Floppy Feet Syndrome

A deep dive on floppy feet

Picture this:

You’re an elite race car driver on par with the likes of Dale Earnhardt, Jeff Gordon, and Ricky Bobby.

You spend an ungodly amount of time and money souping up the engine. You make sure the frame is aerodynamic and the body looks sleek…

… then you throw some partially deflated discount tires on it.

How fast do you think you’re actually going to go on race day?

You can have all the horsepower in the world, but if your tires can’t transfer that force to the ground efficiently, you’ll still be slow and out of control.

That’s exactly what happens to athletes with “floppy feet.”

Like tires, your feet are the interface between your body and the ground. If that interface is weak and inefficient, then it doesn’t matter how strong your quads, glutes, and hamstrings are. You’ll never maximize your sprinting potential.

If you want to sprint fast and jump high, your foot needs to put as much force into the ground as possible and put that force into the ground as fast as possible.

There are two ways our body can put force into the ground:

1. Elastic recoils
2. Muscle contractions

Let’s talk nerdy.

Elastic Recoil

Achilles tendons are elastic structures. Think of them like rubber bands.

If you stretch a rubber band out then release it, it shoots forward. If you stretch a thicker rubber band out the same amount, then it shoots forward with more power.

The component that makes the thicker rubber band fire out with more power is stiffness.

Stiffness is a dirty word to the general public, but that’s just because it’s misunderstood. To get more explosive, we actually want to increase your tendon stiffness.

To make this make a little more sense, let’s look at the Stress-Strain Curve.

• The y-axis shows how much force the tendon is being pulled with (stress).
• The x-axis shows the amount the tendon stretches out (strain).
• The slope of the line represents the how much the tendon resists being stretched out (stiffness).

The green tendon is stiffer than the blue tendon. With the same force pulling each tendon, the green tendon stretches less than the blue tendon.

If the tendons are stretched to the same length, the stiffer tendon will recoil with greater force.

Here’s how that whole story plays out in your foot.

When your achilles tendon is stretched as your foot hits the ground, it stores elastic potential energy. When it recoils back into shape, it converts that potential energy into kinetic energy, which can actually be used to propel us forward.

If your achilles tendon stiffness increases, two things can happen:

1. Your tendon will stretch to the same length as it did previously, but it’s increased stiffness will allow it to recoil harder and put more force into the ground each step.
2. Your tendon will stretch to a shorter length, but it’s increased stiffness will allow it to recoil with the same force that it used to. The shorter stretch will happen faster, which means you can get off the ground faster with each step.

Both of these situations (more force applied and shorter ground contact times) lead to you sprinting faster.

The best way to improve tendon stiffness is through heavy loading. We’ll dive deeper into that later.

Muscle Strength

At the hip, the muscles do most of the work and are the main movers of the joint. At the foot and ankle, though, the muscles main role is to hold shape to allow the elastic structures to do their thing.

The foot and ankle are loaded with muscles. The most practical way to evaluate their function and train them is through groups.

The calf muscles must anchor the top of the achilles in place, to allow the bottom of the achilles to stretch as the foot hits the ground. If the calf muscles aren’t strong enough to hold steady, then no stretch happens, as both ends of the achilles just shift downwards.

The midfoot muscles act to hold the the integrity of the arch of your foot.

The forefoot/big toe muscles stabilize the last link between your body and the ground. All of the force that you built up must travel efficiently all the way through this tiny area.

Muscle “stiffness” (isometric strength at these really high speeds) is best improved with plyometrics and isolated strengthening.

Put it All Together

If we put it all together, the interventions we need to use are: 1) heavy load strength work, 2) plyometrics, and 3) mobility*.

I put together an example 16-week program that maps out how you can progressively cover all of these bases. It can be found here: ​​​Ankle_Foot Stiffness 16 Week Program.pdf​

Here’s how each component part shows up in the example program:​​

1. Strength:
   • Calf/achilles: calf raise variations
   • Midfoot: foot bridge variations
   • Forefoot/big toe: toe presses
2. Plyometrics:
   • Intensive plyos: sprints and jumps
   • Extensive plyos: pogos
3. Mobility
   • Ankle dorsiflexion: bent leg (KAD) and straight leg (SLAD) mob
   • Big toe extension: BTE mob

*Mobility isn’t always necessary. If you have enough ankle dorsiflexion from bent/straight leg positions and enough big toe extension, there’s no need to chase more. Just make sure you don’t lose those positions as you layer on stiffness.

Some additional common questions…

Wait, so you want me to be stiff and have enough range of motion?

Yes. I know it sounds paradoxical, but our tendons are low-key magical.

The magic is called “viscoelasticity.” The stiffness of our tendons can actually change based on the speed at which the force is provided.

Long, slow forces result in our tendons having lower stiffness, so they can get into more positions. Quick, fast forces result in our tendons having higher force, so we can spring off the ground rapidly.

I heard I have to do isometrics to improve tendon stiffness, is that true?

Isometrics are good, but not necessary. The type of contraction (eccentric, concentric, or isometric) doesn’t matter. Tendons are noncontractile. All they can do is sense load.

It doesn’t matter how the load gets there, it just matters that it does.

How about shoes?

When it comes to training, I like to take a barbell approach to footwear. You should either wear super supportive shoes or no shoes at all. Avoid the middle area.

If you’re doing aggressive sprint, jump, and change of direction work, you should wear your supportive sport shoes with good traction (cleats, basketball shoes, volleyball shoes, turf shoes, etc.). This allows your foot to safely and effectively put a huge amount of force into the ground quickly.

If you’re doing activation drills, light plyos, or strength work, you should take your shoes off. This allows your foot to move through its full range of motion, be exposed to different sensory inputs, and experience low-intensity, long-duration strength work to stabilize itself.

A quick thought on a podcast all baseball/softball parents need to listen to.

Eric Cressey is the Director of Player Health and Performance for the New York Yankees. He recently released a podcast covering 7 reasons why young athletes don’t make long-term progress.

He’s a baseball guy, but the lessons apply to all sports.

Please listen to it. You can find it ​here​.

A couple of important things…

1. This newsletter is completely free. I spend many hours each week researching, writing, and illustrating (okay, maybe the drawings don’t take that long). The best way you can support it and allow it continue is to share it with people you know. You can just send them to ​gtperformance.co​ and they can subscribe there!
2. Everything in these newsletters and on our website is for educational purposes only and should not be taken as medical advice for you or your athlete. Consult directly with a healthcare professional.

Thanks so much for your help in spreading the word about athlete development!

Be >,

Zach

Dr. Zach Guiser, PT, DPT, CSCS