Body language is definitely a factor. I wouldn't put it in the top 5 or anything, but all factors add up.
Naruto runnins is not virgin walking. Although the torso is inclined forward, this is done by leaning forward (a sprint) which is very different than rounding the spine and protracting the shoulders forward.
Naruto running is a very masculine kind of running if done properly because the shoulders are drawn back conflidently, thrusting the chest forward.
Posture matters here too though. You can see, for example, how Neji Hyuuga's posture is far superior to Naruto Uzumaki's while running. His spine is straighty and his shoulders are less slumped.
Neji is much more biomechanically efficient, basically using the "pose method" or running (landing on forefoot) whereas Naruto is doing standard heel-strike bullshit and randomly flailing his leg in a bent position before he even begins hip flexion, whereas Neji flexes the hip and knee joints in a coordinated motion which looks much better.
You can see that fellow-incel Shikamaru is doing similar bullshit. These betas basically have their hips cowardly centered atop their ground-contact leg, whereas alphas like Kiba/Negi have their pelvic weight ahead of their striking leg. They're running like they're not afraid of their momentum or falling forward onto their face, showing off their superior balance.
The Naruto/Shikamaru type pose is scared, keeping the pelvis back, being afraid of falling forward due to inexperience. They don't thrust their cocks confidently forward like Neji and Kiba do, being confident masculine alphas.
Choji is a fucking enigma because he actually has a decent Neji/Kiba type posture despite being a fatass. He only goes to show a perfect example of how posture is just a component but won't solve all your problems on its own, which applies to ALL factors of attractiveness.