A hip flexor strain is a tear in the muscles at the FRONT of the hip that lift your knee toward your chest. It usually hurts in the crease at the top of the thigh, and most heal in a few weeks with the right exercises.
Typical recovery times:
- Mild strain: about 1 to 3 weeks
- Moderate strain: about 4 to 8 weeks
- Complete tear: several months, and rare
If front-of-hip pain came on WITHOUT a clear injury, or keeps getting worse, it may not be a strain at all. More on that below.
Which muscles are the hip flexors
- Iliopsoas: a deep muscle that runs from the lower spine and inside of the pelvis to the top of the thighbone. It’s the one most often strained
- Rectus femoris: part of the quadriceps. It starts at the front of the pelvis and crosses both the hip and the knee, so kicking and sprinting load it hard
- Smaller helpers, including the muscle at the front and side of the hip and the long thin muscle that crosses the front of the thigh
Symptoms
- Sharp pain or a pulling feeling at the front of the hip or groin at the moment of injury
- Pain lifting the knee, climbing stairs, getting into a car or kicking
- Pain stretching the front of the hip, such as a long stride or lunging
- Tenderness, swelling or bruising at the top of the thigh
- Stiffness after sitting or first thing in the morning
Most strains happen in sprinting, kicking, martial arts, dance and sports with sudden acceleration. A long stretch of sitting doesn’t strain the muscle, but it can leave the hip stiff and achy.
Rehab, stage by stage
- First few days: relative rest, ice for 10 to 15 minutes at a time, and normal walking if it doesn’t make you limp. Avoid stretching hard or kicking
- Early exercises: bridges, gentle heel slides lying on your back, and holding the knee up a little while seated, all within comfort
- Building strength: standing knee lifts with a light band, step-ups, split squats and lunges. Add a gentle stretch at the front of the hip once it no longer hurts to do so
- Getting back to sport: jog, then run faster, then sprint. Kicking and high knees come last
Strengthen the buttock and trunk muscles too. They share the work of steadying the pelvis and take load off the front of the hip.
A strain starts with a clear moment. Front-of-hip pain that crept up on you deserves a second look.
When it’s something else
- Hip labral tear: deep groin pain with clicking or catching, often worse sitting or turning the hip in. See hip labral tear
- Stress fracture of the hip: a crack in the neck of the thighbone from repeated load. Suspect it if you’re a runner or in military training and the pain builds gradually, gets worse with each step and aches at night. It can get much worse if you keep running on it
- An avulsion in teenagers: in young athletes, a sudden pop at the front of the hip while sprinting or kicking can pull a small piece of bone off the pelvis. It needs an X-ray
- A groin strain: pain on the inner thigh when squeezing the knees together points to the adductors. See groin strain
- Snapping or clunking at the front of the hip: often the hip flexor tendon flicking over bone. Usually harmless. See snapping hip
- A hernia: a bulge in the groin that is more obvious when you stand or cough
Front-of-hip pain after hip arthroscopy is also common, and often comes from irritating the hip flexors during early rehab exercises.
For more on grades and home treatment, see the Cleveland Clinic’s guide to hip flexor strain.
Go to the emergency department if
- You can’t put any weight on the leg after a fall or injury
- The leg looks shorter or turned out, especially in an older adult after a fall
- The hip is hot, swollen and very painful and you have a fever
- A groin bulge becomes very painful or discolored, or comes with vomiting
Get it checked if
- You’re a runner with front-of-hip or groin pain that is worse with every step or aches at night. Stop running until it’s checked
- A teenager felt a pop at the front of the hip while sprinting or kicking
- The hip clicks, catches or locks with pain
- You have no clear injury and pain keeps getting worse
- It isn’t improving after 3 to 4 weeks of sensible rehab
A strained hip flexor heals in weeks. Pain that keeps building needs a proper diagnosis.