Comprehensive Osteopathic Medical Licensing Examination (COMLEX USA) Practice

Which muscle strength grade indicates full range of motion against gravity?

1. Muscle strength grade 2

2. Muscle strength grade 3

3. Muscle strength grade 4

4. Muscle strength grade 5

The correct answer is: Muscle strength grade 3

Muscle strength grade 3 indicates full range of motion against gravity. This grade reflects that the muscle can produce movement through the entire range of motion without any added resistance. In muscle strength grading, grade 3 is the minimum level necessary to perform activities against the force of gravity but does not account for any external resistance. This grade is pivotal in assessing an individual's ability to perform basic functional movements, which can be crucial in rehabilitation and physical therapy settings. For practical purposes, grade 3 strength is essential for activities such as standing up from a seated position or walking on level ground. The other strength grades denote varying levels of muscle function. Grade 2 indicates that the muscle can move through its range but only when gravity is removed, such as in a horizontal plane. Grade 4 suggests that the muscle can move against some resistance but not maximal, while grade 5 represents normal muscle strength, allowing for full range of motion against gravity along with maximal resistance. Understanding these distinctions can aid in determining appropriate treatment and rehabilitation protocols for patients with muscular weaknesses or injuries.