"extreme rigidity" is a correct and usable term in written English.
You can use it when referring to a situation or person that is overly strict and inflexible. For example, "His extreme rigidity made it difficult for us to find a compromise."
Accredited journalists have recently protested the White House's extreme rigidity.
PVC had been prepared as early as 1872, but commercial application of the polymer was limited by its extreme rigidity.
Malignant hyperthermia is a metabolic muscle disease characterized by high fever and extreme rigidity of muscles, usually caused by certain anesthetics or muscle-relaxant medications given during surgery.
Even a sympathetic reading of Alceste can't deny his extreme rigidity, or the darkness of his worldview; he has been compared to Hamlet as a truth-teller in a house of deceptive fools.
And in triggering the euro-zone crisis, the extreme rigidity and non-liberalism of southern European societies, economies and political systems, has surely played as much role as any "neoliberal" crusade.
This behaviour is thought to arise from the extreme rigidity of the backbone as well as the particular way in which the alkyl side chains extend from the biphenyl unit.
As long as the Republican Party is dominated by leaders of extreme ideological rigidity, and they escape the blame that they deserve, the dysfunctional situation in Congress will continue.
Composites are high performance advanced materials with a growing applicability due to their extreme strength, rigidity to weight ratios.
Instead, the parties demand extremism and rigidity.
Two competing hypotheses exist: the rigidity-of-the-right hypothesis (i.e., conservatives are dogmatic) and the ideological-extremism hypothesis (i.e., extreme views on both sides predict dogmatism).
PD is a neuronal degeneration of dopaminergic neurons located in substantia nigra pars compacta (SNpc) and the PD patients often show increasing muscle rigidity, resting tremors, bradykinesia, and, in extreme cases, a nearly complete loss of movement.
