Fig. 5

Contractile measurements of single muscle fiber from P1 (33 years old) and controls. A A trend towards decreased absolute force in type 1 muscle fibers of P1 (1 biopsy, n = 12 fibers) compared to controls (6 biopsies, n = 7–14 fibers/biopsy). B Significant decrease in CSA in type 1 muscle fibers of P1 (1 biopsy, n = 12 fibers) compared to controls (6 biopsies, n = 7–14 fibers/biopsy). C No significant difference in maximal normalized force in type 1 muscle fibers between P1 (1 biopsy, n = 12 fibers) and controls (6 biopsies, n = 7–14 fibers/biopsy). D Force-pCa curve of P1 (1 biopsy, n = 12 fibers) shows a leftward shift compared to controls (6 biopsies, n = 7–14 fibers/biopsy). E Significant increase in pCa50 in type 1 muscle fibers of P1 (1 biopsy, n = 12 fibers) compared control (6 biopsies, n = 7–14 fibers/biopsy). F No significant difference in passive stiffness of type 1 muscle between P1 (1 biopsy, n = 9 fibers) and controls (3 biopsies, 2–9 fibers/biopsy) at 3 different sarcomere lengths. The data are presented as mean ± SD. Statistical analysis performed by linear mixed model and Wald chisquare test, *p < 0.05, **p < 0.01