Improving posture requires working on your flexibility, checking out your home & work stations for poor ergonomics, and a strength training program. Tight muscles affect our posture, so you will need to use the foam roll on these as well as stretch them out.
Tight Muscle List: The hamstrings, which actually comprise of three separate muscles: the Biceps Femoris, Semitendinosus and Semimembranosus.
Rectus femoris, one of the four quadriceps muscles, which inserts into the patellar tendon, which connects the kneecap (the patella) to the shin bone.
Tensor Fasciae Latae (TFL) on the outside of the thigh.
Piriformis, which is in the butt region.
Adductors, the inner thigh muscles.
Gastrocnemius, the muscle in the back part of the lower leg running from just above the knee to the heel.
Quadratus lumborum, one of the muscles of the low back, a primary cause of lower back pain.