The jump roll by itself is not used as a Spey cast but it is helpful for straightening a fly-line in readiness for a Spey cast but more importantly it is useful for understanding the basic principles of Spey casting and for this reason it should be practised frequently and perfected, casting from both sides of the body. The main elements of the jump roll cast are – lift – place the anchor – form the D-loop – PAUSE - cast forward .
A D-loop is used in Spey casts when there is limited back space, which makes a V-loop impractical.