Preece, J Caleb; Seibold, Tanner; Hutchison, Cortland (Brigham Young University)
Faculty Advisor: Feland, J. Brent (Life Sciences, Exercise Science)
BACKGROUND: The recent development of shear-wave elastography (SWE) allows for the quantification of muscle elasticity/stiffness without complex biopsy or dynamometry. To date SWE information is available in younger subjects (typically <30 yrs). Variables such as temperature, joint position, ultrasound probe position and pressure can affect the SWE measurement.
PURPOSE: The purpose of this study was to determine the reliability of SWE measurements of both the medial and lateral heads of the gastrocnemius muscle using 3 different trained ultrasound users.
METHODS: Data was collected from 118 volunteers (participants in the Huntsman World Senior Games) in St. George, Utah, 2019. Subjects (62 males: mean age = 68.9 ± 7.8 yrs, Ht = 177.4 ± 8.1 cm, Wt= 85.4±20 kg; 54 females: mean age = 66.9 ± 8.5 yrs, Ht = 164.4 ± 7.2 cm, Wt= 69.8±18 kg) signed an approved consent form and then lay prone on a treatment table for 3 repeated ultrasonic measurement of SWE of both heads of the gastrocnemius using all three trained research assistants.
ANALYSIS: The three SWE measurements were analyzed using SPSS ver25 for medial and lateral gastrocnemius separately using the reliability analysis function and calculating a two-way mixed model of Intraclass Correlation Coefficient (ICC).
RESULTS & CONCLUSION: Overall, the measurements of SWE were very reliable with both the lateral gastrocnemius (ICC = .985) and the medial gastrocnemius (ICC = .991). Based on our experience in learning SWE measurements there is a significant learning curve to probe positioning and pressure as well as waiting for a stable elastography signal on the ultrasound screen. The high ICC values for these repeated measurements demonstrate that SWE measurement of the gastrocnemius can be reliable and repeatable. These results may not apply to other muscles since size and depth of muscle can also affect SWE signaling.