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 itīs 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 canīt. ( sorry form my bad English)
ANd Iīm not saying your reps speed is too fast, but you are repeating this and trying to excuse yourself even people doesnīt 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 doesnīt 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, itīs better to use slower ( not low motion ) rep speed.
Your back would get even better.