What Irulan said.

Sometimes you just have to power over an obstacle. No easy spinning with a high cadence over everything. Being a veteran of sore knees (chondromalacia), this year's TE Girls' Hill Climbing Program put me in the best shape ever for mtbiking.

Seems like I built a lot of strength by climbing hills on the road that translated into happier knees on the trail. Spinning only early in the season. You could lift weight to get some strength benefits also but I'm not the one to ask. I hate weight lifting.