What would be the results of training with King Kai for three years?

[Steven Bloodriver]

If during the 3 years before the arrival of Android 19 and Android 20, Goku, Vegeta, and the rest of the Z Fighters had trained under King Kai in the Otherworld, how would it have evolved their power progress?

[ChiefWamsutta]

Oooohhhh, good question. Well, I think it might hold Vegeta back because he probably needed the time in outer space to unlock SS1. King Kai would most likely get on his nerves.

It could help Piccolo, Goku and Gohan a lot for training because I think Goku was held back during that time period.

[Rubens]

Hm. I agree that Vegeta would probably refuse to train with Kaio and it would have been especially great for Goku, probably enough to surpass androids 17 & 18, because he wouldn't have Piccolo and Gohan holding him back, so Kaio could focus on them instead; yet, I don't think Piccolo and Gohan would get that much stronger because they already had a huge improvement in the first place. As for the earthlings... unless they learned the kaio-ken, I wouldn't bet on them to have relevant gains.

[floofychan333]

Really, I don't think it would have helped the important characters much. Maybe Kuririn, Tenshinhan and Yamcha would have somewhat benefited due to the fact that they had no way to access an area with high gravity, but Vegeta would not have needed it at all and it would have held him back.

[Lionel]

It's going to be awfully crowded on King Kai's planet. With training "more intense" than what even the humans and Piccolo first received, it's possible they could grow in strength greatly. I mean if the RoSaT is still useful to Goku and Vegeta in Super, why not King Kai's planet back during the preparation stages for the cyborgs? Just imagine if they all worked and sparred together too. I could see the humans shattering through into the tens of millions, maybe hundreds of millions since this is an even more intense training regimen of King Kai's in ten times normal gravity while having a Super Saiyan as a sparring partner. Give them Kaioken and they could probably handle the cyborgs all on their own. Piccolo and the Saiyans may not even be necessary.

[GigaDrill]

Before Super: They would crush 19 and 20, but if 17 and 18 are activated, there would still be a hard fight ahead for them
After Super: Yamcha becomes powerful enough to stomp Perfect Cell; the rest go fishing or something