Reply to: Room for methodological improvement in gait speed study for COPD patients.

Competing Interests: Conflict of interest: J.A. Walsh has nothing to disclose. Conflict of interest: R.E. Barker has nothing to disclose. Conflict of interest: S.S.C. Kon has nothing to disclose. Conflict of interest: S.E. Jones has nothing to disclose. Conflict of interest: W. Banya has nothing to disclose. Conflict of interest: C.M. Nolan reports personal fees from Novartis, outside the submitted work. Conflict of interest: S. Patel has nothing to disclose. Conflict of interest: O. Polgar has nothing to disclose. Conflict of interest: B.M. Haselden has nothing to disclose. Conflict of interest: M.I. Polkey reports personal fees for consultancy from Philips and JFD, grants from GSK, outside the submitted work. Conflict of interest: P. Cullinan has nothing to disclose. Conflict of interest: W.D-C. Man reports grants from Medical Research Council UK, during the conduct of the study; grants from National Institute for Health Research, British Lung Foundation and Pfizer, personal fees from Jazz Pharmaceuticals, Mundipharma and Novartis, non-financial support from GSK, outside the submitted work.