If you are male, i vote for mechanical injury, & extreme sports are a veritable breeding ground for sacroiliac joint (sij) injury, i.
e., ligament injury, ligment laxity, and sij subluxation (a partial & self-reducing type of dislocation
). In my clinical experience skateboarding is greatest cause of sij injury. In females multiple childbirths and joint hypermobility
syndrome are primary causes.