Boat pose (navasana) is a classic pose. You can add a wide range of variations to keep it interesting, increasing or decreasing the challenge, or changing the muscles of focus. I recently focused on stretching the psoas, this pose can help strengthen the psoas one of the muscles that contributes to your core strength.
Start in a seated position with your feet on the floor.
Grab either the back of your thighs or shins. Gently pull with your hands, bending your elbows so you find a slightly longer spine.
Option 1: Lift your toes on the floor. You can keep holding on to your legs or let go for extra work.
Option 2: Lift your feet up to the height of your knees.
Option 3: Straighten your legs by lifting your feet up.
Option 4: Start with legs straight, then slowly let one foot lower down. You could touch the toes to the floor or not. Then switch sides. Change back and forth several times.
