The Placebo Effect on Exercise Performance

ArticleinJournal of Cardiopulmonary Rehabilitation 36(Supplement) · May 2004with 541 Reads
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  • Article
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    The paper examines the placebo effect in sports performance. The possibility that the placebo effect is a more common phenomenon than the quantity of published research would suggest is briefly addressed. It is suggested that the placebo control design often used in sports performance research masks any placebo effects and thus presents a false picture of the mechanisms underlying performance-enhancing interventions in the real world. An electronic survey was sent to 48 competitive, international and professional athletes. Questions related to the placebo effect in competitive sport. Thirty responses were received. Data indicate that the majority (97%) of respondents believe that the placebo effect can exert an influence on sports performance, and that a significant number (73%) have experienced what they defined as a placebo effect. Inductive content analysis reveals that these experiences fall into several categories such as explicit placebo effects, inadvertent false beliefs, ritual and reverse placebo effects. Furthermore, 10 respondents (33%) offer explanations as to the nature of the placebo effect. Again, inductive content analysis reveals that these explanations fall into several categories including deliberate changes in competitive strategy, belief/expectancy, faith in a third party, and marketing. Overall, responses support previous experimental research and anecdotal reports that have found a relationship between belief and sports performance. It is suggested that further research be structured to not simply control for the placebo effect, but to elucidate it. Key pointsA survey of 30 athletes revealed that 73% have experienced a placebo effect in sport.Athletes suggest several potential explanations for these effects.Findings support the idea that placebo effects might be common in sport.Researchers and practitioners should be aware of the possible impact of these effects on research findings and competitive performance.
  • Article
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    The placebo effect, with its central role in clinical trials, is acknowledged as a factor in sports medicine, although until recently little has been known about the likely magnitude and extent of the effect in any specific research setting. Even less is known about the prevalence of the effect in competitive sport. The present paper reviews 12 intervention studies in sports performance. All examine placebo effects associated with the administration of an inert substance believed by subjects to be an ergogenic aid. Placebo effects of varying magnitudes are reported in studies addressing sports from weightlifting to endurance cycling. Findings suggest that psychological variables such as motivation, expectancy and conditioning, and the interaction of these variables with physiological variables, might be significant factors in driving both positive and negative outcomes. Programmatic research involving the triangulation of data, and investigation of contextual and personality factors in the mediation of placebo responses may help to advance knowledge in this area.
  • Article
    Full-text available
    The placebo effect, with its central role in clinical trials, is acknowledged as a factor in sports medicine, although until recently little has been known about the likely magnitude and extent of the effect in any specific research setting. Even less is known about the prevalence of the effect in competitive sport. The present paper reviews 12 intervention studies in sports performance. All examine placebo effects associated with the administration of an inert substance believed by subjects to be an ergogenic aid. Placebo effects of varying magnitudes are reported in studies addressing sports from weightlifting to endurance cycling. Findings suggest that psychological variables such as motivation, expectancy and conditioning, and the interaction of these variables with physiological variables, might be significant factors in driving both positive and negative outcomes. Programmatic research involving the triangulation of data, and investigation of contextual and personality factors in the mediation of placebo responses may help to advance knowledge in this area.
  • Article
    Full-text available
    The placebo effect, with its central role in clinical trials, is acknowledged as a factor in sports medicine, although until recently little has been known about the likely magnitude and extent of the effect in any specific research setting. Even less is known about the prevalence of the effect in competitive sport. The present paper reviews 12 intervention studies in sports performance. All examine placebo effects associated with the administration of an inert substance believed by subjects to be an ergogenic aid. Placebo effects of varying magnitudes are reported in studies addressing sports from weightlifting to endurance cycling. Findings suggest that psychological variables such as motivation, expectancy and conditioning, and the interaction of these variables with physiological variables, might be significant factors in driving both positive and negative outcomes. Programmatic research involving the triangulation of data, and investigation of contextual and personality factors in the mediation of placebo responses may help to advance knowledge in this area.
  • Chapter
    There is strong behavioral evidence that placebo and nocebo effects can influence aspects of motor performance like speed, force, and resistance to fatigue in athletes and non-athletes alike. These behavioral studies were essential for extending experimental investigation of the placebo and nocebo effects from the pain to the motor domain and to reveal how verbal suggestions and experiential learning are involved in shaping modulatory systems and related behavioral responses. However, the neural underpinnings of these effects in the motor domain are still largely unknown. Studies in healthy subjects demonstrated that the placebo-induced enhancement of force is associated with increased activity in the corticospinal system and that the placebo-induced reduction of fatigue can be disclosed by recording the readiness potential, an electrophysiological sign of movement preparation. Further evidence derives from studies in patients with Parkinson's disease that have directly demonstrated that placebo-induced improvements in motor symptoms are related to changes in subcortical neural firing activity and dopamine release. Future investigations are needed to better clarify the complex neural architecture underpinning the placebo and nocebo effects in the motor domain.
  • Article
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    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.
  • Article
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    Among the cognitive strategies that can facilitate motor performance in sport and physical practice, a prominent role is played by the direction of the focus of attention and the placebo effect. Consistent evidence converges in indicating that these two cognitive functions can influence the motor outcome, although no study up-to-now tried to study them together in the motor domain. In this explorative study, we combine for the first time these approaches, by applying a placebo procedure to increase force and by manipulating the focus of attention with explicit verbal instructions. Sixty healthy volunteers were asked to perform abduction movements with the index finger as strongly as possible against a piston and attention could be directed either toward the movements of the finger (internal focus, IF) or toward the movements of the piston (external focus, EF). Participants were randomized in 4 groups: two groups underwent a placebo procedure (Placebo-IF and Placebo-EF), in which an inert treatment was applied on the finger with verbal information on its positive effects on force; two groups underwent a control procedure (Control-IF and Control-EF), in which the same treatment was applied with overt information about its inefficacy. The placebo groups were conditioned about the effects of the treatment with a surreptitious amplification of a visual feedback signalling the level of force. During the whole procedure, we recorded actual force, subjective variables and electromyography from the hand muscles. The Placebo-IF group had higher force levels after the procedure than before, whereas the Placebo-EF group had a decrease of force. Electromyography showed that the Placebo-IF group increased the muscle units recruitment without changing the firing rate. These findings show for the first time that the placebo effect in motor performance can be influenced by the subject’s attentional focus, being enhanced with the internal focus of attention.
  • Article
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    The first part of the paper sums up contemporary approaches to the subject of placebo action. The definition of placebo is discussed, as well as the types of its effects and underlying mechanisms. Placebo is defined as a method or an element of the method without any specific activity for the condition being treated. A proposal is discussed to classify the effects of placebo in one coherent system consisted of eight different effects. Also the psychological mechanisms underlying placebo effect are discussed. These include classical conditioning, expectancy and anxiety, and relationships between them. In the second part of the paper,a summary is used for critical analysis of the data from the research on the applications of placebo as an ergogenic aid in sports. Discussion of the research results is focused on the effectiveness of placebo in athletic performance improvement, the influence of the information given to sportsmen on placebo action on its effectiveness, the influence of the information given to sportsmen on active methods action on their effectiveness, and prior experience with active methods as a factor contributing to a placebo effect. The discussed results prove the usefulness of placebo in athletic performance improvement, and this, indicate an important role of the information given to sportsmen in evoking a placebo effect and as a placebo factor modifying action of active procedures. The results of the discussed research suggest that the effects of any ergogenic aid are due to both its active components and psychological factors, e.i., placebo component of any active method.
  • Article
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    The empirical foundation of the 'placebo effect' is presented briefly, which is followed by the meta-analysis of the relatively few published reports that have investigated placebo effects in sports performance. Based on the analysis of the fourteen studies included in the meta-analysis, an overall medium effect size (0.4, 95% CI ranged from 0.24 to 0.56) was found. Homogeneity of effect sizes (χ 2 (13, N = 196) = 9.35, p = 0.75) and the feasibility of possible explanation models were also tested. In various sports (e.g. cycling, running, weightlifting) the investigation of the placebo effect on various physiological or performance measures (e.g. muscle power, heart rate, running speed) and psychological attributes (e.g. perceived exertion, post-experiment interviews) yielded significant results. Indeed, the common finding of the reviewed studies was that from the point of view of the athletes there is substantial performance enhancement as a result of different forms of placebos. However, the interpretation of some of the results may be limited by methodological shortcomings. Based on the reviewed articles and further questions emerging from them, methodological recommendations as well as possible research ideas are suggested for further inquiries in the area. Placebo-Effekt im Bereich Sport: Metaanalyse: Die Grundlagen der Erforschung des Place-bo-Effekts werden kurz geschildert, sodann werden die Ergebnisse unserer Metaanalyse vorge-stellt, die auf Grundlage einiger Studien zur Untersuchung des messbaren Placebo-Effekts bei Sportleistungen durchgeführt wurde. Auf Grundlage der in die Metaanalyse integrierten 14 Stu-dien wurde eine mittlere Wirkungsgröße festgestellt (0,4, mit 95% CI 0,24–0,56). Es wurden die Homogenität der Wirkungsgrößen (χ 2 (13, N = 196) = 9,35, p = 0,75), sowie die Möglichkeit der *
  • Article
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    BEEDIE, C. J., E. M. STUART, D. A. COLEMAN, and A. J. FOAD. Placebo Effects of Caffeine on Cycling Performance. Med. Sci. Sports Exerc., Vol. 38, No. 12, pp. 2159–2164, 2006. Purpose: The placebo effectVa change attributable only to an individual`s belief in the efficacy of a treatmentVmight provide a worthwhile improvement in physical performance. Although sports scientists account for placebo effects by blinding subjects to treatments, little research has sought to quantify and explain the effect itself. The present study explored the placebo effect in laboratory cycling performance using quantitative and qualitative methods. Method: Six well-trained male cyclists undertook two baseline and three experimental 10-km time trials. Subjects were informed that in the experimental trials they would each receive a placebo, 4.5 mgIkgj1 caffeine, and 9.0 mgIkgj1 caffeine, randomly assigned. However, placebos were administered in all experimental conditions. Semistructured interviews were also conducted to explore subjects` experience of the effects of the capsules before and after revealing the deception. Results: A likely trivial increase in mean power of 1.0% over baseline was associated with experimental trials (95% confidence limits, j1.4 to 3.6%), rising to a likely beneficial 2.2% increase in power associated with experimental trials in which subjects believed they had ingested caffeine (j0.8 to 5.4%). A dose– response relationship was evident in experimental trials, with subjects producing 1.4% less power than at baseline when they believed they had ingested a placebo (j4.6 to 1.9%), 1.3% more power than at baseline when they believed they had ingested 4.5 mgIkgj1 caffeine (j1.4 to 4.1%), and 3.1% more power than at baseline when they believed they had ingested 9.0 mgIkgj1 caffeine (j0.4 to 6.7%). All subjects reported caffeine-related symptoms. Conclusions: Quantitative and qualitative data suggest that placebo effects are associated with the administration of caffeine and that these effects may directly or indirectly enhance performance in well-trained cyclists. Key Words: EXPERIMENTAL DESIGNS, DECEPTIVE ADMINISTRATION, ERGOGENIC AIDS, BELIEF EFFECTS
  • Article
    To characterize differences in the perception and understanding of the placebo effect between sports physicians, coaches, athletes, and sports science personnel. A short 11-item questionnaire was administered addressing demographic details, understanding of the placebo effect, and willingness to use the effect in an elite sport setting. All participants were involved in national level sporting programs. A total of 187 individuals (17 sports physicians, 44 sports scientists, 30 national-level coaches, and 96 national-level athletes) completed the questionnaire. All participants were contacted and invited to participate voluntarily. INTERVENTIONS/ASSESSMENT OF RISK FACTORS: Not applicable. Self-reported responses on understanding and use of placebo effect in sport. A total of 94% of physicians and 98% of scientists, but only 44% of athletes, indicated a good understanding of the placebo effect. A majority of scientists (63%) and physicians (59%) administered placebo at least once a year. Most of scientists (95%) and a majority of physicians (71%) either mildly or strongly encouraged use of the placebo in their clinical practice. About 60% of athletes indicated they would not care if they were unknowingly administered a placebo: however, 30% of them would not appreciate being misled. There is a substantial difference in the level of understanding of the placebo effect between physicians and athletes in elite sport. Although athletes are willing to use the placebo effect, physicians need to be mindful of the manner of its implementation.
  • Article
    Full-text available
    The placebo effect-a change attributable only to an individual's belief in the efficacy of a treatment-might provide a worthwhile improvement in physical performance. Although sports scientists account for placebo effects by blinding subjects to treatments, little research has sought to quantify and explain the effect itself. The present study explored the placebo effect in laboratory cycling performance using quantitative and qualitative methods. Six well-trained male cyclists undertook two baseline and three experimental 10-km time trials. Subjects were informed that in the experimental trials they would each receive a placebo, 4.5 mg.kg caffeine, and 9.0 mg.kg caffeine, randomly assigned. However, placebos were administered in all experimental conditions. Semistructured interviews were also conducted to explore subjects' experience of the effects of the capsules before and after revealing the deception. A likely trivial increase in mean power of 1.0% over baseline was associated with experimental trials (95% confidence limits, -1.4 to 3.6%), rising to a likely beneficial 2.2% increase in power associated with experimental trials in which subjects believed they had ingested caffeine (-0.8 to 5.4%). A dose-response relationship was evident in experimental trials, with subjects producing 1.4% less power than at baseline when they believed they had ingested a placebo (-4.6 to 1.9%), 1.3% more power than at baseline when they believed they had ingested 4.5 mg.kg caffeine (-1.4 to 4.1%), and 3.1% more power than at baseline when they believed they had ingested 9.0 mg.kg caffeine (-0.4 to 6.7%). All subjects reported caffeine-related symptoms. Quantitative and qualitative data suggest that placebo effects are associated with the administration of caffeine and that these effects may directly or indirectly enhance performance in well-trained cyclists.
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