High level VSRG stuff is quite similar to high level guitar playing in this aspect. Speed comes from good finger technique, not from finger strength. Playing faster than your finger technique can handle results in your fingers tensing up, causing the mid-song muscle fatigue you described. With better finger technique, you can play the same song at the same (or greater) speed using less strength, less movement and therefore with less muscle fatigue.Soul Evans wrote:
My stamina will get worse in that case, for 7k maybe but for 4k my stamina is really essential for 4k since 6 star stuff are really dense so even when i see myself doing better than what i normally do at half of the map, i just die down because stamina
On a slightly different note, playing songs where your fingers are constantly tensing up is probably not a good thing. You may be developing bad finger technique and get finger/hand injuries in the process. Playing at the limits of what you can comfortably play is better for preventing injuries and developing finger technique. Look at how some of the most skillful guitar players practiced, and you'll find they worked their way up to insane speeds by doing exactly this.