SportsBox.ai 3D Player trackers at the Address phase (ADR), the official SportsBox Swing Position code for setup before motion. Chest Bend describes forward/back sagittal spinal flexion of the torso versus the kinematic baseline at Address. It is distinct from Chest Side Bend (lateral tilt) and from Chest Turn (rotation about the spine). Match the phase label printed beside the number in SportsBox as “@ ADR” and mirror the app sign convention for spine direction.
Units: degrees
Why it matters
Posture at ADR anchors every later comparison (TOP, DCH, DAH); small setup drift reshapes modeled shaft plane and torso angles through the swing.
When the number looks wrong or noisy
Tripod creep and camera yaw masquerade as bend changes—reset marks on the floor and lock zoom before diagnosing.