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.