Figure 7. Effect of muscle activation on the length changes of the shared distal portion of the Achilles tendon.

Changes in Achilles tendon length (ΔL_AT) in response to simultaneous contraction of GA+SO (Δ), and to individual contraction of SO (•) and GA (▪) are plotted as a function of sagittal plane ankle angle. Knee angle was kept constant at 90°. Effects of ankle angle were found for SO, GA and GA+SO (p<0.001). Length changes due to SO contraction were lower than length changes due to GA (p = 0.033) and GA+SO (p = 0.028) contraction. No differences were found between GA and GA+SO contractions (p = 1.000). Means ± s.d. are shown (n = 10).