Muscle Strain

Muscle strains are one of the most common injuries affecting both athletes and everyday people, causing pain that can range from mild discomfort to severe tears requiring surgery. Understanding how these injuries happen and heal can help you recover safely and prevent future problems.

Table of contents

• What Is a Muscle Strain?
• Types and Grades of Muscle Strains
• Signs and Symptoms
• What Causes Muscle Strains?
• Risk Factors
• How Is a Muscle Strain Diagnosed?
• Treatment Options
• Recovery and Return to Activity
• Prevention
• Possible Complications

pulled muscle

What Is a Muscle Strain?

A muscle strain, also called a pulled muscle, is a tear in your muscle fibers. It is one of the most common soft tissue injuries that can affect anyone, not just athletes.^[1] Muscle strains are currently the leading cause of missed playing time in professional sports like the NFL, but they are just as common among people doing everyday activities.^[3]

Your muscles are made of thousands of small fibers woven together. When you strain a muscle, these strands of fiber are stretched beyond their limit and tear apart.^[1] You can strain a muscle by pulling it too hard or using it too much, which weakens the fibers.^[1]

Think of it like an old bungee cord. New bungee cords have plenty of give and stretch, but if you use one for too long or suddenly jerk on it too hard, the fibers start to pull apart. This is similar to what happens to your muscle fibers during a strain.^[1]

Types and Grades of Muscle Strains

Muscle strains can range from minor to major injuries. Healthcare providers classify them into three grades based on how severe the damage is.^[1]

Grade 1 strain is the mildest type. Only a few muscle fibers are stretched or torn, and there is minimal structural damage. The injured muscle is tender and painful, but it has normal strength. You might experience some discomfort, swelling, and soreness, but in many cases your range of motion is not significantly limited.^[3][5]

Grade 2 strain is a moderate injury with more extensive damage. A greater number of muscle fibers are injured, but the muscle is not completely ruptured. These injuries cause significant muscle pain and tenderness, along with mild swelling, noticeable loss of strength, and sometimes bruising.^[3][5] You may also feel a “knotted-up” sensation and experience muscle spasms.^[7]

Grade 3 strain is the most serious type. This strain tears the muscle all the way through, sometimes causing a “pop” sensation as the muscle rips into two separate pieces or tears away from its tendon (the fibrous tissue that connects muscles to bones).^[5] Grade 3 strains cause complete loss of muscle function, along with considerable pain, swelling, tenderness, and discoloration. You may see an obvious “dent” or “gap” under the skin where the ripped pieces of muscle have come apart.^[1][5]

Healthcare providers also classify muscle strains based on how they develop:^[1]

• Acute muscle strains happen suddenly and cause immediate symptoms. You might pull a muscle with a sudden, forceful movement or by twisting it.
• Chronic muscle strains develop gradually over time, and so do the symptoms. You can gradually tear a muscle by overusing it without giving it enough time to repair.

Signs and Symptoms

Symptoms of a pulled or torn muscle include muscle pain, muscle spasms, bruising, swelling, muscle weakness, and limited range of motion.^[1] You might also feel a “pop” during the injury or see a gap or dent in the shape of the muscle if the tear is severe.^[1]

A torn muscle feels sore when you try to use it. You can usually locate the pain in one spot, and you may be able to connect it to a recent event or activity.^[1] If it’s a chronic muscle strain, you may develop pain gradually over a few days. If it’s an acute muscle strain, you’ll feel pain immediately, and it may even feel like tearing. You may also feel that your muscle has weakened and you can’t use it at all.^[1]

You’ll usually feel a sudden onset of pain as a muscle strain occurs.^[7] The pain or tenderness is especially noticeable after an activity that stretches or violently contracts the muscle, and pain usually increases when you move the muscle but is relieved by rest.^[5]

Strains can happen in any muscle, but they’re most common in your lower back, neck, shoulders, and hamstrings.^[7] Common types of muscle strains include abdominal muscle strain, back strain, groin muscle strain, hip flexor strain, calf muscle strain, and hamstring strain.^[1]

What Causes Muscle Strains?

Muscle strains happen when you tear the fibers of your muscle. This can happen suddenly or gradually.^[1] The injury can occur in one of three places: within the muscle itself, at the junction between the muscle and tendon (which is most common), or in the tendon where it attaches to the bone.^[3]

Common causes of muscle strains include:^[1]

• Acute injuries: Muscle strains are often sports injuries caused by sudden sprinting, twisting, or jumping. However, accidental muscle strains are also common in everyday life.
• Repetitive strain injuries: Repeating the same movement over and over, whether at work or during a recreational activity, can strain your muscles over time.
• Overtraining: Training or working too hard or too long without letting your muscles rest weakens them. If they don’t have a chance to rebuild, they might break instead.
• Undertraining: Low flexibility and strength can cause muscles to strain with ordinary use. Not stretching or warming up before exercise can overstress your muscles before they’re ready.

During activities that require explosive movements, such as pushing off during a sprint or changing directions quickly in sports, the force across the muscle and tendon can be so great that tissues tear, either partially or completely.^[3] These injuries commonly occur during excessive loading of the muscle—that is, when the muscle is contracting while it is elongating.^[3]

Strains are the result of excessive stretch or stretch while the muscle is being activated, not the result of muscle contraction alone.^[4] When the muscle tears, the damage is localized very near the muscle-tendon junction.^[4]

Risk Factors

Some muscles are more likely to tear than others. These are muscles that cross more than one joint and have complex architecture.^[4] Muscles that cross joints often act to restrain other muscles when you move that joint. If the joint moves with too much force, these muscles feel the impact first.^[1]

Muscles that cross two joints, such as the hamstrings (the hip and knee joints), the calf (the knee and ankle joints), and the quadriceps (the hip and knee joints), are the most susceptible to injury.^[3] The hip adductor muscles (also called groin strains) are also commonly affected, though most of those muscles only cross the hip joint.^[3]

Muscles that contract eccentrically are also at higher risk. Eccentric muscles stretch and lengthen when bearing a load, absorbing the impact of the load with controlled movement.^[1]

Factors that can predispose a person to injury include older age, previous muscle injury, less flexibility, lack of strength in the muscle, and fatigue.^[3] Muscle strains occur more commonly when the muscle is not adequately adapted to the demands of the activity, such as starting a new sport or experiencing significant increases in exercise load. This is why they are much more common in training camps than during the regular playing season.^[3]

Participating in contact sports—such as soccer, football, hockey, boxing, and wrestling—can increase your risk of muscle strains.^[2]

How Is a Muscle Strain Diagnosed?

Your doctor will want to know what type of activity triggered your muscle pain and whether there was a pop in the muscle at the time of injury.^[5] The doctor will ask about your symptoms, especially any decrease in muscle strength or any difficulty moving.^[5]

After noting your symptoms and past medical history, your doctor will examine you, checking for muscle tenderness, spasm, weakness, and decreased muscle movement.^[5] During the physical exam, your doctor will check for swelling and points of tenderness. The location and intensity of your pain can help determine the extent and nature of the damage.^[9]

In more severe injuries where the muscle or tendon has been completely ruptured, your doctor may be able to see or feel a defect in the area of injury.^[9] However, swelling in the area may make this difficult to appreciate.^[3]

If the examination points to a mild or moderate muscle strain, you may not need any additional testing. However, if the diagnosis is in doubt, X-rays or magnetic resonance imaging (MRI) scan may be helpful.^[5] Ultrasound often can help distinguish among several different types of soft tissue injuries.^[9]

Treatment Options

Treating muscle strains focuses on minimizing pain and swelling, supporting muscle healing, and preventing further damage.^[18] Mild strains can be successfully treated at home, but severe strains sometimes require surgical repair.^[2]

For immediate self-care of a muscle strain, try the RICE approach—rest, ice, compression, and elevation:^[9]

• Rest: Avoid activities that cause pain, swelling, or discomfort. Rest the strained muscle and do not put weight on it for a day or two. But don’t avoid all physical activity—continue normal activities like getting dressed or walking.^[6][10]
• Ice: Even if you’re seeking medical help, ice the area immediately. Use an ice pack or cold pack for 10 to 20 minutes at a time. Try to do this every 1 to 2 hours for the next 3 days when you are awake. Put a thin cloth between the ice and your skin.^[6][9]
• Compression: To help stop swelling, compress the area with an elastic bandage until the swelling stops. Don’t wrap it too tightly or you may hinder circulation. Begin wrapping at the end farthest from your heart. Loosen the wrap if the pain increases, the area becomes numb, or swelling is occurring below the wrapped area.^[9]
• Elevation: Elevate the injured area above the level of your heart, especially at night, which allows gravity to help reduce swelling. Prop up the sore arm or leg on a pillow when you ice it or anytime you sit or lie down during the next 3 days.^[6][9]

After 2 or 3 days, you can try applying heat to the area that hurts. Apply heat for 10 to 20 minutes at a time, several times a day. You might also try switching between ice and heat.^[6]

Take pain medicines exactly as directed. Anti-inflammatory medicines such as ibuprofen, naproxen, or acetaminophen also help reduce pain and swelling.^[13] Over-the-counter acetaminophen, ibuprofen, or naproxen can provide additional pain relief, unless your doctor has advised against taking these medicines.^[10]

Some doctors recommend avoiding over-the-counter pain medications that can increase your risk of bleeding—such as aspirin, ibuprofen, and naproxen sodium—during the first 48 hours after a muscle strain.^[9]

Massage the muscle or apply topical pain creams containing menthol. The body has trouble experiencing more than one sensation at a time in a single area, so introducing pressure or menthol helps disrupt pain signals.^[10]

Gentle stretching promotes healing by re-establishing the normal length of the muscles. However, don’t overstretch. If you feel worse after stretching one day, do a gentler stretch the next day.^[10] As pain and swelling subside, physical therapy should be initiated to restore flexibility and strength.^[12]

A physical therapist can help you maximize your flexibility and strength.^[9] Do not do anything that makes the pain worse. Return to exercise gradually as you feel better.^[6]

Getting enough sleep is important because this is when your body makes repairs.^[10]

Recovery and Return to Activity

How long a strain lasts depends on the location and severity of the injury.^[5] After injury, the muscle is weaker and at risk for further injury. The force output of the muscle returns over the following days as the muscle undertakes a predictable progression toward tissue healing.^[4]

Symptoms of a mild (Grade 1) strain may heal with no symptoms or some discomfort within a few days, and a doctor may recommend resting for a few days to prevent the strain from worsening.^[7]

Symptoms of a moderate (Grade 2) strain will usually heal within 3 weeks. After 4 weeks, you may be able to slowly return to physical activity.^[7]

A severe (Grade 3) muscle strain takes 3 to 4 months to heal and most often requires a rehabilitation program to return to physical activity.^[7]

Less severe strains can be mistaken for sore muscles initially, since both can be tender and painful, especially with use. You can tell the difference by location and healing time. If the pain is in a large area, such as your entire back, it’s probably due to sore muscles responding to new activity. If the pain is localized to one specific area, that’s a strain. If the pain eases by day three, you probably just have sore muscles. If the pain intensity has increased by day three, you probably have a strained muscle.^[10]

Prevention

Avoiding excessive fatigue and performing adequate warm-up before intense exercise may help prevent muscle strain injury.^[12] Sports medicine professionals often focus on developing balanced exercise regimens that include adequate warm-ups, strengthening exercises, and flexibility work to help reduce the risk of strains.^[18]

Not stretching or warming up before exercise can overstress your muscles before they’re ready.^[1] Low flexibility and strength can cause muscles to strain with ordinary use.^[1]

Possible Complications

While many muscle strains can heal with proper care, untreated strains may lead to complications.^[7] If you have severe muscle pain, see your doctor right away. You might need to immobilize the injured muscle or have it repaired surgically if it has been torn.^[10]

Possible complications include:^[7][18]

• Chronic pain: Persistent pain or discomfort can develop if a strained muscle doesn’t heal correctly, affecting long-term performance and mobility.
• Muscle weakness: Unresolved strains may result in reduced muscle strength, impacting physical abilities.
• Increased risk of re-injury: Without proper treatment, strained muscles are more susceptible to future injuries, particularly if they haven’t regained full strength or flexibility.
• Formation of scar tissue: Muscles that don’t heal properly may develop scar tissue, which can restrict movement and make the area prone to future injury.

Call your doctor or seek immediate medical care if you have new severe pain, your injured limb is cool or pale or changes color, you have tingling, weakness, or numbness in your injured limb, or you cannot move the injured area.^[6]

Watch closely for changes in your health, and be sure to contact your doctor if you cannot put weight on a joint or it feels unsteady when you walk, or if pain and swelling get worse or do not start to get better after 2 days of home treatment.^[6]

Receiving appropriate treatment promptly can help individuals avoid these complications and promote a full recovery, allowing them to return to their activities safely.^[18]