Gym is the first class you'll take that doesn't start inside the main school building. The gym is to the south of the school, on the right hand side just beyond the bull statue. The class is taken by Mr. Burton.
To start the class you've got to get changed; the boys' changing rooms are down the stairs between the bleachers, and on the left. Walk into the orange circle and press 
to start the class.
There are two types of "study" in Gym - wrestling, in which you'll learn new grapple moves, and dodgeball, which increases your slingshot accuracy.
Gym 1
Wrestling versus Fatty, who never attacks you and doesn't seem to mind getting bashed up.
New Moves
- Headbutt - press
to grapple, then hold 
to nut the poor guy. - Three-hit grapple combo - press to grapple, then press three times and hold down the last one to execute a knee to the nuts.
Gym 2
Dodgeball, best out of 3, versus the preppies.
Tap to wrestle the ball away from your opponent, 
to pass, and 
to hit. Pass the ball around but try and shoot with Jimmy, he has the strongest arm.
Try and jump with 
before throwing the ball to get a more powerful shot.
Gym 3
Wrestling, same drill as last one.
New Moves
- Grapple, then press
to takedown to the ground, again to knee drop to the nuts. - Three-hit combo, , and 3 's in a row.
Gym 4
Dodgeball, same as the last one, except against the greasers. Use the same strategies as last time, and you should breeze through.
Gym 5
Dodgeball again, against the jocks. You should know what to do now.