If you are a student, or do a desk job, you need to stand up and move your body. Especially your back muscles are lengthened and chest muscles are shortened (doesn’t mean your chest muscles are strong). To restore it to the original, the back muscles need to work. As working at the personal training gym for so long, If you are older people, it is almost too late to fix the posture.
Strength Training for Forward Rounded Shoulders
Strengthening the posterior deltoids and rhomboids is associated with forward rounded shoulders. Dynamic strengthening exercises for good posture, do not involve heavy loads, but rather volume training to condition the type 1 fibers.
The strengthening of weakened muscles follows a progression model beginning with two to four repetitions of isometric muscle contractions.
Each time held for 5 to 10 seconds and do 2 to 4 repetitions. Starting with holding the scapulae in a good postural position and avoiding scapular protraction and retraction during the movement.
How to Progress from here
One to three sets of 12 to 15 repetitions. with dynamic, controlled full range of motion including scapular retraction.
Stretch / mobility exercises for rounded shoulder here