Setup and Key Actions
Begin by standing in tadasana (mountain pose) with your feet parallel and four to six inches apart. Step your left foot back about one leg-length. Turn your back foot to point toward the upper left corner of your mat (about a 30- to 45-degree angle). If you feel unstable, as if you're standing on a tightrope, widen your stance by walking your right foot a bit more to the right. Imagine that your back foot is glued to the floor, but you're trying to turn it out anyway (to find a sense of external rotation in your back leg). At the same time, keep your back inner thigh rolling up. With your back leg solid and strong, turn from your belly to face the front short edge of your mat (don't worry about getting your hips 100 percent square—they probably won't be). Keep your front knee stacked over your heel and pointing straight ahead (err on the side of moving your right knee toward the pinky-toe side of your right foot, while keeping the ball of your right big toe rooted). Reach your arms up overhead, lifting your shoulder blades and rib cage along with your arms. Turn your pinkies toward each other slightly to broaden your upper shoulder blades, releasing tension in your neck and shoulders. Stretch out through your legs as if you’re trying to stretch your mat in two, and reach up through soft fingers.
If you're unable to keep your back heel grounded, lift your back heel and stack it directly over the ball of your foot (crescent lunge). Avoid lifting the heel with the toes turned out.
You can also practice warrior I with your front thigh supported on an angled chair seat.