**2. Background**

In the current literature, it is possible to find numerous studies that address the use of mobile devices as a means of encouraging physical activity. The authors studied the influence of apps that send motivational messages or messages that provide information on performing an exercise to the users' mobiles [34–39]. The results of these studies show that users' physical activity improves significantly, e.g., out of the 149 users in the case study [37], the group that used a mobile phone lost per month an average of 0.5 kg more than the control group. In a review, the authors analyze the effectiveness of using a Smartphone for the promotion of daily activity [40]. However, only 6 out of the 13 articles have recorded a change in the behavior of users. Recent studies conducted with patients in medical centers, measured the progress of patients in rehabilitation by counting the number of steps they walked daily, the doctor could then evaluate their progress by comparing these numbers [41,42]. These studies have demonstrated that with the use of a Smartphone and with the supervision of a medical professional, the patients' daily physical activity could be increased.

Moreover, social environments can also be very effective in encouraging exercise. In other study, the authors questioned whether it would be more effective to encourage physical activity through support among users as opposed to competition [43]. The authors demonstrated that social competition had a greater influence over users than the social support of their friends. Other authors describes a combination of an augmented reality game, such as Pokémon Go [44] with social interaction among users, which succeeded at increasing users' physical activity [45].

The use of video games or active video games (AVGs) as a means of promoting physical activity, has also been widely studied. Authors reviewed 52 articles which were focused on AVG systems in [46]. After the analysis of these studies, the authors pointed to an increased interest in light and moderate activities. However, these systems are not likely to produce any significant changes in sedentary behavior. Only the youngest part of our population could benefit from using AVGs but they are not considered to be an effective tool for increasing daily activity.

Recent studies, looked for solutions that promote active forms of transport, such as walking or cycling, with the use of Smartphone applications that monitor physical activity [47]. These authors' goal was to improve active transport and increase daily physical activity when commuting in the city [48]. Electric bicycles were viewed as a new method for promoting daily physical activity [49]. Authors looked at electric bicycles as tools that can benefit the health of elderly people and be a fun and practical way of incorporating exercise into their daily commute [50]. Moreover, authors studied the health benefits of swapping the car for an electric bicycle, especially when used for daily commuting [51]. Other studies analyzed security mechanisms for electric bicycle users, where the user's heart rate determined the level of assistance that was provided to them [52–54]. These mechanisms make it possible for people with health problems to use e-bikes safely.

After a careful analysis of the current literature, no studies were found on the increase of pedaling intensity over time in e-bikes. No relevant research has been conducted in this area. Thus, the proposal made in this study is novel as it is focused specifically on the area of e-bikes and on using them as tools for encouraging physical activity and increasing the intensity of exercise. Therefore, this work proposes a novelty among studies focused on promoting and increasing the intensity of physical activities, specifically for e-bikes. Consequently, this work makes the first reference to this field of study, with the aim of encouraging other researchers to address this problem.
