The act of going hard or extreme on any aspect of life. Such as training extra hard for a sport, trying your best at something physical, improvising or taking large risks, giving something all you got, and going over the top. The term is influence by the Vietnam War when soldiers had to fight against terrible odds and endure an extreme fighting condition.
"Hey man, you totally went 'Nam style on that 800m run, you beat your time by 18 seconds!"
"When I went hiking in West Virginia and got lost I had to go 'Nam style. I didn't eat for three days and had to hike 4 miles with a broken leg.."