Viscoelastic properties of cat tendon: effects of time after death and preservation by freezing.

In this study postmortem changes in the character of the stress-strain limit cycle were analyzed for cat extensor communis and extensor lateralis tendons maintained in a stream of Ringer’s solution and loaded with a short series of symmetrical triangular-wave stress cycles. The mechanical behavior of these tendons was compared with that of similar tendons which had been preserved by freezing. It was found that the overall stiffness (average apparent elastic modulus) of these tendons did not change significantly in the first 3 hrs after death and that the shape characteristics of the stress-strain curves changed little under these conditions. Tendons preserved by freezing displayed stress-strain limit cycles similar to those for fresh material. The average moduli for frozen tendons were lower than those from fresh tendons to a degree which was statistically significant.