When you guys pull your arms back to get ready to jump, do your arms typically stay straight, or do they bend? I've looking at a lot of video's on youtube lately and it seems like whoever keeps their arms straight jumps higher. Does keeping your arms straight have any correlation into jumping higher?

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Age: 21
Height: 5’11 and ¾’s
Reach: 7’8
Current Standing Vert: 28 – 30inches (touch 10-10’2)
Current Running Vert: 34 inches (touch 10’4)
Goal Standing Vert: 33 – 36 inches (touch 10’3-5)
Goal Running Vert: 37 inches by 3/29/08 and 40 and up by 4/29/08
Weight: 182lbs (my goal is to be 165 – 170)
Bench: 210lbs (goal is to bench 225)
Squat: 315lbs (goal is to squat around 365)
Sumo Deadlift: 315lbs (goal is to deadlift around 365)