Single muscle fiber force measurements of muscle fibers cultured in 2D and 3D systems on days 1 and 7 of culture. (A) Graphical overview of the force measurement experiment (image made in BioRender). (B) Quantification of the maximum force production of skinned muscle fibers at days 1 and 7 cultured in 2D and 3D. (C) Quantification of muscle fiber CSA at days 1 and 7 cultured in 2D and 3D. (D) Quantification of the normalized maximum force to CSA at days 1 and 7 cultured in 2D and 3D. (E) Quantification of single fiber rate of tension redevelopment (k_tr) at days 1 and 7 cultured in 2D and 3D. (F) Example SDS-PAGE gel performed to analyze myosin heavy chain composition of pooled muscle fibers at days 1 and 7 cultured in 2D and 3D. (G) Quantification of relative myosin heavy chain abundance in pooled muscle fibers at days 1 and 7 cultured in 2D and 3D. Data are means ± SEM; large dots represent mean values per mouse, and small dots represent single muscle fibers. Significance was determined using the two-way ANOVA test in panels B–E and using χ-square test in panel G with P < 0.05 considered as significant with * = P < 0.05 and ** = P < 0.01. Source data are available for this figure: SourceData F3.