Push-ups are a perennial exercise for a very good reason: they activate multiple major muscles all up and down the front and back of the torso. If you're trying to strengthen your back muscles, push-ups can help when you make certain adjustments. Keep in mind that no push-up will comprehensively train this area, however.
Read More: The 20 Best Body Weight Back Exercises
Enhancing the Basic Push-Up
The standard push-up doesn't work the latissimus dorsi, or "lats, which are the muscles under the shoulder blades that enhance the highly coveted "V" form. But they do work the back extensor muscles (erector spinae) that run the length of the spin on either side, allowing us to stand upright and rotate our trunks.
When doing pushups, keeping your shoulder blades pulled back increases the activation of the rhomboid and trapezius muscles located in the upper back.
Another lesser known benefit of doing push-ups is that they work the abdominal muscles, which are all-important for back stability. They particularly work the transverse abdominus (TA), which is the deepest lying of all the abdominal muscles. Though not visible like the rectus abdominus, it plays a key role in pelvic stability and weakness in it has been linked to lower back pain. To enhance activation of the TA when doing push-ups, brace your abdomen as if you're expecting a punch in the gut and maintain the tension through the exercise.
Avoiding Lower Back Stress
While basic push-ups can be very good for the back, some people may find that they cause pain, particularly in the lower back. That's because the push-up position puts pressure on the trunk muscles, which in turn can stress the lumbar vertebrae. In a study published in the Journal of Physical Therapy Science in 2014, doing push-ups with the trunk flexed upward -- as in a "Downward-Facing Dog" position in yoga -- was shown to prevent over-extension of the lower back. This position was also shown to cause more activation of the serratus anterior, the muscle that pulls the shoulder blades forward and around the rib cage.
The Pike Press is the flexed-trunk, hard core variation mentioned above with a big payoff for the whole of the trapezius, the flat, wide muscle that covers back of the neck and most of the upper back. It also activates the serratus anterior.
Place two benches side by side but with enough space between them for your head to fit through. Kneel lengthwise with one knee on each bench and your hands at one end of the benches and feet at the other.
Lift your butt high up into the air so that your body approaches an upside down V position, keeping your arms, back and knees straight.
Bend your arms and lower your head between the ends of the two benches, then push back up to the original position.
Read More: 10 Different Types of Push-Ups