Lesson
Angular Kinetics - Sports Applications for Angular Impulse - continued
During AERIAL SKILLS, ANGULAR MOMENTUM required for total-body rotation
comes MAINLY from ANGULAR IMPULSE created by the REACTION FORCE of the
SUPPORT SURFACE DURING TAKEOFF.
Eg. In a BACKWARD DIVE from a diving platform, The diver extends the hips, knees
and ankles and at the same time swings the arms backwards. The CG of the diver thus
gets positioned posterior to the vertical component of the platform’s reaction force.
This position then creates most of the backward angular momentum (via angular
torque) generated.
If, in addition, the diver places his feet further back from the tip, during takeoff from
diving board, the fulcrum is positioned further away. The board then tips downwards
More, which allows the diver more time in contact with the board to generate greater
angular momentum and thus more vertical velocity at the start of takeoff.
For both platform and spring dives, the rotation of the arms at takeoff contributes more
than any other segment, to angular momentum. When the arms are extended, the MoI
and thus the angular momentum increase.