And this is why I had Lopu mention that he's needed to wrap the fight up quickly and why I showed him tired in earlier pages. Some might have also guessed this from the fact that he has a cane sometimes and his bad leg has been brought up before.
ガーン (gaan) is a clang and ザシュ (zashu) is a slash. ドッシュ (dosshu) is bone cutting. That's not exactly what's happening to his leg, but I felt it fitting regardless.
Batuu: Lo-poop just doesn't have any endurance anymore -w-