Warrior pose is an incredible yoga pose that helps build strength, stability, balance and endurance. It strengthens hip flexors and hamstrings of the back leg while stretching chest and shoulders - as well as building concentration and focus in our daily lives - helping us face challenges with determination and courage.
To enter warrior pose from Tadasana (mountain pose), step your left foot back at an angle of 45 degrees so it lines up with the center of the mat and your right foot should remain planted on the ground. Press through the outer edge of your back foot, ensuring that weight distribution between both feet remains equal. If this poses difficulty for your back knee, try bending it along with its front or move onto the ball of your foot for increased stability.
One misconception regarding front knee positioning is that it must be exactly parallel with the mat at 90 degrees; however, each body can find their own expression of this pose. Therefore it's better to bend your front knee as much as possible while keeping it aligned directly over your ankle.
From Warrior I, you can progress into Warrior III (Virabhadrasana II). Here, your right leg should be bent and planted on the floor with your torso while your left leg comes down parallel with it and hands interlaced above your head - choosing arm variations is up to you; however if your back shoulder ache becomes an issue consider keeping arms closer to ears for best results.