Thanks James, that is a lot of support reading your post. I do have access to a great South Indian Vedic Doctor who has taught me a some good Asanas and Yogic exercises.
I do listen to my body, and I also get my bokken with me, and whenever I feel slight pain starting in my knee, or any other place, I spend the rest of the class practicing bokken strikes.
Thanks for your post. I appreciate it.
Welcome and perservere with the training. I am 6ft 5 and of big build and have been training for 14 years and initially had various aches and pains. I would agree with your sensei just do as much as you are comfortable with and take it slow and easy. You are in it for the long term.
I would recommend hatha yoga which is gentle and will help increase your flexibility (it was of great help to me and I went for a year). If you do not have access to a good yoga centre just try gentle stretching every day. Resting your joints and muscles is equally important as it allows your body to adapt.