Come to all fours. Check that your wrists are directly underneath your shoulders and that your hips are right above your knees. Toes point straight back. Look down at the mat to lengthen the back of your neck.
Inhale, press your right foot back and extend your left arm forward—palm facing in. Exhale, relax into the pose.
Check that your back leg is no higher than hip height, flex your back foot and point your toes straight down.
Draw your abs in and try to keep your lower back level.
Hold for 3-5 breaths on each side.
You can bring your knee to touch your nose 3-4 times to work the core and improve spinal mobility.