Window cleaning isn't fitness its rsi
Started gym again last month, feel a lot better already 6lb lost.
I'm 15 years WFP and I feel better now than I did in the first few years of WFP.....
The problems with strain were varied and a combination of
Body not used to using poles after 17 years on ladders
Inferior equipment which included aluminium/fibreglass poles,heavy brushes and trolley systems
Working too many hours
Taking on too many add on jobs in one day/week.
After 9 years of regular strength training in the gym(I started back in 2016 aged 44)I've managed to build a significant amount of muscle all over but particularly in my mid/upper back/shoulders and it helps a lot in reducing strain esp at awkward angles.
My overall diet is much better and so is my sleep routine which should never be neglected.
Window cleaning is a healthy job working outdoors as long as your not working long hours IMO