The Prediction and Evaluation of Strength and Fatigue to Prevent Warfighter Musculoskeletal Injuries
Abstract
Those whose work often involves heavy physical labor, such as nurses, construction workers, and Soldiers, often experience a decline in the health of their muscles over time due to frequent overuse and overexertion. This is particularly true for Soldiers who often must carry a load three times heavier or more than what is recommended to transport armor, power, ammunition, and supplies. Rather than waiting for injury and needing physical therapy, there is significant interest in developing methods of preventing muscle injury and poor muscle health before pain and poor functioning become an issue. One solution that is being developed is an exosuit, or a wearable device that senses the wearer and their movement and helps them move or do work. The concept of an exosuit for the military has been around since the 1960s, when the first device to improve Soldier strength was developed. This early exosuit, and other exosuits and exoskeletons that have been developed since then, however, have faced significant challenges as they are big, heavy, and require a lot of power. An even bigger problem for past and current exosuits is the way they attempt to help the wearer. A common claim of an exosuit is that it allows the wearer to lift a much heavier burden than they could have otherwise or walk farther rather than they normally would. This is done, in theory, by adding strength to the muscles that may need it (such as in the arms, back, thighs, or calves). Unfortunately, what happens instead is that the wearer must often struggle with the exosuit to make simple movements because the exosuit applies too much or too little strength in the wrong place at the wrong time. This problem means that it makes the wearer of the exosuit more tired and wears out the muscles faster than with no exosuit. One reason why current exosuits do not work is that they cannot change how much strength they give to the wearer based on what they actually need. For example, if a Soldier is carrying a heavy pack through a hot desert, their muscles may be expected to act differently than if they were walking through a snowy mountain. The Soldier’s muscles may also be expected to act differently right after a long rest as compared to right after strenuous exercise. In this proposal, we discuss developing an exosuit that can use this information, specifically information about the person (their height, age, weight, etc.), the person’s environment (temperature and humidity), and what work the person has done recently (rested vs. tired), to give the right amount of strength at the right time in the right place. This will be done not only by designing an exosuit that can measure and sense these things, but also by developing a computer model that can predict what strength is needed based on those same three factors. Not only is it new to combine all three of these types of factors to predict muscle strength, but this work proposes to use the exosuit and computer model as a tool to diagnose muscle health. The Soldier will use the exosuit to measure their “normal” muscle strength when they are healthy. This will be tracked over time, and if the measured muscle strength decreases beyond what one would expect from heat or being tired, a doctor can detect that the muscles are becoming unhealthy. When this decline in muscle health is measured, a doctor can prescribe rest, exercises, or medicine as needed in order to aid the muscles before a serious injury occurs. Also, doctors can use the exosuit to measure when a person who was injured is healthy again by comparing their current muscle strength to what it was when they were healthy. This new exosuit and computer model will enable Soldiers to stay healthier by catching muscle health problems early and making sure they are healthy enough after injury to resume their duties. To develop this exosuit and computer model, subjects who are 18 to 30 years old will be asked to participate in a working tasks tri
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 10, 2021
- Source ID
- W81XWH2010030
Entities
People
- Amanda Koh
Organizations
- United States Army
- University of Alabama