Hip flexor strain: symptoms, rehab and return to sport

What a hip flexor strain is

The hip flexors are the muscles that bring your thigh up towards your body. The main ones are iliopsoas, which runs from the lower spine and pelvis to the top of the thigh bone, and rectus femoris, one of the quadriceps, which crosses both the hip and the knee. A strain is damage to some of the muscle or tendon fibres, graded from mild (a few fibres) to severe (a large or complete tear).

Most gym and sport-related hip flexor strains are mild or moderate, with the muscle overstretched or overloaded during a fast movement. The good news is that muscle has a rich blood supply and heals well when it is loaded sensibly.

How it happens and who gets it

Hip flexor strains are common in football, rugby, martial arts, sprinting and any sport with kicking or rapid changes of direction. In the gym they can happen with sprint work, high knees, box jumps, mountain climbers or hanging knee raises, particularly when fatigued or poorly warmed up. Rectus femoris strains are typical when kicking a ball hard.

• A sudden increase in sprinting or explosive work
• Inadequate warm-up before fast movements
• Fatigue late in a session or match
• A previous strain on the same side
• Tight, weak hip flexors from long hours sitting, combined with bursts of intense activity

Teenagers are a special case. Before the growth plates close, a sudden forceful kick or sprint can pull off a small piece of bone where the tendon attaches (an avulsion fracture), rather than straining the muscle. A pop and sudden pain in a young athlete should be checked with an X-ray.

Typical symptoms

• Sudden pain at the front of the hip or top of the thigh during a fast movement
• Pain lifting the knee, such as climbing stairs or getting into the car
• Pain when kicking, sprinting or doing high knees
• Tenderness when pressing on the front of the hip
• Bruising or swelling in more significant strains
• Discomfort stretching the front of the hip, for example in a lunge

A dull ache that has built slowly without any specific moment of injury is less typical of a strain and may point towards the hip joint, a tendon problem or a stress reaction, which is why an assessment is useful if it is not following the usual pattern.

What a physio assessment looks at

Your physio will ask exactly how the injury happened and test the strength and length of the hip flexors, feel for the tender area, and check the hip joint, groin and lower back. They will also consider other causes of pain in this area, such as the hip joint itself, a hernia or a stress fracture of the hip.

Stress fractures of the femoral neck are uncommon but important. They are more likely in distance runners who have increased mileage, and in people with low energy availability or low bone density. Groin pain that worsens with running and progresses to pain at rest or hopping needs a medical assessment and imaging.

What usually helps

Research on muscle strains consistently shows that starting gentle, pain-guided loading within the first few days tends to speed recovery compared with prolonged rest. For the first 48 to 72 hours, avoid sprinting and kicking, keep walking within comfort and use ice or compression if it helps with pain.

Rehab then progresses through stages: isometric holds, controlled hip flexion with bodyweight and bands, heavier strengthening, running drills, and finally sprinting and kicking at full speed. Each stage is added when the previous one is comfortable. Manual therapy may help with pain and stiffness around the hip but is secondary to the loading programme.

What you can start with at home

1. Isometric hip flexion: sitting, press your knee up into your hand without moving for 20 to 30 seconds, 4 to 5 times, at a comfortable effort.
2. The dead bug for controlled hip flexion and trunk control, 2 to 3 sets of 8 each side.
3. Standing banded marches, 2 to 3 sets of 10 each side.
4. Gentle hip flexor stretch in a half-kneeling position, only once it is no longer sore to stretch, 30 seconds each side.
5. Walking and easy cycling to keep the leg moving.

Later-stage exercises such as hanging knee raises, sled work, and running drills are added as symptoms allow. Our guide to returning to running after injury explains how to rebuild speed safely.

Recovery time and when to get help

Mild strains often settle within 1 to 3 weeks, moderate strains commonly take 3 to 6 weeks, and severe or tendon injuries can take longer and may need a specialist opinion. The biggest risk is returning to sprinting and kicking too early. If you want a structured plan, the on-site physio at Lycan Strength can help, with 20% off for members; book a physio appointment online.

Once you are back, keep some hip flexor and trunk strengthening in your weekly training and build sprint and plyometric volume gradually. A previous strain raises the chance of another, so the final stage of rehab is really the start of prevention.

• Go to A&E if you cannot bear weight after an injury or fall.
• See a GP or physio promptly if a teenager felt a pop at the front of the hip, as an X-ray may be needed.
• See a GP promptly if groin or hip pain gets worse with running and you have pain at rest, at night or when hopping.
• Call NHS 111 or see a GP urgently if you have fever, a hot, swollen hip, or a painful groin lump.

Questions