Challenges inherent to t'ai chi research: part I--t'ai chi as a complex multicomponent intervention.

In this, the first of 2 companion papers, we present a framework for viewing t'ai chi as a complex, multicomponent intervention that integrates numerous physical, cognitive, and ritualistic components. We discuss how the richness and complexity of t'ai chi poses challenges related to the traditional distinction between specific versus nonspecific effects, the development and interpretation of valid sham controls, and more generally, to the reductionist causal approach of attributing observed outcomes to single, independent component factors. We also discuss parallels between t'ai chi research and the emerging field of whole systems research, and how t'ai chi research may benefit from the use of an ecologic framework. In a second, companion paper, we discuss additional challenges inherent in defining the t'ai chi intervention itself, and more comprehensively outline the benefits and limitations of commonly used clinical research designs to evaluate the efficacy and safety of t'ai chi.