Too add on from the good stuff from above. I know a jumper at 53 feet. He only half squats 315 lbs at 5 sets of 5 for strength. The catch is like Banks he bounds a lot for his strength. Also he is incredibly flexible in the hip region. He could do the splits both ways. Flexibility of the hips and low back is your best bet for a big wopping jump. When he jumped, he was able to produce more force and get full extension off of each bound by being that flexible ( so he says). So maybe thinking about hip extension and flexibility is the problem and not strength. I have squatted 385 and it does absolutley nothing, except prevent injury.
