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. 2021 Dec 16;14(12):dmm049006. doi: 10.1242/dmm.049006

Fig. 5.

Fig. 5.

Characterization of the segmental rate of force development during contraction, segmental rate of force reduction during relaxation, real-time rate of force development during contraction and real-time rate of force reduction during relaxation in isometric tetanic contraction. (A) An illustrative tracing of the force development during tetanic contraction. The contraction phase refers to the time from the start of electric stimulation (gray dashed line) to the end of electric stimulation (gray solid line). The contraction phase is divided into ten segments (gray brackets). Each segment represents 10% of the force. (B) Average df/dt in every 10% increment of the Po during the contraction phase. (C) An illustrative tracing of the force during the relaxation phase of tetanic contraction. (D) Average −df/dt in every 10% reduction of the Po during relaxation. (E) Real-time tracing of the rate of force development during the contraction phase of tetanic contraction in the normal and dystrophic ECU muscle. gray, tracing from the individual ECU muscle; orange, tracing of the mean real-time rate of force development in the normal ECU muscle; blue, tracing of the mean real-time rate of force development in the dystrophic ECU muscle. The inset shows a diagrammatic illustration of the FWHM at contraction. (F) Quantitative comparison of FWHM at contraction. (G) Real-time tracing of the rate of force reduction during the relaxation phase of tetanic contraction in the normal and dystrophic ECU muscle. Gray, tracing from the individual ECU muscle; orange, tracing of the mean real-time rate of force reduction in the normal ECU muscle; blue, tracing of the mean real-time rate of force reduction in the dystrophic ECU muscle. The inset shows a diagrammatic illustration showing the FWHM at relaxation. (H) Quantitative comparison of FWHM at relaxation. Sample size: normal (n=15) and affected (n=15). Data are mean±s.d. *P<0.05 (statistical analysis was performed using multiple unpaired t-tests for B and D, and unpaired Student's t-test for F and H).