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| HJ - Height, Rotation, Angle, Back Arch, and Clearance http://masterstrack.com/forums/viewtopic.php?f=5&t=1567 |
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| Author: | glenstone [ Mon Mar 07, 2011 10:47 am ] |
| Post subject: | HJ - Height, Rotation, Angle, Back Arch, and Clearance |
I recently did a computer study of how the following things are related in the high jump: - the amount you lift your center of mass in a jump, - your rotation about the bar, - the angle your flight path makes with the plane of the bar, - your back arch during the flight, - and your bar clearance. What I found is the following: - There is a back (body) arch that can be maintained throughout the jump that yields approximately equal clearance throughout the flight. - Changing the angle that your flight path makes with the plane of the bar has very little effect on the constant body arch required for equal clearance throughout the flight. - Changing the lift (how much you lift your center of mass from the instant of lift-off to the peak of your flight) greatly influences the back (body) arch required for efficient, equal clearance throughout the flight. If the lift is small, both the required lateral rotation rate at takeoff and the required back (body) arch are great. You must rotate quickly and arch a lot. However, if the lift is large, both the required lateral rotation rate at takeoff and the required back (body) arch are small. You don't have to rotate very fast nor do you have to arch much. - The rotation rate for efficient clearance is such that you rotate through 90 degrees laterally from liftoff to the peak of the flight. Thus, the body is horizontal at the peak of the flight. Glen Stone |
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| Author: | weia [ Mon Mar 21, 2011 4:17 am ] |
| Post subject: | Re: HJ - Height, Rotation, Angle, Back Arch, and Clearance |
You are very right about that rotation rate. The pity is that we jump lower from age group to age group, but our bodies do not shrink in the same manner, so we have to have the same amount of rotation in a shorter time... |
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