Sacroiliac Joint Pain in Crossfit
Anatomy of the SI Joint
The sacroiliac joint is a large joint that connects the sacrum (tailbone) and the ilium (hip bone). It is a very stable joint with strong ligaments and muscles surrounding the joint. There is a small amount of rotation that occurs in the SI joint during movements involving the spine, pelvis, and hips. Although there is movement in the SI joint, its mean purpose is to transfer forces from the lower body to the upper body and vice versa.
Even though SI joint dysfunction is a common term used to described this pain syndrome, the joint is rarely "out of alignment." The large ligaments and muscles that support the joint make it quite a robust joint.
Cause of SI joint pain
As you might imagine, there is a lot of load that is transferred through the SI joint. While it is a very strong joint, too much load on the SI joint can cause irritation and pain in the joint. The increased load either through intensity or duration of load irritates the tissues between the sacrum and ilium leading to pain.
In Crossfit athletes, the dynamic movements of rowing and burpees along with the heavy loading in squats and deadlifts can be a recipe for SI joint irritation and pain. The research reports that a squat with 27 pounds would produce about 6.5 kN (1461 pounds of force) to the SI joint. Since Crossfit athletes typically lift more than 27 pounds, it is safe to say that the loads placed on the SI joint are much more.
SI joint pain treatment
Most cases of SI joint pain can be treated conservatively. The initial treatment approach is to decrease irritation and pain through joint manipulation and soft tissue work to the surrounding muscles. Often it is necessary to temporarily reduce the load SI joint to reduce irritation and compression to the joint.
Once the irritation to the joint has calmed down, a progressive strengthening program can help reduce the loads placed on the SI joint. The strengthening program usually focuses on the glute muscles around the SI joint but should also include core and other lower body muscles that may have contributed to the injury.