Muscle imbalance refers to two opposing muscle groups in which one group is stronger or weaker than the other group. This is analogous having better balance when you ride a bike with one hand on each side of the handlebar than with one hand only. Corrective exercise can help restore better balance between both muscle groups as well as adjacent muscle groups that may affect the muscle imbalance.
Muscle Imbalance Types
Fitness professional Anthony Carey identified several types of postural imbalances that may increase your risk of pain, which include anterior pelvic tilt, posterior pelvic tilt and kyphosis with forward head. (Ref 1) The anterior pelvic tilt can be caused by tight hip flexors and rectus femoris on the thigh, causing the pelvis to tilt forward, which increases the extension in the lower back and lifting the buttocks. The posterior tilt is the backward tilt of the pelvis, reducing the lower back extension and the curvature of your buttocks. Kyphosis is the excessive flexion of the upper spine, which is often accompanied by the protrusion of the head and shoulder protraction.
Role of Corrective Exercise
Corrective exercise is often used by physical therapists and exercise professionals to restore the function and balance of the muscle groups. For example, stretching the chest and abdominal muscles and strengthening the back and posterior muscles are usually recommended for clients with kyphosis. Each postural and muscle imbalance requires different sets of corrective exercises to reduce the severity of muscle imbalances. Therefore, there is no one-size-fits-all approach to address muscle imbalances.
Effectiveness of Corrective Exercise
The corrective exercise method can help improve muscle imbalances and posture. In a study performed at the University of Tehran in Iran, subjects who participated in the comprehensive corrective exercise program that addressed the entire body for 12 weeks had a significant improvement in their kyphotic posture than those who performed local corrective exercises that address only the upper body. In another study published in "Clinical Rehabilitation," researchers at Cairo University in Egypt found that a combination of corrective exercise and traditional rehabilitation methods can help teenagers suffering from scoliosis to improve their posture and function.
Correlation Doesn't Imply Causation
Like any medical or exercise method, corrective exercise may not work for everyone. Physical therapist Mike Reinhold states that some people can have muscle imbalances that are caused by disease, pain, structural abnormalities and neurological problems in the nervous system. Therefore, no amount of corrective exercise intervention can address muscle imbalance. Some research shows that there is little correlation between muscle imbalances and poor posture with pain. A study published in the September 2002 issue of "The Journal of Orthopaedic and Sports Physical Therapy" showed weak abdominal muscles, pelvic tilt, leg-length discrepancy and the magnitude of the lower spine lordosis weren't associated with low back pain among 600 participants.