Is this an explanation for why I, a dedicated grinder up hills at a low cadence on my bike, am finding it ever more difficult to keep a running gait going when going uphill in fell races?
Actually, no it isn't. In my younger days, when I was rather good at running up steep hills, I was even more dedicated to grinding up hills in a high gear at a low cadence on my bike. In fact, in my teenage years, I was under the impression that the object was to stay in the highest gear possible when going up any gradient. And when I did change down to the 49-inch bottom gear on my Triumph Roadster, I could get up 1-in-8 hills. According to the principle that "What doesn't kill you, makes you stronger", this may be why I have had very few problems with my knees in all my years of fell running.