By Dakota Grossman, writer, and Dr Steven King, managing member, Kingetics
Kingetics, a small veteran owned startup company has developed and tested new technology that has shown significant improvements in protecting our soldiers as well as improving the gait of mechanical walking systems.
Load carriage and high impact forces on the lower limbs are often cited as leading causes of musculoskeletal injuries. Injury rates during military training range from 1 per cent to 16 per cent, and up to 30 per cent in elite infantry units.
Data from Podiatry Arena shows that there are about 32,000 broken bones per year during military combat, costing the US Department of Defense an estimated $240,000,000 in medical expenses.
Such injuries include stress syndrome, muscle and ankle sprains, knee pain, and metatarsal stress fractures. The most common was tibial/fibular at 40 per cent.
Service members under 20 years of age and women are shown to be at a higher risk for lower extremity fractures.
In another study, 5.7 per cent of male and 19.1 per cent of female cadets had at least one stress fracture, most being within three months of entry to the United States Military Academy.
The Kingetics Mechanical Insole System Lever, an orthotic design that incorporates a lever and spring plate, is an innovative solution that decreases the risk of injuries mentioned by reducing impact, and increasing energy storage and return, according to SBIR contract A11-109 “Advanced Composite Insoles for the Reduction of Stress Fractures” by the US Department of Defense Army Medical Research and Materials Command.
“A major challenge was finding an innovative solution that will decrease the risk of musculoskeletal overuse; however, the composite materials that make up the Kingetics orthotic, such as carbon fiber, aramid ballistic materials and Kevlar, create a lightweight, puncture resistant, and protective footwear for soldiers in combat and during training,” said Dr Steven King, inventor of the innovation.
The Mechanical Insole System Lever has been worn while enduring multiple terrains and distances to ensure longevity and stability, such as the Xterra Championship and the Maui Marathon.
A 2017 Government Accountability Office report identified Marine loads to be an average of 117 pounds, and Army loads an average of 119 pounds. Typical combat boots weigh between two to three pounds.
However, Kingetics weigh around one to two pounds, which is up to 30-50 per cent lighter and will help to mitigate the heavy load. As the foot approaches the ground, the spring orthotic absorbs the impact force of the ground (F) by bending. The tension in the bent spring is stored as potential energy.
As the heel is raised, the orthotic pushes against the ground reactive force (G) and the moment (M) helps to restore the foot to a horizontal position (F = (h3 w E d)/4L3).
This formula also demonstrates how the mechanics can lead to an decrease in VO2 max. Mechanical testing has demonstrated that blown foam midsole materials provide less energy return upon impact than the Kingetics system.
Carbon fiber combined with mechanical levers creates a responsive plate for the average walker and runner, as well as a demonstrated a 3 to 10 times more puncture and blast resistance for soldiers and officers.
Ongoing product testing showed a 10 per cent increase in subjective comfort ratings when compared to traditional combat boots. Early preliminary testing conducted at the University of Texas showed a 5-6 per cent reduction of force upon vertical ground impact.
Kingetics demonstrated that lever insoles has the potential to reduce the risk of stress fractures and strains caused by repeated, heavily loaded impacts.
This research was accepted for an oral presentation at the International Society of Biomechanics this past summer in Calgary. Researchers at Lehigh University studied a similar reaction using accelerometer testing and analysis.
The Senior Design Capstone team measured vibration forces on the tibia-shins while subjects wore the orthotics while jogging or on a treadmill.
Data showed a reduction of shock upon impact by 10-13 per cent with regards to overuse injuries of the foot, 10-20 per cent for plantar fasciitis, 5 per cent for metatarsal stress fractures and 4 per cent for tibial stress syndrome due to insert/orthotic use.
The same university later conducted a study with eight test subjects where they analyzed the difference in walking and running on a flat surface versus an inclined surface while using the Kingetics orthotic device versus without them.
Backed by t-tests, the overall average maximum acceleration of shock events (3.5G of force compared to 5G of force) was lower among 10 subjects running with Kingetics on a flat surface. For inclined surfaces, the average maximum acceleration of shock was lower for about 60 per cent percent of subjects.
The orthotic provides significant personal protection from puncture and did not catch fire during vertical and horizontal flame testing from prior SBIR A11-109 Deptartment of Defense Army Medical Research and Materials Command at the CAPE Lab at the South Dakota School of Mines and Technology.
This demonstrates that the composite materials increase puncture-blast, heat and fire resistance to protect lower extremities and other vulnerable under protected bodily areas.
Mechatronics study
North Dakota State University conducted mechatronic (mechanical electronic) studies by incorporating electric piezo electronic wafers and strain gage sensors within the composite orthotic system.
This helped to collect further biometric data. This approach can assist quantifying how much impact and impulse the foot and lower body absorbs and returns during the gait cycle “heel strike to toe off”.
Vertical force and limb velocity sensors were placed on the soles of the Kingestics orthotic, and then cross analyzed with data collected from reactive forces from a standard blown foam shoe system.
The foam shoe exerted no force into the ground after heel strike while Kingestics did, which would significantly reduce the amount of energy used by military personnel, for example, as the orthotic lever system propels the foot forward, reducing shock and improving efficiency.
A t-test was conducted to test the significance between the data sets. Further testing and analysis is expected to continue to develop the insole system.
An E-1 recruit makes about $20,000 a year. Stress fractures take 2-3 months to heal, which costs around $5,000 per incident for a soldier who cannot train nor fight. Medical visits average $200 per visit, and require approximately five visits.
Potential X-rays and CT scans are $1,000 each. An additional $500 may be added to expenses for the use of casts, crutches or orthopedic boots. So, 32,000 broken bones x $7,500 = $240,000,000.
Kingetics was a finalist for the innovation challenge at the inaugural WearRAcon conference. Kingetics was awarded the 2015 Most Creative Application Award from the American Composites Manufactures Association.
Kingetics has completed phase 1 SBIR testing for the US Department of Defense and Army Medical Research and Materials Command for SBIR A11-109 “Advanced Composite Insoles for the Reduction of Stress Fractures.”
Dr King, a prior army podiatrist, has been the co-inventor and co-principle investigator of this internationally patented technology.
He is a committee voting member for ASTM F48 Exoskeleton and Exosuits, E54 Homeland Security Applications and Personal Protective Equipment and F13 Pedestrian and Walkway Safety and Footwear Standards.
Dr King has also served on the NIST-DoD-ASTM Jungle Boot Working Group to improve soldier security and ability.
