I had an interesting debate today with two guys I really respect for their knowledge and passion about the body and fitness. It centered around what we would describe as "shin splints". One opinion was shin splints were more on the medial border of the tibia while the other opinion was more central shin pain in the anterior tibialis.
I think the key to shin splints muscle pain can be mid tarsal joint. The anterior tib inserts onto the medial cuneiform and first ray, much like the peroneus longus which runs down the lateral malleolus rather than the medial molleolus that the anterior tib inhabits. When the fore foot smashes into the ground it will invert and lengthen these muscles. If the supination process does not happen effectively the forefoot will not evert and lock up and these muscles will stay loaded throughout the propulsion phase leading to pain. This would be a similar scenario to why plantar fascia pain can occur.
One thing to check is the big toe. By lifting the toe up when weight bearing we can check to see if the arch will rise giving an indication of if the foot will become a rigid structure ready for propulsion. A manual inversion of the rear foot and eversion of the forefoot will also give an indication of the foots ability to lock up for propulsion.
Foot type and the individual flexibility in the foot can affect the propulsion process. If we had a valgus forefoot for example, as the forefoot hits the ground it will be unstable due to the lateral border being unsupported by the ground. An approach by the foot maybe to supinate early during midstance, however the foot will then be unstable on the lateral border leading to a pronatory compensation from the STJ at toe off or propulsion. This disruption in the foot sequence leads to an unlocked foot meaning an added lengthening load to the anterior tib and subsequent shin pain. An osseous restriction of the forefoot such as a valgus will also affect big toe function reducing the dorsi flexion of the first ray and the locking up of the foot.
Another topic of conversation was transverse plane motion at the STJ during the front foot phase of gait (I know, what geeks right!!!). Some people describe motion at the calcaneus as adduction. My opinion is however that most motion in the transverse and sagittal plane is blocked by the ground and therefore the plantar flexion and adduction of the talus will create relative abduction and dorsi flexion at the joint. This would be a case of the proximal segment moving faster than distal!! This talar motion now means the navicular portion of the talonavicular or mid tarsal joint will be abducting!! What fun we had!! Really a pointless piece of knowledge but a good reasoning process.
I have had a great response to my AFS/functional assessment process weekend in April so places are limited. Email me at [email protected] if you are interested. We will be looking at how to understand the assessment process better and applying knowledge as discussed in these blogs. After the success of the sports specific course in January I am planning another one in June. Please let me know if you are interested!!