COMPENSATING FOR THE EFFECTS OF COMMON POSTURES
Given the broad definition of posture (any position in which the body resides), the number of postures Soldiers may assume is infinite. However, Soldiers assume the same few postures throughout most of the duty day. The postures can be categorized as the flexed posture (associated with sitting, bending forward, lifting, and crouching); and the upright posture (associated with standing, walking, marching, and running). The body will eventually conform to accommodate these postures. Some muscles will become over-stretched and weak, while others will tighten and lose flexibility. The resulting muscle imbalances will hinder natural movement and increase the likelihood of injury. It is important to regularly compensate for time spent in these prolonged postures by performing exercises or activities that restore the optimal flexibility of muscles and joints:
- Performing extension compensates for flexion. The most common posture for many individuals is seated. This posture is associated with flexion of the spine. Unless great effort is made to sit straight (or a roll is used to maintain the inward curve of the low back), the trunk tends to assume a C-shape. The longer this flexed posture is assumed, the greater will be the effect on muscles around the trunk. The back muscles and ligaments become over-stretched and weak, while muscles on the other side of the trunk (for example, hip flexors) get tighter and pull the pelvis into an unbalanced position. The Soldier on the right in Figure C-6 is in a flexed position. Compensation for prolonged time in this position would occur if the Soldier assumed the prone position of extension demonstrated by the Soldier on the left. To prevent the imbalances associated with too much flexion, Soldiers should regularly perform extension exercises and activities such as those shown in Figure C-7.
Figure C-6. Soldiers in the flexed (right) and extended (left) postures
Figure C-7. Performing extension to compensate for flexion
- Performing decompression. This compensates for many of the compressive forces that act on the body throughout the day. Many Soldiers spend the majority of their day on their feet. The weight of the body and equipment creates a compressive effect on the spine and other weight-bearing joints. In fact, at the end of the day enough fluid will have been compressed out of the spinal discs that height measurements will usually indicate that Soldiers are noticeably shorter. Joints that are overly compressed may eventually compromise mobility. To compensate for compressive forces on the spine, it is useful to perform exercises or activities that decompress as shown in Figure C-8.
Figure C-8. Performing decompression to compensate for compression