Question about knee pain and doing legs, what gives?

[Strut99GT]

Bros, if you don't already know from my profile, I am a tennis player. One odd thing that has been happening to me lately, though, is that my knees hurt when I'm running and do a "hard stop" on the tennis court. They never did hurt before I started lifting legs pretty seriously a month ago.

My knees don't hurt while I'm lifting, and they don't hurt when I'm sitting around, walking, or any of the typical everyday movements. It seems to me that because I'm doing legs and they are getting much stronger, I should be able to withsand the rigors of running around on a court much better. Do you all have any comments/advice for me, or have any idea what's going on? Is the general idea that while you are in your rest period for a muscle you should expose it to any exertion at all? I generally don't play when I'm really sore for the first couple days after a leg workout, but do do play sometimes when my legs are "sort of" sore. Thoughts?

[KeyMastur]

Bro, I run around on hard concrete most of the day as a valet and I've got the same problem. Before I was doing this valet shit, my knees never hurt, but now there is pain in both, sometimes just the left. When I lift legs, I take a day off from work, and then lift the next morning - giving my knees (tendons, joints, all that shit) to rest up.

[Strut99GT]

Key - yeah, I usually give it at least a day of rest, but I'm talking about in general...the knees feel weak no matter how much rest I've had.

I guess what I'm wondering is which exercises have the most negative effect on the knees. These days, my leg exercises are the basics: squats, deads, lunges, calf raises. I used to do leg extensions/curls, but I heard that extensions were hard on the knees, so I cut them out. Thoughts?

[BIG TEXAN]

Hell, what lift isn't hard on the knee's?!?!? I've got bad knees and have learned to live with it. Anti-infalmmatories, ice and wraps are my new best friends!LOL Running on hard surfaces will do this to ya. try to give 'em a little rest and maybe in time it'll go away. back in college when I ran track and my knees acted up I'd run in the grass for practice instead of on the track and a couple of weeks later the pain would start to go away.

[Strut99GT]

LOL unfortunately I will have to pay top dollar to play on any court other than a hard court, so that's not in the cards.