I’ve been searching through my ‘archives’ and came upon an article written back in 1978 by Dursenev and Raevsky. The article is entitled ‘Strength Training for Jumpers’.
I’ve condensed it and attempted to glean for you the most important points. Many of the recent strength articles link sports performances with effective work ‘only in the concentric action – muscle shortening‘. Hence the athlete’s maximum strength is judged by the greatest strength that his/her neuro-muscular system can develop during a maximum voluntary contraction.
Dursenev & Raevski state that all strength training regimes develop strength using concentric movement patterns.
Recent studies have shown that in JUMPING EVENTS one’s results are limited not by the maximum strength manifested by the take-off leg extensors and spinal extensors, but by the strength which these muscles demonstrate during their stretching, during their work in the ECCENTRIC [yielding] action.
All this means is that when the take-off leg strikes the board at high speeds all the leg muscles are lengthening so they must exhibit great levels of relevant and specific strength in this lengthening process in order to be able to have control at touchdown/take-off.
Jumpers must execute such work under the influence of a kinetic energy reserve [acquired during the approach run] at the start of the take-off [TOUCHDOWN], in the so called AMORTIZATION [shock absorbing moment] phase.
For a jumper who is approaching the take-off board at a very high speed and be expected to transfer that horizontal velocity to a vertical impulse in the shortest possible time this has great significance.
The forces during this phase are significantly greater than in the push-off phase. On the final stride to the board the moment of impact [take-off foot on to board in the dorsi-flexed position which is attained by bringing the toes into the shin] is an area which must be given great attention by the coach -EVEN FROM A VERY EARLY AGE. There is no need to explain in great technical detail to a novice or young jumper in the early stages of learning these bio-mechanical implications, but just impress upon them that this MUST happen to effect a decent touchdown to take-off.
The strength needed most by a jumper is not for extension of the push-off leg but to PREVENT excessive flexion during amortization, helping to change the direction of the speed acquired during the approach run. If excess flexion of the support leg in this phase is prevented, then the final phase of the take-off…the so called push-off is executed successfully.
The rest of the article goes on to rationalise that jumpers SHOULD develop strength through eccentric means rather than concentric means. That is why Plyometrics and Complex Training are of such value to a jumper.
This specific type of strength programme develops the elastic, explosive and reactive strength that all jumpers require.
This attempt to get rid of unwanted flexion at touchdown in the amortization phase [yielding] phase is crucial to a long jumper.
THE BOTTOM LINE!!!!
Encourage your young jumper to keep his/her take-off leg LONG AND FIRM at the moment of touchdown, and attempting to place a full foot in the dorsi-flexed position on to the board to effect the ankle sweep back.
Speak with you all soon,