I know this thread is kind of old, but I thought this book might shed some light on your experience: Slow Burn
, by Frederick Hahn.
Here's the theory: (I lost my copy of the book, so I'm citing this from memory; sorry if there are any inaccuracies.) Explosive strength comes from your fast twitch muscles. Unfortunately, your fast twitch muscles are also the hardest muscles to work. Whenever you begin to put strain on your body, it will first sacrifice the slow twitch muscles, move on to the medium twitch muscles, and only as a last resort does it use the fast twitch muscles.
Hahn believes that the best way to work your fast twitch muscles is to use an intense load and very slow movements so as to completely eliminate momentum. This puts the entire load on your muscles, bringing them to exhaustion faster; it also has the added benefit that it protects your joints and ligaments. His regimen advocates the heaviest weight you can bear while maintaining good form, no more than 6-8 reps, and v-e-e-e-ry slow movements (10 seconds up, 10 seconds down ... per rep!).
Anyway, I did Slow Burn for a while, so I'm very familiar with the feeling of muscular exhaustion. It's an odd one -- nothing hurts, but when you go to do something, your muscles just give out from under you (and the next day, you're sore as hell). I don't pretend to know anything about Crossfit, but I've been doing yoga for several months now, and I bring my muscles to exhaustion during every C2 class ... I often have trouble walking out of the studio. :)
Anyway, I find the Slow Burn philosophy a useful one to keep in mind, since almost any activity can be made more or less isometric and involve more or less momentum.
Interesting thread, by the way! Thanks for posting.