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Post by wez on Dec 2, 2008 9:28:12 GMT 1
Great thread guys very interesting! Just reading through i think that everyone is basically in agreement that there should be no collapse on the braced side and left leg. What is so nicely pointed out in Wilfs article is that the human body is rather complex and achieving a strong braced blocking side is not quite so simple as sticking your left leg out! I've tried it myself and he's dead right that you just pike over the top of it I think that you can safely say a bending left leg that causes the javelin to drop and rise in delivery gives a concave pulling action, this loses momentum and makes for a messy flight on the jav with alot of vibration. On the other hand if the leg is a little bent and then braces and slightly hyper extends in the same difference of angle (like Zelezny) then the javelin path is still clean and straight with the biomechnical advantage of a more naturally compatible sequence of movements. I believe that it is a misnomer to say "throwing with a bent block leg" this is clearly not the same thing as bending it to 90 degrees and blasting off into the throw like a squat jump as is the mental image conjured by such statments. Please correct me if i'm wrong here.... but maybe the two disputing coaches in the begining just didn't quite understand eachothers point of view and were arguing the same thing in different ways. In simple terms yes we want a straight leg and braced blocking side but a leg and body that moves horizontally but stays stationary in the vertical plane is still straight and braced! and relax...
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Post by pembrokian on Dec 2, 2008 12:33:52 GMT 1
Wow !
What mighty contests arise from trivial things. Thank you all very much for your feedback; I think the dispute will end in a draw.
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Post by slinger on Dec 2, 2008 15:36:21 GMT 1
ok right here's my thinking and practise to do with what the left leg [for right handers] should do during delivery for the blocking phase.
imo you need to think what's the function of the block, i've written many times before that i think the role of the block is to provide a fixed point and base for the right hip to rotate around and work from, it also creates a strong bracing effect for the upper body to work against and allows run up momentum to be transfered up the body in a kinetic chain to the spear.
however most important to the block is that momentum has been allowed to carry through the delivery stride into the blocking leg via an early "striking" of the right hip - for most this is by a "soft" landing on the right foot [for right handers] where the right knee is allowed to continue forward and NOT where the athlete sits allowing a pause moment, incidently this imo is probably 90% of athletes in the UK struggle with...anyway i digress slightly.
when the right lands "soft" it gives the athlete the chance to go INto the block and not ONto the left leg like many do if they sit on their right leg too long....this going INto the block is what makes the block so effective as momentum hits the solid left side and this accelerates the right hip into the throw, which inturn the torso, chest, shoulder etc etc.....so the angle the left leg goes into the block is important - you should feel you slide into it, rather than land into it.
bio mech studies show an effective block as how quickly one was able to deccelerate the bodies centre mass after the blocking leg contacts the ground and zelezny for the most does it better than anyone.....IF the left knee was allowed to bend during this time it would show a slow deceleration of the centre of mass and this makes the base unstable to work from and doesn't give the athlete the greatest stretch - shortening that would occur if the left knee was as straight as possible.
my strongest element to my technique was my ability to transfer run up speed via what i did with my legs during delivery and block, so hopefully i feel well experienced in giving my views.
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Post by pembrokian on Dec 3, 2008 15:10:17 GMT 1
I notice from Sam's "freeze frame" that he throws very straight-legged; and he's never had any problems with his left knee.
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Post by slinger on Dec 3, 2008 16:11:01 GMT 1
he does, well it bends slightly then extends tbh, but an effective blocking action isn't as simple as the thinking "the left leg must remain as straight as possible" i remember seeing some bio mech info and andrey moruyev - an 87m man at best btw [sp please??] maintained a straight left leg during delivery but his block was poor as he failed to slow down his centre of mass anywhere near what was seen as acceptable for his block to create a reaction from the rest of the body to that of his fellow competitors.....reason being he planted and just let his hips keep going over the top of his left leg - a good block should see a "jolt" and the hips rise slightly from the reaction off of it. the key like i said previous is that momentum must go IN to the left leg, NOT fall ON to it like [apologies for this] sam does in his picture, due to his right foot landing heavy and him "sitting" here is the sequence for zelezny's WR and note 2 things... 1/. his ability to allow momentum to carry through the delivery via a soft right foot contact and allows his right foot to just flop over onto the toe prior to left contacting for the block - this initiates the early right hip strike prior to left contacting. and 2/. the angle at which his left leg is when contact is made for the block and the way his hips stay where they are pretty much for the whole delivery - someone may correct me but his hips moved no more than 6cm during this throw....this btw notes how strong a javelin thrower needs to be to maintain this position. i always liken a good block to feel like you've just been winded and it's like basically running as fast as you can then hitting something solid....the throw is then just a reaction from this.
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Post by ironbrew on Dec 10, 2008 23:07:41 GMT 1
Nice one slinger, another interesting point with JZ is his centre of gravity at the point of his right foot contact with the runway. His c.g. is actually in front of his right foot (as to most other thrower where the c.g. is behind) the effect is that he is capable keeping his speed. and thereby reducing his last step time.JZ last step 160ms, Backley 190ms Raty 230ms the time of the pulll is also quicker JZ 110ms Backley 140ms Raty 120ms. JZ last stride length is similar to other throwers Speed of c.g. when RF touches JZ 6.6m/s, Backley 6.4m/s and Raty 4.8m/s , speed of c.g in release moment JZ 3.2m/s, Backley 2.9m/s, Raty 2.6m/s. Quote "Jan get good last step that makes it possible to get all pressure to front leg, so he can use all power from his body and put it in to the Javal. Simply, Jans last step and pull is faster than others" This info came from Kuortane Sports Institute Kari Ihalainen Javelin Head Coach
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Post by slinger on Dec 12, 2008 20:32:12 GMT 1
superb iron brew, i really enjoy this kind of javelin discussion and superb points made regarding the way JZ allows his run up speed to be carried through delivery from right to left....i did read tom pukstys wrote that on JZ's WR his C of G of gravity was pretty much directly over his right, as opposed to being more forward - please correct me if i'm wrong however.
on similar lines i remember speaking to calvin morriss about Gatzioudis in the '97 worlds and on his bronze medal winning throw he certainly is ahead of his right on final RF contact and leads to him being very ahead of himself and a topped throw - an 86m practical stab!! Calvin reckoned if he'd of been behind it slightly more he'd of thrown gold medal distances and figures that would of been in excess of 3rd or even 2nd all time - and i can believe that as Gatzioudis was on one that day.
I also recall reading anders borgstrom saying that he does not coach final right foot placing to be ahead of the C of G, as it acts as a braking system to the run up speed and momentum.
back to JZ, for me though the main contribution to the fact he is quicker from right to left foot contacts than anyone else [btw for top throwers there is a strong correlation between time taken between these foot placements and distance thrown ie shortest time taken = bigger distance thrown] is the way he uses his right foot and lower right side to be exact, the fact his thinking is landing soft on the right and letting his knee just drop and right foot just flop over almost passively means he continues run up momentum very well indeed, his thinking also is after impulse to land both feet simultaneously - this means the left foot is well advanced than the right at final RF contact and ahead ready for left foot contact - more so than many top throwers.
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Post by ironbrew on Dec 18, 2008 19:37:48 GMT 1
Interestingly in another thread there is mention of creating lift from a bent left knee, in Zelezny's 1995 throw of 92.50m his raise of centre of gravity from the lowest to the point of release is 4cm his knee angle went from 183 degree on left foot touch down upto 195 at release. There are not many athletes who can achieve this degree of block most land slightly flexed then move to a near straight as possible as the hips rotate.
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