again, it's situational. i'll use my story as an example. someone who is generally fat and lazy and has a terrible outlook on life and low self-esteem most likely will not be very social or be able to help in stressful situations. but, then that person goes to the gym, starts getting into it, turns it into a lifestyle and ends up changing their body, which builds self-esteem and confidence and eventually the person is more social, is helpful when people are moving, can react faster and is stronger when it may be needed will most likely have "more balls" than the person they used to be. thus, going to the gym caused that person to "grow" balls. I mean, you're not gonna see a 300lb behemoth running to take down a shooter most likely. you want to rob someone, you aim for the fat guy, not the in-shape guy.