Hip abductor weakness in distance runners with iliotibial band syndrome

Objective: To examine hip abductor strength in long-distance runners with i liotibial band syndrome (ITBS), comparing their injured-limb strength to th eir nonaffected limb and to the limbs of a control group of healthy long-di stance runners; and to determine whether correction of strength deficits in the hip abductors of the affected runners through a rehabilitation program correlates with a successful return to running. Design: Case series. Setting: Stanford University Sports Medicine Clinics. Participants: 24 distance runners with ITBS (14 female, 10 male) were rando mly selected from patients presenting to our Runners' Injury Clinic with hi story and physical examination findings typical for ITBS. The control group of 30 distance runners (14 females, 16 males) were randomly selected from the Stanford University Cross-Country and Track teams. Main Outcome Measures: Group differences in hip abductor strength, as measu red by torque generated, were analyzed using separate two-tailed t-tests be tween the injured limb, noninjured limb, and the noninjured limbs of the co ntrol group. Prerehabilitation hip abductor torque for the injured runners was then compared with postrehabilitation torque after a 6-week rehabilitat ion program. Results: Hip abductor torque was measured with the Nicholas Manual Muscle T ester (kg), and normalized for differences in height and weight among subje cts to units of percent body weight times height (%BWh). Average prerehabil itation hip abductor torque of the injured females was 7.82%BWh versus 9.82 %BWh for their noninjured limb and 10.19%BWh for the control group of femal e runners. Average prerehabilitation hip abductor torque of the injured mal es was 6.86%BWh versus 8.62%BWh for their noninjured limb and 9.73%BWh for the control group of male runners. All prerehabilitation group differences were statistically significant at the p < 0.05 level. The injured runners w ere then enrolled in a 6-week standardized rehabilitation protocol with spe cial attention directed to strengthening the gluteus medius. After rehabili tation, the females demonstrated an average increase in hip abductor torque of 34.9% in the injured limb, and the males an average increase of 51.4%. After 6 weeks of rehabilitation, 22 of 24 athletes were pain free with all exercises and able to return to running, and at 6-months: follow-up there w ere no reports of recurrence. Conclusions: Long distance runners with ITBS have weaker hip abduction stre ngth in the affected leg compared with their unaffected leg and unaffected long-distance runners. Additionally, symptom improvement with a successful return to the preinjury training program parallels improvement in hip abduc tor strength.