X-Factor
The X-factor is the measured angle between the shoulder and hip turn at the top of the backswing. A large X-factor — typically 40–55° — correlates with higher club speed among tour professionals.
First quantified in the 1990s by Hogan Institute researchers, the X-factor captures how much the shoulders turn relative to the hips. Greater separation means a larger stretch-shorten loading. X-factor "stretch" — the slight increase in separation at the very start of the downswing as the hips fire first — may matter even more than the static top-of-backswing measure. Hip mobility, not flexibility alone, largely determines how much X-factor a player can create without losing posture.
Example
A player with 90° of shoulder turn and 40° of hip turn has an X-factor of 50° at the top — in the range of long-drive competitors.
Related terms
- Hip–Shoulder SeparationHip–shoulder separation is the angular gap between the hips and shoulders at the start of the downswing. A larger, well-timed gap stretches the core and releases into club speed.
- Kinematic SequenceThe kinematic sequence is the order in which body segments accelerate and decelerate during the downswing: pelvis → torso → lead arm → clubhead. Each segment slingshots the next for maximum speed.
- SeparationSeparation in the golf swing is when body segments rotate at different rates at different times — most importantly when the hips lead the shoulders at the start of the downswing, creating torque.
Related guides & benchmarks
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