I’ve overcome my body-at-rest inertia, increased my force to roll down the road, and bounced back when my reaction to a lot of riding was to do a lot of not-riding.  All as Newton had in mind, if he had ridden bikes.

Sir Isaac Newton on a dirt bike, holding an apple (that's all I could find).

Sir Isaac Newton on a dirt bike, holding an apple (that’s all I could find).

Well, not really.  But humor me.

 

About catherine w

I'm an analytic philosopher, retooled as a public health ethicist. I'm interested in heath behavior change, particularly around eating and activity, and how things other than knowledge affect our health decisions.I'm also a cyclist (road, off-road, commuter), squash player, x skier, occasional yoga-doer, hiker, swimmer and leisurely walker.

One thought on “Body in motion, body at rest: bike training Newtonian style

  1. Sam B says:

    I’m so excited about riding with you! And Sarah. And David. And Judy. And Joh. It will be a blast.

    Liked by 1 person

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