My county is sponsoring Nordic Walking for general health and Age concern seems to be involved as well.. Once you've done the technique training and got your card to prove it, you can walk with voluntary leaders or any other organisers for that matter. So I'm wondering if any other Counties are doing the same. Nordic walking (i.e.with two poles) makes you walk (and therefore inclined to stand) more upright and also therefore improves your breathing, takes a good deal of the strain off your hips and knees, provides aerobic workout much more so than when walking without the two poles. I've seen it recommended for PD, MS and other movement disorders.
My hip problems started three or four years before other PD symptoms. Fortunately I did not believe the Dr's knee-jerk age related (I was 65 at the time) diagnosis of arthritis. Otherwise I might be the proud possessor of a new hip by now which I strongly suspect has been the case with other PWP's I''ve read about.
I am sure the yoga classes I followed for many years stand me in good stead with the PD - stretching and weight bearing for the muscles being just one aspect
I have not managed to find a class for myself yet but many PWP's find Tai Chi is very good for balance and core strength lack of the latter being one reason for slouching.. Related to this was that I noticed some years before dx that I kept sliding down when sitting in an armchair or in bed just like my mother-in-law did who I knew had had PD. Did not feel I could go to the doctor complaining of this and having to abandon my breakfast in bed habit (!!!) but I knew something odd was going on.