Reliability of Manual Muscle Testing in Applied Kinesiology: A Systematic Review

Area of Science:

• Chiropractic and Manual Therapies
• Musculoskeletal Assessment
• Clinical Reliability Studies

Background:

• Manual Muscle Testing (MMT) is a common assessment tool in Applied Kinesiology (AK).
• Understanding the reliability of MMT is crucial for its clinical application and validity.
• Previous assessments of MMT reliability in AK have yielded mixed results.

Purpose of the Study:

• To systematically evaluate the intra- and inter-examiner reliability of MMT when applied according to AK principles.
• To synthesize existing evidence on MMT reliability within the AK context.
• To identify factors influencing MMT reliability in AK practice.

Main Methods:

• Conducted comprehensive literature searches across major databases (Medline, Scopus, Ebsco, Embase) up to October 2023.
• Included studies specifically using MMT based on AK principles, assessing methodological quality with QAREL and COSMIN checklists.
• Performed a qualitative data synthesis to analyze the reliability data (intra- and inter-examiner).

Main Results:

• Seven studies met inclusion criteria; 4 were of good/very good quality, 3 were poor/inadequate.
• Intra-examiner reliability varied, with one study showing high reliability (ICC > 0.86) and two showing poor reliability (k = -0.14 to 0.29).
• Inter-examiner reliability showed wide variation (k = -0.51 to 0.91), with the piriformis muscle demonstrating the highest (k = 0.7 to 0.91) and hamstrings the lowest (k = -0.07 to 0.24).

Conclusions:

• The reliability of MMT in AK is highly variable, ranging from nonexistent to very strong.
• MMT involving nonmusculoskeletal challenges demonstrated nonexistent reliability and is not clinically recommended.
• MMT without challenges may be clinically useful for muscles like the deltoid, gluteus maximus, piriformis, and iliopsoas, showing moderate to very strong reliability.