A person’s posture and their body motion are not symmetrical, but as long as they are not falling down, their body is balanced. If the person is standing, their posture may be distorted, and their muscles may be working harder than they should be to hold the person up, but they are mechanically balanced. Our bodies would fall forward without muscles pulling us back. Keeping your balance is unconscious most of the time, but constantly staying upright has very real effects on the Contracting, Connecting and Control motion systems.
The Contracting System: Standing and Shifting muscles work together and in a miracle of coordination choreograph together to balance the body for smooth motion. Weak posture commonly begins with the combination of tight and short standing muscles coupled with weak, overstretched shifting muscles.
The Connecting System: The bones of the Connecting system form our framework, and are held together at joints by ligaments. Joints are floppy by themselves, so we contract our muscles to stabilize them as we move each joint through its normal range of motion.
The Control System: The entire Control system, the brain, spinal cord and the nerves are constantly working to keep us upright. In order to balance, our brain integrates information from three major sources to know where our body is in space, and to control it moment by moment as the center of balance shifts with motion:
1. The eyes (visual sense)
2. The ears (vestibular sense)
3. Muscle and joint position sensors (kinesthetic sense)
The position of the line of gravity, which is determined by the distribution of body weight, is important in determining the degree of muscular activity involved in maintaining all phases of posture. The line of gravity extends superiorly through the junctions of the curves of the vertebral column and inferiorly in a line posterior to the hip joints but anterior to the knee and ankle joints. When a person is in the easy standing position, the hip and knee joints are extended and are in their most stable positions. Because the line of gravity passes posterior to the hip joint and anterior to the knee joint, the weight of the body tends to hyperextend these articulations. At the hip this is resisted by the iliofemoral ligament and at the knee by the ligamentous apparatus of the knee and the action of the hamstrings. Similarly, the generally anterior carriage of the weight of the body tends to cause dorsiflexion at the ankle joint, and this is resisted by contraction of the calf muscles. These muscles, along with paraspinal muscles are the only absolutely essential muscles for maintenance of the upright posture.
The brain assumes we are balanced when we sense equal stress on both sides of the body. When there is an injury, the body will compensate and move differently to avoid pain. Over time, the body will adapt. Even if there is no continued pain, unbalanced patterns of motion persist. The human body still must balance to stand. So, the brain adapts and adopts new muscle and joint positions. We believe we are standing straight because our brain is being told by our senses that we are balanced, even though the mirror shows we are not.
Our bodies and our muscles work best when they are worked, and then allowed to rest. When muscles are not rested they become tight, resulting in the chronic “tension” which plagues people who don’t move their body. Your body has a need to move. If you are typing at a computer for an hour, when you stand up your first instinct is to stretch. When people undergo surgery, they are now required to get up and move around as soon as possible. Studies show people heal much better when you get them moving. When you think about it, exercise in general is simply moving your body. In addition to the obvious muscular and cardiovascular benefits of moving, motion and physical activity pump vital fluids within the body. Cells and tissues with little direct circulation receive nutrition and have their waste products removed by the physical compression and stretching that occurs with motion and exercise.
In athletes, dynamic posture allows the body to maintain normal length-tension relationships among its muscles while the activity is being performed. This leads to the optimum ability to reduce and produce force. For example, the optimum posture for acceleration is the triple extension of the ankle, knee, and hip. This posture allows the body to exert maximum force against the ground to propel the athlete forward. Proper dynamic posture also leads to coordinated movement. Each posture in movement is a momentary alignment of body segments, and successful movement is determined by the ease of transition from each posture to the next. If one segment or link in the kinetic chain is out of sync, there is potential for a performance error or injury.
Posture is clearly an integral part of many aspects of movement. In fact, I believe that dynamic postural alignment and subsequent dynamic muscle balance are fundamental movement skills. So it should be no surprise that a training regimen for good posture is very similar to any functional strength and conditioning program. We need to train strength, flexibility, balance, and movement. We need to incorporate multi-joint and multi-plane work with high proprioceptive demand. We need to target deficiencies with remedial work whenever warranted. The four primary anti-gravity muscle groups are: the gastroc/soleus group, the quadriceps group, the glutes, and the erector spinae group. When the body is upright, as is the case in most sport activities, the anti-gravity muscle groups work in conjunction with other muscle groups to maintain upright posture. These muscles act on information from three major sensory systems in the body: the proprioceptive, vestibular, and visual systems. Therefore, movements that work these muscles must be given prime consideration in a conditioning program. Tight muscles can contribute to poor dynamic posture, so a sound program of functional flexibility that addresses the target muscles must also be part of the athlete’s daily routine.
