I've noodled on this quite a bit, and feel like there's much more to it than a blog post, but I will toss this out there in a less-than-thought-out form.
On one hand, I believe that every leader has a "terminal velocity" to their leadership capacity and abilities. In other words, we each have a speed, pace of life, maximum capacity, maximum level of influence etc. that we reach and we simply can't go any faster, do more stuff etc. Like a bowling ball falling from the sky, at some point we max out. Your "terminal velocity" may be different than mine, but we all have it....at least I tend to think that's the case.
But, on the other hand, when the power of Christ is moving in us we are capable of far more than our natural skills would ever allow. Think about Peter...certainly in the flesh, his terminal velocity was limited. He was an un-educated fisherman. Then Christ entered his life.
But we all know of Godly leaders who seem to "max out". Don't confuse "max out" with "burn out". I'm talking about Godly men and women who are spiritually and emotionally fresh, with tons of vision and ideas etc. that simply reach a limit to what they can accomplish....their leadership and ministry terminal velocity can't do more.
But, I can do ALL things through Christ, right?