Male Baldness Info

is there anything that is detrimental to muscles other than poor diet and not working out?
I was wondering because i have been working out my arms(i workout every muscle not just my bis and tris) but i also play soccer as a goalkeeper.
so heres my question
does my goalkeepeing (diving, throwing, etc.) affect my biceps. will these activities make my biceps smaller or affect their growing process. i just decided to ask because a kid on my soccer team told me that when i dive for goalkeeping, i stretch out my biceps and they become smaller.
are there any other motions or awkward positions of my arms that can make my biceps smaller or affect their growing process after lifting?
also, does weight lifting speed up or affect male pattern baldness in any way?
thanks in advance

I’m 21yrs. old african american male w/ a full head of hair. I have small areas on each side of my head close to my ear were the hair there is thinner than the rest of my head. Similar to when a guy gets a taper hair cut except I don’t get those. It’s not bad like I’m going bald but I would like it to grow evenly w/ the rest of my hair. There’s no known baldness among parents, relatives or anything. Any products I can try to make my hair thicker or fuller?