I have always been strong in the gym, but my weight training focus for the past three years has been to imitate that V02 max (or just under) grind that really takes a lot out of the legs and fatigues the muscles. I have found tremendous benefit to doing these mush longer sets at very light weights and while I personally believe that weights do not help threshold at all (with many studies backing that up), I do believe that it can delay muscular fatigue associated with low cadence and maximum efforts along with the very real and documented benefit of increases in contractile power due to neural synapse proliferation.

All of that to say that my top end and muscular endurance are much better and (if only anecdotally) I attribute it to the time in the gym.