Abstract
BACKGROUND: Physical activity (PA) is crucial for maintaining bone mass. However, it remains unclear whether the "weekend warrior" (WW) pattern, namely condensing moderate-to-vigorous physical activity (MVPA) into 1 or 2 days per week, is beneficial for bone health. This study aimed to assess the association between the WW pattern and risk of low bone mass and related fractures.</p>
METHODS: We conducted a population-based study based on two nationwide databases, including 6972 participants aged 20-59 from the National Health and Nutrition Examination Survey (NHANES), 2007-2010 & 2013-2014 cycles, in which PA was self-reported via the Global Physical Activity Questionnaire; and 52,989 participants aged 37-60 years from UK Biobank (UKB), in which PA was measured by wrist-worn accelerometers over 7 days (2013-2015). In both surveys, lumbar spine and femoral neck bone mineral density (BMD) were assessed by dual-energy X-ray absorptiometry (DXA). Associations were analyzed using survey-weighted linear regression (in NHANES), multivariable linear regression (in UKB), and Cox proportional hazards models for incident fracture (in UKB).</p>
RESULTS: In NHANES, both the WW pattern and the regular active (RA) pattern were associated with higher femoral neck BMD compared with the inactive group (WW: β = 0.021, 95% CI 0.008-0.035, P = 0.004; RA: β = 0.015, 95% CI 0.007-0.023, P = 0.001), and both were associated with significantly lower odds of low bone mass. In UKB, similar favorable BMD associations were observed, and the WW pattern was associated with a lower hazard of incident fracture compared with both the inactive group (HR = 0.899, 95% CI 0.824-0.981, P = 0.017) and the RA group (HR = 0.897, 95% CI 0.823-0.976, P = 0.012).</p>
CONCLUSIONS: Meeting weekly PA guidelines is associated with favorable bone health indicators and lower fracture risk, regardless of whether activity is concentrated on weekends or distributed throughout the week. The WW pattern may serve as a time-efficient alternative for bone health maintenance.</p>