When the grid fails, only the strong survive, so you'll need to be in the best physical condition of your life. Just start early, because by the time you need this strength and endurance it may already be too late. Here's a look at how you can develop your own boot camp using the workouts military experts use to increase flexibility and improve strength.

The Basics

While fancy weight machines and free weights might look impressive, they won't build the flexibility and strength that come in handy in a gridless world. Some of the best fitness standards are ones you can achieve without expensive equipment. Minimum requirements for the Army PFTs are simple, from ages 17-21, men must be 42 push-ups-strong and women 19. Both should reach the 53 sit-ups requirement, and a 2-mile run should take a man no less than 15 minutes and 54 seconds, and a woman 18 minutes and 54 seconds. Keep in mind that, as age increases, minimum requirements decrease. The best part is you can keep up this regimen anywhere in the world and don't have to worry about being bogged down by equipment.

Track Fitness

Sometimes tracking your progress isn't easy. State-of-the-art mobile devices, like the Apple Watch and the Apple iPhone 7 can monitor your step count, heart rate and even calories burned each workout session. There's even an app that allows you to pick a charity of your choice and, as you run, walk or cycle, a corporate sponsor donates a few cents for every mile you manage. Of course, you can do more than this with your new iPhone and Apple Watch, which are both compatible with medical-grade hardware and software. For instance, the Kardia Mobile smartphone case and the Kardia Band can capture EKG measurements, electrical measurements in your heart, and send the data directly to your doctor.

HIIT Training

HIIT, or High-Intensity Interval Training, is a technique that builds endurance, strength and recovery time. Hiit focuses on all-out, one hundred percent bursts of activities for a short time. These bursts are followed by short, and sometimes, active recovery sessions. Many people use HIIT techniques to increase their metabolism. The metabolic boost you get from a HIIT workout can raise your metabolism for 48 hours. Another reason HIIT routines are so popular is they're quick. Giving one hundred percent of your physical effort, even for a short time, wears you out quickly — which is why most HIIT workouts are 30 minutes or less. Lastly, no equipment is needed for a HIIT workout. HIIT promotes workouts that use body weight, which promotes optimal muscle gain and fat loss.

So how do you get started with your first HIIT workout? It's easy. Start off slow — or at least follow a routine that won't cause you to pull a muscle or strain a tendon. For instance, your first workout might consist of a 10-minute routine, 20 seconds of exercise, 10 seconds of recovery. Start with 20 seconds of cross-punch jabs. Make sure you stay on the balls of your feet and pivot with each jab, which will turn your body and work your abs. After 20 seconds, take 10, then transition into jumping jacks for 20 seconds. Your last set will be 20 seconds of sumo squats. Once you've done each exercise, begin again from the start. Repeat until ten minutes is up. While this is just a sample workout, there are far more you can explore that will work other parts of your body to get you in peak physical condition when you need it most.