One last piece of great news if you're feeling guilty about taking a break: Muscle memory actually makes it easier to regain strength than it was to build that muscle the first time Myonuclei acquired by overload exercise precede hypertrophy and are not lost on detraining . Bruusgaard JC, Johansen IB, Egner IM, Rana ZA, Gundersen K. Department of Molecular Biosciences, University of Oslo, 0371 Oslo, Norway. Proc Natl Acad Sci U S A. 2010 Aug 24;107(34):15111-6. Epub 2010 Aug 16 . So whether that gym membership expired, you got sick , or a dog ate those gym shoes (eww!), climb back up on that horse and keep on keeping on!