In the image, I’m moving into a descent. My front wheel is on what I call the ‘horizon line’ which is essentially the beginning of the descent. I’m moving forward toward that horizon line with my knees, not my hips. This will create elbow bend and keep me centered over the bottom bracket (where the cranks attach to the frame).
Here, I’ve started into the descent. After moving forward toward the horizon line and getting a glimpse at the descent, I’ve moved forward a little more at the knees to give myself enough potential arm extension for the descent I’m on. From here I’ll simply relax my arms, allowing them to extend as needed.
In this frame you can see that my arms are pretty stretched out. I’ve used the elbow bend I had in order to allow this to happen without running out of space. Had I not moved forward at the top of the descent, I’d be pulled forward by this portion of the hill, since I’d be out of room in my arms. Notice that my body mass is still centered over the bottom bracket which will is where I want to be as my bike meets the hole at the bottom of the first part of this descent.
In this frame you can see how the flatter portion of this descent has positioned me right over the center of my bike. This is because I set myself up properly coming into the initial portion of the hill. This descent continues on. Note that I’m essentially ‘back to neutral’ here even though I’m still on the descent. I’ll repeat the same process I’ve just completed for the upcoming portion of this descent.