Resolve a friendly dispute.

[pembrokian]

Can the great and the good of this most august body resolve a friendly dispute between two javelin coaches ?

One believes that, for a right-handed thrower, the blocking left leg should be planted upon the impulse locked out and dead straight; the other believes it should be slightly bent to absorb some of the shock.

What are your thoughts on the matter ?

[wilow412]

I personally believe that you should plant the left leg with a slightly bent left leg to take away a lot of the pressure and to protect the joints but then to lock it as you ramp over the top of the left.
Just my opinion

[mike]

Plant it athletically straight!
Not forced straight, but certainly not bent.

[wilow412]

When I said bent I don't literally mean bent.I mean not locked out but so the knee is soft if you know what I mean..
My wording is no good I know

[robyn2012]

Nov 29, 2008 8:28:41 GMT 1 wilow412 said:

I personally believe that you should plant the left leg with a slightly bent left leg to take away a lot of the pressure and to protect the joints but then to lock it as you ramp over the top of the left.
Just my opinion

I agree with what you saying and its something I try to imply when I throw. When I throw I try to land with the left leg slighly bent and then straighten it or as you put it "ramp off". I know that it takes alot of time to try and perfect this because it is so easy to collapse, however, i'm working with it and I prefer that way of planting then trying to plant with a straight left leg.

[ironbrew]

In NSA by the IAAF 1996 Model technique analysis sheets Part X The Javelin throw by Gunther Tidow he wrote regarding the bracing stride "The build up of the bow of tension begins a ssoon as the thrower plants the foot of the bracing leg and it can be properly developed only if the bracing leg is as straight as possible and is grounded heel firstand at some considerable distance in front of the trunk.Since the whole system is moving forward with a velocity of up to 7m/sec when the heel spikes make ground contact, it is obvious that a high mechanical load is placed on the bracing leg. The less the bracing leg yields at the knee joint the more effective is the braking action. Many authors, suggest that the knee angle should never be less than 159 degrees (cf, Menzel 1990 and others). Theoretically a completely straight bracing leg would be ideal, since there would be a complete transference of momenttum to the upper and other parts of the body. A few top athletes have achieved this extreme to some extent(e.g. Wolferman). However, the load on the knee joint then becomes so great that there is risk of injury. Consequently, it is recomended that the bracing leg should be completely or almost completely extended prior to the moment of ground contact and then it is allowed to bend slightley "with control" and again straighten completely during the phase "from striking position to delivery" end quote. There is a lot more to the article if you look at some of the bio mechs anaysis Zelezny 92.50 throw (22/6/1996) knee angle on contact 183 degree minimum angle on pull 183 and at release 195 (ouch) Backley 85.20 (8/8/1994) on landing to 181, 182 and 187at release, Raty 87.68 (22/7/1995) 183, 190, 202 (big ouch) this is from some Finnish data. I think if you look at Thorkildson and Pitkamacki the results would be very similar in my opinion. So I would say that willow you are both on the right lines but to achieve what the top guy and gals are during requires tremendus physical ability that comes with time and correct training.
May all your throws be long uns

[carrie]

I can speak from experience here. A braced left leg that acts like a pivot is not the way to go and can seriously damage your throwing career! All it takes is for that stride to be shortened when you have sped down the runway and you can jar your back badly enough to jam vertebrae together and/or squash a disc. This injury basically ended my career in its peak stage as once it has happened, it will keep on recurring again and again.
A soft knee with legs that have the rebound strength not to collapse but to drive up into the throw will protect both knee joints and the lower back and spine.
I cringe whenever I hear other coaches advising a braced leg and I wish I hadn't altered my technique as per my second coach's advice. After having got over 50m, I always felt I had unfinished business! I wouldn't wish that on anyone else.

[sam]

a stiff left leg send the energy stright up the leg and get's absorbed by the hip/lower bacl.. a bent leg will mean that the energy get's trapped int he ankle, knee or just allthe muscles in the blocking leg. it will lead to twisting of the knee, turning of the ankle or just general colapse.


STRAIGHT IS BEST

[carrie]

Do you mean Straight or Braced, Sam? You can have a straight leg with give in the knee to soak up impact - thats what I mean as soft. But if you mean braced then I really, really disagree. There are natural shock absorbers in the knee. But if you don't use them, you are sending the unspent forces up the back and into the spinal column. If it doesn't hurt immediately, you can be sure of storing up trouble in the future. (Please trust me on that one at least)
Please look at the videos on YouTube of Fatima's world record, Tessa's winning throw at the Olympics and Spotakova's 69.15m in Spain early this season. Not a braced plant leg in sight - just some well conditioned and strong athletes driving up into the throw.
You wouldn't ask an athlete jumping down from a box or over a hurdle in a bounding session to land with braced legs. Think about it...

[Administrator]

I'd say that the answer will be slightly different for everbody. For instance Carrie says that a braced left is not the way to go as it can hurt you but in my case, throwing with a bent knee hurt me and put me in hospital 7 times. If you have a weakness in your back a braced left will hurt you. If you have a weakness in your knee, bend in the leg will hurt you.

I personally believe the leg should be as straight as possible without causing any discomfort or restriction in movement. That will mean that it is not locked out but most likely very close to straight which typically turns into straight as you rise over the left.

I'll try and find some images as examples.

[matti]

jan zelezny always threw with a straight left leg. so does andreas thorkildsen on his good throws and tero.
i dont know anyone who throws further with a bent left leg!!

[Administrator]

well thats true Matti - look to the best and see what they do. At times Zelezny's leg appears to hyperextend (I'm sure it just looked that way!) - that said these guys are physical beasts so what is possible for them may not be possible for us.

[slinger]

ironbrew's post is very good, well done for posting some proper conclusions from bio-mech studdies, i have that article and it's very good.

re - jan zelezny, indeed he does maintain a straight blocking side leg [his left] for his comp throws, reasons have been said.

apparently on his WR his left leg actually is never less than straight, i'm sure but don't quote me but the minimum angle measured between ankle, knee and hip is 182 degrees ie more straight than straight!!! ;D

[sam]

all the energy generated on the run needs to be transfered up through the body and into the javelin. If you have a slightly soft block your leg will absorb some of the energy. If you hit a straight hard block the energy transfers up throught the body into the javelin..

[dobster]

What is your view on what wilf says

A slightly more scientific approach to javelin throwing

Wilf.Paish M.B.E.

I intended to write this article some two Olympiads ago, but time and ill- health encouraged me to direct my energy towards directly helping young throwers and novice coaches to gain a greater expertise in this classic of the field events. About a decade ago, a group of coaches, mainly emanating from the U.K. insisted that the front leg, during delivery, must remain rigid. They were influenced by a relatively inexperienced biomechanist, who in turn was influenced by a relatively nebulous property of Physics, known as a “Hinged Moment” principle. Researching most of the standard texts on Physics, I cannot find any scientifically based definition of the phenomenon. I have reference to it in a small pamphlet, now very dated, in its evidence relating to javelin throwing. We all know that if we try to alight from a moving vehicle, with our feet stationary, the momentum will be transferred to the body as a whole, with the extremity ( head) experiencing a greater acceleration. Thus, scientists applied this principle to javelin throwing, stop the bottom half of the body by using a braced front leg and the upper body (arm/shoulder) will accelerate, giving the javelin a greater speed of release.

Having viewed most of our Olympians, in action, none use a firmly braced front leg. Indeed, it is my belief, that to make full use of the aerodynamic properties of the javelin, the front leg must be used as a ramp. If braced firmly, it will slow the body at a most critical time; it will promote rotation about the horizontal (transverse) axis, in the frontal plane, causing the body to “pike”. This will in effect cause the javelin to follow a simple parabolic flight path, when what is required is an extended parabola. It is a wonderful sight to see a javelin launched, like an aircraft taking –off, it gaining lift from its flight properties. Should one rely solely upon Newtonian principles, by ramping the front leg, one can increase the range of action, thus the value of work/impulse, by a significant amount, in turn contributing to a greater speed of release.

Rather, I would prefer to encourage athletes/coaches to view the event as one where the significant speed of release, is gained from rotation, about the long vertical axis, in the transverse plane. The body taking full advantage of a clever series of short, speed effective levers that contributes to the whole. For the remainder of this article my reference is the more common right handed thrower. This “clever” lever system, coming into release, starts with the right heel turning out (anti- clockwise) with its pivot about the toes of the right foot. This is followed in turn by a speed effective lever of the right knee rotating about the pivotal points of the femur/tibia/fibula. Again in turn the hip pivoting about the spine/femur, thence the shoulder in liaison with the spine and eventually the elbow and hand rotating about their respective pivots. These are all speed effective levers that produce “torque” and thus the characteristics of the “bowed” position. The left side remains a firm, but not braced, to provide an axis about which the rotation can function. My simple words of advice to the thrower, at this stage of the action is to keep the chest square and going “up” after the javelin. If the levers are used correctly the athletes should be able to “chase the javelin out”, thus needing a controlled recovery to comply with the rules of the event. At this stage of the proceedings, it is important that the left shoulder does not drop, nor rotate backwards, beyond its frontal plane and vertical axis, producing negative acceleration and detracting from the speed of the right shoulder.

The situation demands a fine eye from the coach, a kinaesthetic awareness from the athlete, and a belief in the fact that the speed of the arm is all important. Look carefully at what the Olympians do. Their efforts are not dictated by any laws of physics, but rather by the anatomical constraints of the levers of the body, driven by its muscles, and what it can accommodate in the pursuit of a greater arm speed. It will certainly hurt to a degree, thus the event is not one for the feint hearted. Thus, all throwers will not have an identical technique- the smaller thrower, with restricted lever potential; will have a slightly different technique from the taller thrower. This is the beauty of adaptation and the challenges faced by the coach. However, one cannot retreat from the value of speed at every aspect of the throw, thus my recommendation of using the front leg as a ramp, rather than a break on fluidity, and by using its levers sequentially to eventually generate greater speed.

In the twilight of my career, I now get tremendous satisfaction in helping to perfect the techniques of those likely to become our future Olympians, thus with a squad that has several fifteen years old males who can approach 60 metres, several young ladies, mainly foreigners, who can cast the spear regularly over 45 metres, and adult men and women who can all make 70 metres and 5O metres respectively, the future indeed looks rosy. Sadly, it is both energy and time consuming as every technical session needs to last around two hours, then add to this a specifically designated core strength session and a javelin specific strength session, then there is little time left in a week for the other events where I still have a staked interest.