Spinning those pedals.

I’ve been giving cadence, that is that rate at which I rotate the pedals, a lot of thought recently. It isn’t mountain biking which has brought the matter to my attention but using my pedal powered boat. In the boat it’s not possible, due to the resistance of the water, to spin the pedals at the kind of rate you do on a bike. About 30 revolutions per minute is easy enough but anywhere above that rate and the work needed rises exponentially. Reading up on cycling and I find that top road riders tend to rotate at 90 to 100 rpm. On my last ride I measured 74 rpm on a level dirt trail but less than this up hill. Now science is a wonderful thing and tells us that power, which is energy use in a given time, is given by multiplying the torque (turning force of the pedals) by the rate at which they’re turning. In other words if I turn the pedals twice as quickly but use half the force the power will be the same. Does this mean that, as a cyclist, I’ll use the same energy? Well not really. It obviously takes a certain amount of energy to turn the legs around in a circle so you might think that you’ll be less tired if you pedal more slowly with more force since you’ll make less rotations and expend less energy just in moving the legs. Again this is too simple. We have different types of muscle for strength and speed. I’m sure both types of muscle are in play as we pedal along but what will change is the ratio at which they are employed. At a slow cadence it might be mainly slow twitch muscle whereas at a fast spin fast twitch will be the big contributors. What we need to do is find the correct cadence and effort for our task. Simple, except that we still need to think about speed. I might be happy to stress my leg muscles or breathing to the limit to gain the maximum speed over a ride or a part of the ride. Today I decided to try upping my seemingly slow cadence to see how it affected not so much the speed as the feel of the ride. I want to know if faster spinning will increase my breathing but save my muscles.

Riding to the trails I measured my cadence at a fairly fast rate of rotation, counting 40 rotation in 27 seconds. This equates to a rate of 88 rpm. I found the rhythm needed to pedal at around 90 rpm and measured it on the road then a flat dirt trail. I tried to keep the rate up on a fairly steep grass, rock and dirt climb but it’s far harder maintain it. My rate was dropping into the 60s but still faster than I would usually use. At the top I started to feel that my breathing was higher than normal but wasn’t feeling much in the muscles. I continued over the top of the hill and made sure I didn’t slow my pedalling. Just over the top I noticed something interesting so stopped. I was feeling a little wobbly. I’d need to drop my torque because I was tiring myself and it took a while for my breathing to calm down.

I’d spotted 2 large fly agaric mushrooms. These are what gives Father Christmas his red and white livery. They contain one of the strongest hallucinogens known. In Scandanavia reindeer eat them and get absolutely mullered. They are so stoned they apparently think they can fly. Quite why we also believe they can fly is a mystery but as long as they continue to tow Father Christmas along on Christmas Eve to deliver the presents I won’t worry too much.

Back in reality I rode along to White Coppice, staying off road and keeping those pedals spinning. I used the technical side of the Goit to Brinscall woods and a somewhat older gentleman kindly stepped aside for me so I thanked him. As I passed I noticed that he was walking with bare feet! God damn hippy. Perhaps I should have appraised him on the location of the hallucinogenic mushroom? There must have been like 50 tabs of LSD in those babies.


Up the steep woodland climb my rate was again down to around 60 rpm. I was in my lowest gear so had no option but to grind it out to the top. After a more technical trail I was breathing quickly but I honestly think that upping my cadence was saving my muscles. I turned around and had no thought about cadence whatsoever. This is where mountain biking differs from road riding. I was now about to pump endorphins around my system with a thrilling downhill. The excitement of reaching the limit on a wild trail is way better than anything you could get from a drug dealer, I’m told. I rode back over Healey Nab still trying to keep the cadence up and got home knowing I’d tested my lungs. I really don’t think I stressed my muscles as much as normal but did breath harder. Whether I would have been faster at a lower cadence is not something I know. I think on a long ride it would definitely be best to keep the torque down and cadence up to spare the legs. I need to do more research which is great because there’s nothing better than research on a bike.

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