for a workout I would try a full body 3 times a week. Slouching is from posture not weak muscles.

i am 6'6" and weigh about 200lbs and am 28 years old. 185-190 is more my ideal weight as my body frame just doesn't seem to comfortably hold anything more very well. the majority of weight after 185-190lbs goes straight to my belly, and even though i'm over ideal right now, i don't have a big gut at all. i have attempted in the past to work out and eat a lot of food, but i always seem to max out at around 200lbs.
since i'm lanky i've always slouched and had lazy shoulders. it's hard to hold them back and even harder with the little extra weight in my stomach as of late (think anthony bourdain from 'no reservations' on the travel channel). i will consciously think about pulling my shoulders back, but after a while it actually is quite difficult.
i typically play a lot of golf and walk 9-18 holes per week and that is my exercise, and i plan to soon buy some dumbbells and do dead lifts and squats to increase some core muscles to help me in golf also. i have a stress fracture and my foot and haven't played in a few weeks, so i haven't gotten any cardio exercise and now that weight gain is catching up to me.
a friend of mine has a personal trainer who i chatted with socially one night, and he said the slouching is due to weak muscles on the back of my shoulders. he pointed and i think he called it the rear deltoid? i'm not really sure. anyway, he suggested rowing exercises would increase that muscle, but i don't know any easy rowing exercises that i could do.
can anyone validate that these muscles could be my problem and possibly give me some suggestions for types of exercises that would help my constant slouching problem? thank you very much in advance.
for a workout I would try a full body 3 times a week. Slouching is from posture not weak muscles.
X2 for posture
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