In my younger days, I could reach right back and grab my heels! Today, I struggled to maintain this position with my hands protecting my lower back as shown. My quads, abdominals, and pectorals were screaming to release! I had no idea that my body was so rigid in the front. That is good information and will do this pose more often!
As Kris instructed, I kept my chin tucked, keeping my neck in neutral rather than extended like the model. For me, that option is safer and it’s easier to breathe.
I strongly encourage you all to give this pose a shot and see what you discover about your own anterior muscles. Or better yet, do the whole class! All you need is a yoga block and your own amazing body.