Foot orientation affects muscle activation levels of ankle stabilizers in a single-legged balance board protocol

•Specific muscle activation can be targeted by foot orientation on the balance board.•Muscle modulation is similarly affected by foot orientation as muscle activation.•Peroneus longus is more activated exercising along a frontal then a subtalar axis.•Muscle coactivation patterns might be better controlled on a uniaxial balance board. The main goal of balance training is regaining a normal neuromuscular control to a functional level. Although uniaxial balance boards are commonly used, no research has been done on the effect of foot orientation on muscle activation levels. To investigate the effect of foot orientation on muscle activation levels and modulation of the ankle stabilizing muscles in a single-legged balance protocol on a uniaxial balance board. Sixty-nine healthy subjects (age: 21.8±1.7years; mass: 67.5±11.9kg; body height: 174.7±8.6cm; BMI: 21.5±3.0) participated in this study. Subjects were asked to keep their balance during a single leg stance on a uniaxial balance board for four different foot orientations, aligning the board’s rotation axis with frontal, sagittal, diagonal and subtalar axes of the foot, respectively. Surface electromyography registered muscle activity of peroneus longus, tibialis anterior, medial and lateral gastrocnemius muscles. Highest muscle activation levels and modulation for the peroneus longus were registered exercising along the frontal axis; for the tibialis anterior along the diagonal axis; for the medial gastrocnemius along the sagittal axis; and for the lateral gastrocnemius along the diagonal axis. Foot orientation modifications on a uniaxial balance board allows to differentially target specific ankle stabilizing muscles during balance training.