Epidemiology and Disease Surveillance Portfolio
Army Public Health Center (Provisional)
Aberdeen Proving Ground, Maryland
In his ancient military treatise "The Art of War," Sun Tzu notes that if you put your army on a forced march at a certain speed, you will lose one-tenth to two-thirds of your troops along the way. While technologies have changed over the past 2,400 years, the effectiveness by which troops can march long distances with their equipment continues to be a critical factor in the success of many military operations.
During dismounted troop foot movement, Soldiers must carry heavy equipment over varying terrains with multiple environmental hazards. Carrying heavy loads leads to more rapid fatigue, greater food and water requirements, awkward body postures, and unaccustomed stress and friction to various body parts. These factors reduce Soldiers’ physical and mental combat performance capabilities and increase the risk of injuries. The impacts can be fatal for individuals and detrimental to unit mission success.
Though its costs are well documented by both scientists and military historians, the ability to effectively and rapidly move troops by foot is an indisputable advantage in many operational circumstances. Therefore, foot march training, or “rucking,” remains an important component of Army readiness training. Foot march training that is too excessive or intense, however, can unnecessarily increase the risk of both acute and overuse injuries. The injuries can cause a few days to weeks or months of limited physical activity or medical treatment and possible permanent disability.
Though training to fight will always be associated with some injury, the Army can train smarter. Various military studies and observations support this concern, such as:
• Foot march training was found to be five times more hazardous in terms of injury rates than regular physical training.
• Foot marching was reported as the second-leading cause (next to running) for training-related injuries in IET trainees and a non-deployed infantry unit.
• Ruck running may increase injury risk, so speeds should not exceed 3-4 mph.
• Performance has been optimized by training programs that include a mix of loaded foot marching (e.g., one session each week to 10 days); non-march upper-body resistance physical training (e.g., two session per week); and aerobic training with intervals (e.g., 2-3 session per week). Programs that do not include adequate non-marching activities to increase overall physical fitness may have higher injury rates.
• Training programs that increase the intensity (load weights) and/or distance (time) too quickly can increase injury risk. A general rule is to not exceed a 10 percent increase in intensity or distance on separate days weekly.
Injuries of concern
Foot marching-related injuries can occur in almost any part of the body (see Figure 1 below
). Most injuries result from the repetitive stresses placed on the body’s skin, bones, muscles and nerves. The vast majority occur in the back and lower-extremities, including the legs, knees, ankles and feet.
Environmental conditions can also contribute to injuries. For example, rough terrain and imbalanced loads can lead to acute sprains or fractures from slips, trips and falls. Heat stroke, heat exhaustion and heat cramps are a concern given the hydration needs of personnel wearing body armor and carrying heavy gear. Cold weather, altitude, insects and animals can also cause injuries.
Severe musculoskeletal injuries — such as ankle fractures or sprains from falls or stress fractures from overuse — can require substantial medical care and result in months of lost duty time or even medical discharge. Stress fractures in the pelvis, which have been found more frequently in female recruits, require especially long rehabilitation. Various injuries to the back and knee pain may become more noticeable over time, reoccur sporadically or possibly result in long-term chronic conditions.
Even minor injuries such as blisters or foot numbness can become severe if not addressed in time. Some injuries, such as ruck sack palsy, a specific shoulder nerve compression condition, are uniquely associated with ruck marching. Other overuse injuries may not be attributed to foot marching activities alone. For example, stress fractures of the hip, leg and foot and knee injuries may be exacerbated by running.
What’s the solution?
Unfortunately, technology alone cannot solve the age-old problem of overloading the foot soldier. In fact, over the last century — despite the weight reduction of some items — technological advances in individual protective equipment, munitions and communication systems have instead contributed to an increase in the average weight of carried loads (see Figure 2 below
). Other “heavy” supplies, especially water, simply cannot be replaced. The loads carried in recent operations in the Middle East have been reported to average more than 100 pounds.
Unit leaders should consider the following suggestions to both optimize performance and minimize injuries:
• Review injury risk factors and possible prevention tactics (see table below
• Encourage Soldiers to modify individual factors within their control.
• Plan and document the unit’s foot march training program purpose, necessary distance(s), equipment and weights, speed(s), terrain and environmental factors, and progression goals and dates for each training session.
• Ensure physical training regimens avoid consecutive days of intense lower extremity training such as distance runs and foot marching.
• Be aware of the unit’s injury rates and the types of injuries experienced to adjust training regimens as needed.
• Consider coordinating with master fitness trainers or physical therapists to establish and plan a training program that is best suited for a specific unit.
Train to fight smart
The Army’s primary investment is in developing and maintaining Soldiers who are physically and mentally ready to fight our wars. Rigorous physical training is a necessary part of this investment, and with it there will be some injuries. However, many injuries are not an acceptable part of “doing business” — nor should they be a way to “weed out the weak.” Unit leaders should assess their foot march training programs and apply prevention measures to help minimize these injuries.
Leaders and Soldiers are encouraged to submit questions or share information that might help address current data gaps on this topic. Submit comments to the Army Public Health Center (Provisional) at firstname.lastname@example.org
. For additional information, visit the APHC Injury Prevention webpage at http://phc.amedd.army.mil/topics/discond/ptsaip/Pages/default.aspx
. Also look for the update to Army doctrine Field Manual 21-18, Foot Marching, pending publication as ATP 3-21.18 later this year.