Is it actually ever revealed how the Androids got so strong while being human?

[Jord]

I'm talking about 17 and 18 specifically. IIRC they were humans that got "modified" and thus got super strong. I never really bought that since they still retain their human bodies. 18 can give birth and both still bleed. I'd imagine that if a normal human would punch with the power of those 2, it would put a serious strain on the outside of their bodies.
I believe the only thing we know about these 2 is that they hide a bomb inside their bodies but has there been any official information on the modifications or what made them so strong?

[fleahop]

17 and 18

These 2 cause a lot of issues if we're talking about in-universe consistency.

From what I know they have "infinite energy reactors" inside of them and I can only imagine a ton of microscopic changes as well. It seems as if Gero was slowly moving from robotic engineering to bio engineering.

17 and 18 might have cellular changes like Cell did, but only to the max of Human ability, rather than some super mutant.

[Lionel]

Well they were genetically modified to be exact. I imagine it's probably like metamorphosing them into a higher class of humanoid that is stronger, more resilient and more adapt to the rigours of high intensity combat. Everything about them would have been transformed as a result of that genetic marker being changed so considerably.

Admittedly it's still a stretch to argue that they can go from being run-of-the-mill delinquents to the superior of the galaxy's prodigal tyrant just by having a reclusive scientist with limited technology available experiment with their bodies. Tao Pai Pai also became a cyborg but we saw how much good that did him. Maybe he didn't have the spectacular Dr Gero perform the procedure on him?

[Thanos]

Shouldn't never getting tired or running out of energy give someone a huge advantage? Even the Saiyans get tired and take long breaks, eat, sleep, etc... I mean, technically, couldn't #17 have been training on the island literally 24/7 since Cell was defeated? I suspect sleep would be unnecessary as well if energy doesn't deplete. Reaching SSJB tier might still be a stretch, but still...

[Jord]

I can see how perpentual energy helps, and it showed during #17 vs Piccolo but it still doesn't make sense how they were able to take huge blows from people with enough power to blow up planets.

[Anonymous Friend]

Shouldn't never getting tired or running out of energy give someone a huge advantage? Even the Saiyans get tired and take long breaks, eat, sleep, etc... I mean, technically, couldn't #17 have been training on the island literally 24/7 since Cell was defeated? I suspect sleep would be unnecessary as well if energy doesn't deplete. Reaching SSJB tier might still be a stretch, but still...

Think of them as always having a energy level of 10. Lesser enemies would definitely fall to them. Higher leveled enemies would pummel them, but as the pummel continues, their energy would lessen and lessen until it drops too low. It would require an enemy of sufficient energy to take them out long before their own energy drops to far low.

[theherodjl]

I can see how perpentual energy helps, and it showed during #17 vs Piccolo but it still doesn't make sense how they were able to take huge blows from people with enough power to blow up planets.

However Gero did it, being able to offer a never-ending supply of power to 17 & 18's bodies can certainly make them much more sturdy than any mere human. No doubt, Gero also did extensive study on the sheer power & progression of Goku's(as well as his opponents) attacks/techniques and he was able to figure out how to boost the Android's durability from there by artificially replicating the abilities of Ki.
There's not really as much of a mystery here as there is just not there not being specifics to Gero's process. Given all of the general weirdness in DB and how fighters from other universes have a myriad of strange abilities, I don't think it's at all unbelievable that Gero can make a couple of humans be on par with strong fighters.

[blacksymbiote]

Shouldn't never getting tired or running out of energy give someone a huge advantage? Even the Saiyans get tired and take long breaks, eat, sleep, etc... I mean, technically, couldn't #17 have been training on the island literally 24/7 since Cell was defeated? I suspect sleep would be unnecessary as well if energy doesn't deplete. Reaching SSJB tier might still be a stretch, but still...

By that same token, couldn't they have powered the genki dama indefinitely?

[Jord]

Shouldn't never getting tired or running out of energy give someone a huge advantage? Even the Saiyans get tired and take long breaks, eat, sleep, etc... I mean, technically, couldn't #17 have been training on the island literally 24/7 since Cell was defeated? I suspect sleep would be unnecessary as well if energy doesn't deplete. Reaching SSJB tier might still be a stretch, but still...

By that same token, couldn't they have powered the genki dama indefinitely?

Depends on if the energy they generate is the same as the KI used for the Genki Dama.