Muscle Injury Print

Muscle Injury, Dr. Allen F. Anderson, Nashville, Orthopaedic Sports Medicine

Muscle tissue makes up approximately 40% of the body weight of the average person. It is the contraction of muscular tissue that allows our joints to move. Muscle tissue is composed of many fibers, which in turn are composed of many sarcomeres. The sarcomere is the smallest contractile unit, and it is through the contraction of countless numbers of these tiny contractile units that contraction of the muscle occurs.

Muscle Soreness

Pain following a workout, delayed muscle soreness, generally occurs several hours following a strenuous workout. While pain during an exercise is generally metabolic in origin, delayed muscle pain is generally thought to occur from damage to tissues. Delayed onset pain is much more likely to occur when beginning a new exercise program or after radical changes to an existing program. Experimental evidence has proven that exercises that produce very high tensions in the working muscle, such as low rep, high weight training, is much more likely to produce delayed pain than endurance, fatigue producing activities. Also, eccentric contractions, "negatives" are much more commonly associated with delayed pain than concentric exercises.

Delayed onset pain generally occurs several hours following the workout and persists for 1-2 days. It is generally believed that damaged to either the muscle subunits or connective tissue framework of the muscle is the cause of the pain. This pain is usually most intense at the musclotendinous junction of the affected muscle.

Treatment is symptomatic since this is a self-limited process. Simple stretching is often effective in providing temporary relief. Non-steroidal ant-inflammatories and icing are also helpful in reducing the pain. Obviously, rest for the involved muscles will also speed recovery.

Since the pain is generally caused by muscle or tissue damage, it is best to avoid this condition altogether. When initiating a new workout program or changing an existing one, work up to heavy weights slowly. Avoid high weights and "negatives" until your body has had a chance to adjust to the new program. Personal trainers are very helpful in providing a safe structured individual plan.

Muscle Cramps

Muscle cramps generally occur during or immediately following exercise, but may occur even at rest in non-athletic individuals. They can occur in any muscle but most frequently are found in the gastrocnemius complex. Their exact etiology is unknown, but it has long be thought that imbalances in electrolytes, dehydration and poor conditioning contribute to their occurrence, although this is still a matter of debate. When one exercises vigorously, losses of water and salt in sweat can contribute to dehydration and a decrease in the concentrations of sodium, calcium and magnesium. These electrolyte alterations can cause hyperexiteability in the muscles and lead to cramps.

Cramps generally occur in small areas of muscles that are innervated by a single nerve. An aberrant contraction begins in a single fiber and spreads throughout the entire motor unit, causing a painful knot. Treatment consists of stretching the cramped muscle to relax the cramp, replenishing the lost water and electrolytes and proper conditioning.

In non-athletes, medications such as quinine sulfate and chloroquine phosphate, are often used to control the symptoms. However, these are of questionable value in athletes. It is generally accepted that proper hydration and training techniques are the best defense against cramps.

Muscle Lacerations

Lacerations to muscles occur more commonly as a result of trauma than athletics. However, whether a laceration occurs as a result of penetrating trauma or a non-penetrating blow, the treatment and reparative processes are the same. Generally speaking, muscles contract as a direct result of stimulation by nerves. Therefore, any portion of a muscle that becomes isolated from nervous input by lacerations or tears, will be rendered non-functional. The lacerated muscle fibers will heal together with very dense scar tissue, but the neural stimulation will not cross this formidable barrier. Therefore, while the body is able to restore continuity to the injured muscle, the portion of the muscle isolated from its nerve, will most likely remain non-contractile. This results in a strength deficit that is directly proportional to the amount of muscle tissue disrupted.

Treatment of small tears in large muscles is for the most part symptomatic. However, large tears that jeopardize the structural integrity of the muscle or open lacerations can sometimes require reconstruction. Since muscle tissue is not suitable for holding sutures, it can’t be directly repaired. Therefore, the defect is usually bridged by local tissue or connective tissue grafts.

Muscle Strains

Muscle strains are a common problem in sports-medicine and most athletes have been affected by strains at one time or another. Strains are usually caused by an over-loading phenomenon which usually results from the forced stretching of a contracted muscle. Since much more force can be generated during eccentric "negative" exercises, strains are much more commonly caused by eccentric stretches. Muscles most commonly involved are those that cross two joints and are expected to generate large forces rapidly. Examples of these would be the quadriceps, hamstring and gastroc muscles. They are commonly seen in sports requiring bursts of speed, such as track, football, basketball, soccer, etc.

Muscle Injury, Dr. Allen F. Anderson, Nashville, Orthopaedic Sports Medicine, Figure 2

Figure 2

Muscle strains represent a wide variety of injuries from mild inflammation to gross disruption of the muscle. Most strains occurs at the bone or disruption of the muscle-tendon interface. This usually presents as severe swelling, often accompanied by severe pain and ecchymosis in the subcutaneous tissue. Often, the muscle bulges away from the defect when contracted and shows asymmetry compared to the unaffected side. These changes are readily demonstrated by MRI scanning which can pick up even minimal areas of inflammation.

Prevention of muscle injuries is of primary importance in athletics. Stretching and proper warm-up periods are very important in avoiding these injuries. Proper conditioning is also important, since most of these injuries tend to occur when muscles are fatigued.

Treatment includes "RICE" (rest, ice, compression and elevation) immediately and non-steroidal anti-inflammatory drugs. Rehabilitation should begin immediately to regain full range of motion of the affected muscle. Avoidance of sporting activities that could re-injure the damaged tissue is also important. Strengthening programs may resume when pain subsides. The injured athlete may return to sports when full range of motion has been regained and he or she can play with minimal or no discomfort.

Muscle Injury, Dr. Allen F. Anderson, Nashville, Orthopaedic Sports Medicine, Figure 2

Figure 1: Disruption of tissue following injury

Very severe strains that disrupt the continuity of the muscle often require surgical exploration to re-establish continuity and function although this is rare.


© Allen F. Anderson, M.D. 2017