One of the hardest things to do in rowing is to learn to row relax. I describe good rowing as the one that requires the skill of relaxing the muscles that aren’t essential to the movement. If the non-essential muscles aren’t relaxed, they will cause tension that interferes in the desired movement and wastes energy. You can see in this video what relax rowing looks like.
Good coordination with regard to a certain movement can be defined as the right muscles tensing the right amount at the right speed at the right time. Most people trying to improve their movement ability for sports will therefore spend time lifting weights to train their ability to quickly and forcefully contract their muscles. But there is a flip side to the coin of good coordination which is equally important and often ignored. If coordination means all the right muscles firing at the right time, this also means that all the other muscles not involved in the movement must relax in the right places at the right speed at the right time.
Said that as you will be increasing fitness and power you might be losing efficiency on the movement on the water. This is why going fast on the water is not an easy thing to achieve. Doing the movement correctly and on a relax an efficient way is not an easy thing to teach and to learn.