The single most important clinical test for flat feet is the Jack's Toe Extension Test (also called the hallux dorsiflexion test). When the big toe is passively extended, the plantar fascia tightens via the windlass mechanism, and a true flexible flat foot will immediately demonstrate a restoration of the medial arch — even in a person whose arch is completely flat on standing. This confirms the arch structures are intact and the foot is mechanically capable of forming an arch. The treatment goal in flexible flat feet is to retrain the neuromuscular system to actively maintain this arch during weight-bearing.

Rigid flat feet — where no arch appears even with the Jack's test — indicate structural deformity (tarsal coalition, arthritic subtalar joint, severe PTTD with spring ligament rupture). Rigid flat feet require orthopaedic surgical evaluation alongside physiotherapy. At Curis 360 Banashankari and Jayanagar clinics, our physiotherapists perform a comprehensive foot assessment including the Jack's test, navicular drop measurement, and subtalar range of motion to determine the appropriate management pathway.

The posterior tibial muscle and the intrinsic foot muscles (primarily flexor digitorum brevis and abductor hallucis) are the 'active subsystem' of the arch — they provide dynamic arch support during walking and running. In symptomatic flat feet, these muscles are typically inhibited and poorly activated. The primary activation exercise prescribed at our Vasanthapura and Banashankari clinics is the Short Foot Exercise (SFE), developed by Janda.

The SFE involves shortening the foot by actively drawing the ball of the foot toward the heel — without curling the toes — creating a contraction of the arch-lifting intrinsic muscles. It is performed in sitting first (3 sets of 10, 5-second holds), then standing (more difficult due to load), and finally single-leg standing. The SFE is combined with toe spread (active toe abduction) and towel scrunching to comprehensively activate the intrinsic foot musculature. Patients accessing our home physiotherapy service in Bengaluru or our online physiotherapy service across India receive video demonstrations of these exercises with verbal cues to ensure correct technique.

The posterior tibial muscle is the most powerful arch-lifting muscle in the leg. Its tendon runs behind the medial malleolus and inserts into the navicular bone at the apex of the medial arch. Strengthening this muscle — through tibial inversion exercises with resistance bands and single-leg heel raises with an arch lift — is the cornerstone of long-term flat foot management. At our Jayanagar and Vasanthapura clinics, we use resistance band tibial inversion in progressive positions: seated to standing to single-leg standing.

Calf strengthening (gastrocnemius and soleus) is equally important because calf weakness forces excessive subtalar pronation during push-off. Our programme includes single-leg heel raises with the knee straight (gastrocnemius) and with the knee bent (soleus), performed both on a flat surface and on the edge of a step. We combine this with hip abductor and external rotator strengthening — side-lying clamshells, lateral band walks, and single-leg squat control — to control the proximal drivers of valgus knee collapse and tibial internal rotation that accompany flat feet.

Custom-made semi-rigid foot orthotics are the most effective immediate intervention for symptomatic flat feet. They work by supporting the medial longitudinal arch in an anatomically correct position, reducing navicular drop, and diminishing the excessive tibial internal rotation that causes knee and back pain. At Curis 360 Banashankari and Vasanthapura clinics, orthotic prescription follows a video gait analysis — we record your walking and running barefoot and in shoes at slow motion, then prescribe orthotics corrected to the precise degree of arch support your foot mechanics require.

Footwear is equally important. We prescribe motion-control or stability running shoes (Brooks Adrenaline GTS, ASICS Kayano, New Balance 860 are commonly cited examples) that have medial post reinforcement to limit excessive pronation. We strongly advise against minimalist or zero-drop shoes for patients with symptomatic pes planus, as these remove all mechanical arch support. For daily use, sandals with arch support (Teva, Birkenstock with arch support models) are recommended over flat chappals, which provide zero arch scaffolding.

PTTD is a progressive condition in which the posterior tibial tendon degenerates and eventually ruptures, causing the medial arch to collapse progressively in adulthood. It is graded Stage I–IV: Stage I involves tendon inflammation with intact arch; Stage II involves flexible flat foot with tendon incompetence; Stage III involves rigid flat foot; Stage IV involves ankle joint involvement. Physiotherapy is highly effective for Stages I and II.

The classic clinical sign of PTTD is the 'too many toes' sign — viewed from behind, more toes are visible on the lateral side of the affected foot compared to the other side, due to forefoot abduction. The single-leg heel raise test confirms tendon competence: a patient with intact posterior tibial tendon can perform a single-leg heel raise, inverting the heel as they rise; a patient with PTTD cannot invert the heel and may be unable to complete the movement. Our physiotherapists at Curis 360 Banashankari and Jayanagar diagnose and stage PTTD clinically, refer for MRI confirmation if Stage II-III is suspected, and design a tendon-specific rehabilitation programme accordingly.