1. Muscle activation
Push Ups and Bench Press mainly do the same thing they target chest, front shoulders, triceps and lats in a pushing motion. However, when doing Bench Press the weight moves and the upper body is stabilised on a bench, which makes it easier to focus on your chest and push more weight. In Push Ups the body is moving instead, so the exercise involves more joint motion and importantly more core activation for stabilisation.
2. Can you replace Bench Press with Push Ups?
Getting stronger in Push Ups does not mean your Bench numbers will grow the same way, or vice versa. Bench Press is about absolute strength pushing the most weight possible, whereas Push Up is about relative strength how efficiently you can use your own body-weight. It all depends on your goals, both exercises can make you build muscle, get fitter and look better.
3. Push Ups offer you an accessible way to get results anywhere.
It's not easy to progress, but the challenge in learning new variations makes it fun. For example, One Arm Push Up is a great exercise that requires lots of strength but also involves core, hips and lower body which means you can transfer the strength gains to other real life movements such as throwing, punching, running. Here's more benefits and tips for Push Ups.
4. Bench Press requires weights, and even someone to assist you if you're lifting heavy.
But it also makes it easier to see faster maximum strength gains, if that's your main goal. But remember, the maximum strength you gain on your Bench Press can not directly transfer to real life functional movement.
Source: Oliver Williams