The anticipatory regulation of performance: the physiological basis for pacing strategies and the development of a perception-based model for exercise performance

Abstract

During self-paced exercise, the exercise work rate is regulated by the brain based on the integration of numerous signals from various physiological systems. It has been proposed that the brain regulates the degree of muscle activation and thus exercise intensity specifically to prevent harmful physiological disturbances. It is presently proposed how the rating of perceived exertion (RPE) is generated as a result of the numerous afferent signals during exercise and serves as a mediator of any subsequent alterations in skeletal muscle activation levels and exercise intensity. A conceptual model for how the RPE mediates feedforward, anticipatory regulation of exercise performance is proposed, and this model is applied to previously described research studies of exercise in various conditions, including heat, hypoxia and reduced energy substrate availability. Finally, the application of this model to recent novel studies that altered pacing strategies and performance is described utilising an RPE clamp design, central nervous system drugs and the provision of inaccurate duration or distance feedback to exercising athletes.We have previously described studies of pacing strategy using various experimental interventions, including faster and slower starts, higher temperatures, hypoxia, hyperoxia and altered energy substrate availability. 1 We have proposed the presence of a complex, regulatory system that mediates changes to skeletal muscle motor unit activation and work rate in order both to optimise performance and prevent potentially harmful changes to homeostasis. We subsequently develop a model to explain how this regulatory system might utilise the subjective rating of perceived exertion (RPE) as a means of integrating afferent information and a variety of other cues in order to achieve these objectives during exercise. THE RPE DURING CONSTANT WORKLOAD EXERCISE: THE LIMIT VARIABLE FOR VOLITIONAL PERFORMANCE TO FATIGUEOften measured as an index of subjective perception of effort during exercise, the RPE has been causally linked to physiological variables such as muscular force, 2 heart rate, ventilation, respiratory rate, oxygen uptake and blood lactate concentrations.3 Borg 4 has stated that the RPE is the ''single best indicator of physical strain'', and ''integrates various information, including the many signals elicited from the peripheral working muscles and joints, from the central cardiovascular and respiratory functions, and from the central nervous system''. The RPE also incorporates other mediators, most notably psychological and affective components.5 6 The overall sensation of exertion measured during exercise is thus the conscious/ verbal manifestation of the integration of these psychological and physiological cues (see Hampson et al 7 for a complete review). The biological link between the subjective sensation of effort and the physiological changes occurring during exercise is of crucial importance, because it provides a mechanism by which the RPE could, in theory, contribute to the regul...

Physiological and Psychological Effects of Deception on Pacing Strategy and Performance: A Review

“…This finding was supported by Billaut et al [45] who used a repeated sprint cycling protocol and also found no differences in RPE between trials where participants were not informed how many sprints they would be completing in comparison to an accurately informed trial. The finding of a lower accumulation of work over the ten, six second sprints in the unknown condition supports theory of selfpaced exercise [21] , where work-rate is expected to be set more conservatively. The inconsistency in the findings of RPE responses in open-loop exercise may be explained by differences in participant characteristics.…”

“…Baden et al's study [46] found that in a 20-minute treadmill exercise bout at a fixed intensity of 75% of peak speed, oxygen uptake was lower in the latter half of a trial in which the duration was unknown compared to a trial where the duration was known. Therefore a greater running economy and more efficient performance due to the uncertainty of the exercise provide support for Tucker's [21] model. However, the mechanisms by which efficiency was enhanced are currently unknown as no differences in RPE, heart rate or stride frequency were found between the unknown and known conditions.…”

“…Theoretically, the deception of external feedback prior to exercise would cause physiological resources to be incorrectly allocated and create a discrepancy between the perceived and actual demands of the exercise. If the deception creates a situation where the duration of exercise is shorter than expected, then the participant will most likely not produce their best performance due to planning and executing a more conservative pacing strategy intended for a longer duration [21] .…”

“…The inconsistency in the findings of RPE responses in open-loop exercise may be explained by differences in participant characteristics. As the endpoint is unknown, the RPE template will be set based on previous experience [21] , which varied between these studies [44][45][46] as trained and untrained participants were used.…”

“…Perception of effort, which is usually measured by a 10-or 16-point rating of perceived exertion (RPE) scale [18,19] , represents an overall conscious awareness of the internal physiological state, sensations generated during physical activity and the known endpoint [5,20] . One proposition is that perceived exertion plays an anticipatory role in exercise regulation, as determined by changing patterns of physiological afferent feedback [21] . The model states that a 'template RPE' is set prior to the commencement of exercise based upon the expected exercise duration and the previous experience of similar bouts of exercise, which are two cues of teleoanticipation that are regarded as the most influential to the pacing strategy.…”