Canterbury Christ Church University , Canterbury, UK.
J Sports Sci Med. 2008 Mar 1;7(1):166-75. eCollection 2008.
The placebo effect, a positive outcome resulting from the belief that a beneficial treatment has been received, is widely acknowledged but little understood. It has been suggested that placebo responsiveness, the degree to which an individual will respond to a placebo, might vary in the population. The study aimed to identify placebo-responsive participants from a previously published paper that examined the effects of caffeine and placebos on cycling performance. A quantitative model of placebo responsiveness was defined. 14 male participants were subsequently classified as either placebo responsive or non-responsive. Interviews were conducted to corroborate these classifications. Secondary quantitative analyses of performance data were conducted to identify further placebo responses. Finally, the five factor model of personality was used to explore relationships between personality and placebo responsiveness. Overall, 5 of 14 participants were classified as placebo responsive. Performance data suggested that 2 participants were placebo responsive whilst 12 were not. Interview data corroborated experimental data for these participants and for 9 of the remainder, however it suggested that the remaining 3 had experienced placebo effects. Secondary quantitative analysis revealed that performance for these 3 participants, whilst no better than for non-responsive participants, was associated with substantially increased oxygen uptake in the 2 conditions in which participants believed caffeine had been administered (7.0% ± 15.1; 95% confidence intervals -2.6 to 16.7, and 6.0% ± 15.4; -3.9 to 15.9 respectively). Finally, data suggested that the personality factors of extroversion, agreeableness, openness and neuroticism may relate to placebo responding. Placebo effects such as pain tolerance and fatigue resistance might be experienced by a percentage of participants but might not always be manifest in objective measures of performance. Key pointsBeliefs can have both positive (placebo) and negative (nocebo) effectsPlacebo effects may be experienced both objectively and subjectivelyCertain personality traits may be related to placebo respondingA multi-method approach may best elucidate placebo effects in sport.
安慰剂效应是指一种积极的结果，源于人们相信接受了有益的治疗。这种效应已被广泛认可，但了解甚少。有人认为，个体对安慰剂的反应程度（即安慰剂反应性）可能存在个体差异。本研究旨在从先前发表的一篇研究咖啡因和安慰剂对自行车运动表现影响的论文中，确定安慰剂反应性参与者。定义了一种安慰剂反应性的定量模型。随后，从 14 名男性参与者中分类为安慰剂反应性或非反应性。进行了访谈以证实这些分类。对绩效数据进行了二次定量分析，以确定进一步的安慰剂反应。最后，使用五因素人格模型探索人格与安慰剂反应性之间的关系。总体而言，14 名参与者中有 5 名被归类为安慰剂反应性。绩效数据表明，有 2 名参与者是安慰剂反应性，而 12 名参与者不是。访谈数据证实了这些参与者和其余 9 名参与者的实验数据，但表明其余 3 名参与者经历了安慰剂效应。二次定量分析显示，这 3 名参与者的表现虽然不比非反应性参与者好，但在他们认为已给予咖啡因的两种情况下，与氧摄取量的显著增加相关（7.0%±15.1；95%置信区间 -2.6 至 16.7，6.0%±15.4；-3.9 至 15.9）。最后，数据表明，外向、随和、开放和神经质等人格因素可能与安慰剂反应有关。一些参与者可能会经历诸如疼痛耐受和疲劳抵抗等安慰剂效应，但这些效应并不总是在客观的运动表现测量中表现出来。要点：信念既可以产生积极的（安慰剂）效应，也可以产生消极的（反安慰剂）效应。安慰剂效应可能在客观和主观上都有体验。某些人格特质可能与安慰剂反应有关。采用多方法的方法可能最能阐明运动中的安慰剂效应。
