The Misunderstood Pushup
When you are thinking of what exercise you can do right now to get your heart rate up and get the blood flowing, what comes to mind? What exercise do people aspire to be able to do more of in a single attempt? What is often used to "test" upper body muscular endurance? You guessed it: pushups!
"Why can't I do 1 pushup?" How many times have we heard or muttered this exact phrase? Initially, too much focus is spent on developing arm strength during a pushup, but we need to begin by looking elsewhere. Think about physics and the law of gravity. Gravity pulls EVERYTHING towards the ground. If in a pushup position, we need to focus on more than just the arms: like the abs, hips and legs. If these other structures are not engaged and carrying their own weight, then the arms are forced to carry the excess burden of the weight of those areas as well. As a result, one may have strong arms, even proportionally strong arms for their body size, but still be unable to perform a proper pushup due to a disproportionate amount of weight needing to be lifted by the arms in order to complete the pushup.
See the picture? The male in the foreground is performing what we will now refer to as "arm pushups." Luckily he does not have too much lower body mass, so the pull on his torso and legs is not too great. The low back curve is excessive and indicates that his "core" is not engaged. To engage the muscles of the core, one needs to perform the following steps: (1) Push out firmly through heels, (2) flex quads and straighten knees, (3) squeeze glutes together and (4) tighten abs as if preparing to take a punch to the stomach. By doing this, you will engage the larger muscle groups in your body and require them to "pull their own weight," thereby allowing your arms to push off the ground with their assistance.
Upper Body barriers
Do not underestimate the importance of upper body strength in the pushup. A minimal amount of strength is mandatory and self-awareness is also important in order to know where exactly you may have an imbalance. Commonly overdeveloped areas are the bicep and chest muscles. The areas which help to balance out upper body strength in this movement include the triceps, shoulders and lats and their supporting musculature. The triceps are vital in elbow extension while shoulder strength is critical to assist the chest in moving your arms away from your body. The lats and surrounding muscles are essential to stabilize the shoulder blades and act as the main connection of the upper extremities to the "core" and thereby leg muscles. Without all of these areas of the upper body working together, your pushups will not be as efficient as you may want them to be.
Lower Body barriers
The lower body also plays an integral role in the successful completion of your pushups. Now that your upper body is keyed in, it's important to ensure your legs and hips are assisting as much as possible. For the legs, cueing the heels to push back against an imaginary wall is helpful to engage the quads and straighten the knees. Once that is complete, squeeze the two sides of your glutes together as hard as you can and keep your hips fully extended, or straight. By engaging the legs and glutes, you will notice your pushups seem easier because the arms no longer need to support the weight of your lower body and hips.
Core "linkage" barriers
While upper body strength and lower body muscle recruitment are both important segments of a complete pushup, they cannot be truly effective without the use of the core to "link" them together. Since it has many definitions, I will summarize the components here. The upper extremity stabilizers, midsection and hips need to engage to varying intensities to provide a stable base from which the body can create, absorb and distribute force. The muscular strength and endurance developed through this style of pushups is more easily transferable to other movements and even sport-specific training.
There are many different variations to the pushup, each of them requiring a different muscles to fire in different patterns. The regular pushup seems to recruit the arms, chest and core evenly if done properly. The yoga pushup asks more of the triceps and core. The wide pushup requires more chest engagement. The "diamond" pushup increases the demand from the triceps and chest. One can even vary the intensity of the pushup by placing their hands on an incline, level ground, decline, or even performing plyometric pushups with a clap in the air.
Have fun, play with different variations and feel how your body responds differently to each change. Pushups are very versatile and can be one of the best tools in your toolbox if used properly.