The Obturator Internus (OI) is a deep gluteal muscle, which can cause pain that is often confused with hamstring pain. For pain either side of the ischial tuberosity (sit bone) a soft tissue technique called ART is effective in treating.
Patients with deep gluteal pain near the ischial tuberosity are often told they have a high hamstring strain. Often the hamstring is not involved, but the obturator internus or the sac beneath it called a bursa is. About 20 different bursae have been identified near the hip and pelvis(1). A bursitis under the OI should always be considered.
..the obturator internus tendon makes a right-angled bend over the grooved surface of the ischium, between the ischial spine and tuberosity, and then passes horizontally across the posterior to the hip joint before it inserts into the greater trochanter. Moreover, the obturator internus bursa is located between the obturator internus tendon and the grooved surface of the ischium(1) (anatomy video).
A bursa can get irritated and become inflamed (bursitis). If tendinopathy is suspected but bursitis is also possible, it is wise to do exercises that load the tendon without compressing the bursa against the bone underneath it. Avoiding compression of tendons where they pass over bones during loading is covered in this video.
Obturator internus EMG amplitude was greatest during hip extension, then external rotation then abduction, with minimal to no activation in other directions (2)
Therefore to shorten the OI, the thigh goes backward, rotates outward and is moved away from the body. Once the muscle is shortened and it is contracted against resistance the tendon will be loaded without extra pressure on the bursae.
1. Check hip range of motion.
2. Activate the core with planks and recheck the hip.
4. Prescribe exercises which maintain good hip function.
Articles I wrote or contributed to:
Telegraph The ART of Active Release Techniques for Injuries
STACK New Age of Golf Training is Creating Stronger and More Athletic Golfers
Athletics Weekly Performance Therapy for Greg Rutherford
220 Triathlon ART- How is it different from sports massage
Vigour Magazine ART can release tight muscles to improve performance
Progenex ART for CrossFitters
FIT Institute Research based hamstring therapies
TPI What Performance Therapy Looks Like For Top Golfers