Pulled Muscle Behind the Knee: Symptoms, Treatment and Recovery

01Anatomy

What lies behind the knee

Behind the knee is a diamond-shaped hollow (the popliteal fossa) crossed by tendons and containing nerves and blood vessels. On the outside are the biceps femoris (lateral hamstring) tendon, on the inside the semimembranosus and semitendinosus tendons, and below the two heads of the gastrocnemius (calf) muscle and the small popliteus muscle. Strains in any of these can feel like a “pulled muscle behind the knee”. See dolor detrás de la rodilla (Spanish), hamstring strain and calf strain.

02Symptoms

Symptoms of a pulled muscle behind the knee

• Sudden pain, sometimes with a pull or pop, during sprinting, jumping, kicking, stretching or lunging.
• Pain and tenderness behind the knee or at the back of the thigh or upper calf.
• Tightness and stiffness, particularly when straightening the knee fully.
• Pain when bending the knee against resistance (hamstring) or rising onto the toes (calf).
• Swelling and bruising that may track down the leg over days.
• Weakness or a feeling of instability in more severe strains.
• Gradual onset in overuse injuries, with morning stiffness.

03Causes

Causes

• Hamstring tendon strain at the knee end, from sprinting, football, rugby or sudden stops. See hamstring tendonitis.
• Gastrocnemius (calf) strain at its upper end behind the knee.
• Popliteus injury, often with other knee ligament injuries.
• Baker’s cyst (a fluid-filled swelling behind the knee), often with knee arthritis or cartilage problems.
• Overuse: running, cycling, hills and sudden increases in training.
• Tight muscles, poor warm-up, fatigue and previous injury.
• Knee conditions such as meniscus tears or arthritis referring pain.
• Deep vein thrombosis, a blood clot, which can look like a strain and must not be missed.

04Compare

Strain, Baker’s cyst or blood clot?

• Muscle or tendon strain: sudden onset with activity, pain with specific movements, bruising, tenderness over the muscle or tendon.
• Baker’s cyst: a swelling or fullness behind the knee, tightness on full bend or straightening, often with arthritis or a history of knee problems; if it ruptures, calf pain and swelling can mimic a clot.
• DVT: calf swelling, warmth, redness and tenderness, often after long travel, surgery, injury or immobility; ultrasound confirms.
• Meniscus or ligament injury: clicking, locking, giving way and joint-line pain.
• If in doubt about swelling and warmth, seek urgent assessment.

05Early

First days: PEACE and LOVE

• Protect: avoid aggravating activity for a few days, without prolonged rest.
• Elevate the leg above the heart when possible.
• Avoid anti-inflammatories in the first days if you can, since inflammation is part of healing; paracetamol is fine for pain.
• Compress with a bandage or sleeve, not too tight.
• Educate: understand that most strains heal well without scans.
• Load: start gentle, pain-free movement as soon as tolerated.
• Optimism, Vascularisation (pain-free cardio such as walking or cycling) and Exercise follow.
• Ice for comfort if you like, but it is not essential.

06Rehab

Rehabilitation exercises

Start when walking is nearly pain-free, and progress as symptoms allow:

• Gentle range of motion: heel slides, bending and straightening the knee within comfort.
• Isometrics: pressing the heel into the floor or a ball with the knee bent at 30–45° for 30–45 seconds.
• Hamstring bridges and curls with a band or on a slide, 2–3 sets of 10.
• Calf raises, double then single leg.
• Gentle hamstring and calf stretches. See hamstring stretches.
• Eccentric work: Nordic or slow lowering exercises later in rehab.
• Balance and hip strengthening.

Progress to jogging and sports only when you have full range of motion, near-normal strength and no pain on hopping.

07Time

How long does recovery take?

• Mild strain (grade 1): 1–3 weeks.
• Moderate strain (grade 2): 3–6 weeks.
• Severe strain or tendon avulsion (grade 3): 3 months or more and sometimes surgery.
• Overuse tendon pain often takes 6–12 weeks with progressive loading.
• Recovery is faster when you load early and avoid long immobilisation.
• Re-injury is common if you return too soon; follow criteria rather than dates.

08Prevent

Preventing recurrences

• Warm up with dynamic movements before sport.
• Build strength in hamstrings, calves and glutes, including eccentric work.
• Increase training load gradually.
• Maintain flexibility and good mobility.
• Manage fatigue and allow recovery between sessions.
• Treat knee arthritis or cartilage problems that can cause Baker’s cysts.
• Stay mobile and hydrated on long journeys to reduce clot risk.

10Cases

Three common situations

A footballer who feels a pull behind the knee while sprinting: likely hamstring tendon strain; PEACE and LOVE and progressive rehab.

An older adult with fullness behind the knee and knee arthritis: consider a Baker’s cyst; see a doctor.

A traveller with a swollen, warm calf after a long flight: urgent assessment for DVT.

11Summary

Key points to remember

A pulled muscle behind the knee is usually a hamstring or calf strain that heals with early gentle loading and progressive strengthening. Do not miss a blood clot or Baker’s cyst: seek urgent care for calf swelling, redness and warmth. Our physiotherapy team can guide your recovery.

This guide is for general information and does not replace an assessment by your own doctor or physiotherapist.