Psychology of Supplementation in Sport and Exercise: Motivational Antecedents and Biobehavioral Outcomes

Abstract

Research concerning the physiological and biobehavioral effects of supplements commonly used in sport or exercise settings has multiplied rapidly over the last decade. However, less attention has been directed to understanding the motivational pathways leading to sport and exercise supplement use. This chapter summarizes known usage rates for sport/fitness supplements and describes motivational theories and constructs that may be of use for understanding individuals’ use of these substances. In this respect, we contend that researchers should consider behavioral approaches, the theory of planned behavior, balance theory, achievement goal theory, social physique anxiety, and muscle dysmorphia as useful for developing an understanding of the psychological influences on supplement use. For some of the latter theories/constructs, research has already shown support for their explanatory abilities, whereas research is scant and the utility for understanding sport/exercise supplement use is yet to be determined for many of the theories. In addition to describing the motivation behind supplement use, this chapter summarizes the biobehavioral effects of a select group of supplements commonly used to improve performance, fitness, or health. Specifically, we consider psychobiological effects of caffeine, creatine, Ginkgo biloba, and St. John’s wort related to enhanced arousal, improved memory and cognition, enhanced brain function and protection, and reduced depression. There is promising initial evidence for the efficacy of these compounds in producing favorable psychological outcomes, although certain shortcomings of many studies on these compounds must be taken into account before reaching definitive conclusions.