You wouldn't leave your laces untied so don't tax your muscles without a little preparation. These three yoga poses done before you run will help you find your best stride.

For all hip, knee and low back tension try Pigeon

From downward facing dog bring the right knee between the hands and place the right ankle as close to the left wrist as possible. Extend the left leg backward, ensuring the leg is in line with the hip and the kneecap faces the floor. Come up onto the fingertips, inhale lifting the pelvis up and lengthening the front of the torso as well as flattening out the curve of the low back, sending the tailbone down. Arching the upper chest slightly fold forward over the front leg. Releasing all the tension in the back, neck and shoulders rest your forehead on your knee, or on your forearms. Balance the weight equally in the right and left hip, drawing the right hip back as the front of the left thigh lengthens. Stay in this pose for 10 to 15 breaths. To come up, place both hands flat on the ground beneath the shoulder blades. Draw the right knee into your chest as you float back to downward facing dog. Take four breaths feeling the differences between the right and left sides of the body. Repeat on the other side.

For the best overall leg, shoulder and back stretch try Fan with Hands Interlaced

Separate the legs 4 1/2 feet apart. Be sure the weight is equally distributed into both sides of the feet. Turn the toes slightly in to stretch the outer ankle. Feel the thighs rotate outward and the kneecaps drawing up into the quads. Interlace the hands behind your back, drawing the shoulders as far down the back as possible. Inhale and fold over until your spine is parallel to the floor, letting your head drop. As you exhale feel the knuckles draw toward the sky. Keeping the legs straight, stretching the back of the legs, hips and back and fold-from the waist- as far forward as you can without rounding the back. Find a slight arch in the upper back, keeping the sternum lifted as you fold forward. Stabilize the body with the large leg muscles allowing the back to release and the backs of the legs to lengthen. Hold for 10 breaths. To come up engage your abdomen and draw the body up with a flat back.  Repeat once.

To get the legs, hips and low back loose try Low Lunge Variation

From downward facing dog step your right foot between your hands. Place the left knee down. Keeping the right knee over the ankle-and therefore scooting the left leg back if necessary--Bring both hands to the inside of your right foot. Align your right shoulder with your left knee. You should begin to feel a deep release in the hips, inner thigh and back. Let your head just hang. Drop down onto your forearms and allow your body weight to drop deeper into the hips. For a more athletic version life the back knee and straighten the leg. Hold for 1 to 3 minutes, step back into downward facing dog for four breaths and repeat on the other side.