Hypnosis is generally believed to have existed since ancient societies (Hammond, 2013). In China, the earliest recorded text on hypnosis was in the Huangdi Neijing [written during the Warring States period (475-221 BC) and the Han dynasty (206 BCE–220 CE)]. It mentioned a healing method called “Zhu You,” which appears to have many elements in common with hypnosis from a modern perspective (Yao, 2010). “Zhu You” was a sort of witchcraft. It used spells to cure diseases. Apart from China, the “Sleep Temples” in ancient Greek and Roma centuries were used to induce a sleep-like state (Muthu, 1930), which can be regarded as the earliest hypnosis-like state. Sleep temples could heal a variety of ailments. Many of them were psychological in nature. The treatment involved chanting, meditation, fasting, placing the patients into a trance-like or hypnotic state, and analyzing their dreams, etc.

Modern hypnosis could be traced back to Franz Mesmer’s (1734–1815) animal magnetism theory in the 1770s. He believed that all things in nature shared a common magnetic force, and disease could be cured through a magnetic field (Hammond, 2013). His mesmerism was regarded as mysterious witchcraft and was not adopted by the scientific community. The mesmerism in that era performed under the exaggerated background of various spells and astrological wall decorations, with mesmerists using various strange props to inspire the souls of sleepwalkers to come and communicate with them (Darnton, 1968). Later, James Braid (1795–1860) ended the old witchcraft era of hypnotism mystification. He believed that hypnosis was not produced from magnetism. It was a kind of sleep-like state and defined as “a peculiar condition of the nervous system, induced by a fixed and abstracted attention of the mental and visual eye, on one object, not of an exciting nature” (Braid, 1843). At the same time, he coined the term “hypnosis” (to sleep) from the ancient Greek term “Hypnos” (the god of sleep in ancient Greek mythology). He also emphasized a theoretical conception of hypnosis as a state of increased suggestibility and a form of sleep (Hammond, 2013). With the in-depth study of hypnosis by scientists, there were two opposing schools in hypnosis academia in the 19th century. They were the Paris School represented by Jean-Martin Charcot (1825–1893) and the Nancy School represented by Hippolyte Marie Bernheim (1840–1919) and Ambroise-Auguste Liébeault (1823–1904). The Nancy School advocated the “suggestion theory,” which believed that the role of suggestion was very important in the process of hypnosis. The phenomenon produced by hypnosis was a reaction caused by the hypnotized person accepting the hypnotist’s suggestion and that the person could be put into a hypnotic state by purely verbal suggestion (William and Edmonston, 1986). The Paris School believed that hypnosis was a form of hysteria, and those who could be hypnotized were psychotic (Sheehan and Perry, 1976). Although there were many different understandings of hypnosis between these two schools, they contributed to the development of hypnosis. Subsequently, scholars such as Sigmund Freud (1856–1939) and Ivan Petrovich Pavlov (1849–1936) were also involved in hypnosis research, making hypnosis a valuable applied science.

Hypnosis is a technique of communication using psychological suggestions. Under hypnosis, the hypnotized person is more open to suggestions. The result of hypnosis is that they gain greater control over their own minds and their own actions. In the process of hypnosis, the hypnotist will repeatedly use the auditory, visual and tactile stimuli to induce the hypnotized person into a trance state. In the meantime, the hypnotized person will also be asked to relax, imagine and concentrate on the hypnotist’s suggestions. After the hypnotized person enters the hypnotic state, the hypnotist will implement various treatments to address the patient’s psychological disorders. Nowadays, hypnosis has been used in numerous industries such as medical/psychotherapeutic uses, sports training, military uses, self-improvement, employee training, and police confession. Moreover, studies have shown that the hypnotic effect is closely related to the hypnotized person’s attitude and belief in the hypnotic process (Franquelo et al., 2020, 2021a,b). More and more evidence show that hypnosis is a scientific psychological therapy technique.

Psychological training for athletes is an essential part of sports training because, in any competitive event, there is always the possibility of misplaying and losing. Many of the best athletes have worked hard for decades to perform at the top-level competition but may not always win the championship. At the same time, athletes’ misplay is a sort of publicity trick and a conversation topic among the ground. Therefore, the more higher up into the top elite classes athletes are, the more they are under tremendous psychological pressure. A study from Australian academics mentioned that athletes’ emergence of mental illness is usually at the peak of their competitive careers (Allen and Hopkins, 2015). Moreover, they experience unique stresses, including sport-related stress (Noblet and Gifford, 2002), injuries (Smith, 1996; Appaneal et al., 2009), life away from home (Bruner et al., 2008), and burnout (Gustafsson et al., 2011). For these reasons, it is important to pay attention to athletes’ psychological problems. Hypnosis, used as an adjuvant technique, can help to prevent the mental illness of athletes, but also can improve their training results and competition performance. Sports psychologists may apply hypnosis to athletes’ psychological training because hypnosis may help athletes attain relaxation during practice and competition and help athletics control anxiety and manage stress (Paccagnella, 2004). Meanwhile, hypnosis is a simple and easy way to adjust the physical and mental conditioning without special requirements in terms of venues or equipment. A previous review indicated that hypnosis was effective for improving performance across multiple sports, with the strongest results found for basketball, golf, soccer and badminton (Milling and Randazzo, 2016). Therefore, hypnosis is widely used in sports and competitions.

At present, there are several defects in hypnosis application in sports. Firstly, in most studies, the sample size was small. Some had fewer than 10 subjects. Secondly, the design of the research scheme is not rigorous enough. For example, some studies were just pre - and post-comparison studies without different types of hypnosis for comparison. The evaluators of hypnosis effect were not blind to the research scheme. Results could easily be influenced by subjective factors when evaluated. Thirdly, no randomized placebo-controlled studies have been found. Fourth, there are very few studies on the effect of hypnosis on performance in competitions. In the future, studies on the application of hypnosis in sports can be appropriately conducted with large sample sizes, setting up different types of hypnosis for comparison, blinding the evaluators of effects of hypnosis, and setting up reasonable and scientific placebo control. In addition, the effect of hypnosis on performance in competitions should also be further studied.

There is a lot of evidence that hypnosis may be a helpful tool to address a variety of issues in sports; for example, hypnosis may help athletes improve their psychological quality, increase their self-confidence, relieve their fatigue, restore energy, help them better concentrate on the daily training and competition, and better improve their skills. However, there is little methodologically rigorous empirical research substantiating its value, and there is still a lack of extensive experimental evidence to prove its mechanism. As a result, hypnosis in sports still needs to be studied in more depth and breadth, and empirical verification is necessary and required. But it is undeniable that hypnosis is a simple and easy way to adjust physical and mental conditioning without special requirements in terms of venues or equipment.

ZL contributed to the literature search, interpretation, conceptualization, and drafted the manuscript. S-XL contributed to conceptualization, interpretation, and final approval of the manuscript. Both authors contributed to the article and approved the submitted version.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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