It may be Canada's best-kept exercise secret: an 11-minute, no-equipment workout program designed to keep pilots and other Air Force members in top shape even when they were posted to remote areas without gym facilities.
The program, called 5BX for "Five Basic Exercises", was invented in the 1950s but has aged fairly well. (When Runner's World writer Alex Hutchinson started looking into the program, he found out his uncle had been doing it for almost 50 years.) The old-school sit-ups in the program should probably be replaced with crunches or other ab exercises, but otherwise it's still solid.
There are six levels, or charts, with progressively harder variations of each exercise. Chart 6 requires clapping push-ups, for example, where Chart 1 just had knee pushups. For each chart, there's a corresponding set of benchmarks according to how many reps you can do. When you hit A+ level on a given chart, it's time to move up to the next one.
You can download the original booklet here, or check out the full article at Runner's World for more background on the program.
The Fighter Pilot Fitness Program [Runner's World]