# Examining the Efficiency of Electric-Assisted Mountain Biking across Different Types of Terrain
## 4 Discussion  
The purpose of the study was to compare and characterize performance-related parameters between electric-assisted and conventional mountain bikes. Highly skilled participants with previous competitive mountain biking experience cycled on a mountain bike course with different off-road terrains (i.e., uphill, downhill, flat section, technically demanding terrain) on electric-assisted and conventional mountain bikes. Physiological demands and energy expenditure were significantly increased throughout the mountain bike course when participants used conventional mountain bikes versus electrically assisted mountain bikes. There were significant differences in several physiological parameters and speed under different riding conditions. Of note, speed was significantly higher when riding uphill on an electrically assisted mountain bike. Most physiological parameters showed higher efficiency, lower heart rate, and lower oxygen consumption relative to power output while riding an electric-assisted mountain bike. This higher efficiency can be attributed to the electric motor, which assists the cyclist and reduces the physical effort required to ride uphill. As a result, less oxygen is needed to maintain a given speed and cover a given distance, which means improved cycling efficiency. The results showed that cyclists rode with an electric-assisted mountain bike on technically demanding terrain and ascents with a higher cadence, which can be connected to make it easier to adapt and improve the technique on this terrain, even when replacing an electric-assisted mountain bike with a conventional mountain bike. Due to the significantly higher speed of riding uphill on an electric-assisted mountain bike, cyclists also had to exert more power to resist air drag. However, there was also a significant difference in the power required to overcome gravity not only at the expense of the weight difference but more importantly at the expense of the difference in riding velocity with the electric-assisted mountain bike when going uphill. E-bikes also have electric motors that assist the rider and make it easier to accelerate and maintain speed. The motor provides additional power during acceleration, reducing the effort the rider requires. As the results of the study show, when riding uphill, it becomes evident that the cyclist expends reduced pedaling effort. Some physiological and power output differences occur when riding downhill, on a flat section, and on technically demanding terrain. Some explanations might also be that the bike's weight, where the electric-assisted mountain bike was 7.5 kg heavier than a conventional mountain bike. Some previous studies investigated the physiological demands of electric-assisted off-road cycling but were mainly focused on health-related issues. The benefits of the physiological demands were similar to our findings, where the intensity was significantly different between riding with electric-assisted power or no electric assistance [2; 9; 13]. When we compared different types of off-road terrains, we found that riding uphill was the segment where the most benefits of an electric-assisted mountain bike were apparent. Physiological measurements and power output measurements were shown to help provide insights into the physiological profile of off-road cycling in varying terrains with an electric-assisted and conventional mountain bike. During the uphill segment, the oxygen consumption level was significantly larger when riding a conventional mountain bike than an electric-assisted one. On the other hand, the smaller differences observed in the downhill and technically demanding sections could be due to several factors. One of these factors could be the effective use of the gear ratio during the ride. It is possible that cyclists more skillfully adjusted their gears on conventional mountain bikes while descending or riding through technically challenging terrain, thus maintaining comparable levels of effort and energy expenditure.