An open hip angle can benefit the used lung volume and respiration.

The rider should still keep the hip angle nicely open, and the lower back soft.

This makes the rider's hip angle (between the thigh and chest) close.

As the horse lands, it moves away from the rider's body, which allows the hip angle to open and the rider to become more perpendicular to the ground.

The hip angle should still close backward.

Snapping up: When the rider throws the upper body upward, quickly opening the hip angle on the landing side.

Ducking: When the rider bends the hip angles too much and snaps the upper body over one shoulder.

Thus, the hip angle is not necessarily correlated to the topline of the croup.

Racehorses do well with hip angles of 20-30 degrees, trotting horses with 35 degrees.

The current revival of the asymmetric shoulder line can be traced back to Helmut Lang, who gave it a new hip angle.