In order to stretch the erector spinae, exercises focusing on forward bends are recommended by the Houston Chronicle. Stretches that move the knee away from the front of the pelvis effectively increase the mobility of the hip flexors, adds FitBodyHQ.
The erector spinae is a collection of muscles and tendons that run vertically down the length of the spine and aid in keeping the upper body upright, bending sideways and twisting, reports the Houston Chronicle. Cat pose is recommended as a warm-up to more rigorous stretches. In this pose, the individual is on all fours and the spine first arches up like a cat and then bends the opposite way towards the ground. After this stretch, toe touches should be attempted. Side bends are then used, stretching one side and then the other from a standing position. A twisting stretch may also be attempted from a supine position, where the right hand pulls the left knee across the body and vice versa.
To stretch the hip flexors, a butterfly stretch may be first used to open up and activate the hip joint, according to FitBodyHQ. The individual may then get into a lunging position but drop their back knee to the ground. By leaning backwards with the knee planted to the ground, a stretch is felt down the front of the hip and leg. The back foot may also be raised and held for a deeper stretch of the hip flexor.