Coaching Young Athletes

Why a J-Curve Beats a C-Curve in High Jump Run-Ups

When we ask kids to perform a high jump run-up it will often follow a “C-shaped” circular path.

They are usually copying their peers or have misinterpreted what they have seen good high jumpers do.

Preferably, a high jump run-up should be more like an upside-down “J”.

The athlete runs along a straight path before leaning into a curve for the final few strides toward the bar. They take off at the mid-point of the curve.

The straight-ahead section of the run-up builds up speed. The curved part of the run-up builds up the necessary forces to put the athlete in the best position for an effective take-off.

The C-curve, without an initial  straight section, lacks a build-up of momentum. This negatively affects the ability of the athlete to generate the necessary forces and take-off position to carry themselves over the bar. 

There are problems caused by running a C-shape:

• It is difficult to build-up speed and maintain acceleration right up to the bar.
• The  athlete spends part of their time running away from the bar.
• The run-up becomes longer run than necessary.
• Additional energy is used.

Some benefits of the J-curve are:

• It facilitates a build up of speed. 
• It better allows the generation of the advantageous forces of running a curve.
• It only needs the curve and lean to be held for a short time.
• It allows entry into the curve at a greater seed.

J-curve jumpers actively enter the curve with momentum. C-curve jumpers enter the curve from a stationary position and with no momentum.

Kids will naturally want to run a C-curve. Don’t be too harsh in your response to them. Simply:

1. Start them a little wider on the runway than they initially want to stand.

2. Turn them 90 degrees so they will initially be running in a direction perpendicular to the extension of the bar rather than parallel to the bar.

3. Guiding their path with markers can help.

In conclusion, the J-Curve is the clear winner over the C-Curve as the optimal flop high jump run-up shape. The “J” shape combines a straight section for speed build-up and a curved section for force generation and take-off positioning. It paves the way for better speed and force generation, and an efficient entry into the curve with momentum. We should encourage young athletes to adopt the J-Curve run-up by starting them wider, orienting them perpendicular to the bar’s extension, and providing helpful markers. Used effectively, the J-Curve can help young high jumpers leap to greater heights.

Further reading

The Flop High Jump Run-Up Guidebook by Coaching Young Athletes

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