Wenz T, Diaz F, Hernandez D, Moraes CT. Endurance exercise is protective for mice with mitochondrial myopathy. J Appl Physiol 106: 1712–1719, 2009. First published March 12, 2009; doi:10.1152/japplphysiol.91571.2008.—An investigation by the University of Cologne regarding the work of the first author, in accordance with the Guidelines for Safe-guarding Good Academic Practice and Dealing with Academic Misconduct of the University of Cologne, has determined that “serious scientific misconduct by way of data manipulation (according to §§6 1.a), b) GWP-O) and the violation of obligatory documentation requirements (according to § 1(1) GWP-O)” has occurred in this publication. Although the investigation report sent to the APS did not specify the errors in the article, the authors are aware that three Western blots in Figure 2C (ND39, SDH, and ATPβ in muscle mitochondria) were also published in an article in Cell Metabolism (DOI 10.1016/j.cmet.2009.04.010) to represent different experimental findings. Therefore, whether or not the main conclusions are still valid, the other authors request retraction of this publication because the scientific integrity of the study was compromised. The authors sincerely apologize to the scientific community.