
If the FDL is constantly working to keep your flip flop on your foot, it can become irritated quickly.
by Laurie Streff Kostman
Summer and warmer months of the year means it’s finally time to break out the flip flops! But did you know that wearing loose fitting flip type shoes that do not connect to your foot such as sandals or slides causes gripping and clenching in the muscles of the feet?
You may not even be familiar with the gripping that the flexors of your ankles and toes have to do to keep sandals on. Don’t believe me? Try running or walking in sandals without gripping with your big toe. Most of the grip work is handled by a slim muscle called the flexor digitorum longus (FDL).
Entombed deep to the calf muscles in the lower leg, the FDL is responsible for flexing the second through fifth toes, inverting the foot, and aiding in plantar flexion of the ankle. This narrow muscle is also a primary player in tiptoeing, navigating rocky trails and picking up small objects off the floor with the toes.
The gripping and over-emphasized flexing action of the FDL while wearing sandals can lead to pain in the heel, the joints of the toes, the plantar fascia, and may also cause discomfort up the front and side of the lower leg, potentially reaching all the way up through the IT band. It can even result in detrimental effects on how you walk, as motion in the ankle can be affected by over clenching on the underside of the foot.

The FDL can remain in a gripping position after prolonged and regular wear of sandals and slides.
The upside to warmer summer months is that we also spend more time barefoot, which is good news for the bones, muscles and tendons in our feet. After a long winter of toe constriction from tight fitting shoes, the muscles and tendons that support your feet need flexibility and strengthening exercises to prepare them for barefoot walking. If you already are a flip flop lover, it’s just as important to invest dedicated time in spreading the metatarsals (the 5 long toe bones) of the feet as they are often also compressed in cramped toe boxes of shoes or over worked in sandals and slides.
In preparation for putting your best barefoot forward (sans a flip flop), try rolling a Yoga Tune Up Therapy Ball or tennis ball on the bottom of the feet to revive the FDL and activate the other muscles surrounding it. Using a back-and-forth stripping action, roll the balls from the heel to the ball of the foot. This encourages widening of the metatarsals and much needed increase in blood flow to the plantar fascia area, which runs along the underside of the FDL. Whether you are a first time flopper or have a lifetime of FDL gripping under your belt, alleviating the tension on the underside of your feet will help to improve the overall health of the foot.
For movement, try my favorite the following Toe Separation Exercise below. These are terrific techniques for flip-flop feet as the gripping muscles of all five toes will be especially happy with some this restorative attention.
So switch out the flip-flops for footwear that connects to your feet and save your FDL for the good stuff, like hiking in the woods, walking barefoot in the rain, and your favorite balance poses like Half Moon and Tree Pose. Get a real grip and ditch the flips!
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Laurie Streff Kostman is a movement specialist with over 25 years of fitness training, management, and corporate wellness experience. A passionate fitness instructor who has earned UCLA, ACSM, AFAA, and numerous other fitness certifications throughout her career, it is her more recent completions of RYT-200 from White Lotus and Yoga Tune Up certified instructor trainings that have had the most impact on her unique teaching style. Focused on creating exercise experiences that are innovative, dynamic and every-body friendly, Laurie’s goal is to inspire people to prioritize self-care through movement and restorative exploration.
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Earlier…
- Yoga for the Back to School ‘Blahs’
- Utkatasana (Chair Pose): What’s It Doing For You?
- Hitchhike Your Way to Pain-Free Shoulders
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Only 313 days until summer! Thanks YogaDork!
This makes me sad … I wear flip flops just about every day, but it fully explains the foot pain I’ve been having lately. I thought it was my walking shoes, but I guess not. I’ll be doing my foot flexing regularly so I can keep wearing flip flops. It’s a San Diego staple!!!!
I think its funny there is an advertisement for flipflops to the left of this article !
I agree with some of what Laurie writes, but it also needs to be taken into consideration that not all flip-flops were created equal. Yes, if you just go to Old Navy and get one of their cheapo plastic flip-flops, then yes I would agree with all of the above. However, there have been many innovations in flip-flops that provide greater support of the foot that I would far rather see a student of mine wear than many of these over padded and cushioned sneakers out there. Not all flip-flops are evil for the feet…and some people need to open their feet up more anyway!
There’s too many people in flip flops. I live in South Florida and that’s all you see. That and barefeet. Show some class