Note that this reference documentation is identical to the help that is displayed in MATLAB when you type “help ft_artifact_muscle”.

  FT_ARTIFACT_MUSCLE reads the data segments of interest from file and
  identifies muscle artifacts.
  Use as
    [cfg, artifact] = ft_artifact_muscle(cfg)
  with the configuration options
    cfg.dataset     = string with the filename
    cfg.headerfile  = string with the filename
    cfg.datafile    = string with the filename
  Alternatively you can use it as
    [cfg, artifact] = ft_artifact_muscle(cfg, data)
  In both cases the configuration should also contain
    cfg.trl        = structure that defines the data segments of interest. See FT_DEFINETRIAL
    cfg.continuous = 'yes' or 'no' whether the file contains continuous data
  The data is preprocessed (again) with the following configuration parameters,
  which are optimal for identifying muscle artifacts.
    cfg.artfctdef.muscle.bpfilter    = 'yes'
    cfg.artfctdef.muscle.bpfreq      = [110 140]
    cfg.artfctdef.muscle.bpfiltord   = 8
    cfg.artfctdef.muscle.bpfilttype  = 'but'
    cfg.artfctdef.muscle.hilbert     = 'yes'
    cfg.artfctdef.muscle.boxcar      = 0.2
  Artifacts are identified by means of thresholding the z-transformed value
  of the preprocessed data.     = Nx1 cell-array with selection of channels, see FT_CHANNELSELECTION for details
    cfg.artfctdef.muscle.cutoff      = z-value at which to threshold (default = 4)
    cfg.artfctdef.muscle.trlpadding  = 0.1
    cfg.artfctdef.muscle.fltpadding  = 0.1
    cfg.artfctdef.muscle.artpadding  = 0.1
  The output argument "artifact" is a Nx2 matrix comparable to the
  "trl" matrix of FT_DEFINETRIAL. The first column of which specifying the
  beginsamples of an artifact period, the second column contains the
  endsamples of the artifactperiods.
  To facilitate data-handling and distributed computing you can use
    cfg.inputfile   =  ...
  If you specify this option the input data will be read from a *.mat
  file on disk. This mat files should contain only a single variable named 'data',
  corresponding to the input structure.