###### Abstract  
Mixed reality presents itself as a potential technological tool for the management of people with musculoskeletal disorders, without having as many adverse side effects as immersive virtual reality. The objective of this study was to explore the possibilities of a mixed-reality game, performing task-oriented cervical exercises compared to conventional therapeutic exercises in sensorimotor outcome measures in asymptomatic subjects. A randomized crossover pilot study was performed with two intervention groups: a mixed-reality group (MRG) and a conventional exercise group (CEG). The cervical joint position error test (CJPET) and deep cervical flexor endurance test (DCFET) were measured as sensorimotor outcomes. Statistically significant differences were found in the pre-post comparison in the DCFET for both groups (MRG: t = -3.87, \(p\) < 0.01; CEG: t = -4.01, \(p\) < 0.01) and in the extension of the CPET for the MRG (t = 3.50, \(p\) < 0.01). The rest of the measurements showed no significant differences comparing both groups pre- and postintervention (\(p\) > 0.05). Mixed reality has apparently the same positive effects as conventional exercises in sensorimotor outcomes in asymptomatic subjects. These results could help in future studies with mixed virtual reality in the management of people with musculoskeletal disorders. virtual reality; mixed reality; cervical spine; HoloLens +
Footnote †: journal: _Sciences_  
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The most used technologies in rehabilitation are virtual reality (VR), augmented reality (AR), and mixed-reality (MR) devices [3]. The \"boom\" in these devices in recent years is due to the increase in VR games and head-coupled immersive virtual reality devices since 2006. However, international experts agree on the differences between VR, on the one hand, and AR-MR, on the other hand [4]. VR does not interact with the real environment, and the user's interactions are always with a virtual environment [3; 4; 5]. AR and MR allow the user to see real objects and the environment in which they are placed, adding virtual and responsive objects on top of it. Some experts believe that the addition of MR on AR, among other things, gives virtual objects perspective and depth [3; 4; 5]. Nevertheless, public accessibility to MR is limited because of the high prices of the devices, among other limitations [3]. An example of MR, according to some experts, is the \"Microsoft(r) HoloLens\" headset device [4]. The side effects of VR, specifically immersive VR, were described many years ago [6]. Currently, despite advances in technology and new virtual reality devices, these adverse effects have not changed [7]: dizziness, headache, and motion sickness, among others. However, MR does not have these disadvantages, because the subject is always aware of their surrounding environment and reality. This opens up possibilities for its use in the management of musculoskeletal disorders in rehabilitation. In rehabilitation research, the use of VR applications in combination with other therapies has increased and offers the possibility of obtaining more precise and repeatable control of each session in comparison with conventional treatments. Moreover, it allows for the adaptation of interfaces to the user's limitations and for recreating safe virtual environments to improve and practice skills that have potential risk in the real world [8; 9]. Likewise, it enables the development of tele-rehabilitation platforms in which clinicians can remotely follow the evolution of patients from the data recorded during each session, goal-oriented challenges, and daily tasks [8; 9]. The latter being a key point of development in physical rehabilitation after the COVID-19 pandemic [10; 11]. In addition, for users, this can increase motivation by adapting exercises to the user's daily life.