Related Experiment Video
Updated: Jun 30, 2026

Biomechanical Characterization of Human Soft Tissues Using Indentation and Tensile Testing
Published on: December 13, 2016
Molecular NMR T2 values can predict cartilage stress-relaxation parameters
Ronald K June1, David P Fyhrie
1UCSD and VA Medical Research Foundation, La Jolla, CA 92093-9111K, USA. rjune@ucsd.edu
Abstract:
Articular cartilage lines synovial joints and functions as a low-friction deformable tissue to enable smooth and stable joint articulation. The objective of this study was to determine the relationships between cartilage stress-relaxation properties and the collagen and GAG NMR transverse relaxation times (T(2)) toward understanding mechanisms of cartilage viscoelasticity. Stress-relaxation tests were performed on both cultured and enzymatically digested bovine cartilage, followed by measurements of both the collagen and GAG T(2) using the Call-Purcell-Meiboom-Gill pulse sequence. The peak and equilibrium stresses were correlated with the GAG T(2), and the stress-relaxation time constant was correlated with the collagen T(2). Multiple linear regression models were successful in using the specific T(2) values to predict the stress-relaxation properties. As a model of osteoarthritis, enzymatic digestion with collagenase and testicular hyaluronidase had weak effects on T(2) values. These data present a complex picture of cartilage mechanical behavior, with cartilage stiffness associated with the GAG T(2) values and the stress-relaxation time constant associated with the collagen T(2).
Related Concept Videos
Atomic Nuclei: Types of Nuclear Relaxation
In spin–lattice or longitudinal relaxation, the excited spins exchange energy with the surrounding lattice as they return to the lower energy level. Among several mechanisms that contribute to spin–lattice relaxation, magnetic dipolar interactions are significant. Here, the excited nucleus transfers energy to a nearby...
¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
2D NMR: Overview of Homonuclear Correlation Techniques
COSY90 is the standard two-dimensional (2D) COSY experiment that...
¹H NMR: Interpreting Distorted and Overlapping Signals
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...
NMR Spectroscopy: Spin–Spin Coupling

