All in the mind?: Pain, placebo effect, and ergogenic effect of caffeine in sports performance

The ergogenic effects of caffeine on performance are well documented. These effects are more evident in endurance and short-duration, sustained-effort events than in interactive or stop-go sports. Experimentally-induced placebo effects of caffeine on sports performance have also been observed in a number of recent studies. In the present paper it is argued that, given the nature of the sports in which caffeine effects are observed, the well documented hypoalgesic effects of caffeine, and the fact that pain is highly placebo-responsive, a reduction in perceived pain might be the common factor in both the biologic and placebo ergogenic effects of caffeine on sports performance. This idea is supported by evidence from medicine that suggests placebo effects are often associated with mechanisms similar or identical to those of the substance the subject believes they have ingested. Research findings from both biomedicine and sports medicine that attest to the interaction of biologic and psychologic factors in caffeine and pain responses are briefly reviewed. In conclusion, it is recommended that researchers investigate the pain hypothesis. Furthermore, researchers should consider psychosocial factors that might modulate the pain response as variables of interest in future caffeine and performance research

Athletes intending to use sports supplements are more likely to respond to a placebo

Purpose: We investigated associations between athletes’ use of sport supplements and their responsiveness to placebo and nocebo interventions. Methods: Participants (n=627) reported their intention to use, and actual use of, sport supplements. They then completed a 5x20m repeat sprint protocol in the baseline condition, prior to being randomized to one of three treatments. Participants in the positive-belief treatment were administered an inert capsule described as a potent supplement which would improve sprint performance. Participants in the negative-belief treatment were administered an inert capsule described as a potent supplement which would negatively affect sprint performance. Participants in the control treatment received neither instruction nor capsule. 20 minutes following baseline trials, all participants completed the same repeat sprint protocol in the experimental condition. Results: Compared to controls, no mean differences in performance were observed between baseline and experimental conditions for the positive-belief treatment (-0.07 ± 0.27%, d=0.02), but mean differences were observed for the negative-belief treatment (-0.92 ± 0.31%, d=0.32), suggesting a moderate nocebo effect. In the positive-belief treatment however, a relationship between intention to use supplements and performance was observed. Performance worsened by -1.10% ± 0.30% compared to baseline for participants not intending to use supplements, worsened by -0.64 ± 0.43% among those undecided about supplement use, but improved by 0.19 ± 0.24% among those participants intending to use supplements. Conclusion: Information about a harmful supplement worsened repeat sprint performance (a mean nocebo effect), whereas information about a beneficial supplement did not improve performance (no mean placebo effect was observed). However, participants’ intention to use sport supplements influenced the direction and magnitude of subsequent placebo responses, with participants intending to use supplements more likely to respond to the positive intervention

Advancing the understanding of placebo effects in psychological outcomes of exercise: lessons learned and future directions

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 conceptualization 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 direction

Placebo effect of an inert gel on experimentally induced leg muscle pain

Purpose: This study examined the therapeutic effects of an inert placebo gel on experimentally induced muscle pain in a sports therapy setting. It aimed to investigate the degree to which conditioned analgesia, coupled with an expectation of intervention, was a factor in subsequent analgesia. Methods: Participants were sixteen male and eight female sports therapy students at a UK University. With institutional ethics board approval and following informed consent proce- dures, each was exposed to pain stimulus in the lower leg in five conditions, ie, conditioning, prebaseline, experimental (two placebo gel applications), and postbaseline. In conditioning trials, participants identified a level of pain stimulus equivalent to a perceived pain rating of 6/10. An inert placebo gel was then applied to the site with the explicit instruction that it was an analgesic. Participants were re-exposed to the pain stimulus, the level of which, without their knowledge, had been decreased, creating the impression of an analgesic effect resulting from the gel. In experimental conditions, the placebo gel was applied and the level of pain stimulus required to elicit a pain rating of 6/10 recorded. Results: Following application of the placebo gel, the level of pain stimulus required to elicit a pain rating of 6/10 increased by 8.2%. Application of the placebo gel significantly decreased participant’s perceptions of muscle pain (P = 0.001). Conclusion: Subjects’ experience and expectation of pain reduction may be major factors in the therapeutic process. These factors should be considered in the sports therapeutic environment

You don't need to administer a placebo to elicit a placebo effect: Social factors trigger neurobiological pathways to enhance 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

Shared mechanism of teratogenicity of anti-angiogenic drugs identified in the chicken embryo model

Acknowledgements The authors would like to thank Maria Kisakyamaria and Scott McMenemy for preliminary experimental data. This work was supported by a Wellcome Trust-NIH PhD Studentship awarded to SB, WDF and NV (Grant number 098252/Z/12/Z). This research was supported in part by the Intramural Research Program of the National Institutes of Health, National Cancer Institute. The content of this publication does not necessarily reflect the views or policies of the Department of Health and Human Services, nor does mention of trade names, commercial products, or organization imply endorsement by the U.S. Government.Peer reviewedPublisher PD

Considerations of control groups: Comparing active-control with no treatment for examining the effects of brief intervention

© 2021 The Authors. Published by MDPI. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.3390/sports9110156Background: 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.Published versio

Computerised speechreading training for deaf children: A randomised controlled trial

Purpose: We developed and evaluated in a randomised controlled triala computerised speechreading training programme to determine a) whether it is possible to train speechreading in deaf children and b) whether speechreading training results in improvements in phonological and reading skills.Previous studies indicate a relationship between speechreading and reading skill and further suggest this relationshipmay be mediated by improved phonological representations. This is important since many deaf children find learning to read to be very challenging. Method: Sixty-six deaf 5-7 year olds were randomised into speechreading and maths training arms. Each training programme was comprised of10 minutesessionsa day, 4 days a week for 12 weeks. Children were assessed on a battery of language and literacy measures before training, immediately after training, 3 months and 10 months after training. Results: We found no significant benefits for participants who completed the speechreading training, compared to those who completed the maths training, on the speechreading primary outcome measure. However, significantly greater gains were observed in the speechreading training group on one of the secondary measures of speechreading. There was also some evidence of beneficial effects of the speechreading training on phonological representations, however these effects were weaker. No benefits were seen toword reading. Conclusions: Speechreading skill is trainable in deaf children. However, to support early reading, training may need to be longer or embedded in a broader literacy programme. Nevertheless, a training tool that can improve speechreading is likely to be of great interest to professionals working with deaf children