The guard and Bodyshots

[dtravis92]

Maybe he meant to keep your back straighter, not necessarily stand tall? You could have been leaning over and ruining your posture, using your back to get lower instead of just bending at the knees to lower yourself down while keeping your regular stance.

[cambay411]

Its ok to stand tell if your a tall fighter, but you always want to have a slight bend in your knees and stay on the balls of your feet of course