Swimming mystery solved

Actually two mysteries and they are not real mysteries but...

Looking back at my swimming workouts, I see the pattern that I am not able to hit my paces if I do something stupid the day before (arms, back weights) or if I do a lot of paddle work during the workout before the hard intervals.
For example on Tuesday I did no paddle work and I felt great on intervals later. Last week, paddle work and I did not hit the paces. Today, the same, a lot of paddle work (4x25 with bands and paddles only and then 3x200s at steady pace, so it was even harder than usual) and I could not hit my paces for 150s afterwards. I tried but I could not move!
Actually come to think about it, maybe it is not that I am too tired after paddles, because it is just weirdness of using only arms as opposed to paddles. Because then I took 1 min complete break and did 100s and I was able to hit paces, although it was a complete surprise to me! It is either that that 1 min break helped me a lot, or that my theory about paddles squeezing all strength out of me is not valid.
I know I am not making much sense here, I should ave thought this through before writing this, but whatever, hardly anyone reads it anyway.
So and my ability to hit paces on 100s even after paddles leads to another "mystery solved". Efficient form! I tried really hard on those 100 to rotate the hips, keep high elbows, keep chin tucked in, not to lift head when breathing and use core strength. And it seems that it worked (since I was able to hit paces even after paddle work assuming my theory about paddles killing me for the rest of the workout is valid).
Great! Keep up a good work, mmmonyka!!!
I went to do some arms, core, back strengthening exercises afterwards.

I also did 9 miles + strides before swimming. I saw 5 little dears, one warrior dogs that freaked me out and parts of my run were more like high knees drill and not like actual running since I had to run through snow because there was not path in snow in all parts yet. This snow running is a great workout, by the way. I must use different muscles to stabilize myself and it always leaves me pretty tired and sore.
Although I am not sure whether this is good for the ITB. It is either very bad because my knee and ITB must work extra hard on uneven surface with sliding in every direction. Or it is very good because using all muscles helps me to eliminate any muscle imbalances in my legs and thus helping the ITB.