At the beginning of the winter i practiced my handles like 1,5 - 2,5 hours and it helped a lot. Before winter i could'nt dribble behind my back and do between the legs without looking the ball, but now i can do all drills i know with 1 and 2 balls without looking. I think you should do every drill about 1 or 2 minutes.

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Age - 13
Height - 5.6
Vertical jump - 24"
Program - VJB Beginner plyos, VJB Bodyweight.
Goal - Vertical around 30"