Objective To quantitatively evaluate the stiffness changes of the medial head of gastrocnemius (MG), lateral head of gastrocnemius (LG) and soleus (Sol) at different ankle angles by shear wave elastography (SWE) in healthy young adults.Methods A total of 50 healthy young volunteers were recruited for this study. They were placed in the prone position with the knee fully extended, and the ankle joint angle was changed to dorsiflexion 10°, neutral position 0°, plantarflexion 30° and plantarflexion 50°. SWE was used to measure the hardness of triceps crus, and statistical analysis was performed. Results (1) In the prone position with the knee in full extension, the SWV of the MG was [(5.12±1.13) m/s, (3.98±0.73) m/s, (2.24±0.31) m/s, (2.46±1.38) m/s] and that of the LG was [(4.60±0.83) m/s, (3.57±0.57) m/s, (2.29±0.40) m/s, (2.43±0.51) m/s], at the ankle joints of DF10°, NE0°, PF30°, and PF50°respectively.There was no statistically significant difference in the change of LG stiffness between the PF30° and PF50°groups (P＞0.05).(2) Sol stiffness in ankle DF10°group was greater than that in PF30°and NE0°groups, with statistically significant differences (P < 0.05); Sol stiffness in PF50°group was greater than that in PF30°and NE0°groups, with statistically significant differences (P < 0.01).(3) There was no statistically significant difference in SWV values for the dominant versus non-dominant leg sides under similar ankle joint angles. (4) Both male and female groups exhibited similar trends in calf muscle stiffness changes with varying ankle joint angles; however, passive joint stiffness of MG in males was significantly higher than that in females during NE0°and DF10°ankle positions; similarly, LG showed significantly higher passive joint stiffness in males compared to females during DF10°ankle positions.Conclusions SWE can objectively evaluate the triceps muscle stiffness. The changes of triceps muscle stiffness are related to the ankle joint Angle. Therefore, attention should be paid to the effect of ankle joint Angle on triceps muscle stiffness.