Throwing is a very complex movement involving high rates of joint acceleration particularly through the shoulder joint. To generate this high rate of joint acceleration, one of the fundamental goals we are trying to achieve is a ‘tight turn’ through the axial skeleton by translating momentum from the foot to the hand.

In executing the ‘tight turn’, I want that momentum to be travelling in the direction of the target I am aiming for. The foot in this case, serves as the initiator and navigator of this direction of momentum. To be able to direct it effectively, the foot needs to be able to change into certain shapes through the throwing motion. To simplify the mechanics of the foot and required shapes needed through the throwing motions, I need to be able to apply pressure through the inside of my foot to direct momentum towards the intended target.

The mobility of your big toe is going to heavily influence the behaviour of your foot and the shapes it can attain. If I have a big toe which demonstrates limited extension, it is quite likely that flexor hallicus longus (big toe bender) is behaving in a concentric manner. 

In the image below, you’ll notice the black arrow pointing to a section of tendon of flexor hallicus longus that sits beneath a bony projection (sustentaculum tali) on a bone in your foot called talus. When pulled tight, this tendon effectively lifts up the bony projection and subsequently the inside of the midfoot; therefore to be able to apply pressure through the inside of my foot (midfoot in this circumstance), I need to been able to relax this region (with certain timing through the throwing motion). 

Limitation in big toe extension would suggest there is an inability for an individual to demonstrate this relaxation. As a result, there is now difficulty to apply pressure through the inside of the foot and therefore direct momentum towards the intended target. 

Let’s say in this instance I have a right handed thrower with inability to get inside foot contact with their right foot. As they go through the throwing motion pressure now runs through the outside of foot and the momentum we are generating is therefore heading to the right of the target we are aiming for.  If I want to redirect momentum to get it back in the direction of the intended target, I will have to twist heavily on a structure above the foot to do this. 

 

This is where I will potentially start to expose body regions to focal excessive stress and in this case potentially a shoulder. Strategies like heavy side bends through the torso, neck, knees diving in towards midline are all effective at redirecting momentum but may leave a thrower in a position where they hold the shoulder open.

An example is shown above, with the red arrow pointing to a focal extension/side bend through the torso which redirects momentum but also has the torso pushing faster forward than the shoulder and effectively leaves it behind and open exposing it to more focal loading.

 This is not the answer to everyone’s throwing shoulder pain but hopefully highlights that we can consider other factors if more direct treatments are not provided the intended outcomes.