TONIC VS. PHASIC MUSCLES
Poor posture arises for two main reasons:
Tight Tonic Muscles — Your tonic muscles are responsible for holding your posture. They can constrict and tighten making it more difficult to achieve and maintain correct posture. You need to stretch these muscles to increase your range of motion so that you can improve your posture.
Weak Phasic Muscles — Your phasic muscles are used for dynamic movement. They can weaken and lengthen, making you more prone to slouching. You need to strengthen them so that your neck and back can maintain proper posture all day.
To offset our modern lifestyle, we need to actively care for our postural muscles. The Posture Medic was created for this purpose. We cannot simply rely on being conscious of our poor posture. Periodically remembering to sit or stand up straight will not create lasting effects. We need to stretch, strengthen, and stabilize the region in order to correct poor posture.