Want to get a grip? Then grab a pair of the most popular kind of minimalist shoes, flip-flops, and put them on your feet. Now walk, and feel the flexors of your ankles and toes grip, literally. Meet your flexor digitorum longus. Entombed deep to the gastrocnemius and soleus in the lower leg, the flexor digitorum longus flexes the second through fifth toes, inverts the foot, and aids in plantar flexion of the ankle.

If the FDL is constantly working to keep your flip flop on your foot, it can get irritated quickly.

If the FDL is constantly working to keep your flip flop on your foot, it can get irritated quickly.

Originating in the middle of the posterior surface of the tibia and traveling down the leg inserting in the distal phalanges of the second through fifth toes, the flexor digitorum longus (FDL) is one of three ankle and toes flexors. Along with the tibialis posterior and the flexor halluces longus (FHL), the other foot flexors, this narrow muscle is a primary player in tiptoeing, navigating rocky trails and picking up small objects off the floor with the toes.

When wearing loose fitting flip type shoes that do not connect to your foot, the FDL has to work extra hard, along with the FHL, to hold the shoe in place so you don’t flop, I mean fall. The gripping of the FDL can result in a change in normal dorsiflexion during the swing phase of the gait cycle. The over-emphasized flexing action on the bottom of the foot can have detrimental effects on the gait cycle of the sandal wearer. It can lead to pain in the heel, in the metatarsophalangeal and interphalangeal joints, in the plantar fascia, and may also cause discomfort up the anterior and lateral side of the lower leg, reaching all the way up through the IT band. Mainly, as we are focusing on the flexor digitorum longus, this slim muscle has to do a heck of a lot of overtime when the action of toe flexion is called upon so intensely.

Though the warmer months are rapidly approaching, switch out the flip-flops for footwear that connects to your feet and save your flexor digitorum longus for hiking in the woods, walking barefoot in the rain, and for some of your favorite standing balanced yoga poses like Half Moon and Tree Pose. Get a real grip and ditch the flips!

Read more on the negative side effects of flip flops

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Laurie Streff

Laurie is a movement educator with over 25 years of fitness teaching, management, and corporate wellness experience. Passionate about creating learning spaces that are innovative, dynamic, and every-body friendly, it's Laurie’s goal to inspire people to prioritize self-care through exploratory movement and restorative techniques. She is especially excited to share the self-care principles of Yoga Tune Up® and The Roll Model® Method which bring heightened awareness to what the body needs to operate at its very best. Laurie teaches a wide variety of classes at Equinox clubs in the Los Angeles area, and also provides movement workshops, teacher trainings, and corporate wellness sessions nationwide.

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I appreciate the anatomy lesson in why our feet feel so sore after long periods of wearing flip flops. Normally I limit use of flips to wearing to the yoga studio or the pool, but after this lesson I’m questioning this decision. Thank you for the reminder to take care of our feet!

Cat Fur

Do Fit flops also cause problems? They feel so supportive and are one of the few shoes I can wear for any length of time without pain.

Charlene Lowe

You just made my spring cleaning easier. The cheap flip flops are going to charity or garbage. Since becoming a yoga teacher and spending more time in barefeet, I wear something more supportive like birkenstocks. My toes are still grabbing but overall my feet are happier.