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10.09.2015


Belief factor crucial for effect of supplements

Sports supplements work better if you believe in them. Only when the power of the mind - or the placebo effect if you prefer - is combined with the physiological effects of a supplement do athletes actually achieve better results. Scottish sports scientists Mary McClung and Dave Collins discovered this in an unusual study, which they published in 2007 in the Journal of Sport & Exercise Psychology.

Study
The researchers did an experiment with 16 endurance athletes, all of whom trained at least 5 times a week, and on top of that did high-intensity training sessions at least twice a week. The researchers got the subjects to run 1000 metres on four occasions.

Belief factor crucial for effect of supplements

Belief factor crucial for effect of supplements
One time the subjects were given a placebo, and the researchers told them that this was what they were getting. [Told No Drug/Given No Drug]

Another time the subjects were given a placebo, but were told by the researchers that they were getting an effective performance enhancer. [Told Drug/ Given No Drug]

A third time the subjects were given a proven effective supplement, but were told by the researchers that they were getting a placebo. [Told No Drug/ Given Drug]

A fourth time the subjects were given a proven effective supplement and the researchers told them this too. [Told Drug/Given Drug]

The supplement used was sodium bicarbonate. The runners were given 0.3 g sodium bicarbonate [structural formula shown above] per kg bodyweight dissolved in 750 ml water about two hours before they had to run the 1000 metres. The placebos were bottles containing 750 ml water.

Results
The figure below shows that the subjects had the best times when they were given sodium bicarbonate and knew it too. The subjects' second best times were when they were given a placebo, but told that they'd been given an effective performance enhancer. When the subjects were given sodium bicarbonate, but thought that they'd been given a placebo, the substance didn't work.


Belief factor crucial for effect of supplements


Belief factor crucial for effect of supplements



The athletes reported less fatigue [RPE] when they thought they'd been given a placebo.

Conclusion
"The determining factor here was associated with the athlete's belief in what they are being told or given", the researchers concluded. "The RPE results clearly support this contention because only the information offered (Told) had any significant impact. In short, athletes were almost looking for effects as a result of the expectancy prime provided, and they apparently paid much more attention to this than the actual messages sent by their muscles."

"Could this be a learning point for coaches, psychologists, and other support staff regarding their relationships with athletes? The role that a coach may play in enhancing self-confidence in his or her athlete has been acknowledged in the literature, but mostly in relation to goal setting."

"Based on these results, we would highlight the need for coaches and support staff to complete a 'hard sell' of their training methods to their athletes, and to check frequently that the performers are completely confident in what they are being asked to do. In short, procedures will enjoy a valuable bonus if the consumers are initially convinced, and remain confident, of their efficacy."

Mistaken conclusion
Nitpickers will conclude from this study that sodium bicarbonate 'therefore' doesn't work. But there are many studies that have shown the efficacy of sodium bicarbonate. Unfortunately the effective dose gives your stomach a heavy hammering, and many athletes feel nauseous after taking the stuff. This side effect was probably the reason that sodium bicarbonate didn't work in the experiment described here when the athletes believed they had been given a placebo.

Source:
J Sport Exerc Psychol. 2007 Jun;29(3):382-94.

More:
Placebos work even if you know you're taking a placebo 05.09.2015