What Muscles Does the Rotary Torso Exercise Machine Work?

The rotary torso machine, also called a torso rotation machine, targets the muscles of your core. However, if you use improper form or don't control the motion, the rotary torso machine loses its effectiveness.

This exercise strengthens your core muscles, but it will not specifically burn off fat from your midsection or sides.

Read more: Your Core Is More Than Just Your Abs — Here's How to Keep It Strong

The rotary torso exercise machine allows you to rotate your trunk against resistance. This movement targets your side abs, or obliques, as described by ExRx.net.

Rotary torso machines have different designs. You sit on most torso rotation machines, but you kneel on others. Some machines hold your legs in place while you twist your torso; other machines hold your torso in place while you twist your legs.

Some torso rotation machines have an integrated weight stack, while plate-loaded machines hold weight plates for resistance, as demonstrated by ExRx.net.

Regardless of the design, rotary torso machines target your core muscles. The obliques are the primary movers. They are responsible for spinal rotation — turning your torso to the side.

To target the obliques, you must rotate at the lumbar spine, not at the hips. Although the torso rotation movement targets your obliques, several other muscles, including quadratus lumborum, rectus abdominis and transverse abdominis, engage to assist your core and stabilize your torso.

For the best results, use the rotary torso machine properly.

1. Sit down and place your shoulders against the shoulder pads and lightly grasp the handles.
2. Select a weight that allows you to do eight to 12 repetitions.
3. Pull your bellybutton into your spine to activate your rectus abdominis, the main ab muscle, which helps brace your torso.
4. Exhale as you rotate to one side.
5. Pause for a count of one and then slowly return to center.
6. Perform each repetition slowly and with control.

Read more: Build a Core Workout Routine That Targets More Than Just Your Abs

Do not grasp the handles too tightly. If you do, you are more likely to use your arms to twist, which takes away from the work of your obliques.

Do not swing or perform the rotation exercise quickly or with momentum. It is easy to begin swinging back and forth with no control or purpose, but this does not benefit your obliques.

Using the rotary torso machine will strengthen and tone your oblique muscles, but it will not specifically burn fat off the area you are working.

Design a complete workout plan that incorporates strength and cardio exercise, in conjunction with a solid nutrition plan, if your goal is to lose weight and burn fat. The rotary torso machine should be one part of an overall exercise routine.

If you don't have access to a torso rotation machine, try this stability ball exercise, as demonstrated by the American Council on Exercise.

1. Lie with your upper back resting on the ball.
2. Keeping your torso straight, reach both hands up toward the ceiling and bring your palms together.
3. With your hips lifted, twist your midsection until you roll onto one shoulder.
4. Return to the center and rotate to the opposite side.