Figure 2.

Fascicle length and fascicle pennation angle data from a single subject. (A) With the ankle at 90°, muscle fascicles in the lateral gastrocnemius (LG, red lines) started at a longer length compared to fascicles in the medial gastrocnemius (MG, black lines). All fascicles shortened during the ramped isometric contraction. (C) The magnitude of this shortening varied between 0.2 and 4.5 mm across fascicles; the trimmed means for MG and LG fascicles are presented as bold lines. (E) When expressed as a percentage of the initial length of each fascicle, this corresponded to a shortening of 0.5–9.5%; trimmed means are also presented. MG and LG fascicles shortened to a greater extent when the ankle was at 120° (B, D, F; note the difference in x‐axis range). On completion of the ramped contractions, fascicle shortening was greater in MG compared to LG in this subject. (G) With the ankle at 90°, LG fascicle pennation angles were generally smaller than those of MG fascicles. (I) All but one fascicle had a decrease in pennation angle over the course of the ramped contractions. On average, pennation angle decreased 0.8–1.0°. With the ankle at 120° (H, J), LG fascicle pennation angle increased ~2.5° whereas, on average, there was no change in MG fascicles.