On PBP 2015 at about 600 km I started to suffer from my knees moving laterally so that my right knee started to hit the crossbar bag. It was as if I was sagging to one side but I couldn't push the bike upright. The legs were fine and I felt no weakness in them. At about 750 km I lost nearly all of my upper body strength but I managed to complete the ride. I made what I think was a false assumption that they were related and it was a core issue. I did core exercises in the run up to PBP 2019 but to no avail as when I hit 400 km the problem arose again (I had done the Porkers and Brimstone and experienced nothing). I was really depressed as I could not envisage cycling 800 km with my knee hitting the crossbar. After sitting by the side of the road considering packing, I decided to cycle on to Carhaix where I went to see an event physio called Jerome. He was great and spent some time massaging my shoulders which were very knotty. I cycled on and it was ok but after 25 kms it returned and I had to stop every 7 kms to stretch the shoulders and neck. I slept for 3 hrs at Brest and next morning it seemed to be alright although I thought it may have been coming back a couple of times. When I reached Loudeac, Jerome massaged my shoulders again and I didn't really notice the problem after that. Interestingly the upper body weakness of 2015 never manifested itself so I assume that was a separate matter resolved by the core work. I am wondering if anybody else has experienced this problem and has a solution, I have spent some time Googling it but found nothing. Thanks Sean