Locked out?

[azx]

I have purchased Starting Strength and read through it, but a few questions still elude me.

Should I lock out my knees at the top of the squat? I lock my knees at the top at the movement because it gives me time to breathe in and out before i descend. And generally i think it's easier to complete the set this way.

However I'm unsure whether this is a safe practice, especially when the weight gets heavier.

I have read the book however I don't think this issue is addressed.

If the answer is no, why do we lock out the bench press but not the squat?
And should we lock out other exercises such as leg press?

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On an entirely different note, i haven't done any weight training for a while but am looking to get back into it. But i feel extremely inflexible especially in the lower back and legs. Are there any stretching routines that you would recommend?

Is it a bad idea to stretch statically before a set?

[Mark Rippetoe]

Yes, lock your knees at the top. That's how you rest between reps. Same with bench, press, deadlift, cleans, snatches, and every other exercise that uses a barbell, and this is obvious to everybody except people who use Swiss balls. I suspect you glanced through SS rather quickly and failed to notice that all the pictures at the top position showed locked joints.

If you're too tight to correctly perform the exercise, stretch. If you're sufficiently flexible, don't.

And if you're not training with weights right now, why are you asking me these questions?