MoTrPAC DXA Quality Control

About This Grant

MoTrPAC DXA Supplement - Project Summary The Molecular Transducers of Physical Activity Consortium (MoTrPAC) is designed to discover and characterize the range of molecular transducers underlying the effects of exercise in humans. MoTrPAC was launched in 2016 with six adult clinical centers and a pediatric center that have collaborated to generate extensive Manual of Operations to guide research protocols involving all aspects of the clinical operations (Phase I). Phase II began in the fall of 2019 with all human clinical centers showing excellent progress towards initial recruitment goals and implementation of the protocol. The initial goal set forth by NIH was to recruit 270 children (10-17 years of age) and 1980 sedentary adults (age 18 years or greater) randomized to endurance training (170 youth, 840 adults), resistance training (840 adults), or non-exercise controls (50 youth, 300 adults). An additional group of highly active endurance (50 youth, 150 adults) and resistance (150 adults) trained individuals serve as comparators, not participating in the MoTrPAC exercise training programs. The recruitment and enrollment approach are sex-balanced, with participants across a wide range of ages (10-17, 18-39, 40-59 and >60-year age groups) and of different races. Due to the COVID-19 pandemic, beginning in March 2020, MoTrPAC activities were suspended for over a year with continued constraints through 2022. Despite the numerous challenges encountered as a result of the pandemic, the human clinical centers have successfully enrolled and completed the adult and pediatric highly active cohorts, the pediatric cross-sectional cohort, and the previously sedentary adult and low-active pediatric randomized control trial portion of the study as of May 2025. As data quality control is underway, discrepancies in dual-energy X-ray absorptiometry (DXA) data have been detected across different machines. This led NIAMS to provide MoTrPAC with funding to conduct additional DXA scans among previously enrolled MoTrPAC participants to develop a correction equation accounting for differences in DXA machines, allowing all MoTrPAC DXA data to be included in the final dataset. Altogether, this will allow MoTrPAC to complete the intended goals as originally envisioned, will provide a more complete public database of the health benefits of exercise, and will provide insight into how physical activity mitigates disease risk.