In the childhood cartoon "Popeye the Sailor", Popeye would eat spinach whenever he wanted to gain a lot of additional strength. At that time, I really wished a food that could do that existed!
I never thought that recent research coming out of Sweden would show that spinach really can improve muscle function. It naturally contains nitrates that can strengthen muscles. It turn out that Popeye becoming stronger after eating spinach could actually be a true story.