Thin filaments attached to Z lines, which slide toward actin during contraction. The Myosin, which are thick filaments bind to actin and pull. The Z lines mark boundaries of each sarcomere, I band contains actin without overlapping Myosin. H zone is central zone containing Myosin and M line is center of sarcomere. Myosin Attaches to actin, pull towards center, z lines mover closer, I amd H zones become smaller while A lines remain same shape, Both Actin and Myosin slide past each other.