I have a rather strange story about my muscle growth as a teen while having POIS. I am curious about this now as I'm starting to find I have circulation issues, and muscle growth is very related to good/bad circulation. This is why you see many muscle growth products advertising circulation enhancing products (many contain products that increase nitric oxide (NO) for example).
My strangeness is that by the age of 16, I had developed large neck, back and butt muscles, without exercising them. I was having people tell me "wow your neck is so thick, you look so big!" This is in contrast to the front of my body and arms, which were much less developed. I wasn't complaining, I looked like I was a physically fit guy (from the front and back) which helped me get the attention of women
But if you view me from the side, it was not such an appealing sight. Firstly, I have mild pectus excavatum, or a "bowl chest" which makes sort of a cave in the middle. This made my lower ribs stick out, and if I wore a shirt some mean people would say I looked like I had breasts. There was so much muscle mass on my back, that it gave me an imbalanced look from the side. I was almost hunchbacked, my neck and trapezoidal muscles were (are) so large. Also, my jaw may have not developed as it should, since I have a mild overbite and a small jaw.
Also strange are that I have narrow wrists and forearms, which looked quite scrawny when I was young. I later was motivated to exercise my arms and chest to try to improve my figure. I have developed large biceps/triceps and have larger chest muscles, but the chest has been very hard to grow. I am thinking, maybe I have circulation issues with the front of my torso that diverted blood/nutrients to my rear that caused it to grow so much but out of balance with the rest? If that's true, did this also contribute to my "bowl chest" by stopping/weakening it's growth, and the same for my forearms and jaw? Your front and back are innervated (supplied) by different nerves. The main nerve in the front is the vagus nerve, which if understimulated has been shown to cause depression (there is a treatment for depression where they install a vagus nerve stimulator in your body).
And equally strange is the muscle distribution in my legs. It's the same imbalance but reversed, the front (quadriceps) is really strong while the back (hamstrings) are seriously weaker. I ran on my highschool track team, and was a very good sprinter, and I could kick a soccer ball very hard and far. But I found out, when I played football (American), that I could not push others out of my way nearly as hard with my legs. This motion involves your rear leg (hamstrings) much more! On weight training days, I would be embarassed when I had to perform "squats" with my legs because I couldn't do half as much as the other guys for nearly as long. I work on those muscles to this day, and it has been hard to grow them!
I'm wondering if this has to do with POIS and my findings that I have circulation issues. My doctor told me I have Raynaud's Disease, where my hands and feet are purplish and blotchy showing bad circulation. Niacin, ginko, fenugreek all dilate your vessels, improving circulation and helping our POIS. I'm having trouble taking anything that promotes nitric oxide (NO), it's causing interactions with my psychiatric medications. I wish that didn't happen.
EDIT: the niacin flush is really centered around the front torso and arms. Coincidence or important?
Anyways, I'm curious if other guys here have similar stories. Also, in the days before niacin and vitamins, if I had a "hard" orgasm (basically where it felt REALLY good), the weaker muscles in the back on my leg would feel soooo sore the next day, like I had old-man muscles. I know you guys have soreness. Where is it the most?