The effect of ageing on shear wave elastography muscle stiffness in adults

Background Skeletal muscle undergoes structural changes with ageing which may alter its biomechanical properties. Shear wave elastography (SWE) may detect these changes by measuring muscle stiffness. Aims To investigate muscle stiffness in healthy young, middle-aged and elderly cohorts using SWE and correlate it with muscle strength and mass. Methods Shear wave velocity (SWV) was measured in the quadriceps, hamstrings and biceps brachii of 26 young (range 20-35 years), 21 middle-aged (40-55) and 30 elderly (77-94) volunteers. The participants performed several muscle tests to evaluate their strength. The One-way ANOVA was used to test the muscle stiffness differences between the groups and the Pearson's correlation coefficient to evaluate the relationship between SWV and muscle strength. Results The overall resting muscle SWV gradually decreased with age but was only significantly reduced in the elderly group (p < 0.001); with the exception of the vastus lateralis SWV where a significant difference was noted (p < 0.05) between young (1.77 m/s), middle-aged (1.64 m/s) and elderly (1.48 m/s). The elderly group had on average 16.5% lower muscle stiffness compared to the young. SWV significantly correlated with muscle mass (r = 0.316), walking time (r = - 0.560), number of chair stands (r = 0.522), handgrip strength (r = 0.436) and isokinetic knee strength (r = 0.640). Sex and BMI did not explain any significant variation in SWV. Conclusions Ageing was associated with a decline in skeletal muscle stiffness which positively correlates with muscle weakness. Further research is needed to evaluate the promising role of SWE as a biomarker for sarcopenia assessment and potential falls risk prediction in elderly individuals.