Background Coronavirus disease has provoked much discussion since its first appearance. Despite it being widely studied all over the world, little is known about the impact of the disease on functional ability related to performing activities of daily living (ADL) in patients post COVID-19 infection. Objectives To understand the impact of COVID-19 on ADL performance of adult patients and to describe the common scales used to assess performance of ADL on patients post-COVID-19. Methods A systematic review was conducted. We included studies that applied a physical capacity test in COVID-19 patients, post-infection. Two independent reviewers analyzed the studies, extracted the data, and assessed the quality of the evidence. Results A total of 1,228 studies were included, after removing duplicates, 1,005 abstracts were screened and of those 983 were excluded. A final number of nine studies which met the eligibility criteria were included. The findings revealed worsening of physical function and ADL performance in all patients post COVID-19 infection. Conclusion All included studies found a reduction of ADL beyond the test or scale used, revealing a vital worsening of functional ability in ADL performance and consequently loss of independence in COVID-19 patients after the acute phase of infection. Functional ability status previous to COVID-19 is crucial for predicting the severity of the disease and mortality. Barthel Index and ADL score were the most used assessment tools across subjects with different intrinsic capacity and context levels.