Push ups should be a staple in everyone's training. This bodyweight movement creates a safer environment for your shoulders than lifting barbells – especially if you've got muscle imbalances – and they work the core better than most bench press variations. More than that, they're convenient and can be done anywhere.

First, know how to do a standard push-up with good form: Be sure to be in a start position with arms fully extended, and hands approximately shoulder width apart. Squeeze your shoulder blades in towards one another, and keep the hips from falling to the floor. There should be a straight line from your shoulders to your heels. Keep the abs and glutes tight. From there, bend at the elbows until your chest lightly touches the ground, and return to full extension. Remember not to look upwards. 

Once you have this down, try one of these 10 variation to spice things up.

1. Elbows In: Keep the elbows nice and snug to the body as you go through the movement. Not only will you save your shoulders from unwanted stress, but you'll hit the triceps more effectively too.

2. Elbows Out: Alternatively, if you're looking for chest and shoulder emphasis, flare the elbows – as long as the shoulder joint can handle it. It's better to practice this method with push ups than adding weight to the position in the bench press.

3. Hands Wide: To hit the outside of the chest, and also to shorten your range of motion, bring the hands 6-12 inches wider on each side. It's a stronger position and can help you crack out more reps.

4. Hands Together: Just like the elbows-in method, this is your ticket to triceps stimulation, but the close hand position will add some range of motion, and also make the abs work harder to stabilize due to the narrow base of support.

5. Staggered Hands: Staggering the hands so one is up high, and the other is by your side is a good way to emphasize one arm at a time to bear most of the load. Try different hand staggers too. One narrow/one wide, one high/one low, and both narrow while high/low.

6. Chest to Floor: If you really want to get stronger at push ups, treat them like deadlifts. Come to a dead stop on the floor and push yourself off the ground with good form using zero momentum. A two-second pause on the ground will ensure this happens, and train your starting strength in the process.

7. Scapula Push-Ups: This is a technical one. Assume your classic push-up plank position, then let the shoulder blades move as far towards each other and as far away from each other as possible. Keep straight elbows the whole time. When you master this, you'll begin to feel your serratus muscles (beside your ribcage) firing.

8. Suspended Push-Ups: Use the TRX (or a pair of gymnastic rings) to do your push-ups for stability training. It asks much more of the rotator cuff to stabilize the hands and arms, since they're no longer on solid ground. You've also got a chance to add a few vital inches of ROM by going all the way down past hand level.

9. Superman Push-Ups: Find a wall and assume a handstand position. Keep the feet against the wall as a guide, and lower the body until the head brushes the floor. If that's too hard, find a bench and mount the feet while the hands are still on the floor. Pike at the midsection (so your butt's up high), and perform the exercise.

10. Plyo Push-Ups: Adding plyometrics to a movement makes it more explosive in nature, and trains your fast twitch muscle fibers. The rules are simple: Push up strongly enough for your hands to leave the ground. Keep the reps relatively low here. As soon as the reps become slow, cut them off.