Re: Performance enhancing drugs or techniques may exist that can’t yet be detected, experts admit
The debate over whether or not acupuncture elicits any specific effects beyond placebo still appear to be unresolved (1). Interestingly, both acupuncture and placebo interventions may boost sports performance.
There are several scientific reports suggesting that stimulation of acupuncture points in trained athletes may substantially improve their performance in light athletics, swimming and cycling. In a series of experimental investigations in competitive athletes Birger Kaada from Norway reported that the runners and swimmers improved their personal results after stimulation of the acupuncture point LI4 (Hegu) (2). LI4 is one of the most commonly used acupuncture points in mainstream medicine (Figure 1) for treatment of acute and chronic pain, allergic rhinitis, etc. (3). In one of these crossover investigations, a 45 minute treatment involving electrical stimulation of LI4 led to a mean improvement of 2.3 seconds in 800m track racing and 4.3 seconds in 1000m road racing, whereas the placebo condition did not (2). The same effect was seen in swimmers (100m, 200m and 400m swimming), who improved their personal best times, usually taking years of training to achieve this improvement without LI4 stimulation (2).
Elite athletes from national teams of Asian countries prefer acupuncture to mainstream medicine in treatment of sports injuries, whereas more than 70% of cases are treated using acupuncture and related techniques (4,5). Looking at the medal statistics of last Olympics 2008 in Beijing (Table 1), where China was leading among the countries and Asia among the continents in total number of medals and especially in number of gold medals, one can hypothesise that along with injury treatment acupuncture may also be used to enhance or optimise the performance of the athletes.
Preliminary data suggests there may be specific effects of acupuncture point stimulation on some aspects of muscle recovery after physical work (6), but the non-specific effects may contribute substantially to the overall effect of acupuncture in sports.
It seems that competitive athletes may be extraordinary sensitive to placebo effects: a small survey among top professional athletes found that 97% of them believed that the placebo effect influenced the success of sports performance and noted that 73% reported experiencing a placebo effect during their career (7). A recent systematic review of 12 randomised trials, in which all studies used inert substances believed (by participants) to be ergogenic aid, revealed that placebo effects were seen to varying degrees in all sports studied, from weight-lifting to endurance cycling (8). In one of the investigations, sodium bicarbonate and placebo were given in a blinded crossover manner to athletes completing a series of 1000m time runs. Results showed that believing one had taken the substance resulted in times almost as fast as those associated with consuming the active substance itself. In contrast, taking the sodium bicarbonate without knowledge did not influence sports performance (9). Motivation, expectancy and conditioning, and their interaction, are suggested to be the mechanisms of these effects in athletes.
Conditioning athletes using pharmacological substances, e.g. opioids, could potentially be misused as a doping. It is well known that placebo-induced analgesia can be mediated through the release of endogenous opioids (10). Benedetti el al demonstrated that an intramuscular injection of saline can produce a measurable opioid-mediated increase in physical performance. This was performed in healthy volunteers who were conditioned with intramuscular morphine on two occasions immediately before pre-competition training sessions (11). The effect was blocked by the administration of the opioid-receptor antagonist naloxone. This opioid-like effect of placebo has raised the question of whether the application of placebo is ethically acceptable in sports competitions, formally throwing the shadow of suspicion on all forms of mental training, psychological interventions and acupuncture, all of which can potentially enhance sport performance.
According to existing World Anti-Doping Agency (WADA) criteria, both placebo and acupuncture have a potential to be included in the list of prohibited substances and methods (doping). Indeed, according to the World Anti-Doping Code 2009, a substance or method shall be considered for inclusion on the prohibited list if WADA determines that the substance or method meets any two of the following three criteria: (i) medical or other scientific evidence, pharmacological effect or experience that the substance or method, alone or in combination with other substances or methods, has the potential to enhance or enhances sport performance; (ii) medical or other scientific evidence, pharmacological effect or experience that the use of the substance or method represents an actual or potential health risk to the athlete; (iii) WADA's determination that the use of the substance or method violates the spirit of sport described in the Introduction to the Code (12).
Acupuncture may fulfil the first criterion, either through specific or non-specific (placebo) effects. Serious adverse events related to acupuncture needling are very rare, but we cannot deny the potential for health risks, despite there being no reports of adverse events in athletes.
However, even if acupuncture has the potential to enhance sport performance, we do not believe that the stimulation of acupuncture points can be considered to violate the spirit of sport.
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2. Kaada B. Improvement of physical performance by transcutaneous nerve stimulation in athletes. Acupunct Electrother Res 1984;9:165-80.
3. Chernyak GV, Sessler DI. Perioperative acupuncture and related techniques. Anesthesiology 2005;102:1031-49.
4. Lin ZP, Chen YH, Chia F, Wu HJ, Lan LW, Lin JG. Episodes of injuries and frequent usage of traditional Chinese medicine for Taiwanese elite wrestling athletes. Am J Chin Med 2011;39:233-41.
5. Watts J. Feature: olympian pins and needles. Lancet 2005; 366(supplement 1): S62–S63.
6. So RC, Ng JK, Ng GY. Effect of transcutaneous electrical acupoint stimulation on fatigue recovery of the quadriceps. Eur J Appl Physiol 2007;100:693-700.
7. Trojian TH, Beedie CJ. Placebo effect and athletes. Curr Sports Med Rep 2008;7:214-7.
8. Beedie CJ, Foad AJ. The placebo effect in sports performance: a brief review. Sports Med 2009;39:313-29.
9. McClung M, Collins D. "Because I know it will!": placebo effects of an ergogenic aid on athletic performance. J Sport Exerc Psychol 2007;29:382-94.
10. Wager TD, Scott DJ, Zubieta JK. Placebo effects on human μ-opioid activity during pain. PNAS 2007;104:11056-61.
11. Benedetti F, Pollo A, Colloca L. Opioid-mediated placebo responses boost pain endurance and physical performance: is it doping in sport competitions? J Neuroscience 2007;27:11934–9.
12. http://www.wada-ama.org/rtecontent/document/code_v2009_en.pdf (accessed 28. June 2012).
Competing interests: No competing interests