A variety of factors affect whether you'll have DOMS after a squatting exercise session, including the intensity of the exercise, the duration, whether you've warmed up your muscles before exercise, stretching and post-session recovery.
Many observers are of the opinion that a large precentage of software-related inventions are no longer patentable after the Supreme Court's explanation of the abstract idea exception. See BitLaw's discussion on whether software is still patentable after the Supreme Court's Alice Corp. decision and MPEP Section 2106.
From a patent perspective, mobile apps are no different from other software when it comes to patent eligibility and patentability, which means yes, apps can be patented. However, there are nuances to explore when looking at whether it makes sense to pursue a patent in a market in which a quick shelf life is the norm.