Symptoms of sacroiliac joint dysfunction include: Pain in the lower back, (usually only on one side), hip pain, discomfort with bending over or standing after sitting for long periods, improvement in pain when lying down. (physiologicnyc.com)
The gluteus maximus produces a number of joint actions, including: hip extension, trunk extension, posterior pelvic tilt, hip external rotation, hip abduction (upper fibers), force closure of sacroiliac joint, force transfer through the ITB, and even force transfer through the tensor fascia latae. (strengthandconditioningresearch.com)
[159] I am prepared to accept some present minor low back injury related to a strain of the left sacroiliac joint causing mild pain at times of prolonged lifting, bending or crouching but I also do not consider that this pain has been disabling to any of the plaintiff's activities at all... (bc-injury-law.com)