Learn safe and effective trunk rotation exercises that target the external and internal obliques using the dual cable cross machines at the ARC.
Rotation tends to be one of the most neglected actions when training the core, and when it is performed it is often done incorrectly. The focus of this article is safe and effective trunk rotation exercises that target the external and internal obliques. The most important consideration when choosing core rotation exercises is available rotation range of motion in the three regions of the spine. The anatomy of the spine allows for the most rotation to occur in the cervical (neck) region (~60°). The thoracic spine is the runner up with ~30-35° of available rotation. The lumbar spine is built for minimal rotation and thus rotation should not be encouraged in this region. The most important rule of thumb for safe exercises in the gym is that no exercise should violate the biomechanical integrity of the joints. When performing torso rotations, adhering to these ranges is advised to avoid placing undue stress on the intervertebral joints and discs. The outdated seated torso rotation machines that still lurk in many gyms are an example of potentially dangerous exercise that too easily violates the correct rotation range of the spine. If these machines are not set perfectly for each individual, the pivot points of the machines may encourage rotation in the lumbar region of the spine instead of the thoracic.
Performing safe and effective exercises for the core requires a bit of knowledge about the anatomy of the spine. The spine can perform four actions: flexion, extension, lateral flexion, and rotation. The way you choose to incorporate these actions in your training program is fundamental to maintaining a healthy back. The ultimate goal should be to keep the muscles on all sides of the trunk balanced, mobile, and properly supporting the spine. The risk of injury is much higher when using machines for core movements because you run the danger of using the superficial movement muscles to do the work and allow the deeper spinal stabilizers to remain dormant. Exercises selected should encourage internal stabilization rather than external stabilization of the spine. Internally stabilized exercises require the body to recruit appropriate musculature to support and move the spine. Externally stabilized exercises (machines with a seat, chest pad, etc…) create, as well-known spine expert Stuart McGill, PhD eloquently states, a “proprioceptively starved” environment.
An important consideration is safe loading for the spine. While the ability to move through the full available range of motion is necessary for optimal function, loading these ranges of motion increases the risk associated with the exercise. Stuart McGill, PhD points out the inherent risk associated with twisting torque as compared to the action of trunk rotation. He cites the seated torso rotation machine (recently removed from the ARC) as being particularly dangerous for most athletes in his book Ultimate Back Fitness and Performance. Loading the spine with the large amount of weight available on the weight stack of this machine and moving through an unrestricted amount of rotation make using this machine a recipe for back injuries. In addition to the range of motion and load, most individuals have a hard time maintaining an upright, neutral spine when seated. Simultaneous flexion and rotation of the spine places these joints in an even more compromising position and is ardently contraindicated by many experts in the field. For an in depth explanation of the perils associated with these movements I suggest watching Charlie Weingroff, DPT’s Training=Rehab-Rehab=Training DVD’s.
So how can we get great obliques without sacrificing a healthy back? The dual cable cross machines at the ARC are a great option for safe and effective torso rotation exercises. Two great examples are the cable twist and the cable chop. These exercises are done in an upright position allowing for good posture and internal stabilization of the spine. The twist is a great place to start for a beginner OR anyone who does not train torso rotation regularly. Abide by the following cues for appropriate execution:
• Feet shoulder width apart
• Soft bend in the knees
• Cable handle held at chest height
• Stand with good posture (neutral pelvis, shoulders back, chin slightly tucked)
Begin by challenging yourself to hold an isometric contraction. Maintain your position holding the cable at chest height with no movement occurring through your trunk. If and ONLY if you are able to resist rotation torque in this position (you aren’t getting pulled toward the cable arm) should you progress this movement. Don’t forget to breathe! If this position becomes easy, try performing the same isometric contraction with your elbows completely extended. The longer lever length of your arms will increase the difficulty of the exercise. You can move your arms from the chest position to the extended position and back to add a dynamic component without leaving the isometric position. When you are ready for the most dynamic version of this exercise add a bit of rotation through your thoracic spine. Keep your pelvis aligned forward (hip bones like headlights). Move through your rib cage to bring the cable from hip bone to hip bone in a side to side motion. Do not move through a bigger range of motion unless you add movement at your feet to allow your pelvis to follow the rotation in your spine.
The chop is a more dynamic and complex version of torso rotation. This movement is more advanced and very functional. Chops can be performed from high to low or from low to high. The increased range of motion required for the chop forces you to learn correct movement at your feet so that your pelvis moves along with your spine. Do NOT rotate through your lumbar spine (lower back). When performing the high to low chop on the right side as shown in the video:
• Raise the cable arm to one of the highest settings (dependent on personal height)
• Step away from the cable arm and stagger your stance (foot closest to the cable arm is back, the opposite is forward)
• Use the balls of your feet as pivot points; rotate the opposite foot in the direction of your torso rotation (if the cable arm is on your right side then as you move toward it rotate your left foot and as you move away rotate your right foot)
• Exhale as you pull the cable across your body and inhale as you return
• Switch sides and repeat
The low to high chop is the opposite movement. Position the cable arm at one of the lowest settings. The rules above still apply but this time as you pull diagonally across your body you will move the cable from the low position to an extended position above your opposite shoulder. The fiber direction of the internal and external obliques is different. Performing both the high to low and low to high chops provides more variety and challenge to the musculature of the core.
The musculature that stabilizes the spine responds well to low loads and high repetitions. The most important role of the core musculature is to support your body in an upright, extended position. Watch the video for a visual demonstration of the technique and don’t hesitate to ask an ARC trainer or fitness intern to give you a few pointers if you are learning these movements for the first time.
Keep in mind that the only way to a defined abdominal region is a low body fat percentage resulting from a quality combination of exercise and nutrition. Regardless of aesthetic goals, training the core musculature is an essential component of every exercise program.
Article by: Sarah Kirtland, ARC Fitness Lead
Neumann, Donald A. (2010). Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation (2nd edition). St. Louis, Missouri: Mosby Co.
McGill, Stuart. (2004). Ultimate Back Fitness and Performance (4th edition).