Abstract This chapter provides an overview of research into the placebo effect in sports and exercise. In doing so, it treats placebo effect research in Sports and equivalent research in Exercise as two distinct areas, each characterized by differing underlying assumptions: the improved understanding of psychological factors leading to enhanced performance in sports and the improved understanding of psychological and affective responses to exercise. It summarizes recent advances in understanding and knowledge, drawing attention to potential applications such as the reduction of drug use by athletes in sports and the enhancement of mental health in exercisers. We provide updated definitions and models of the placebo effect derived from Sports and Exercise research and propose future directions to better understanding and apply the placebo effect in both domains.

Abstract This chapter provides an overview of research into the placebo effect in sports and exercise. In doing so, it treats placebo effect research in Sports and equivalent research in Exercise as two distinct areas, each characterized by differing underlying assumptions: the improved understanding of psychological factors leading to enhanced performance in sports and the improved understanding of psychological and affective responses to exercise. It summarizes recent advances in understanding and knowledge, drawing attention to potential applications such as the reduction of drug use by athletes in sports and the enhancement of mental health in exercisers. We provide updated definitions and models of the placebo effect derived from Sports and Exercise research and propose future directions to better understanding and apply the placebo effect in both domains.

Organisations are aware of the need to maintain the mental health of their employees. People’s capacity to recognise and manage their moods and emotions is critical to sustainable mental health, performance, and quality of life, while failure to do so can result in underperformance, disengagement, and in some cases, mental illness. Employees of organisations that provide an appropriate strategy and support are likely to experience sustained psychological and mental health benefits. In this paper, we synthesise previous research into a theoretical framework distinguishing mood from emotion via both top-down (cognitive) and bottom-up (biological) factors. We propose a 4R model to help individuals Recognise a mood as distinct from an emotion, or vice-versa, and respond in one of three ways; Restore, Resolve, or Regulate. The model posits mood as an interoceptive signal of internal biological homeostasis, and emotion as a signal of external, often social, events that disrupt homeostasis; mood and emotion serve as internal and external bio-affective feedback loops, respectively. We propose that mood is modified positively by the restoration of homeostasis, whereas emotion is modified positively by behavioural resolution of the emotion-eliciting event. The 4R model is low-cost, preventative, and can be applied peer-to-peer in organisations without expert supervision.

Background: A large-scale online study completed by this research team found that brief psychological interventions were associated with high-intensity pleasant emotions and predicted performance. The present study extends this work using data from participants (n = 3376) who completed all self-report data and engaged in a performance task but who did not engage with an intervention or control condition and therefore present as an opportunistic no-treatment group. Methods: 41,720 participants were selected from the process and outcome focus goals intervention groups, which were the successful interventions (n = 30,096), active-control (n = 3039), and no-treatment (n = 8585). Participants completed a competitive task four times: first as practice, second to establish a baseline, third following an opportunity to complete a brief psychological skills intervention, and lastly following an opportunity to repeat the intervention. Repeated measures MANOVA indicated that over four performance rounds, the intensity of positive emotions increased, performance improved, and the amount of effort participants exerted increased; however, these increases were significantly smaller in the no-treatment group. Conclusions: Findings suggest that not engaging in active training conditions had negative effects. We suggest that these findings have implications for the development and deployment of online interventions.

Andrea W.M. Evers a, b Luana Colloca c Charlotte Blease d Jens Gaab e Karin B. Jensen f Lauren Y. Atlas g Chris J. Beedie h Fabrizio Benedetti i Ulrike Bingel j Christian Büchel k Jet Bussemaker l Ben Colagiuri m Alia J. Crum n Damien G. Finniss o Andrew L. Geers p Jeremy Howick q Regine Klinger r Stefanie Helena Meeuwis a Karin Meissner s Vitaly Napadow t Keith J. Petrie u Winfried Rief v Ionica Smeets w Tor D. Wager x Vishvarani Wanigasekera y Lene Vase z John M. Kelley A Irving Kirsch A on behalf of the Consortium of Placebo Experts

The placebo effect has been studied in medicine, psychology and neuroscience for well over 50 years. Whilst it remains controversial in many respects, it is now widely accepted as a real neurobiolo...

Objectives: Cardiorespiratory fitness (CRF) is independently associated with health and academic attainment in childhood and adolescence. Yet overweight/obesity remain the focus in public health policy. Surveillance of BMI and CRF considering school deprivation levels is limited. Therefore, we examined this in English Primary Schools. Methods: Participants (n=409) were students (9-10 years), from 13 schools. BMI and CRF (20 m shuttle-run) were measured at three time-points across the academic year and a fourth after summer recess. Results: BMI z-scores significantly decreased (p = 0.015) from autumn (z = 0.336 [CI 0.212 to 0.460]) to spring (z = 0.252 [CI 0.132 to 0.371]), and then significantly increased (p = 0.010) to summer (z = 0.327 [CI 0.207 to 0.447]). CRF significantly increased (p < 0.001) from autumn (z = 0.091 [CI -0.014 to 0.196]) to spring (z = 0.492 [CI 0.367 to 0.616]), no change (p = 0.308) into summer (z = 0.411 [CI 0.294 to 0.528]), and a significant decrease (p < 0.001) into the following autumn term (z = 0.125 [CI 0.021 to 0.230]). BMI was unaffected by deprivation; however, pupils from the most deprived areas saw significantly greater reductions in CRF compared with pupils from affluent areas. Conclusion: Significant reductions in children’s CRF occurred over the summer recess and was greater among children from schools in the most deprived areas. This may help inform future research into interventions targeting physical activity of school children, particularly over the summer recess.

Introduction: Clinical and laboratory studies demonstrate that placebo and nocebo effects influence various symptoms and conditions after the administration of both inert and active treatments. Objective: There is an increasing need for up-to-date recommendations on how to inform patients about placebo and nocebo effects in clinical practice and train clinicians how to disclose this information. Methods: Based on previous clinical recommendations concerning placebo and nocebo effects, a 3-step, invitation-only Delphi study was conducted among an interdisciplinary group of internationally recognized experts. The study consisted of open- and closed-ended survey questions followed by a final expert meeting. The surveys were subdivided into 3 parts: (1) informing patients about placebo effects, (2) informing patients about nocebo effects, and (3) training clinicians how to communicate this information to the patients. Results: There was consensus that communicating general information about placebo and nocebo effects to patients (e.g., explaining their role in treatment) could be beneficial, but that such information needs to be adjusted to match the specific clinical context (e.g., condition and treatment). Experts also agreed that training clinicians to communicate about placebo and nocebo effects should be a regular and integrated part of medical education that makes use of multiple formats, including face-to-face and online modalities. Conclusions: The current 3-step Delphi study provides consensus-based recommendations and practical considerations for disclosures about placebo and nocebo effects in clinical practice. Future research is needed on how to optimally tailor information to specific clinical conditions and patients’ needs, and on developing standardized disclosure training modules for clinicians.

Most academics agree that emotions and moods are related but distinct phenomena. The present study assessed emotion-mood distinctions among a non-academic population and compared these views with distinctions proposed in the literature. Content analysis of responses from 106 participants identified 16 themes, with cause (65% of respondents), duration (40%), control (25%), experience (15%) and consequences (14%) the most frequently cited distinctions. Among 65 contributions to the academic literature, eight themes were proposed, with duration (62% of authors), intentionality (41%), cause (31%), consequences (31%) and function (18%) the most frequently cited. When the eight themes cited by both academics and non-academics were rank ordered, approximately 60% overlap in opinion was evident. A data-derived summary of emotionmood distinctions is provided. These data should prove useful to investigators interested in developing a clearer scientific distinction between emotion and mood than is currently available. Emotion-Mood Distinctions 3 The terms emotion and mood represent a conundrum for psychologists. Although the words are frequently used interchangeably, most academics agree that the constructs they represent are closely related but distinct phenomena. Distinctions between them are clouded, in part, because an emotion and a mood may feel very much the same from the perspective of an individual experiencing either. Further, as observed by Ekman (1994), language does not always represent psychological reality. Because we are able to say that emotion and mood are different does not mean that they are, and any difference may be purely semantic. Therefore, emotion and mood may be different words for the same construct or different words for different constructs. Either way, it is incumbent on psychologists to attempt to clarify the exact nature of emotion and mood, their relationship with one another, and their respective relationships with other psychological phenomena. The rationale for pursuing agreed distinctions between emotion and mood is compelling for at least two reasons. First, conceptual clarity is a bedrock of science and several theorists have noted the existing confusion in terminology (e.g., Alpert & Rosen, 1990; Batson, Shaw, & Oleson, 1992; Bless & Schwarz, 1999; Ekman & Davidson, 1994; Lormand, 1985; Ketai, 1975). Perhaps as a result of this confusion, it is apparent that much of the research in the area of emotion and mood has produced equivocal findings. For example, Parkinson, Totterdell, Briner and Reynolds (1996), described the research into mood and memory as “vast and inconclusive” (p. 97); a situation perhaps caused by varied conceptualization and measurement of the mood construct. In other words, some researchers may have been investigating the emotion-memory link and others the mood-memory link, erroneously assuming the two relationships to be the same. Second, a clear distinction between emotion and mood would also be valuable from a therapeutic perspective. If the emotion of anxiety is in some way distinct from an anxious mood, then the difference may manifest itself as distinct causes or consequences of the two states and therefore may be sensitive to different therapeutic interventions. For example, if, as has been argued, emotion biases behavior whereas mood biases cognition (Davidson, 1994), emotionEmotion-Mood Distinctions 4 regulation strategies might focus on changing behavioral responses to environmental stressors, such as withdrawing from stressful situations rather than dealing with them, while mood-regulation strategies might focus on cognitive processes, such as encouraging positive rather than negative self-talk. Similarly, if emotions have specific causes but moods do not, as proposed by Ekman (1999), an effective emotion-regulation strategy may be to identify and re-appraise the cause; while an effective mood regulation strategy may be to moderate the resultant feelings by, for example, listening to music or engaging in physical exercise (Thayer, 1996). It is apparent that the distinguishing characteristics of emotion and mood have already received much attention in the literature. Ekman and Davidson (1994) noted that “most researchers interested in affect insist on distinguishing between them” (p. 94), but emphasized that the criteria used to achieve this distinction vary considerably 1 . A broad range of distinctions is proposed, ranging from physiological and neurological through to behavioral and social criteria. Distinctions are often based on the researcher‟s particular area of interest: a psycho-physiologist such as Panksepp (1994) may choose to differentiate the two by comparing the respective neural or somatic correlates of each; whilst a psycho-linguist such as Wierzbicka (1992) may choose to emphasize semantic distinctions in everyday language. Certainly, it seems likely that emotion and mood are distinct along more than one criterion, and it is easy to see how a difference in their respective underlying physiological processes would lead to differences in phenomenal experience, in turn leading to differences in expression, behavior, and linguistic descriptions of the two states. A significant feature of emotion-mood distinctions in the literature is that none of them, despite their intuitive appeal and complexity, are supported by published data 2 . Even traditionally data-rich sub-disciplines, such as neurology and psychophysiology, appear to make relatively arbitrary distinctions. That is, although objective neurological indices are used to distinguish between two states labeled as emotion and mood, the labels themselves are operational definitions 1 Arguably to avoid addressing the distinction between emotion and mood, many psychologists refer instead to affect, a term that tends not to be used in everyday language to describe human experience and one that was not mentioned once by any of the 106 respondents in the present study. The Oxford English Dictionary (Sykes, 1982) recognizes it as a term used only in psychology, and Dennett (1991, p. 45) described it as “the awkward term [for emotion] favored by psychologists.” 2 Schimmack and Siemer (1998) have addressed the question empirically, although this paper is as yet unpublished. Emotion-Mood Distinctions 5 based on the opinion of the researchers as to what constitutes an emotion and a mood, as opposed to any “real” occurrence of either emotion and mood per se (see Searle, 1999 for a discussion of the language-reality debate). One potential yet unexplored avenue of empirical investigation into the emotion-mood distinction is to examine what have been termed folk psychology or common sense theories; that is, theories based on “the assumptions, hypotheses and beliefs of ordinary people about behavior and mental experience” (Colman, 2001, p.283). Many emotion researchers have emphasized the scientific value of such theories (e.g., Lazarus, 1999; Levenson, 1994). Lazarus, for example, stated that “If we believe that emotions result from the way people construe and evaluate events, the most useful theory [of emotion] will be based on those construals and evaluations...if formulated appropriately, folk theory can be evaluated by observation, which is the hallmark of science, just as readily as can any other theory” (p. 61). We propose that folk psychology theories relating to emotion and mood offer much potential to further the academic study of the two constructs. In fact, in view of the limited progress of traditional empirical approaches, such an approach is not only warranted but may be long overdue. There are at least two further reasons for adopting a folk psychology approach to the present research question. First, all humans not suffering from neurological impairment have access to, and some degree of ability to communicate to others, the subjective experience of emotions and moods. They may experience what they call emotions in some situations, and what they call moods in others, and therefore may be able to describe perceived differences between the two. Thus, when canvassing people for their opinions on emotion and mood, we are not asking for their opinion about an abstract psychological problem, such as the nature of consciousness, we are asking them about a subject of which they may have intimate knowledge. Second, most English-speaking people use the words emotion and mood in everyday language, where for example the phrases “he‟s a very moody person” and “he‟s a very emotional person” could have distinct meanings. For example, Damasio (1999) proposed that a moody person Emotion-Mood Distinctions 6 is one whose reactions to an event are likely to be more consistent with the (usually negative) nature of his or her mood than with the actual nature of the event. Such a person in a hostile mood, for example, is unlikely to be friendly even in response to a friendly greeting. Further, a moody person is often defined as being “sullen and gloomy” (Sykes, 1982) and is “usually prone to bad temper or depression” (Parkinson et al., 1996, p.3). An emotional person, on the other hand, is one who “often reacts in a manner consistent with the nature of the immediate event or situation, whether positive or negative” (Alston, 1967; Sykes, 1982) but in an intense even extreme way; someone who perhaps cries while watching a sad film, or who is easily and demonstrably angered by minor irritations. Moreover, someone who does not feel “in the mood” is generally disinclined to do something (Lormand, 1985; Ortony et al., 1987), possibly for reasons of which he or she is not fully aware, perhaps relating to general perceptions of available physiological resources, ability or urgency. In contrast, someone who is “too emotional” to do something, has some more pressing concern, perhaps relating to a significant event or situation in his or her life such as a family bereavement or illness. In the present study, we adopted

Purpose: To investigate the placebo effect of caffeine on pacing strategy and performance over 1000-m running time trials using a balanced placebo design. Methods: Eleven well-trained male middle-distance athletes performed seven 1000-m time trials (1 familiarization, 2 baseline, and 4 experimental). Experimental trials consisted of the administration of 4 randomized treatments: informed caffeine/received caffeine, informed caffeine/received placebo, informed placebo/received caffeine, and informed placebo/received placebo. Split times were recorded at 200. 400, 600, 800, and 1000 m, and peak heart rate and rating of perceived exertion were recorded at the completion of the trial. Results: Relative to baseline, participants ran faster during informed caffeine/received caffeine (d= 0.42) and informed caffeine/received placebo (d= 0.43). These changes were associated with an increased pace during the first half of the trial. No differences were shown in pacing or performance between baseline and the informed placebo/received caffeine (d= 0.21) and informed placebo/received placebo (d= 0.10). No differences were reported between treatments for peak heart rate (eta(2) = .084) and rating of perceived exertion (eta(2) = .009). Conclusions: The results indicate that the effect of believing to have ingested caffeine improved performance to the same magnitude as actually receiving caffeine. These improvements were associated with an increase in pace during the first half of the time trial.

Research over the past 15 years on the placebo effect has substantiated its contribution to the efficacy of established treatments for a range of clinical conditions and identified its underlying mechanisms. There is also evidence that placebo effects contribute to the performance benefits of many ergogenic aids, and that performance can worsen when dummy treatments are associated with expectations of a harmful outcome (i.e. nocebo effect). Unfortunately, the bulk of sport research involving placebos and nocebos continues to be hampered by outdated definitions and conceptualizations of placebo effects and their mechanisms. This has implications not only for research but also application, as nearly 50% of athletes report experiencing a beneficial placebo effect, and a similar proportion of coaches report providing placebos to their athletes. The objective of this paper is to attempt to stimulate research by presenting updated definitions of placebo and nocebo effects in the context of sport, describing their major mechanisms and, highlighting the importance of the psychosocial context on placebo effects in the sport setting.

The aim of this review was to determine the magnitude of the placebo and nocebo effect on sport performance. Articles published before March 2019 were located using Medline, Web of Science, PubMed, EBSCO, Science Direct, and Scopus. Studies that examined placebo and nocebo effects of an objective dependent variable on sports performance, which included a control or baseline condition, were included in the analysis. Studies were classified into two categories of ergogenic aids: (1) nutritional and (2) mechanical. Cohen's d effect sizes were calculated from 32 studies involving 1513 participants. Small to moderate placebo effects were found for both placebo (d = 0.36) and nocebo (d = 0.37) effects and when separated by nutritional (d = 0.35) and mechanical (d = 0.47) ergogenic aids. The pooled effect size revealed a small to moderate effect size across all studies (d = 0.38). Results suggest that placebo and nocebo effects can exert a small to moderate effect on sports performance.

The placebo effect is traditionally viewed as a positive outcome resulting from a person's belief that an inert substance is in fact an active drug. In this context, it is often viewed as an intrapsychic phenomenon. However, most placebo effects reported in scientific research result from social interactions. These might be explicit, such as the description and administration of a treatment by a practitioner, or less explicit, for example, the recipient's perceptions of the practitioner's credibility, expertise, or confidence. On this basis, placebo effects are arguably social in origin. Many phenomena in sport are likewise social in origin, from the facilitation effects of a home field crowd or a cohesive team, to anxiety induced by an expert opponent or perceived underperformance. Such social effects have been the subject of research not only in social psychology, but also in experimental physiology. Emergent research in cognitive and evolutionary anthropology suggests that these social effects can be examined as a form of placebo effect. This suggestion is not a speculative position predicated on social and placebo effects sharing similar environmental cues and outcomes, but one based on a growing database indicating that drug, placebo, and social effects operate via common neurobiological mechanisms. In this paper, we examine the theoretical and empirical overlap between placebo and social effects and describe emergent research reporting specific brain pathways activated by socio-environmental cues as well as by drugs and placebos. We do so from three perspectives: the competitor, the teammate, the researcher.

Despite the apparent strength of scientific evidence suggesting that psychological benefits result from both acute and chronic exercise, concerns remain regarding the extent to which these benefits are explained by placebo effects. Addressing these concerns is methodologically and at times conceptually challenging. However, developments in the conceptualisation and study of placebo effects from the fields of psychology, neuroscience, pharmacology, and human performance offer guidance for advancing the understanding of placebo effects in psychological responses to exercise. In clinical trials, expectations can be measured and experimentally manipulated to better understand the influence of placebo effects on treatment responses. Further, compelling evidence has shown that the contribution of placebo effects and their underlying neurobiological mechanisms to treatment effects can be measured without administering a traditional placebo (e.g. inert substance) by leveraging psychological factors such as expectations and conditioning. Hence, the purpose of this focused review is to integrate lessons such as these with the current body of literature on placebo effects in psychological responses to exercise and provide recommendations for future research directions.

The understanding of placebo and nocebo effects in psychological responses to exercise may be improved by measuring expectations. Despite availability of several validated expectation measures, we argue for using scales that take both positive and negative expectations for exercise-induced changes into account. A cross-sectional survey was used to collect information on positive and negative expectations pertaining to how exercise would affect 14 different outcomes related to psychological health (n?=?966). Outcomes for which a majority of the sample (>50%) reported positive expectations for exercise-induced changes included: psychological well-being (75.3%), depression (74.3%), relaxation (74.2%), sleep quality (73.3%), stress (72.2%), anxiety (69.8%), energy (67.1%), and attention (60.2%). Outcomes for which a majority of the sample (>50%) reported a negative expectation for exercise-induced changes were muscle pain (66.3%), fatigue (57.3%), and joint pain (50.7%). Across all 14 outcomes, the percentage of participants with negative expectations for exercise-induced changes ranged from 5.9 to 66.3%. Elucidating the potential presence of placebo and nocebo effects through measurement of expectations may improve the understanding of variability in the direction and magnitude of exercise-related effects on psychological health. Although there were only 3 outcomes for which the majority of participants reported negative expectations, we found that negative expectations were present to some degree for all 14 outcomes. Thus, for researchers who wish to characterize expectations in studies of psychological responses to exercise, we recommend using measures that give equal consideration to positive and negative expectations.

Placebo and nocebo effects are a factor in sports performance. However, the majority of published studies in sport science are descriptive and speculative regarding mechanisms. It is therefore not unreasonable for the sceptic to argue that placebo and nocebo effects in sport are illusory, and might be better explained by variations in phenomena such as motivation. It is likely that, in sport at least, placebo and nocebo effects will remain in this empirical grey area until researchers provide stronger mechanistic evidence. Recent research in neuroscience has identified a number of consistent, discrete and interacting neurobiological and physiological pathways associated with placebo and nocebo effects, with many studies reporting data of potential interest to sport scientists, for example relating to pain, fatigue and motor control. Findings suggest that placebos and nocebos result in activity of the opioid, endocannabinoid and dopamine neurotransmitter systems, brain regions including the motor cortex and striatum, and measureable effects on the autonomic nervous system. Many studies have demonstrated that placebo and nocebo effects associated with a treatment, for example an inert treatment presented as an analgesic or stimulant, exhibit mechanisms similar or identical to the verum or true treatment. Such findings suggest the possibility of a wide range of distinct placebo and nocebo mechanisms that might influence sports performance. In the present paper, we present some of the findings from neuroscience. Focussing on fatigue as an outcome and caffeine as vehicle, we propose three approaches that researchers in sport might incorporate in their studies in order to better elucidate mechanisms of placebo/nocebo effects on performance.

Abstract The aim of the study was to determine whether estimates of the speed–duration relationship are affected using different time-trial (TT) field-based testing protocols, where exhaustive times were located within the generally recommended durations of 2–15 min. Ten triathletes (mean ± SD age: 31.0 ± 5.7 years; height: 1.81 ± 0.05 m; body mass: 76.5 ± 6.8 kg) performed two randomly assigned field tests to determine critical speed (CS) and the total distance covered above CS (D́). CS and D́ were obtained using two different protocols comprising three TT that were interspersed by 60 min passive rest. The TTs were 12, 7, and 3 min in Protocol I and 10, 5, and 2 min in Protocol II. A linear relationship of speed vs. the inverse of time (s = D́ × 1/t + CS) was used to determine parameter estimates. Significant differences were found for CS (p = 0.026), but not for D́ (p = 0.123). The effect size for CS (d = 0.305) was considered small, while that for D́ was considered moderate (d = 0.742). CS was significantly correlated between protocols (r = 0.934; p < 0.001), however, no correlation was found for D́ (r = 0.053; p = 0.884). The 95% limits of agreement were ±0.28m s−1 and ±73.9 m for CS and D́, respectively. These findings demonstrate that the choice of exhaustive times within commonly accepted durations results in different estimates of CS and D́, and thus protocols cannot be used interchangeably. The use of a consistent protocol is therefore recommended, when investigating or monitoring the speed–duration relationship estimates in well-trained athletes.