Muscle strains

You will notice strained muscles right away. They are a typical sports injury. That is what makes them different from aching or sore muscles that usually only start to become noticeable one or two days afterwards.

The signs of a strained muscle injury include:

• increasingly painful stiffening of the muscle, especially if you continue to put weight or pressure on it,
• cramp-like pain, and
• an urge to relieve the pain by shaking your leg or stretching.

If the muscle fiber is also torn, the typical signs include:

• a sudden, stabbing pain as if from a needle or knife, and
• involuntarily stopping physical activity because the muscle is painful and can’t take the stress.

There is often a popping or snapping sound when muscle fibers tear. If the tear is deep or the muscle is torn all the way through, the affected leg might give way and cause you to fall.

The pain caused by a torn muscle gets worse if you press on the injured area or stretch the muscle. Visible bruising (hematoma) sometimes develops. Muscle injuries often cause swelling, too.

Because the injured muscle is painful when moved, it is common to change the way you walk to avoid using the muscle. Many people tend to limp if they have injured their thigh to not bend the hip and knee joints as much.

A muscle strain injury can be caused by putting too much weight on the muscle or overextending it. That can happen during fast, sudden or uncontrolled movements.

The front and back thigh muscles (hamstrings) are particularly at risk because they carry out two opposite movements at the same time in the hip and knee joints: When we walk, the hip joint is extended while the knee is bent – and vice versa.

The inside of a muscle contains muscle cells that look like extremely thin threads, which is why they are called muscle fibers. About 250 muscle fibers are held together by connective tissue to form one muscle fascicle. Several of these fascicles are then joined up in bigger bundles of muscle fascicles that are up to half a centimeter thick.

A grade 1 muscle strain causes minor injuries inside the muscle fibers. These microscopic injuries are not visible on ultrasound or magnetic resonance imaging (MRI) scans, but they mean that the muscles no longer work so well.

A grade 2 muscle strain is a more serious injury: Many muscle fibers and one or more of the muscle fascicles are then torn. That often happens where the muscles and tendons meet (at the musculotendinous junction, MTJ).

If the injury is especially deep, the bundles of muscle fascicle and their casing of connective tissue can be torn.

A grade 3 muscle strain means that the muscle is completely torn into separate parts.

In addition to the muscle fibers, the blood vessels are usually damaged, and there is also sometimes damage to the nerve fibers or connective tissue.

The risk factors for a muscle strain include:

• Not warming up properly before training
• Muscles not being trained enough, such as when doing new exercise patterns,
• Tired muscles, possibly at the end of a training session or competitive season, and
• Previous muscle injury, especially within the last four weeks

Your leg muscles are subjected to particularly strong forces when making fast starts and stops, and when suddenly changing directions. That is why the risk of muscle injuries is particularly high in sports with lots of sprints and sudden changes of running direction, like soccer and tennis.

The risk of muscle injuries increases with age.

Muscle sprain injuries are among the most common sports injuries. They make up roughly one third of all sports injuries, but are typically milder injuries like a pulled muscle.

How soon you can start using the injured muscle normally again depends mainly on the severity of the injury, such as whether the muscle is pulled or torn, and how deep the tear is. How well the injury was cared for, like cooling and elevating it and early, cautious mobilization, also affects how quickly it heals.

• If well cared for, pulled muscles usually heal within one week. Light exercises or easy jogging might already be possible without pain after one or two days.
• It usually takes muscles two weeks to recover from a minor muscle fiber tear. Light exercise is possible after about one week.
• If the tear is deeper (muscle fascicle tear) or the tendons or connective tissue casing around the muscle are damaged, it usually takes four to six weeks until you can use the muscle as usual again, sometimes longer. You can start doing light exercise after about four weeks.

These times are a general rule of thumb. It might take longer until you can start exercising and training again without feeling any pain.

Muscle strains usually heal without lasting effects. The body patches torn muscle fibers using new tissue made up of muscle fibers, nerves and blood vessels and repairs the damaged tissue. Substitute tissue provides stability at first, until it is replaced by muscle tissue.

Scar tissue can form on more severe injuries, which may affect how the muscle works. That risk is greater if

• many muscle fascicles are torn, together with their blood vessels. A large, visible bruise is usually a sign of this. The affected area can become severely inflamed if lots of blood collects inside the tear.
• too much pressure is put on the muscle too soon. Structures that have just healed can then tear again, or new tears can form. But carefully increasing the stress put on the muscle can help to prevent scarring. It is important to stop exercising if you feel pain that is more than a mild twinge.

People who take anti-clotting medication have a higher risk of compartment syndrome. That is where too much blood (or fluid) collects in a muscle surrounded by connective tissue. Because it can’t drain out, the pressure increases and damages the muscle tissue and the blood vessels and nerves that supply the muscle. The muscle swells up or stiffens, and is very painful. It can also cause tingling or numbness. Compartment syndrome is a rare, serious complication and requires surgery.

If the pain doesn’t get better after a few days, or you think you might have a serious injury, it is a good idea to see your doctor. Your doctor will first ask about exactly how the injury happened. They can already roughly work out what type of muscle injury it is based on what happened during the accident and the symptoms.

They will then take a closer look at the injury and feel it to check for any bruising, swelling, stiffening or a dent, and to see whether the muscle is tender. Your doctor will also compare the strength and mobility of the injured leg and the uninjured leg, for example.

Ultrasound or MRI scans will sometimes be done to confirm the diagnosis or rule out other injuries such as a complete muscle tear or damage to the tendons or bones.

Four first aid measures to relieve pain and prevent severe bleeding or inflammation reactions in the muscle have been found to be effective. They can be remembered as the R.I.C.E. rule:

• R for rest: Don’t exert your leg too much for one or two days.
• I for ice: Cool the painful area repeatedly using a cold compress or a gel pack, for example. Wrap frozen packs in a cloth or towel to protect your skin.
• C for compression: Use a compression or elastic bandage.
• E for elevate: Raise your leg so that it’s resting higher than your heart.

Muscle strains usually heal on their own. After resting, it’s a good idea to start off with adapted exercises and not to keep your leg still for too long at a time. It’s important that you are able to do the exercises with nearly no pain. Mild twinges aren’t a problem. Your doctor might refer you to a physical therapy practice that can help you to recover and prevent another muscle injury.

Over-the-counter painkillers like acetaminophen (paracetamol) or ibuprofen can be taken to treat the pain for a few days. It is best to ask your doctor or pharmacist if you need painkillers for a longer period of time or you aren’t sure which medications are suitable.

A number of different products and methods are available for treating muscle fiber tears. They include creams, bandages, and taping (using sticky elastic tape called kinesiology tape to reduce muscle tension). It is not clear whether these products and methods speed up healing or relieve pain because there are not enough reliable studies on them.

The same is true of treatments using radiation, laser, ultrasound and electric stimulation. It isn't clear blood plasma injections can speed up a return to sports, either. There are lots of unanswered questions about that treatment, e.g. involving suitable active ingredients and dosage. Steroid injections into the muscle are not recommended.

Surgery is only needed in rare cases. Surgery might be used to treat very deep or complete muscle tears, or if there is a risk of compartment syndrome.

It is best to start with mobilizing exercises about 2 to 5 days after a muscle strain injury, depending on how severe it is. You can talk to your doctor or physical therapist about which exercises are suitable.

The pressure put on the muscle is gradually increased. Along with exercises to improve strength and mobility, exercises to stabilize your torso and improve physical awareness can also be a good idea.

Light training is usually possible soon after a muscle fiber tear. But it can take much longer, often about four weeks, until you can start training again if the muscle fascicles are torn.

Like with all other training, it is important to take care when doing the exercises and not to overstretch the muscle to prevent repeat injury. If you take painkillers in the first few days after the injury, you have to be careful when doing mobilization and training exercises because the medications suppress the pain signals.

The risk of another muscle injury is particularly high in the first few weeks after a muscle strain. But doing enough warm-up before training, slowly getting used to new exercises, and taking a break at the right time when you get tired are already good steps towards reducing the risk of injury.

When people are ill or need medical advice, they usually go to see their family doctor first. You can go directly to an orthopedist or a sports medicine physician if you have a sports-related injury. Information about health care in Germany can help you to navigate the German health care system and find a suitable doctor. You can use this list of questions to prepare for your appointment.