#717 The "Secret" Downswing: Why Your Pelvis Starts Moving Before You Reach the TopThe Myth of the Top

Traditional golf instruction often describes the swing as a simple sequence: finish the backswing, reach the top, then start the downswing. Elite 3D biomechanics shows something different. The backswing and downswing actually overlap. Different body segments change direction at different times—a process called Temporal Separation. One of the clearest examples is the pelvis: it begins moving toward the target before the club reaches the top. **What the 3D Data Shows** WatchItGolf PGA reference data for Pelvis Sway: - **P1 Address:** 0.0" - **P2:** −0.2" - **P3:** −0.5" - **P4 Top:** +0.3" - **P5:** +2.1" - **P6:** +3.9" - **P7 Impact:** +4.3" The key is the change from P3 to P4. At P3, the pelvis is 0.5" away from the target. By P4, it has already reversed to +0.3". That means the pelvis is moving toward the target while the club is still completing the backswing. The exact number varies. LPGA reference data shows approximately −0.1" at P4. What matters most is not the number, but when the pelvis changes direction. **Pelvis vs. Lead Knee** At P4, something fascinating happens: - **Pelvis Sway:** +0.3" - **Lead Knee Sway:** −2.5" The pelvis has already reversed while the lead knee can still be positioned toward the trail side. The body is not a rigid block. The hip, knee and ankle can reorganize independently. Therefore, the lead knee does not necessarily "trigger" the downswing. **Avoid the Emergency Transition** If an amateur stays on the trail side too long, everything must happen at once: **Shift → Lower → Rotate → Arms → Club** Elite players organize the movement earlier: **LOAD → REVERSE → TOP → ACCELERATE** Early recentering maintains momentum, reduces the need for a violent lateral recovery and prepares the lead side to use ground reaction forces. **Load Before You Extend** The sequence continues: **RECENTER → LOAD → LOWER → EXTEND** As the pelvis recenters, the golfer loads and lowers into the lead side. The lead knee's early role is to accept force, not immediately straighten. Rapid lead-leg extension happens later, around P6, helping create vertical force, rotation and energy transfer. **Coaching with WatchItGolf** Don't just analyze positions—analyze the curve. Does Pelvis Sway change direction between P3 and P4? If it is still moving farther away from the target at P4, recentering may be delayed. And remember: Pelvis Sway is not Center of Mass. They are related concepts, but not the same measurement. **The Key Feel** **"The pelvis goes while the club finishes."** Feel the pelvis begin moving toward the target while the club is still completing the backswing. **LOAD → RECENTER → LOWER → EXTEND → ROTATE** The pelvis doesn't wait for the club to reach the top. **The downswing has already begun.** - My Blog⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ - ⁠⁠⁠⁠**⁠**⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠The Explainer⁠⁠⁠⁠**⁠**⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ - ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠www.ecoach360.com⁠