Bent Lead Arm
What is actually happening
Your lead arm bends because your body stopped turning and your arms wanted more backswing anyway. Somewhere past P3, halfway back, the shoulders hit their limit and the elbow folds to keep the club moving. It feels like a bigger swing. It's actually your swing's radius collapsing in the middle of the swing.
What it costs you
Your swing is a circle and your lead arm is its radius. Bend the radius going back and you have to recreate the exact same bend coming down, or the bottom of the swing moves and contact moves with it. That's the fat-thin lottery. A soft arm is fine. A folded one is expensive.
Keep the lead arm long, like the spoke of a wheel, and let the backswing end where your turn ends. Shorter with a long arm beats longer with a broken one.
Turn-Ends-It Checkpoints
Swing to the top in slow motion and stop exactly where your shoulders stop turning, wherever that is. Look at your lead arm. Long and soft, not locked, not folded. That's your top, and it's probably shorter than the one you've been making. Now find out what the extra length was made of: keep pushing past that spot and watch the elbow fold and the posture give, because that's all the old backswing was adding. Come back to the real top. Make five slow swings that stop there, then hit five balls swinging to that same spot at speed and no further. It will feel short. The ball won't care, and your contact will tighten almost immediately. Film one face-on and check the arm at P4. A long spoke makes a round wheel.
Is this the one costing you shots?
Film one swing and the analysis checks for it at every position, on your video.
Analyze my swing freeCurious how the measuring works? See what we measure at each position.