Kaioken inspired the Eight Gates (Naruto) and Gear 2nd (One Piece)

[Young-Jah]

Did the Kaioken actually inspired the Eight Gates and Gear Second techniques in both Naruto and One Piece.

Or false?

[ankokudaishogun]

"using all your power risking injury" is a common martial arts trope

[GhostEmperorX]

I once thought the same at least as far as the Eight Gates (especially when Rock Lee was moving around like a DBZ character in that first match), but...

"using all your power risking injury" is a common martial arts trope

this is most likely the case.

[Matches Malone]

Considering both Kishimoto and Oda said multiple times that not only was DB their favorite manga growing up, but it also inspired both of their works, I think it's safe to say the answer is yes.

"using all your power risking injury" is a common martial arts trope.

That DB made popular, which so happens to be the manga a lot of the current authors read growing up.

[Young-Jah]

Considering both Kishimoto and Oda said multiple times that not only was DB their favorite manga growing up, but it also inspired both of their works, I think it's safe to say the answer is yes.

"using all your power risking injury" is a common martial arts trope.

That DB made popular, which so happens to be the manga a lot of the current authors read growing up.

How many inspirations did Oda and Kishimoto used from DB

[GhostEmperorX]

Considering both Kishimoto and Oda said multiple times that not only was DB their favorite manga growing up, but it also inspired both of their works, I think it's safe to say the answer is yes.

"using all your power risking injury" is a common martial arts trope.

That DB made popular, which so happens to be the manga a lot of the current authors read growing up.

How many inspirations did Oda and Kishimoto used from DB

Can't speak for Oda, but Kishimoto uses a lot.
Naruto's very outfit colour in part 1 is literally taken off Goku's Gi (orange and blue) and sharing roles like being the bottom of the pack initially (albeit that one has a prophecy behind him as well as a special bloodline and the other doesn't), and one could say that Sasuke's outfit even resembles Vegeta's in terms of colour (blue and white) and they're the elite rivals of the initially lower class MC's. The 4-tailed beast is a reference to Journey to the West since it's an ape with the design of the original Son Goku but giving it 4 tails is reminiscent of the 4-star Dragon Ball and having its host be named Roshi compounds the reference. Madara's hair even looks just like that of Raditz.
And then likely a bunch of other things DB either came up with or popularized, such as the Kienzan/Rasenshuriken (even though this was originally from Ultraman). The posing for both attack preparations is the same, if anything.

[SupremeKai25]

Looks like he also took DBZ power-ups and power creep as an inspiration during the War arc.

[Psajdak]

Toshiro Hitsugaya from Bleach looks like whitehaired Super Saiyan.

[FoolsGil]

It's possible, its a known fact that Oda and Kishimoto (and Kubo) were heavily inspired by Dragonball when creating their serieses.

[Polyphase Avatron]

IIRC Gear 2 doesn't really put the body at risk, it's basically just a transformation that increases speed.

[Miracles]

Of course. Oda and Kishimoto are Toriyama's kids. Naturally they will copy daddy.

[FoolsGil]

IIRC Gear 2 doesn't really put the body at risk, it's basically just a transformation that increases speed.

Actually it was said in One Piece Gear 2 was taking time off of Luffy's lifespan.