The application of modulated-temperature programming to thermomechanical analysis affords a method for separating the reversible nature of thermal expansion from irreversible deformation arising from creep under the applied load or changes in dimensions due to relaxation of orientation. Measurements may be made under tension (for thin films and fibres) or compression (for self-supporting specimens). The treatment of data is similar to that employed in modulated-temperature DSC (MTDSC). The superposition of a dynamic load in addition to a modulated-temperature program leads to modulated-temperature dynamic mechanical analysis.