Objective    To provide the biomechanical basis of plantaris tendon for clinical autotransplantation.     Methods    Fifteen plantaris tendons from 8 fresh adult cadavers were cut into 56 segments with about 6 cm lengths in each. The segments were divided into 3 groups: upper

middle

and lower segments. Fifty segments were taken for the tensile test

while the other six segments were loaded under 30 MPa

40 MPa

and 50 MPa respectively. The histologic structure of the tendons was observed under the microscope after presumptive load.     Results    The average limit load

tensile strength and elastic modulus of the plantaris tendon were (83.19±42.52) N

(60.32±21.80) MPa

and (714.83±285.44) MPa respectively. The tensile strength of the lower segments was significant higher than the upper and middle segments.     Conclusion    The biomechanical property of the plantaris tendon is accommodative for autografting.