This is the great Australian distance swimmer Grant Hackett. Pay attention to how he is doing his pull. His elbow bends but arm pulls back to the outside each time. Many athletes I coach try to pull straight back to their chest, which is indicative of a lack of hip rotation and a lot of struggle!
Watching Olympic swimmers on video is a good way to learn, but it is also a good way to try to do things that make no sense for a beginning triathlon swimmer. Keep in mind that these athletes are swimming 1 event, in a pool, and do not have to worry about saving up anything for another leg of the race. Also, even some of the top Olympic swimmmers have quirks in their stroke that would not be smart to copy- but they have perfected their strokes for the most part so that these little quirks don’t slow them down.
In other words, don’t feel like you need to study Hackett or Thorpe or Phelps and copy them exactly in order to achieve success in your triathlon swim!