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The Continuous Chain Model
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| The “continuous chain” in the pole vault revisited and reinterpreted. |
| Over ten years ago Roman Botcharnikov made a brave attempt to explain the effectiveness of the Petrov/Bubka model of vaulting by developing his ‘Continuous chain’ concept. He argued that the vaulter must put a ‘continuous chain of energy’ into the pole throughout the vault. Above all the athlete must avoid passive phases where they move on the pole but do not put energy into it. Although Roman was conceptually spot on, few, if any, coaches took up his ideas. Unfortunately one or two coaches seized on the term continuous chain and promoted it as their own whole completely misunderstanding the underlying concept. This is perhaps not surprising. In the first place Roman’s innovative analysis required an intellectual understanding of this complex event and, secondly it did not provide the immediate answers pragmatic coaches are looking for to solve their day to day problems. |
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The purpose of this paper is to reinterpret and restate the principles Roman was attempting to put forward, in the hope that these crucial ideas, which do help to explain the effectiveness of the Petrov/Bubka technical model, are more widely accepted, their implications understood and their potential used to help coaching in the pole vault move forward.
I would ask readers to liken the old fashioned approach to flexible pole vaulting with a cannon. Just as a cannon puts all of its energy into the projectile in one enormous explosion, many vaulters still try to hit the pole as hard as possible at take off to create an enormous bend in the pole even before they leave the ground. All of their energy is put into the pole at take off and they then swing passively on the pole as they try to move into position to exploit the recoil. They miss the chance to put energy smoothly and continuously into the pole throughout the vault and so are limited in both the grip height and pole stiffness they can employ effectively. In fact the vaulter often puts so much strain energy into the pole, even before they leave the ground, that it begins to recoil early and the athlete is punched vertically upwards or even backwards with no chance of clearing the bar or reaching the safety of the pad. Dangerous stuff!
Now think of the Petrov/Bubka technical model as a multi stage rocket, in which each stage fires in the correct sequence to accelerate the vaulter into the space above the bar. As with the rocket, energy is put into the pole in a smooth continuous flow with each stage melding smoothly into the next until the vaulter drives off the top of the pole. Roman suggested that this should occur in an unbroken chain, but it may be easier for coaches to understand the concept if they think of four distinct phases, just like a rocket. |
| As with a Saturn rocket, the first stage is the most powerful as the vaulter hits the pole with the kinetic energy generated by the fast controlled run up and upspringing take off. Figures 1a,b, c. To ensure that no energy is lost in bending the pole before they leave the ground the ‘Petrov’ vaulter uses a ‘free’ take off. Here the vaulter concentrates on driving the pole up and towards the pit and not on bending it. This means that the athlete loses no speed and therefore no kinetic energy before they leave the ground; this not only puts immense energy into the pole in a way which causes it to begin to flex rapidly and easily, it puts the vaulter in the best possible position to fully exploit the second stage. |
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| The second phase begins immediately after the vaulter drives off the ground with a complete extension of the take off leg and ankle. This vital action ensures every last unit of energy is driven into the pole but also leaves the take off foot well behind the body with a slight flexion in at the knee. Figure 2a. This puts them into position to execute a long whipping swing of the extended body around the top hand. Figures 2b,c,d. This whip is initiated by a vicious kicking action of the lower leg, but is then continued and accelerated by the elastic contraction of pre stretched muscles from the sternum to the knee of the take off leg. |
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One only has to consider the way children can drive a swing to the horizontal to understand the potential energy input from this kicking/whipping action.
This vital phase is often neglected by coaches who do not understand the contribution it can make to energy input and who are content to see their athletes consistently take off ‘under’. Unfortunately athletes who take off ‘under’ and are ripped off the ground, will find it difficult if not impossible to exploit this second stage because they can never drive the foot back far enough after take off to set up the whipping action.
Properly executed, this stage also enables the athlete to rapidly swing up to ‘cover the pole’, Figure 2e, and so position themselves to exploit the potential of the third stage. It is here that Petrov’s genius becomes evident. While traditional approaches to technique often leave the athlete struggling to exploit the energy of recoil, Petrov devised an approach which not only put the athlete into the perfect position to exploit the recoil, but enabled them to put energy into the pole while they were doing so! |
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