Well, how convenient. A fantastic picture for teaching from the cover of one of our favorite magazines.
For this post, lets start with the gal on the left in the pink shirt. 1st of all, she is running in flip flops. Since these require so much long flexor activity to keep them on, not the best footwear choice, in our opinion. Check out that exaggerated left sided arm swing. This goes to propel herself forward. Why the extra effort? Check out her right (stance phase leg). What do you see? The knee points outward while the foot is planted. We are looking at either external tibial torsion or a femoral retrotorsion. Did you pick up the compensatory head tilt to the left? The vestibular system has become involved, and the trapezius and levator scapula seem to be it’s target (thus the shoulder hike and ipsilateral rotation), as well as the ipsilateral lateral benders and rotators of the cervical spine, namely the splenius cervicis and capitis (the multifidus/rotatores are contralateral rotators).
How about the subtle pelvic shift to the right? and the mild crossover gait (note the adduction of the left knee across midline).
It would be great to see a shot of her barefoot to see what changes, as increased long flexor activity has both local (impaired ankle rocker, excessive forefoot inversion, reciprocal inhibition of the anterior compartment muscles of the lower leg) as well as long distance (namely increased flexor drive to the brainstem and cerebellum) implications. We would want to see this (as well as examine her) before making any recommendations other than LOSE THE FLIP FLOPS GIRLFRIEND.
Wow, all that and we have only scratched the surface.
We remain the geeks of gait: Ivo and Shawn