When I say training the core most people think about performing endless crunches or holding a plank forever. One of the most important, and often neglected, movements of the trunk is the rotation. Even though we tend to perform this movement several times during the day without noticing, this movement is not target properly in the gym. Let’s take a look in the muscles involved and a few exercises option to get you stronger in this plane of movement.
Trunk rotation refers to the rotary movement of the spine on the transverse plane. The human spine is composed by seven cervical vertebrae (neck), 12 thoracic vertebrae (chest), five lumbar vertebrae (lower back), the sacrum (lower back), and the coccyx (tailbone). These bony structures are separated by intervertebral disks that act as shock absorbers and allow movement between the vertebrae. Each vertebra is capable of moving in three directions (back and forth, lateral flexion, and rotation), and even though the movement at each joint is small, the spine as a single structure has great flexibility and range of motion. Because the pelvis is attached to the vertebral column, spinal movements are usually transmitted to the hip bones.
Most of the movement from spinal rotations comes from the thoracic and cervical regions. However, the ribcage attachment at the thoracic level limits mobility. Rotation is also limited at the lumbar region because of the size and shape of these vertebrae.
Spine rotation is performed during many daily activities and sports. For instance, when you are seated in your car and you reach for the seatbelt above your left shoulder you are performing a rotational movement. Driving a golf ball or hitting a baseball are examples of spinal rotation during sports events.
The muscles involved in trunk rotation movements are part of the core structure of the body. Our core is composed by muscles of the back, abdomen, hips, and pelvic floor, which are responsible for body stabilization during movement and the maintenance of posture and body alignment. A strong core can improve performance of activities of daily living and sports, and play an important role on injury prevention.
Trunk rotation is performed mainly by the abdominal oblique (external and internal) muscles. The “obliques” are located on both sides of the trunk in the abdominal region, connecting the ribcage to the pelvis. When the pelvic bones are stabilized, the oblique muscles pull the ribcage towards the hips, creating a rotational movement of the whole spine.
On posterior region of the trunk, the erector spinae muscle group and the iliopsoas muscle group work in synergy with the oblique muscles. Also, deep and tiny muscles connecting one vertebra to another rotate each vertebra individually.
Trunk rotation drills are examples of functional training exercises because they tend to mimic movements of common daily activities. These exercises are meant to strengthen the core muscles. During these exercises, even though the prime movers are the oblique muscles, many other muscles are engaged in order to stabilize the body and keep good form.
Below you will find a few exercises to train those muscles in a functional way.
- Broomstick twists
Standing with your feet hip-width apart, hold a stick behind your upper-back. Keep pelvis stable while you slowly rotate the upper-body from side to side. Contract your abdominals and buttocks to maintain a neutral spine.
This is a good exercise for beginners because there is no load (weight) on the spine, which is appropriate when one is learning a new movement. Perform this exercise in a slow and controlled manner for best results. Long sets (20 repetitions or more) may be adequate.
- Seated trunk rotations
Sit on the floor with your legs bent in front of you. Hold a medicine ball or a light dumbbell with both hands, keeping it close to the chest. Engage your abdominals, and rotate the upper-body to one side, keeping your back straight. Come back to center and repeat to the other side.
This is also a beginners’ exercise, and you should strive for a slow and controlled motion. Light weights are more appropriate than heavier loads. When you feel you are ready for more challenge, try leaning backwards while keeping your abs tucked and your back straight. Another option is to lift the feet from the ground, balancing on your buttocks.
- Walking lunges with twist
Stand with feet close together, holding a medicine ball or dumbbell with both hands. Keep your elbows bent and the weight close to your chest. Step forward with one leg, and slowly lower the hips down by bending the knees. Your knees won’t touch the floor. Find your balance, and then, slowly rotate your torso towards the extended leg (the one on the back). Don’t extend your arms, and keep your core engaged. Rotate back to center and extend your knees as you come back to standing. Step the back leg forward, and repeat the drill. Walk in a straight line, alternating sides.
This is an intermediate exercise, and walking lunges should be mastered before attempting this drill. Choose light weights and perform the exercise in a slow and controlled manner for safety reasons.
- Wood chop
Stand with your feet hip-width apart, and hold a medicine ball with both hands. Squat down while you rotate your hips and arms to one side, bringing the ball closer to your foot. Slowly, stand up at the same time as you rotate your hips and arms to the opposite side, bringing the ball above your opposite shoulder. Perform 10 to 12 repetitions, and then, change sides.
This is an advanced movement and should be performed with caution. Use light weights and perform the movement slowly until you master the exercise. Keep your core engaged at all times to protect the back.
- Ball Russian twist
Sit on a stability ball with your feet planted on the floor. Slowly lean backwards on the ball until your upper back is supported and your knees are bent in a 90 degree angle. Push your pelvis up to maintain back support. Extend both arms in front of you – hands pointing to the ceiling, and palms touching. This is your starting position. Slowly rotate your torso to one side, while keeping your feet grounded and your pelvis tucked. Roll back to center and repeat to the other side.
This is an advanced exercise which requires some core strength to be performed. Abdominals and glutes should be engaged at all times in order to maintain balance and protect the spine.