This article provides general information and is not a substitute for professional medical advice. See a podiatrist or sports medicine doctor for diagnosis and a treatment plan specific to your condition.
Quick Answer
Hammer toes in runners and cyclists are primarily caused by narrow toe boxes forcing toes into sustained flexed positions, combined with a muscle imbalance where the long extrinsic flexor tendons overpower the small intrinsic foot muscles. For cyclists, incorrect cleat position is an additional major driver. Caught early while the joint is still flexible, hammer toes can be reversed with footwear changes, toe exercises, and orthotics. Once rigid, surgery is the only correction. Seek a podiatrist before that threshold.What Is a Hammer Toe? (And How It Differs from Claw Toe and Mallet Toe)
The three terms — hammer toe, claw toe, and mallet toe — describe deformities of the lesser toes (toes 2–5) that are related but affect different joints. Understanding which one you have matters for treatment.
A hammer toe is characterised by flexion (downward bending) at the proximal interphalangeal joint — the middle joint of the toe. The metatarsophalangeal joint (where the toe meets the foot) is typically extended or neutral. The result is a toe with a characteristic raised knuckle that presses against the upper of the shoe.
A claw toe involves flexion at both the proximal and distal interphalangeal joints, with the toe curled more aggressively downward throughout its length. Claw toes typically affect all four lesser toes together rather than just the second toe, and are more strongly associated with intrinsic muscle weakness and tight calf muscles.
A mallet toe affects only the distal interphalangeal joint — the joint closest to the toenail — causing the tip of the toe to point downward. It’s less common than the other two and presents with tip-of-toe pain rather than dorsal (top-of-toe) pain.
In practice, the terms hammer toe and claw toe are often used interchangeably — even by clinicians — and the management principles are largely the same. The second toe is most commonly affected in isolation, while claw toe patterns typically involve all four lesser toes. For the purposes of this article, “hammer toe” refers to the broader category of lesser toe flexion deformities most commonly seen in runners and cyclists.
The Underlying Cause: Muscle Imbalance
All hammer toe deformities, regardless of trigger, arise from the same fundamental mechanism: an imbalance between the intrinsic muscles of the foot (the small muscles that originate and insert entirely within the foot, responsible for straightening and stabilising the toes) and the extrinsic flexor tendons (the longer tendons that originate in the calf and lower leg and pull the toes downward).
When intrinsic foot muscles are strong, they hold the toes flat against the ground and prevent the toe joints from flexing under load. When they weaken — through disuse, muscle fatigue, prolonged compression, or neurological factors — the long flexor tendons become relatively dominant. They pull the toe into a bent position with every step and pedal stroke. Over time, if the toe is held in that flexed position for long enough by a tight shoe, the muscle and tendon shortening becomes permanent. The joint capsule contracts, the collateral ligaments stiffen, and what started as a flexible, correctable deformity becomes a fixed, rigid one.
This progression — from flexible to semi-rigid to rigid — is the defining feature of hammer toe pathology. It is gradual, often painless in the early stages, and almost always preventable if caught before the transition to rigidity.
How Running Causes Hammer Toes
Running creates several distinct hammer toe risk factors that don’t apply to normal walking.
Foot Swelling
Feet swell during running — consistently, in almost every runner, from increased blood flow, heat, and impact-related fluid redistribution. The average foot can increase by half a shoe size or more over the course of a long run. A running shoe fitted correctly at the start becomes progressively tighter as the run continues, compressing the toes forward into the toe box. For runners who already have a second toe longer than the big toe (a common anatomical variant), this means the second toe is being bent against the front of the shoe for potentially hours at a time — the exact sustained flexion pressure that drives hammer toe formation. Our guide on hot spots while running covers foot swelling and shoe fit in detail, including how to size shoes to account for this.
Fatigue-Induced Toe Gripping
When the foot’s intrinsic muscles fatigue late in a long run, many runners unconsciously claw their toes against the insole for additional stability and propulsion — a compensatory mechanism that loads the flexor tendons with every step. Research shows this effect is more pronounced on downhill gradients, where the foot slides forward and the toes brace against the shoe front. This is why runners who train extensively on hilly terrain, or who do significant downhill racing, have a higher incidence of toe deformities and metatarsal injuries. Our guide on running surfaces covers how surface type affects lower limb loading patterns.
Narrow or Tapered Toe Boxes
Many performance running shoes — and virtually all traditional dress shoes — are designed with cosmetically tapered toe boxes that compress the toes laterally. This not only forces the toes together but causes the second and third toes to buckle upward as they have nowhere else to go. The shoes that are most likely to accelerate hammer toe progression are those that narrow significantly in the last third of the shoe length, regardless of the stated width. The test: remove the insole from your shoe and stand on it. If your toes overhang the sides or the front, the shoe is too narrow for you.
Wrong Shoe Length
Running shoes should provide approximately half a thumb’s width (about 10–12mm) between the longest toe and the end of the shoe. Most runners undersize their running shoes relative to their training shoes, partly because snugness feels more supportive. In practice, shoes that are even marginally short force the toes into continuous low-grade flexion against the front, compounding the foot-swelling problem. Always size running shoes at the end of the day and after a run when feet are at their largest. See our guide on running shoes for metatarsal pain for shoe selection criteria that also reduce hammer toe risk.
How Cycling Causes Hammer Toes
Cycling creates a distinct set of hammer toe risk factors that are different in important ways from running. The primary difference is that cycling involves sustained, repetitive loading of the forefoot in a fixed position — unlike running where the foot lifts off and the toes briefly decompress.
Narrow Cycling Shoe Design
Cycling shoes are designed around aerodynamics, stiffness, and power transfer — not foot anatomy. Most performance cycling shoes have narrow, low-volume toe boxes that suit a minority of foot types very well and compress the majority. In a 4-hour ride with a cadence of 90 rpm, that’s 21,600 pedal strokes — 21,600 opportunities for the toe box to reinforce a flexed toe position. Even shoes that feel comfortable for a 30-minute spin can become painfully tight on a long ride as feet swell. The solution is to size cycling shoes generously (many cyclists benefit from going half a size up from their normal street shoe size) and to explicitly prioritise toe box width when selecting shoes rather than defaulting to aesthetics or brand loyalty.
Cleat Position
Incorrect cleat positioning is a significant and underappreciated cause of hammer toe progression in cyclists. When cleats are positioned too far forward — ahead of the metatarsal heads — the pivot point of the pedal stroke is placed under the toes rather than under the ball of the foot. This forces the toes to bear substantially more load per pedal stroke than they’re designed for, and the constant downward pressure on the toes during the power phase progressively stresses the flexor tendons. The correct position for most riders is with the centre of the cleat directly beneath the first metatarsal head (the bony prominence behind the big toe). Our guide on the KOPS method for cleat and saddle position explains the correct pedalling axis setup in detail. If you’ve been riding with cleats positioned incorrectly for a long time, having a professional bike fit performed is one of the highest-value interventions for foot health as well as power efficiency.
High Cleat Tension and Pedal Type
High-tension clipless pedals require significant heel-down force to unclip, which means many cyclists unconsciously curl their toes during efforts to prevent accidental unclipping. This habitual toe-gripping under load is identical in mechanism to the fatigue-induced gripping in runners — the flexor tendons repeatedly overpower the intrinsic foot muscles. Reducing cleat tension and practising smooth, deliberate unclipping technique reduces this compensation. Our guide on cycling with metatarsal injuries covers forefoot anatomy and loading in detail.
Flexible vs. Rigid Hammer Toes: The Critical Distinction
The most important clinical decision in hammer toe management is whether the deformity is flexible or rigid. This determines what’s possible without surgery.
| Stage | What it means | Can you straighten it? | What works |
|---|---|---|---|
| Flexible | Muscles and tendons still pliable; joint moves normally | Yes — manually or when bearing weight | Footwear changes, exercises, orthotics, taping. Full reversal is possible. |
| Semi-rigid | Tendons beginning to contract; joint stiff but not fixed | Partially — with effort or passive stretching | Same conservative measures slow progression but reversal is partial. Earlier intervention is better. |
| Rigid | Tendons fully contracted; joint cannot be moved | No — not by any conservative means | Conservative measures manage symptoms (pain, corns, footwear fit) but cannot correct the deformity. Surgery is the only correction. |
The flexible stage is the only window where the hammer toe can be fully corrected without surgery. Many athletes remain in the flexible stage for years, particularly if their shoes are reasonably well-fitted most of the time and the deformity only appears under training load. The transition to rigidity accelerates when training volume is high, shoes are consistently narrow, and no corrective measures are taken.
Self-test: With your foot off the ground, can you manually press the affected toe flat with your finger? If yes, the deformity is still flexible. Does it spring back to the bent position when you release it but remain passively straightenable? That’s semi-rigid. If the toe cannot be straightened at all with gentle manual pressure, it is rigid. When in doubt, see a podiatrist for formal assessment.
Symptoms: What Hammer Toes Feel Like in Runners and Cyclists
The symptom pattern differs somewhat between runners and cyclists, reflecting the different loading mechanisms.
In runners, the most common presentation is pain or pressure on the dorsal surface (top) of the affected toe — where the raised PIP joint rubs against the upper of the shoe. Callus formation at this point is often the first visible sign. Pain may also occur at the tip of the toe if the toe is being pushed hard into the front of the shoe on downhills. Many runners also notice that certain shoes that used to fit have become unwearable, or that they’re getting blisters in new places.
In cyclists, the symptom pattern often includes numbness or tingling in the toes during long rides (from sustained compression of the digital nerves), generalised forefoot aching post-ride, and a sense of the toes feeling cramped and rigid after removing cycling shoes. Corns on the dorsal surface of the toe and calluses under the metatarsal heads are also common.
Both groups may experience secondary gait compensations as the condition progresses — limping, altered foot strike patterns, or distributing load away from the affected toe. These compensations create upstream injury risk at the ankle, knee, and hip. Our guide on hip pain after running covers how foot mechanics cascade up the kinetic chain, and our piece on feet slapping the ground when running addresses gait compensation patterns.
Exercises for Hammer Toes
These exercises target the intrinsic foot muscles that have been weakened relative to the long extrinsic flexors — the root cause of the muscle imbalance. They are most effective in the flexible stage and should be performed daily, not just before training.
1. Toe Curls (Towel Pickup)
Place a small towel or a marble on the floor. Using only your toes, scrunch the towel toward you or pick up the marble and release it. This directly activates the intrinsic flexors in a controlled way that strengthens the correct muscles without reinforcing the deforming pattern. Aim for 3 sets of 10–15 repetitions per foot, twice daily.
2. Manual Toe Stretches
Sit with the foot resting on the opposite knee. Grasp the affected toe and gently pull it into extension (straightening the PIP joint), holding for 10–15 seconds. Then move the toe through its full range of motion — flexion and extension — to mobilise the joint capsule and prevent further stiffening. Perform 10 repetitions per toe, twice daily. This is the most direct intervention for maintaining joint flexibility in the semi-rigid stage.
3. Toe Splay and Spread
Sit or stand with the foot flat. Spread all five toes as wide apart as possible, hold for 5 seconds, then relax. This activates the interosseous muscles — the deep intrinsic muscles that both spread the toes and resist the flexion pull of the long tendons. Initially many people find this almost impossible on the affected foot because the intrinsic muscles have become dormant. Persistence over 4–6 weeks typically produces significant improvement. 3 sets of 10 repetitions per session.
4. Short Foot Exercise (Foot Doming)
Sit with the foot flat on the floor. Without curling the toes, attempt to shorten the foot — pulling the ball of the foot toward the heel by arching through the midfoot. This activates the intrinsic muscles of the entire foot, including those that hold the toes straight. It’s more challenging than it sounds and is one of the most researched exercises for improving intrinsic foot muscle strength. Our guide on eccentric heel drops for runners covers adjacent exercises for foot and lower leg structural health.
5. Towel Scrunches
Place a small towel flat on the floor. Using the toes, scrunch the entire towel under the foot, then smooth it back out. This exercises both the flexors and extensors of the toes through a controlled range of motion. Less specific than the marble pickup but easier to perform and good for general intrinsic muscle conditioning.
Conservative Treatment Options
| Treatment | What it does | Stage applicable | Notes |
|---|---|---|---|
| Wide toe box shoes | Removes compression forcing the flexed position; allows toe to rest straight | Flexible and semi-rigid | Both width and depth matter. The toe needs room up as well as sideways. |
| Toe exercises | Strengthens intrinsic muscles; rebalances muscle forces on the joint | Flexible and semi-rigid | Must be performed consistently over 6–12 weeks for meaningful effect. |
| Toe straightener/splint | Holds the toe in neutral position during rest or light activity | Flexible and semi-rigid | Effective for maintaining position; does not permanently correct once removed. |
| Buddy taping | Stabilises the affected toe against an adjacent one; reduces rubbing and dorsal pressure | All stages | Practical during training. Use non-adhesive foam padding between toes to prevent blisters. |
| Toe pads / silicone caps | Cushions the dorsal joint against shoe pressure | All stages | Symptom management only; doesn't address the deformity itself. |
| Orthotics / metatarsal pads | Redistributes forefoot pressure away from the metatarsal heads; reduces clawing stimulus | Flexible and semi-rigid | Custom orthotics most effective; OTC metatarsal pads a useful starting point. |
| Cleat repositioning (cyclists) | Moves pedalling axis to correct position, reducing load on flexor tendons | All stages | High-value intervention. Consider professional bike fit. |
| Corticosteroid injection | Reduces inflammation and pain at the PIP joint | Semi-rigid and rigid for symptom management | Temporary relief only; does not address deformity. |
Shoe Selection: What to Look For
The single most impactful change for most runners and cyclists developing hammer toes is footwear. The criteria that matter most:
For running shoes: prioritise a wide, deep toe box over all other features. The toe box should allow all five toes to rest flat without any lateral compression, and there should be at least one thumb’s width between the longest toe and the front of the shoe. Brands known for wider toe boxes include Hoka (particularly the Bondi and Clifton), New Balance (their 4E wide options), Altra (anatomically shaped wide toe box across almost all models), and Brooks (Glycerin and Ghost in wide widths). Try on running shoes at the end of the day, ideally after a short run, and walk and jog in them before buying. Our guide on running shoes for flat feet covers shoe selection criteria in detail, including toe box considerations.
For cycling shoes: Look for high-volume, wide toe box options. Lake Cycling (who produce a specific wide-fit range), Shimano (who offer wide sizing across several models), and Bont (with heat-mouldable options) are the brands most consistently cited by cyclists with foot health issues. Avoid shoes that have any perceptible pressure on the toes when you pedal. If your current shoes cause toe discomfort within the first hour of a ride, they are already compressing your forefoot inappropriately — that compression is accumulating damage whether or not it’s painful yet. On long rides, slightly loosening the forefoot BOA closure or strap after the first hour can meaningfully reduce sustained compression as the foot swells.
For everyday footwear: The damage to hammer toe progression doesn’t only occur during training. Spending 8 hours a day in narrow dress shoes or tapered trainers negates the benefit of wide training shoes. Minimising time in any footwear that visibly compresses the toes is a meaningful part of management. Off-the-bike and off-the-run, wide-toe-box casual shoes, sandals with toe room, or barefoot time at home all help the intrinsic foot muscles maintain their natural length and function.
When to See a Podiatrist
Conservative self-management is appropriate for mild, flexible hammer toes in otherwise healthy athletes. A podiatrist should be consulted in the following circumstances:
The toe cannot be manually straightened — the deformity is rigid. Conservative measures cannot correct a rigid hammer toe, and a podiatrist can assess whether surgery is appropriate and what the realistic outcomes are.
Pain during normal walking or daily activities. When the hammer toe is impacting movement off the training surface, the condition has progressed beyond what footwear changes and exercises can manage alone.
Corns or calluses that keep returning or become inflamed. A podiatrist can debride these and assess the underlying biomechanical pressure that’s causing them.
Skin breakdown over the dorsal joint. Open wounds over bony prominences, particularly in the presence of diabetes or circulation issues, require medical attention promptly. Diabetic athletes should see a podiatrist at the first sign of any toe deformity.
Suspected plantar plate tear. A mechanism of sudden sharp pain at the base of a toe, sometimes accompanied by an audible or sensed pop during running or jumping, can indicate a plantar plate injury — a distinct but related forefoot condition that requires specific management.
Surgical Options for Rigid Hammer Toes
When conservative measures have failed or the hammer toe is rigid, surgery is the only corrective option. The most common procedures are:
Arthroplasty — removal of part of the PIP joint to allow the toe to straighten. This is the most common procedure for isolated rigid hammer toe and is typically performed as a day procedure. Recovery involves 2–6 weeks in a post-operative shoe, transitioning to a stiff athletic shoe, with full return to running typically at 3–4 months.
Arthrodesis (fusion) — permanently fusing the PIP joint in a straightened position using a pin or implant. The joint loses mobility but the toe is permanently corrected. More reliable for severe or recurrent deformities.
Flexor tendon transfer — the flexor tendon that is causing the downward pull is detached from its insertion at the tip of the toe and reattached to the dorsal (top) surface of the toe, converting a deforming force into a correcting one. Used more commonly for claw toe patterns affecting multiple toes.
Surgery carries the usual risks: infection, nerve damage, stiffness, recurrence (estimated at around 10% at long-term follow-up, more common in second-toe repairs). Most athletes can return to cycling before running due to the lower impact forces involved. Full return to competitive running is typically 3–6 months post-procedure. A podiatric surgeon or foot and ankle orthopaedic specialist should guide the decision and procedure choice based on the specific deformity, the affected joint, and the athlete’s goals.
Running or Cycling Through Foot Problems?
A coach can help you modify training load and technique while you address a foot injury — and identify whether your current gear and form are contributing to the problem.
FAQ: Hammer Toes in Runners and Cyclists
Can running cause hammer toes?
Yes. The main mechanisms are: foot swelling during long runs compressing the toes into a narrow toe box; fatigue-induced toe gripping for stability; and chronically narrow or short shoes. All three drive the flexor tendon overload that underlies hammer toe formation.
Can cycling cause hammer toes?
Yes. Narrow cycling shoe toe boxes, cleats positioned too far forward, and habitual toe-gripping under high pedalling loads all contribute. The hours of sustained forefoot compression in cycling shoes are particularly problematic for progressive tendon shortening.
What is the difference between flexible and rigid hammer toes?
A flexible hammer toe can still be manually straightened — conservative treatment can fully reverse it. A rigid hammer toe cannot be straightened by any non-surgical means. The transition from flexible to rigid can take years, but once rigid, surgery is the only correction.
What exercises help hammer toes?
Toe curls (marble or towel pickup), manual toe stretches, toe splay exercises, short foot/doming exercises, and towel scrunches all strengthen the intrinsic foot muscles that counterbalance the deforming flexor tendon pull. Daily practice over 6–12 weeks is needed for meaningful effect.
When should I see a podiatrist about hammer toes?
When the toe is rigid, when pain affects daily walking, when corns become inflamed or skin breaks down, or if you’re diabetic and notice any toe deformity. See our guides on cycling with metatarsal injuries and running shoes for forefoot pain for related conditions that often present alongside hammer toes.
What running shoes are best for hammer toes?
Wide toe box and deep toe box are the two criteria that matter most. Altra, Hoka (Bondi/Clifton), New Balance in wide/extra-wide fittings, and Brooks Glycerin in wide sizes are commonly recommended. Fit shoes at the end of the day and ensure at least one thumb’s width between the longest toe and the shoe front.
