We made a homemade diy vertimax for $50. Check out the video for more details. The homemade vertimax can be used for basketball strength training and for jumping.
When your son is using that vertimax, how does it keep it down on the floor, how much does it weigh? I know you said you bought the cheapest wood you found but there is bound to be a weight issue along side the resistance bands pulling the board up with it
