How to Do a Machine Back Extension

Proper Form, Variations, and Common Mistakes

Targets: Lower back muscles

Equipment Needed: Back extension machine or Roman chair

Level: Beginner

The back extension machine or Roman chair is used for an isolation exercise that targets the lower-back muscles, mostly the erector spinae. You lock your heels under a pad or roller, with another pad to support your lower body as you recline face-down. This facilitates flexing at the waist. 

The exercise requires that you bend at the waist, and a little at the hips, lowering the torso until approximately upper and lower body form a right angle. The extension is usually performed as a bodyweight exercise, using only the upper body for the load. The use of the back extension machine is controversial as poor technique can result in an injury. It can be part of a strengthening program.


Back extensions are done when you want to strengthen the lower back. They complement abdominal exercises by providing a reverse movement of the core muscles compared to crunches.

The back extension machine targets the erector spinae, which are three muscles: illiocostalis lumborum, longissimus thoracis, and the spinalis. This bundle of muscles lies in a groove along the vertebral column. These muscles extend your lumbar spine. Synergistic muscles used in the back extension are the gluteus maximus, hamstrings, and adductor magnus. Stabilizer muscles used include the back, shoulder and neck muscles: biceps, triceps, lats, deltoids, traps, pecs, and rhomboids.

You use these muscles anytime you pick up an object from the ground. They are also key muscles in maintaining good posture.

Step-by-Step Instructions

Adjust the back extension machine so that your feet are securely hooked under the foot pads. You need to ensure a good fit so that you are held firmly when you start the bend at the hips. Position your lower body across the large pad provided for this purpose. You need to be far enough forward so that you can flex the upper-body almost at right angles. Cross your arms beneath your chest.

  1. Brace the abdominals while holding the arms folded and maintaining the body in a horizontal position. Make sure the ankles are well anchored.
  2. Slowly bend at the waist until the upper body is at 90 degrees to the lower body. Avoid arching your low back and squeeze your glutei at the top.
  3. Extend to the starting position and stretch upward just slightly so that the back is in hyperextension. Avoid arching your low back and squeeze your glutei at the top.
  4. Try three sets of five repetitions—more or less depending on the condition and strength of your back and abdominal muscles.

Common Mistakes

Poor technique can lead to an injury when you use a back extension machine. Avoid these errors.

Too Fast and Jerky

You must keep your movement slow and controlled. Do not bounce or jerk. If you go too fast or you use any forceful motions you can strain your back muscles or compress your discs.


Only extend until your back is level with your thighs. Do not overextend your back.

Too Heavy of Weight

It is safest to perform this with only your body weight. If you add weights, select a light weight.

Too High of Training Volume

Keep the training volume low, such as no more than 10 repetitions for two sets.

Modifications and Variations

The back extension machine exercise can be performed in different ways to meet your fitness level.

Need a Modification?

Many trainers steer clients away from the back extension machine as they think the risk of strain isn't worth using it for an isolation exercise. Instead, they prefer compound or functional exercises such as squats, bent-over rows, and stiff-legged deadlifts to strengthen the lower back.

Up for a Challenge?

Adding a weight held at the chest, such as a dumbbell or plate, can provide additional work. A barbell can also be held behind the neck. However, additional weight brings a higher risk of injury and should only be done with caution.

Safety and Precautions

Do not use the back extension machine if you have a herniated disc. If you have any back problems, talk to your doctor or physical therapist to see whether this exercise is appropriate. Muscle engagement is the same as picking up a heavy object from the ground. If you have been told to restrict such activities, you should not use this machine.

One criticism of the back extension machine is that it isolates the lower back muscles too much so your other muscles don't assist to protect your back sufficiently. If you feel any back pain or discomfort when doing this exercise, stop.

Try It Out

Incorporate this move and similar ones into one of these popular workouts:

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Article Sources
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