Every year or so I'll end up with plantar fasciitis after periods of time where I've walked a lot. In general my walking shoes are fine and have arch support but occasionally I'll need to use sturdier boots or sometimes walking sandals with no support. It's usually not long after that that the pain starts.
What methods or items of equipment are there to prevent this? Are there good quality shoes/boots/sandals with arch support? Does anyone have experience of extended walks with inserts?
If there was a magic solution to preventing plantar fasciitis, then no one would have it anymore! Different things work for different people. It's important to find out what works for you. This can be done with experimentation or the help of a specialist.
One thing I would caution against is just throwing more padding at it! There is something wrong with your stride and the padding may hide it for while, but it will eventually come back. I say pay particular attention to how you're walking while wearing your walking shoes that do not give you any problems. Then walk around in your sandals or your boots. Pay attention to how your feet land in the different footwear, and how you transition to your next stride.
Find the stride that works best for you and practice it. I know it's strange to have to think about walking again, it's supposed to be something we just do, but I find it helps me.
When I'm hiking with my thin soled trail running shoes, I have a tendency to step and land on the front of my foot and I take quicker, smaller steps. While in heavy boots, I'm definitely a heel striker with longer strides.
Plantar fasciitis is a degenerative (not inflammatory) repetitive stress injury (RSI). Studies using radioactive tracers have shown that the rate of tissue replacement in connective tissues is often extremely slow, maybe even zero. Therefore these injuries can be extremely slow to heal, and in some cases the microscopic damage is simply permanent. So you really want to avoid injuring these tissues in the first place, and the basic prevention is not to do too high a level of activity.
Although people usually feel PF as heel pain, the damage is actually in the webbing that makes up the arch of the foot, which only happens to have a point of attachment at the heel. You just don't have nerve endings in the main body of the plantar fascia. Therefore the issue isn't really heel strikes or lack of padding in the heels of your shoes. It's just an over-use injury involving the natural use of the whole foot. Plantar fasciitis is correlated with obesity and with standing up while working, but that's probably not so relevant here.
There are many treatments that have been promoted for PF, but the scientific evidence for almost all of them is weak. There is no evidence to support massage, stretching, taping, therapeutic ultrasound, or modifying the patient's stride.
Orthotics are the one treatment that is reasonably well supported by research. Custom orthotics are no better than cheap off-the-shelf ones. The idea that they correct problems with mechanical alignment is empirically false. Many podiatrists believe that choosing the right orthotic is important, and that they know how to do it; evidence doesn't support this. Orthotics provide an improvement in function that lasts for a few months. They do not give any statistically significant reduction of pain. After 12 months, they're no better than a sham treatment consisting of an orthotic made of soft, thin foam.
Sources:
Injury Series: Plantar fasciitis in runners as a degenerative overuse injury
Treat Me, but No Tricks Please
Close Look at Orthotics Raises a Welter of Doubts
Effect of Shoe Inserts on Kinematics, Center of Pressure, and Leg Joint Moments during Running
With plantar fasciitis, weight is a big causal factor. If you think you could loose a few pounds, that might help your feet too. Pack weight is also a big deal. Buy a balance that measures in grams, and then start weighing everything you carry. Weigh your knife, food, cellphone, empty bottle, empty bag, even your underwear. Put all that into an excel spreadsheet and it will be simple to start slashing those pounds.
You also want to reduce the shock when your feet hit the ground. The mass of your shoes is important. Use that balance and weigh all of the shoes you have. In general, your heel strike will be more forceful in heavy shoes. Try getting some trail running boots for when you need something sturdy. These can be a third the mass of traditional day hike boots, and they are usually more comfortable anyways.
Paying attention to your gait is a great idea. Watch some videos on gait pathology to get an idea of what is and is not normal. The knee should be flexing ever so slightly during the loading phase. Speaking with a medical professional is also a good idea.
