For the sake of today's post, I'd like to throw all exercises into one of three categories:

1) Hard: They look difficult to do, and if done properly they are difficult to do. There is no escaping it, yet we do these exercises because they benefit us in some way. For me, the first exercise that comes to mind is a 24 inch box jump. Doing one is challenging, but repeating the jumps without rest for 30 repetitions is crazy hard. But, if you're a runner, skier, or just want to be really fit - it's effective.

2) Easy: They look easy to do, and are generally easy to perform. Often times overlooked as "time wasters" because they present very little challenge, these exercises serve a great purpose and usually help us do the harder exercises better. Stretching, back extensions and postural exercises fall into this category. They're important and can be preventive of injury.

3) Unassuming: They look easy enough, but not all-out-hard. This is the exercise you think you'll have no problem doing...until you start doing it. Things become difficult quickly. Functional exercises using your own body weight fall into this category. Everyone has their dreaded favorite that they know will push them - and hit the muscles that they'll feel the next morning.

Here are mine:

Warrior 2
Take just about any yoga class, and you'll likely fall into Warrior 2 at some point, perhaps many, many times. Moving through the position quickly in a "flow" is great in that it works the quadriceps (top of the thigh) and hamstrings (bottom of the thigh), but when you hold this position for an extended period of time, you start working a lot more! Much of yoga concentrates on breath, and according to Todd Rhodes, yoga instructor extraordinaire at Lincoln Park Athletic Club, "if you hold longer than a few breaths - 5 to 10, you'll begin to work the deeper muscles in the glutes (your bottom), all the stabilizers around the knees and you'll work the calves and muscles around the ankle." I secretly refer to Todd as 'Todd Todd the yoga god' because he really knows his stuff. One additional muscle group I'll throw into the mix is shoulders. After holding Warrior 2 for 10(plus) deep breaths, you'll also start to feel your shoulders work.

Getting into this position is fairly easy for anyone. Take a step between three and four feet apart. Raise your arms so they're parallel with the ground - reach for the sides. Turn your back foot out at a 90 degree angle, and bend your front leg so your knee comes just over your toes. Keep your abdominals engaged, upper body straight (not leaning forward) and try not to let your hips rotate to the front leg.  Hold for 30 to 60 seconds. Switch sides.

Wall Squat
If you're a regular to this blog, then you've seen the wall squat appear on more than one occasion. Personally, I like to do wall squats after I finish a run, bike ride, or something that "pre-fatigues" my legs. Going into this exercise after you're well warmed up, but not totally cashed, will activate the quadriceps and glutes right away. It doesn't look like much. Anyone can "sit." But when you're propped against a wall and don't have anything to sit on, things become more difficult.

Lean against a walk with your feet about hip-width apart and 12 inches out from the wall. Drop down into a seated position. If your knees are extending over your toes, walk your feet out until they’re in line with one another. Don’t let your knees collapse in together. Hold for 30 to 60 seconds. Repeat 3 times.

Straight Arm Plank
There are a lot of good core exercises that go well beyond the realm of crunches. A great core exercise will work not just the abdominals, but also the lower back. This is why I love planks. It's a great barometer of your own core strength. The second you start feeling discomfort in your low back, it's time to take a rest. Hopefully, as you continue to work your core, that feeling of discomfort in the back becomes more and more distant.

Drop down onto your hands and knees. Straighten legs, and push your body into a push up position. Hold with your arms straight - don't come down - and you're doing a straight arm plank. Press into the palms of your hands. Pull your belly button into your spine and keep your hips high enough to prevent any sort of sway in your lower back. Sounds easy enough, right? Now hold for 30 to 90 seconds. If you're a 'core master,' hold for two minutes!