A total of 36 older (age=65-79 yrs), obese (BMI=30-40 kg/m2), sedentary men and women with x-ray evidence of knee OA will undergo a 22 week weight loss intervention (targeting 10% weight loss) with randomization to one of two groups (n=18/grp): 1) No vest use (Control); or 2) Progressive weighted vest use during normal daily activities (VEST).