How do you calculate hip flex-ion angle?

The hip flexion angle can be calculated by measuring the angle between the trunk and the thigh when the hip is flexed. This can be done using a goniometer, where one arm is aligned with the trunk and the other with the thigh. Alternatively, you can use a digital inclinometer or motion capture technology for more precise measurements. The angle is typically measured in degrees, with 0 degrees representing the anatomical position of the hip.