A sharp pull at the front of your hip during a sprint, or a persistent ache when lifting your knee to run, could be a sign of a hip flexor injury. These muscles play an important role in running, kicking and changing direction, making hip flexor strains particularly frustrating for runners and field sport athletes.
The good news is that most hip flexor strains can be managed with appropriate rehabilitation. Understanding what causes them, recognising the symptoms and following a progressive recovery plan can help you return to sport safely.
What Is a Hip Flexor Strain?
The hip flexors are a group of muscles at the front of your hip that help lift your thigh towards your body. They include the iliopsoas and rectus femoris, which are particularly important during high-speed and high-force movements, such as running, sprinting and kicking.
A hip flexor strain occurs when muscle or tendon fibres are overstretched or torn. Injuries are generally classified as:
- Grade 1 (mild): Minor muscle fibre damage, with some discomfort but relatively normal movement. Typically you may not even feel a Grade 1 strain during sport, and only after you cool down will you notice
- Grade 2 (moderate): A partial tear causing pain, weakness and reduced movement. Typically you will feel this during sport, and may need to come off as a result.
- Grade 3 (severe): A complete or near-complete tear that may require specialist assessment. Typically you’ll know immediately if a Grade 3 strain has occurred, and will have to come off as a result.
Even a mild strain can make sprinting, kicking or training uncomfortable.
What Causes Hip Flexor Strains in Runners and Field Sport Athletes?
Hip flexor strains commonly occur during explosive movements that place significant demands on the muscles.
Research by Serner et al. (2018) examining acute groin injuries in athletes identified kicking, sprinting and changes of direction as common injury mechanisms for different hip flexor muscles.
Contributing factors include:
- Sprinting and acceleration: Rapidly driving the leg forward places considerable demands on the hip flexors.
- Kicking: Repeated or powerful kicking movements can strain the rectus femoris, particularly in GAA, soccer and rugby.
- Sudden changes of direction: Cutting and sidestepping place additional demands on the muscles around the hip.
- Increased training loads: Sudden increases in running distance, sprint sessions or training intensity may exceed what the muscles are prepared for.
- Fatigue and previous injury: Inadequate recovery and previous hip or groin problems may contribute to injury risk.
For distance runners, hip flexor pain can also develop gradually following increased mileage, hill running or speed training. Not all pain in this area represents a muscle strain, however, which is why an accurate assessment is important.
Common Symptoms and Diagnosis
Symptoms vary depending on the severity of the injury, but commonly include:
- Pain or a pulling sensation at the front of the hip or upper thigh.
- Discomfort when lifting the knee, climbing stairs or running.
- Tenderness around the front of the hip or groin.
- Pain or weakness when sprinting, kicking or changing direction.
- Bruising or swelling in more significant injuries.
Other conditions, including adductor strains, hip joint problems and bone stress injuries, can cause similar symptoms.
A physiotherapist will assess how the injury occurred, examine hip movement and strength, and perform relevant functional tests.
The Doha agreement on groin pain in athletes (Weir et al., 2015) identifies tenderness and pain during resisted hip flexion as relevant findings when assessing iliopsoas-related groin pain.
Further investigation or imaging may be recommended if the injury appears severe, the diagnosis is uncertain or symptoms are not improving as expected.
Hip Flexor Strain Rehabilitation
Rehabilitation should be tailored to the severity of the injury, your symptoms and the demands of your sport. While every recovery is different, treatment generally progresses through four stages.
1. Early Injury Management
Initially, the aim is to settle pain and protect the injured muscle.
Avoid sprinting, kicking and movements that significantly aggravate symptoms, while maintaining comfortable movement where possible.
The HSE’s guidance on sprains and strains recommends avoiding heat, alcohol and massage for the first couple of days, as well as avoiding ibuprofen for the first 48 hours.
As symptoms improve, gentle movement can be gradually reintroduced.
2. Restoring Movement and Strength
Once pain begins to settle, rehabilitation focuses on restoring comfortable hip movement and rebuilding strength.
Exercises may begin with gentle movement through the affected hip, as well as isometric holds before progressing to resisted hip flexion and more demanding strengthening exercises, such as squats and deadlifts.
A study by Thorborg et al. (2016) found that a six-week resistance-band programme improved hip flexion strength in healthy adults. Although this research did not specifically examine injured athletes, it supports the effectiveness of targeted hip flexor strengthening.
Rehabilitation should also address surrounding muscles, including the glutes, hamstrings, quadriceps and core, as well as aim to maintain current fitness levels, through off-feet and non-provactive cardiovascular training, such as on a stationary bike, or through the use of upper-limb only cardiovascular machines, such as an arm-only assault bike or ski-erg.
3. Returning to Running
As strength and movement improve, running can be gradually reintroduced.
This generally begins with comfortable, steady running before progressing to increased distances, faster speeds, hills and acceleration.
As baseline cardiovascular fitness has been maintained, progression to running should be guided by symptoms, strength and movement quality rather than a fixed timeline.
4. Returning to Sport
Field sport athletes need to prepare for the specific demands of their sport, including straight-line and curved sprinting, accelerating and decelerating, as well as high-speed cutting and change-of-direction, and sport-specific movements, such as kicking and jumping.
Rehabilitation should gradually introduce these movements before progressing to full training and competitive matches.
Readiness to return should consider strength, functional performance, confidence and the ability to complete sport-specific movements without significant symptoms.
How Long Does a Hip Flexor Strain Take to Heal?
Recovery depends on the severity of the injury, the muscles involved and the demands of your sport.
The HSE advises that many sprains and strains begin to feel better within approximately two weeks, although more severe injuries can take considerably longer.
For athletes, feeling comfortable during everyday activities doesn’t necessarily mean the hip is ready for full-speed sprinting or kicking.
Returning too quickly can aggravate symptoms, so a progressive rehabilitation plan is important.
How Can You Reduce the Risk of Hip Flexor Injuries?
While not every injury can be prevented, a few practical habits may help reduce your risk:
- Increase training gradually: Avoid sudden jumps in running mileage, sprinting or kicking intensity. Read our guide to increasing your running distance for more advice.
- Strength train consistently: Build strength through the hip flexors and surrounding muscles. Our Strength Training for Runners page explains why strength work is important.
- Warm up properly: Gradually prepare your body for higher-intensity movements. Programmes such as the GAA 15 are designed to help reduce overall injury risk.
- Allow adequate recovery: Manage training loads, fatigue and rest between demanding sessions. Where possible, try to arrange your training week to allow for 48-72 hours between high-demand sessions, such as hard training sessions, matches and intensive lower body strength & conditioning sessions.
- Address persistent discomfort: Don’t ignore hip pain that repeatedly returns during training.
When Should You See a Physiotherapist?
Consider booking a physiotherapy assessment if hip pain is affecting your running, sprinting or kicking, symptoms keep returning, or you’re unsure how to progress your recovery.
Seek prompt medical assessment for severe pain, an inability to bear weight, significant deformity, numbness or circulation changes. Gradually worsening hip or groin pain in runners, particularly pain at rest or at night, also warrants medical assessment to exclude conditions such as bone stress injuries.
At Next Level Physiotherapy, our sports physiotherapy service focuses on identifying the cause of your symptoms, developing an individual rehabilitation plan and supporting your return to activity.
Appointments are available at our Blarney and Little Island clinics in Cork.
Frequently Asked Questions About Hip Flexor Strains
It depends on the severity of the injury. Some athletes may tolerate gentle running during recovery, but activities that increase pain or cause limping should be avoided until assessed.
Aggressive stretching during the early stages may aggravate the injury. Gentle movement and gradual flexibility work can be introduced as recovery progresses.
Not always. Many injuries can be assessed clinically, but imaging may be recommended if symptoms are severe, the diagnosis is unclear or recovery is not progressing as expected.
Rehabilitation commonly progresses from gentle muscle activation to resisted strengthening and sport-specific exercises. The most appropriate exercises depend on your injury and stage of recovery.