I know this question isn't related to calisthenics but I seriously want to know it. My little brother has a really fast and good metabolism, he stay lean whatever he do, on the other hand I have a really slow metabolism since pre puberty, what I do I remain around 20℅ bodyfat. Why? Both of us are same brothers with same parents yet our metabolism is so different and I have noticed it into my friends and their siblings too, one is fat and other is lean. I remember when I was a kid I used be skinny and I remember I had consumed some doctor prescribed pills related to my anger issues but I remember they didn't worked on my anger issue but they sure did gave me crazy weight gain and super crazy hunger, but this is really old episode of my life, maybe 8 to 9 years ago, what's the problem now?

So as my lats and upper back are getting stronger, I can feel my lower back is lagging behind and I always feel discomfort in lower back but don't know how to train it in bodyweight calisthenics?

So I just recently reached 10 pull ups in my first set, but I felt like I could do 1 or 2 more but my forearms and grip were giving up and that affects at some amount to other sets as well.. What should I do about that?

If I want to increase my pull up numbers, should I train to failure like in the new vid w emom/drop sets or should I go for strength with form, currently at 8-9 chin over bar pull ups.

What are the aternate to pullups or pull routine at home ?i dont have a pullupbar or dip bar and i cant even buy one so what exercises i should do on pull routine ?