HypnoStrength Data

Hypnosis can enhance athletic performance, such as improving soccer and basketball skills (Barker et al., 2010; Schreiber, 1991). In our study, we investigate whether hypnosis can also affect muscle strength. Prior research was done many years ago (mostly uncontrolled) and also showed heterogeneous results. This study aims to investigate hypnosis' impact on physiological parameters, update research, and clarify previous findings. We use handgrip strength (HGS), a parameter easy to measure and indicating not only the muscle strength, but also the medical condition (e.g. lung function - Chen at al., 2020). We developed a hypnosis intervention that makes participants feel strong. Specifically, they received suggestions to feel strong in their hand and arm. With a link to a trigger stimulus (post-hypnotic anchor, in this case a star-shaped hand), they were able to evoke the positive feelings after hypnosis. We measured HGS via hand dynamometer, and feeling of strength with a visual analogue scale (VAS) and questionnaires. We tested the effect of the post-hypnotic anchor on two experimental sessions, one in which the post-hypnotic anchor was installed (day 1) and one week later (day 8) (long-term). Analysis of the data revealed no statistically significant increases in objective strength between-groups for all measurement points. However, within-subject analyses showed a significant long-term increase in objective strength compared to baseline, evident one week post-intervention (day 8) but not immediately after the intervention on day 1. Feeling of strength did significantly increase between-groups immediately after the intervention (hypnosis / reading), but not long-term on day 8. Within-subjects, a significant increase was found for both measurement points- immediately after the intervention and also long-term on day 8. Our data indicate that hypnosis can influence HGS on both objective and subjective levels. Although our findings did not definitively demonstrate an increase in objective strength between-groups, they suggest a trend supported by significant within-subject improvements. Notably, subjective perceptions of strength yielded clearer outcomes, indicative of hypnosis' capacity to influence the perception of strength through suggestive interventions. Our intervention can help athletes to improve their sport performance and patients to regain their health after a medical intervention.