# Examining the Efficiency of Electric-Assisted Mountain Biking across Different Types of Terrain  
[PERSON]  
1 Faculty of Sport, University of Ljubljana, 1000 Ljubljana, Slovenia; [EMAIL_ADDRESS] (M.S. ); janez. factors helped to raise the popularity, including improvements in battery and motor technology, coupled with innovative industrial design, which contributed to the greater range and enhanced performance of E-bikes [6; 7; 9; 10]. E-bike users have reported advantages such as higher speed with less effort and reduced travel time compared to conventional bicycles [5; 6]. The combination of higher average speed and lower power output indicates that electric-assisted bikes can provide cyclists with a more efficient and less strenuous experience [11]. Some studies have compared cycling with or without electric assistance and found that e-biking was faster and less intensive than conventional bicycling especially on the hilly route [9; 12]. [PERSON] et al. [13] investigated the effects of three different power assistant modes on physiology. They found that all three power settings contributed to meeting minimum physical activity requirements. Even with electrical assistance, riders achieved the necessary physical activity intensity of 3-6 METs. The MET concept represents a simple, practical, and easily understood procedure for expressing the energy cost of physical activities as a multiple of the resting metabolic rate [14]. [PERSON] et al. [2] found that E-bikes provide moderate physical activity (MET \(>\) 3) on flat segments and downhill segments and vigorous physical activity (MET \(>\) 6) on uphill segments. Absolutely, maintaining a certain level of physical activity intensity is important for various aspects of fitness and training, including in the context of sports training. When considering the use of electrical assistance, such as electric bicycles, in sports training, it is important to ensure that the assistance is used in a way that still provides the intended training benefits. E-bikes also have the potential to be used by amateur or professional cyclists. For example, in 2019, electric-assisted mountain bike racing took a sanctioned spot at elite-level events. The first-ever elite World Championship was held during the 2019 UCI Mountain Bike World Championships. This type of race takes place on varied terrain and includes rocky trails, technical singletrack, and open forest trails. It is characterized by frequent obstacles such as jumps and vertical drops coupled with high-intensity, high-performance uphill sectors. Interestingly, physiological variables (heart rate, respiratory frequency\(\ldots\)) remain elevated during descents, although the workload is significantly lower in these sections [15; 16]. There is a lack of studies to systematically evaluate and compare the physiological aspects of riding electric-assisted and conventional mountain bikes, particularly in relation to different types of off-road terrain, including technically challenging sections, descents, and flat terrain [1]. As part of our research, we will comprehensively examine off-road cycling, with participants riding various types of terrain common to mountain biking at high intensity. In our study, we will conduct an in-depth analysis of off-road cycling. This will involve participants navigating through a variety of terrain types common to mountain biking while exposing themselves to high physiological intensity. The inclusion of a wide range of terrain and high intensity sets our study apart from previous research. Therefore, the study aimed to compare and characterize performance-related parameters for riding electric-assisted and conventional mountain bikes. The study was designed to test the hypothesis that the use of an electric-assisted mountain bike would result in significant differences in performance over varying terrain. These differences were anticipated to be most noticeable on climbs, while less pronounced differences were expected when navigating technically challenging terrain and descents.