These injuries are two of the most common overuse injuries in runners, and given that one prominent research paper found hip weakness to be linked to an increased overall risk for any running injury, scientists predicted that hip strength (or a lack thereof) would be linked to additional common running injuries.
Today, we’ll look at a pair of new studies which indicate that hip weakness and instability is implicated in causing medial tibial stress syndrome ( shin splints ), another extremely common running injury.
The latest studies
The pair of studies, released in February and October of this year, were published by a team of researchers based out of Ghent University in Belgium. Ruth Verrelst and the other researchers followed 86 women who were enrolled in physical education classes at the university.
The studies both used a prospective design, meaning they measured the biomechanical variables of interest at the beginning of the study. This is important, as it rules out any changes in mechanics that occur because of an injury. Thus, the subjects who would go on to develop medial tibial stress syndrome—shin splints—could be compared equally to those who did not.
The first of the two studies looked specifically at hip abductor and external rotator strength. By the time Verrelst et al. ran their statistical analysis, 21 of the women in the study had been diagnosed with shin splints by a doctor.
The subjects who got shin splints had significantly worse hip abduction strength at the beginning of the study, proving the use of hip strength testing in screening for shin splint risk.
Notably, external rotator strength was not found to be related to the risk of developing medial tibial stress syndrome.
The second study looked at biomechanical variables associated with hip stability as opposed to just hip strength. Work with runners who have biomechanically-linked knee pain has shown that measurements of hip muscle strength don’t always convey the whole picture—how your muscles actually function when working to stabilize your hip while running matters at least as much as raw strength ( in-depth lesson on this topic here ).
Unfortunately, this study didn’t specifically address runners; the hip stability tests Verrelst et al. conducted were based on a single-leg drop jump, a task which involves hopping down from a step and immediately hopping up again as high as possible. However, while not ideal, this study still has some relevance to running, as it’s effectively a simulation of one “step” of a running stride.
Regardless, using data prospectively collected from the same population of female physical education students in the first study, Verrelst et al. demonstrated that:
The women who developed shin splints had significantly more motion in their torso and hips when they landed and pushed off when compared to the women who stayed healthy during the study.
More specifically, this motion was localized to what’s termed the transverse plane, which encompasses lateral twisting movements of your chest and leg. This is of particular interest because the hip abductor muscles, which were found to be related to shin injury risk in the first study, are not primarily responsible for hip motion in the transverse plane.
As Verrelst et al. describe in their conclusion, there is still a lot more to be learned about the interplay between hip strength, pelvic stability, and injury risk. Why do abductor weakness and transverse plane instability predict injury risk, but not external rotator weakness or frontal plane instability?
Further, runners with a history of shin problems should strongly consider adding some hip strength exercises to their daily routine.
1. Prins, M. R.; van der Wurff, P., Females with patellofemoral pain syndrome have weak hip muscles: a systematic review. Australian Journal of Physiotherapy 2009,55, 9-15.
2. Fredericson, M.; Cookingham, C. L.; Chaudhari, A. M.; Dowdell, B. C.; Oestreicher, N.; Sahrmann, S. A., Hip Abductor Weakness in Distance Runners with Iliotibial Band Syndrome. Clinical Journal of Sports Medicine 2000, (10), 169-175.
3. Niemuth, P. E.; Johnson, R. J.; Myers, M. J.; Thieman, T. J., Hip Muscle Weakness and Overuse Injuries in Recreational Runners. Clinical Journal of Sports Medicine 2005, (15), 14-21.
4. Verrelst, R.; Willems, T. M.; De Clercq, D.; Roosen, P.; Goossens, L.; Witvrouw, E., The role of hip abductor and external rotator muscle strength in the development of exertional medial tibial pain: a prospective study British Journal of Sports Medicine 2013.
5. Verrelst, R.; De Clercq, D.; Vanrenterghem, J.; Willems, T. M., The role of proximal dynamic joint stability in the development of exertional medial tibial pain- a prospective study. British Journal of Sports Medicine 2013,0, 1-7.
6. Souza, R. B.; Powers, C. M., Differences in hip kinematics muscle strength and muscle activation between subjects with and without patellofemoral pain. Journal of Orthopaedic & Sports Physical Therapy 2009,39 (1), 12-19.