Introduction to Sports Biomechanics: Analysing Human Movement ...

Figure 2.4 Explanation of division of distance jumped into three components: TOD = take-off distance; LD = landing
distance; circle denotes position of jumper’s centre of mass.
Figure 2.5 Level 3 of long jump model – factors affecting flight distance.
QUALITATIVE ANALYSIS OF SPORTS MOVEMENTS
resistance. A quantitative analyst would probably ignore air resistance, having no easy
way of measuring it. The qualitative analyst must be careful not to be led down a ‘blind
alley’ here; air resistance could be reduced by adopting a tuck or piked position, which
would be more ‘streamlined’ (see Chapter 5) than the extended body position of the
jumper in Figure 2.4. However, although many novice long jumpers tend to pike or
tuck, such a position is detrimental to overall performance, as it encourages forward
rotation of the jumper’s body, which adversely affects the landing distance (see above).
Again, we now need to prioritise the development of level 4 of the model. Which of
the take-off parameters is most important? Most readers will know that the take-off
speed is by far the most important, as the distance jumped is roughly proportional to
the square of the take-off speed, and that the other two take-off parameters are far less
influential (see Chapter 4 for confirmation of this). Level 4 for the take-off speed is
shown in Figure 2.6(a), where the take-off speed has been divided into the run-up speed
and the speed added – or lost – on the take-off board. The first of these gives us our first
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