So I haven't climbed routes since last September, when I went deep-water soloing in Mallorca. Yet here in South Dakota I'm finding that I'm able to give pretty good flash burns on 5.13, and I'm sending .13+ in a couple tries.
Soft grades? Not quite.
Is it possible that you dont have to climb very many routes in order to be a good route climber? Well that's kind of what I'm thinking now. Today I did several hard routes, with sustained sections of hard climbing. It wasn't 'bouldering on a rope', it was good, long, overhanging sport routes. Full pitches, overhanging about 20 degrees.
The only endurance training I have done since Mallorca is Dave Wahl's circuit program, the 'hour of power', which doesn't exactly simulate route climbing, but in terms of the overall work output involved in completing the hour of power workout, most hard redpoints are not too different. I honestly think that if you combine a circuit training program for overall fitness (emphasizing power-based activities with little or no rest between sets) with a basic program of grip strength training, such as campusing or 4x4 bouldering you can pretty much show up at any crag and expect to give any 5.13 in the house a pretty good run for its money.
The really handy part about training in a no-rest circuit is that it trains you to be able to fully recover in a very short amount of time. It's not exactly cheating, but certainly feels weired to be topping out 80-foot, sustained 5.13's without any route training at all in the last 18 months or so.