Who said Luffy needed gear 2 to use it? Luffy in gear 1 managed to keep up with Bleuno just fine, in fact he only got faster after gear 2. Plus, why would soru put such stress on the body?
The way I understand it, and I could completely be wrong, is that in gear 1 Luffy was able to easily keep up with Blueno's soru. Gear 2 drastically increased not only his speed but the speed of his attacks as well while in gear 1 they were just regular speed and not amplified by the soru technique or something like that.
No. That's not true. Luffy could NOT keep up with Bleuno. To be more precise, he could, but it was a very even fight. I'm going to explain using actual screenshots, as this is not the first time there has been massive confusion about this.
At this point, Luffy does not know Rokushiki. He and Bleuno are almost a perfect match. Luffy expresses this equality by saying if this continues, it could go on for days, and they cannot defeat one another. His own words were "That's no good."
This is were Luffy first uses Gear Second. He pumps blood throughout his bloodtream, increasing heart rate, and swelling organs far by levels no normal human could survive. Because he is made of rubber, his organs are perfectly able to swell naturally without him dying. This is an explanation of Gear which I'm sure you all know.
Once he is in Gear Second, Luffy now knows that he can "assimilate" or basically "adopt" Bleuno's Rokushiki technique by copying it. Because he has learned such a handy tactic, he throws this vague statement out.
Now that Luffy has increased his blood pressure and can use Soru, he kicks Bleuno's ass pretty damn hard, until he finally figures it out.
This is the most important part of my little lecture. This line right here.
Luffy could NOT use Soru without enhancing his body with Gear Second.