This week I've just started lifting, if you can call it that. Squats, Deadlifts, and Single Leg Press. 3x4 and 3x3 the next, for 3x a week. For weight conscious climbers that seems to be the best plan; building strength without mass. Right now I'm probably doing 60% of1rm, and I'll build that up and be there for a few weeks, take a few weeks off and start again at 60%.
I don't expect this to make me a sprinter, just make my body a bit stronger and more efficient. Some studies have shown this works, we'll see how it goes.