Fig. 2. Myoelectric signals and intensity spectra from fast- and slow-twitch muscle fibres. Data are taken from one fish. EMGs were recorded from red muscle (mean fibre diameter 36 µm) during slow swimming (A) and from white muscle (mean fibre diameter 74 µm) during a fast-start (B). The boxes indicate the time regions for the red fibres (red box) and white fibres (blue box) analysed for frequency content. The intensity spectra for these regions (C) show a threefold increase in mean frequency, MF, between the red (red triangles) and white (blue circles) muscle fibre types. Spectra are normalized so that total intensity equals 1.
