Pushups are to fitness equipment as Old Faithful is to Disneyland. Just like those who prefer oversized mice and animatronic yodelers to the quiet understated beauty of nature, the pushup has given way to fancy gizmos and gadgets that offer promises of greater gains. While a pushup may not provide the same external resistance offered by gigantic dumbbells (unless your workout buddy sits on your back), when done properly, it is probably one of the most functional and effective exercises for improving overall strength, stability, endurance and more. A staple of military training, its convenience is unparalleled in that it can be performed pretty much anywhere, and with some variations can give you a kick-ass, full-body workout without the use of cumbersome external resistance. Implement the following exercises into your routine for variety as well as to improve strength and endurance for the whole body (make sure you are cleared for exercise before attempting any movements).

You may not consider the traditional pushup much of a challenge. Most often this is due to wide arm-positioning, which focuses a great deal of effort on the overused front of the shoulder. This also reduces contraction of the chest muscles. In order to emphasize the chest (and triceps), start with the hands directly beneath the shoulders. Suck the belly button into the spine, bring the head back in line with the body and actively contract your glutes (squeeze your cheeks). Imagine yourself as rigid as a 2 x 4 and focus on holding this alignment throughout the entire motion. Slowly lower your body, making sure to keep the elbows tucked into your sides at all times (instead of jutting out away from the body). Stop when the elbows are at 90 degrees. Hold for two or three seconds and then slowly push away from the ground until you reach the start position.

Some helpful tips: Keep the head and belly from dipping toward the ground as your body lowers. Resist the urge to race through your repetitions; the longer your muscles contract, the stronger they become.

For those of you who experience difficulty with the traditional pushup, an effective alternative is to perform the exercise with bent knees. This is an excellent way to perfect your form while you build strength. After a few weeks of bent-knee pushups, you’ll be ready to take on the traditional.

This is an excellent exercise for those who spend a great deal of time sitting during the day. It will help strengthen the glutes and other muscles that extend the hips and improve flexibility of the often overly tight hip flexors (muscles responsible for lifting the leg or moving it forward). This exercise is performed just like the traditional, except that you lift one foot off the ground while being careful to keep the lower back from arching. Perform half of your repetitions with the left leg lifted and finish off while extending the right, or alternate leg lifts with each repetition.

Changing the angle of the pushup is a great way to increase intensity. Find yourself a bench, stability ball or other object to rest your feet on while you perform the movement; the higher the platform, the more difficult the exercise.

Another military-style pushup, the dive bomber is often utilized by the Navy Seals (though you probably won’t be performing the exercise while being pummeled by crashing waves) and helps to shape the upper body, improve shoulder stability and range of motion, and increase flexibility in the lower back, hamstrings and hip flexors. Start with the body in an “A” shape with the hips reaching toward the sky and the hands slightly in front of the body (for you yogis, this is similar to a down dog). Lower the shoulders, followed by the chest and the rest of your body, and then slowly push the upper body away from the ground. Hold and then reverse the motion.

You’ll need a good bit of space to move forward for this killer exercise. Start in the traditional pushup position and then reach the right arm and left leg forward so that the legs and arms are staggered. Perform a pushup and then move the left arm and right leg forward and do another pushup. You will be in continuous forward motion during this exercise. Once you master the forward motion, try the crawler while moving backward.

This is just a small sample of the various methods for increasing the intensity of the traditional pushup. Make sure to keep tip-top form and you’ll be on your way to a stronger, more functional body.