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Running jump

  1. Jun 18, 2009 #1

    daniel_i_l

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    Why does running before jumping help you jump higher? The only explanation I could think of was that right before the jump you redirect your speed into the ground and compress your bones. This compression gets translated into an upward thrust when they expand again. What do you think?
    Thanks
     
  2. jcsd
  3. Jun 18, 2009 #2
    A nice question. And I think your explanation is right. Just before the jump, the jumper often tilts backward a bit doesn't he?
     
  4. Jun 18, 2009 #3
    I could think like running gives forward momentum ,and gives inertia of motion to have higher jump
    Otherwise if we directly jump, inertia of rest doesnot contribute for thehigher jump
     
  5. Jun 18, 2009 #4
    Is this an observe or what? I suppose not agree with you. If you run, only help to jump (horizontal) further. For example triple jumpers run to jump further. But high jumpers run to pass over the stick. Sorry for poor language.
     
  6. Jun 18, 2009 #5
    I doubt too that running makes you jump higher. The only reason I think high-jumpers run is because their jumping technique is better that way. In that sense, running does help them, but it is not the speed of running that helps them. In fact, if it would be, then why do they run so slow? They could run at least twice as fast. If that would give them more height, they would. But they don't, so I don't think the speed of running actually helps you jump higher.
     
  7. Jun 18, 2009 #6
    Suppose you wanted to jump up (not clear) 2 meters, and also go forward 2 meters. Using h = 0.5 gt2, you will be in the air for 0.64 sec. So your forward velocity should be 2 meters/0.64 sec = 3.1 meters per sec. In your center of mass system, you are jumping up vertically.
     
    Last edited: Jun 18, 2009
  8. Jun 18, 2009 #7
    I do not think anyone can jump as high (as when he run) if he stand still and jump. The momentum forward can be redirected upward and the whole body is somewhat similar to a spring.
     
  9. Jun 18, 2009 #8
    To jump the furthest distance, jumping from a solid surface, ideally you would convert your horizontal momentum to be directed upwards, ~45 degrees.

    The energy storage in elasticity is from tendons, not bones, when this momentum is redirected. It's not an ideal storage medium, so there is some happy medium between zero and 45 degrees.
     
  10. Jun 19, 2009 #9

    Danger

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    Nicely said, Phrak. If you're running hard enough to compress bone, you're not going to be moving much longer. Forward momentum (inertia) gets translated into vertical/diagonal movement during a high jump or other similar endeavour. Think of hurdles, for instance. Nobody that I know of could hop over one from a standing start.
     
  11. Jun 19, 2009 #10
    Thanks Danger, though I'm strictly an armchair hurdle jumper.
     
  12. Jun 19, 2009 #11

    Danger

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    I didn't mean to imply that I'm athletic myself. I couldn't jump a hurdle if I was wearing a jetpack.
     
  13. Jun 19, 2009 #12

    LURCH

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    Better yet, think o fthe pole-vault. Forward momentum is converted to vertical lift by placing a pole in front of the forward-moving athlete. In high-jump, the "pole" is the jumper's lead leg mostly, then by the second leg as he brings it up alongside.
     
  14. Jun 19, 2009 #13
    Do you truly jump higher when running, though? I mean, obviously you'll have trouble jumping hurdles from a stand-still, but that's because you can't just jump straight up. However, say you were to catch something high up in the air, wouldn't you be better served standing still and jumping rather than running and jumping? I'd think you'd be able to direct more momentum upwards jumping from a standing position since you have more time to jump than if you're rushing forward at a high speed.
     
  15. Jun 19, 2009 #14

    LURCH

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    Last edited by a moderator: Apr 24, 2017
  16. Jun 19, 2009 #15
    Yeah you jump higher when running. That's why high jumpers run before they jump. They couldn't jump 7 feet in the air off of one foot without the running start.

    I can touch a 10 foot high basketball goal with a running jump off of one foot, but I can't even touch my 8 foot tall ceiling off of a standing one foot jump.
    That's a good point.

    I also noticed that when jumping off two feet, I get the best height when I do a step forward and jump. If I just jumped straight up from a standing position, I don't get as high. That initial step forward helps me jump higher. Why, I have no idea.
     
  17. Jun 19, 2009 #16
    But, as someone asked before, why don't they run faster? Could it be because, they need to turn around and push with both the legs for maximum power?

    That explains why in pole-vault, they run with their maximum speed. In pole vault, not much leg power needed, and they get time to turn around in the air.
     
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