2021 Volume 36 Issue 5 Pages 689-698
[Purpose] The purpose of this study was to investigate the effects of proficiency in muscle hardness measurement, which is used as an evaluation in physical therapy, and the use of different equipment types and positioning on the intra-rater and the inter-rater reliabilities. [Participants and Methods] The participants were 12 healthy adult males. Using three types of hardness meter, three experts and three beginners measured the muscle hardness of the lumbar erector spinae, rectus femoris, and triceps brachii in two positions: relaxed and stretched. [Results] For the intra-rater and inter-rater relative reliabilities, a comparison of the average measured values showed they had high reliability, and in the stretched position, the measurement reliability for each muscle tended to be higher for both groups of examiner. For the absolute intra-rater reliability, systematic bias was observed for the youngest examiner measurements in both groups. [Conclusion] Differences in proficiency and positioning influence the measurement reliability of muscle hardness.