A groin injury is a strain or tear in one of the five muscles that run along your inner thigh, collectively known as the adductors. These injuries account for roughly 11% of all sports injuries and range from a mild pull that heals in weeks to a severe tear requiring months of recovery. While most common in athletes, groin injuries can happen to anyone during sudden movements or overexertion.
The Muscles Involved
Your groin is made up of five muscles: the adductor longus, adductor brevis, adductor magnus, gracilis, and pectineus. Their job is to pull your leg inward toward the center of your body, a movement called adduction. They also play a major role in balance and stabilization, which is why they’re under so much stress during quick lateral movements, pivoting, and kicking.
The adductor longus is the most commonly injured of the group because of its position and the load it absorbs during explosive movements. All five muscles attach near your pelvis, which is why groin pain often radiates upward into the lower abdomen or downward along the inner thigh.
What Causes a Groin Injury
Groin injuries typically happen during movements that place sudden, high force on the inner thigh muscles. Quick changes of direction, sprinting from a standstill, kicking, and lunging are the most common triggers. Sports involving repeated accelerations, decelerations, and directional changes carry the highest risk. Soccer, ice hockey, football, and tennis are especially notorious.
The underlying mechanism comes down to overload. When the force placed on a muscle exceeds what the tissue can tolerate, fibers stretch beyond their limit and tear. This can happen in a single explosive moment, like planting your foot and twisting, or it can develop gradually through repetitive stress that accumulates over time. In the gradual version, the muscle and its attachment points at the pelvis undergo what researchers describe as subcritical tissue overload, where repeated strain causes damage before the tissue has time to fully recover between sessions.
Risk factors beyond sport include poor flexibility in the hips, weakness in the adductor muscles relative to the outer hip muscles, insufficient warm-up, and a history of previous groin injuries. Prior injury is one of the strongest predictors of future injury because scar tissue is less elastic than the original muscle fibers.
Severity Grades and What They Feel Like
Groin strains are classified into three grades based on how much muscle tissue is damaged.
A Grade 1 (mild) strain means a small number of muscle fibers are overstretched or slightly torn. You’ll feel tightness or a dull ache in your inner thigh, especially when squeezing your legs together or pushing off to change direction. Walking is usually fine, though running or cutting movements will be uncomfortable. Most people can still bear weight without significant pain.
A Grade 2 (moderate) strain involves a partial tear of the muscle. Pain is sharper and more immediate at the time of injury, often accompanied by swelling or bruising along the inner thigh. Walking may be noticeably painful, and activities like climbing stairs, getting in and out of a car, or rolling over in bed can all aggravate it. You’ll likely feel a clear weak spot when trying to squeeze your legs together.
A Grade 3 (severe) strain is a complete or near-complete tear of the muscle. This usually comes with a sudden, sharp pain at the moment of injury, sometimes described as a popping sensation. Bruising and swelling appear quickly. Bearing weight on the affected leg is difficult, and any attempt to engage the inner thigh muscles produces significant pain. In some cases, you can feel a gap or depression in the muscle where the tear occurred.
Recovery Timelines
How long you’re sidelined depends directly on the grade of injury. Grade 1 strains generally heal within 2 to 3 weeks with rest and gradual return to activity. Grade 2 strains take 2 to 3 months because partial tears require more time for the tissue to rebuild and regain strength. Grade 3 strains need 4 months or more, and some may require surgical repair if the muscle is fully torn from its attachment point.
These timelines assume you’re following a structured rehabilitation process. Returning to activity too early is the most common reason groin injuries recur. The pain often resolves before the muscle has regained full strength and flexibility, which creates a false sense of readiness. A good rule of thumb: you should be able to perform the movements that caused the injury, at full intensity, without pain or hesitation before considering yourself recovered.
How It’s Diagnosed
Diagnosis starts with a physical exam. Your doctor will press along the inner thigh muscles to locate the point of tenderness, then ask you to squeeze your legs together against resistance to test for pain and weakness. They’ll also move your hip through its full range of motion to rule out joint problems. Several specific tests assess different structures around the hip and pelvis, including movements that stress the hip joint itself, the sacroiliac joint in your lower back, and the various muscle groups that converge in the groin.
Imaging isn’t always necessary for straightforward strains. But when the diagnosis is unclear, or the injury isn’t improving as expected, an MRI can reveal the exact location and extent of the tear. This is especially useful for distinguishing between a muscle strain and other conditions that cause similar symptoms.
Groin Strain vs. Hernia
One of the most common points of confusion is whether groin pain is a muscle strain or a hernia. The symptoms overlap significantly. Both can cause a dull ache, burning pain, or a feeling of heaviness in the groin area. Harvard Health notes there’s “very little difference in symptoms” between the two, which is why many people struggle to tell them apart.
The key distinguishing feature is physical. An inguinal hernia occurs when fatty tissue or a loop of intestine pushes through a weak spot in the abdominal wall into the groin. This creates a visible or palpable lump that you can often feel when standing or straining. A groin muscle strain does not produce a lump. If you can feel a bulge in your groin area that becomes more prominent when you cough or bear down, that points toward a hernia rather than a muscle injury.
You may also encounter the term “sports hernia,” but this is misleading. A sports hernia is not actually a hernia at all. It’s a strain or tear of the soft tissue in the lower abdomen or groin, without any protrusion through the abdominal wall. The name persists in common usage, but the injury itself is a strain.
Treatment and Rehabilitation
Initial treatment for most groin strains follows a straightforward pattern: protect the injured area, rest from aggravating activities, apply ice to manage swelling, and use compression when helpful. For the first few days, the priority is controlling inflammation and pain. Most people find that lying with a pillow between their knees reduces discomfort at night.
Once the acute pain settles, rehabilitation shifts toward restoring range of motion and rebuilding strength. Early exercises focus on gentle stretching and isometric contractions, where you engage the muscle without actually moving the joint. As healing progresses, exercises become more dynamic, eventually incorporating resistance training, lateral movements, and sport-specific drills. The goal is to gradually reload the muscle so it adapts to higher forces without reinjury.
For Grade 3 tears, particularly those where the muscle has pulled away from its attachment on the pelvis, surgery may be necessary to reattach the tissue. Post-surgical rehabilitation follows a longer, more cautious timeline but generally follows the same progression from gentle movement to full activity.
Prevention Through Strengthening
The most effective way to reduce groin injury risk is targeted strengthening of the adductor muscles. The Copenhagen adduction exercise, a partner-assisted or bench-assisted exercise where you lift your body weight using your inner thigh, has become a standard tool in sports injury prevention programs. Studies evaluating this exercise in real-world settings have found injury risk reductions of up to 41%, though results vary depending on how consistently teams implement the program.
Beyond specific exercises, maintaining a balanced strength ratio between your inner thigh (adductor) and outer hip (abductor) muscles is important. When the outer hip muscles are significantly stronger than the inner thigh muscles, the adductors are more vulnerable during sudden lateral movements. A well-rounded lower body strengthening routine that includes both muscle groups, combined with dynamic warm-ups before activity, provides the most reliable protection.