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:Study protocol
 In a previous study (Ega√±a and Green 2005) we tested the eVect of body tilt angle on fatigue during calf exercise (as described in the previous section) that was performed at a high contractile force relative to the maximum (70 %MVC).
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