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Measures to Prevent Profiles in Combat Support Commands

Soldiers on duty-limiting medical profiles offer reduced benefits to commands that provide logistics support to operations in Iraq. Medical limitations can prevent a Soldier from wearing body armor or driving, leaving fewer Soldiers to perform a steady workload. For units already undermanned, medical issues can compromise mission success.

Between March and August 2007, shoulder and back pain complaints among Soldiers of the 377th Theater Support Command were numerous. Because of the physical demands of the environment, many ailments became chronic despite rest and required physical therapy. Recognizing this injury trend, the command identified measures for preventing injury in order to reduce physical therapy visits and avoid lost work hours. Two areas identified as causing injury to Soldiers were ill-fitting body armor and misaligned vehicle seats.

Shoulder Pain and Individual Body Armor

Prolonged wear of the interceptor body armor outer tactical vest (OTV) is frequently blamed for common complaints of neck and shoulder pain. Thirty percent of the physical therapy referrals at Camp Arifjan, Kuwait, in March 2007 were related to pain caused by OTV wear. The OTV is being replaced in direct combat roles with a newer model known as the modular tactical vest, but the OTV is still issued to active duty members in ancillary roles, such as supply, transportation, and training commands.

The OTV should be worn tightly around the torso to protect core organs from some types of small projectiles. The vest, with two small-arms protective inserts, weighs approximately 17 pounds. The additional burden of side, shoulder, groin, throat, and neck pieces, plus the enhanced tactical load-carrying vest and individual equipment belt, can result in a total system weight of more than 60 pounds.

When worn tightly on the torso with minimal shoulder contact, the OTV attempts to distribute its weight along the surface area of the ribcage. If the vest is not adjusted correctly, the tactical load rests directly and disproportionately on the smaller surface area of the shoulders. Over a prolonged period, the weight of the system pushing down on the upper extremities can fatigue muscles, compress nerves, impinge on the shoulder rotator cuff, reduce available range of motion, and cause pain. Even if patients improved after a period of light duty and shoulder rehabilitation, many complained of pain after returning to OTV wear when their shoulders again became the focal point of weight distribution.

Positioning the OTV

During physical therapy evaluations, patients who donned a basic OTV under supervision demonstrated a distinctive pattern of errors in positioning the OTV that included—

  • Failing to initially release the side straps to assist with front Velcro alignment.
  • Adjusting the neckline flaps around the angle of the chin when looking down at the vest and not straight ahead.
  • Failing to adjust the vest off the shoulders and tightly against the ribcage.

These three factors lead to misalignment of the neckline and reduce the weight borne by the ribcage, placing the weight on the shoulders. Weight resting on the shoulders inhibits natural biomechanics of the upper extremity and causes pain.

When the OTV was readjusted onto the ribcage by the physical therapist, patient complaints of shoulder and neck pain generally decreased. To achieve this relief independently, Soldiers were instructed to—

  • Loosen the side straps each time the vest was put on.
  • Look up to clear the chin when aligning the neckline.
  • Lift the OTV off the shoulders with the thumbs.
  • Have a partner tighten the OTV against the ribcage.

In addition to one-on-one patient contact to review this technique, instruction on properly donning the OTV was presented during a safety briefing for the 337th Theater Support Command to company leaders. As a result of these proactive, preventive measures, physical therapy consults for neck and shoulder pain significantly decreased over a 4-month period. Clinical research has also been initiated to study the effect formal instruction on safe OTV-donning techniques has on the frequency of shoulder and neck pain in Marine Corps training units at Camp Pendleton, California.

Prolonged Compromised Posture in Vehicles

Complaints of lower back pain among Soldiers made up another 30 percent of the physical therapy visits at Camp Arifjan in March 2007. Although administrative workers reported such pain, the majority of patients were truck drivers who ran frequent missions into Iraq. Complaints included increased lower back pain with prolonged sitting, difficulty returning to a standing position, buttock pain, and occasional numbness and tingling in the legs. Conservative treatment included limited duty to modify activity and lessen symptoms. However, extended periods of light duty reduced the number of available drivers and became a concern for company commanders.

Back pain during prolonged sitting typically occurs when the natural curve of the lower, or lumbar, spine is reduced. In a normal spine, the natural curvature distributes a balanced load on the pliable lumbar discs, which expand and compress in response to force. With compromised posture, the lumbar curvature is reduced and the angle of force on the discs is altered so that the discs are unable to disperse force and are often pushed toward nerves in the lower back. Compounded by increased force from body armor, mechanical vibration, and shock absorption from unpaved roads, the resulting
long-term pressure on these nerves causes chronic lower back pain.

With assistance from the 336th Transportation Group’s safety officer, several vehicles used by these Soldiers, including the heavy equipment transporter (HET), M915 tractor, 5-ton truck, and M1114 high-mobility multipurpose wheeled vehicle (HMMWV), were examined for postural supports. The key factors determined to contribute to lower back pain included—

  • A poor relationship between the hip and knee height of the driver.
  • Low seats.
  • Poor curvature of the lumbar spine.
  • Excessively reclined backrests.

Sitting Correctly in Vehicles

When seated, the driver’s knees should be lower than his hips. The relationship between hip and knee height in a seated position often determines the presence of a natural curve in the lower back. When the hips are equal in height to the knees, the curvature of the lower back is reduced and the Soldier experiences a “slouch” in the lower back. This can occur when the driver seat is adjusted too low. A good example is the rear seat of an M1114, where the low seat combined with the lack of leg room results in the knees resting well above the hips. Curvature of the back in this extreme position is relatively nonexistent, and excessive pressure is placed on the discs of the lumbar spine, causing Soldiers to experience pain after prolonged periods of riding. The seat height should not be lower than the height of the lower leg of the person in the seat.

The lumbar curvature and the capability of the spine to absorb force efficiently are restored when the knees fall below the hips in the seated position. Sometimes this can be achieved by adjusting the height of the seat when enough headroom is available. It is most successfully achieved when the seat fully supports the thighs with a 5- to 15-degree slant below the horizontal. In vehicles like the newer-model 5-tons, in which the seat rest adjusts downward, the seat should be adjusted so that the knees rest below the height of the hips and a curve is evident in the lower back. This supported position allows the spine to absorb the shock of the road most efficiently. When interviewed, drivers noted less back pain when sitting in this position.

Current Department of Defense (DOD) seat standards for vehicle acquisition and procurement do not specify standards for seat rest adjustment below the horizontal. For this reason, many seat rests, such as those in the HET, M1114, and M915, do not adjust at all. Soldiers in these vehicles can sit on a pillow or seat wedge that creates an angle sufficient to achieve a relative curve in the lower back. The DOD Safety Office is working with SKYDEX Technologies, Inc., to develop a universal seat cushion for use in these vehicles. This product is currently in field testing.

Corrections to the seat rest angle are only effective when the backrest is 95 to 100 degrees from the horizontal position. Reclining farther requires the driver to reach farther forward to control the vehicle, reduces the lumbar curve more, and increases pressure on the vertebrae. Adjusting a backrest to an upright position, 90 degrees from the horizontal, does not fully allow for the bulk of the OTV and makes the driver pitch forward. Typically, 95 to 100 degrees for back rest inclination above the horizontal, combined with the seat rest slope of 5 to 15 degrees below the horizontal, is an anatomically comfortable position that does not exacerbate pain.

Identifying the occupational trend of lower back pain at the battalion level resulted in proactive measures to improve prolonged sitting posture and helped return Soldiers to duty. For this reason, I recommend that DOD consider revisiting standards for seat design and include a measure that addresses angulation or adjustment of the seat to rest 5 to 15 degrees below the horizontal.

Taking the steps described in this article can do much to reduce the number of complaints of pain by support Soldiers. Teaching them to properly don their OTVs and adjust their vehicle seats will go far in reducing injury and keeping Soldiers on the job.

Lieutenant Sarah D. Thomas, USN, is a physical therapist aboard Naval Hospital Camp Pendleton in California. She is currently the Division Officer of the Physical Therapy Department and the Sports Medicine and Reconditioning Team Clinic at the Marine Corps School of Infantry. She deployed with the Navy Expeditionary Medical Facility to Kuwait in 2007. As the only active duty Navy physical therapist stationed in the region, she supervised care for active duty personnel in five clinics. She also performed various worksite evaluations for the Army in the interest of preventing work-related injury and reducing lost work hours due to medical profile. This article is a summary of two major conclusions drawn from that collaboration.

The author thanks Major Kurt Zacharias, Alfred Rice, Lieutenant Colonel Helen Meelheim, Ben Reese, Mike Buchen, and SKYDEX for their support in the initiatives that led to this article.