Manual muscle testing was developed in response to the need to assess muscle strength losses during the polio outbreak in early part of the 20th century. The development of this original method is credited to Wilhelmine Wright and Robert W. Lovett, MD. Wright presented this method in 1912 in the Boston Medical Surgical Journal, and Lovett expanded the description of the testing method in 1916 in the Journal of the American Medical Association. The development of quantifying muscle strength by rating force generated against external resistance was an important development in objectifying assessment methods of the time.
Today, manual muscle testing remains the mainstay of muscular assessment in the medical community, including physical therapy and medical schools. Florence Kendall along with her husband Henry Otis Kendall, refined testing positions in the 1940s. The manual muscle testing taught today incorporates the anti-gravity testing methods of Wright and Lovett, with the refinement of Kendall. Kendall stresses that the skill of the examiner is paramount in accurately grading muscle strength. Trace muscle contractions (grade 1) are discernable from no muscle contraction (grade 0) based on visual inspection and palpation skills of the examiner. Grade 2, poor muscle contraction, is differentiated from grade 3 by position; both grades require full motion but grade 2 is in a gravity eliminated position while grade 3 is anti-gravity. A grade 4 muscle contraction cannot sustain test positions against maximal resistance, while a grade 5 denotes that ability to sustain the test position against maximum resistance. This common clinical method of assessing muscle strength has limitations that today’s technology can overcome.
Copyright © 2015, Oncology Section, American Physical Therapy Association (APTA)
American Physical Therapy Association
Fisher, Mary Insana and Harrington, Shana, "Research Round-up: Manual Muscle Testing" (2015). Physical Therapy Faculty Publications. 47.