My training has been interrupted with several injuries, perhaps brought on by not knowing how to train properly or improper technique. One thing I have learned for certain is that technique is involved in all the sports in triathlon.
There are lots of people, including me, who started out saying, "you swim a little then bike a few miles then run. Who can't do that?"
Recognizing that I am not a great athlete, I tried to get better which, to me, meant adding more yardage in the pool and more mileage on the road. After I had been training for a while, with all the reading and talking to other triathletes I did, I heard several common themes. One of which referenced swimming, "don't do trash yardage."