Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:The right leg was fastened to a dynamometer (I-KON, Chattanooga Group, Oxfordshire, UK) at a knee angle of 50¬∞, while the other leg rested in an extended position, as previously described (11, 14).
Category: