NATICK, Mass. (Apr. 3, 2020) -- Army researchers are developing the Load Carriage Decision Aid, a software mission planning tool that estimates how much energy Soldiers are burning when marching with heavy equipment over different terrains.The U.S. Army Research Institute of Environmental Medicine has been developing the LCDA from years of metabolic cost and physiological data. The current prototype, which one can use on a personal computer, translates complicated walking equations into a simple user interface with inputs for information about the route, clothing worn, rucksack weight and weather conditions.Commanders and mission planners will be able to use the LCDA to predict Soldiers’ energy expenditure and fatigue levels during a wide variety of Multi-Domain Operation scenarios, such as dismounted maneuvers.Dr. David Looney, a research physiologist from USARIEM’s Biophysics and Biomedical Modeling Division, is leading a research effort to further improve the LCDA’s accuracy. His team is developing new algorithms to better estimate Soldiers’ energy and fatigue levels while carrying contemporary military equipment.“Our goal is to make further improvements to these algorithms, so they apply to modern Soldiers carrying modern equipment,” Looney said. “We found that the existing equations underestimated how many calories Soldiers were burning in the field. We are collecting experimental data from U.S. Army Soldiers to improve the accuracy of the algorithms.”Dismounted movements are a necessary burden in MDOs. Often everything a Soldier needs to fight and survive in diverse battle spaces needs to be stored in their rucksack. They regularly carry weighty loads for long distances and over complex terrain, and they work even harder when walking up or downhill or on various surfaces.When Looney broke down the types of items Soldiers typically carry, it gave a whole new meaning to the expression “carrying your weight.” He explained that critical items for engaging enemy forces, including firearms, grenades and communication devices, make up approximately 30 percent of a Soldier’s body mass or more. Non-combat related, mission-essential items—like extra clothing, rations, hydration packs, medical kits and items for shelter—can add another 15 percent. Looney said that Soldiers might also carry a sustainment load when ground and air transportation resources are unavailable. In these emergencies, the total load can weigh anywhere from 100 to 125 pounds.“Soldiers’ postures and walking mechanics are all very abnormal when marching with heavy packs,” Looney said. “They get fatigued much sooner, and they march much slower for shorter distances. The more weight you are adding to the pack, the worse it gets.“Oftentimes, it is challenging to have Soldiers carry less weight since most of everything they carry is essential for their mission. However, the LCDA can serve as a mission planning tool for commanders to help them visualize Soldiers’ energy expenditure. Leaders can make adjustments to the mission, ensuring that their Soldiers are healthy and ready to fight and win.”Since last winter, USARIEM’s exercise laboratory has been abuzz with researchers collecting data. The team has been working to determine how much energy study volunteers burn while standing and walking with different amounts of weight.Each volunteer begins the study by standing and walking on a treadmill with no pack. As the data collection continues, the volunteers perform the same tests with a rucksack loaded with 22 percent of their body weight. The volunteers complete subsequent study trials by marching with 44 and 66 percent of their body weight.As study volunteers complete each exercise test, researchers measure how fast the volunteers can move while walking and how long they can sustain their marching pace. They also administer questionnaires to record the volunteers’ perceived level of fatigue and exertion. The researchers also collect real-time data, such as respiration, body temperature and heart rate, with the help of sophisticated physiological monitoring equipment.The team is currently halfway through with their data collection. Looney credits this success not only to his team of specialized USARIEM researchers, but also to the other generations of researchers who make up his team. These people include veteran USARIEM researchers who have been studying load carriage since the 1970’s. The team is also composed of interns from Merrimack College in North Andover, Massachusetts, and USARIEM’s Oak Ridge Institute of Science and Education program.“We are drawing from the work of the great USARIEM researchers of our past, such as Pandolf, Givoni, Goldman and Santee,” Looney said. “However, we are also drawing upon the diverse assets of a multi-generational research team. Our partnership with Merrimack College has been especially rewarding. We get extra hands, the students get hands-on experience and both institutions gain from partnering.”According to Looney, all of these data will be used to develop new models for Soldiers during load carriage with the most modern equipment, such as the MOLLE 4000, a recently developed rucksack that is on its way into the hands of every Soldier.While these models could be used by themselves, the research team is developing a version that could be incorporated into other physiological monitoring software and even into Soldier and squad virtual training environments. He also believes the LCDA could be a helpful planning tool for hikers and backpackers.“Understanding load carriage creates a domino effect in improving medical readiness,” Looney said. “The LCDA not only tracks how hard Soldiers are working, but also how many calories Soldiers are burning and how hot they are getting. You can prevent your Soldiers from being overworked, while also preventing other problems, such as undernutrition and heat illness from occurring in the first place, thus enhancing Soldiers’ effectiveness in all environments.”