Jim,
I'm not sure I agree that it's as simple as you have described. If a certain torque (measured in foot pounds) is required, then a longer lever ( the crank ) means that less force is required to push on the lever. But, the actual geometry of a pedeling stroke is so complex due to to all the angles involved. I'm thinking that real life experience over the years has led to the present crank arm lengths, and, it just works well to use longer cranks for those with longer or stronger legs.
For the recreational cyclist, we get to pick the gears we ride and control knee stress by picking easier gears ( or at least I do ). Again, it's not simple especially when climbing, as you may need to overstress knees once max'd out on a long climb. Years ago, the training guidelines stated to stay out of big chainrings for the first 1000 miles of the season and learn to spin.
It may be that a roadie has the advantage in controlling knee stress as, unless we climb, there are few times when the knee is overstressed. I know when I train in the winter on paved trails in a park that has many short climbs, I do beat up my knees more than on a road bike, so I think MTN bikers may have higher risk as flat terrain is not common. Perhaps, brute force is used in place of subtle technique, but, I've no experience in MTN biking. Then again, maybe I'm just trying to work harder in a shorter riding period and the knees pay the price.
But, as usual, I've been proven wrong......many times in my life.
Home
Login
Register