I am 5'9 and 52kg (114lbs), so you can imagine, I am extremely skinny and I've always tried to gain some weight. Regardless, I've always loved running, I used to run a lot before but I am not running much these days. But still whenever I run my friends discourage me from running telling me that I shouldn't run as I'm very skinny and it will prevent me from gaining mass. All this has a made a drastic change in my mindset and now I have started to question myself if I should really be running. What do you guys think? Is it okay to run if I want to gain mass?