Yes, it must be so. Endurance and limit strength cannot be the same thing. What I think is going on is this: Higher limit strength makes lighter weight bearing "easier" so in a sense limit strength training does grant you what appears to be more "endurance" but is actually just more limit strength making the lighter stuff not bother you. Now, training more endurance at or near the limit would seem smart for expanding endurance strength without having to do limitless reps. Thus, the Grease the Groove method for example, where you keep doing deadlifts or other heavy grinds all day long with long rests in between. Alternately, doing medium weight exercises for medium-high reps, like the swings in S&S. Clearly "strength endurance" is a "thing" separate from limit strength. I can certainly NOT do 1500 pushups a day in any reasonable amount of time - I'll get too sore too fast. Now, I have to say that my higher limit strength is making it appear that I have also acquired much higher endurance strength on the mats at judo, but I'm assuming that this is a mirage. I'm still puzzled is my conclusion here.