Shoe Cushion Trick

[Perry]

Thought I'd share a useful trick I've been doing for 15 years. It has likely saved my knees from thousands of feet of downhill running over the years.

I just order polyurethane foam from McMaster-Carr:
https://www.mcmaster.com/#poron-urethane-foam/=17wxon8
https://www.mcmaster.com/#86375k233/=17w8ynv
Then trace my insoles using a ball point pen, cut out with scissors, and replace or add underneath or on top of the original insoles. For myself, 1/8" medium is about right. 1/4" soft will absorb more impact and better protect the front and lateral side of the knee, at the expensive of more stress on the arch (plantar fascia) and more pronation which can stress the medial side of the knee I believe. There's also a higher risk of ankle sprains going with 1/4" soft.

It is less expensive than the medical-grade Poron used by podiatrists. It's very similar, just has an industrial smell instead of the added scents.

Very few shoes these days have polyurethane insoles or midsoles because EVA is cheaper, and there's usually not a business incentive to extend the life of shoes. The reverse may be true because if the shoes break down quickly, the consumer will come back again and buy shoes sooner.

[Perry]

A few years later, here's a DIY video:
https://www.youtube.com/watch?v=6Qu-U38iRmw

These days I'm using adhesive-backed foam and adding a thin rubber layer underneath. Links in description.

[Ed]

Perry,

What do you think of Spenco insoles? I've tried orthotics and expensive insoles you heat and mold. But drugstore Spenco insoles seem to work as well or better for me.

[Perry]

Hey Ed, I've only tried those about 2 decades ago, and they were just okay not great in terms of cushion or arch support. They might have new products now, but I think I've seen the same product. Neoprene-like foam full length with plastic 3/4 length support.

These days for walking and working I wear Copper Fit Balance (semi-rigid full length) for plantar fascia with 1/4" Poron underneath to protect against shin splints. I have a medium arch and normal pronation.

[Perry]

A couple tricks for plantar fasciitis:
https://www.youtube.com/watch?v=cGMX-TE6ZBY Kevlar fabric
https://www.youtube.com/watch?v=5PWt_EXBQfw nylon film

[Perry]

When I posted my Kevlar and nylon videos on a running science group there was skepticism and disinterest. A couple guys downvoted my Kevlar video. But I really think people will start putting Kevlar in insoles because a lot of shoe designs cause plantar fasciitis.

I ran some fast downhill on Saturday with Kevlar insoles. No plantar fascia problems, and I don't remember feeling any rocks poking through the thin shoes. Also got the Strava crown on one of the more competitive downhill segments in this area.
https://www.youtube.com/watch?v=XOTgpJQy8s4
https://www.strava.com/activities/5341603511

[Perry]

Here's the double-insole method for walking and working:
https://www.youtube.com/watch?v=BZ35MpqPdxo

And over the weekend I did a quick descent of the Museum Trail, only 11 seconds slower than the 2019 mountain running world champion:
https://www.strava.com/activities/5385193826
It wasn't the best choice of shoes, but I believe the nylon film insoles protected my arches.

Short version of my Shannon Trail descent with Kevlar insoles a week ago:
https://www.youtube.com/watch?v=x-COY4pJW1c

[Perry]

Museum Trail descent in about 6:33. Polyurethane + nylon insoles (30 mils).
https://www.youtube.com/watch?v=tZuU_jFAfxg
https://www.strava.com/activities/5458219594