OT non Newtonian Fluids

I bought a pair yesterday. I am not a skateboarder but this is interesting to me.

I mentioned them to my mother. I hope she gets a pair for her skeletal problems.

Just thought of @WendyBG these take out most of the impact on the feet and joints up the legs and beyond. Absorbing 90% of shock but leaving full control.

Click on a size and often a few color types will show up under the shoes.

The pads are also an interesting find.

The material was developed for NASA to place objects outside of the ISS that would possibly have collisions.

In one of the videos mid way through a plate of glass is put under two insoles. One of the insoles is FP’s, the other is a common insole. The glass breaks when something like a bowling bowl is dropped on the common insole. When the FP takes a turn the glass easily survives.

The skateboarders are just cool in their own way. This is their far and away number one choice of shoes.

The second test in this video is interesting. The reason the second test is importan the fp insole stops the force of landing on an object from the surface underneath. The behavior is non Newtonian and counter intuitive.


They look nice for normal feet, like I used to have up to about 5 years ago. Unfortunately, I tore the Posterior Tibial Tendon (PTT) – the tendon that wraps around under the inner ankle bone and holds up the arch of the foot – on both sides. I had to get custom-molded orthotics that cost $850. I also wear ankle braces and New Balance shoes. That doesn’t stop me from doing Zumba but I have to be very careful. If I tear those tendons again I might need surgery. They took a year to heal.

So I can’t wear generic orthotics even if they are very good. But thanks for thinking of me. :slight_smile:



There are a few flavors of the insoles. Some of them podiatrists compare to the much more expensive custom made orthotics. The reason you heat them up and they fully fit the foot.

But I can not make any recommendations to you. You have a very unique set of conditions. I’d be wrong to go there.


@WendyBG …when you say on both sides, do you mean both feet?

This is a timely post from @Leap1 as ligaments, tendons, muscle etc have been on my mind of late. It’s just over a year since I started my Road to Recovery rehab after lapiplasty surgery on my right foot and I’ve been repeating the treadmill training series I used to assess how far I’ve come over the year. I’m sure you’ll agree that patience is paramount when rehabbing ligaments and tendons…and that necessary patience can do a real number on associated muscles. Especially the fast twitch fibers.

By sheer coincidence…and a degree of irony…my Z2/MAF/low lactate/ASCVD mitigation training on the tread is accompanied by a Peter Attia podcast with a guest who’s area of interest is exactly this: training impact on preservation of fast twitch fibers. More specifically the impact of lack of training and the consrquences for healthy aging. I thought of you as you’ve had an injury that, like my lapiplasty, has probably provided you with insight into how rapidly these fast twitch fibers can be lost…especially among the Chronologically Enriched.

For example, the surgery (mid October '21) was pre planned so I did just over 3 months before that of a sort of supercompensation period to hopefully counter the inevitable bed rest and rehab time…more running, plyometrics etc and before the surgery could do a 12 inch box jump with no problem. I can currently barely manage to safely launch myself onto a step without the risers!! I wonder if it’s even feasible to gain that back…and what extra impact surgery on the other will have in the future when I’ll be even more grown up?

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It’s this one. Probably behind a paywall but, from some of the convo, Andy Gilpin uses social media a fair bit so might have stuff that’s more accessible for anyone intetested…


Can you give an update on the insoles in a month or so, as in did you notice a difference, and any negatives you found ?

I still do some hi-impact stuff, nothing crazy, but like to trail run
in the no-snow months, and these insoles might help.

( the dropping the bowling ball on them, with no bounce up, is a really good demo, the thought of that insole soaking up the force from every running step is intriguing )


Yeah I will. I just asked one of their chat people if it is a walking shoe. Part of my business is on a concrete floor. I also walk. It is not a running shoe. When we were kids we never assumed we’d use a running shoe to walk around. The Rockports are harder flat soles for walking. Supposedly they are slightly heavier.

I am waiting for a response from the chat on using them for walking. The company is three hours behind on the west coast.

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I’m reminded that ketchup is the usual example of a non-Newtonian fluid. When agitated it is shear thinning. Shaking the bottle makes it flow better.

Shear thickening is also possible but less common. Imagine turning on the mixer to stir a batter and having it solidify.

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Both ankles.

In 2017, I felt pain in my right ankle just below the medial ankle bone. I thought it was a slight muscle strain and continued to do Zumba as usual. BIG MISTAKE! Within 3 weeks, the tendon failed right under the ankle bone. I had Stage 2 PTTD. I couldn’t raise my heel even 1/4" and walked with a painful limpe. (The TMF computer won’t let me spell this word correctly.)

I didn’t know what the problem was but I was in a lot of pain. An X-ray showed that the bone wasn’t broken. My primary care didn’t know what it was. When I complained to my friends, the Facebook computer referred me to the PTTD support group. Very nice people.

The PTTD support group members posted X-rays of their surgeries. Multiple 2" (spiral fasteners – beware the TMF computer) embedded in their foot bones. PAIN!!

I decided I would do anything to avoid surgery. Orthotics, ankle brace, strong-sided shoes. Deep-water aerobic exercise 4 times per week. I did Zumba and HIIT seated in a chair, moving my legs vigorously but not touching the floor. Two tablespoons of collagen powder every day. It took a full year to heal.

Then, in 2020, I tried a physical therapy exercise, raising the heel to tiptoe. I was super-careful, holding a doorway with both hands. But my left PTT failed.

Since my father had “fallen arches” and my sister has totally flat feet with an accessory navicular, I can say with pretty good confidence that my PTT tendons are probably congenitally weak. But they were OK for decades. They just couldn’t take me dancing like a 25 year old in my 60s.



I would be interested to Leap, I have been running half marathons and with that have had calf, knee, and shin problems. Those might help soften the running. Keep us updated please.



Feet…Nature’s joke on Mankind for walking upright!

If there’s any way to avoid surgery, I’d give that route a try. I was so reluctant that I really left the decision for too long. By the time I bit the bullet, the difference was so great between before and after, it inevitably put more strain on the ligaments and tendons that an earlier reconstruction would’ve avoided.


Thank you for sharing this video which I intend to watch when I have more time (tomorrow).

I am just as interested in maintaining the fast response of my nervous system (neurons in the brain and nerve signals to the muscles) as I am in maintaining the fast-twitch muscles themselves. That’s why I think Zumba is superior to HIIT (which I also do).

Zumba requires the student to observe the teacher and quickly imitate fast-changing dance steps to music. HIIT moves are repetitive (as are many other types of exercise). Once your brain understands the move it’s 16X (or 100X) but the brain can go to sleep while the body exercises.

Try doing this Zumba warm-up. Focus and fast response are required continuously as the stress and balance move from one muscle group to another and side to side. Try it, and don’t neglect the hip movements which are so important for strengthening the lower back.



Group exercise in general is under-rated in this regard…following someone else’s directions, cues, timing etc whether you want to or not goes a long way towards what I used to call “brain training” when I was teaching. Folk could well understand the idea in, say, a boot camp class but always some who didn’t understand the assignment in SPIN.

Training seniors, fall prevention etc has become quite a niche market over the past decade or so and, as beneficial as the seated Silver Sneakers stereotypic class is to get folk started, dance, choreographed step, or senior boot camp etc are probably even more likely to keep a person out of the nursing home.

Although I’ve got a really extensive library of DVDs …both instructor training and stuff for the home exerciser … the subscriptions I maintain for my Peloton and Nordictrac/iFit combo along with the gym are worth what I pay and then some.

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I don’t see the point of a Peloton. I have a bike I got at WalMart, in the back room with a stereo, a TV, and a DVD player. I put on some tunes, or a DVD, to keep me distracted, while I pedal.

No need to pay big bux to ride the “bike of shame”


Well, I have that option too should I stop seeing the point of the Peloton platform. The rationale of using it (at least, the way I do working with power zones) is to stay engaged, not distracted…much the way that Wendy describes the value of Zumba. Mental as well as physical conditioning.


I spend most of my days, especially in the winter, reading and learning. Watching an old ep of “Enterprise” while I pedal, or “Hogan’s Heros” is about as much mental downtime as I have.

Example: Want to debate whether Captain Leach’s account of Hood being sunk is right or wrong? I can do that. I think Leach’s observations were correct. Today’s armchair admirals say it’s impossible, and construct elaborate golden BB scenarios to explain the ship going up like a Roman candle. But I read USN gunnery tables from 1935, and learned the trick to punching through the deck of a decrepit battlecruiser at that range. All it took to make that kill shot on Hood was Bismark’s gunners knowing their business.

For those who have no idea what I’m going on about, here’s a clip of a favorite of mine, cracking good story, and mostly true. Hood blows up around the 2:58 mark.

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So do I. But the neural networks that are exercised by pure brain work are different than the neural networks that are exercised by observing and reacting to our environment and physically responding to them quickly in real time with fast-reaction, constantly-changing body movements and shifts in balance.



@VeeEnn, yes! I have found over years that working out in a class with an instructor motivates me to work much harder than I work on my own. Those last few minutes and last few reps that are so hard – if the instructor is motivational and the other people in the class are doing it I force myself to go the extra time where I often slack off on my own.

That’s why I got a web cam. I do classes over Zoom with instructors I try to get to know personally. The social interaction is important to me. I even painted portraits and mailed them to the instructors. This instructor and I have become friendly. She messages me if I miss a class, which motivates me to come regularly.

My sister works out from videos but I find the personal interaction with a live person motivating.


That would be driving in the constant, heavy, traffic in metro Detroit, not to mention the day trips I take in the summer to destinations in Michigan and Indiana. I-94 is decidedly undersized, at two lanes, for the traffic that has built up over the last 60 years. MDOT has been scratching around in Jackson for years, requiring drivers to deal with repeated changes in the traffic pattern.

Has anyone done a study of retention of mental acuity wrt age, among people who drive a significant distance per year, vs those who do not?


Driving is a sedentary activity. You move your hands and feet by inches, no more. Your brain is exercised but your body is not.

Only dancing – and only dancing that requires split-second timing – has been demonstrated to reduce the risk of dementia.

Keep dancing… it turns out it is good for the brain

Picking up choreography can seem like a brain teaser. Interpreting which arm, which leg, which direction even, can lead to legs and arms everywhere except for the very position they should be in. This can be frustrating, but keep dancing, as research suggests that learning new steps could prevent dementia.

by Alanna Orpen , 4 Apr 2016, BMC Blog

The complex mental coordination that dance requires activates several brain regions: the cerebellum, the somatosensory cortex and the basal ganglia, triggering kinaesthetic, rational, musical, and emotional responses. This strengthens neural connections and can improve our memory…

In 2003, research published in the New England Journal of Medicine found that dancing can reduce the onset of dementia. The 21-year longitudinal study of senior citizens, aged 75 and older, was led by the Albert Einstein College of Medicine in New York City…

The researchers studied a range of cognitive and physical activities, such as reading; writing; doing crossword puzzles; playing cards; playing musical instruments; dancing; walking; tennis; swimming and golf. Surprisingly, dance was the one activity that was good for the mind, significantly reducing dementia risk. Regular dancing reduced the risk of dementia by 76%, twice as much as reading. Doing crossword puzzles at least four days a week reduced the risk by 47%, while cycling and swimming offered no benefit at all…

Neurologist Dr. Robert Katzman said, “Freestyle social dancing, such as foxtrot, waltz and swing, requires constant split-second, rapid-fire decision making, which is the key to maintaining intelligence because it forces your brain to regularly rewire its neural pathways, giving you greater cognitive reserve and increased complexity of neuronal synapses.”… [end quote]

The article didn’t mention balance but of course that is an important safety issue for elders. Zumba includes turns, walking backwards and box-step moves that require balance.

These moves all use large, four-limb motions since the arms are moving at the same time as the legs in large-muscle movements that require coordination.

Don’t kid yourself that driving stimulates the brain, nerves and muscles in the same way as Zumba.