Take off your socks and stand in front of a mirror, and for some people the area just below the inner ankle bone bulges outward while the inner arch behind it looks completely flattened against the floor. Stand or walk for a while and a dull ache or tugging pain often runs along that tendon line, from just behind the inner ankle bone toward the top of the foot, and the inner edge of the shoe tends to wear out unusually fast. If you've spent weeks doing toe-curl or towel-scrunch exercises and the arch hasn't budged, the problem probably isn't that you did the exercise wrong, it's that the exercise was never aimed at the right muscle in the first place.
Curling the toes mostly works the small intrinsic muscles on the sole of the foot. The force that actually suspends the arch, though, comes from a long muscle that starts deep in the inner calf, runs behind the inner ankle bone, and attaches to the midfoot bones: the tibialis posterior. When this muscle's tendon stretches or weakens, the result is called posterior tibial tendon dysfunction, widely considered the most common cause of adult-acquired flatfoot. So this guide skips the toes and goes straight to the tibialis posterior with three exercises: resisted inversion with a resistance band, an inversion-emphasis heel raise, and a no-equipment foot-to-foot resistance drill, laid out stage by stage. If you're also curious about training the forefoot intrinsics, this companion piece is worth reading: towel scrunch foot arch exercise
If the area under your inner ankle bone feels unusually stiff after you take your shoes off at the end of the day, or your inner foot stings on the way down the stairs the day after a long walk, that muscle may already be worn out from carrying you all day. This pattern shows up especially often in women over 40, people whose jobs keep them on their feet for long stretches, and anyone who's put on weight recently, and left unaddressed it can progress to the rear foot rolling further outward, sometimes spreading into knee or hip pain. Starting muscle-specific strengthening at this stage is the most realistic way to avoid ending up needing orthotics or surgery down the line. The three exercises below need no special equipment, and following the sequence for about 6 weeks is designed to let you check your own level-up criteria and raise the intensity as you go.
Why Toe Exercises Aren't Enough: The Real Muscle Holding Your Arch
Why Toe Exercises Aren't Enough: The Real Muscle Holding Your Arch
The tibialis posterior starts in the deep layer behind the shin bone, wraps around just behind the inner ankle bone like a pulley, and fans out to attach broadly across the navicular and several other bones on the inner foot. Because of this path, it naturally pulls the foot slightly inward the instant the foot lands during walking, while also pulling the arch upward from above so the midfoot doesn't collapse too far. If the toe-curling intrinsics are a short strut holding up the front of the arch, the tibialis posterior is closer to a long cable suspending the whole arch.
Clinically, one common way to check whether this tendon is functioning well is to look at the foot from behind. If more toes than expected show up on the outside when viewed from behind, that's often called the too-many-toes sign, read as a signal that the rear foot is rotating outward while the arch collapses inward. If the heel fails to rotate inward, or doesn't lift at all, during a single-leg heel raise, that indicates the tibialis posterior has weakened considerably.
Looking at the gait cycle makes the muscle's role even clearer. From the instant the heel strikes the ground until the whole sole makes contact, the tibialis posterior naturally lengthens to absorb the impact of the leg moving forward, an eccentric contraction that controls the speed of that collapse. When this control loosens, the foot spends more time collapsing inward than it should, and repeating that over 6,000 or 10,000 steps a day adds up to considerable cumulative load on the tendon. That's exactly why strengthening reduces pain, it increases the total load the tendon can tolerate. Many people whose pain didn't settle with stretching alone actually needed this kind of load-capacity-building strength work first, not more lengthening.
Kulig and colleagues (2009, Physical Therapy) ran a randomized controlled trial in patients with early-stage posterior tibial tendon dysfunction, comparing a group using orthoses alone against a group that combined orthoses with resistive inversion exercise. They reported that the group who added resistance training showed a clearly larger improvement on the Foot Function Index than the orthoses-only group. That said, follow-up lasted only about 4 months and the sample was around 50 participants, so the trial doesn't tell us much about long-term changes in arch shape.
There's also research on how far nonsurgical management can go. Alvarez and colleagues (2006, Foot & Ankle International) applied an 8-week structured nonoperative program combining eccentric strengthening with custom orthoses to patients with early- and mid-stage posterior tibial tendon dysfunction, and reported that the large majority avoided progressing to surgery and managed their symptoms successfully. This was an observational study at a single center with no comparison group, and success was partly judged by the treating clinicians, so the result shouldn't be generalized to every patient without caution. Even so, both studies point in the same direction: resistance exercise loading the tibialis posterior directly contributes more to restoring arch-support function than stretching or toe exercises alone.
To get a rough read on where you stand right now, check these two things in front of a mirror.
| Check | Normal Response | Warning Sign |
|---|---|---|
| Stand barefoot, check toe count from behind | Almost no toes visible on the outside | Two or more toes visible beside the little toe |
| Single-leg heel raise | Heel rotates smoothly inward as it rises | Heel stays put, or pain prevents lifting it at all |
If either check comes back as a warning sign, or if the pain is severe or the arch has recently felt like it's dropping suddenly, see an orthopedic specialist before starting the exercises below.
Posterior tibial tendon dysfunction is usually described in stages. Early stage means the tendon has stretched but the arch shape still returns to normal when pushed by hand, a flexible state. Left to progress further, it moves into a mid stage where the arch stays low even while sitting, and it no longer springs back. In the late stage, the rear foot joints themselves deform and won't move even when pushed. This guide's exercises are designed for the early and mid stages, where the tendon still has some flexibility, meaning the arch shape returns at least partway when lifted by hand or the toes. If pushing on the arch doesn't change its shape at all, imaging and an orthopedic evaluation should come before strength training.
Stages 1-2: Band Inversion → Inversion-Emphasis Heel Raise
Stages 1-2: Band Inversion → Inversion-Emphasis Heel Raise
Stage 1 builds the seated sense of activating the tibialis posterior correctly, and Stage 2 carries that same force into a weight-bearing position. Skip straight to the standing exercise and it's easy to develop a habit of substituting knee or hip movement for the actual muscle, so it's worth spending the first 1-2 weeks giving the seated Stage 1 its full due.
Stage 1: Resisted Band Inversion
What you need One medium-resistance elastic band, and a doorknob or heavy table leg to anchor it to.
Starting position Sit on the floor or a mat with your legs extended. Loop one end of the band around the inside of your forefoot, near the base of the big toe, and anchor the other end so the band pulls the foot outward. Roll a towel under the knee so it rests at a slightly bent, comfortable angle.
Movement steps ① Keeping the knee and shin still, slowly pull the foot inward using only the ankle. ② Move against the band's resistance over 2-3 seconds until the foot points toward the body's midline. ③ Pause briefly, then resist the band's pull and return slowly to the start over 3-4 seconds. ④ Repeat the same sequence on the other foot.
Breathing timing Exhale as you pull the foot inward, and inhale slowly through the nose as you resist back to the start. Holding your breath during the effort just stiffens the muscles around the ankle.
Sets, reps, frequency 15 reps per side, 3 sets, 4-5 times a week. Taking the return phase slow while the pulling phase is relatively quick stimulates the tibialis posterior more precisely.
Common mistakes and fixes The most common error is rotating the knee inward or turning the whole leg to substitute for the muscle. Rest a hand lightly on the knee to confirm it isn't moving, and watch that the motion happens only below the ankle. Rolling the whole ankle through a big arc is another common mistake; the real range of motion here is smaller than it feels like it should be.
Stop if you notice Stop immediately if there's a sharp, stabbing pain along the tendon line just behind the inner ankle bone, or if that area visibly swells right after the exercise. Numbness or tingling radiating into the sole or toes is also a reason to stop.
Stage 2: Inversion-Emphasis Heel Raise
Level-up criterion Move to Stage 2 once you can finish Stage 1 at 15 reps, 3 sets per side, with no knee wobble and no pain.
Starting position Stand with feet hip-width apart, lightly holding a wall or the back of a chair. Before you start, gently draw the feet slightly inward so the tibialis posterior is already mildly engaged as you begin.
Movement steps ① Slowly raise both heels, guiding your weight so it lands under the big toe and second toe. ② At the top of the movement, hold for about 1 second while gently pressing the heels a little further inward. ③ Lower the heels slowly over 3 seconds back to the start. This eccentric phase, the slow lowering, is what delivers the strongest stimulus to the tibialis posterior.
Breathing timing Exhale as you raise the heels, and inhale through the nose while controlling the pace during the 3-second lowering.
Sets, reps, frequency 10-12 reps, 3 sets, 3-4 times a week. Once this feels manageable pain-free, doing it on one leg at a time is a good way to raise the difficulty.
Common mistakes and fixes A common error is letting the ankle roll outward while raising the heel, so the arch actually collapses further even as the heel rises. Keep a mirror nearby to check that the knee tracks over the second toe, and if it keeps rolling outward, cut the reps in half but prioritize getting the direction right. Another common issue is a shallow movement where only the toes push and the heel barely lifts; it's better to reduce the range slightly than to skip a full heel lift.
Stop if you notice Stop immediately if raising the heel triggers a sharp pain or a popping sensation just behind the inner ankle bone, and monitor it through the next day. Swelling or warmth in that area after exercising is also a reason to stop.
Stage 3: Foot-to-Foot Resistance, No Equipment, Straight to the Tibialis Posterior
Stage 3: Foot-to-Foot Resistance, No Equipment, Straight to the Tibialis Posterior
You can load the tibialis posterior substantially without a band or weight at all. The method is a seated isometric drill where you press the inner arches of both feet against each other. Unlike a band, which pulls only one foot at a time, this exercise requires both feet to push toward each other simultaneously, which lets you create a phase of near-maximal effort in both tibialis posterior muscles at once, and it has the practical advantage of being doable anywhere, an office chair or a business trip, without carrying any equipment.
Stage 3: Seated Foot-to-Foot Resisted Inversion
Level-up criterion Move to Stage 3 once you can finish Stage 2's inversion-emphasis heel raise at 10-12 reps, 3 sets, with no outward ankle roll and no pain.
Starting position Sit in a chair, or on the floor with legs extended and knees slightly bent. Keep both heels on the floor and bring the inner arches of both feet together so they touch. A slight V-shape at the toes is fine.
Movement steps ① Press both feet inward toward each other at the same time. Nothing actually moves; it's an isometric contraction where each foot resists the other. ② Hold this for 5-8 seconds. ③ Release, rest for 2-3 seconds, and repeat. ④ If one side feels noticeably weaker, you can isolate it by keeping the stronger foot fixed like a wall and having only the weaker foot press against it.
Breathing timing Don't hold your breath during the 5-8 second hold; exhale in short breaths to maintain the effort. Holding your breath during an isometric contraction can spike blood pressure sharply, which matters especially if you have hypertension, so keep breathing throughout.
Sets, reps, frequency 8-10 reps of a 5-8 second hold, 3 sets, 5 times a week. This recovers faster than the band exercise, so most people tolerate it daily, but if you wake up still feeling it the next morning, drop to every other day.
Common mistakes and fixes The most common mistake is generating the force by squeezing the knees inward rather than through the ankle. Keep a small cushion or a fist-width gap between the knees, and check with a hand on the shin that the force is coming only from the ankle and inner foot. Some people also try to curl the toes to generate force; relax the toes instead and focus the sensation on pressing through the inner arch itself, which targets the intended muscle more precisely.
Stop if you notice Stop immediately if pressing brings on a sharp, stinging pain along the tendon line just behind the inner ankle bone, or numbness and burning shooting into the sole. Inner knee pain that shows up every time you apply the pressing force is also a sign to reassess your setup.
The 6-Week Program: Weekly Targets and Level-Up Criteria
The 6-Week Program: Weekly Targets and Level-Up Criteria
Rather than starting all three exercises at once, building them up in the order below is easier on the tendon and less likely to cause pain. If you haven't met a given week's level-up criterion, don't move on, repeat that week instead.
| Week | Primary Exercise | Target Sets/Reps | Level-Up Criterion |
|---|---|---|---|
| Weeks 1-2 | Stage 1, resisted band inversion | 15 reps per side, 3 sets, 4-5x/week | Complete 15 reps, 3 sets in a row, no knee wobble, no pain |
| Weeks 3-4 | Stage 2, inversion-emphasis heel raise (keep Stage 1 as warm-up) | 10-12 reps, 3 sets, 3-4x/week | Ankle doesn't roll outward and heel fully lifts |
| Weeks 5-6 | Stage 3, foot-to-foot resistance (full routine complete) | 8-10 reps of 5-8 sec hold, 3 sets, 5x/week | No major left-right strength gap, sets completed pain-free |
If you're still on Stage 2 after 6 weeks, that isn't failure. Posterior tibial tendon dysfunction recovers at very different rates depending on severity, body weight, footwear, and how many hours a day you spend on your feet, and a flatfoot that's been left alone for years since adulthood can easily take 8-10 weeks or more. What matters more than hitting a deadline is meeting each stage's level-up criterion pain-free before moving on, in order.
All three exercises are easier to stick with when attached to something you already do, rather than carved out as separate time. Stage 1 fits well sitting on the floor while watching TV in the evening, Stage 2 while holding the sink brushing your teeth, and Stage 3 during a phone call at your desk.
It also helps to jot down your progress in a notebook or a phone app. A line or two noting the date, sets completed, and, if there was pain, which exercise and roughly how bad it felt lets you look back after two weeks and check a level-up criterion that otherwise feels fuzzy against actual numbers. Logging the left-right strength gap when you move into Stage 3 in particular makes it easier to fine-tune the program, for instance by adding an extra set for the weaker side only.
When to Skip This, and Red Flags to Stop
When to Skip This, and Red Flags to Stop
This program is built for flexible flatfoot caused by a gradually weakening tibialis posterior, in other words the early to mid stages. If the arch has already stiffened into a fixed position, or the foot has visibly deformed outward, exercise alone won't resolve it, so see an orthopedic specialist first if any of the following applies.
- The foot is already visibly rotated outward while standing and shows no flexibility, staying rigid
- The area behind the inner ankle bone has recently swollen sharply or feels hot, and walking itself is difficult, an acute state
- You've been diagnosed with a tibialis posterior tendon tear or partial tear, or had recent ankle or tendon surgery
- An inflammatory joint condition like rheumatoid arthritis is acutely flaring at the ankle
- Diabetic peripheral neuropathy has significantly reduced sensation in the foot, making it hard to feel pain signals properly
- Pain behind the inner ankle bone is severe even at rest, or bad enough at night to disrupt sleep
Even if none of these apply to you, stop immediately if any of the following show up during the exercises: sharp, stabbing pain along the tendon line just behind the inner ankle bone; visible swelling or warmth in that area right after exercising; or new numbness or burning radiating into the sole or toes. If the signal keeps recurring even after a few days off, or if the arch looks in the mirror like it's dropped noticeably more than it used to, it's safer to get the tendon evaluated by a clinician than to keep pushing through on your own judgment.
Footwear is worth checking alongside the exercises. A shoe with a sole so soft it twists easily by hand, or a slipper-style shoe with a low heel counter that lets the heel wobble side to side, forces the tibialis posterior to compensate all day long. Switching to shoes with a firmer heel counter and a comfortable toe box, on its own, has noticeably sped up how quickly some people feel the exercises working.
Near-infrared LED is not a medical device that replaces this resistance program or directly treats tendon damage; it should be understood as a wellness tool that supports recovery before and after exercise. Don't shine it directly into the eyes, and consult your physician before use if you're taking a photosensitizing medication. As a rule, don't apply it directly over open wounds or areas with reduced sensation. For a narrow area like the inner ankle, many people use it 5-30cm from the target area, 10-15 minutes per session, 3-5 times a week, though the appropriate duration can vary by skin condition and individual differences.
