Let us say that someone is 10 times faster at thinking or reacting than the quickest human, assume that they can survive these feats and their muscles can perform them and their senses detect them.I have two questions would this person be able to block or catch arrows and what would this look like to a normal human? Feel free to add anything else cool you think they could achieve.
Assuming such a thing (the 10x speedup, I mean) is actually possible it would mean signals on neurons travel much faster and synaptic neurotransmitters bridge the gap in (much) less time.
In such a situation, even if bone/muscle infrastructure doesn't change much, it is very likely such a (super)man would be able to pick an arrow in flight.
As noted in comments there already are people who, through long training, are able to stop an arrow. These men, however, are pulling the feat in a completely different way. They, through training, learn exactly how much time it will take the arrow to be in the right position and send their hand to the "meeting point" just in time, like a pianist sending his fingers to hit keys in the exact time frame.
Fact is all these (and many other) gestures are "open loop": brain evaluates situation and start gesture; after that it's not possible to modify gesture because, simply, there's no time for feedback to go back to brain.
A sizable signal speedup, like that you envision, would completely change the game and allow direct feedback. This means gestures can be more precise and "reasoned" (in the sense gesture can be modified "on the flight").
Note: this speedup could allow arrow-stopping to be used in actual combat situation; what "normal(??) human" arrow catchers rely on is exact knowledge of where the arrow is going (archer is compliant), it wouldn't be possible if archer is free to chose his target.
A regular human can deflect or block an arrow with a sword after a decent training, I just spent about 15 minutes on youtube watching videos about it. The key moment is a duration of arrow flight - it must be long enough. If your character is 10 times faster, it will be relatively easy for him, especially after a training.
https://www.youtube.com/watch?v=7QLpYDQ0FSA - the video is about man trying to deflect an arrow with the sword. To the end of this 7 minute long video his chances to hit an arrow increases significantly. Probably he hits it by chance, yet still a short training helps a lot.
Actually, while it is possible for standard humans to catch arrows, that's only true up to a certain bow strength.
So in order to actually answer this question, we would need to know the speed at which the arrow was travelling, because, guess what, that really, really varies depending on type of bow, arrow and the like.
Like a 20-30 pound bow, sure, a normal human with training can do that, but something stronger means more speed and it's harder/impossible to do. Maybe be precise about the speed/type of arrows? At 10 times the normal speed, I would think even the higher range ones would be possible, up to a point.
But speed is not the only factor. Force is another. The super compound bows available today are super fast. And super fast means lots of energy and force. While your 10xs speed humans might be able to catch the arrow, it doesn't mean they will go away unscathed. In baseball, a glove is worn to protect the hand, but the ball moves more slowly, and the surface area is different. Friction, with catching a long arrow, is going to be an issue. Your humans might get hurt. (Not as big of a deal at under 30 pound draw, but even then, friction burns do happen).