Side bends are a core exercise that involves bending the torso directly to the side, strengthening and stabilizing the trunk. This exercise is often performed standing, using only bodyweight or a light weight held in one hand. It engages the muscles responsible for side-to-side movement and maintaining upright posture. Developing strength in this area is important for overall core stability, which supports the spine and facilitates movement in daily activities.
Defining Lateral Flexion
The anatomical term for the side bend movement is lateral flexion of the spine, which occurs in the frontal or coronal plane of the body. This action involves decreasing the angle between the ribs and the pelvis on the side toward which you are bending. Lateral flexion is distinct from other spinal movements like rotation (twisting) or forward and backward flexion/extension.
The movement is facilitated by the articulation of individual vertebrae, primarily in the cervical (neck), thoracic (mid-back), and lumbar (lower back) regions. This ability to bend sideways is used every time a person reaches for an object on the floor or leans to the side to avoid an obstacle.
Proper Execution and Form
To perform a standing side bend, stand tall with the feet shoulder-width apart. The movement begins by slowly bending the torso directly to the side. Focus on isolating the movement, ensuring the hips remain stable and the torso does not rotate or lean forward or backward.
A common mistake is using two equal weights, one in each hand, which causes the weights to counterbalance each other, significantly reducing the muscular work required. When using a single weight, it should be held on the side toward which you are bending, or the opposite hand can be placed behind the head to increase the stretch.
The movement should be controlled, particularly when returning to the starting position, which is the eccentric portion of the exercise that helps build strength. Allowing the body to bend past the point where the muscles are actively engaged puts undue strain on the lower back and spinal discs. To maximize engagement, focus on creating length on the side opposite the bend and contracting the muscles on the side of the bend. Breathing should be coordinated with the movement, typically inhaling as the body bends down and exhaling as it returns to the upright position.
Primary Muscles Targeted
The side bend exercise primarily targets the lateral flexors of the trunk. The external and internal obliques, located on the sides of the abdomen, are major contributors to this movement. The obliques work synergistically to provide stability and execute the bending motion.
Another highly active muscle is the quadratus lumborum (QL), a deep muscle situated in the lower back. The QL is a powerful player in lateral flexion, and its contraction on one side helps bend the spine laterally. The erector spinae group, which runs along the length of the spine, also assists in controlling the movement and maintaining posture throughout the exercise. Strengthening these lateral muscles improves core stability, which is necessary for resisting forces that try to push the body off balance.