Everything Track and Field Discussion Forums

A very important question that is asked only infrequently is "How much horizontal rotation do you need?

Horizontal rotation is sometimes referred to as rotation about the bar. It is the rotation that causes the jumper to rotate from a vertical orientation at takeoff, through a horizontal position above the bar, and then up-side-down into the pit.

This rotation is originates during the takeoff drive as the sum of two separate rotations:

1. Lateral rotation, which is rotation in the plane formed by the hips and shoulders (at their orientation during takeoff). Lateral rotation supplies the bulk of the rotation about the bar.

2. Somersaulting rotation, which is rotation in the plane formed by the spine and sternum (breastbone, also as they are oriented during takeoff). Somersaulting rotation, when used, provides only a small fraction of the rotation about the bar.

Indeed, I consider using any somersaulting rotation at all to be an advanced tecnnique, thus somersaulting rotation will not be discussed in this post. I would, in fact, avoid somersaulting rotation unless analysis of your bar clearance clearly shows that it is necessary.

So, what is the proper amount of rotation about the bar? The correct amount is: just enough to rotate your body to a horizontal orientation at the moment the center of mass reaches it's apex (highest point). If everything else is done correctly, the apex of the flight will be directly above the center of the bar.

Executed in this way, the body of the jumper can be held in a gently arched position throughout the flight and all parts of

the body will clear the bar by approximately the same amount (lumps, bumps, and other projections from the underside of the body not withstanding).

Some will claim that you should lift the feet at the last moment, but it is my opinion that raising the feet is unnecessary at best, and counterproductive at worst. This is because raising the feet will drop the butt, and when the jump is really close this can't be timed well enough to avoid catching something on the bar. Better to get the rotation about the bar exactly right and avoid the need to lift the feet.

Clearly, if you bend the knee too much you will have to straighten the knees so they are in better alignment with the arch in the remainder of the body. I think it is better to travel over the bar with the body in one flowing arch throughout the flight and avoid "drooping calves" altogether.

This isn't the whole story, but I'll start there and invite discussion. I'm sure I'll get some disagreement, because some people still think that a very arched body, and the resulting increase in rotation rate that it causes, is necessary. It is not; but more on that later.

Glen Stone

I've seen many a jumper hitting the crossbar with his head as a result of starting the rotation too early. As I see it, you have to lift off vertically and keep your head up untill your shoulders are higher than the bar,before bending your neck backwards to start the horizontal rotation. Am I right?

It seems likely to me that very young jumpers hit their heads because the are diving to get across the bar, rather than because they have too much rotation in a "normal"jump.

By a "normal" jump I mean one where they are leaning away from the bar till the takeoff foot is planted, and then leave the ground with their body oriented vertically. Most very young jumpers can't rotate that fast any way. Their curves would have to be very tight indeed to do that. Usually we have to be satisfied with getting good rotation and forget about getting perfect rotation with such young jumpers. (Which doesn't mean we shouldn't try.)

It is very hard for 10year-olds to start off leaning away-upright and then executing all the following steps. As I said before, they overdo one or the other. With advanced jumpers you can teach them to do most of the steps almost right. What would be the most important part to focus on when teaching the youngsters?

If I really had to choose, I would leave them with the knowledge of how to construct an approach. Even if they can't run it, and even if they can't construct it themselves (now).

I had a physics teacher in high school who said "this isn't part of the physics class, but I would like to expose you to this before you leave my class". With that, he proceeded to show us the 10 minute version of a lesson in calculus. I never gave it another thought until I started college and took my first calculus class.You might imagine my surprise when the professor launched into the basics of calculus and I already knew what he was talking about. That 10 minute introduction in high school made it SO much easier to deal with the idea several years later in college.

What I am trying to say here is: the approach is the foundation of the jump. If you can get them in the habit of laying out a rational approach - even if they don't understand it now - they will carry that habit with them as they grow to greater ability.

Having said all that, I think there are some basic drills they can do to develop some idea of how it is supposed to work, even if they are unable at their age to put it into practice. I think I posted them someplace, and if I can find them again I will repost them here for you.

What would be the relationship between speed and radius. Am I right when I say that you can keep the radius the same and get more rotation from a faster approach?

Yes, all other things being equal you can get more rotation by a faster approach. However, the purpose of the approach speed is to help you to develop an impulse off the ground.The speed is chosen to make that impulse as great as possible, and then the radius is chosen to produce the correct rotation.

The reason for me trying to keep the radius of the arch as wide as possible is the fact that I have students practicing on uneven grass surfaces. If I try to have them running a tight curve, they frequently slip and I am afraid that they might pick up a injury. I realize that I have to increase their rotation rate as they frequently knock the bar with their lower legs.Any suggestions.

What you do in that situation depends on what you are trying to accomplish - what is your goal. My goal is always to be looking to the jumper's future. Under your circumstances I would sacrifice immediate improvement in the jumper's performance in favor of teaching the correct takeoff. I would rather that the jumper learn to take off correctly so that when the jumper is older, stronger, and bigger he/she will have a technique that is enduring.

I also believe that the best jumps will be attained by a vertical takeoff and however much rotation you can get by staying in the curve until the takeoff foot is on the ground. Even if the curve is too wide for optimum rotation, you will do better than any other method.

Hi,

Thanks very much for this comment. It help me to think about my ideals.

Tks again and pls keep posting.