The Question This Article Answers
Babbitt observes the right hip and shoulder rotating around the left hip in the delivery phase and calls it closing the door around a hinge. Kipp confirms that the world record throw exhibited a COM velocity vector only 5 degrees off the throwing direction at release. Both are measuring something real. But where does the separation that produces that door-slam finish actually begin — and what has to happen between the back of the circle and the delivery phase to keep it alive all the way to the block?
WHAT BABBITT AND KIPP OBSERVE
In the Babbitt analysis of Alekna’s world record series, three delivery phase coaching cues are identified as interrelated. The first is “rotating the right hip and shoulder around, rather than into, the left hip” — a coordinated rotational movement in which the right side of the body rotates around a relatively stable left-side axis rather than translating directly toward it. The second is “closing the door around a hinge” — the right side as the door, the left side as the hinge. Together these cues describe a right side that travels around a fixed left axis with a long throwing arm radius, contributing directly to orbital path expansion and release velocity.
The biomechanical evidence supporting these observations is precise. The world record throw exhibited a COM velocity vector directed only 5 degrees off the throwing direction at the moment of release. The rushed first throw showed a 32 degree leftward deviation — meaning a significant portion of the body’s linear momentum was not transferring into the discus but leaking sideways away from it. The difference between 5 degrees and 32 degrees is the difference between a door that closes cleanly and a door that swings wide and misses the frame.
Kipp’s broader biomechanical study adds an important nuance. Prior research has reported positive associations between hip-shoulder separation and throwing performance, but those relationships have been phase-specific, sex-dependent, and not consistently observed across the throwing sequence. Kipp acknowledges that discrete kinematic measurements may be less sensitive to identifying the dynamic, time-varying coordination strategies that actually produce separation. In other words — the data can see the door closing. It has more difficulty measuring how long the door was being pushed before it closed.
Babbitt and Kipp are describing the end of the story. This article is about where the story begins.
THE HONEST QUALIFICATION
Before going further, something important needs to be said — the same qualification made in Article 4 of this series.
Late hip-shoulder separation followed by a hard left side block can and does produce a door-slam finish. Many elite throwers achieve exactly this. The right side builds its rotation through the middle and delivery phases, the left side plants and stops, and the stored rotational energy releases through the discus arm with significant force. This is a legitimate technique that has produced world-class distances for decades.
This article is not claiming that approach is wrong. It is describing something different — a technique in which the hip-shoulder separation begins much earlier, in the back of the circle, and must be maintained continuously all the way to the block. That earlier start creates a longer accelerating path for the moment arm. But it also places a specific demand on the throw that late separation does not: the right leg must land in perfect rotational balance at the center of the circle, or the early separation collapses before it ever reaches the block.
Late separation can survive an imperfect landing. Early separation cannot. The earlier the sling begins, the more precisely every subsequent movement must be executed to keep it alive.
WHERE THE SEPARATION ACTUALLY BEGINS
In the technique described throughout this series, hip-shoulder separation does not begin in the delivery phase. It does not begin in the middle of the circle. It begins at the back of the circle — in the wind — at the moment the Wind Connect links the upper and lower body and the lower body begins to lead.
When the pelvic tilt establishes the vertical axis and the Wind Connect locks the upper body to the lower body, the lower left side picks up and continues the backward motion as one connected unit. Then the lower body reverses and leads the rotation in the direction of the throw while the upper body stays back. At that moment — still in the back of the circle, before the throw has moved toward the front — the right hip begins moving away from the discus. The shoulder and discus arm, connected through the upper body to that rotating system, begin to trail behind the accelerating hip.
That is the first moment of hip-shoulder separation in this technique. Not in the delivery. In the wind.
From that moment forward, the relationship between the right hip and the discus arm is a sling — the hip leading, the discus trailing, centrifugal force pulling the implement outward as the rotational velocity of the system increases. For that sling to produce constant acceleration on the moment arm all the way to the block, the separation must never collapse. The hip must never stop pulling away from the discus. The discus arm must never catch up to the hip. The gap between them — the separation — must be maintained or increased from the wind to the release.
Every phase of the throw between the Wind Connect and the block is either maintaining the separation or destroying it. There is no neutral. The moment arm is either accelerating or decelerating.
THE SPRINT MECHANIC AND THE CRITICAL LANDING
The on-it-off-it sprint mechanic, described in Articles 4 and 5 of this series, is the movement that catches the right hip early and accelerates the separation. When the left leg converts from rotational to linear before the right leg completes its arc, it catches the right hip while it is still moving around the back and pulls it forward, away from the discus, at an earlier moment in the throw than conventional technique produces. The separation that began in the wind is now being actively accelerated.
But the sprint mechanic does more than create early separation. It determines the quality of the right leg landing — and that landing is where the early separation either survives or collapses.
When the sprint fires correctly and the right leg picks up with the hip flexor — moving forward and away from the discus, counterclockwise, in the direction of the throw — the right leg arrives at the center of the circle still moving in a rotational arc. It lands underneath the center of mass at approximately 120 degrees of knee flexion. At that moment, the rotation of the right side is uninterrupted. The right hip is still moving away from the discus. The separation is intact. The moment arm is still accelerating.
This is the landing the sprint mechanic was designed to produce. Not just a landing in the right place, but a landing in the right place while still rotating. The right leg does not stop the throw when it lands. It continues it.
When the landing is wrong — when the right leg arrives in front of the center of mass, or when it brakes the rotation rather than continuing it — the right side decelerates at the moment of landing. The separation that was built through the wind and the sprint begins to close. The moment arm, which was accelerating continuously, loses its acceleration. And no adjustment in the delivery phase can recover what was lost at that landing.
The right leg landing is the hinge point of the entire technique. It is where the early separation is either preserved and carried into the delivery phase — or surrendered before the delivery begins.
ALEKNA’S WORLD RECORD THROW — THE PROOF
The technical analysis of Alekna’s 74.35m world record throw confirms this sequence at every stage.
At the back of the circle, the left pivot is not yet completed when the right knee begins driving across the circle — the left fires before the right finishes, exactly as the sprint-first approach requires. The upper body is completely passive through the transfer phase — it is not contributing to the rotation, it is being carried by it. The discus is well behind, the chest is still facing slightly right, separation is already established and building.
The left foot then bangs down — aggressively, deliberately, a complete stop of the left side. The left arm, which has been waiting, opens only after the block fires. The right side, which has been rotating continuously since the back of the circle with the separation maintained throughout, has no choice but to finish through the discus arm.
The result in the data is a COM velocity vector 5 degrees off the throwing direction. Almost all of the body’s linear momentum transfers into the discus at release. Nothing leaks sideways. The door closed cleanly because it had been pushed from the very beginning of the throw — not just in the final moments of the delivery.
The 5 degree COM velocity vector at release is not a delivery phase achievement. It is the accumulated result of a hip-shoulder separation that was built in the back of the circle, maintained through the sprint mechanic, preserved through a perfectly balanced right leg landing, and released through a complete left side block.
WHAT CONSTANT ACCELERATION FEELS LIKE
When the separation is maintained continuously from the wind to the block, something happens in the throw that athletes describe in different ways but recognize immediately when they feel it for the first time.
The discus does not feel heavy. It feels connected. It feels like it is being pulled outward by the movement of the system rather than pushed by the arm. The athlete does not feel like they are throwing the discus. They feel like the throw is happening and the discus is going with it.
This is the sling relationship working as it is designed to work. The moment arm is not being muscled. It is being accelerated by the continuous separation between the hip and the shoulder, maintained from the back of the circle all the way to the moment the left side stops and the energy releases.
When athletes feel this for the first time — usually after weeks or months of building the Wind Connect, the sprint mechanic, and the right leg landing through the drills described in earlier articles — the distance often surprises them. Not because they threw harder. Because they stopped interrupting the acceleration that the separation was already building.
Constant acceleration on the moment arm is not something you do in the delivery. It is something you maintain from the wind. The delivery is where you collect what you saved.
THE CHAIN FROM BACK TO FRONT
The hip-shoulder relationship that Babbitt observes in the delivery phase is the final link in a chain that runs from the first moment of the Wind Connect to the instant the left foot plants at the front of the circle. Every link in that chain either maintains the separation or compromises it.
The Wind Connect establishes the first separation — lower body leading, upper body staying back, right hip beginning its earliest possible movement away from the discus. The on-it-off-it sprint catches that separation early and accelerates it, while sending the right leg forward with the hip flexor so it can land in rotational balance. The right leg landing under the center of mass at the correct angle preserves the rotation and carries the separation into the delivery phase intact. And then — at the front of the circle — the left side stops.
What happens when the left side stops is the subject of Article 7. But it is important to understand, before arriving at that moment, that the block does not create the energy it releases. The block only releases what the separation built. A block without separation produces a modest result. A block at the end of a continuous separation that began in the wind produces what Babbitt measures and what Alekna threw on April 14th, 2024 in Ramona, Oklahoma.
The door slams because of everything that happened before the left foot planted. The block is the last chapter. The separation is the whole story.
Each article in this series will be accompanied by video demonstrations covering the key concepts, drills, and terminology discussed. Follow along on Instagram and at davidwollman.com as those videos become available.
Next: Article 7 — The Block and Finish: How the Left Side Releases Everything the Separation Built
Dave Wollman · Second Eye Consulting · davidwollman.com · Dallas, Texas
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