Toe Spring And Plantar Fasciitis

Ever wonder why so many people other than runners are getting plantar fasciitis? It may be because of the amount of 'toe spring' in your shoes.

You may have already noticed this in your running (or other) shoes, most of them seem to have 'toe spring'. Toe spring is how much the front of the shoe is curved upwards. This curve allows your foot to roll off the front of your foot more easily compared to wearing flatter soled shoes.

Hence, the toe spring allow your foot muscles to work less hard when you are walking or running. The more toe spring in the shoe, the less work your feet have to do.

However, this may lead to weaker foot muscles according to research (Sichting et al, 2020).Weaker intrinsic foot muscles may increase your chances of sustaining injuries like plantar fasciitis.

In the research which includes famed Harvard evolutionary biologist / barefoot running researcher, Daniel Lieberman, had subjects walk on a specially designed treadmill that had force plates and infrared cameras to measure how much power was put into each step.

The subjects walked barefoot in four different pairs of custom made sandals. The sandals had varying angles of toe spring from 10 to 40 degrees. These ranges of curvatures were designed to be similar to modern footwear.

Sandals were chosen as they allowed the researchers to see the exact motion of the subjects' feet as they walked. The different degrees of toe spring can be filmed to see how they affected their gait with special attention paid to the metatarsophalangeal (MTP) joints at the base of their toes. This is where the toe bones join to the foot bones.

The results showed that the more the shoes curved up front, the less propulsive force was generated with their MTP joints. This means that your intrinsic foot muscles are working less to maintain stability when you move making walking and running easier. However, it also decondition your foot muscles over time, making them weaker and not able to protect other structures in your foot.

Weaker intrinsic foot muscles make one more susceptible to conditions like plantar fasciitis as people rely on their plantar fascia to do what the intrinsic muscles normally do. This may also explain why people get injured if they transition too quickly minimalist type barefoot style running shoes.

Many of my patients who do not run with plantar fasciitis have been told to wear more 'supportive' and comfortable shoes while outside or even at home. This may be worse as their intrinsic foot muscles continue to weaken.

This is why shoes with more toe spring are popular because they are more comfortable and prevent your feet from tiring. This is great in a race and it may be why most racing shoes have a lot of toe spring (see picture below).

More research needs to be done with toe spring and foot injuries as other elements of footwear like stiffer soles and amount of cushioning can impact how our intrinsic foot muscles work.

So what should a runner do? Some physiotherapists and podiatrists often suggest doing intrinsic foot exercises like towel scrunching or pulling your toes toward your heel.

I suggest going barefoot more often. Either at the beach, or when you're at the playground with your kids. In Singapore we are generally barefoot while we're at home. That's better than wearing shoes with lots of toe spring at home. 

While training, look for running shoes with little or no toe spring when you train. 

For my patients who have plantar fasciitis, I tell them to wear flat slippers like Havaianas to minimize the effect of toe spring and for their intrinsic foot muscles to get stronger. 

That is totally different from what some other physiotherapists or podiatrists may suggest. Of course, I also treat plantar fasciitis differently from them.

Reference

Sichting F, Holowka NB, Hansen OB and Lieberman DE (2020). Effect Of The Upward Curvature Of Toe Springs On Walking Humans. Sci Reports 10, 14643. DOI: 10.1038/s441598-020-71247-9.

Asics Metaracer Tokyo - a racing shoe with lots of toe spring

Luna Mono Running Sandals Review

I've had the Luna Mono Mgt running sandals for a while now and feel ready to write about them after my most recent run in the rain. Despite being wet, the soles were truly non slip, I was truly impressed as I thought they'll be slippery but they were not at all.

Like I wrote before when I first received it, they were nice and soft to wear, almost no breaking in required compared to my other running sandals, the Earth runners huraches. They were also super light, great to bring them while traveling so they can double up as your running sandals.

With normal walking, I didn't mind the strap between my first web space (between big and second toe), but during the runs, I've had some minor discomfort and upon using normal or toe socks they went away.

Normal socks instead of toe socks

I found the "over the top" ankle strap very useful as it helped tighten the sandal to prevent my heel from slipping out (my right foot is slightly smaller than my left so I need to tighten the right sandal more).

I've even had my own version of running mini intervals with them. 3-4 times a week when I bring my two boys to the playground near our place I'll end up playing "big bad wolf" with most of the kids at the playground. I have to run hard to chase them and I must say the Lunas stay on my feet much better than my Havaianas slippers.

My calfs were a tiny bit sore the very first time I used them probably due to the fact they were new. I didn't have a problem with that thereafter.

The Luna Mono's have a fair ground feel and feel good to walk and run in. And they definitely don't give you black toenails. Thanks to Fred from Run Minimal  for the sandals.

Earth Runners Huraches/ Running Sandals Review

My Earth runners huraches

More than a year ago Mike Dally, founder of Earth Runners contacted me and asked if I was keen to review a pair of his earth sandals. I wrote back and said that I would be most happy to try a pair and mentioned that I live in Singapore.

Mike simply wrote back and asked for my size and mailing address. I requested for the Alpha X-11 mm which was a bit thicker and were more moldable. Mike added he was sending me the conductive leather laces.

The sandals were "zero drop" (same thickness between heel and the forefoot). There was a strap between the big and second toe and buckle on the outside the secure the sandal.

What was interesting was that I noticed there was a copper grounding insert flushed with the Vibram outsole. I later read that they were there to offer electrical conductivity  (or earthing). This is to offer the primal experience of walking/ running grounded to the earth. You can read more about the concept of earthing here. The copper inserts did not bother me at all while walking or running.

Copper inserts

I've waited a long time to write this as I wanted to wear the sandals in a bit before commenting. Mike Dally told me to take my time as most of the reviewers feedback was the longer they'd worn the sandals the more comfy they feel.

I first wore them mostly at home for up to a couple of hours at a time. I found that the leather straps (even though they were very soft) tend to cut into my first web space between my big and second toe. Because of this, I felt slightly more discomfort over the base of the second toe. Otherwise I had no issues at all with walking. The buckle at the side tightened without any difficulty at all.

I've began to wear them more recently as my older boy has been wanting to ride his bicycle. He can ride well but is afraid to stop as his feet can't touch the ground yet.

Lending a helping hand

So almost every single morning he's been asking to ride so I just wear my earth sandals with normal ankle socks and run alongside him steadying him when the need arises.

How does the sandal feel while running? If you've run in minimalist shoes, then you'll understand when I say they have a fair ground feel. They were nice to run in after you've broken them in and gotten used to them. They offer more than ample protection for the running that I do. If you have black toenails like me, then they will be very much appreciated since there's nothing for you to jam your toes against.

For the fashion conscious, hey look real cool with its raw genuine hurache appearance and you can wear them pretty much everywhere else.

Thanks Mike for a great pair of running sandals.