lol how do u know that i'm using my arms, can u feel my arms, and just because i'm not holding it for 2 or 3 seconds doesnt mean the muscle is not beig workerd
Neither I can feel your arms nor I saying that your rep speed is to fast. I agree with you 100% when you say: " just because i'm not holding it for 2 or 3 seconds doesnt mean the muscle is not beig workerd"
But it´s clear by the video that you are using mainly your arms to perform the rows. When you spend 6-10 hours a day in the Gym training people for a few years, our eyes become trained and we can see some little things that a inexperienced guy can´t. ( sorry form my bad English)
ANd I´m not saying your reps speed is too fast, but you are repeating this and trying to excuse yourself even people doesn´t mention this at their posts. But...
I strongly recomend to you do your reps a little slower ( not slow motion

) . Not saying that a faster rep speed doesn´t work - we can use Jay, Ronnie and Branch as examples. But they certainly are gifted guys when it comes to mind muscle conection.
For us, mortals, in most cases, it´s better to use slower ( not low motion ) rep speed.
Your back would get even better.