What are muscles made of?
Muscles are made up of lots and lots of muscle cells that are grouped together in bundles. These bundles are held together by layers of fascia (that white sinewy stuff in meat) and the muscle itself is also surrounded by a thick layer of the fascia. The muscle cells all receive a good blood and nerve supply via several arteries, veins, and nerves that thread through the muscle.
Muscles attach to the bones via tendons. Tendons are mainly made up of collagen fibers and they don’t have such a good blood supply compared to muscle tissue.
What happens when you pull or strain a muscle?
When you strain a muscle, you tear some of the muscle fibers. The more fibers you tear, the more serious your injury is and the longer it will take to recover.
The strain may also affect your tendon and the research has shown that any muscle injury where the tendon has also torn usually takes a lot longer to heal.
You will usually also tear some of the blood vessels, which is why you may see a bruise appear a few days after injuring yourself. Not all muscle tears cause visible bruises – you will only see a bruise if the dead blood moves close to the skin before it is absorbed. Once the bleeding stops, it forms a clot that will play an important part in the healing process.
How does the body heal a muscle strain?
The body follows a 3 stage process when it repairs a torn muscle or tendon.
STAGE 1 - Inflammatory Stage
Duration: The inflammatory stage takes about 3 to 5 days to complete.
The first step towards healing is that the bleeding should stop. That is why it is important to stop your running or sport as soon as you pull a muscle. Once the internal bleeding stops, a blood clot forms in that area. Don’t confuse this clot with deep vein thrombosis – they are different things. This clot acts in the same way as a scab does when you cut your skin – it provides the scaffolding for new cells to attach to.
Before the body can start producing new cells, it has to first get rid of the damaged ones. It does this through an inflammatory process where the inflammatory cells absorb and remove the damaged cells. So inflammation is an extremely important part of the healing process and also one of the reasons why you should NOT use anti-inflammatory medication to treat muscle strains. Following the PRICE regime is useful during this stage.
STAGE 2 - Proliferation Stage
Duration: Injuries involving muscle and fascia cells take between 7 and 21 days to complete this stage. Tendons take much longer.
Around day 3 to 5 post-injury, the body starts producing new cells to replace the damaged ones. It uses the blood clot as scaffolding to attach them to. At this stage, the cells are still weak and disorganized. It is important to start introducing some movement and strength training, but it should all be done in the pain-free range and be very gentle.
Here's an overview of which treatments are essential to heal a strained hamstring.
STAGE 3 - Remodelling Stage
Duration: This process starts shortly after the first new cells have formed and, for minor strains, it can finish within 4 weeks. More severe strains, that also involve the tendon, can take many months to fully recover.
All the cells in our muscles and tendons align in a certain direction which correlates to how that specific muscle or tendon functions. For the injured muscle and tendon to fully recover, the new cells have to grow strong and be realigned with the rest of the tissue. This can only be done through a progressive strength training program.
How do you know which stage of healing your injury is in?
To err on the side of caution, assume that the inflammatory phase always lasts 5 days. After that, you don’t really need to know the exact stage of healing in order to choose the right treatment. The important thing is to understand that during the early stages of recovery, your treatment should be focused on protecting the area and not doing exercises and movements that are too forceful. Using pain as a guide can be very useful to get this right.
As your muscle strain recovers, you have to then move to harder exercises and also increase the complexity of the program so that it properly prepares the muscle for the work it will have to do when you play your sport. One of the features of our Exakt Health App is that it guides you through this process. It uses the same functional tests that a physiotherapist would use to decide when your muscle is ready to progress to the next level of strength training or restart your sport.
So how long will your pulled muscle take to heal?
If it’s a mild strain that only involves the muscle tissue, it will likely take 4 to 6 weeks to heal. More severe strains involving mostly the muscle tissue can take 8 to 12 weeks before you can get to full sports. If the tendon is involved your healing time will likely be more than 4 months.