Why would you say X-band walks are better?

From my understanding clamshells are better initially and then x-band walks are the progression. Meaning the person does not want to be doing clamshells forever as X-band walks are more functional. However the clamshells do serve their purpose in that its more controlled and their is higher glute medius activation relative to the TFL when compared to the x-band walks. Chris powers is the one that did the study. Hes the world leader in patellofemoral pain syndrome and first one to prove their is a link between hip mechanics and knee pain. He also recommends starting with clamshells at phase 1 of the physiotherapy. Although he does some variations of it as well. But I also do x-band walks just not as often as the clamshells right now.

In regards to the FMS, I will copy and paste the email I got of the results. In summary tho the biggest finding was tight hip capsule on my right side.