Axioskop 2 mot plus stage

Capillaries were detected and analysed as described (van Ginkel et al., 2015b (link)). In brief, pre-exercise biopsies were mounted, and 14-μm thick cryosections prepared at a cutting angle perpendicular to the major axis of muscle fibers. Capillaries were detected based on a lectin antibody, and the section was recorded at a ×10 magnification with an Axiocam MRC camera operated by an Axioskop 2 mot plus stage (Carl Zeiss, Oberkochen, Germany). Areas of the section corresponding to 0.15 mm² where fibers were cut perpendicular and where no holes or other irregularities were present were selected. The areas were processed with the ImageJ software (version 1.6.0_33; http://imagej.nih.gov/ij) according to the published settings (van Ginkel et al., 2015b (link)) to determine the number of capillaries per mm² (capillary density) and the capillary-to-fiber ratio. Additionally, the mean cross-sectional area (MCSA) of slow (type I) and fast (type II) muscle fibers was determined on muscle cross-sections being stained with myosin isoform-specific antibodies as described (Vaughan et al., 2016 (link)). The values of at least 24 representative fibers per subject were analysed.

Capillaries were detected and analysed essentially as described [27 (link)]. In brief, pre-exercise biopsies were mounted, and cryosections prepared at 14-μm thickness under a cutting angle being perpendicular to the major axis of muscle fibres. Capillaries were detected based on a lectin antibody and the section recorded at a 10x magnification with an Axiocam MRc camera being operated by a Axioskop 2 mot plus stage (Carl Zeiss, Oberkochen, Germany). Areas of the section corresponding to 0.15 mm² where fibres were cut perpendicular and where no holes or other irregularities were present were selected. The areas were processed with the Image J 1.6.0_33 J software (http://imagej.nih.gov/ij) according to the published settings [27 (link)] to determine the number of capillaries per square millimetre (capillary density) and the capillary-to-fibre ratio. The values of at least 24 representative fibres per subject were analysed.