Can you run 1 mile without stopping?
This is a pretty standard test for cardiovascular endurance and for good reason I believe. If you ever find yourself in a situation where you need to find help or get assistance for an injured buddy, and you have no mode of transportation, you have to hit the pavement. If you start bookin' it and die out after the first quarter mile then the person you are trying to help is going to suffer. I chose the mile for testing because in today's world you can usually find something or someone within in a mile (obviously there are exceptions). Also, minutes count during an emergency so just being able to finish a mile without stopping doesn't really mean much. To really count yourself as being functional in this situation I would rate performance as follows:
Under 6:00 = Excellent
Under 8:00 = Fair
Over 10:00 = Things aren't looking good for your buddy.
Can you ascend and descend a structure that is taller than you?
This test gauges your ability to overcome an obstacle with your own body. Imagine that your life is in danger and you have to overcome an 8 to 10 foot obstacle or you will die. You could be fleeing captures or getting engulfed by flames, but either way you need to get your ass up and over something. To count yourself functional you should be able to ascend and descend an obstacle or structure that is taller than your standing reach (it should go without saying that obstacles with handles and convenient holds don't count).
Can you push a vehicle a quarter mile?
This situation might not have to deal with life or death but still may come in handy. I see people all the time in their broken down vehicles sitting in the middle of the road. Not only is that pretty embarrassing but it causes a huge back up in traffic. I always wonder why they just don't push their car a block or two and get it out of the way for everyone else, but I forget that some people are physically unable to do that. Being able to push a car is not only a good skill to have for life but also for the ladies. If you are a guy, nothing says manly more than pushing a damsel in distress in her broken down car to the nearest service station.
Can you carry a person of similar size 100 meters?
This is your basic "carry a person from a burning building" scenario. You don't have time to wait for the fire fighters and you are staring at an unconscious person about to be engulfed by flames. Your only choice is to pick up the person and carry them out to save their life. Now I realize that testing for this one might be a little awkward but grab a friend and see what you are made up. Throw them over your shoulder like a sack of potatoes and see how far you can make it. A good training tool you can also use is a sand bag. It is uneven dead weight, much like a person, and you can fill a bag with sand anywhere from 25lbs to over 150lbs. To be considered functional you should be able to carry a person or object of your own bodyweight for 100 meters.
Can you swim 100 meters without stopping?
Swimming is definitely a skill that could save your life. You see news stories all the time of people who have drowned in a lake, river, or ocean because they got separated from the boat or swept away in a current. I remember back in college I took a swimming class and some of the other students were seasoned, college athletes. Strong and powerful baseball and football players would cramp up and have to grab the side of the pool during a 50 meter swim. Power and strength won't help you when you are fighting a current and need to swim to the nearest shore. It is a relatively simple skill but one that needs to be trained on at least a seasonal basis. Again, intensity matters so just doing a doggie paddle for 100 meters won't cut it. To be functional you should be able to do a continuous front crawl for 100 meters*. I chose 100 meters because in most cases that is far enough to reach safety. A good time to shoot for is less than 2:00.
(*For most pools 100 meters is around 4 pool lengths.)
So there are 5 challenges to test your current level of functional fitness. You can use these tests to identify deficits in your current abilities and then perform them periodically to measure progress and maintain abilities. In today's world we rely so much on technology and modern conveniences, and in most cases those things will help keep you safe. But when technology fails you want to be ready with a strong mind, body, and will. It just might save your life!