Characterization of Tendon Mechanics Following Subfailure Damage

Tendon functionality depends on its mechanical properties. Therefore, a tendon’s mechanical properties are essential to define and understand its normal and damaged states. In this study, we characterized porcine digital flexor tendons via stress relaxation and cyclic testing prior to and following overstretch damage. Overstretch damage was induced by pulling tendons to 6.5, 9.0, or 13.0% strain. Both elastic and viscoelastic parameters were measured pre- and post-damage for comparison. Elastic parameters such as the

maximum stress reached during relaxation

and

peak stress during cyclic testing

decreased following damage and viscoelastic parameters such as

stress reduction during relaxation

and

decrease in peak stress from the first to last cycle during cyclic testing

also decreased following damage. Therefore, sub-failure damage induced by overstretching tendons changes both the elastic and viscoelastic properties, and these changes are more pronounced as the damage level increases.