Over 20 million injuries result every year from motor vehicle collisions, with injuries to the neck being among the most prevalent. Muscle activity has been shown to affect head and neck kinematics significantly, especially in low‐speed collisions. The present study develops the framework to introduce strain‐ dependent muscle activation into a widely available computational human body model (HBM) and study the effects on head and neck kinematics. A single MAT_156 beam element from the Global Human Body Models Consortium (GHBMC) model in combination with a user‐defined subroutine to compute activation levels is used to model active force contributions of a full muscle. The model is validated against contraction velocities of experimental porcine tests, which are loaded with masses of 100−800 grams. CORA ratings between simulation and experimental results range from 0.538 to 0.810. Finally, we incorporate this strain‐dependent muscle activation scheme into the neck of the GHBMC for a low‐loading condition through a head fall test. Though the neck is too stiff when compared with volunteer data, simple modifications may be made to the model which results in closer agreement with experimental findings.