I dont agree mate !

Dont use medicine balls for the following

1, your not in proper motion
2, Mentally you can steel yourself
3, You rarely get hit sqaure in the abs unless you're a novice .
4, you do damage to to your back ,liver ,neck and stomach region
5, medicine balls dont simulate a punch


everything about using a medicne ball goes against the better principles of boxing .

Go to a gym and you will see trainers using them on somebody crunching their abs and awaiting impact, that doesnt simulate a punch in the gut when your tired .
What it will do is send massive impact throughout your entire body and usually at the worst time when your back and neck ares arched .

Any good trainer will tell it can do all kinds of damage it wont prepare you for a good body shot delivered around the side of the ribs .

Damage to the liver is commn in boxersand that is key to how the body operates in time of stress .

Seriously lay off the Medicine balls they belong in the history books with heavy bags !