Abstract: A pipe coupling for connecting together the ends of two pipes including a tubular casing for fitting around a pipe; tensioning means for tightening the casing around the outer surface of the pipe; and a dynamic axial restraint system comprising at least one resilient gripping ring mounted within the casing for gripping the outer surface of the pipe. The gripping ring includes an outer surface engaging with an inner surface of the casing and adapted to roll against the inner surface of the casing upon axial loading of the pipe; and an inner gripping surface for engaging the outer surface of the pipe. The gripping surface of the resilient gripping ring is adapted such that upon rolling of the outer surface against the inner surface of the tubular casing, the area of the gripping surface in contact with the pipe increases.