In 2010, Frank Sanders and Kenneth Carpenter published a study concluding that Robinson's model had been correct. Frey & Riess would have been mistaken in their assertion that the shoulder and pelvic plates had no muscles attached to their upper sides. While these muscle groups were probably not very powerful, this could easily have been compensated by the large muscles on the back, especially the "Musculus latissimus dorsi", which would have been well developed in view of the high spines on the backbone. Furthermore, the flat build of the shoulder and hip joints strongly indicated that the main movement was vertical, not horizontal.