Can a strap reduce hip internal rotation during running?

An increased hip internal rotation is known to be an associated risk factor for running associated injuries, such as patellofemoral pain or non-contact ACL injuries. Researchers in the USA designed a treatment device (‘the Powers strap') to facilitate an external rotation of the femur and thereby control abnormal hip and knee motion during leisure and sport activities. However, research that proves the effect of such a brace is lacking. Thus, this study aimed to investigate whether this device is able to modify hip rotation during the stance phase in running.

In total 22 healthy participants were asked to run at their own speed under 2 conditions: without and with the strap. 3-D motion analysis was conducted using 10 Qualisys OQUS 7 cameras and force was captured with 3 AMTI force plates. Paired sample t-tests were performed at the 95% confidence interval on hip and knee kinematic and kinetic data. The strap reduced the hip internal rotation angle on average 3 to 5 degrees during the stance phase in running. Also the knee internal rotation angle was significantly reduced, however the changes were small (2 degrees). No changes of the lower limb kinetics could be identified.

This study showed that the new device significantly reduced the hip and knee internal rotation angle throughout the stance phase and corrected the hip and knee rotation towards a neutral alignment. A reduction of the hip internal rotation during running has to date not been achieved with any other treatment approaches, such as running retraining, straps, braces or patellar tapes. Thus, the strap might be a promising treatment approach to treat patients with a symptomatic excessive hip internal rotation.

> From: Greuel et al., Gait Posture 57 (2017) 141-146. All rights reserved to Elsevier. Click here for the online summary.