Loaded Research Question
Helmet, uniform, boots, armor, weapon, ammo, food, canteens, compass, first aid kit—everything a soldier wears and carries (their “load”) can add up to more than 68 pounds. In a combat mission, that weight can skyrocket to as much as 120 pounds. Carrying a heavy load while walking, marching, running, or even fighting is essential for every soldier, regardless of gender.
“A soldier can’t say, ‘I can’t carry this much water because it weighs too much,’” says Kari Loverro (’19), a doctoral candidate who is studying the biomechanics of how soldiers carry heavy loads. “You have to carry what you need for the mission.” All that weight is associated with high rates of stress fractures and other musculoskeletal injuries to soldiers’ hips, legs, feet, and ankles. For female soldiers, the risk of stress fractures to their lower extremities is 2 to 10 times greater than for their male counterparts. Loverro wants to know why.
Her study comes at an important time for the military. While increasing numbers of women are serving in combat roles—the Department of Defense (DOD) lifted its ban on women in combat in 2013—there has been relatively little research on how female soldiers carry heavy loads. In general, women are shorter, and weigh less, than men. So while they are required to carry the same load as men, their relative load is greater.
To figure out if men and women carry their load differently, Loverro is modeling pressure between the bones of the hip during walking. In Sargent’s Human Adaptation Lab, she outfits a group of volunteers with weighted vests that represent the loads of up to 60 pounds that soldiers may have to carry on their torsos during foot marches and combat missions. Those volunteers march on a treadmill at varying rates of speed while Loverro uses high-tech sensors, reflective markers, motion cameras, and computers to track their every movement.
“Our soldiers put themselves at risk in ways we cannot control. We should at least control the ways we can reduce the risk of musculoskeletal injury.”
In her ongoing study, Loverro is investigating whether soldiers adapt to a heavier load on their torsos by leaning forward, or slowing down, or taking shorter steps, and whether the load makes them more likely to fall. She hopes to learn how men and women change the way they walk when carrying heavy loads at different speeds, and how these adaptations may cause stress and even harm to their bones. Loverro, who is pursuing a doctorate in rehabilitation sciences, hopes her study will lead to interventions that can prevent injuries to soldiers, men as well as women.
“Our soldiers put themselves at risk in ways we cannot control,” says Loverro’s mentor Cara Lewis, an associate professor of physical therapy who directs the Human Adaptation Laboratory and teaches in the PhD program in Rehabilitation Sciences. “We should at least control the ways we can reduce the risk of musculoskeletal injury in training and when carrying a load.”
Loverro has a personal investment in her research. Her father is a retired Air Force colonel and was deputy assistant secretary of space policy under President Barack Obama. Her mother, a retired Air Force lieutenant colonel, was a professor of aerospace studies in BU’s Reserve Officer Training Corps program in the 1980s.
“I am honored to come from a military family,” says Loverro, who spent four years as a postgraduate research fellow on the biomechanics team at the US Army Natick Soldier Research, Development and Engineering Center (NSRDEC) in Natick, Mass. “Even though I do not wear the uniform, I feel that this is my way of giving back to the men and women who put their lives on the line to protect us. I want to make sure that every soldier has the best possible chance of staying safe in the field while performing their mission.”
A Soldier’s Recommended Load
M4 assault rifle
first aid kit
1-qt canteens of water
(2 per soldier)
grenades (2 per soldier)
From the US Army Field Manual, 1990
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