Optimizing Sports Performance From the Ground Up
Foot Strengthening For Athletes
By: Phil Loomis
Everyone loves their shoes! Many folks are devoted enthusiasts of a certain brand. Others want to make a fashion statement with their kicks and some just need to wear something that’s comfortable. As performance coaches, there’s no doubt we love our footwear and the athletes we coach are no different.
That said, it’s easy to overlook the feet sometimes because they are encased in the latest shoe innovation. But when we take those shoes off and look down at our feet what do we see?
Is it a lifeless club? Can you even feel your feet? Are your toes scrunched together? Does your forefoot flare out? Is there a rather disproportionate concave bulge near the medial subtalar joint/inner ankle?
Sometimes looking at an athlete’s bare feet can you tell you a lot.
I was a little overwhelmed with where to start because there is SO MUCH, I believe coaches need to be aware of with regard to not only the structure of the foot/ankle complex but primarily its function.
The foot/ankle complex in most cases is the only point of contact with the ground. It must act as both mobile adaptor and spring-like lever within the same movement.[i] There is a fine line between mobility and stability and a finely tuned sensorimotor system is vital for optimization of gait. Motor input dictates motor output, whether it’s optimal or not is what we need to explore.
Ron Hruska of the Postural Restoration Institute (PRI) has noted that the non-manual techniques (corrective exercises) utilized by PRI take place with the feet grounded on a wall/floor. Hruska says to “plant it, sense it.” The plantar surface of our feet is wired for pressure and perturbation which allows us to innately sense the position of our joints/body.
Hruska also describes the foot as a transducer. A concept that in my mind has untapped and significant implications for performance/movement coaches. A transducer is something that converts a signal in one form of energy to a signal in another, like an antenna.
The feet act as sensory receivers that transduce information from the floor/ground up to the brain stem. Hruska also described the plantar surface of the feet as preceptors (in Latin this means warned) that provide feedforward information. Without this warning the afferent input is skewed and we lose variability (eversion, inversion, supination, pronation…) or the aforementioned mobile adaptor function.
The following is an excellent example from Dr. Evan Osar on how this warning signal can be skewed and lead to biomechanical compensation.
The goal during the loading of the foot is to spread the metatarsals in order to create a reflexive response and optimally load the first ray of the foot. If this motion is blocked by a rigid arch foot, an orthotic insert, or a shoe with relatively stiff instep (to prevent excessive pronation), the nervous system will recognize this and make compensations to help improve the medial loading and metatarsal spreading of the foot. One common way is to drive the knee through the frontal plane into a more valgus position to help load the medial aspect of the foot. [ii] – Dr. Evan Osar
If the foot can’t pull in the information it needs, due to, in this case, a structural block, our neuromuscular system will attempt to pull that information from another source. A source that is not ideally suited to do so because it lacks the anticipatory potential of the foot.
At an NSCA conference Dr. Emily Splichal (an authority on the foot/ankle complex) described the small nerve proprioceptors in the plantar skin and fascia as having the potential to be anticipatory. While the large nerve proprioceptors such as the Golgi tendon organs and the muscle spindles are much slower and more reactive in nature.
I think we can all agree that the loading strategy described above by Dr. Osar would is non-optimal. If knee valgus (in this case) is the athlete’s preferred strategy to medially load the foot, it was a reactionary response initiated after the warning from the small nerve proprioceptors was blocked.
As coaches we need to develop strategies to ensure that athletes are not neglecting the power of this anticipatory/feedforward function of the foot/ankle complex.
Before we can optimally develop these strategies however, there are a few key concepts that need to be highlighted.
Muscle Tuning Theory
Dr. Benno Nigg proposed the muscle tuning theory in the Clinical Journal of Sports Medicine in 2001. Nigg stated the following:
Impact forces (from running) are input signals that produce muscle tuning shortly before the next contact with the ground to minimize soft tissue vibration and/or reduce joint and tendon loading.
Nigg followed up his research in the Journal of Biomechanical Engineering with the implications of an un-tuned landing.
The subjects: 13 male runners exposed to three different environments; expected soft, unexpected hard and expected hard landings.
For the unexpected landing there was no muscle adaptation, as subjects did not know the running surface was going to change. In support of the muscle-tuning concept an increase in the soft tissue acceleration did occur.
Practically speaking it takes a few steps for the muscles to become tuned to a surface. Once the body tunes to that surface, anticipatory muscle tuning occurs to dampen soft tissue vibration and decrease joint and tendon loading.
If the surface suddenly changes it can’t be anticipated and the muscles can’t match the frequency of the incoming vibrations and there is a sudden increase in joint and tendon loading.
In 1993 I remember watching a Chicago Bears versus Philadelphia Eagles game at Veterans Stadium (The Vet). Chicago wide receiver Wendell Davis ran a pass pattern and pulled up to make an attempt on an under thrown pass, no contact both ACLs ruptured!
The Vet was old school Astroturf, basically a layer of fake grass on top of concrete/cement.
According to Dr. Splichal:
Unlike softer ground surfaces like grass, gravel or dirt, hard, artificial surfaces like cement, aren’t good at absorbing force. When the foot strikes a hard surface like cement, the vibrations actually rebound and double up back into the body.
This is why moving on hard surfaces is so hard on the body. Hard surfaces create more stress and fatigue on the connective tissues and bones and contribute towards injury.
Purely speculative on my part but it’s possible that Wendell Davis’ muscles could not tune to the surface and the sudden impact force when his feet hit the ground lead to joint and tendon loading that exceeded the threshold his passive structures could resist.
Think of all the non-contact injuries sustained on artificial turf surfaces where the athlete goes down in a heap as if taken down by the dreaded turf monster! Add to that stiff football shoes and possible ankle taping that locks the foot/ankle up and simply doesn’t allow the athlete to sense and feel the ground.
In Michigan during the winter boots are a necessity. My boots are stiff and immobile and I can’t even feel my feet. If I feel compelled to run after the dog or take evasive action in a snow ball fight, I feel extremely uncoordinated as my foot/ankle are rendered useless due to the structure/rigidity of the boots.
Many athletes compete in this large nerve proprioceptive environment which is very reactionary in nature (versus anticipatory). It’s really a testament to their athleticism/conditioning that injury rates are not higher.
As a follow-up to this last point let’s talk about what happens when we put our shoes on…
Shoes: Friend or Foe?
In her webinar titled: The Role of Barefoot Science and the Shod Athlete Dr. Emily Splichal states that when we put on our shoes we enter a large nerve (reactive) response environment. As previously mentioned, this large nerve environment is not fast enough to dissipate impact forces. We need to tap into that small nerve (anticipatory) response environment. We need to be barefoot to optimize this environment.
That said, it’s simply not practical to participate in sport without shoes so let’s throw that notion out entirely.
Fortunately, there are things we can do even with our shoes on to facilitate these small nerve responses.
A study by Waddington et al., looked at subjects’ discrimination between different extents of inversion at the ankle with socks on, barefoot, shoes/socks on, and textured insoles with no socks. They concluded that across the 36 weeks of the study, movement discrimination scores for the barefoot condition showed significant improvement.
They also concluded: the addition of textured insoles to the shoes was found to restore movement discrimination back to barefoot levels.
In this case discrimination is good, it means better positional awareness.
Another study by Waddington et al., used 17 elite female soccer players under 3 conditions their own football boot, bare feet, and own football boot with textured insoles. Their results showed; Movement discrimination scores were significantly worse when subjects wore their football boots and socks, compared with barefoot data collected at the same time. The substitution of textured insoles for conventional smooth insoles in the football boots was found to restore movement discrimination to barefoot levels.
They therefore concluded that; the insole is one aspect of football boot and sport shoe design that could be modified to provide the sensory feedback needed for accurate foot positioning.
Steinberg et al., 2016 also concluded that; the stimulation to the proprioceptive system arising from textured insoles worn for five weeks was sufficient to improve the proprioceptive ability and performance ability of ballet dancers.
So, it seems a nice bridge from barefoot training to sport/competition shoes would be a training shoe with a textured insole.
Practical Strategies for Narrowing the Gap between Barefoot and Competition Footwear
Step 1 Train in a small nerve/barefoot environment
Janda et al., stated that Short Foot Exercise (SFE) improved the position of body segments and the stability of the body in the standing position by increasing afferent inputs from the bottom of the foot. They also stated that SFE is the first step in sensory motor training (proprioceptive training) and can improve proprioception and postural stability if applied along with other exercises.[iii]
Short foot is a tremendous strategy for activating the intrinsic muscles of the foot. So how do you execute a short foot?
Soysa et al., stated that flexion at the metatarsophalangeal joint and extension at the interphalangeal joint, is an action hypothesized to activate the foot intrinsic muscles. This group also noted that allowing a toe-curling action to occur is an action associated with the contraction of extrinsic foot muscles. In other words, don’t curl your toes if you want to activate the foot intrinsics!
Dr. Emily Splichal’s points of emphasis when coaching short foot:
- One foot at a time
- Working leg knee slightly flexed
- Establish a foot tripod (expertly explained here by Dr. Evan Osar)
- Spread the digits
- Engage the pelvic floor
- Root the tips of the digits to the ground
- Hold for 10 seconds
Short Foot Demo
A few passive strategies that may allow athletes to more optimally execute short foot.
Per point number 4 above, spreading the digits. Think about athletes that have their feet crammed into athletic shoes (especially those that practice/play with stiff cleats that often have a narrow toe box) for several hours each day. If you have athletes take their shoes and socks off to have a look at their bare feet, then you will often see toes that are quite literally “glued” together. In some cases the toes will even cross over. Why is this a big deal?
According to Sue Falsone:
Compressing the toes will lead to pointing the first ray in a more medial position, often creating a bunion. When we have a bunion, we do not properly transfer force from the rear foot to the fore foot; we “fall through” the midfoot, further driving the compensation. Repositioning the first ray is imperative in restoring proper foot function. Once we restore this range of motion, the short muscles of the foot have room to do their job, allowing activation and strengthening of the important proprioceptive muscles. [iv]
Falsone states one of the best techniques she has found for repositioning the first ray is the use of toe spreaders. She recommends starting with 5 minutes daily working up to 30 minutes. I ask athletes to wear them at home while doing homework and to keep a pair in their gear bag for road trips.
Another strategy is working on the suppleness of the plantar surface. The best strategy here is rolling the bottom of your foot over a ball. Start with a less stiff ball such as a tennis ball. Then, work toward a lacrosse ball and even a golf ball. Move slowly along the foot tripod and avoid curling/crunching the toes. Imagine spreading the foot wide and keeping the toes long. Initially the pressure can be quite uncomfortable and athletes will tend to “grip” the foot. When the foot is suppler it can better serve its “mobile adaptor” function. This is critical for absorbing ground reactions forces.
To take the short foot activities to the next level we need to move to single leg stance.
According to Dr. Splichal when we move to single leg stance, we activate the Lateral Line. The glute medius is part of the Lateral Line.
Sue Falsone states:
If you activate the glute med, the foot intrinsics will fire and create a short foot. Glute med activation and foot function go hand in hand. [v]
How do you know if the athlete’s glute med activates in single leg stance?
Dr. Splichal states that when an athlete transitions to single leg stance you should see the subtalar joint move from relative eversion to a more neutral alignment via inversion. If the subtalar joint is “stuck” in eversion we need to get the foot talking to the hips.
Here are a few activities that can help open the lines of communication between the foot intrinsics and the glute med in a less demanding position than single leg stance.
Side Lying knee toward knee
Standing AF IR w/Short Foot
Step 2 Textured Insoles
The research looks very promising with athletes that use textured insoles to improve proprioceptive ability and performance ability.
The one caveat though is it appears the best way to do this is to use them without socks or a very thin sock. The whole idea behind the insoles is for the plantar surface to “connect” with the textured surface of the insole. Most socks are definitely going to interfere with the ability of the plantar surface to sense and feel that textured surface. You could try putting the insoles in your socks but having personally tried this it doesn’t work that well.
My recommendation is to have a pair of designated training shoes to use them in without socks. I have used them with ground-based warm-up exercises and “controlled” movement training like skipping, crawling, single leg stability exercises and lunge variations. I have also used them when performing primary (squat, hinge, push, pull, etc.) and accessory strength training patterns.
Step 3 play your sport/compete!
Finally, it’s time to hit the floor/court/ice! Suit up as normal and compete in your normal footwear and socks. Dr. Splichal states that if you train in that small nerve environment (barefoot) and use textured insoles during training there will be a carryover to gameday! That said, it’s not magic! You have to consistently train this way to make that carryover reliable and sustainable. Not only that, but Dr. Splichal made what I thought was a very profound statement. She told me that wearing the textured insoles not only during training but also in casual shoes (in addition of course to barefoot love and care) is a form of recovery. Your feet get banged up when they are locked up in stiff and often poorly fit athletic shoes. Therefore, you can reap huge dividends if you take care of your feet after the game or practice.
Summary:
Our feet are often out of sight but that shouldn’t hide their true potential. As coaches we need to implement strategies that will allow our athletes to harness and refine the ability of the foot/ankle complex to sense and feel the ground. In turn, this will help them move more efficiently.
Other considerations:
If an athlete can’t get over their big toe (hallux dorsiflexion), then their glutes will be restricted in their ability to extend the hip (closed chain).
Surface science
As mentioned previously hard surfaces are hard on the body! Minimize an athlete’s exposure to surfaces like cement, black top, marble, and turf fields. This is especially true for those built upon previous structures like parking lots).
So, what surfaces are the best to train on?
Dr. Splichal says natural surfaces are best for optimizing muscle tuning and thus reducing soft tissue and connective tissue stress. Surfaces like dirt, real grass, and wood flooring particularly the type in dance studios. Some areas may even have tuned running tracks.
Foot wear
Make sure the shoes fit! A few years ago at an event called Pitchapalooza, Dr. Allen Sills (now chief medical officer for the NFL) gave a fascinating presentation on a pilot study his group had done with 7 NFL teams (well over 200 players involved):
Almost 50% of players will have one size difference between the left and right feet.
There were vast disparities in the length and width of a size 12 from different manufacturers, up to 2 full sizes.
In some cases, the same manufacturer had different models in the same size that were up to 2 sizes different.
91% of the athletes involved were rolling/falling off the edge of the shoe/foot plate.
Sills provided the following tips:
- Most athletes have no idea the “true” size they need (get them fitted properly).
- At least 50% will have one size difference between left and right (make sure both feet are measured).
- The style of the shoe is just as important as the size (different positional requirements).
Better fit=better interaction with the surface=less risk of injury and better force transfer from the ground up.
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[i] ” Chapter 26 The athletic foot and ankle.” Sports Injury Prevention and Rehabilitation, by David Joyce and Daniel Lewindon, Routledge, 2016, pp. 346
[ii] ” Chapter 4 The Hip Complex.” Corrective Exercise Solutions to Common Hip and Shoulder Dysfunction, by Evan Osar, Lotus, 2012, pp. 103.
[iii] Janda V, VaVrova M: Sensory motor stimulation. In: Liebenson C (Ed.), Rehabilitation of the Spine. Baltimore: Williams & Wilkins, 1996, pp 319–328.
[iv] “Chapter 7 Somatosensory Control.” Bridging the Gap from Rehab to Performance, by Sue Falsone and Mark Verstegen, On Target Publications, 2018, pp. 166-167.
[v] “Chapter 7 Somatosensory Control.” Bridging the Gap from Rehab to Performance, by Sue Falsone and Mark Verstegen, On Target Publications, 2018, pp. 168.
About the Author:
Coach Phil Loomis is a fitness professional and nutrition coach at Life Time Athletic in Bloomfield, MI as well as a strength and conditioning coach for the Michigan Red Sox in Birmingham, MI. He was also the head coach and CEO of Forever Fit in Troy, MI. He is currently certified as a Strength and Conditioning Specialist, Youth Athletic Development Specialist, and a Speed and Agility Specialist. Coach Loomis is also a Corrective Exercise Specialist, and a Precision Nutrition Certified Coach among others.
Coach Loomis played Division 1 college baseball. It was then that he developed the appreciation for the impact that off-field performance training and nutrition can have for developing athletes. His passion for youth and sports performance lead him to start Forever Fit. His training experience has lead him to develop a deep appreciation for corrective exercise and long-term athletic development strategies. He specializes in functional anatomy and bio-mechanics as they relate to program design and corrective exercise; youth athletic development; and rotational/overhead athlete performance enhancement.
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