Manual muscle testing (MMT) involves grading the strength of individual muscles or muscle groups on a scale based on their ability to perform movements against gravity or resistance. Key aspects of MMT include positioning and stabilizing the patient, demonstrating the movement, applying the appropriate grade of resistance, and documenting the results objectively. MMT is useful for assessing muscle weakness from various neuromuscular and musculoskeletal conditions and monitoring the effectiveness of treatment over time. Contraindications include certain neurological or orthopedic injuries or diseases that could be exacerbated by strength testing.