- 1 What is a Muscle Strain?
- 2 Muscle Anatomy and Physiology
- 3 Muscle Strain Causes
- 4 Muscle Strain Symptoms
- 5 Types of Muscle Tear
- 6 Common Sites of Muscle Tear
- 7 Muscle Strain Treatment
- 8 Muscle Strain Prevention
What is a Muscle Strain?
Also known as torn or pulled muscle, a muscle strain is a condition wherein muscle fibers rip or tear . This injury results when there is overstretching of the muscle or it has been forcefully and quickly contracted . Its occurrences differ from case to case; some may develop either partial or complete tearing of the muscle fibers .
Picture 1: Muscle Strain
Muscle Anatomy and Physiology
Muscles function mainly to aid the bones for movement. The muscle is described as a sack or tube which has specialized elastic tissues. These tissues can shorten or stretch. Attached to the bone is the tendon. Tendons are the portion where the end of the muscles becomes solid. As the muscle shortens or contracts, the tendon is pulled. Then, the bone is moved along with it. 
Also, to understand further about how the muscle performs its functions, it is a must to know more about its inner structure. Aside from the tendons on each end of the muscles, there is the structure called fascicles. The fascicles are bundles of fibers located just beneath the outer sheath of the muscles.
When the muscles contract, the linked microscopic parts of these fascicles slide either apart or together. If the microscopic parts slide together, muscle shortening occurs. This leads to joint movement in one direction. On the other hand, when these parts slide apart, muscle lengthening happens. This results to joint movement in the opposite direction.
Muscle coordination is controlled by the brain which allows the performance of complex movements such as running. 
Picture 2: Anatomy of Muscles
Muscle Strain Causes
Muscle strain occurs when the muscle fibers (softer part), excessively pulls and stretches. In some cases, the muscle fibers can even rip or tear apart . This condition commonly occurs due to:
- Colliding with other objects
- Falls 
2. Sports and Exercise
- Improper or no warm up before exercise
- Performing high-speed activities like sprinting and tennis
- Contact sports like basketball, football
- Uncoordinated manner of movements, especially in running or kicking [1, 5]
- Weakened, tired, or inflexible muscle
- Improper body mechanics such as in lifting heavy objects
- Lack or regular exercises [1, 3, 5]
Picture 3: Illustration of Muscle Strain or Pulled Muscle
Muscle Strain Symptoms
The severity of muscle strain dictates what symptoms will occur. The symptoms of this condition include:
- Pain and tenderness at the site of injury. This comes after the activity that caused the overstretching or over-contracting of the muscle. This is aggravated with movement and relieved by rest.
- Swelling of the affected site
- Discoloration or bruising due to the damage of the small blood vessels located at the location of injury
- Snapping or popping of the muscle involved
- Muscle weakness and difficulty of movement at the injured limb
- Muscle spasm or cramp
- Defect of the outline of the muscle
- In severe cases, there may be complete loss of function [3, 5]
Types of Muscle Tear
The various types of muscle tears are classified into three based on the severity of the torn muscle as follows:
First Grade Muscle Strain
This is also known as mild muscle strain. This condition involves the limited tearing and stretching of the affected muscle fibers. Also, there are only few fibers (less than 5%) of muscle which are torn or ripped. This is characterized by:
- Normal strength but with limited movement
- Pain at the site of injury
- Feeling of knotted up muscles
- Heals in a span of 2 to 3 weeks of rest
Second Grade Muscle Strain
Also referred to moderate degree of muscle strain, this involves the injury of more muscle fibers. Though the muscles are damaged, they are not extensively ruptured. It has characteristics of:
- More severe pain felt
- Bruising and swelling
- Decreased muscle strength
- Takes 4 to 6 weeks of rest to heal
Third Grade Muscle Strain
This is termed as the severe muscle strain. It is defined as the complete rupture or tearing of the muscle fibers. In this degree, the muscle fibers are torn away from the tendon. It is characterized by:
- Popping or snapping sensation at the time of injury
- Swelling and discoloration
- Pain and tenderness of the affected site
- Gap or dent under the affected skin where the torn pieces of muscles are located
- In more severe cases, there is complete loss of function
- Rehabilitation time takes 3 months [1, 4, 5]
Common Sites of Muscle Tear
Muscle tear is not restricted to any particular muscle or group of muscles. It can be experienced in any part of the body. However, there are certain body parts that are more susceptible to muscle tears. The commonly seen location of muscle injuries include:
- Abdominal muscles
Picture 4: Abdominal Muscle Strain
- Adductor muscles: The strains in these muscles occur due to sports like football where turning activities are commonly done.
- Elbow and forearm muscles: The strains in these muscles involve the Golfer’s elbow (medial epicondylitis), tennis elbow (lateral epicondylitits), and wrist tendonitis
- Gastrocnemius and soleus muscles: These muscles are located at the calf. Usually, in this case, there is rupture of the Achilles tendon.
Picture 5: Gastrocnemius and Soleus Muscles
- Hamstring muscles: These are muscles located at the back of the leg which are connected to hip and knee joints. These are active in activities such as running or sprinting.
- Hip flexor muscles: Mainly responsible for kicking, these are located at the front portion of the hip.
- Lumbar muscles or lower back muscles
- Quadriceps: These are found at the front of the thigh
- Rotator cuff at the shoulder [1, 2, 4]
Picture 6: Rotator cuff muscle strain
Muscle Strain Treatment
First Aid Treatment
This is the first-line or first-aid treatment for conditions such as muscle strains. The main goal of this is to control the bleeding within the tissue muscles. This includes:
- Protection: Protect the site of injury through applying a dressing or clean cloth, especially when bleeding. This is to prevent possible further damage.
- Rest: This is essential to optimize healing process.
- Ice: Application of cold compress is advised to minimize swelling at the affected site. This should be done not more than 20 minutes.
- Compression: This is done by wrapping the muscle strained area with soft wrapped bandage to prevent or minimize swelling.
- Elevation: Lift the affected area above the level of the heart. This is to avoid pooling of blood at the affected area. [4, 6]
Picture 7: First Aid for Muscle Strain
1. Pain relievers
- Over the counter drugs such as acetaminophen (Tylenol)
2. Anti-inflammatory medicines
- Given to reduce swelling
- Aleve, Viox, Celebrex, Motrin, Ibuprofen [1, 7]
1. Cold Compression Therapy
- This is done by applying cold compress after three days following the injury. This is advised to relieve the pain and reduce swelling of the injury site. Always remember that the ice pack or cold compress should not be applied directly to the injured area. [4, 6]
This is a rehabilitation program which includes activities and other treatment modalities to promote restoration of the body’s functions.
- Transcutaneous Electrical Nerve Stimulation (TENS)
- Therapeutic ultrasound
- Use of brace or walking aid 
- This is a treatment option for patients with more severe cases of ruptured muscle or torn ligament. 
Muscle Strain Prevention
Warm Up Exercises
- According to various studies, it has been proven that warming up prior to exercises can lessen the risk of having muscle strains. This is due to the fact that the muscles can be stretched easily if warmed up or if the tissue temperature is increased.
- It is recommended to perform warm-up exercises for about twenty minutes. It should be started gently, then, progressing to full pace.
- Example of warm-up exercises are jogging or walking. [1, 4]
Cool down exercises
- After performing exercises, cooling down is required. This is to enhance the effects of the exercise regimen and aid in the elimination of the body’s waste products. Cooling down is performed by stretching after exercising. 
Maintain and enhance muscle flexibility and strength
- By performing this, the risk of muscle strains is lessened. Muscle strength enables the body to withstand the activities of the body. Also, this decreases the performance of uncoordinated movements. 
- Maintain normal body weight: It has been known that being overweight or obese can add to the tension in the muscles. This increases stress in body parts such as back and legs.
- Diet: A person’s diet has an influence with the muscle health. A diet adequate in carbohydrates will supply the muscles enough energy to perform muscle contractions. If the body run out of energy or fuel, fatigue may occur. Fatigue of the muscles will lead to occurrence of injury. Fluids are also advised to replenish the body. 
Proper body mechanics
- Use proper body mechanics or technique when carrying out activities such as lifting heavy objects.
- Maintain good body posture when standing and sitting.