I have had increasing muscle weakness in my thighs over the past several years at a rate disproportionate to my aging. I am very active and used to run marathons. It is most notable when descending a hill. Thighs will barely support me sometimes. Yesterday when descending a long steep climb my sense of balance seemed to fail. I leaning backwards and sideways, arms compensating at odd angles. I barely made it donwn the mountain. My girlfriend said I looked as though I had cerebral palsy. This has happened to me once or twice before, also while descending a long steep slope. My balance in general seems poor, and sometimes I feel vaguely vertiginous. My chiropractor took images of my neck a couple years ago and told me it looked like I d had a neck injury in my early years with now compromised spacing in the cervical spine. And I have been having increasing neck problems. My question is whether my muscle and balance problems might be connected to problems in the cervical spine or other spinal problems. Also someone mentioned Rhabdomyolysis to me. My urine is kind of caramel colored. Thoughts?