## 1 Introduction  
During performance, ballet dancers have a great need for stability and balance control [1; 2], along with a high level of general \"flexibility\", which are peculiar characteristics that improve with ballet training [1; 3; 4; 5]. Ankle control is of the utmost importance for executing static and dynamic positions typical of ballet dancing [6; 7]. In 2017, [PERSON] et al. reported the epidemiology of dance-related injuries between 2000 and 2013, defining ankle sprains as the most common injury [8]. Later, [PERSON] et al. and [PERSON] et al. collected data about their incidence and prevalence [9; 10]. Ankle sprains could cause chronic functional ability changes, as is common in groups of dancers and non-dancersalike [11; 12], also increasing the risk of re-injury [13]. In addition, it was seen that people with functional ankle instability had a less refined kinesthesia, in particular for inversion movements [14]. However, a prospective study conducted in 1996 by [PERSON] et al., based on stabilometry, demonstrated only short-term consequences after ankle sprain in ballet dancers [15]. Data about chronic ankle instability (CAI) in the general sporting population are, to date, not satisfactory to determine the presence of common aspects of CAI within individual sports [16]. However, an exploratory study conducted by [PERSON] et al. revealed a condition of CAI in 75.9% of university dance majors [17]. Despite new wearable technologies, such as Inertial Measurament Unit IMU [18; 19] and wireless electromyography (EMG) [20], having been proposed to investigate balance and postural control, stabilometry remains the most commonly used tool [21]. To date, there is a lack of studies about the chronic effects of an ankle injury in ballet dancers using stabilometry evaluation, but there is an increasing body of literature concerning this method [22; 23], including not previously injured ballet dancers [24]. A study performed by [PERSON] et al., using stabilometry to assess dancers with ankle injuries, found that non-acute ankle injuries could worsen postural stability of professional ballet-dancers during ballet-specific postures. However, they did not focus on a specific injury nor on a precise time-frame for the post-injury evaluation [25]. Another relevant aspect in the evaluation of balance control is represented by the visual system's role in proprioception, which has the potential to mask proprioceptive issues in athletes [26]. For this reason, it can be argued that in order to obtain reliable proprioceptive measures, visual occlusion is mandatory [27; 28]. As ankle control is crucial for successfully executing ballet specific positions and it could be impaired in ankle sprains, a position specific testing with closed eyes is needed. Moreover, some studies showed that athletic and sport training is task specific and skills acquired in a specific task did not completely translate to the same skills in different tasks [29; 30; 31]. Recently, [PERSON] et al. discovered that there were many sport skill-specific bias about sensory inputs for spatial orientation and postural control between experienced soccer athletes, ballet dancers, and nonathletes [32]. Considering the high incidence and prevalence of ankle injuries in professional and non-professional ballet dancers (from 3% to 25.6% of all musculoskeletal ballet injuries [4; 8; 10; 33]), and the primary role of ankle control to perform ballet-specific tasks, the aim of our study was to understand if non-professional ballet dancers, previously injured with a grade II ankle sprain, compared to dancers who did not suffer any ankle injury, carry a long-term stability deficit in ballet specific positions (passe, arabesque), thereby affecting ballet performance.