Responding to email questions: Why flat feet runners get shin splins?
December 5, 2014
One explanation could be TMTS (Too Much Too Soon) syndrome, which are very common with flat feet runners attempting to train a race. With that being said, as I mentioned earlier, the two principle components of foot function are the motions of pronation/eversion and supination/inversion. These two mechanical components are the ankle's ying and yang. Although a recent 2010 study suggests that flat feet may not be a factor in the development of TA related injuries (1), I find the relationship between flat foot syndrome and shin splints closely linked. But first let me tell y'all what I know about shin splint. It is an injury/pain resulting from overload to the anterior chain muscles of the lower leg, primarily anterior and posterior tibialis. These muscles are responsible for decelerating dorsiflexion (tibialis posterior), plantar flexion (tibialis anterior) and pronation (both of them). Now in my case, I over supinate which means both anterior and posterior tibialis are inhibited (weak) in proportional ratio to my gastros. When I walk, my right foot tends to supinate/invert during the swing phase right before heel strike. And BAMM, when this happens, you can see me from a 100 yards, breaking down and screaming like a little girl in pain. I am a rare case, but flattest feet runners (depending on the degree) usually over pronate. Pronation/eversion is the typical motion of the foot at heel strike - conducted by plantar flexion/abduction (tibialis anterior) and dorsiflexion (tibialis posterior) of the calcaneus. Over pronating will typically result in excessive sheer force to the tendons and ligament on the medial side of the ankle. Consider looking at your athlete's gluteus medius (hip abductor) and a lack of ankle dorsiflexion (tight calf muscles) when observing over-pronation of the ankle during the gait cycle.
1) Qaqish J, McLean S. Foot type and tibialis anterior muscle activity during the stance phase of gait: A pilot study. International Journal of Physiotherapy and Rehabilitation. 2010 Sep 15 [last modified: 2013 Apr 15]. Edition 1. http://ijptr.com/article/foot-type-and-tibialis-anterior-muscle-activity-during-the-stance-phase-of-gait-a-pilot-study/#sthash.z5h9lZbM.dpuf