Body Representation and Physical Activity: An Investigation into Body Representation and its Mechanism of Change

Abstract

How the body is represented constitutes a vital part in the construction of the sense of self and maintenance of an identity that is unique to each individual. Body representation is a multi-dimensional concept, which includes explicit body-related cognitions, as well as the processing of more unconscious bodily information. These underlying representations can be categorised along the perceptual versus cognitive- affective, and implicit versus explicit dimensions. In other words, the concept of body representation encompasses basic awareness of the bodily status and dimensions, as well as how individuals may think, feel, perceive, and act with regard to their own body. In thinking about the relationship between an individual and their body, its dual characteristic is notable. Not only do we act and interact with the outside world with our body, we also possess cognitions and enact behaviours that are relevant and directed to our own body as an object. During recent years, there has been an increasing interest in the investigation of different aspects of body representation. In particular, the underlying cognitive and neural mechanisms of body representation, as well as how such mechanisms might become disrupted in clinical populations. As yet, however, the overall mechanisms of change in body representation are still poorly understood. An important aspect that has been relatively under-researched is physical activity—since engagement in physical activity generates a lot of relevant sensory information that directly affects the body, which could in turn shape individuals’ body- related cognitions. The main goal of the present dissertation is to investigate changes in body representation in the context of physical activity in a longitudinal context, with focus on a population of healthy adults who have been previously sedentary. We use an updated theoretical framework of body representation, as well as a multimethod account involving innovative methods to disentangle and evaluate changes in different facets of body representation as individuals undergo physical activity training, which include body size perception, body image, and interoception.

The dissertation consists of four sub-components. Study I describes the study protocol of the iReAct study—an interdisciplinary research network aimed at providing a biopsychosocial analysis of the individual response to physical activity—in which the current project is embedded. Study II provides a systematic review of longitudinal studies evaluating the effectiveness of physical activity intervention on improving body representation. Specifically, the review highlighted the need for future studies to consider expanding the theoretical framework to include other aspects of body representation beyond body image. Study III investigates the interrelations between individuals’ affective response to physical activity and two facets of body representation: body image and interoception. Mediation analyses reveals that effects of physical activity on changes in body image post physical activity intervention are independent of individual differences in interoceptive abilities. Study IV provides a comprehensive assessment of body representation in healthy adult samples who routinely engage in high versus low levels of physical activity. Self-report cognitive- affective body image data was combined with experimentally derived parameters obtained via technologically innovative paradigms designed to assess body size perception (i.e., perceptual body representation), as well as interoceptive measures. In sum, the project provides a comprehensive characterisation of different domains of body representation across relevant subsets of the healthy population. It also yields first results on longitudinal changes in body representation and the potential mechanistic interplay between different underlying body-related representations in the context of physical activity.

Conceptually, the current dissertation supports the integrative framework of body representation, in which the different representations are dynamically interacting. We propose that, in order to fully explore the mechanism of change in body representation through the implementation of physical activity intervention, the research question should be investigated in such a way that takes different representations and their mechanistic interplay into account. The present results also emphasise the differences in body representation across relevant sub-groups within the healthy populations, characterised by different levels of physical activity incorporated into their daily routine. Further research is needed to clarify the mechanism with which such differences may arise, taking into account different aspects of physical activity (e.g., exercise type and intensity, engagement characteristic), as well as whether other body- related representations not investigated here might play a role in facilitating the observed differences. Likewise, more empirical evidence is needed in order to clarify the nature of the relationship between long term sedentary behaviour and associated changes in body representation, as better knowledge with regard to these open questions could help us understand the potential role of sedentary behaviour in the development of disturbed body representation, which could further serve to perpetuate the cycle of sedentary behaviour observed to be ever increasing in today’s society.