An extendable hand control for a stretcher undercarriage (10) which has height adjustable legs (11, 12). It comprises a handle (19) fitted to an end of a tube (20), slidable within an undercarriage frame member (21). The handle has an associated lever (15) which operates a control cable (14) for adjusting the height of the height adjustable legs (11, 12). The arrangement includes a locking bar (26) within the slidable tube (20) which sets the maximum extendable position of the handle and the fully retractable position of the handle.