You may have noticed that looking after a baby (or any small child) requires your body to perform some pretty frequent movements:
Lifting them up;
Carrying them in front of you;
Bending over them in their cot;
Leaning forwards to feed (I never nailed 'comfortable').
All these movement patterns work the muscles at the front of your upper body (chest, upper chest, shoulders and biceps) causing them to become strong, short and tight. In comparison, the muscles of your upper back respond by becoming overly weakened and stretched.
This has the effect of drawing your shoulders forward so that they are rounded (often described as a 'hunched') position.
In order to rectify this, your postnatal workouts should be designed with a focus on the opposite.
Strengthening the back
Stretching and opening up the chest.
Over time (consistency is key), this has the effect of pulling the shoulders back to open up your chest so that you can walk taller, look more confident and feel better.
Whilst you can still work the muscles of the front of your body to some extent, spending too much time on pressing exercises will only serve to build more muscle in these areas and exacerbate the tightness. These shouldn't be the dominant movements in your upper body workouts (unless that's the look you're going for).
Ideally you should follow a plan that emphasises training the muscles of the back of your body by including pulling exercises such as rows, pull-downs, pull-ups, deadlifts and reverse flies.
Want to learn how to train your body for efficient, effective results?
I place particular emphasis on training the muscles involved in improving your posture (as well as getting you super STRONG. Obvs).