A crucial experiment is proposed which should decide between Einstein’s interpretation of the Lorentz transformations, where the relativistic effects are explained as the result of space-time transformations, and the alternative interpretation by Lorentz and Poincare, where all the same effects are explained by real physical deformations of bodies in absolute motion through an ether. To break the interaction symmetry with the ether, suitable experiments must involve rapid rotation to violate the relativistic Born rigid body motion criterion. However, if the body-deformation is governed by regular elastic waves, relativity-violating effects are very small with attainable rotational velocities and are therefore probably unobservable. An exceptional situation exists if the deformation is governed by bending waves. In this case, relativity-violating effects would manifest themselves by a very large resonance, greatly amplifying an otherwise minute effect.