How do Luffy's Gear attacks work?


Might just be me missing an explanation part in the manga, or just not
properly understanding at the time. But how does Luffy's Gear 2nd and 3rd
attacks work?

![](https://i.stack.imgur.com/K2yHr.png)




# [Gear
Second](http://onepiece.wikia.com/wiki/Gomu_Gomu_no_Mi/Gear_Second_Techniques)

[![](https://i.stack.imgur.com/h114Pm.jpg)](https://i.stack.imgur.com/h114P.jpg)

With gear second, Luffy increases his blood circulation by pumping his blood
through his body at higher speeds than normal. A normal human wouldn't be able
to withstand this kind of pressure on its veins' walls. If Luffy wasn't a
rubber boy, they would burst. The increase in blood flow results in a higher
discharge of red blood cells, which provide the human body with oxygen and
nutrients. The additional oxygen and nutrients would make the muscles work
more efficiently and thus result in higher speed and power. In sports this
process is called **[blood
doping](http://en.wikipedia.org/wiki/Blood_doping)**. In blood doping, the
discharge is increased by adding additional red blood cells, which were
extracted at an earlier time, instead of letting them flow faster.

Gear second also comes with **side affects**. The extreme oxygen usage would
result in an acceleration of his breathing and the increase in his metabolism
causes him to be hungrier than usual or even have a paralysis type effect
after prolonged use of it, like in the second fight with Rob Lucci. Due to the
acceleration and thus friction inside his body, he turns quite hot, which
results in his sweat evaporating right off his body. This explains the smoke
and redness of his skin.

Luffy obviously needs to keep pumping or the effect wears off. As it would
deplete his energy storage quite rapidly, he doesn't use gear second
constantly during fights. The increase in metabolism might also affect his
life expectancy as mentioned by Rob Lucci.

# [Gear
Third](http://onepiece.wikia.com/wiki/Gomu_Gomu_no_Mi/Gear_Third_Techniques)

[![](https://i.stack.imgur.com/Qx25Lm.jpg)](https://i.stack.imgur.com/Qx25L.jpg)

With gear third, Luffy bites into his thumb joint, making a small opening, and
blows very hard into it, which inflates his arm. He blows the **air inside his
bones** and since our skeleton fully connects all our joints, he can then
rearrange the amounts of air as he pleases through his body, without releasing
it accidentally. Luffy basically pushes the air towards his hands, stretching
his body, but also increasing the air-pressure. This would result in Luffy
having a larger area of attack (eg: the size of a giant's hand), and an
increased hardness due to the air pressure.

After the time-skip we can see how Luffy decreased the size of his arms, but
focused solely on the point of contact. He pushed all the air in his hands,
increasing the **air pressure and thus hardness** of his attacks. The air in
his arms would be wasted otherwise anyway. Also since it is air he is
carrying, it doesn't cost him much additional strength to move those large
hands, but the additional damage done due to the vast increase in area of
attack is well worth it.

Gear third also comes with **side affects**. Before the time-skip, we could
see Luffy become tiny after using this attack. After attacking, Luffy blows
out all additional air, resulting in a rapid decrease of body size. The rapid
decrease and massive amounts of energy needed to inflate and keep the air
where he likes it, makes him unable to retain his original size. I think it is
mainly due to the energy he needs to position the air where he wants and keep
it there, since Luffy didn't shrink after using his balloon attack. After the
timeskip and training with Rayleigh, Luffy became strong enough to keep his
body intact after using the 3rd Gear.

> # [Gear
> Fourth](http://onepiece.wikia.com/wiki/Gomu_Gomu_no_Mi/Gear_Fourth_Techniques)
>
>
> [![](https://i.stack.imgur.com/HtlEym.png)](https://i.stack.imgur.com/HtlEy.png)
> [![](https://i.stack.imgur.com/awpfem.png)](https://i.stack.imgur.com/JGkp9.png)  
>  
>  With gear fourth, Luffy, similarly to gear third, bites down on his body
> and blows air inside. The difference this time is that he bites down on his
> forearm and **blows air into his muscles** instead of his bones. By having
> air inside his muscles he can control their expansion and contraction and
> can thus control his muscles by displacing the air inside of them. People's
> muscles aren't as strong as their bones though, so if a normal person or
> even a normal rubber man would blow such amounts of air inside his muscles,
> they will explode due to the massive amount of pressure. That's why Luffy
> can only use gear fourth when coated in [Busoshoku
> Haki](http://onepiece.wikia.com/wiki/Haki/Busoshoku_Haki).  
>  
>  He then uses his Haki coated body, to further increase his manipulation
> over his body. **By changing the amounts of Haki he manipulates the
> elasticity of his rubber**. As a child you might have played around with
> rubber bands, and you might have noticed that the harder the elasticity, the
> harder the rebound will be. This is exactly what Luffy uses with his
> attacks. Before Gear Fourth, Luffy would throw his arm back to increase
> tensing, but now similar to Bellamy's [Spring
> Fruit](http://onepiece.wikia.com/wiki/Bane_Bane_no_Mi), he pushes his arm
> inside creating tensing, letting it hit the opponent much harder and faster.  
>  
>
> [![](https://i.stack.imgur.com/zBUSvm.png)](https://i.stack.imgur.com/zBUSv.png)  
>  
>  Having such great control over his Haki and his rubberiness, Gear Fourth
> has another advantage. **Luffy can now bypass other people's Busoshoku
> Haki** as mentioned [here](https://anime.stackexchange.com/a/11504/6166).
> Luffy was hit by Doflamingo, yet Doflamingo's attack bounced right off. By
> _fusing_ Haki with rubber, he is now freely controlling the expansion and
> contraction of his rubber despite what the other person throws at him.  
>  
>  Gear fourth also comes with **side affects**. The usage of such amounts of
> Haki comes at a price (as can be read
> [here](https://anime.stackexchange.com/a/11164/6166)). Therefore, at the
> time of writing (chapter 787), there is a time limit to using Gear Fourth.
> Luffy can only use _Boundman_ for 20 minutes and after that he is rendered
> unable to use any Haki for 10 more minutes. Another problem with having
> inflated muscles is that they become bouncier and thus making Luffy
> incapable of just standing still on the ground. Although this might change
> in the future, similar to the other gears. Luffy has overcome his other
> side-effects so he might overcome these ones too.




# [Gear
Second](http://onepiece.wikia.com/wiki/Gomu_Gomu_no_Mi/Gear_Second_Techniques)

[![](https://i.stack.imgur.com/h114Pm.jpg)](https://i.stack.imgur.com/h114P.jpg)

With gear second, Luffy increases his blood circulation by pumping his blood
through his body at higher speeds than normal. A normal human wouldn't be able
to withstand this kind of pressure on its veins' walls. If Luffy wasn't a
rubber boy, they would burst. The increase in blood flow results in a higher
discharge of red blood cells, which provide the human body with oxygen and
nutrients. The additional oxygen and nutrients would make the muscles work
more efficiently and thus result in higher speed and power. In sports this
process is called **[blood
doping](http://en.wikipedia.org/wiki/Blood_doping)**. In blood doping, the
discharge is increased by adding additional red blood cells, which were
extracted at an earlier time, instead of letting them flow faster.

Gear second also comes with **side affects**. The extreme oxygen usage would
result in an acceleration of his breathing and the increase in his metabolism
causes him to be hungrier than usual or even have a paralysis type effect
after prolonged use of it, like in the second fight with Rob Lucci. Due to the
acceleration and thus friction inside his body, he turns quite hot, which
results in his sweat evaporating right off his body. This explains the smoke
and redness of his skin.

Luffy obviously needs to keep pumping or the effect wears off. As it would
deplete his energy storage quite rapidly, he doesn't use gear second
constantly during fights. The increase in metabolism might also affect his
life expectancy as mentioned by Rob Lucci.

# [Gear
Third](http://onepiece.wikia.com/wiki/Gomu_Gomu_no_Mi/Gear_Third_Techniques)

[![](https://i.stack.imgur.com/Qx25Lm.jpg)](https://i.stack.imgur.com/Qx25L.jpg)

With gear third, Luffy bites into his thumb joint, making a small opening, and
blows very hard into it, which inflates his arm. He blows the **air inside his
bones** and since our skeleton fully connects all our joints, he can then
rearrange the amounts of air as he pleases through his body, without releasing
it accidentally. Luffy basically pushes the air towards his hands, stretching
his body, but also increasing the air-pressure. This would result in Luffy
having a larger area of attack (eg: the size of a giant's hand), and an
increased hardness due to the air pressure.

After the time-skip we can see how Luffy decreased the size of his arms, but
focused solely on the point of contact. He pushed all the air in his hands,
increasing the **air pressure and thus hardness** of his attacks. The air in
his arms would be wasted otherwise anyway. Also since it is air he is
carrying, it doesn't cost him much additional strength to move those large
hands, but the additional damage done due to the vast increase in area of
attack is well worth it.

Gear third also comes with **side affects**. Before the time-skip, we could
see Luffy become tiny after using this attack. After attacking, Luffy blows
out all additional air, resulting in a rapid decrease of body size. The rapid
decrease and massive amounts of energy needed to inflate and keep the air
where he likes it, makes him unable to retain his original size. I think it is
mainly due to the energy he needs to position the air where he wants and keep
it there, since Luffy didn't shrink after using his balloon attack. After the
timeskip and training with Rayleigh, Luffy became strong enough to keep his
body intact after using the 3rd Gear.

> # [Gear
> Fourth](http://onepiece.wikia.com/wiki/Gomu_Gomu_no_Mi/Gear_Fourth_Techniques)
>
>
> [![](https://i.stack.imgur.com/HtlEym.png)](https://i.stack.imgur.com/HtlEy.png)
> [![](https://i.stack.imgur.com/awpfem.png)](https://i.stack.imgur.com/JGkp9.png)  
>  
>  With gear fourth, Luffy, similarly to gear third, bites down on his body
> and blows air inside. The difference this time is that he bites down on his
> forearm and **blows air into his muscles** instead of his bones. By having
> air inside his muscles he can control their expansion and contraction and
> can thus control his muscles by displacing the air inside of them. People's
> muscles aren't as strong as their bones though, so if a normal person or
> even a normal rubber man would blow such amounts of air inside his muscles,
> they will explode due to the massive amount of pressure. That's why Luffy
> can only use gear fourth when coated in [Busoshoku
> Haki](http://onepiece.wikia.com/wiki/Haki/Busoshoku_Haki).  
>  
>  He then uses his Haki coated body, to further increase his manipulation
> over his body. **By changing the amounts of Haki he manipulates the
> elasticity of his rubber**. As a child you might have played around with
> rubber bands, and you might have noticed that the harder the elasticity, the
> harder the rebound will be. This is exactly what Luffy uses with his
> attacks. Before Gear Fourth, Luffy would throw his arm back to increase
> tensing, but now similar to Bellamy's [Spring
> Fruit](http://onepiece.wikia.com/wiki/Bane_Bane_no_Mi), he pushes his arm
> inside creating tensing, letting it hit the opponent much harder and faster.  
>  
>
> [![](https://i.stack.imgur.com/zBUSvm.png)](https://i.stack.imgur.com/zBUSv.png)  
>  
>  Having such great control over his Haki and his rubberiness, Gear Fourth
> has another advantage. **Luffy can now bypass other people's Busoshoku
> Haki** as mentioned [here](https://anime.stackexchange.com/a/11504/6166).
> Luffy was hit by Doflamingo, yet Doflamingo's attack bounced right off. By
> _fusing_ Haki with rubber, he is now freely controlling the expansion and
> contraction of his rubber despite what the other person throws at him.  
>  
>  Gear fourth also comes with **side affects**. The usage of such amounts of
> Haki comes at a price (as can be read
> [here](https://anime.stackexchange.com/a/11164/6166)). Therefore, at the
> time of writing (chapter 787), there is a time limit to using Gear Fourth.
> Luffy can only use _Boundman_ for 20 minutes and after that he is rendered
> unable to use any Haki for 10 more minutes. Another problem with having
> inflated muscles is that they become bouncier and thus making Luffy
> incapable of just standing still on the ground. Although this might change
> in the future, similar to the other gears. Luffy has overcome his other
> side-effects so he might overcome these ones too.

