The first step in assessing core function is to observe the client’s posture when they stand, sit and move. Ideally the spine should be supported in a neutral position by good core muscle tone during all these activities. Excessive curvature in the lumbar spine (lordosis) or the absence of a lumbar curve (flat back) are potential indicators of poor spinal control. Often these extremes of spinal positioning are adaptations due to a history of back pain or injury, poor fitness (weak core muscles) and sedentary work postures like excessive sitting.
The core muscles link the spine, pelvis and legs together creating a posture and movement control system. For many people, including athletes, muscle imbalances can lead to poor posture and spinal control as well as poor movement patterns. Muscle imbalances occur when certain muscles are overdeveloped or overactive while the opposing muscles remain underdeveloped or under active. These imbalances create asymmetrical movement and spinal loading patterns. Cyclists for example can overdevelop the quadricep muscles and have underdeveloped hamstrings and gluteal (opposing) muscles. Strong, well developed quadriceps are essential for cycling. The problem is once the cyclist stands up and walks the overactive quadriceps tilt the pelvis forward increasing the curvature in the lumbar spine as seen in the illustration above. Strong, healthy hamstring and gluteal muscles contribute to good pelvis/spine positioning by counter balancing the force and movement action of the quadriceps. They are also essential for good walking and running function since these muscles are responsible for moving the hip into extension.
Sit to Stand Assessment
Another simple assessment of spinal control is to observe common movement patterns like sit to stand. Does the person bend (flex) their spine, or use their hands to push on their thighs to assist in standing? There are many factors that contribute to these movement compensations: poor eyesight (looking down), hip/knee pain, weak hips/leg muscles , back pain and poor overall fitness are possible factors. Further testing of muscle function and joint mobility often identifies specific soft tissue or joint structures that are compromised.
Lifting heavy objects is one of the most common ways people injure their backs. The sit to stand test also identifies how a person organizes their movement around lifting or squatting movements. Ideal spinal control during this test is demonstrated by the person on the left (A) side of the illustration. Engaging the back muscles stiffens the spin by locking the vertebrae into a more rigid load bearing structure. Engaging of the back muscles also engages the abdominal muscles creating a “corset” effect – 360 degrees of muscle activation.