<p>The purpose of this study was to examine the impact of the type of treadmill translation on the stance limb medial gastrocnemius (MG) spatial muscle activity during standing perturbations. Ten healthy young adults experienced three types of standing perturbations (300 ms duration) on a split-belt treadmill: <i>unilateral backward translation</i> of the left treadmill belt, <i>unilateral forward translation</i> of the left treadmill belt, and <i>bilateral backward translation</i> of both treadmill belts. The perturbation intensity was set for each participant and perturbation type as the maximal treadmill velocity that did not require the participant to take a step. A high-density 64-channel surface electromyography (HDsEMG) grid was placed over the right MG. HDsEMG amplitude of the initial burst (70-300ms) during the perturbation and the second burst (300-600ms) immediately after perturbation stopped, the barycenter coordinates, and area of MG activation were calculated. Twenty-two retroreflective markers were used to describe the kinematic responses to the different perturbation types. MG amplitude showed no significant differences from baseline in either burst for Unilateral Forward Translations (<i>p</i> = 0.67–0.99) and was highest in unilateral backward translations (second burst; <i>p</i> &lt; 0.001). Unilateral forward translations resulted in more trunk extension, knee flexion, and ankle plantarflexion, than unilateral backward translations. In unilateral forward translations, the barycenter of HDsEMG was positioned significantly more proximally and laterally than in both backward translation conditions (<i>p</i> &lt; 0.0001). These findings underscore the influence of the type of treadmill translation on the medial gastrocnemius muscle activity, highlighting adaptive strategies in the stance leg contingent upon the direction of perturbation.</p>