-
Step 1
Cut a basketball. You can use basically any basketball to make your medicine ball. The only relevant difference is the size of the basketball. Take a sharp knife and make a small slit in the side of the ball. Keep the slit as small as possible, just wide enough to stuff the spout of a funnel into it.
-
Step 2
Choose a filler. You can use any kind of grainy substance to fill the ball. Sand, rice and even gravel are good options. The difference between the substances is essentially weight, with gravel being the heaviest and rice the lightest of these three choices.
-
Step 3
Fill the ball. Stick the funnel into the ball. If there is too much resistance let out a small amount of air by holding the slit open. Funnel your filler into the ball, stopping occasionally to shake the ball so the filler settles to the bottom of the ball. Continue to fill until the ball is almost completely full.
-
Step 4
Seal the slit. Rubber sealer or super glue are good adhesives to seal the the slit with. Put enough glue over the slit to seal it and then press the slit together until the glue sets. To reinforce the glue you can put another coat on the outside. Then, slap a rectangle of duct tape over the sealed hole just to give it a bit more reinforcement.
-
Step 5
Cover the ball in duct tape. If you plan on slamming the medicine ball against the ground then you should consider wrapping the whole ball in duct tape. Begin by wrapping the tape around the sealed slit and then continue until you've covered the rest of the ball.
