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Muscle strain

What is a muscle strain, and how does it occur?

When the fibre in a muscle are overstretched, or injured, we call it a muscle strain. Muscle strains commonly occur when a muscle has been pushed beyond its physical or physiological limits, or injured as a result of overuse e.g., from a repetitive movement.

Basic anatomy:

There are about 600 muscles in the human body. The muscles that first come to mind, are the ones that we can see when we contract an arm or a leg, but there are actually three different types of muscles in the body: smooth, cardiac and skeletal muscle.

  • Smooth muscle can be found in the blood vessels and in the walls of the internal organs. Smooth muscles are not consciously controlled.

  • Cardiac muscle can be found in the walls of the heart. Cardiac muscles are not consciously controlled.

  • Skeletal muscle is attached to our bones and is responsible for the movement of our body. These are the muscles in the body that we consciously control. This blog will focus on muscle strain of skeletal muscles.

How it works on a microscopical level:

A muscle is surrounded by an outer layer of tissue (fascia), which allows it to move smoothly over the surrounding tissues during contraction. Inside each muscle we find bundles of muscle fibres (fascicles) which are further made up of myofibrils. These myofibrils are made up of microscopic units called sarcomeres. The sarcomeres are responsible for muscle contraction. Inside the sarcomere, there are microscopic proteins which pull on each other when they get stimulated by a nerve impulse. When the sarcomeres shorten it results in muscle contraction.

The combination of muscle contraction and relaxation is coordinated through the nervous system. This is what allows us to control our movements and to run, kick and throw.

Grading of a muscle strain:

Muscle strains are often classified into three grades, depending on the severity of muscle fibre damage:

Grade I - Mild A limited number of muscle fibres are effected. There is no decrease in strength and there is a fully active and passive range of motion. Pain and tenderness may be delayed to the next day. Grade II- Moderate Nearly half of muscle fibres torn. Acute and significant pain is accompanied by swelling and a minor decrease in muscle strength. Grade III (severe)

A complete rupture of the muscle. This means either the tendon is separated from the muscle belly, or the muscle belly is actually torn in 2 parts. Severe swelling and pain and a complete loss of function are characteristic of this type of strain.

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Symptoms of muscle strains:

Some symptoms include the following:

  • A sudden onset of symptoms

  • Pain

  • Swelling

  • Decreased range of movement

  • Spasm of neighbouring muscles

  • Muscle weakness

  • Bruising

  • Stiffness

  • Avoidant behaviour e.g., limping


Pain from muscle strains can happen in any muscle, but they’re most common in the lower back, neck, shoulder, and hamstrings, as a result of an ‘event’ (e.g., strained hamstring kicking football) or as a result of accumulative trauma (e.g., overuse or repetitive strain injury)


Mild to moderate strains can be successfully managed at home, with ice, heat, and over the counter pain and anti-inflammatories medication.

Physical therapy may also be used to help address restriction, swelling, pain, biomechanical patterns related to compensation and assist with rehabilitation and return to sport.

Severe strains or tears may require medical treatment such as splints, additional manual therapy and surgery.

How do you know if your muscle strain need medical attention? If the local area feels numb, if you are unable to move your limbs, if there is bleeding or if the pain doesn’t subside after a few days, you should see a doctor as soon as possible. Your doctor will perform a routine physical exam, and if required, order imaging such as an X-ray or MRI, in order to determine the severity of the injury.

What you can do at home:

According to the Mayo Clinic, minor muscle strains can be treated with rest, ice, compression, and elevation (RICE).

(Relative) Rest Avoid the movement that aggravates the pain. Be aware that too much rest can cause muscles to become weak, which can prolong the healing process. After a couple of days, slowly begin to use the affected muscle group, taking care not to overdo it.

Ice Apply ice immediately after injuring your muscle. This will minimize swelling. Don’t put ice directly on your skin as it can lead to frost bite, and skin damage. Instead, make sure you use an ice pack or wrap ice in a towel. Keep the ice on your muscle for about 20 minutes. Repeat every hour on the first day. For the next several days, apply ice for 20 minutes, every four hours.

Compression To reduce swelling, compress the area until swelling reduces. You can use a compression garment or an elastic bandage but be careful not to wrap the area too tightly, as we want to ensure we don’t cut off your blood circulation completely. It is crucial that the blood can flow freely in the vessels, bring oxygen into the cells and flushes out any wastage.

Elevation Whenever possible, keep the injured muscle raised above the level of your heart. Elevation helps to drain excess fluid from the site of injury, which will reduce pain and speed up the healing process.

Anti-inflammatory medication Some people choose to use anti-inflammatories in order to reduce pain, however, this can be a controversial topic. Inflammation is a natural part of the healing process and completely eliminating the natural response is thought to delay the overall healing timeframe. But excessive swelling can impact function which can also delay healing timeframe. Please seek professional assistance from your GP or pharmacist for advice on what is best for you.


After a few days or once the swelling has reduced, apply heat to the muscle several times a day. This will help bring blood circulation to the area and reduce muscle spasms

Gradual return to activity Total immobility can contribute to stiffness and weakness. To counter this, begin light stretching as soon as possible (as guided by pain, function and your chosen health professional). Gradually increase your level of activity to ensure that it is challenging enough to reach your goal and prevent decompensation but incremented to allow your body to recover and adapt.

You’re less likely to develop a strain if your muscles are strong and healthy. Regular exercise can help condition a muscle to have the capability to perform a particular activity, with the resilience to recover injury-free if the activity if more strenuous than expected– this can be applied to both sport and life.

Make sure to warm up before exercising Last but not least, to prevent further injury, when you return to normal activity, make sure you take time to warm up before exercising. This will help increase blood flow to your muscles, priming them for activity.

If you would like any further information on muscle strains or how it can be treated, you can call us at Retrain Health on (02) 6680 7447 or book online at


Retrain Health is based in the Northern Rivers, NSW. From our Byron Bay and Ballina clinics, our team provides a range of quality healthcare services and products. Retrain Health offers osteopathy, remedial massage, strength and conditioning, and PT sessions, with qualified practitioners.

If you are interested in finding out more information or would like to book an appointment, please contact the clinic by phone (02) 6680 7447, send us an email or click here to book an appointment online.

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