and to add, my fav long jumper of all time, Mr Pedroso, had a take angle around 24 degrees and sometimes more…
Wow that’s low compared to theory. Yes I believe you guys. I read some articles particularly ones by Linthorne (an ex Sydney University professor) which I should have read before entering the debate! It would be interesting to see the effective launch angle relative to the position in stance where force application is greatest and where EMG activity is highest. I think they (Linthorne et al.) are working on computer simulations as Brunel University. I know you guys were going to look at assisted jumps, Rob Newton has done work previously and is doing some at Edith Cowan University currently. Look forward to seeing the thesis.
I think the main problem here is how to measure take-off angle. Could you elaborate, I still think measuring from 2-d changes in COM, with the approximation being the hips although COM it’s position relative to the hip quite dramatically in the last step of a jump and not from foot angle.
I have always taught to measure take off angle in the long jump as the angle of the take off leg JUST before take off and the free leg. So the line, goes from floor up the front of take off leg at which ever angle it is, to where it meets the COM and then horizontally along the free leg.
I really need to draw it, so ill try to attach something later…
And Jeremy: I have also read Rob Newtons work, actually have it on my computer and will use it as one refernence for my thesis. The work for it has just got underway and should be really good. I am looking forward to seeing if my method of suspention jump squat training can beat the gold standard or complex training.
For instance, we can say “to be an elite jumper you need to be able to jump 8m and this can be done either by having high takeoff velocity and lower takeoff angle or lower takeoff velocity and higher takeoff angle” and it is 100% true. At the same time, it can be true to say we can’t have both maximal velocity and maximal takeoff angle. This is because the 2 variables are inextricably linked…for a given performer, as one variable goes up the other goes down.
With this in mind, what’s the best way to takeoff? Well, it kinda depends on your strengths and weaknesses. Putting the foot out far in front of the COM will definitely produce a big vertical component at takeoff. HOWEVER, it can also potentially lead to a loss of horizontal velocity, especially if the setup for that takeoff has the athlete putting the feet out in front in the last couple steps.
This brings me to another point. What is more important - takeoff velocity or takeoff height? To be honest, from a mechanical standpoint it isn’t even close. Velocity is far and away the most important variable in any projectile motion situation when distance is the primary concern. It’s not even close. Distance is a product of velocity squared (velocity x velocity) while only a product of projection angle. This means that velocity has a much bigger impact on the distance traveled. In fact, my research on the throwing events (where these questions also arise) suggest that the release velocity can explain up to 95% of the variance of a performance. Basically, that means, if you tell me what the velocity is, I can tell you whether it’s a great, good, or bad performance. The same cannot be said for takeoff or release angle.
Thanks, Mike. Exactly what I was trying to get across to Nick. For every jumper there is an optimum take-off angle and trajectory. Nick claims that this optimum varies directly with the speed of the jumper. I just want to see some evidence. He claims 200 references to support his contention, but has offered none here.
It seems to me that the trade-off between horizontal and vertical velocity is analogous to the trade-off in sprint speed between turnover and stride length. An increase in one leads to a decrease in the other. To say the way to go faster is to increase stride length while maintaining turnover rate is obviously true in the world of arithmetic, but not in the real world of sprinting or sprint coaching. Seems to me that the same applies to the question of take-off angle in long jumping. In both cases, every sprinter has an optimal combination.
Mike also stated that the optimal take off angle does depend on the speed of the jumper…i assure i was not wrong!
the optimal angle of take off is different depending on the speed of the jumper….what dont you understand here? ? ?? ? ?
it also depends on the hip height/ leg length of the jumper…for someone who runs 11m/s, their take off angle will be less than a jumper who runs 10m/s but jumps the same distance
Re-read this thread before you say that i’m saying in-correct statements. Get YOUR facts right first please.
haha this post got intense. I don’t think anyone was wrong with this one. Obviously everyone is different and needs to find out whats right for them. In any horizontal jump its important to be fast, and i have personally noticed that i jump much better when i am still accelerating and pull my jump leg through fast and underneath me so if my leg is in front of me, which it often is due to concentrating on high jump over the years, that I slow myself down and go too high and only end up at about 6.70 rather than 7.20’s. With that said what your doing Nick is what is probably right for you and you do it becuase youve been coached on it and it works. I don’t understand why all this turned into such a battle
i have no idea either john…The initial statement was, you need to have your foot infront of your COM for a optimal take off (CORRECT) and also a slower jumper needs a bigger take off angle to jump as far as a faster jumper (CORRECT)
Yes, but the problem is how to minimize speed loss while having a big vertical component in the jump. From my own experience it’s possible to get the same vertical lift while heel striking and while not doing so, with the latter jumps being about half a metre longer than the heelstrike ones, and even though the app speed in the heelstrike jumps was much higher than in the other ones. The only explanation I can find to this is horizontal speed loss due to heelstriking’s massive braking.
yeah true…like Mike said, its a trade off…its not possible to achieve optimum in both at the exact same time…
but, i dont think the braking effect is THAT huge…
I have biomachanics analysis of Greg Rutherfords 8.20m LJ this year, on that jump, he put his foot WAY OUT IN FRONT and did not lose a significent amount of speed from 1m-board.
Mike also stated that the optimal take off angle does depend on the speed of the jumper…
Sorry you are taking this so personally, Nick. I am only interested in the science here. Mike may have said what you attribute to him sometime or somewhere, but he did not do so in this thread. Not unless you think that the arithmetical truth that to jump as far as a faster runner you have to stay in the air longer is useful in the real world of biomechanics and the trade-off between horizontal and vertical velocity. Why don’t you just post one of your 200+ references?
As I recall, you are 7.5 M jumper. You seem to believe that the key to becoming an 8.0 jumper is to jump steeper than the 8-meter jumpers. I was a 7-meter jumper, so I suppose you think I should jump even steeper than you. I am pretty confident that, given my speed, power, etc. I found the optimal take-off angle for myself. I sincerely doubt that trying to exceed your take-off angle would have done me any good. I have certainly seen plenty of jumpers who I think would benefit from a steeper take-off, but that is not because they are slow.
Again, just give me some science (physics and biomechanics), not just assertions or math based on the premise that two vectors (horizontal and vertical) are independent when they are not. If you are right, I will apply it gladly, but I am unable to simply take your word for it. Sorry.
you not taking my word is fine…but your taking Mikes, which is the same as mine…we said the same thing…
how many times do i need to repeat it…
a slower jumper needs to have a bigger take off angle than a faster one to jump the same distance…that is all i said, and it is true…
In England, we have an 8m jumper, he runs 10.2 m/s at best over the final 10m of the approach (same as me right now). His rate of force development has also been tested against mine and we are just about even. Difference, his take off angle, ie the height he gets on his jumps is outstanding and better than mine right now…that is the difference…
I fully understand the need for speed, and as you can see, work on it very often and wil become faster i am sure…i never said the key for me to jump 8m is JUST to have bigger take angles, it is important yes, but my speed, strength, technique etc is also important…
I simply said, what i have repeated a hundred times…
All people should take from this discussion is something you seem to be missing…
1- both speed and take off angle are vital for jumping performance
2- jumping 8m or any distance can be done very differently, depending on speed or take off angle
3- optimal angle for LJ is around 17-24 degrees
4- the faster you are the harder it is to acheive a big take off angle
5- its not possible to acheive both optimal results in each element individually in the same jump
Final thing that i would like to add, although science is very important…coaching is not science alone and never will be, a practical element/ knowledge must be included in every program.
1. The optimum take-off angle for each jumper and each jump a jumper makes is different meaning it’s highly variable, subject to such attributes as velocity of the COM at take-off, length of ground contact at take-off, leg stiffness(strength) at take-off,etc. Those values differ based on the jumpers ability to accelerate, the jumpers ability to withstand high-force, and skill with which they jump, not to mention fatigue and others attributes that may directly or indirectly influence performance.
2. The take-off angle should be measured from movement in the COM. This is best approximated by using the hips as guidance. Not from the foot through the hip.
3. The COM is hard to measure because the COM’s relative position to any point on the body moves the most during ground contact. It’s not a fixed point and the movement of the COM is directly affected by changes in forces present in the system.
4. The goal of any jumper should be to get faster while keeping about the same jump angle as the had previously with their best attempts. See my posts in Jeremy’s Newtonian Mechanics of Sprinting article.
5. Teaching height to a horizontal jumper is no-no in my book. It teaches and reinforces bad habits such as excessive braking and guidance problems to the board because the jumper is focused on getting height in the last few steps to the board. This is why I don’t teach pop-up jumps or rarely cue driving the leg through. However, if you teach acceleration,speed maintenance, and a stride pattern you can lengthen an approach to get more speed once the athlete masters the ability to jump for a given # of strides.
6. For runners of 2 different speeds the slower runner needs a larger take-off angle than the faster jumper to beat them. No jumper in the world has the ability to jump at 45 degrees on take off. With that said if a slower runner at take-off outjumps a faster jumper at take-off it all comes down to the slower runner having a larger take-off angle if their control of their COM on landing is the same.
Coaching is not indeed just about the physics involved it’s about getting the athlete to produce the best physics possible according to their current skill and abilities during performance. That requires instruction, feedback, cueing, conditioning, motor learning, motor development, and motor control.
however we have differant philosophys where number 4 and 5 are concerned…but that is not to say either of us is wrong…
heres why anyway,
mastering a jump at a given no. of strides in my book means a few things,
1 - achieving optimal height
2 - demonstrating the ability to penetrate the board down and back sufficiently
3 - being able to control over rotation
Now, these 3 will very often change when a jumper adds or takes strides away. For example, right now, i may be able to get all of these correct from 11 strides, but not from 13+ strides. Therefore i am not ready to move forward with my technique development just yet. Something simular to this was used by John Crotty, one of UKA’s national jumps coaches, and it just stuck with me as being very practical.
In my opinion achieving height at take off, is very much about phyical ability but also about correct positioning at take off, and this should be taught and re-enforced.
a slower jumper needs to have a bigger take off angle than a faster one to jump the same distance…that is all i said, and it is true…
All people should take from this discussion is something you seem to be missing…
1- both speed and take off angle are vital for jumping performance
2- jumping 8m or any distance can be done very differently, depending on speed or take off angle
3- optimal angle for LJ is around 17-24 degrees
4- the faster you are the harder it is to acheive a big take off angle
5- its not possible to acheive both optimal results in each element individually in the same jump
Every point you list is exactly what I have been saying, except #4, which is what I am questioning and what I am asking for evidence of. Of course, a slower runner has to jump higher with a bigger take-off angle to jump the same distance as a faster one. That is just simple math. But increasing the take-off angle will normally decrease the speed, so a steeper take-off angle can increase jump distance or decrease it. It all depends on whether your current angle is higher, lower or equal to optimum for you. That’s why they call it optimum. If you can steepen your take-off without corresponding reduction in speed, then great. That would simply mean that your previous angle of take-off was below optimum and now it is better. But I have seen many jumpers who get great height, but lose a great deal of horizontal velocity to do so, resulting in a short jump.
