A body limb movement limiter restrains the movement of a person's arm so as to protect the person's shoulder or restrains the movement of a person's lower leg with respect to the upper leg so as to protect the person's knee. The device uses a housing having a reel disposed therein with a tether attached thereto and a shear thickening non-Newtonian fluid disposed within the housing so that the fluid acts on the reel during a payout procedure of the tether. The housing is attached to a strap secured about the torso of the person while the free end of the tether is secured about the person's arm. Alternately, a pair of arms are pivotally secured to each other within a housing having the non-Newtonian fluid therein for limiting movement of one arm with respect to the other.