11.7 Muscular Dysfunction
Muscular dysfunction occurs when our muscles do not work properly, making movement harder to achieve. Such dysfunction could present itself as a lack of muscular strength, range of motion (ROM), coordination or control, and can arise from disorders of the muscles themselves, the nerves that control them, or larger conditions that impact the entire body.
The ways in which muscular dysfunction can affect the body include:
Photo by nattanan23, Pixabay License
Image Description
Image illustrating symptoms of neuromuscular or musculoskeletal disorders. On the left, a person holds their elbow in pain, with a red glow emphasizing discomfort. On the right, a list outlines common symptoms including muscle weakness, limited range of motion, impaired coordination, muscular fatigue and decreased endurance, abnormal or “atypical” muscle tone, involuntary movements, reduced independence, pain and discomfort, postural deformities, and impact on vital organs such as the lungs or heart.
Lack of muscular strength
Muscular Dystrophy (MD) is a type of genetic disorder characterized by progressive muscle weakness and muscle wasting due to the absence of specific proteins in the muscle. Although there are several types of muscular dystrophy which vary in symptoms and time of onset, the most common type is Duchenne Muscular Dystrophy (DMD), which primarily affects males during childhood. Over time, this condition leads to symptoms such as difficulty walking, frequent falls, and muscle wasting of skeletal and cardiac muscles.
Range of Motion Restrictions
Rigidity describes when skeletal muscle has increased muscle tone that is continuously resistant (stiff) to passive movement. Rigidity affects both agonist (or working) and antagonist (opposing) muscles equally and is not dependent on the rate at which movement is occurring. Commonly associated with Parkinson’s Disease, for example, rigidity can lead to reduced flexibility and development of contractures, the permanent shortening of muscles and tendons.
Concerns with Coordination and Control
Similar to rigidity, spasticity is also characterized by increased muscle tone but does not impair movement in the same way. Spasticity differs from rigidity in that resistance (or stiffness) increases with faster movement and can exaggerate reflexes. Spasticity is common in a variety of conditions, such as Cerebral Palsy (CP), Multiple Sclerosis (MS), and Spinal Cord Injuries (SCI), and in those who have had a stroke. While symptoms may contribute to range of motion limitations, spasticity mainly impacts an individual’s ability to produce coordinated and controlled movements due to involuntary contractions.
Watch the video “Understanding Spasticity” on WebMD to learn more about spasticity.
