Researchers have focused on what happens at take-off, as well as the penultimate step, and how this affects distance achieved in the long jump.
Specifically, the team analysed the male and female long jump finalists at the 2008 World Indoor Championships in Valencia.
The jumpers had their positioning and movements through take-off analysed by high-speed cameras.
Analysis was made of the time the jumpers spent on the board and the way their muscles and, more specifically, their muscular actions worked to transfer them into the jump.
When a jumper’s leg hits the board a “stretch-reflex” occurs. The muscles of the ankles, knees and hips go on stretch (eccentric muscular action), there’s then a minute time delay (amoritization phase) before the jumper’s muscles ping back from the stretch to propel them into the air (concentric muscular action). The researchers were able to analyse what they termed the “compression” phase (eccentric action) and the “extension” phase (concentric action).
In the men’s final, for example, it was discovered that the compression phase lasted between 40ms-56ms and the extension phase 72ms-80ms.
The total take-off time for all male jumpers averaged 122ms and for women 117ms. When considered collectively the male jumpers used 37% of their total take-off time eccentrically and 63% concentrically.
The times for the eccentric and concentric phases for the women were collectively lower and interestingly it was discovered that the women spent more time absorbing the contact on the board compared to men (the eccentric phase).
All jumpers lose speed at take-off (the research identified a 10.3% loss for the women and 8.7% for men) – minimising loss of speed is crucial to maximising distance jumped.
The researchers write: “The compression phase is decisive for achieving the required braking so that the horizontal velocity built up in the approach run can be transformed into vertical impulse. In this phase the jumper accumulates elastic energy; the fact that it is so short proves the jumpers’ extraordinary ability to complete such transformation.”
The researchers didn’t provide any direct “do this or thats” which would place their findings into a practical application for coaches. However, it could be recommended that:
1. Long jumpers should regularly do full approach work, thus training at the velocities needed to develop the timing required to jump from a full run-up (too much short approach jumping will have less positive transference into full approach jumping). Note: full jumps do not need to be made all the time as take-offs only from full approaches – without a complete jump – will be a close match.
2. Eccentric capacity needs to be developed by specific exercises (for example, drop and hold depth jumps). Females may benefit from added eccentric work – although this will be athlete-specific.
3. A great deal of work needs to be done on developing leg stiffness and an enhanced stretch/reflex via specific exercises and throughout the training plan by use of plyometric exercises.
4. The pattern and positioning of the take-off steps needs to be constantly worked on.
Source: John Shepherd