Back extensions on a machine can help strengthen your lower back tremendously, or referred to as the
lumbar spine, to help accomplish your everyday activities. For me, this exercise is critical to help me keep my back strong and resistant to injury throughout my lifetime hopefully. I have an abundant amount of back exercises I do in order to maximize my back strength and to keep my body guessing so it will build more strength in the end. This exercise is pretty self-explanatory based on the picture below and adding this workout to your routine will be a great asset.