I'm a newbie so forgive me if this has been discussed - I tried searching but couldn't find an answer to this question: I am an older soccer player (53) and have been on LC for about 2 months. I've been playing soccer my entire life without too many injuries. Tonight I stretched well and went out to play. Within 5 minutes all of my leg muscles felt tight and I had to stop after I strained my calf muscle. Did the LC diet cause this?

Perhaps. LC causes a lot of water to go through the kidneys and take minerals with it. I take a multi vitamin and Potassium. Ask your doctor about a Potassium prescription or get some salt substitute with Potassium.

Five minutes seems really quick though.

The calf muscle has some of the best blood circulation in the body as it tends to be constantly worked throughout the day. It seems really odd to hear that it strained. I'd keep an eye on it. It may have nothing to do with LC-ing and attributing it to a LC diet could delay having the cause properly diagnosed.