## 1 Introduction  
Dance imagery influences the dancer's body and movement [1] as well as their technical skills [2]. These voluntary mental creations are used in training sessions and performances [3, 4].  
Mental imagery in dance is mostly presented as a teaching tool used to learn specific dance movements. Dance teachers mainly use metaphors to help students properly execute different choreographic elements. Dance students are encouraged to imagine a particular movement in order to perform it correctly and perfect their technique [5, 6]. Mental images are used in postures and movements of varying difficulty and are gradually incorporated in dance training. Primary dance students first learn how to use mental imagery in a static parallel position (i.e., standing straight with feet joined together). Next, they learn dynamic movements of medium difficulty like demi pointe releve in parallel position (i.e., from parallel position lifting the heels above the floor). Next, they move into more complex movements like demi plie in first classical ballet position (i.e., bending the hips and knees with heels joined together and feet in opposite direction).  
The goals of mental imagery include mastering technical skills, enhancing self-confidence, or taking inspiration for choreography [1]. According to [PERSON], mastering mental imagery is a long-lasting task and resembles learning a new language [7]. Regular exercises and patience are essential to achieve the intended goal [7]. The Franklin Method(r) is a system based on using mental imagery techniques for improvements in musculoskeletal system function [1,8]. According to [PERSON], his method is effective and evidence-based, recommended on every dance education stage. The Franklin Method(r) is focused on the body and its functions and improves the quality of movement [9]. However, according to [PERSON] and [PERSON] (2012), dancers, especially those younger and less experienced, are often not aware if the imagery is actually effective [8]. As a matter of fact, mental imagery is used by dancers of all ages and ability levels: from primary-aged children through amateurs to professional dancers. It turns out that the more experienced the dancer, the more complex images they use [1]. Professional, high-level dancers mostly employ mental techniques to improve their posture, visualize emotions, or increase jump height [4,10].  
According to [PERSON] et al. (2016), despite the variety of research focused on mental imagery methods, the conclusions are not consistent [1]. This indicates that the use of mental images in the field of dance or sport training or performance is still to be discovered and verified with objective measurement methods.  
Biomechanical tools such as electromyography, dynamometry, or motion capture systems provide an objective assessment of the training effectiveness or performance correctness [11, 12, 13]. However only a few studies have been found on using electromyography on dancers for verification of the mental imagery effectiveness using the Franklin Method(r) on jump height [14] or other mental techniques on demi plie performance [15].  
Therefore the aim of this study was to identify the influence of dance imagery based on the Franklin Method(r) on the electromyographic parameters of selected muscles in a professional ballet dancer during three ballet tasks of varying difficulty: parallel position, demi pointe releve, and demi plie.