Fatigue : a case for single subject analysis

Neuromuscular fatigue is relative to the physical capabilities of an individual at a given point in time, and is brought about by a complex combination of central and peripheral factors. Fatigue protocols used in biomechanical research cannot, therefore, be expected to elicit a homogenous response in all research participants. Attempts to establish generalized models for movement outcomes and strategies due to fatigue through descriptive group statistics may therefore be an impractical approach. An alternative approach, single-subject (SS) analysis, may be more appropriate. SS analysis does not imply “case-study” investigation. Rather, it involves an in-depth analysis of individuals to better understand what unique responses, if any, they have in common (Bates, 1996). The aim of this study was to carry out both group and SS analyses on pre- and post- fatigue outcome measures in order to establish how the selected statistical methodology might influence conclusions drawn.