The SI (sacroiliac) joint is the joint in the pelvis that connects the lower body to the torso and acts as a transfer station that absorbs and distributes forces from the ground up, and from the upper body downward.
The SI joint is a stabilizing joint with very limited mobility. Stability is provided to the SI joint by large muscle groups in the lower back, glutes, and hamstrings, as well as a vastly complex web of ligaments. Sacroiliac joint dysfunction is a common cause of low back pain, and is thought to be the most common cause of it in professional dancers. Dancers sacrifice stability at the SI joint for increased range of motion, making them more susceptible to injury.
Weakness in the gluteal muscles is often a contributing factor to SI joint dysfunction which can then lead to tightness in the hamstrings due to overcompensation. Because the SI joint is such an integral connection between the trunk of the body and the lower extremities, pain and dysfunction in this area can cause numerous problems in the lower back, hips, and knees.
Additionally, since there are so many large muscle group connections in this area it is highly innervated, making it more sensitive to pain and causing increased frequency of referred pain, often in the glutes, hips, and groin area.
Treatment for SI joint dysfunction should include heat, stretching, and progressive corrective exercise over a 4-6 week period:
Week 1: Apply heat to lower back for 15 minutes then proceed with passive stretching in a non-weight bearing position (i.e lying on your back.) Stretching should include knees to chest, right and left trunk rotation with knees bent, straight-leg raise, and single-leg internal and external rotation. Stretches should be performed 3 times per week, with each stretch held for 30 seconds.
Week 2: Apply heat to lower back for 15 minutes then proceed with the same passive stretching exercises from week 1. Begin incorporating stretches such as supine hip flexion/external rotation, quadruped lumbar flexion/extension (aka Cat/Cow stretch), and prone cobra stretches. Passive stretches should be held for 30 seconds, while active stretches should be performed in 3 sets of 10 reps 3 times per week.
Week 3 & 4: Apply heat to lower back for 15 minutes. Begin with stretches from week 1 & 2. Strength training should begin with resistance band exercises in a non-weight bearing position, such as: straight-leg raises with a resistance band, side-lying abduction/adduction, and hip extension in quadruped position. Exercises should be performed in 3 sets of 10 reps 3 times per week.
Week 5 & 6: Apply heat to lower back for 15 minutes and proceed to active stretching. Begin to incorporate low-impact, weight bearing corrective exercises such as squats, walking lunges, walking high knees, and standing single-leg hip adduction/abduction and extension with weight cables. Perform each exercise in 3 sets of 10 reps 3 times per week.
Acute SI joint dysfunction often occurs due to muscle strain or trauma and should respond well to these exercises. However, chronic dysfunction results from muscle imbalances and compensatory movement patterns due to poor ergonomics, and therefore these exercises will only serve as a temporary solution if poor postural habits are not corrected.