Early extension: the hip move you can't feel

Draw one line up the back of your trousers

Film a swing from down the line, with the phone behind you on the target line. Pause at address and draw a vertical line touching your backside.

Play it forward. Your hips should turn, and your lead cheek should move back behind that line as you open. Early extension is the opposite: your pelvis travels toward the ball before impact and your body stands up. The Titleist Performance Institute defines it as any forward thrust of the lower body toward the ball during the downswing.

Pebble Swing calls that mark the tush line and tracks the hip landmarks across the frames it cuts from your video, so the movement comes back as a measurement.

Most golfers do it, and most tour players don't

67%of the golfers TPI has screened early extend

TPI has screened over 90,000 golfers. Around 67 percent early extend. Of the 100-plus PGA, European and LPGA tour players they have tested, all but about one stay off it.

It is easy to miss in your own swing. Standing up through the ball feels strong, and the feeling arrives at the same instant as the strike, so it gets filed under good swing or bad swing.

It gets the club stuck behind you

When the pelvis goes at the ball, your torso has to rise and your arms run out of room. TPI puts it as the arms and club getting stuck behind your body, and the forward shaft lean you were trying to keep disappears.

Two misses that look like opposites come out of the same move. Leave the face open and the ball blocks right. Save it with the hands and you hook it. TPI adds fat shots, thin shots and the shank to the list, and has a separate article on what the move costs you in power.

Extending is fine. Extending early is not

Adam Young makes the point that extension itself is necessary: it creates speed, balance and a good hand path. Tour players extend hard through impact. The difference is when: after the club has come down, not instead of bringing it down.

It is also usually a symptom. A steep shaft or an open face leaves you nowhere to swing except up and out of it, and the hips back out of the way to make room. TPI links it to a physical limit as well: golfers who cannot sit into a deep squat struggle to stay bent over while they rotate.

The drills coaches use

Put a chair against your backside at address and keep contact with it while you swing. Half speed first. Going back, the trail cheek presses into the chair; starting down, the lead cheek stays against it. The moment you lose the chair is the moment you early extended. Ludvig Aberg used this drill growing up.

A wall works the same way if you have no chair: at least one glute touching it as you start down. TPI's Picket Fence drill teaches the hips to turn without drifting forward, and their deep squat work addresses the mobility underneath it.

Then film the same swing on the same line and draw the line again.