In Fighter's Mind/Fighter's Body, I present several factors involved in power generation. Many people mistakenly assume power is the same as strength, but strength is just one aspect. Good strength exercises are push-ups (the book presents many variations to increase resistance), core work such as medicine ball passes, and squats.

The other aspects of punching power are acceleration (speed), alignment (coordination), acuity (reflexes), and technique.

A fired bullet gets its power from speed, which is a neuromuscular activity. You can train specific actions, such as speed drills specifically for punching, but since speed is a neurological activity, you can also benefit from non-sport-specific exercises such as sprinting. Any activity where you're moving so fast that you need to pay close attention to your body movement will help improve neuromuscular firing.

Strength and speed training prepare your neuromuscular system and joints for plyometric training, which trains your body to employ strength explosively. Three of the best plyometric exercises for punching are clap push-ups, kip-ups, and alternating lunge jumps. Kip-ups train your core to tense explosively to transfer your whole body behind the punch, and the lunge jumps train you to drive into the punch.

Alignment is the ability to put your whole body behind the punch. This is similar to the power of a locomotive. A train moving at just 5 MPH  will kill you if you get in the way, because it has so much mass. The more of your body you can put behind your punch, the more power you'll deliver. Some good exercises for punching coordination are cable presses and wrestling shoots under a heavy hanging bag.

So much of knockout power is in the timing. Watch any boxing knockout. The boxer is always moving into the punch when he gets knocked out. A powerful puncher knows how to time his punch so the target is moving toward his fist, like a head-on car crash. Working the heavy bag will help, as will punching a wonderball, and also practicing the eye focus drills.

Finally, work with a good coach to perfect your punching technique. That's what ties all the other aspects together correctly.

In summary, some good exercises are push-ups or cable presses, medicine ball passes, and squats. Once you feel ready, incorporate clap push-ups, kips, and alternating lunge jumps. Also work the heavy bag and punch a wonderball.

One other thing: make sure to work all the aspects of endurance, so you can keep punching hard for longer. Hope you find this information helpful!