The posterior tibial tendon (PTT) is a deep-lying structure in the lower leg and ankle that plays a significant role in foot mechanics. Its primary job is to provide dynamic support to the medial arch of the foot, acting like a natural spring to maintain shape during movement. Issues with this tendon, often referred to as Posterior Tibial Tendon Dysfunction (PTTD), are a frequent source of pain and instability, commonly leading to adult-acquired flatfoot. Maintaining the health of this tendon through specific stretching and strengthening routines is a proactive way to preserve foot function.
The Function and Anatomy of the Posterior Tibial Tendon
The posterior tibial muscle originates from the back surfaces of the tibia and fibula bones in the calf. The tendon extends down the leg, curves behind the bony prominence on the inside of the ankle (medial malleolus), and attaches to multiple bones on the underside of the foot, particularly the navicular bone. This anatomical pathway allows the tendon to perform two major actions: plantarflexion (pointing the foot down) and inversion (turning the sole of the foot inward).
The tendon’s broad insertion points support the foot’s medial longitudinal arch. By contracting, the PTT lifts and stabilizes the arch, preventing collapse during weight-bearing activities like walking or running. When the tendon becomes overused, inflamed, or degenerated, it loses this ability, resulting in pain along the inside of the ankle and progressive foot flattening.
Specific Stretches to Improve Flexibility
Flexibility in the calf muscles is needed because tightness in the gastrocnemius and soleus can increase strain on the PTT. The standing calf stretch targets the gastrocnemius muscle. To perform this, stand facing a wall, place the affected leg back with the knee straight and heel on the floor, and lean forward until a stretch is felt in the calf. Hold this position for 30 seconds and repeat three times.
To target the deeper soleus muscle, repeat the standing stretch but with the knee of the back leg slightly bent while keeping the heel on the ground. Bending the knee isolates the soleus, which helps relieve tension that can indirectly overload the PTT. It is also beneficial to perform a hamstring stretch, as tightness here can alter gait and increase foot stress. A simple towel stretch involves sitting with the leg straight, looping a towel around the ball of the foot, and gently pulling back while maintaining a straight knee. Hold each stretch for at least 30 seconds without bouncing.
Strengthening Exercises for Stability
Strengthening the PTT is necessary for long-term stability and preventing dysfunction recurrence. A foundational exercise is seated ankle inversion with a resistance band, which directly works the posterior tibial muscle. Sit with the leg slightly bent, loop a resistance band around the foot, anchor the other end, and slowly turn the foot inward against the band’s tension. Perform two sets of 10 to 15 slow, controlled repetitions, focusing on the inward pull of the foot.
Heel raises are important for building dynamic arch support, especially the eccentric (lowering) phase. Begin by rising onto the balls of both feet, then lift the unaffected leg and lower down very slowly only on the affected foot. This emphasizes the PTT’s role in controlling arch collapse; the lowering phase should take about five seconds. Exercises that strengthen the intrinsic foot muscles, such as towel curls or marble pick-ups, also help improve local arch control. For towel curls, sit and use the toes to crumple a small towel toward the heel, repeating for two to three sets of 10 to 15 repetitions.
When to Seek Professional Guidance
While self-care through stretching and strengthening is beneficial, it is not always sufficient, especially if symptoms are severe or persistent. Consult a medical professional, such as a physical therapist or podiatrist, if pain is sharp, worsens significantly with activity, or prevents weight-bearing.
Visible changes in foot structure, like progressive arch flattening or the inability to stand on tiptoes on the affected foot, indicate that professional treatment is needed. These exercises are typically part of a conservative treatment plan and should be performed four to seven times per week. If no improvement is seen after one to two months, or if the condition progresses, a specialist can offer a more advanced diagnosis and treatment, which may include custom orthotics or bracing.