There are many reasons to praise the traditional push-up, an all-purpose exercise that activates muscle groups from the back of the neck to the base of the spine. Foremost among push-ups' many virtues is its adaptability. By adjusting it in any of a number of ways, you can ramp up its intensity and accentuate certain muscles.
Determining which is the best, though, depends on your own particular level of fitness. If you really want to work the shoulders, get into inverted push-ups, starting with the Pike Push-Up and working your up to the king of all shoulder-building push-ups, the hand-stand push-up.
As you progress toward being totally upside-down, you'll be increasing the amount of your own body weight that you'll be pressing. You'll also be transferring more of the load from your arms to your shoulders. In ascending order of difficulty, here are the candidates for best shoulder push-ups.
The Pike Push-Up
This is the gateway push-up to the handstand push-up. A study in the Journal of Physical Science Therapy in 2014 found that push-ups done with the torso flexed to a 30 degree angle — such as with the Pike — significantly activated the muscles along the clavicle, or collar bone, which serves as a strut between the shoulder blade and the breast bone.
Start in plank position as if you're going to do a regular push-up with your arms straight and your hands shoulder-width apart on the floor.
Now hike up your hips up high so that your body is in an exaggerated downward-facing dog position or an upside-down V, with your ankles flexed so that you're on the balls of your feet, and your torso at a deep incline. Keep your legs and arms straight.
Now, bending your elbows, lower your torso until your crown is almost touching the floor. Pause, then press yourself back into the starting position with your arms straight.
You can jack the Pike up a notch by elevating your feet on a bench, stairs or other surface. The higher your feet, the more downward thrust your shoulders have to bear.
The Handstand Push-Up
According to the American Council on Exercise, the dumbbell shoulder press is the most effective exercise for building your shoulders. What's that got to do with push-ups? Do a handstand push-up, and you're pretty much replicating the dumbbell shoulder press. Because your body is upside down, you're using your arms to press the weight of your entire body — but you're also transferring more of the load off the upper arms and into the shoulders. Three sets of these babies a day, and you'll be as wide Texas in no time.
Note that this exercise requires a certain base level of shoulder strength, so prior training is necessary before it's attempted.
Start by facing a wall and doing a forward fold, placing your hands on the ground at shoulder width.
Use your legs to spring your torso upward against the wall, supporting yourself with your arms fully extending and maintaining a straight (though upside-down) posture. A spotter can be helpful the first several times you do this.
Now bend your arms, lowering yourself vertically to the floor until your head touches. Press back upward, using your arms to lift your feet toward the ceiling. Avoid locking your elbows because it takes tension away from the muscles.