They might be. Research has shown that people with sacroiliac joint pain often have problems with urinary frequency (having to urinate often) and urinary incontinence (inability to control the bladder). One reason for this may be the way the muscles around the bladder work with other muscles to form a force field.
A healthy force field gives strength to the structures holding the bladder in place. At the same time, the pressure within the abdomen increases from these muscles contracting. This helps support the low back and sacroiliac joint.
Whenever someone develops problems with urinary function, a doctor should be consulted. Once the physician rules out the possibility of a more serious problem, such as pressure on the nerves to the bladder, the condition of the muscles can be evaluated. A nurse or physical therapist with training in urinary or bladder problems can help you retrain these important muscles.