Security, increased by armor, can reduce mobility. Since WWII, the U.S. Army has worked to develop body armor that balances these two competing factors.
Spartan Armor Systems: 3 Factors to Consider Before Buying Body
This Vest May Save Your Life!: U.S. Army Body Armor from World
Nanoscale experiments give researchers optimism for stronger
Air Warrior soft body armor 1990's? - BODY ARMOR - U.S. Militaria Forum
Body Armor Used Throughout American Wars - Premier Body Armor
What body armor do US Army soldiers use? - Ace Link Armor
Air Warrior soft body armor 1990's? - BODY ARMOR - U.S. Militaria Forum
Body armor - Wikipedia
Buying a Bulletproof Vest? Here's How To Find The Best One
Clothes Militaire Combat Body Armor Nij IV Full Protection Cp/Mc/a
Best Body Armor: The Ultimate Buyer's Guide