Long Jump Breakthrough

1. When you run (before jumping) your one leg is stretched forward and other behind.

2. In running both feet are never simultaneously on ground (in air yes)

So putting both the feet at same place together on ground would cause a loss in momentum, in the effort to do it.

3. When you land, you stretch your one leg forward to maximum (for gain) and then topple over with that as hinge. If you try to do thet with both legs you will fall back reducing the length of jump.

BTW- kangaroos do it and successfully but for them the adfantages are three legs (assuming the tail can be considered as one) and the tremondous amount of the spring energy stored in these.

It seems to me that there would also be a loss of momentum due to the opposite of the "planting" leg.

When jumping off of one foot the opposite leg leads the jumper through their path. As he/she plants with the left, the right leg is then thrown with as much force as possible (in a sort of flying knee strike you would see in MMA fights), and at that same moment the jumper pushes as hard as possible off of the ground with the left (planting foot).

Just from basketball experience, yes, you can jump higher when jumping with two feet. The problem occurs due to the forward momentum of the jumper.

There are two ways that one could plant with two feet:

1.) Side by side facing forward. The problem with this is that the time it takes for the second leg to move forward enough and plant next to its fellow is far too great with the speeds at which most runners are moving at the time they jump. By the time the second plant is made, the runners momentum has carried them too far forward and they have either fallen or are very close to falling.

2.) Side by side facing perpendicular to the way you are jumping. In this case you would plant with the left foot, let your right swing around and when it came time plant and convert into a jump. This is much more managable seeing as it will be easier to get to a wider base, and thus will have more balance. And the jumper would be able to squat into a jumping position as the opposite leg swung around. Saving time.

It is a sound idea since a higher vertical would translate into a longer jump but it is all about timing. And jumping off of two feet just takes too long. If you watch videos of people jumping off of two feet for a dunk, almost completely verticle jump, they get extremely low before they start their jump (as compared to a single footed jump). That is where this extra vertical height comes from.

The reason faster horizontal speed also translates to a higher jump while using one foot comes from a sort of "launching" effect. I like to compare it to the pole vault where the planting foot is the pole. As you plant your foot, you place your body weight over that leg so that your momentum carries you up and over the the leg as you extend it and push off the ground (much as the pole flexes due to the force it exerts on the ground, and accelerates the vaulter up and over the bar) and little energy is lost in the latteral directions.

Sorry so scattered, I just started typing as I thought about your OP. I am by no means an expert in the field as you may be, but these are just some issues that I think may factor in. If I am wrong in my reasoning please say so, best ideas come when thinking about why others are wrong.

Dear Anonymous:

You make an extremely good description of the Mechanics of Jumping.

The human body is in fact a very complex machine that hopefully can be described using the Laws of Kinematics and Dynamics.

But the problem is that this particular machine is so complex, taking into consideration the non-elastic behaviour if muscles and even skin, that you can hardly complete a good description. Even worse: We must take into consideration the psychological behaviour.

This is the main reason why in my discusions with the best athletic trainers, we never come to an acceptable agreement.

So I am not expecting any adherence to my views in this Forum.

All I can say is: The video is really bad, but I think that if you make a loop and watch it in slow motion, may be we can reach some conclusions.

In order to save difficult to draw frames, the previous jump and the final landing are not shown.

One very important fact that causes most of the misunderstandings.

When a machine, no matter how complex it may be, is not touching the ground (Or anything) it CANNOT lose or acquire Momentum using its internal forces.

So the fact that the runner has to move the leading leg backwards in a fast way, in order to equalize both feet, in a backwards motion, before impact with the Ground, DOES NOT make him/her lose any MOMENTUM

chorete

First off you need not make any apologies on this forum. And living in the mountains in the south of Spain sounds like a pretty good gig to me.

I would suggest (if you haven't already) study some slow motion footage of a jumper once they hit the take off board. You'll notice they squat a bit on their take off leg. This gives them just a little more upward push without scrubbing off too much speed. I would be willing to bet if a series of high speed work was done on your idea you'd see a pretty significant speed loss at the moment of take off.

Your idea is to double the upward push, I get that. But although you might make a nice gain there the losses in forward speed would be greater. The net result is a shorter distance achieved.

Please look at a very unscientific test of the second part of the "Long Jump Breakthrough" by an untrained child.

Although not clearly shown in the VIDEO, there is a definite loss of momentum by the impact of the feet with the ground, that still have some forward velocity.

The landing part of the Jump has been eliminated. I consider it not too difficult.

I'll need some really slow motion videos to study the kinematics of the new Jump

http://www.youtube.com/user/chorete3003

chorete

Chorete, one of the things not discussed here is the athlete himself (herself?). One of the specific training elements used by long-jumpers is plyometrics. This training is intended to improve the 'explosive' release of energy at the board. This is also why some jumpers sort of bounce or bound the last few steps before the jump.

It must be considered that I am dealing with this Jump from an absolutely mechanical point of view.

So if you improve the performance of the muscles at the moment of the leg extension, you'll have more effect with two synchronized legs.

The poblem here is purely mental. You need a perfect synchronization of both legs plus, even more difficult, a delicately measured backwards acceleration so as the longitudinl impact on the ground is minimized. or zeroed.

This is what happens in a well coordinated running gait. You can hardly hear the impact of the feet (Hear the Video BRENES 21) But the impact of the two feet at the last jump is very noisy, indicating a large loss of Energy and Momentum. This loss is clearly NOT DUE to the height of the fall, that is more or less the same as in standard steps, but DUE to sudden loss of horizontal velocity.

I wished I could have good instrumentations. For example a force gauge at the jumping board, would disregard all jumps where the gauge shows any force in the direction of the run. Good jumps would be determined by the absence of horizontal force, or even better by a force contrary to the direction of the run.

chorete

Clearly this Jump appears to be of better efficiency than the Standard Jump, but it needs a LOT OF TRAINING