Overview
The hamstrings are three muscles — biceps femoris, semitendinosus and semimembranosus — that run from the ischial tuberosity (the sitting bone) down the back of the thigh to the knee. A strain is a tear of the muscle or of the junction where muscle meets tendon, graded 1 to 3 by how much fiber is torn. A proximal hamstring avulsion is a different injury in which one or more tendons pull away from the sitting bone itself.
Where the injury sits and how much tissue is involved decide treatment. A grade 1 or 2 strain in the muscle belly is rehabilitated and back to running in weeks. A complete avulsion of two or three tendons does not reattach itself, and in an active patient it is repaired, ideally within a few weeks.
Common Symptoms
- Sudden sharp pain at the back of the thigh while sprinting, kicking or lunging, often with a pop, that stops the activity
- Bruising appearing over 24 to 48 hours, tracking toward the knee in larger tears
- Tenderness at a specific point along the muscle, or high up at the sitting bone in a proximal injury
- Pain sitting on a hard surface, a palpable gap under the buttock crease, or difficulty walking — all of which point to an avulsion
Gradual posterior-thigh pain without an injury is more often referred from the spine (sciatica) or the hip joint itself, where a labral tear or impingement can produce buttock as well as groin pain.
Causes & Risk Factors
Sprinting injuries happen in the late swing phase, when the hamstring is lengthening under maximal load: the mechanism of soccer, football, track and base-running, usually in the biceps femoris of athletes in their 20s and 30s. Proximal avulsions follow a different mechanism — the hip driven into flexion with the knee straight, as in a water-skiing fall or a slip with one leg shooting forward — and are most common in active patients between 40 and 60. The strongest risk factor for a strain is a previous one, and about a third recur when rehabilitation is cut short.
How It Is Diagnosed
Dr. O'Donnell locates the tenderness along the muscle, tests hamstring strength with the knee at 15° and 90° of flexion, and compares flexibility with the other side using the bent-knee stretch test. He palpates the sitting bone for tenderness and for a gap where the tendon should be; a limp with the trunk bent forward and bruising behind the knee raise the suspicion of an avulsion.
X-rays are taken in adolescents, in whom the growth plate at the sitting bone can pull off before the tendon does, and whenever a proximal injury is suspected. MRI grades the injury: it shows how much muscle is involved and, for a proximal injury, how many of the three tendons are torn and how far they have retracted, which is what decides surgery. Out-of-town athletes can upload scans through mymedicalimages.com.
Treatment Options
Non-operative care
Grade 1 and 2 strains, and most partial proximal tendon injuries, are rehabilitated. The first 48 to 72 hours are for ice, compression and relative rest; after that the muscle is moved and loaded early, because prolonged rest produces a shorter, weaker scar. The program progresses from pain-free range of motion and trunk control to eccentric hamstring loading — Nordic curls, single-leg deadlifts, extender and glider exercises — and then to a running progression from jogging to strides to sprinting. Return to sport is granted on criteria, not a date: full pain-free flexibility, strength within 10% of the other side, and pain-free sprinting. Corticosteroid injection into an acute tear is avoided.
Proximal hamstring repair
Surgery is recommended when two or three tendons have pulled completely off the sitting bone with more than about 2 cm of retraction, and for any complete three-tendon avulsion in an active patient. The tendons are reattached with suture anchors through a small incision in the buttock crease, as an outpatient procedure. Repair within the first 4 weeks is easier and recovers better than a late repair, once the tendon has scarred to the sciatic nerve, so a suspected avulsion is imaged promptly. Single-tendon and partial tears are rehabilitated first and repaired only if they remain weak and painful after 3 to 6 months.
Recovery & What to Expect
A grade 1 strain and a repaired avulsion recover on different timelines. The timelines below are conservative general guides; progression is individualized and criteria-based.
| Milestone | Grade 1–2 strain | Proximal avulsion repair |
|---|---|---|
| First phase | Days 0–3: ice, compression, gentle motion | Weeks 0–6: protected weight bearing on crutches; a hip brace limits flexion; no hamstring stretching |
| Motion & early loading | Weeks 1–2: pain-free range, isometrics, trunk control | Weeks 6–12: wean crutches and brace, restore hip motion, isometric then light resisted hamstring work |
| Strengthening | Weeks 2–4: eccentric loading, Nordic curls, deadlifts | Months 3–6: progressive resistance, eccentric loading, bike and elliptical |
| Running | Weeks 3–6: jog to strides to sprint progression | Months 4–6: walk-jog progression once strength is about 80% of the other side |
| Return to sport | Typically 3–8 weeks on strength and sprint criteria | Typically 6–9 months on symmetric strength and sprint testing |
After a strain, desk work and driving continue from the outset. After a repair, desk work is realistic at about 2 weeks with a cushion, and driving waits until you are off crutches and narcotic pain medication, usually around 6 weeks.
Frequently Asked Questions
How long does a pulled hamstring take to heal?
A grade 1 strain is usually back to sport in 1 to 3 weeks and a grade 2 in 3 to 8 weeks, provided the program moves from early motion to eccentric loading and a running progression. Going back before strength and sprinting are pain-free is why hamstrings tear again.
How do I know if my hamstring is torn or just strained?
A strain and a tear are the same injury at different grades. The one that changes the decision is a proximal avulsion: a pop under the buttock, pain sitting on the bone, bruising spreading to the back of the knee, and difficulty walking. Those findings prompt an MRI within the first week, because a complete avulsion is best repaired within 4 weeks.
Do I need surgery for a hamstring tear?
Most do not. Surgery is recommended when two or three tendons have pulled completely off the sitting bone with more than about 2 cm of retraction, or for a complete three-tendon avulsion in an active patient. Muscle-belly tears and single-tendon or partial proximal tears are rehabilitated.
Should I stretch a pulled hamstring?
Not in the first days, and not aggressively at any stage. Early on the muscle is moved gently through a pain-free range; from the second week the emphasis is on lengthening under load — Nordic curls, single-leg deadlifts, extender exercises — which builds a longer, stronger scar than passive stretching does.
When can I run after a hamstring strain?
Jogging typically begins 1 to 3 weeks after a grade 1 or 2 strain, once walking is pain-free, then builds to strides and sprinting over the following 2 to 4 weeks. After a proximal repair, running waits until about 4 months, when strength is around 80% of the other side.
This page is for general education and is not a substitute for a medical evaluation. Treatment recommendations depend on your individual diagnosis and goals. Kevin O'Donnell, MD sees patients from Coral Gables, Miami, Brickell, Pinecrest and Coconut Grove at 475 Biltmore Way, and out-of-town patients by telemedicine.