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

The purpose of this study was to assess both intra- and inter-examiner reliability of manual muscle testing (MMT) within Applied Kinesiology (AK) practice.

Comprehensive searches were conducted in Medline, Scopus, Ebsco, and Embase, alongside manual searches of reference lists, with no date restrictions through October 14, 2023. Only studies applying MMT according to AK principles were included. Methodological quality was assessed using QAREL and Part B of the COSMIN checklist. A qualitative data synthesis was done to analyze reliability data.

From 8,720 initial records, 7 studies met the inclusion criteria. Four were rated as good or very good quality, while 3 were rated as poor or inadequate. Intraexaminer reliability was assessed in 3 studies: 1 demonstrated high reliability (ICC > 0.86), while 2 showed poor reliability (k = -0.14 to 0.29, with 27%-40% agreement). Inter-examiner reliability, evaluated in 6 studies, ranged widely from k = -0.51 to 0.91. A subgroup analysis including only studies that used MMT without additional challenge procedures showed inter-examiner reliability ranging from k = -0.05 to 0.91. The piriformis muscle demonstrated the highest reliability (k = 0.7 to 0.91), while the hamstrings had the lowest (k = -0.07 to 0.24).

The reliability of MMT in AK ranged from nonexistent to very strong, depending on the type of analysis. MMT involving nonmusculoskeletal challenges showed nonexistent reliability and therefore not recommended for clinical use. However, MMT without challenges may be clinically useful, particularly for the deltoid, gluteus maximus, piriformis, and iliopsoas, which demonstrated moderate to very strong reliability.