154) A 68 year old man presents to the clinic for progressive right hip pain. He reports pain in the right hip when walking more than 1 block and also, has difficulty putting shoes on his right foot. On examination, the range of motion is significantly limited in the right hip. An X-ray of the right hip reveals significant loss of cartilage, subchondral sclerosis and sub-chondral cysts. The patient is diagnosed with Right Hip Osteoarthritis and is started on Acetaminophen. Which of the following exercises should not be recommended to this patient at this time:
A) Stair climbing
B) Quadriceps strtengthening
C) Tai-Chi
D) Swimming
E) Bicycling
Archer USMLE Step 3 Blog 
Ans. A
http://www.americanarthritis.org/portal/loader.php?seite=practical_tips_for_knee_oa
A
FOR OSTEOARTHRITIS SWIMMING IS THE RECOMENDED EXERCISE
I feel the answer is A.
I will recommend that this patient avoids any activity that increases single leg stance on her right hip. (like stair climbing, tai chi with ‘flying kicks’) In this question, in every form of exercise listed, single leg stance can be avoided except in stair climbing.)
I feel the principle for exercise in hip joint injury in general is this;
1.Lets reduce the load on the upper body, both static (single leg stance and prolong standing) and dynamic(jumping or leaping or running).
2. Lets increase the lower body size, not with more fat, fat is uncontrollable; but with muscles.
How will muscles help?
Redistribution of pressure -With good quadriceps, and hamstrings, this patient can divert the pressure away from the area of pain (hip) to other lower limb joints like the knees joints.
Increased lower body structure stability and reduction in risk of falls – More muscles more coordination and movement control. Work is transmitted efficiently to functional joints and stronger muscle tone prevents falls.
Single leg stance increases the pressure on the all the joints in the active limb and this is bad for any injured joint on the active limb.
Telemeterized in vivo study on hip joint force data in Case Western Reserve University (highest joint pressure found in single leg stance)
http://www.ncbi.nlm.nih.gov/pubmed/1870027