The Squat. We squat intuitively and effortlessly as toddlers, but as we get older, that skill is often lost. Here are the highlights of how (and why) to squat.
To quote Mark Rippetoe, "the squat is the only exercise in the weight room that trains the recruitment of the entire posterior chain in a way that is progressively improvable... (It is) the best strength exercise there is." (from Starting Strength).
Why is that important? Well, as I learned in massage school, most of us are a mess of muscle imbalance. Our daily activities tend to only recruit the front (anterior) muscles of our bodies. We drive, cook, clean, carry things, and operate our many devices using mostly front muscles. We also sit a lot, which keeps our hips in tight, passive flexion (vs. hip extension, which is the key movement of the squat).
We don't tend to use our glutes, hamstrings, lower and mid traps (back muscles), or adductors (groin muscles) much at all. In fact, unless there has been a specific trauma or injury to the body, most muscle pain is caused by weakness, created by this significant imbalance over time. One of my favorite teachers in school described the relationship as a very lopsided tug-of-war. The biceps, pecs, forearm flexors, and quads are used to doing all the work... they pull and pull, and the opposite muscles get pulled... and get painful.
Some people claim squatting is bad for your knees. But a properly done squat doesn't hurt the knees. Just ask a toddler.
So, how does one properly squat? Honestly, it does take some time to learn how to squat correctly (especially if you're going to add weights). I highly suggest Mark Rippetoe's book -- yes, it's technical and a bit dense, but for me it was worth the read.
I like the article ("6 Ways You're Squatting Wrong") and the video is pretty good -- however, I don't agree with her warning that the knees should never go past the ankles. In fact, point 6 of the articles explains why this is not necessarily true.
So try going back to your toddler roots by squatting a little everyday!
FYI, I found another squat video that I like much better than the one listed above: