So as you all know I'm big on homemade equipment and recently I was interested in making a tornado ball for rotational strength. I saw Matthew Palfrey from sandbag fitness uses them sometimes for his workouts. He suggested between 5kg and 8kg depending on your current strength level. So I made myself another medicine ball (seen here) and picked up a cheap tow rope from a hardware store. I also found a guild to building the ball on Ross Enamait's website.
First step is to tie your rope around the ball as tight as you can (I wanted two handles but just one is fine.), then duct tape the hell out of it. You really don’t want the ball coming out as you swing it around your head, it will do a lot of damage to people (yourself included) or property. I ran out of duct tape otherwise I would have kept going. In his guide Ross used a basketball net and load of duct tape, but I think the tow rope I used for mine (with some more tape added) will work great.
And that all it takes, your done in no time. Since this ball is not totally full I think it could take being used for slams, using it like you would a sledgehammer but I don’t know how long it would last - I think it would need more padding.
Now all you need to do is start swinging. Feet shoulder width apart (don’t let it pull you over), back straight and tall, shoulders back. Take it easy, start by going slow and chocking up the rope. As you get used to using the tornado ball (or if you find its getting a bit easy for you) try lowering your grip on the rope and/or swinging faster.