Figure 6.

Normalized force enhancement as a function of (a) initial sarcomere length (the average sarcomere length of the myofibril prior to stretching) and (b,c) stretch amplitude. (a) Force enhancement was normalized relative to the maximal force enhancement observed in each of the 12 myofibrils. There is a small but statistically significant relationship (R²=0.20, p<0.05) between force enhancement and initial sarcomere length. (b) Normalized force enhancement as a function of sarcomere stretch magnitude for all sarcomeres from the 12 myofibril preparations. There was no statistically significant relationship between these two variables for the conditions of this test. (c) Force enhancement as a function of sarcomere stretch amplitude in a given myofibril, where the total stretch magnitude was small (12% of the initial sarcomere length). For this scenario, there is a positive correlation between sarcomere stretch and force enhancement (r²=0.98, p<0.05).