Why do you run in a curve? The J-shaped approach explained: straight acceleration, curve radius, and how many steps you really need.
The question almost every beginner asks: why don't you just run straight at the bar? The answer is simpler than it sounds: the curved approach creates centrifugal force that automatically tilts you inward, away from the bar — exactly the lean you need for the backward takeoff.
This approach has a fixed shape and is called the J-curve: a straight section to build speed, followed by a curved arc toward the bar. The shape resembles the letter J — hence the name. The straight part is usually 4–6 strides, the curved part another 4–6 strides.
The radius of this curve is surprisingly small: for men it averages around 8.3–8.6 m, for women 9.5–10 m — barely longer than a city bus. It's exactly this tight arc that creates the centrifugal force which leaves you leaning so far by the end of the curve that the backward rotation over the bar happens almost by itself.
Start with the last step: stand where you want to take off (slightly offset from the bar) and count your steps backward from there. That way you find your personal starting mark instead of guessing it.
The first 4–6 strides run completely straight and are purely for accelerating. What counts here isn't technique but controlled pace — sprint off too fast and the curve becomes unstable.
From the mark on, you run the curve as if going around an invisible barrel. Your upper body naturally leans inward — that's centrifugal force, not a conscious lean-in. Important: the radius is individual and must be found by trial and error, not copied from another athlete.
The penultimate step before takeoff is mechanically the most important of the entire approach. It's deliberately a bit longer than the others, drops your hips slightly and loads your takeoff leg like a spring — similar to bending your knees before a squat. If this step is the same length as all the others, the loading is missing and the jump comes out flat.
The last step before takeoff lands flat and dorsiflexed — foot pulled up, not on the toes. Your upper body stays upright, not leaned back. This combination of a flat foot plant and an upright torso is exactly what makes the takeoff in the next guide possible at all.
An unstable approach is one of the most common causes of twisted ankles even before the actual takeoff. So run the curve slowly first, in shoes with good grip, before increasing speed.
Warm up hips and ankles specifically before every approach session — the sideways load in the curve is unfamiliar for bodies used to running only in straight lines.
Use chalk or tape to fix marks for the start, curve beginning and penultimate step. Most high jumpers keep readjusting their marks over weeks — that's normal, not a sign of bad technique.
The curved approach creates centrifugal force that automatically tilts the body inward, away from the bar. This lean is the foundation for the backward rotation at takeoff — without the curve, this effect is entirely missing.
Beginners usually start with 6–8 strides, elite athletes use 8–13 strides. More important than the exact number is that the stride count stays constant — that's what makes the approach reproducible.
It's the step right before the takeoff step. It's deliberately longer, drops the hips and stores elastic energy in the takeoff leg — the mechanically most loaded phase of the whole approach.
By trial and error, not by copying. As a guideline, the radius averages 8.3–8.6 m for men and 9.5–10 m for women — your coach helps you find the curve that fits your height and speed.
High Jump: The Perfect Takeoff