Stabilization in The Big Three: How Sensorimotor Feedback From Mechanoreceptors Influences Stabilizer Muscle Activity

Essay from the year 2025 in the subject Sport - Kinematics and Training Theory, grade: A, language: English, abstract: This study examined how sensorimotor feedback from mechanoreceptors influences stabilizer muscle activity during three fundamental weightlifting exercises: the squat, bench press, and deadlift. Mechanoreceptors (e.g. muscle spindles, tendon organs, joint receptors) provide proprioceptive input that can reflexively modulate muscle activation. I hypothesized that the closed-chain, axial loading of the squat and deadlift would elicit greater trunk stabilizer EMG than the bench press, which relies more on shoulder stabilizers. To test this, I propose using surface electromyography (EMG) to record stabilizer muscle activity in resistance-trained subjects performing each lift at matched intensity (e.g. 75% 1RM). EMG would be collected from key stabilizer muscles (lumbar erector spinae, multifidus, rectus abdominis, external oblique for squat/deadlift; infraspinatus, subscapularis, serratus anterior, trapezius for bench press). Data would be normalized to MVC and analyzed via repeated-measures ANOVA. Based on existing literature, I expect the squat to produce very high lumbar erector spinae activation (often 70-100% MVC), reflecting the need for spinal stability. Bench press is expected to show strong rotator-cuff activation. The deadlift likely yields high erector spinae and quadriceps EMG. Findings will be interpreted in light of mechanoreceptor feedback: e.g. greater foot and spine loading in squats may heighten proprioceptive drive to trunk stabilizers, whereas bench pressing predominantly activates shoulder mechanoreceptors that drive rotator cuff muscles. These results would clarify how proprioceptive mechanisms contribute to stabilization during different lifts, with implications for exercise selection and injury prevention.