Eccentric Cycling Improves Cardiopulmonary Fitness, Respiratory Function, and Quality of Life in Chronic Kidney Disease: A Randomized Controlled Trial

Objective To compare the effects of eccentric cycling (ECC), concentric cycling (CON), and standard care (CTL) on cardiopulmonary capacity, respiratory health, and quality of life (QoL) in patients with chronic kidney disease (CKD). Methods Thirty-one CKD patients were divided into the CTL, CON, and ECC groups. The CON and ECC groups participated in 8-week, 24-session cycling programs. Outcomes were assessed through cardiopulmonary exercise tests, respiratory function tests, and the 36-Item Short Form Survey Instrument questionnaire. Results The ECC group achieved significant improvements in maximal oxygen uptake, while the CTL group showed a decline. For oxygen uptake efficiency slope, significant changes were observed only in the ECC group, with a group-by-time interaction effect compared to CTL. Furthermore, the ECC group demonstrated the most significant increase in diaphragm movement and a significant increase in diaphragm thickness, with comparisons indicating that ECC outperformed both CTL and CON. Regarding QoL, the ECC group exhibited significantly greater improvements in Physical Component Summary and Mental Component Summary, with statistically significant differences compared with the CTL and CON groups. Conclusion ECC is a low-effort, high-benefit exercise modality that significantly enhances cardiopulmonary fitness, respiratory function, and QoL in patients with CKD.