Achilles Tendon Pain in Runners: A Complete Care Guide

Why the Achilles Tendon Trips Up So Many Runners

The Achilles tendon is the thickest, strongest tendon in the body, connecting the calf muscles (gastrocnemius and soleus) to the heel bone (calcaneus). Every walking step, run, and jump sends it tensile loads of roughly 6 to 8 times body weight. That strength comes with a tradeoff: the tendon is also one of the more overuse-prone structures in the lower leg.

Achilles tendinopathy shows up disproportionately in runners, marathoners, soccer players, and badminton players — anyone doing repetitive push-off and jumping movements at the ankle. Data cited by Korean orthopedic societies puts the figure at roughly 9 to 11 percent of runners experiencing Achilles-related pain at least once during training. Part of what makes this injury stubborn is anatomy: the region 2 to 6 centimeters above the heel insertion gets comparatively poor blood supply, so healing after microdamage is slow. Left unmanaged, that can progress to chronic tendinopathy or, rarely, a partial or complete rupture.

Why Location Matters

Treatment for Achilles tendinopathy depends heavily on exactly where the pain sits. Pain in the mid-portion of the tendon and pain at the insertion point on the heel bone can call for opposite strategies — different causes, different stretching directions, even different shoe choices. Applying the same generic stretching routine to both can make things worse. Getting the location right is the actual starting point for recovery, not an afterthought. Related reading: Plantar Fasciitis Guide

Causes of Achilles Tendinopathy by Location

Achilles tendinopathy is rarely caused by one single thing — it usually builds up from several overlapping risk factors, and the mechanics differ depending on where the pain lands. Related: Achilles Tendon Pain: Causes and Care

Mid-portion tendinopathy (roughly 55 to 65 percent of cases)

• The watershed zone: the segment 2 to 6cm above the insertion has the sparsest blood vessel network in the tendon, so microdamage there heals slowly on its own.
• Sudden jumps in training volume: increasing weekly mileage by more than 10 percent, or abruptly adding hill work or interval sessions, is strongly associated with new cases.
• Weak or inflexible calves: when the gastrocnemius and soleus lack sufficient eccentric strength, the landing load that the muscle should absorb gets passed straight into the tendon tissue instead.

Insertional tendinopathy (roughly 20 to 25 percent of cases)

• Haglund deformity: a bony prominence at the back of the heel bone rubs against the shoe's heel counter, creating chronic irritation.
• Heel bone spurs: repeated traction forces at the insertion frequently lead to calcification or bone spur formation.
• Overly aggressive dorsiflexion stretching: for the insertional type specifically, forcing the ankle into deep dorsiflexion increases compressive irritation at the attachment and can make symptoms worse rather than better.

Shared risk factors

• Flat feet and overpronation: when the foot rolls inward excessively, the tendon absorbs a repeated twisting, whip-like load.
• Worn-out running shoes: shoes pushed past 500 to 800km lose cushioning and shock absorption.
• Fluoroquinolone antibiotics: drugs such as ciprofloxacin have been linked, in rare cases, to a higher risk of tendon damage or rupture. New tendon pain while on one of these warrants a conversation with your prescriber.
• Age and metabolic factors: collagen regeneration in tendons slows noticeably past the late thirties, and conditions like diabetes and dyslipidemia raise risk further.

Symptom Stages and a Self-Check

Achilles tendinopathy tends to creep in gradually rather than announce itself. Knowing which stage you're in is genuinely useful for deciding how much to pull back on training.

Stage 1: Reactive tendinopathy

• Fine at the start of a run, then an ache builds in the middle or later portion of the session
• Pain and stiffness on the first steps the morning after training, usually easing within 5 to 10 minutes
• Localized tenderness when you press directly on the tendon

Stage 2: Dysrepair

• The tendon feels thickened or spindle-shaped when you run a finger along it
• Pain is present from the first minutes of exercise but eases somewhat after warming up
• Pain reproduces on stairs and on single-leg tiptoe raises

Stage 3: Degenerative tendinopathy

• Pain persists even during ordinary walking
• A discrete nodule is palpable within the tendon
• Climbing stairs, or even starting to run at all, becomes genuinely difficult

Self-check: telling the two locations apart

Related: Daily Knee Care Routine

If two or more of the following apply, it is worth booking a professional evaluation:

1. Post-exercise pain has lasted more than two weeks
2. A single-leg heel raise on the affected side is noticeably weaker or more painful than the other
3. You felt a sudden sensation of being struck in the heel while walking — a possible rupture sign
4. The tendon looks visibly thicker or a nodule is palpable
5. Morning stiffness lasts more than 10 minutes

When to See a Doctor and How to Spot a Rupture

Most Achilles tendinopathy responds to conservative management, but a tendon rupture is a different problem entirely and needs urgent care. It's worth being able to tell the two apart.

Go to the emergency room right away (suspected rupture)

• A sudden feeling of being kicked in the heel, or an audible pop: classically happens during a sudden jump or change of direction and is a textbook rupture sign
• Complete inability to do a single-leg heel raise: regardless of how much it hurts, total inability to rise onto the toes of one foot should raise suspicion for a partial or full tear
• A positive Thompson test: lying face down, squeezing the calf normally makes the foot flex — if nothing happens, that's concerning
• A palpable gap or defect along the course of the tendon

See a doctor within two weeks if

• Pain hasn't improved after four weeks of reduced training and self-care
• The tendon keeps getting thicker, or a nodule keeps growing
• Night pain keeps returning despite NSAIDs
• New pain shows up alongside an existing condition like diabetes or a rheumatic disease

How it gets diagnosed

See also: Daily Shoulder Care Routine

• Physical exam: the Thompson test, palpation to locate tenderness precisely, and the single-leg heel raise test
• Ultrasound: widely used and accessible for checking tendon thickness, partial tears, and neovascularization
• MRI: reserved for a more precise look at internal degeneration and the extent of a tear

Phased Management: Acute to Chronic

How you manage Achilles tendinopathy should shift depending on how acute the pain is and which stage of tendon pathology you're dealing with.

Acute phase (0 to 2 weeks)

Also useful: Plantar Fasciitis Guide

• Relative rest, not total rest: keep walking, but cut out the jumping and sprinting movements that provoke pain
• Ice: 15 to 20 minutes when pain is sharp right after activity, two to three times a day
• Cut training volume by 30 to 50 percent immediately: a study by Silbernagel and colleagues (2007) in the Journal of Orthopaedic & Sports Physical Therapy found that patients who kept training while managing pain at or below a 5 out of 10 had better long-term outcomes than those who tried to eliminate pain entirely by stopping
• A temporary heel lift: a 1 to 1.5cm heel pad in the shoe reduces the peak load the tendon takes on with each step

Subacute phase (2 to 6 weeks)

• Isometric holds: when pain is still high, start with a static tiptoe hold of 30 to 45 seconds and build load from there
• Introduce eccentric work: once pain sits at a tolerable 3 to 4 out of 10, begin the Alfredson protocol (details in the next section)
• Heat before exercise: 15 to 20 minutes of warm compress to improve blood flow and loosen tissue

Chronic phase (past 6 weeks)

• Progressive loading: move from pure eccentric work to combined concentric-eccentric loading, and eventually plyometric jump training
• Correct foot alignment: arch support or custom orthotics for overpronation reduce the twisting load on the tendon
• Extracorporeal shockwave therapy (ESWT): an option some physicians consider for chronic cases that haven't responded to conservative care
• Return-to-run benchmark: once single-leg heel raise reps on the affected side reach 90 percent or more of the unaffected side, a gradual return to running can be considered

The Eccentric Loading Protocol

The single best-supported exercise for Achilles rehab is the eccentric calf raise. Eccentric contraction means the muscle produces force while it's lengthening — and this specific loading pattern is believed to drive collagen realignment and rebuild tendon strength in a way concentric work doesn't.

The Alfredson protocol

Swedish orthopedic surgeon Hakan Alfredson published this approach in the American Journal of Sports Medicine in 1998, and it has since become the standard for Achilles rehab. In the original study, most of the 15 patients with chronic mid-portion Achilles tendinopathy returned to sport pain-free after 12 weeks of eccentric exercise alone — no other treatment.

1. Starting position: stand on a step or curb with only the front of your foot on the edge
2. The movement: rise onto your toes with both feet, then shift all your weight onto the painful leg and lower the heel down slowly over 3 to 4 seconds
3. Split by knee position: perform one set with the knee straight (targets the gastrocnemius) and another with the knee slightly bent (targets the soleus)
4. Volume: 15 reps x 3 sets for each knee position, twice a day (morning and evening), 7 days a week, for a full 12 weeks
5. Progressing the load: once you can do it pain-free, add weight with a loaded backpack to keep progressing

A modified version for insertional cases

For insertional Achilles tendinopathy, letting the heel drop below the edge of a step drives dorsiflexion that compresses the tendon against bone and can flare symptoms. The recommended fix is to do the exercise on flat ground instead of a step, lowering the heel only to floor level rather than below it.

Isometric holds (start here if pain is severe)

• Hold a tiptoe position against a wall or step for 30 to 45 seconds, 5 repetitions
• Often gives noticeable, immediate relief from acute pain — useful right before a training session or competition

What to watch for

• Keep pain at or below 5 out of 10 during the exercise, and dial back if anything lingers into the next morning
• Pain often ticks up a bit in the first two weeks — that's usually a normal sign of the tendon adapting to load, not a red flag on its own
• If acute swelling or warmth spikes right after a session, back off intensity and check in with a professional

Using Near-Infrared Wellness Care

Eccentric exercise is the backbone of Achilles rehab, but near-infrared LED care can sit alongside it as a wellness routine that supports muscle conditioning before and after training. Near-infrared devices are not medical treatment — they're a home wellness aid people use to support calf muscle relaxation and a sense of improved local circulation.

When to use it

• Before training: apply to the calf muscles ahead of eccentric raises as part of a warmup routine
• After training: use it as a cooldown to support muscle relaxation and a sense of recovery post-session
• On rest days: keeping the habit up even on non-training days can help maintain a consistent conditioning routine

How to use it

• Keep a distance of about 5 to 10cm from the skin over the calf and around the heel
• 10 to 15 minutes per area, once or twice a day
• It's generally recommended to apply it broadly across the whole calf immediately after finishing an eccentric session
• During the first few days of acute swelling or warmth, prioritize ice, and layer in the near-infrared routine once swelling has settled

To be clear, near-infrared care is a supporting wellness routine, not a replacement for the eccentric exercise protocol or for managing your training load. If pain persists or gets worse, see a doctor first.

Running Shoes and Training Load Management

Achilles tendinopathy is shaped heavily by training habits and gear choices, so checking these everyday factors matters just as much as any specific exercise for keeping it from coming back.

Choosing and replacing running shoes

• Replacement interval: cushioning and support degrade after 500 to 800km (roughly 3 to 6 months at 30km a week), so plan to replace around then
• Heel shape: if you have insertional Achilles tendinopathy, look for shoes with a soft, low heel counter to cut down on friction
• Drop height: switching abruptly to a low heel-to-toe drop shoe increases Achilles load and needs a gradual adjustment period

Training load management: the 10 percent rule

• Increase weekly running distance by no more than 10 percent over the previous week
• Limit hill work, intervals, and sprint sessions to once or twice a week, with at least 48 hours between them
• After back-to-back hard sessions, schedule an easy jog or a full rest day

Terrain and surfaces

• Mix in track, trail, and artificial turf — all of which absorb shock better than asphalt
• Running the same cambered road in the same direction repeatedly loads one side more than the other; vary your routes

Warmup and calf maintenance

• 5 to 10 minutes of easy jogging plus dynamic stretching before the main workout to raise calf muscle temperature
• Gently foam-roll the gastrocnemius and soleus after training, 1 to 2 minutes per area
• Stay hydrated and get enough protein — 1.2 to 1.6g per kilogram of body weight — to support tendon collagen recovery

Preventing a Recurrence

Achilles tendinopathy has a reputation for coming back, so it's worth keeping up a prevention routine even after the pain has resolved.

Maintenance strength work

• Keep doing eccentric calf raises 2 to 3 times a week for maintenance (you can cut the volume roughly in half)
• Train overall lower-body strength balance, not just the calves — glutes and hamstrings matter here too
• Single-leg balance work for ankle stability: 30-second holds, 3 sets per side

Reviewing your training plan

• Build up training volume deliberately starting 6 to 8 weeks before a race, avoiding sudden spikes
• Introduce one new variable at a time — new shoes, new terrain, or a new training method, never all at once
• If you've had Achilles pain before, be even more conservative with early-season volume increases

Ongoing upkeep

• Keep a consistent pre- and post-training near-infrared wellness routine for the calf (CIRIUS LED Pro or Compact)
• Check running shoe condition and foot alignment every 3 to 6 months
• Watch for large weight swings, since they shift the load on the tendon too

Achilles Tendon Myths vs. Facts

Myth: any pain at all means you need to stop moving completely

Fact: total rest actually blunts the tendon's ability to adapt to load. In a randomized controlled trial, Silbernagel and colleagues (2007, Journal of Orthopaedic & Sports Physical Therapy) found the group that kept training while keeping pain within a manageable range recovered faster and more durably than the group that rested completely.

Myth: more stretching is always better

Fact: in insertional Achilles tendinopathy, aggressive dorsiflexion stretching compresses the area between the heel bone and the tendon and can make symptoms worse. The right amount of stretch range depends on where the pain actually is.

Myth: a thickened tendon on ultrasound means rupture is imminent

Fact: tendon thickening and new blood vessel growth are common findings in chronic tendinopathy and usually don't signal an impending rupture. Symptoms and functional recovery are better guides than the imaging alone.

Myth: once the pain is gone, you can jump straight back to your old training load

Fact: structural remodeling inside the tendon can keep going for weeks or months after pain disappears — which is exactly why the original Alfredson protocol study called for 12 continuous weeks of eccentric work. Returning straight to sprinting or jump training the moment pain stops is a common way this injury comes back.