Comment Strength training and exercise (Score 1) 235
The best you can do with a good ergonomic set-up is to minimize the negative effects of spending hours in front of a computer.
So sure: get a decent chair, make sure your monitor is set to the proper height. Experiment with sitting/standing configurations. Use a laptop or tablet (or book) periodically which lets you get away from your desk. Get up and walk around every hour or so. That will all help.
But what fixes your musculature and skeletal is actually stressing it. Yeah, weight training. 2x weekly minimum, 3x is a good standard, 4x if you decide to go gung-ho. 30-90 minutes per session. Focus on your backside ("posterior chain"): calves, hamstrings, glutes, spinal erectors, lats, traps. Movements like squats, deadlifts, rows/chins, and kettlebell swings. You're going to want to do a full-body program ultimately for balance, but the lifts above are going to be key.
Simply supporting your body in a comfortable state will disengage musculature, as will rests, splints, and other crutches. What builds and strengthens muscle is progressive overload.
For more on this, a great starting reference is The New Rules of Lifting by Schuler & Cosgrove. Mark Rippetoe's Starting Strength or Stronglifts 5x5 are good beginning strength programs.
Toss in 3-4 sessions of cardio, including some HIIT interval work 1-2x weekly, and you'll be in far better shape. Particularly as you get older. Which I hear happens in time.