Speed Gain (Pelvis to Chest)
What it measures
Ratio of maximum chest rotational speed to maximum pelvis rotational speed in the downswing—a kinematic sequencing metric. It is not X-Factor: in Sportsbox-style wording X-Factor @ [POS] is the angular separation between Chest Turn and Pelvis Turn (degrees at the same phase), not a ratio of peak speeds.
Units: ratio
Why it matters
Summarizes pelvic-to-thoracic peak-speed sequencing—not positional X-Factor stretch degrees at fixed POS snapshots; ties to stretch-recoil sequencing language and Pelvis/Torso kinematic timelines.
Curated YouTube drill videos
Vector matches drill videos to your focus—contact, shot shape, start line, D-Plane.
Related metrics
Chest Turn, Pelvis Turn, Motion efficiency rank vs peers, X-Factor @ IMP, X-Factor @ TOP