You don't need to join the Army to enjoy the many benefits of doing a proper push up. A basic push up does not require any equipment other than your own body weight and your arms. It can be done anywhere there is a firm surface, and it helps strengthen the chest and arm muscles.
You're probably familiar with the advice to avoid doing the same exercises all the time. You need to "confuse" the muscle to keep building it. So doing the standard push-up exercise with your legs straight or knees bent on the floor, while certainly beneficial, will start to lose effectiveness over time if you don't add in new challenges. To get more out of your push-ups, try mixing up your routine with these simple tweaks:
The Push Up
Different Variations, using your own body weight, in home exercise :)
- One Arm