We lose mobility as we age.

When you were a baby, you were able to stick your foot in your mouth. Think about that. Sticking your foot in your mouth. Try to do that now, and every 49 out of 50 of you will most likely find this to be laughable.

Why does this even matter? Well, an extremely simplified way of putting it is that if you're unable to draw ROM (range of motion) from a joint that is supposed to be able to provide it, then you're going to compensate at a joint that is not supposed to move. A quick example of this is that many people with low back pain tend to have stiff hips (their back is moving to pick up the slack, due to lack of mobility at the hips).

If you’re a weightlifter, better mobility will improve your positioning during the set-up, thus giving you a greater mechanical advantage. This will allow you to move even heavier weight, and, more importantly, do it safely.
If you’re an athlete, greater mobility is going to help you produce more force (a quick example being that improved dorsiflexion ROM at the ankle will prevent you from prematurely drifting on to the ball of the foot, thus allowing more force to come from the powerful posterior chain).
Heck, even if all you care about is tending your garden well into your years, you’re be at reduced risk of back pain due to the fact you can sit into a deep squat without significant rounding of your lumbar spine.

I recently came across an old picture of myself getting ready to face-off, back in my competitive lacrosse days, that brought home the very point I addressed above (I'm in the red/black on the left): As you can see, I'm as low to the ground as possible. When getting into position for a face-off in lacrosse, it's generally accepted that one of the keys to gaining an immediate advantage over your opponent is to be lower than they are.

When looking at this picture, I was promptly struck by the fact that it was much easier for me to get into this position back in high school than it would be for me today. I didn't know it at the time, but I was asking my body to provide quite a bit of ROM at my ankle and hip joints, and also throughout my entire thoracic spine. This, in turn, would put me in better position to utterly destroy him win the face-off.

Anyway, this picture gave me a pretty large "pillow womp" to the face. I realized that, while I do perform about 10 minutes of mobility drills before my lifting sessions, it's not even close to the quantity I need to undue the hours of sitting (in my car, in coffee shops, at my desk, etc.) each week. Gradually, over time, I have lost mobility and created more positional problems for myself. I decided to make a greater effort in prioritizing my movement quality via some quality drills (which I show below).

Given that most of you spend 40+ hours per week (and this is probably giving you more than deserved credit), you'd be wise to listen up. This past Sunday I spent a good deal of time fixing up all the sticky junk restricting my motion. I took some pictures of some of the drills I've found to be the "best" in hopes that you can benefit, too.

Spend two minutes per side for most of these drills. Remember, doing some quick bodyweight squats before your lifting session isn't enough to undue the abuse you give your body from sitting (aka "the slow death position") 160 hours a month.

Before I begin, I can thank Kelly Starrett of the Mobility Project for a few of these drills. He's doing a great thing over there (to put it mildly) by encouraging people to daily work on their grody joint mobility.

For the first three, you can use any table or bench. The last picture shows a variation I'll use in coffee shops (not kidding), as it keeps my foot off the table. Think "chest tall" for all of these. You'll cover hip flexion+external rotation, throracic spine extension, and get in a bit of adductor work, too (in the first photo).

Next, we'll receive a bit of improved dorsiflexion ROM (in the top left photo), as well as some much-needed work on the iliopsoas and rectus femoris (a few of the hip flexors) in the right and bottom photos. You can use any wall or elevated surface for ankle drill, and can use a couch, chair, etc. for the right one. You'll need a sturdy resistance band for the bottom mob shown.