There are three very important reasons to use body shots. The first is taking away your opponents’ legs, or slow him down. Your opponent will be covering his face, body shots will surprise them and get them off balance, and this takes away their legs. Once you have taken away their legs, you have them in a position to knock them out or at least gain points with the judges.
The next reason to use this type of punch is so your opponent brings his hands down to block his body thereby leaving the head wide open for a knockout. After a proper body shot your opponent will lower their hands, with the perfect head shot you can score a knock out. You would be using this to set up the knockout punch, the ultimate in boxing. You can use hooks or uppercuts all in combination with each other. When the uppercut lands in just the perfect spot, the solarplexis, this will knock the wind right out of your opponent leaving them wide open for the knockout to the head.
The last reason is just absolute punishment that the body takes which then breaks the will of your opponent. How does this break down your opponent? They are confused; they don’t know whether to cover their head or their body, they are worn out from the constant defense. Punches to the body thrown at close range are much safer than the long distance body shots. Long distance shots leaves you wide open to be counter punched. You can use body shots at close range. When you are in the pocket, your punches need to be short and precise with a lot of power behind them. The key to this is bending your knees while coming forward. By doing this you are dominating your opponent, again scoring points with the judges. Not all fights end with a knockout, but you will definitely gain confidence with the judge’s decisions. Overall, you just have to be relentless as an amateur and a professional fighter.