Massive redshift surveys of galaxies beyond the local Universe (i.e.z>0.3) provide an exhaustive probe of the observed acceleration of cosmic expansion. While they have the ability to measure the expansion history H(z) through Baryonic Acoustic Oscillations in the galaxy power spectrum, they can at the same time probe f(z) using the redshift‐space distortions introduced in the observed clustering pattern by galaxy peculiar motions. Coupling these two measurements one can in principle distinguish whether cosmic acceleration is due to a new form of ‘dark energy’ in the cosmic budget, or rather requires a modification of General Relativity. These two radically alternative scenarios are degenerate when considering H(z) alone, as yielded, e.g., by the Hubble diagram of Type Ia supernovae. We review our recent measurements of redshift distortions at z∼ 1 based on the VIMOS VLT Deep Survey “Wide” data and discuss the revived interest on this technique in the context of dark energy. Current results are consistent...