Fig. 1.

Examples of fiber type proportions in a prediabetic man undergoing 16 wk of resistance training. Images displayed show examples of a single subject’s fiber type proportions in 3 separate biopsies. The proportions were determined by counting ≥200 transverse-cut fibers for each biopsy, usually 3 or more sections (see methods). This individual was calculated to have 29, 40, and 47% type IIx fibers at 0, 8, and 16 wk of training, respectively. In these images, type I fibers appear dark, type IIx fibers are red, and type IIa fibers appear intermediate or purple. The white bar shown in pretraining image (left) represents 100 µm.