Originally Posted by
monkeydentity
is the idea of keeping a faster cadence strictly for aerobic benefit? I know that not mashing is better for the knees, but at 60 i certainly felt like my knees were safe. what's the reason for wanting a higher cadence than that? there has to be something special about it if the pros are all doing it(?)...
The pros are doing it because they can. You aren't doing it because you can't - yet.
To a very great extent, the pro and elite cyclist operates at a higher cadence because they are aerobically very fit and have lots of power. Their high cadence is a consequence of their prowess, not a cause of it.
As has been said earlier in the thread, high cadence imposes greater stress on the cardiovascular system. What isn't usually understood is that this is because pedalling at lower cadence is actually more efficient in terms of oxygen consumption. There's an energy cost to just moving your legs fast, irrespective of anything else. So of course new cyclists, or those who are unfit, find low cadences easier because that is the way to get the biggest bang for their very limited buck - that is, their limited capacity to transport oxygen and burn it in their muscles. The downside is that those muscles have to operate under a greater load for each pedal stroke. That isn't just tougher on the joints, it means that the muscle gets fatigued.
As one gets fitter one's cardiovascular system gets more efficient, one's muscles get more heavily vascularised and so one can transport and consume more oxygen. The loss of efficiency in oxygen consumed for a given power output ceases to matter so much - one has oxygen to burn, so to speak - and one is able to trade that off in return for less stress on the muscles. So, ultimately, one consumes more energy to go faster but with less fatigue and better recovery.
So, to tell a beginner to spin at 95rpm is foolish. They can't do it, they're like a demented hamster and simply exhaust themselves. But one should encourage them to use a slightly lower gear than they think they can comfortably sustain. If you're doing 60 rpm in a 50/18 gear, change down to a 50/20 and spin at 65 rpm. This relatively small change will be slightly tiring at first, but it is do-able and will both increase the intensity of your cardiovascular workout and get you used to pedalling a bit faster, with slightly less pressure on the pedals. As you get fitter you'll be able to raise your cadence by degrees - indeed you might find yourself doing so naturally - and you'll be going faster, for longer. But there are no rules about this. Don't worry if you never get to 90 or 95. If you watch videos of Bernard Hinault, who won the Tour 5 times, you'll see that he often pushed a huge gear at low cadences. He did have knee trouble, though. LOL