Walking backwards is challenging because you have to use your proprioception to feel the space behind you. We rarely walk backwards so it feels odd. It is an effective way to train the back side of the whole leg and spine. Lead the walk with the back part of your trunk. Sense the head and spine moving over the back reaching leg. This is a challenge to keep your pelvis upright not tipped forward and leading with your rear end before the head and spine. Be careful of the environement behind you. Be sure you will not walk into an object or worse yet a hole! We can expereince fear by walking backwards. If you know it is safe, then you will be less fearful or not fearful at all. Try this if you experience quadriceps and lower back tension while hiking. When I hike up a steep incline, and feel the tension, I walk backwards for a while. The feeling is amazing when you turn forward again. I experience an acceleration from the power of the back of my hips and legs. Try it some time!