I am an 84 yr old. I am 5 ft 7.5 in. And weigh about 180 lbs. I have extreme weakness in my legs. In the past I could move fast and not tire out. Now, I walk just one row in the grocery store and I am whipped and my legs are very weak. I am starting physical therapy next week but want to know if there is anything else I can do to improve my leg strength? Ice fishing season is finally here and I want to go, but walking on the frozen lake my be too hard for me. HELP.