Effects of Knee Savers on the quadriceps muscle activation across deep knee bending postures

Abstract

Workers who kneel or squat frequently are at a high risk of developing knee pathologies. Knee Savers® are wedge-shaped pads, worn on the lower calf by baseball catchers that aim to reduce this risk. This study examined how Knee Savers® change the bilateral quadriceps muscle activity during dorsiflexed kneeling, and heels-up and flat-foot squatting. For twenty participants, integrated and peak electromyography (EMG) during descent and ascent phases, mean EMG during a 10-s static phase, and participants’ subjective perception of muscle fatigue were compared between equipment conditions (with (W) and without (WO) Knee Savers®). Knee Savers® did not significantly reduce integrated or peak EMG during transitions into and out of the postures; however, they significantly reduced (p < .03) mean EMG in five of six muscles during the static phase. These findings indicate potential for Knee Savers® to reduce cumulative muscular effort and fatigue in applications where prolonged static kneeling or squatting are required.