Author(s): TAKITO, M., NERI, L., FRANCHINI, I., PRADO, R., SILVEIRA, R., Institution: SCHOOL OF PHYSICAL EDUCATION AND SPORT OF UNIVERSITY OF SAO PAULO, Country: BRAZIL, Abstract-ID: 1272

Introduction
Social isolation during the Covid-19 pandemic has required resilience to adhere to healthy habits, including physical activity levels. This study aimed to assess changes in physical activity adherence during this period, focusing on biological, psychological, and social factors.

Methods
This cross-sectional study included 3,898 adults (n=2,289 physically active; n=1,609 insufficiently active). Participants completed an online survey assessing self-reported data on anthropometric and socioeconomic variables (sex, age, body mass index [BMI], educational attainment, and fear of COVID-19 effects) and exercise-related behaviors before (Transtheoretical Model of Behavioral Change [TTM], and Physical Activity Enjoyment Scale [PACES] for prior exercise experiences) and during social isolation (beliefs regarding attitude, subjective norm, and perceived control), including physical activity levels in both periods. Statistical analyses compared physically active and insufficiently active groups, while a Multilayer Perceptron algorithm identified the most relevant characteristics for significant comparisons in each group.

Results
Overall, the sample showed a significant decrease in physical activity levels from before to during social isolation (p < 0.001 for duration, frequency, and intensity). Except for BMI, the insufficiently active group showed worse values in all variables (p < 0.05). The Multilayer Perceptron algorithm ranked the most important characteristics as: 1st) Lower perceived control beliefs, a lower percentage of subjects in the maintenance stage of the TTM, and lower scores on process change; 2nd) Lower educational attainment, a higher rate of subjects exhibiting fear of the effects of COVID-19, and a higher proportion of women; 3rd) Lower attitude beliefs, younger age, lower enjoyment from exercise experiences, lower self-efficacy, lower decisional balance, and lower subjective norm beliefs. The insufficiently active group exhibited greater fluctuation in their physical activity behaviors, while the physically active group showed opposite characteristics during the isolation period.

Discussion
Social isolation measures during the COVID-19 pandemic significantly reduced physical activity levels in Brazil. Individuals with lower self-efficacy and inconsistent exercise routines were more likely to experience a decline in activity levels. To improve adherence, interventions should target individuals who struggle to maintain physical activity, focusing on perceived control, self-efficacy, and exercise enjoyment. Exercise professionals should enhance these psychological characteristics and provide ongoing support to help individuals sustain physical activity during challenging periods like social isolation. These characteristics reflect the need for resilience to maintain exercise routines in adverse situations, such as the pandemic.