What role does body positioning play in maintaining stability and control on electric mountain bikes, particularly when navigating technical terrain or high-speed descents? How does the added weight and torque of the electric motor impact the riders ability to make subtle adjustments to their body position, and what techniques can be employed to compensate for these differences? Is it more effective to focus on shifting weight over the bike, or to rely on subtle adjustments in knee and elbow angle to maintain control? Additionally, how does the increased speed and acceleration of electric mountain bikes affect the optimal body positioning for cornering, and what adjustments should riders make to their body position when transitioning from a traditional mountain bike to an electric model?