HIP POSITION. You are correct. The 135-degree angle is biomechanically ideal for hip osteoarthritis. Hip abduction (spread of the legs, i.e., knees apart) is also important.

BODY POSITION. The best way to achieve the ideal hip position varies with the body’s position in space. For upright tasks, a saddle chair makes sense. For reclining tasks, a zero-g recliner makes sense. What doesn’t make sense, is to use a saddle chair for TV watching or a reclining chair for computer tasks.

GRAVITY IS YOUR FRIEND. Don’t forget, your bones and muscles need gravity to stay strong. Your core muscles are dormant in a reclining chair, but active in a saddle chair. Sure, watch your movies and read your books in your recliner, but make sure you spend sufficient time during your waking hours, actively moving when you are upright. An hour at the gym cannot combat 20 hours of recumbency. You will lose that battle in the end.