What Is Achilles Tendonitis?
The Achilles tendon connects the calf muscles to the heel bone and plays an important role when walking, running, jumping and rising onto the toes.
The term Achilles tendonitis is commonly used by patients and in online searches. However, clinicians increasingly use Achilles tendinopathy, because ongoing tendon pain is not always primarily caused by inflammation.
Symptoms may include:
- Pain or tenderness at the back of the ankle
- Stiffness after rest or first thing in the morning
- Pain when walking uphill or climbing stairs
- Discomfort when running or jumping
- Thickening or swelling around the tendon
- Reduced strength when pushing off through the foot
Morning stiffness and pain after rest are commonly reported with Achilles tendinopathy.
Why Might A Night Splint Seem Helpful?
A night splint holds the ankle in a neutral or slightly upward position while you sleep.
In theory, this may:
- Maintain a gentle stretch through the calf
- Limit overnight shortening around the ankle
- Reduce stiffness after rest
- Keep the Achilles tendon in a lengthened position
- Improve comfort during the first few morning steps
Some NHS services may occasionally prescribe night socks or similar devices to create a prolonged stretch through the Achilles tendon overnight. However, that does not mean they are proven to benefit every form of Achilles tendinopathy.
What Does The Research Say?
For midportion Achilles tendinopathy, the evidence does not show a clear additional benefit from wearing a night splint.
A randomised controlled trial compared eccentric exercises alone with eccentric exercises plus a night splint. Adding the splint did not produce better outcomes. A later evidence review also recommended against adding splinting to an eccentric exercise programme.
The updated 2024 clinical practice guideline therefore states that clinicians should not use night splints to improve symptoms in people with midportion Achilles tendinopathy.
This is different from plantar fasciitis, where night splints may be more appropriate for persistent first-step morning heel pain.
What Is Midportion Achilles Tendinopathy?
Midportion Achilles tendinopathy normally causes discomfort several centimetres above the heel bone, along the central portion of the tendon.
Symptoms may include:
- Localised tendon pain
- Morning stiffness
- Thickening of the tendon
- Pain during or after activity
- Reduced tolerance for running or jumping
- Discomfort when pushing off through the foot
The evidence advising against routine night-splint use relates specifically to this midportion presentation.
What About Insertional Achilles Tendinopathy?
Insertional Achilles tendinopathy affects the point where the tendon attaches to the back of the heel bone.
The evidence for night splints in insertional Achilles tendinopathy is limited. This means there is not enough reliable research to conclude that they provide a meaningful benefit.
Insertional pain can also respond differently to stretching. For some people, forcing the ankle upwards may increase compression where the tendon meets the heel.
This is one reason a night splint should not be selected solely because the pain is located around the Achilles tendon.
Are Night Splints Ever Recommended?
A clinician may occasionally recommend a night splint or stretching sock based on an individual assessment.
This might be considered where:
- Significant calf tightness is present
- Morning stiffness is a prominent symptom
- Another condition is also contributing to the pain
- The person has been assessed and given individual instructions
- A particular ankle position is being maintained for a defined reason
This would be an individual clinical decision rather than a routine treatment for Achilles tendinopathy.
What Treatments Are Usually More Important?
Achilles tendinopathy is generally managed through a progressive rehabilitation programme that improves the tendon’s ability to tolerate load.
Management may include:
- Progressive calf-strengthening exercises
- Tendon-loading rehabilitation
- Temporary adjustment of aggravating activities
- Gradual return to walking, running or sport
- Supportive footwear
- Addressing calf weakness or stiffness
- Heel lifts where clinically appropriate
- Review of training volume and recovery
- Physiotherapy assessment where symptoms persist
Complete long-term rest is generally discouraged because prolonged inactivity can reduce calf and tendon capacity. Instead, activities are normally adjusted while strength and loading are gradually rebuilt.
How Long Can Achilles Tendinopathy Take To Improve?
Achilles tendinopathy often improves gradually rather than immediately.
The response depends on factors such as:
- How long symptoms have been present
- The location of the pain
- The amount of tendon loading
- Strength and flexibility
- Sporting or occupational demands
- Footwear
- Consistency with rehabilitation
- Whether the diagnosis is correct
An NHS rehabilitation resource notes that meaningful improvement may take several months when suitable advice and exercises are followed.
This is why treatment should be judged through gradual improvements in function, strength and activity tolerance rather than expecting a passive support to resolve the condition quickly.
Can A Night Splint Make Achilles Pain Worse?
Potentially.
A splint that places the ankle into excessive dorsiflexion may create discomfort, disturb sleep or increase compression around the back of the heel.
Stop using a splint and reassess the fit if it causes:
- Increased Achilles pain
- Sharp pressure around the heel
- Numbness or tingling
- Skin irritation
- Swelling
- Persistent discomfort after removal
- Noticeably worse morning symptoms
A stronger stretch is not automatically more effective.
Night Splints For Achilles Pain vs Plantar Fasciitis
Night splints have different levels of evidence depending on the condition being managed.
Plantar Fasciitis
A night splint may be considered where the main problem is persistent heel pain during the first few steps after getting out of bed.
Achilles Tendinopathy
For midportion Achilles tendinopathy, research has not demonstrated meaningful additional benefit from adding a night splint to an exercise programme, and current guidance recommends against routine use.
This distinction is important because heel and ankle pain should not automatically be treated in the same way.
The Key Takeaway
A night splint can hold the ankle and Achilles tendon in a stretched position, but this does not necessarily make it an effective treatment for Achilles tendinopathy.
For midportion Achilles tendinopathy, current evidence does not support routine night-splint use. Progressive strengthening, suitable load management and an accurate diagnosis are generally more important.
Anyone considering a night splint specifically for Achilles pain should seek professional guidance rather than relying on the product alone.
