Introduction to Sports Biomechanics: Analysing Human Movement ...

INTRODUCTION TO SPORTS BIOMECHANICS
the horizontal and vertical velocities. On the board, a long jumper needs to generate
vertical velocity while minimising the loss of horizontal velocity from the run-up. For
the horizontal component, there tends to be an initial ‘braking’ force followed by an
accelerating force. We also need these two velocity components to develop our model
of take-off angle, the tangent of which, from Figure 2.8, is simply the vertical velocity
at take-off divided by the horizontal velocity at take-off. However, with the modified
approach, we do not need to develop a separate branch of our long jump model for
take-off angle, as we have now effectively replaced level 3 of the model for flight
distance, in Figure 2.5, by Figure 2.9.
Figure 2.9 Revised long jump model for flight distance.
We now, therefore, replace the branch for take-off speed (level 3) in our long jump
model (Figure 2.6) by separate branches for the take-off horizontal and vertical velocities.
We then develop levels 4 down of our model for each of these branches by using
relationships for the two components of the take-off velocity that are equivalent to the
ones we developed above for take-off speed; this gives us Figures 2.10 and 2.11.
Figure 2.10 Factors affecting take-off horizontal velocity.
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