I remember watching a video which explained why. Basically, the reason is because the song is generic (friendly reminder that generic does not mean bad). It follows a pattern that many other soundtracks used, especially for action.
"You Say Run" starts off quite calm, which is to build up the intensity until the fight starts. This is somewhat of a requirement for action scenes, otherwise, they would just feel too sudden and out of place.
When the drums kick in, that's when the first part of the fight starts. There's nothing much to say for this part. It's just an amazing soundtrack that accompany a great fight.
When things get a bit calmer, it goes into a "thinking phase". Usually, characters find that they are unable to defeat another character during a fight. So naturally, they start thinking about what weak points they could potentially exploit. As to avoid clashing with the intensity of the fight, the soundtrack has to become more calm to accompany the atmosphere of a fighter thinking about their next move.
Also, notice how their is a crescendo (a gradual increase in volume) before the final part. This is once again to hype the viewer up for the final showdown.
Afterwards, it's pretty straightforward. The character goes out of this "thinking phase", and is ready to defeat their opponent. As such, the music becomes intense, to accompany the atmosphere that this battle weighs. And it just follows through with it, until the fight is over.
To recap, many fights follow the formula of:
Intensity building up for the fight → First part of the fight → Fighter thinks of a way to exploit opponent's weakness → Final part of the fight (maximum hype levels)
And "You Say Run" is essentially the perfect fit for this "fight formula". This OST follows the exact pattern that not only the fights in BNHA have, but the same pattern that can be found in nearly any fight scene. Therefore, it's natural that it goes with everything, as many other fights have this "fight formula".
Or this could just be completely wrong and it's just meme culture being embraced by everything. |