November 2016

ITBS intrigue: Fatigue leads to decreased hip adduction

In the moment: Running

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By Katie Bell

Women with iliotibial band syndrome (ITBS) independently modify their running gait when fatigued to decrease hip adduction, potentially as a result of pain, according to research from Rutgers University in Newark, NJ, that may have implications for gait retraining.

The findings underscore the complex relationship between ITBS and hip adduction; some studies have reported excessive hip adduction in runners with ITBS, while others have not (see “Iliotibial band syndrome and running mechanics,” July 2015, page 35).

“I think the most important take-home message from these data is that there is no ‘recipe’ that can be given for gait retraining with a specific diagnosis,” said first author Allison Brown, PT, PhD, an assistant professor in the Department of Rehabilitation and Movement Sciences at Rutgers Biomedical and Health Sciences. “Prior to implementing gait retraining as an intervention, clinicians should evaluate the patient’s gait to see what gait impairments are present.”

The study included 32 female runners, 12 with ITBS and 20 uninjured. Overground running data were collected before and after participants performed a treadmill run to fatigue. The variables of interest were focused on stance phase: peak hip adduction and internal rotation angles, peak hip abduction and external rotation moments, and frontal-sagittal plane hip and knee joint coupling.

In the runners with ITBS, fatigue was associated with a mean peak hip adduction angle that was 3° smaller than in the uninjured runners, which translated to an 18.5% difference between the groups. There were no between-group differences with respect to hip adduction prior to the fatiguing protocol.

With respect to the remaining variables, fatigue did not affect injured runners differently than controls, and hip joint coupling did not differ between the groups during the loading or propulsive phases of stance. The findings were published in the November issue of Clinical Biomechanics.

Runners may minimize hip adduction to reduce pain by shortening the length of the
iliotibial band, the authors hypo­th­esized, noting that the other variables examined may not have been sensitive to such compensations.

Brown said that the participants had a mean pain level of .25 out of 10 on the Borg CR10 scale at the start of the run and finished with a mean pain level of 2.7, while two runners terminated their run due to their pain level reaching 6 out of 10.

“This pain may in fact be associated with the findings of the study, in that runners might have already adopted pathologic gait mechanics due to the pain. However, that would be speculation, as it was not tested,” Brown added.

Although the study did not look at other factors that have been reported to be associated with ITBS, such as narrow step width and knee internal rotation, Brown suggested rearfoot angle at initial contact and the rate of pronation should be considered.

“Most certainly the ‘endur­ance’ of muscles, rather than just their gross strength, should be considered,” she added.

Commenting on the study, Stacey A. Meardon, PT, PhD, an assistant professor in the Department of Physical Therapy at East Carolina University in Greenville, NC, said that it continues to be relevant to address excessive hip adduction, as it has been linked prospectively with ITBS and is positively associated with ITB strain rate.

Other factors that may be associated with ITBS under fatigue conditions include running-related characteristics, such as magnitude, frequency, duration, and intensity, Meardon noted.

“The specific relationship between prolonged running and potential for injury from a mechanistic viewpoint is likely related to stress accumulation without adequate recovery or adaptation,” she added.

The Rutgers investigators concluded that, since runners with ITBS decrease their stance phase hip adduction angles as a result of fatigue, management of this population should include screening for increased hip adduction prior to initiating gait retraining interventions.

However, stance phase hip internal rotation, coupling of hip adduction and hip internal rotation, and coupling of hip adduction and knee internal rotation are less likely to be associated with fatigue-related symptoms and therefore do not warrant a clinician’s focus when rehabilitating runners with ITBS.

Source:

Brown AM, Zifchock RA, Hillstrom HJ, et al. The effects of fatigue on lower extremity kinematics, kinetics and joint coupling in symptomatic female runners with iliotibial band syndrome. Clin Biomech 2016;39:84-90.

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