Muscle stretch injuries are common among athletes. A stretch muscle injury, also known as a muscle strain, is a soft tissue injury that involves a stretching or tearing of muscle or tendon fibers. A sprain is a stretching or tearing injury of a ligament. Although the two conditions may share similar signs and symptoms, they are different injuries and usually have a different prognosis or outlook. Muscle strains may occur anywhere throughout the body.
Anatomy
The human body possesses three distinct muscle types: smooth, cardiac and skeletal. Smooth muscle may be found throughout the body, including the blood vessels, urinary tract and digestive tract. Smooth muscle is usually involuntary, which means that a person has little control over its function. Cardiac muscle, the type of muscle that composes the heart, is also largely involuntary. Skeletal muscle is the muscle tissue that contracts to move various parts of the body. A skeletal muscle, such as the biceps brachii -- the prominent muscle on the front side of the upper arm -- usually possesses a muscle belly and a fibrous tendon or cord that attaches to bone.
Causes
Numerous injuries or conditions can cause a muscle strain or a partial rupture of the fibers composing a skeletal muscle. Muscle strains often manifest during sports or activities in which muscles are required to contract or tighten forcefully. Muscle strains can be caused by sudden, traumatic injuries involving blunt force trauma or overuse injuries from activities that require repetitive motions. Failing to warm up sufficiently prior to activity, weak muscles and previous injuries are all contributing factors to strained muscles.
Symptoms
Symptoms associated with muscle strains largely depend on the cause of the strain, the extent of tissue involved and the type of tissue injured. Common signs and symptoms associated with muscle strains include pain in the injured muscle, swelling in and around the injury site, muscle spasms, decreased active range of motion and reduced flexibility in the injured muscle or segment. Muscle strains are graded on a scale of one to three, with a grade three strain being the most severe.
Risk Factors
Certain risk factors may increase the likelihood of experiencing a muscle strain, including insufficient conditioning, fatigue and an improper warm-up. Lack of conditioning can cause a muscle to weaken, leaving a person's muscles more susceptible to injury. Muscle that are fatigued or tired are less likely to support and stabilize nearby joints, which can increase the risk for musculoskeletal injuries, such as muscle strains and joint derangement. A sufficient warm-up prior to vigorous physical activity improves blood flow to the muscles and increases joint range of motion, making the body's tissues less prone to trauma and tears.
Treatment
Treatment for muscle strains depends on the severity of the injury and the extent of tissue damage a person incurs. Most muscle strains respond well to conservative care methods, such as rest, ice, compression, elevation, activity modification and gentle stretching exercises. In the post-acute phase of recovery -- after the initial symptoms have lessened or subsided -- certain manual medicine techniques, such as instrument-assisted soft tissue mobilization, trigger point therapy and massage therapy, may help speed recovery. Surgery is an uncommon treatment method for muscles strains, unless a person's tendon has avulsed or torn away from the bone into which it attaches.
