NATICK, Mass. (Oct. 9, 2014) -- Body armor has saved countless lives in Iraq and Afghanistan, but an Improved Outer Tactical Vest, or IOTV, that doesn't fit properly can actually hinder a Soldier's performance in combat.

That's why members of the Anthropology and Human Factors Teams at the Natick Soldier Research, Development and Engineering Center are conducting a range-of-motion and encumbered anthropometry study to better understand the link between fit and performance with the IOTV Gen III.

"We have this belief that if the fit of the body armor is really good, then the performance is going to be maximized," said Dr. Hyeg joo Choi, the principal investigator for the study. "So the question is, how can we quantify a good fit so that Soldiers' performance is maximized?"

To help answer that question, Choi and her fellow researchers collected measurements from 23 Soldiers at Natick, including 21 males and two females.

"We look at the body size first," Choi said. "And then everybody is tested in approximately three different (vest) sizes. Out of these sizes, we basically look at what the best performance size would be."

According to Human Factors project lead Blake Mitchell, after the IOTV was introduced in 2007, fit was identified as an issue for some wearers. Mitchell said this was a particular problem for female Soldiers.

In 2009, along with a team of human factors subject-matter experts, Mitchell and anthropologist Dr. Todd Garlie went to the field and measured 139 female Soldiers. Their results contributed to the 2012 issuance of IOTVs designed specifically for women.

Data collection began in June for the current two-year study, which used the vest portion only of the Gen III IOTVs.

"There wasn't any mission-essential gear included with this study, which might impact performance a little bit more," Garlie said.

Choi's early data suggest the current legacy size chart should be updated to reflect body size changes, which will be consistent with what Natick's ANSUR II anthropometric survey revealed in 2012 -- today's Soldiers are bigger than they were 20 years ago. The key measurement for IOTV fit, said Choi, is chest circumference.

"There are some people who are not really affected by the body armor size," said Choi, "and then there are some people who didn't really perform that well in any of the sizes."

Mitchell said she hopes that Choi's work will provide not just updated sizing information for the IOTV Gen III, but design guidelines going forward.

"So that it's not just this body armor system," said Mitchell, "but it can help drive future body armor system designs."

The study may also support the development of other protective clothing and equipment systems.

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The Natick Soldier Research, Development and Engineering Center is part of the U.S. Army Research, Development and Engineering Command, which has the mission to develop technology and engineering solutions for America's Soldiers.

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