Benefits and Uses
Warrior I is a strengthening, stretching, and even a bit of a balancing pose, that can inspire confidence and power in its practitioner. The standing pose strengthens the muscles of the legs, arms, shoulders, and back while stretching the calves, upper body, and psoas (groin area). Practice Warrior I after warming up your body, during the higher intensity portion of your yoga workout.   

Directions
Begin by standing at the front of your mat in the mountain pose. Step or slide your right foot behind you until it is about 3 feet from your left (front) foot. Place your right (back) heel on the floor and angle the toes so that they point toward the front right corner of your mat. Imagine a line intersecting your heels for a balance-challenging alignment, or for more stability separate your feet wider so that they no longer intersect. Using strength, bend your left (front) leg to create a 90-degree angle between your calf and thigh, so that your knee is in line with your ankle. If this is too intense or your balance feels unstable, lessen the bend in your knee. Place your hands on your hips and reach your right hip forward, squaring your hips with the front edge of your mat. Next, reach your arms energetically toward the ceiling, palms facing one another. Picture your tailbone dropping down and tucking slightly so that you are not crunching in the lower back. Create space in your chest and back as you breathe deeply into the pose and reach away from your center. Ground your feet into the earth and engage your core as you become strong and steady in the pose. Repeat with the left leg in front or incorporate other poses into your sequence before switching sides.   

• Breath: Deep and steady breathing (using ujjayi breath if possible) will help you to relax during this challenging pose. Observe your breath when you come into the pose and notice if it becomes shallow or non-existent as you hold the pose for a few moments. When you breathe fully and consciously how does this affect your experience of the pose? 
• Modifications: This pose is excellent for pregnant women during the first and second trimesters to help build leg strength to support the growing baby. During the third trimester, the pose is likely to become more challenging as your body’s sense of balance changes (in part due to the hormone relaxin. To receive similar benefits with less intensity, place a chair sideways under your front (bent) leg in order to support your weight (you may have to play around with chair size and placement to maximize comfort). Try to maintain the alignment in the rest of the body despite using this support. 
  
  For a higher intensity, energetically reach your back heel up towards the sky so only your toes are on the floor (instead of the angled back foot). Feel the effects of this challenging modification.  
• Release: Stay in this pose for 30 seconds to 1 minute while breathing deeply and calmly. Release by straightening the front leg, walking your feet back together, and feeling the effects in the mountain pose (or moving on to another posture). Release as soon as necessary if at any point you feel pain or discomfort. 

Go on: Warrior II (Virabhadrasana II)