I believe that the real power is in one's internal energy combined with the right relaxation. Many times when I make contact with my opponent it feels like my energy passes over to him, like when I hit F-16 Forrester on his guard and still knocked him down. It's like the tail of a whip, on its own it has no real weight or impact power, but when one cracks it properly and it hits you, you really feel it!! When I feel well in the ring it's like I am boiling over with energy; on the one hand I feel light as a feather and on the other hand, it feels like my punches have the power of a heavy weight.
My training routine basically consists of Kickboxing training, running and weights. Very important for me as a fighter is eating proper home made food, live seriously, get enough sleep and most of all fill myself with positive energy; stress and pressure are bad for a fighter.
 

There is nothing wrong with training hard, but many fighters over train themselves. I also train a lot, but I do so under medical surveillance. For instance, I regularly do CPK tests to check for the lactic acid levels in my body. I have seen fighters train like crazy in the gym and look washed up in the ring. This is because they over train and stop training two or three days before the fight. If your lactic acid level is too high, it takes at least 7 days to get it out of your system. Stopping your training two days before the fight is just not enough if you are over trained.
Also if they are on the edge of your weight limit, many fighters drink very little the last days in order to make the limit, then do the weight in and immediately drink a lot; this is wrong. If the weigh-in is the day before the fight there is no problem, you can slowly intake water and recover within 25 hours your fluid balance. If the weigh-in is however in the morning and the fight is the evening then you have a problem, everything you drink will just pump you up or you urinate it, the body does not recuperate.