Normalized mean OD of SDH and GPDH activities and their relationships to the fibre types. A, B: OD standardised to Z scores of SDH and GPDH activities of the MyHC-based fibre types. Mean OD for SDH and GPDH (A). SDH:GPDH ratio (B). Values are pooled means of the 814 fibres analysed in the two skeletal muscles (PM and FD). Vertical bars represent the 0.95 confidence intervals. C, D: Fibre-to-fibre relationships between OD of the immunostaining and SDH and GPDH histochemical activities in various subsets of hybrid fibres. Relationship between the S58H2 MAb (anti MyHC I and IIX) and both SDH and GPDH staining of all I+IIA hybrid fibres identified in the present study (n = 42 fibres) (C). Relationship between the BF35 MAb (anti MyHC I and IIA) and both SDH and GPDH staining of all IIAX hybrid fibres identified in the study (n = 59 fibres) (D). r: Pearson coefficient of correlation; #, *: p < 0.001 and p < 0.05 levels of significance, respectively.