According to the official character book, Shoji has a power of "5/5". I don't know what exactly the power means for all character? But for a character who doesn't have any emitter ability, I guess it has to be related to strength, yet Shoji as far as I remember is never shown to be as strong as many other characters. Other character like Rikido Sato, who can increase his strength to five times and can destroy walls with it, it's rated "4/5". My question is, does Shoji have some level of superhuman strength or what power he has that justify his "5/5" rating of power in the official character book?
Right taking into account what Merlyn said aka that shouji in grip strength measures 540 kgs. Just to give you a reminder, the force that is needed to crush a human skull is 235 kg, so Shouji could potentially break all the bones in your body with relative ease, so yes he absolutely deserves the 5/5 scoring in power.
You don't have to have a superpower to be super in My Hero Academia world. Just look at Eraserhead or Stain. Neither of them have power related quirks, yet both are extremely tough in physical combat. Shoji is like that. Keep in mind that he placed 6th in the Physical fitness test despite his quirk doing very little to enhance physical capabilities.
Ok, I found an accurate answer for this. In episode 5 of season 1 they make a test of strenght and Shoji measures 540 kgs in the test by pressuring with his hand in a device with 3 hands.