Machine Torso Rotation

A torso rotation machine provides resisted rotation of the torso to activate the oblique muscles. This exercise is performed kneeling on the machine while rotating your lower body to one side against resistance. The concentric and eccentric portions of this exercise entail rotation of the vertebral column.

The purpose of the torso rotation machine is to strengthen the oblique muscles while promoting the hypertrophy (increases in size) of this muscle group.

Promoting hypertrophy of the oblique muscles with trunk rotation helps define the surrounding area adjacent to the “6-pack” of the rectus abdominis. Training the obliques is essential to abdominal muscle aesthetics. Torso rotation also activates lower back muscles to stabilize the movement.

Strengthening the oblique muscles offers protective effects for the lower back as the obliques aid the lower back when bending over and bending sideways. The resistance of the machine elicits oblique activation throughout the entire range of motion. Stronger obliques also complement exercise and sports performance as they can contribute to biomechanical efficiency (e.g. rotation) during physical activity and exercise.

The abdominal wall is made up of broad, flat sheet-like muscles that are layered. The oblique muscles are essential to trunk rotation (as with trunk twists) and lateral flexion of the vertebral column. They surround the rectus abdominis on both sides. The external oblique muscle runs downward and medially and forms the inguinal ligament of the groin area. Its origin is at the outer surfaces of the lower eight ribs and it inserts into the linea alba via a broad aponeurosis. Some of the fibers of the external oblique insert into the pubic crest and iliac crest.

The internal oblique, as its name suggests, is located below the superficial external oblique. Its fibers run in an upward and medial direction. Its origin is located at lumbar fascia, iliac crest and inguinal ligament. Its insertion is located at the linea alba, the pubic crest and the last three or four ribs.

The rectus abdominis aids the trunk twist by rotating the lumbar region of the vertebral column. It is a vertical muscle that extends from the pubic crest and symphysis (at the pelvis) to the rib cage (xiphoid process and costal cartilages of ribs 5-7). The rectus abdominis is segmented by three tendinous intersections that run horizontally across the rectus abdominis. This tendon outlines the “6-pack” of the rectus abdominis along with the linea alba, a tendinous seam that runs down vertically, dividing the “6-pack” in half.

The transverse abdominis is the deepest muscle of the abdominal wall with fibers running horizontally. This stabilizing muscle compresses the abdominal contents. Its origin is located at the inguinal ligament, lumbar fascia, iliac crest and the cartilage of the last six ribs. It inserts at the linea alba and the pubic crest.

This exercise also requires stability from the back muscles. The quadratus lumborum forms part of the posterior abdominal wall located in the lumbar region (lower back). The iliocostalis is the most lateral of the erector spinae back muscles. It extends from the pelvis to the neck.

Trunk Twists.

The obliques are constantly assisting the lower back and abdominals with physical activity. This machine, however, is limited in its benefit and activation of the obliques. The resisted motion within the confines of the machine can also place the spine in a compromising position as the trunk rotates. It’s important to note that this exercise should be performed with a light weight to prevent risk of injury.

It is best to target obliques with other exercises that maintain the spine in a stable position (e.g. trunk twists, oblique crunches, oblique cable crunches) while further activating the obliques.

Returning the weight to the starting position too quickly can threaten the integrity of the spine. It is important to control the concentric and eccentric portions of this exercise.

It is important to note that exercise machines, in general, may not accommodate ergonomically to the varying heights, torso lengths and limb lengths of individuals. Adjust the kneeling pad height accordingly and ensure that you do not compromise the safety of your back against the weighted resistance.

When incorporating oblique training into your exercise regimen it is important to evaluate what other exercises you are doing in that training session. For example, it may not be best to train obliques on the same day as performing deadlifts and squats as the obliques work to stabilize the lower back. Training obliques before or after a training session that involves smaller muscle groups (e.g. calves, biceps, triceps) may be suitable, as it will not interfere with the quality of the overall training session.

While performing oblique exercises with added resistance can improve strength gains, increasing the weight beyond the lifter’s capacity can result in injury to the abdominal tissue or lower back.