Bending the back instead of tilting the hips.
With good posture, the back is straight. Tilting the hips/pelvis and not bending the back will put you in a more stable position.
From your tailbone to the back of your head is a straight line.
Check your hip tilt- is your belt buckle/pelvis pointed at the ball or to your front?
Stand tall, tilt your hips versus bending your back.
Correct setup posture is primarily achieved by the forward tilt of the hips — not bending at the waist or back. A median angle of about 30 degrees.
Notice how the angle stays the same