## 1 Introduction  
The world's population is aging rapidly. According to the United Nations [1], by 2050, one in six people will be over the age of 65 years globally, triple the number of 2019. This demographic shift comes with substantial health and economic challenges, as aging is associated with an increased risk for chronic diseases, like heart disease, diabetes,osteoporosis, arthritis, and sarcopenia [2; 3; 4]. Age-related losses of muscle mass, strength, and function, also known as sarcopenia, negatively impact the quality of life and ability to live independently [5]. Thus, identifying strategies to mitigate sarcopenia and its related consequences is an urgent public health priority.  
Exercise participation helps to prevent and manage age-related decline, like sarcopenia, osteoporosis, and loss of balance, in older adults [6; 7; 8; 9]. While the benefits of dancing are promising, understanding its specific workload implications is crucial for prescribing it safely and effectively. Recent systematic reviews have explored the risks and benefits of other physical activities, like judo [10; 11] and sport participation [12], in older populations. [PERSON] et al. [10] found that appropriately dosed judo training can improve muscle strength, flexibility, and fall prevention in middle-aged and older adults, though the risk of injury must be carefully managed. [PERSON] et al. [11] reported judo's dynamic throwing and grappling movements provide osteogenic benefits. [PERSON] et al. [12] concluded in their meta-analysis that sport participation reduces the risk of falls and functional limitations, while enhancing the quality of life in older adults. Like these activities, dancing integrates physical challenges within a socially enriching context that appeals to older exercisers [13; 14]. Researchers have demonstrated that dancing produces various benefits among older people, such as better balance, gait, endurance, strength, and quality of life, compared to non-dancing controls [15; 16; 17].  
While the benefits of dancing for older adults are promising, few studies have quantified the specific external loads that older dancers experience to guide programing. Evaluating a dance's workload profile can shed light on its safety and potential to mitigate age-related musculoskeletal decline. Wearable inertial measurement units (IMUs) enable the objective quantification of external loads via the impacts accumulated [18]. High volumes of repeated impact may fatigue structures and heighten injury risks [19]. Thus, monitoring the musculoskeletal load distribution can inform guidelines for safe, sustainable dance programing for older adults [20]. Factors like music and fatigue across a dance session can influence impact accumulation, though this has not been explored in older dancers.  
Therefore, this study aimed to: (1) characterize the external workload experienced by older people across various anatomical locations during a 60 min Latin dance class and (2) examine whether factors like music genre and session duration influence the workload. We hypothesized the participants would accumulate the greatest workload at the ankle, followed by the knee, lumbar region, and scapulae. We also predicted faster, more rhythmic genres would elicit higher impacts than slower songs and that fatigue would provoke decreased impacts from the first to the last songs. The findings from this study can guide the prescription of safe, optimal dance programing for older adults, while shedding light on how music genre and fatigue may modulate the external dance workload. With global aging rising, this work addresses a timely public health need regarding sustainable lifelong exercise.