I often refer to assessing SGIS in standing as a first movement assessment for any unilateral lower quarter condition. I shot this video because it's an often requested one!
If a patient's DP is SGIS, sidegliding works better than sidebending. In sidegliding, you or the patient most likely reach end range without rib on iliac crest obstruction as you would in sidebending. The assessment itself is important because as the MDT Diplomats would tell you, "You miss a lot of shifts that are not visible." This is not saying the patients with a loss of SGIS toward the involved side are laterally shifted, but they do have a load bearing intolerance for whatever reason. Getting them repeatedly shifted toward end range TO the involved side often makes many hip, knee, and lower leg pains that happened insidiously to centralize and improve.