Originally Posted by
Ren Ying Ying
The way I see it, while internal power can increase both your overall strength and speed, its usage is still dependent on technique (ie. XL18Z/Heavy Iron Sword uses internal power to amplify strength while Jade Maiden/Sunflower uses internal power to increase speed). Hence, it doesn't necessarily make sense for GJ to use his internal power for something that is not his forte. To draw an analogy, it's like comparing a tank to a race car. Both have extremely powerful engines, but are used for different purposes. Putting armor on the race car probably isn't going to make it that much stronger than the tank and making the tank lighter probably isn't going to make it faster than the race car.
Or, in another comparison, the marathon runner and the sprinter. Both would improve with increased conditioning and muscle strength. However, the types of muscles that benefit the marathoner is different from the ones that benefit the sprinter. Hence, if you took the naturally built marathon runner than tried to train him as a sprinter, he will likely still be very fast, but not as fast as the naturally built sprinter (and vice versa). Hence, it would be a waste of his talents. Likewise, trying to make a power-dominant art into a speed-dependent art is a waste.
In this case, GJ is still much faster than the average joe, but speed is not his forte. GJ's signature art of XL18Z relies on power, not speed. A powerful XL18Z is much more effective than a fast XL18Z. Like in all things, it is good to be versatile, but better to play with your strengths. The non-internal-power-buffered speed of XLN's arts (AT's arts) is much faster than GJ's arts. Hence, if the two were to be involved in a pure speed contest, GJ will have to use much more of his internal power to catch up with XLN's. The only question is, how much faster is the AT arts compared to GJ's arts and how much internal power does GJ need to use to match XLN's speed. The specific values to both of these is arbitrary and really depends on your opinion.
However, keep in mind that GWM did (stupidly) try to compete with XLN in speed and his internal power at that point in the story is more or less in the same range as GJ's...and yet he could not "outspeed" her. Hence, using the same criteria, at that point in the story, it is unlikely that GJ could be faster than XLN. Unless, of course, you think that GJ is significantly faster than GWM.