The present invention relates to a potency assay for skeletal muscle derived cells (SMDC), the potency assay comprises the steps of (a) measuring ACh E activity of SMDC, and (b) evaluating the potential of the SMDC to be used for the treatment of skeletal muscle dysfunction based on the AChE activity measured in step (a). Moreover, the present invention relates to skeletal muscle derived cells (SMDC) for use in the treatment of a muscle dysfunction. Finally, the present invention relates to the use of AChE activity as an in vitro differentiation marker for skeletal muscle derived cells and to a kit for performing the potency assay according to the present invention.
