After studying this chapter, the student will understand the following basic principles of this drug class:
The difference between muscle spasm and muscle spasticity
The mechanism of skeletal muscle spasm
Why and when muscle relaxants may be prescribed by a physician
The mechanism of action for drugs that relieve spasms and spasticity
The adverse effects and combined effects of these drugs
It is not uncommon for an athlete to experience muscle strains, trauma, or mild chronic irritation as a result of athletic participation. Sometimes traumatic injury or irritation to muscle tissue has an associated unwanted muscle spasm that can inhibit the progress or participation of an athlete. Trauma-caused muscle spasm typically results in an increase in afferent pain impulses from the traumatized area, which in turn causes an increase in efferent messages from the CNS to the muscle and a resultant chronic tension. Often the athletic trainer uses thermal modalities or other manual techniques to overcome the associated muscle tension. Because the physician, under certain conditions, may treat these symptoms by prescribing a skeletal muscle relaxant, the athletic trainer needs to have a basic understanding of these types of drugs.
Skeletal muscle relaxants can be helpful in managing the symptoms of moderate muscle spasms caused by muscle contusions, strains, and other traumatic muscle injuries. However, it is important to note that there is an ongoing debate in the medical community regarding the effectiveness, or, more correctly, the appropriateness of the use of skeletal muscle relaxants. Some physicians contend that muscle relaxants can be beneficial for short-term muscle spasm, but tend to be overused for patients with chronic pain.6 Many physicians also point out that, in spite of overwhelming evidence that skeletal muscle spasm is nonexistent; they are continually deluged with seductive incentives to prescribe expensive muscle relaxants.5 The writer of a letter to the editor of the Journal of the Canadian Medical Association stated, "There is no proof that pain symptoms or decreased range of motion result directly from abnormality or spasm of muscles."10 These diverse ideas indicate a division in the medical field regarding the use of muscle relaxants in a general sense. Because some team physicians prescribe muscle relaxants to certain athletes, it is important that the athletic trainer be aware of the positive and negative aspects of these drugs. The intent of this chapter is to provide a brief overview of these drugs for the athletic trainer's general awareness of this drug class.
Muscle Spasm and Spasticity
The athletic trainer should understand the difference between muscle spasm and muscle spasticity. The athletic trainer will be exposed more often to muscle spasm because this condition is more commonly a result of irritation or trauma to healthy muscle tissue. Muscle spasm resulting from athletic injury trauma results in a loss of range of motion and increased pain ...