The other day at the gym, I heard one of the personal trainers say to a client while doing the back extension exercise on a fixed machine, "Never roll your spine forward when doing this exercise." My question is, what is the proper way to perform the back extension exercise? I have read both schools of thought on this exercise: one obviously being to always keep your spine in a neutral position throughtout the movement and the other to perform the exercise by actually curling the spine down and uncurling back up vertebre by vertebre back to a neutral position at the top.
Great question. I understand the confusion. The great news is both “schools of thought” are correct. It depends on what the trainer is trying to accomplish. For example: If you are extending on a back extension bench without spinal motion, you are emphasizing hip extension, therefore placing a greater stimulus on the hip extensors (biceps femoris, semitendinosus, semimembranosus, gluteus maximus, gluteus medius and adductor magnus). If you decide to “lock in” the hips and emphasize spinal flexion-extension, you will emphasize the spinal extensors (spinalis, longissimus, iliocostalis, multifidi, rotators, semispinalis, quadratus lumborum). Therefore, a variation may include both hip extension and spinal extension, allowing a better load transfer through the kinetic chain. With all this said, I would still encourage a more functional approach to this exercise, like standing extension without outside support (the bench). This will give you a better carry over to life movement.
Please remember: An exercise is nothing more than a movement performed repetitively under resistance. Therefore, don’t be fooled by all the rules that exist. Just analyze the motion being performed, the resistance being applied and make it fit your client’s goals, needs and ability level. Be safe, have fun and good luck!