As you approach extreme levels of physical exertion your body will naturally send a sensation of discomfort to your brain in an effort to convince you to slow down. Your body is geared towards homeostasis and prefers to stay within the parameters of moderate exertion. If you become anxious and reflexively pull back every time you experience the pain of fatigue, you will never actualize your potential as a fighter. Understand that your body's capacity is always greater than your mind is initially willing to concede.

Take this example. Many years ago I read an article in a powerlifting magazine extolling the benefits of a weight training routine centered around a twenty-repetition set of squats. The author suggested loading the bar with a weight that would normally be a challenge for ten reps, then squat it twenty times. The first time I read this idea I naturally resisted accepting it, thinking "if I can only squat a given weight ten times, how can I expect to squat the same weight for twenty repetitions?" In the end, though, I decided to suspend logic and commit myself to this twenty-rep principle. Here's what happened:

I loaded the bar with 455 pounds, a weight that was typically a challenge for me to complete ten repetitions. Before taking the bar onto my shoulders I resolved I would perform twenty reps, fixing that goal in my mind. I grasped the bar, touched my forehead to the center knurling, took a deep breath, positioned myself under bar, then lifted it from the rack. Absolutely focused on the destination of twenty I completed the first ten deep squats rather mechanically without any real strain. My legs and back still feeling strong, I remained resolute as I entered uncharted territory, methodically completing another four repetitions before I began to feel fatigue. The next three reps required great concentration. I took them one at a time, reaffirming my resolve for the next squat at the completion of the previous one. After the seventeenth rep my hands were numb and my thighs began to shake. I was too close, however, and quitting was not even a remote consideration. I entered another realm, one I've since revisited many times in training and competition. I let go and simply allowed myself to be pulled towards my goal. Not only did I accept the pain of fatigue, with something akin to rapture, I thrust myself into it…18…19… then 20!

The body itself may require only a few of months of hard training to get fit. The rest of the time you're building your spirit- your guts- so that they'll work for you in a fight without your thinking about it.