u should be advanced before u do em. u need to have a flexible achilles and have acess to ankle weights and jumpsoles. u need to have lots of recovery time and u have to warm up for 20 mins and use deep heat and then stretch out the the achilles and calves. once u are advanced and do this properly u can gain 3 inches in a week

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Age:15 Height: 5' 10" or so. Running Vertical Jump: about 33-35 inches
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