Most tension doesn't stay where it starts. Fascia is one continuous sheet from scalp to feet, so the tightness in your neck by 3pm, the bloat after a desk day, and the ache you wake up with can all trace back to a few overlooked spots: the base of the skull, the psoas, the mid-back between your shoulder blades. Sit 9+ hours a day, carry stress, or stay in one position too long, and adhesions build up there. The surrounding area stops moving right, even if that's not where you feel it.
The XELO ball is soft enough to sink into those spots without bracing against the pressure. That's what lets fascia actually release instead of tightening back up. Most people feel a shift in the first session. Areas that have been locked longer take a few more.