Push-ups are great for upper body strength. They are great for your pecs, your biceps, triceps, lats, and core. You also work your glutes and a little of legs just by holding yourself up in plank though it is not meant to work that muscle entirely. A lot of people don't like push-ups when first starting out because they feel they can not do the full range of motion.
However, it is like I tell people, it doesn't matter how you do your push-ups as long as they are being done correctly and you give it your all. It doesn't matter how many you do just as long as you keep trying. Don't quit because you feel like you can not do it.
Push-ups are great and I highly recommend them. There are numerous of push-up variations. You just need to find the one that is right for you.
How to do push-up: Make sure hands are shoulder length apart while you are on your stomach. Then, make sure that your elbows are pointed towards your toes. A lot of people mistaken this position for a T shape which can cause injury on your rotator cuff if they are right at shoulder level. Make sure that your hands are right along the side of your chest. Make sure that your fingers are together and not spread apart. You can also use your fist to do your push-ups. Curl your toes inward, engage the core by tucking the pelvic in and tighten the glutes to raise yourself into a push-up using your arms completely then come about a couple of inches hovering the ground. Make sure that you are using full range of motion.
Modified: If you are not able to do a full push-up, then there are modifications. You can do them again a bench, chair, or even the wall until you feel safe and comfortable doing full plank one. You can even do them on your knees.
Below are the most common mistakes when doing your pushups:
1) Swayback: This usually happens when your hips are dipping into the ground and your body looks like a banana. You want your body to be like a board. This can cause lower back issues and cause injury in the that area.
2) Elevated Glutes: This is when you have your butt raise and you usually look like you are about the go into down dog position. This position is usually fixable when you engage your glutes muscles and lower your hips.
3)Breathing: People often forget to breath when they are working out let alone doing pushups. Make sure you are exhaling on the force of pushing and inhaling going down.
4) Head alignment: Make sure that your head is not below your heart or looking up as this can cause stress on the shoulder and neck area. Give yourself space between your neck and chin. Look 2 inches about your fingertips.
5) Dead legs: Sometimes, we forget to engage the leg muscles because we are so focused on upper body. It is so important to flex them while you are coming up and down. The core consist of 4 major muscle group: the core, back, glutes, and quads. All those muscles are working at once.
6)Half Reps: You have to completely go down in order to get the full benefits of this exercise. You are not going to get any results if you are only going half way. If you are not able to go fully down then you can always do a modification till you get strong enough to challenge yourself. Straighten your arms when you fully come up on your push-up and make sure your arms are at 90 degrees when going down.
7) Push-ups on the knees: If you have been doing these and are not noticing a difference in your strength over time, you could be possibly be doing them wrong and hitting the wrong chest muscles instead of the right ones. You can try doing Bear Crawl push-ups or bent knee push-ups which will help you target the right ones.
Overall, my opinion is that push-ups are the best if you don't have access to weights, if you are trying to build your strength, and are more effective than weight bearing exercises without the extra pounds.