Effects of Velocity-Based Resistance Training on Renal Function and Metabolic Health in Kidney Transplant Recipients: Protocol for a Pilot Randomized Controlled Trial.

backgroundKidney transplant recipients present reduced physical function and a high prevalence of cardiometabolic complications, which increase cardiovascular risk and compromise long-term graft outcomes. Resistance training has demonstrated beneficial effects in this population; however, previous interventions have shown heterogeneity in load prescription and have not incorporated objective monitoring of movement velocity. Velocity-based resistance training (VBT) allows precise regulation of exercise intensity and fatigue, potentially improving the safety and individualization of exercise prescription in clinical populations.

objectiveThis study aims to evaluate the effects of a 12-week VBT program on renal function and metabolic health in kidney transplant recipients and to compare 2 different load-control strategies based on movement velocity.

methodsThis pilot randomized controlled trial will include adult kidney transplant recipients with stable graft function. Participants will be randomly assigned (1:1) to either a maximal velocity group, in which sets will be terminated at a 20% velocity loss threshold, or a constant submaximal velocity group, in which participants will perform repetitions at 50% of the participant's individual maximal velocity. Both groups will complete 3 supervised training sessions per week for 12 weeks with real-time velocity monitoring. Primary outcomes will include renal and metabolic health domains assessed through venous blood analysis. Serum creatinine will be the prespecified hierarchical primary renal end point, and high-density lipoprotein cholesterol will be the prespecified hierarchical primary metabolic end point. Estimated glomerular filtration rate will be calculated using the Chronic Kidney Disease Epidemiology Collaboration equation. Secondary outcomes will include blood pressure, body composition, muscular strength, metabolic syndrome criteria, and the force-velocity profile. Data will be analyzed using analysis of covariance and linear mixed-effects models following a predefined hierarchical inferential strategy.

resultsThe study was initiated in September 2025. Participant recruitment and the intervention phase have been completed. All 14 participants completed the 12-week training program, and no participants were lost to follow-up. Preintervention and postintervention data collection has been completed according to the study protocol. The study database has been cleaned and locked, and statistical analyses are currently underway. Publication of the primary study results is anticipated in late 2026.

conclusionsThis study introduces the implementation of VBT in kidney transplant recipients. The findings are expected to provide evidence on the feasibility and potential benefits of this approach and may support the integration of exercise professionals into multidisciplinary transplant care teams.

trial registrationClinicalTrials.gov NCT07370727; https://clinicaltrials.gov/study/NCT07370727. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/94010.