A star does not rotate as a solid body. The outer parts of a star contribute most to a star's quadrupole moment. Applegate proposed that as a star goes through its activity cycle, magnetic torques could cause a redistribution of angular momentum within a star. As a result, the rotational oblateness of the star will change, and this change would ultimately result in changing the orbital period via the Matese and Whitmire mechanism. Energy budget calculations indicate that the active star typically should be variable at the ΔL/L ≈ 0.1 level and should be differentially rotating at the ΔΩ/Ω ≈ 0.01 level.