- In the 3rd episode during the first P.E. test session, Kaizaki fumbles the first test because his shoulders go so stiff he can't rotate them well enough to toss the ball. He notes to himself that adults need to warm up or they get hurt. But, that's true for teenagers too, isn't it? Besides, he is in a teenager's body at the time... Yes, his brain forgot a lot since then but if his body is returned to its previous state that means it's lost its stiffness, right?
- It is explained earlier that Kaizaki's body, while looking 17 years of age, is still physically 27. This is also shown later as his scraped knee and face are still bandaged long after Kariu says he should have healed. Also, while teenagers would need to stretch before physical exertion just like adults, Japanese school students are, by and large, way more active than someone working a day job. It stands to reason that it might have been a few weeks since Oga engaged his shoulders and that was why he only threw it two meters, but for Kaizaki it's likely been years since he used his shoulder muscles for anything more than bowing.
Headscratchers / ReLIFE