A groin strain is an injury or tear to any of the adductor muscles of the thigh. These are the muscles on the inner side of the thigh.

Sudden movements usually trigger an acute groin strain, such as kicking, twisting to change direction while running, or jumping.

Athletes are most at risk for this injury. Groin strains aren’t usually serious, although a severe strain may take a long time to recover from.

Symptoms of a groin strain can range from mild to severe, depending on the degree of the injury. They can include:

  • pain (usually felt in the inner thigh, but located anywhere from the hip to the knee)
  • decreased strength in the upper leg
  • swelling
  • bruising
  • difficulty walking or running without pain
  • snapping sound at the moment of injury

Groin strain is most common among both professional and recreational athletes.

It’s often caused by straining the adductor muscle while kicking, so it’s more common in the athlete’s dominant leg. It can also be caused by turning quickly while running, skating, or jumping.

Movements that require your muscle to both lengthen and contract at the same time usually cause a groin strain. This puts stress on your muscle and can lead it to overstretch or tear.

Although sports are the most common cause, a groin strain can also occur from:

  • falling
  • lifting heavy objects
  • other types of exercise, such as resistance training

Any overuse of a muscle can lead to a long-term strain.

To diagnose whether you have a groin strain, your doctor will first want to know how your injury happened and whether the circumstances indicate a groin strain.

Circumstances include the activity you were doing when the injury happened, your symptoms, and whether you’ve had a similar injury in the past.

Next, your doctor will do a physical examination. This could involve stretching your adductor muscles to determine if stretching is painful, as well as testing the range of motion of your leg.

Any pain you feel during the exam will help your doctor identify where your injury is located.

In addition to identifying the location of the strain, your doctor will evaluate how serious your injury is. There are three degrees of groin strains:

Grade 1

A grade 1 groin strain occurs when the muscle is overstretched or torn, damaging up to 5 percent of the muscle fibers. You may be able to walk without pain, but running, jumping, kicking, or stretching may be painful.

Grade 2

A grade 2 groin strain is a tear that damages a significant percentage of the muscle fibers. This might be painful enough to make walking difficult. It will be painful to bring your thighs together.

Grade 3

A grade 3 groin strain is a tear that goes through most or all of the muscle or tendon. This usually causes a sudden, severe pain at the time when it happens. Using the injured muscle at all will be painful.

There’s usually significant swelling and bruising. You may be able to feel a gap in the muscle when you touch the injury.

Could it be something else?

A groin strain can be confused with other problems. You might experience similar symptoms with:

  • a stress fracture (a hairline break in your pubic bone or femur)
  • bursitis of the hip (inflammation of the sac of fluid in the hip joint)
  • a hip sprain (inflammation or injury to the tendons or muscles of the hip)

Your doctor will often start with an X-ray and follow up with an MRI to confirm the diagnosis and rule out other injuries.

Immediately after injury, the goal of treatment for a groin strain is to reduce pain and swelling. The first few days of treatment follow the protocol for any muscle injury:

Depending on the severity of your strain, you may need additional treatments to speed healing. These could include:

  • physical therapy
  • massage therapy
  • heat and stretching
  • electrotherapy

If you have a grade 3 strain, you may need surgery to repair the torn fibers, especially where the tendon is involved.

The primary risk factor for groin strain is playing a sport that involves kicking, turning suddenly while running, and jumping. Needing to change direction frequently is also a risk factor.

The most common athletes to get groin strain are soccer players and ice hockey players. However, athletes in many sports can be at risk. This includes basketball, football, rugby, skating, tennis, and martial arts.

Among athletes who play these sports, an additional risk factor is how much they practice during offseason.

Athletes who stop training during the offseason are more likely to lose muscle strength and flexibility while they’re not playing. This puts them more at risk of injuries if they begin training without taking the time to build up their muscle strength and flexibility.

Previous groin strain is another risk factor, since the muscle is weakened from a previous injury.

A study in the British Journal of Sports Medicine also found that having a low range of motion in the hip joint is a risk factor for groin strain.

The best way to prevent groin strain is to avoid using the adductor muscle without proper training and preparation. Especially if you play a sport that’s likely to cause groin strain, regularly stretch and strengthen your adductor muscles.

Continue training throughout the year if possible. If you take a break from training, work back up gradually to your former level of activity to avoid straining muscles.

Recovery time for a groin strain injury depends on the degree of the injury.

In general, you can gauge the level of your recovery by your level of pain. As your adductor muscle is recovering, avoid activities that involve pain.

Resume activities gradually. This will enable your muscle to heal fully and prevent you from developing a recurrent groin strain injury.

The length of time you need to recover will also depend on your level of fitness before the injury. There’s no definitive time frame, since it’s different for every individual.

However, as a general guide, you can expect to rest several weeks before you’re able to return to full activities after a groin strain.

Depending on the grade of your strain, here’s estimated recovery times:

  • Grade 1: two to three weeks
  • Grade 2: two to three months
  • Grade 3: four months or more