Very good question!
I also noticed this very weird behaviour and couldn't find an explanation/solution for it.

Hey guys, referring to Steele at al. [Steele, Katherine M., et al. "Compressive tibiofemoral force during crouch gait." Gait & posture 35.4 (2012): 556-560.] it is possible to include different weights c_i for the muscles i in static optimization. Thus, the objective function becomes min{sum(c_i*(a_...