Effects of Imagery on Perceived Exertion, Attention, and Exercise Adherence

IIn recent years, much research effort was devoted to delineate the effects of attentional strategies on exercise-related perceptions and adherence (Basevitch et al., 2011; Connolly & Tenenbaum, 2010; Razon et al., 2010; Razon et al., 2011). Results from these studies paralleled the previous ones suggesting that both associative and dissociative strategies are beneficial, albeit in distinct ways depending on task-characteristics (Lind, Welch, & Ekkekakis, 2009). Less clear, however, remained the extent to which the use of attentional strategies may contribute to design innovative solutions for the primary public health concern of the 21st century; physical inactivity (Blair, 2009). From a dose-response perspective, exercise intensity is a major mediator of physical activity adherence (Ekkekakis, Backhouse, Gray, & Lind, 2008). Specifically, as the workload intensity (and/or time spent on task) increases, the distractive properties of the dissociative strategies are compromised (Lind et. al., 2009; Tenenbaum, 2001), which partly explains the decrease in the perceived exercise-pleasantness (Ekkekakis et al., 2008), and the subsequent ending of the applied effort (Pandolf, 1978). Most recently, the use of cognitive approaches, including imagery use were shown beneficial in allowing distraction from task (Razon et al., 2010; Razon et al., 2011). The current study attempted to investigate the effectiveness of differential imagery use on (1) the perception of exertion and allocation of attention focus, (2) task adherence, and (3) the physiological parameters inherent in physical effort. It was hhypothesized that (1) dissociative imagery would enable reduced perception of exertion and extended distraction from task, (2) associative imagery would prolong time on task, and (3) imagery in general would aid motivation and task-perseverance. 45 students participated in the study. Using a stratified random assignment protocol, 15 participants were assigned to each of the following conditions: 1) dissociative imagery, 2) associative imagery, and 3) no imagery. At session one, participants were first tested for maximal oxygen consumption (VO2 max) to later perform a handgrip squeezing task at 30% maximal contraction value to volitional fatigue. At session two, participants performed a cycling task at 10% above anaerobic threshold (AT) to volitional fatigue. During task performance, participants assigned to dissociative imagery condition used dissociative imagery while their counterparts assigned to associative imagery condition used associative imagery. For both task, participants' rates of perceives exertion (RPE), attention focus, and time on task was recorded. Additionally, on the cycling task, participants' lactate accumulation (LA) ,and heart rate (HR) were measured. The current findings indicated some support for the benefits of (1) dissociative imagery for reducing perception of exertion and facilitating distraction from task, (2) associative imagery for extending task-adherence, and (3) imagery at large for increasing motivation and perseverance on task. This is important given that imagery's effects on exercise behavior is less known then its effects on elite sport performance, and researchers have long called for additional inquiry of these effects (see Duncan, Rodgers, Hall, & Wilson, 2011; Hall, 1995; Munroe-Chandler & Gammage, 2005). Imagery, through its motivational qualities (Paivio, 1985) potentiates the effects of attentional strategies, thus provides the exerciser with an additional tool to facilitate the physical activity experience. To help individuals adopt and maintain physical activity behavior, imagery and/or imagery-based interventions (e.g. simulated technologies) need to be made available. Suggestions for designing and integrating imagery into the physical activity regimens are discussed.