Abstract:ObjectiveTo evaluate the effect of the knee and ankle joint angles on the stiffness of triceps surae in healthy men by shear wave elastography (SWE). MethodsTwenty male healthy volunteers who underwent physical examination in Guangdong Provincial Hospital of Chinese Medicine from January 2021 to June 2021 were collected. Under the condition of full knee extension (0 °) or flexion (90 °), SWE was used to assess the muscle stiffness at 25° dorsiflexion, 0° and 50° plantar flexion of the ankle. ResultsThe stiffness of medial head of gastrocnemius(MG), lateral head of gastrocnemius(LG) and soleus (Sol) in knee extension position was significantly higher than that in knee flexion position at different ankle angles (P<0.05). When the knee was in the straight position, with the ankle dorsi flexion angle increased, the stiffness of MG and LG increased(P<0.05), but there was no significant difference in the hardness of Sol at 0° and 25° dorsiflexion of ankle (P>0.05). When knee flexion was 90°, only LG and sol stiffness increased with the increase of ankle dorsiflexion angle (P<0.01). When the knee was in the straight position, the hardness of Sol was significantly higher than that of MG and LG at 0° and 50 ° plantar flexion of ankle (P<0.01); when the ankle dorsi flexion was 25°, only the hardness difference between LG and Sol was statistically significant (P<0.05). When knee flexion was 90°, there was significant difference in stiffness among MG, LG and Sol only at 25° dorsal flexion of ankle (P<0.05). ConclusionChanges in the angles of the knee and ankle joints can cause non-uniform changes in the muscle stiffness of the triceps surae. The effect of different joint angles on the measurement results is considered in the assessment of muscle stiffness using SWE.