Hello all I have grade 4 artharitus in my right knee, due to an old football injury, i still train 4 days a week but only upper body!! Chest, back, shoulders, arms!

I've trained for over 10 years and am now 33 and not feeling to good about things!! And now due to pain, lack off movement and no cardio for as long as i can remember, I've put on some timber and want to shift it!!

Has anyone got any ideas or suggestions for me please? I'm Really stuck here!! I'm sure if paraolympians with legs missing ect can do cardio, then there must be something I can do!!

I am in constant pain and if anyone has been in this position please let me know how you got on or what you do to improve things

Thanks for any advice