Background: A pressure ulcer (PU) is a localized injury to the skin or underlying tissue usually over a bony prominence. The prevention PU per patient per day is costly; therefore, the detection of a PU at its earliest stage is imperative to afford timely interventions. Currently, there are very few clinically useful tools to assist with early PU detection and prevention. Aim: There were two primary aims of this study: (1) to investigate the relationship between activity, mobility, and PU development; and (2) to ascertain the next steps for delineating an algorithm based on activity and mobility for detecting PU risk among older adult residents in long-term care. Method: This quantitative, prospective, descriptive, non-experimental study was conducted between July 2019 and March 2020 among 53 older adult residents who were followed for 4 consecutive days. Participants’ Braden score, Elderly Mobility Scale (EMS) score, Movement Level, and 6-item Cognitive Impairment Test score were assessed. Further, the sacrum and heels were assessed daily using a non-invasive subepidermal moisture (SEM) scanner and visual skin assessment (VSA). SEM values > 0.5 were considered as indicative of the presence of an SEM-PU. Results: The incidence rate of VSA-PU was 15.1% (N = 8). There was an incidence of 87.5% (N = 42) of SEM-PU damage. According to the Braden subscale, Mobility Braden, most of the participants (62.2%, N = 33) were assessed as having no limitations/slightly limited mobility, while the EMS indicated that most of the participants (67.9%, N = 36) were classed in an independent category. From the 42 SEM-PUs observed, 62% (N = 26) occurred among the low movers, and 38% (N = 16) occurred among the high movers. Linking Evidence to Action: Using traditional methods for the assessment of movement does not provide insight into the protective nature of the movement. Given that both low- and high-moving patients can develop tissue damage, it is important to focus on the assessment of movement using more objective measures and algorithms, which enable real-time assessment of the protective nature of the movement. This would enable development of person-centered PU prevention strategies to reduce the burden of this significant healthcare problem.