## 2 Related Work  
Several exergames have been proposed to target mobility limitations, cognitive impairment, or urinary incontinence (Table 1). In 2015, the iStopFalls consortium proposed the development of an innovative home-based solution for fall prevention, comprising exergames for balance and cognition provided by a Kinect-based solution [46]. In more recent studies, Kinect continues to be the first choice when it comes to tracking and evaluating full-body movements [31, 44, 47]. However, according to [52], more than one Kinect sensor should be used to accurately track complex human movement sequences, which may compromise application in real scenarios.  
Inertial sensors have been used by [45] in a previous project, Active@Home, to track the movements of the upper and lower limbs. To interact with the game, users had to point to the screen (like a cursor), or perform multidirectional steps (to interact with motor-cognitive games). Older adults had some difficulties alternating interaction with the cursor and the with the feet. The usability study also revealed some difficulties in visualizing movement feedback elements (while following an avatar), although these elements were placed as close as possible to the main action of the game [45]. The movements of the avatar were very clear and easy to understand. Due to the position of the sensor at the ankle, multidirectional steps could not always be correctly evaluated, which caused some frustration. The usability study recommended the inclusion of in-game design strategies to support interaction and autonomous use [45].  
A freeware dance program, StepMania, was combined with pelvic floor muscle training, achieving some promising results [48, 53]. The game required users to step in the direction of the arrows that reached the top of the screen; pelvic floor muscle contractions were represented by a red dot incorporated in the sequence of arrows [53]. The study did not include any gamification or game design concerns [48, 53]. In [37], the pelvic floor muscle training was provided resorting to an adaptation of a Wii Fit Plus(tm) exergame. Women would sit on the Wii Balance Board, and interact with the exergame resorting to pelvic movements. This intervention promoted a decrease in urinary symptoms; however, usability and game experience were not evaluated [37].  
In [44] an augmented reality exergame was developed that combines a representation of the user body with a virtual environment. In [31], a virtual reality approach is employed, in which participants are required to wear virtual reality glasses. Although virtual and augmented reality promises many benefits for older adults, the use of these tools is still challenging due to lack of access and digital skills [54].  
When designing exergames for older adults, the contents, mechanics, and interface of the exergames need to be tailored to the target group, considering their specific characteristics. Exergames designed specifically for older adults (as is the case of some of those presented in Table 1) incorporate some of the best practices for designing for older adults. Feedback, progression, time constraints and scores are considered particularly relevant for older persons' perceived performance while holding a training session [43]. Training principles such as feedback, optimal challenge and progression, and variety are also required for an effective training [23, 38, 49].  
To improve training variety, studies usually integrate multiple exergames that target different components of the training. However, individual training times (of each training component) cannot be personalized, leaving it up the player to control training times as instructed by the clinician or researcher [48, 49, 50]. Current exergames offer no solutions for the simultaneous (multicomponent) training of mobility limitations, cognitive impairment, and urinary incontinence, even though these impairments frequently coexist in older adults.