Reference values for muscle stiffness and asymmetry using myotonometry: a pilot study.

The sample was only 26 healthy adults aged 18 to 29 from an osteopathic medical school, so the ranges may not apply to older adults, people with pain or injury, or different body types. The sex imbalance, 19 males and 7 females, makes female reference ranges less certain. The global stiffness average was a tentative composite of seven specific sites and would not be replicable if different muscles were measured. BMI was not significant in the regression (p=0.077), and the device cannot measure muscles with more than 20 mm of overlying fat. The study did not establish minimal clinically important differences or link stiffness to patient outcomes. Muscle-specific sex differences were inconsistent with the global result, because females had greater stiffness in some muscles and males in others. Asymmetry values were reported, but the study did not test whether asymmetry relates to handedness, pain, or function.

Do not use these values as diagnostic cutoffs for pain or injury. They are preliminary reference ranges from 26 healthy young adults, and the study did not test patients or treatment effects.