Physical Education

You should aim for a greater variety of exercises so that your body doesn't get adapted just for push-ups.

You are reaching the limits of what your muscles can accomplish. The only way to increase this limit, is to gain muscle mass. Also, if you're doing push ups, try to do pull ups to balance your physique. Push ups train mostly chest and triceps, if you only focus on that you'll create muscle imbalances in your body in the long term. A strong chest with a weak back will lead to poor posture, which in IT is quite a common problem.

Yea. In addition to the other responses, you also have to change your diet. You have to count macros and try to hit your protein target.

There are different push up variations, try harder variations so you dont have to do 30 reps to reach failure. Push ups are for triceps and chest specifically so right now you are only developing these muscles, try different variations so you can get a better rounded routine.

Reaching failure (arms giving out in this case) is precisely what you want for muscle growth, the trick is reaching it on a moderate amount of reps (i.e. 8-12) for more optimal growth + time efficiency, thats why you have to try a harder variation or increase weight.

Maybe try to make your push-ups slower on the descent so every rep is more demanding for your muscles. After about 15 reps for any exercise it's very hard to condition your muscles. I don't know how recently you've been training, but if it's less than a couples months since you've been doing only 5, I think you're probably doing push-ups in a fast pace, almost like an aerobic exercise. Take your time for every rep, and try not to focus on the quantity of push-ups, but on their quality, you'll be conditioning your muscles with much more intensity.

Second thing, I think you're spacing well your exercises, but remember your muscles can take up to 72 hours to fully rest and recover, depending on the intensity of your exercises. Even if you feel just a bit sore it's probably not good to train yet, and you can take the opportunity to focus on other muscles, such as your legs.

Another thing I can suggest so you can condition your muscles in a more intense manner through push-ups is by doing declined (not inclined) push-ups, where your legs are in a greater height than your upper body. This greatly increases the intensity of your push-ups.

Nowadays on my chest/triceps day, I usually start with declined push-ups for about 3 series, then normal push-ups, and finally inclined push-ups. Basically begin with a more intense exercise and work your way through the easier ones. I greatly improved the conditioning of my upper body through this routine.

I don't know how efficient it is, but the "greasing the groove" approach was apparently designed by a trainer in the USSR to avoid muscle failure

I find this as well, I think it's a common problem. I'm no expert, but I think switching up the number of pushups you do day to day, sometimes less, sometimes pushing a bit more, will help prevent your muscle programming a certain number you can do.

I've had reasonable success in getting past that barrier with following a schedule like this: https://hundredpushups.com/

I'm most certain this is a mental thing, if I'm alone I usually don't do much because I get lazy but when I'm in Systema classes and you have someone there telling you to do 100 push ups you just do them. You need to start shutting up the voice in your head telling you you cant do it. If you say you're doing 25 push ups a day with no problem I can't see how you can't start adding at least 5 or 10 more, but who knows.

Your strength progression is limited by your stamina. You should try harder variations of the exercise. And for that, let me introduce you to Chris Heria.

https://youtu.be/EjzCljYS5Po

The important thing is to find ways to progress from workout to workout. If you're capping out at 2 sets of 28, then switch it up. Break up your target total reps and do more sets with less reps (If you're aiming for 60 push-ups for the day, try doing 4 sets of 15 instead).

For muscle growth, general rule of thumb is that you wanna rest at least a day before your next workout targeting a major muscle group (in the case of pushups, it's chest/triceps). Same for strength programming.

However, given that you are still in the "noob gain" phase of strength fitness, you got a lot more room for progression no matter what your routine is, as long as you are consistently working out. Unless you're doing hundreds a day, push-ups with good form (important!) are also pretty easy on your body compared to other exercises and you should be able to get away with doing them as frequently as you want. You could do them 7 days a week and repeat.

My advice, find a beginner calisthenics programs and do your best to stick to that for a few months. That's gonna give you a solid foundation of strength, endurance, and mobility for when you eventually get the desire to branch out to other programming.

Credentials: Not a fitness expert by any means, but I have consistently been doing powerlifting workouts for over a decade and have gone through several programs, bodyweight programming included.