Reliability of Trapezius Muscle Hardness Measurement: A Comparison between Portable Muscle Hardness Meter and Ultrasound Strain Elastography

Abstract

Prolonged computer work and smartphone use can cause stiffness of the neck and shoulder muscles, including the trapezius muscle. Hence, muscle hardness quantification is clinically beneficial. The present study aimed to examine the reliability of trapezius muscle hardness measurement using a portable muscle hardness meter and ultrasound strain elastography. Overall, 20 healthy young men participated in this study. Prior to measurement, the participant’s subjective symptoms, particularly shoulder muscle stiffness, were rated using an 11-point verbal scale. Furthermore, hardness of the right and left upper trapezius muscles was assessed. In the strain elastography assessment, muscle hardness was evaluated using strain ratio. Results showed that, in quantifying upper trapezius muscle hardness, both portable muscle hardness meter and strain elastography had an excellent intra-tester reliability (>0.9). However, the correlation coefficients between muscle hardness values assessed using a muscle hardness meter and those evaluated with strain elastography did not significantly differ, and the scores for subjective shoulder stiffness did not correspond to muscle hardness values. Therefore, the hardness of the trapezius muscle does not directly reflect the subjective shoulder stiffness. Future studies should thoroughly examine the location of the shoulder stiffness, and check whether it is accompanied by local pain or tenderness.

Is Shear-Wave Elastography a Clinical Severity Indicator of Myofascial Pain Syndrome? An Observational Study

“…However, even if MTrP showed an increased pain sensitivity (lower PPT) compared with control point locations, we did not find stiffness differences between active or latent MTrPs with control points. Our results are consistent with a previous study since it was reported that the trapezius muscle hardness does not directly reflect the subjective shoulder stiffness [29].…”

Clinical features of neck and shoulder pain (<i>Katakori</i>) in Japanese hospital workers

“…The elevated stiffness in symptomatic subjects might suggest the validity of assessing katakoriinduced stiffness among middleaged adults. On the other hand, pain score and disability are reportedly not correlated with stiffness values 11,15,16) . Taş and colleagues point out a wide spectrum in stiffness values that inhibit establishing a correlation between those objective and subjective parameters in 35 symptomatic subjects 16) .…”

Effects of alternating heat and cold stimulation at different cooling rates using a wearable thermo device on shoulder muscle stiffness: a cross-over study

“…Previous studies have shown that individuals with neck or shoulder pain have greater muscle hardness than asymptomatic participants [ 18 , 31 , 32 ]. However, there has been no association reported between muscle hardness and subjective muscle stiffness in individuals without pain [ 19 , 21 ]. While a certain relationship between muscle hardness and pain exists, muscle stiffness and fatigue are more subjective complaints.…”

“…A similar measurement device has been used in previous studies [ 19 , 20 ]. In our previous study, we found the muscle hardness meter to have have excellent intra-tester reliability for the trapezius muscle (ICC 1,5 = 0.992–0.995) [ 21 ]. The portable muscle hardness meter displays values on a scale of 0–100, without units.…”