Apex Performance Centre

Side Strain

Oblique Muscles

Side strain refers to a class of strains and tears in the side abdominal muscles. It’s a common athletic injury, and is particularly common in sports like baseball and hockey where the side muscles are used to swing the bat or shoot the puck.

Also known as back side strain, abdominal side strain, internal oblique strain, and internal oblique tear, side strain is caused by a tear in one of the side abdominal muscles where it attaches to the lower ribs.

What Are Oblique Muscles?

The muscles of the abdomen, shoulder girdle and back attach to the ribs. The internal oblique muscle primarily attaches above, to the ribs and rib cartilages of ribs 8 to 12 and below to the pelvis and strong connective tissue of the lower back. It acts to side bend the trunk and rotate the trunk to the same side.

During contraction or stretch of the internal oblique, tension is placed through the muscle. When this tension is excessive due to too much repetition or high force, the internal oblique muscle can tear. This is known as a side strain. Side strains typically involve tearing of the internal oblique muscle at its rib or rib cartilage insertion on the side of the body.

Causes of Side Strain

A side strain can occur either suddenly, as from a baseball swing, or gradually over time from excessive or repetitive activity.  A side strain typically occurs due to a sudden contraction of the internal oblique muscle when it is in a position of stretch. Baseball players and hockey players are prone to side strains due to the nature of their sports.


People typically experience a sudden, sharp pain or pulling sensation in the side of the chest (in the region of the lower ribs) or abdomen during the activity. Pain typically occurs suddenly, but can also occur gradually over time. In minor cases, the person may be able to continue the activity only to have an increase in symptoms upon cooling down. In more severe cases the person may be unable to continue the activity and will often have to cease sports participation.

It is also common for people to experience pain or stiffness after these activities with rest, especially upon waking in the morning. People with this condition may also experience swelling, muscle spasm, weakness and bruising in the side abdominal region.

Symptoms typically increase on firmly touching the affected region of the muscle or ribs or when performing a side stretch. In more severe cases, deep breathing, laughing, coughing or sneezing may also be painful.

Side Strain Oblique Muscles


With  physiotherapy management, most people with a side strain can make a full recovery  in  4-6 weeks. In more severe cases, recovery may take longer. It is important to note that there is a high recurrence rate with side strains. Often symptoms may appear to resolve within the first couple of weeks only for athletes to re-injury themselves upon prematurely returning to training.

Because of this it is preferable that people with a side strain complete a full rehabilitation program closely guided by their treating physiotherapist, and a thorough fitness test, prior to returning to sport. In rare cases, some people with a side strain may experience ongoing or recurrent symptoms or complications which may require further management.

How Apex Can Help

If you believe you are suffering from a side strain or oblique strain, we can help. The health professionals at the Apex Centre will evaluate your condition and develop a therapy designed to quickly return you to normal activities.

Treatment may include physiotherapy, massage therapy and athletic therapy. We will also work with you to develop a program of exercise and stretching designed to keep the condition from recurring.