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The Importance of Foot Intrinsics - How to Potentially Decrease Your Chance of Injury by 2.5 Times

Updated: Jan 15

Up to 80% of runners get injured every year - crazy right? Ideally, there are things we could do to lower our chances of developing an injury. What if I am consistent with a stretching routine? What about a general warmup or cooldown? What if I wear a certain type of shoe?


Unfortunately, all of these things have been studied and so far there is nothing to suggest that doing one of them will lead to a decreased likelihood of injury.


But what if I told you there IS something that you could do to decrease your chance of developing a running-related injury (RRI) this year by almost 2.5 times?


Well here’s some good news from 2020! This is exactly what the results of a new study by Taddei et al (2020) have found. They found an exercise routine that decreases runners chances of developing a running-related injury (RRI) by a factor of 2.42.

WHAT IS THIS ROUTINE, YOU SAY?


First, let’s talk about the methods of this study (what they did). This was a randomized controlled trial, where about half of the participants (61) were randomly put into a control group. 57 participants were placed in the intervention group.


The control group focused on stretching the feet with weekly guidance from a physical therapist. This was performed 3 times per week for a year, with testing performed periodically throughout and detailed tracking of injuries.


The intervention group performed foot and ankle strengthening exercises 3-4 times per week with weekly guidance from a physical therapist regarding the progression of strength exercises. They were also tested and tracked for injuries throughout the year.


Over the 12 months, 20 of the 61 runners in the control group developed a RRI. Only 8 of the 57 in the intervention group went on to develop a RRI - enough of a difference to be considered statistically significant.


The study suggests that 4-8 months of strength training is required to start seeing a protective effect against injuries.


This is pretty neat stuff!!

The Exercises


The list was long, which is unfortunate because previous studies have found 3-5 exercises to be a sweet spot for adherence to a home program.

  1. Plantar foot massage with thumb and ball on floor

  2. Toe manipulation (spinning toes like a screw)

  3. Feet tapping (heel fixed, as fast as possible)

  4. Double leg heel raise

  5. Invert/evert asymmetric

  6. Foot abduction (band resisted)

  7. Toe and ankle flexion (sitting, band around forefoot)

  8. Grab and hold squeeze ball/pen

  9. Squeeze toe spreaders

  10. Squeeze ball with little toes

  11. Toe abduction/adduction

  12. Short-foot

  13. Plantar arch raise

  14. 1-5 toe alternate (toe yoga)

  15. Toes grasping gait

  16. Toes abducted gait


Whew! That’s a lot. How do we make this list shorter and more realistic to perform on a regular basis?


The study found that the more the foot’s strength improved, the longer it took to develop a RRI. So I hypothesize that we can extrapolate that info and get rid of numbers 1-5 on the above list, as those are mostly geared toward mobility and activation - not strength.


The rest of the exercises on the list are great, and I prescribe most of them frequently. However, since coming across the Moboboard about a year ago I have found it to be more effective at improving foot intrinsic strength and overall stability of the foot. It is also more likely to increase compliance with a program as it is easy to do!

The Moboboard


(Use the code CULLENBERG10 for 10% off)


The Moboboard was created by one of the world’s leading running physical therapists and researchers, Jay Dicharry. He is the author of 2 outstanding books: Anatomy for Runners, and Running Rewired. I’d highly recommend anything Jay creates!!


How does it work?


The Moboboard is different from other balance boards in 2 main ways.

  1. The board tilts in a pronation/supination axis - which is actually how your body moves when you are running and walking.

  2. There is a cutout underneath your small toes (2-5).


What is the purpose of the cutout?


This is the main reason I like the board.


Many healthcare professionals will prescribe “foot” exercises to include things like towel curls and marble pickups. I did my first year out of PT school - that was what we learned! These exercises are using your long toe flexors - which are not foot intrinsic muscles and do not significantly contribute to the stability of the arch and foot. These muscles actually start way up in your calf, making them extrinsic foot muscles.


Intrinsic foot muscles are those that start and end within the foot itself. They contribute significantly to the stability of the foot and arch.


The Moboboard does not allow you to curl your toes - making foot intrinsic activation automatic! It forces your body to adapt a better stability strategy, pushing into the surface underneath your big toe. This is where 85% of the stability of our feet comes from.


If you’ve got a board, you can perform any single-leg exercise on it! They also have a great library of more exercises you can perform on the board if you need some ideas.

Who should get a Moboboard and/or be working on their foot intrinsic strength?


Short answer: every runner looking to avoid injury.


Longer answer: one of the limitations of the previously mentioned study was the size of n, or the total number of participants. Within the study, there were not enough running-related injuries that occurred over the 12 months to statistically be able to say which RRIs the foot strengthening program would best help prevent (foot injuries versus knee injuries, etc.).


The researchers suggest further research with larger populations, to see if there are specific body parts or injuries that the foot program can help prevent.


However, they did note that while there were some stress fractures that developed in the control group, NONE of the 57 participants in the intervention group went on to develop a stress fracture that year. I note this significance as stress fractures are certainly the most devastating of all RRI’s, in terms of the amount of time you have to take off from running.

Tripod Stance


Lastly, be sure to check out the following video we made about how to perform Tripod Stance. You should be incorporating it into your single-leg exercises! Tripod stance is a key way to ensure foot intrinsic activation if you don’t have a Moboboard - rather than relying on the extrinsic toe flexors for stability. We also show a demonstration of the Moboboard at the end!



Taddei UT, Matias AB, Duarte M, Sacco ICN. Foot Core Training to Prevent Running-Related Injuries: A Survival Analysis of a Single-Blind, Randomized Controlled Trial. The American Journal of Sports Medicine. 2020;48(14):3610-3619. doi:10.1177/0363546520969205


Go strengthen those feet!

-Kelton


Dr. Kelton Cullenberg, PT, DPT

Cullenberg Physical Therapy and Performance

@cullenbergpt

cullenbergpt.com