Alex Libin 李彬 on Instagram: "Brothers and sisters with sagging faces, double chins, and poor posture – stop wasting time on the wrong exercises! In today’s video, I’ll show you 4 simple yet powerful back exercises that will help you transform your posture, slim your backs, and even define your jawlines in just 4 weeks! You don’t need any equipment – just grab a towel and follow along at home. 👉 Say goodbye to hunchback, double chin, and saggy posture – and say hello to your beautiful back, conf