I am writing this as I feel like lots of advice on foot function (meaning strength and flexibility) is overly complicated and ultimately aimed at selling something or proving how smart the dispenser of the advice is.
One thing I have learned is never assume anything about a client...TEST IT.
I had a fit client a few weeks ago who has had recurring calf issues for a couple years and asked me during a session if her feet might be weak or limited in some way. This gave me two options.
1. Go on a diatribe about the plight of modern footwear and how she needed to get back to nature and read three books on working the core muscles for her feet and...you get the idea
2. TEST IT
Turns out strength and mobility were fine and we resolved the issue quickly after with a minor equipment tweak and some pedaling technique advice.
If you want a whole list of the maladies of wearing shoes, go elsewhere. There are plenty of sensational things written on this. I'm not doing it. I want to put forth a few things I have found easy to check for yourself at home.
The basic idea here is to test ALL OF THESE and work on whatever you suck at. Easy, right?
I am listing them in the order that I think makes the most sense. Importance of each will depend on your particular goals and athletic pursuits.
NUMBER 1. TOE AND FOOT MOBILITY
NUMBER 2. ANKLE MOBILITY
NUMBER 3. TOE MOBILITY AND COORDINATION
NUMBER 4. SINGLE LEG CALF RAISES
*With these many people will have feet that are not in perfect alignment due to individual variation. Don't roll an ankle or anything but perfection isn't super important either. Hold on to something with your hand for balance.
I think the above tests are the main things to focus on.
If you are bad at one of them, well, I think working on that thing will help it!
Feet are stuck in shoes all day. It isn't a death sentence for them, but maybe not their perfect home either.
Let's make the best of it, yeah?