Wake Up Your Obliques With the Diagonal Side Sit

Core strength and stability are built with movements like this, not trying to balance on a BOSU ball.

What’s a powerful way to skyrocket your power and strength? Introduce unusual movements that safely challenge your stability. Movement variability is key to preventing injuries and avoiding the dreaded training plateau.

Your body adapts to stressors quickly. That it’s job. If it wasn’t good at it, you would get hurt all the time. Putting your body into different positions while challenging, controlling, and generating force is the secret to reaching your fitness goals.

Stability and the Nervous System

Stability is the ability to control force. Paul Chek says, “stability always precedes force production.” Mobility doesn’t do you any good if you can’t control it. A body with great mobility and no control is like a car with nobody behind the wheel. You need to be a smart driver who is always in control; riding close to the edge but not over it.

A lot of people think that the point of stability training is to put themselves into extremely unstable positions. Trying not to fall during an exercise doesn’t translate into making you stronger and more powerful. Standing on a BOSU ball while swinging a kettlebell doesn’t mean you are getting more stable. You may think it looks cool (it doesn’t), but if you force your nervous system into survival mode, it puts the brakes on building strength. The brain asks, “Is giving you strength right now a good idea?” When threat is on board, the answer is no.

Enter the Diagonal Side Sit

Power lives in the transverse (rotational) plane. Rotational force trumps all other planes. The transverse plane is a combination of the sagittal (forward and backwards) and coronal (side to side) planes. The more points of contact you have with the floor while tapping into the transverse plane, the faster you gain strength. These contact points give your nervous system a sense of safety. And when your nervous system feels safe, it will grant what you ask.

The multifidi (left) and rotatores (right) are small muslces that work in with the obliques to rotate the body around the spine.

The diagonal side sit is a perfect addition to your stability training program. It is a transitional position that will help you move from lying on the ground to a sitting position. It develops the rotational function of the abdominal oblique muscles, which control rotation of the torso in connection with the smaller muscles of the lower back, known as the mutifidi and rotatores:

  • Torso rotation to the left is from the right external oblique, left internal oblique, and right multifidi/rotatores.
  • Torso rotation to the right is the left external oblique, right internal oblique, and left multifidi/rotatores.

If you don’t own your obliques, you don’t own the transverse plane.

How to Do It


  • Use an anchored resistance band or cabled weight stack a few feet off the ground. Position it directly in line with your mid torso.
  • Your bottom thigh is perpendicular to your body, and your knee is bent and in line with your ankle. The top leg maintains a straight line from your shoulder, hip, and knee, and your knee bends 90 degrees.
  • Your downward elbow is below your shoulder and the palm of your hand is flat.

The Movement:

  1. Press the band/weight in front of your body over a count of four seconds.
  2. Hold for four seconds.
  3. Return to the starting position over a count of four seconds.
  4. Perform 12–15 repetitions, switch sides, and repeat. Complete two cycles per side.

Pro Tips:

  • Controlling momentum of the band/weight is a critical benefit to this exercise. Eccentric control builds strength.
  • Squeeze the glute of your top leg during the entire motion.
  • Do not grip the handle too hard. Feel the resistance in the midline, not the forearm.
  • Try to maintain a straight line from your head, shoulder, hip, and knee of the top leg.
  • Maintain a neutral head position or a slight side bend depending on your comfort level.
  • Remember to breathe.

Add a New Plane to Your Training

A stable core is important for everything in life, but most training protocols only train in the sagittal plane. Dynamic anti-rotation training makes you stronger and more stable in ways that conventional movements will not. The diagonal side sit also works cross-body connections of the shoulder to hip, improving walking and running patterns.

Add the diagonal side sit to your stability training and you’ll see improvements in strength and function. This movement can be integrated during any stage of training: before, during, or after.

See you on the floor.

More Movements to Challenge Forgotten Muscle Systems:

Teaser photo courtesy of Jorge Huerta Photography.

Anatomy photos courtesy of Wikimedia Commons.