Do different sports hurt my pitching?

I picked up tennis last year, and with summer ball my elbow got a little too stressed.

other than over use, does anybody know of anything bad tennis does to baseball mechanics?

Most likely you have “tennis elbow” or from swinging your racket or the medical name is ‘lateral epicondylitis’ and its most common with tennis players. It is caused when the tendons coming from the muscle of the forearm become inflamed at the point where they join causing pain and tenderness. My advice is if you want to be a really serious pitcher you might think about giving up tennis but then again there could be an alternate solution.

I’m throwing this out as just a possibility. I don’t know for sure that it is “legit”. It could be just hearsay.

I’ve heard that some sports/activities are joint-loosening and, therefore, are not a good mix with pitching. For example, I’ve heard swimming tends to loosen the shoulders. I’ve also heard that pitchers who thow opposite-handed from how they bat (e.g. a right handed pitcher who bats lefty) are more likely to be injured than pitchers who throw and bat with the same hand. The reason is swinging the bat is a loosening activity for the front shoulder which is your pitching shoulder if you pitch opposite from what you bat. It would seem backhanded swings with a tennis racket might be similar to swing a bat with the opposite hand in terms of opening up the shoulder.