h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

For reasons of left knee is quite weak (probably injured plaing in goal on rock hard ground as a youth).
Is there any way of excercising it in isolation without the need for equipment?

My grandfather had problems with his knee and used to sit in his chair with half a brick suspended below his foot in a cloth, and lifted it ten times a day and then increased the number of lifts over time. His doctor recommended the excercise. How about that one?

Sounds feasible...though I might use an ankle weight instead, for appearances sake .

Use an ankle weight. Sit in a chair with your thigh completely supported the whole way along. Hold the chair with your hands, so that there is not strain on your back. Better still, lie on your back on a table with the edge of the table just at the crook of your knee.

If you want to tone the muscles, use a small weight and do a large number of repetitions (say, 1 kg). If you want to build the muscles up, do a smaller number of repetitions with a bigger weight, say 5 kg or even 10 kg.

I work on a chalet site for my parents. The chalet site has 108 steps I have to walk up and down every day to get to the bus stop which is over a long 1/4 hill. I work during the summer lugging the tourists luggage up the steps. I would suggest staying at the chalet site as a kill or cure solution. It keeps me reasonably fit even if I avoid going up or down it

The walking thing is good, and I do try and go for a walk when I can..but it's just the left knee that is weak, so it tires way before the rest of me.
I will try the raising the leg exercise this evening...

The best knee-strengthening exercise is probably swimming. This will exercise every muscle in your body without any serious risk of straining. A friend of mine who had a knee cartilege replacement was forced by her doctors to take up swimming even though she disliked it intensely at the time. It worked wonders.

When I cracked my pelvis last spring, the Fiend in Physio had me strap ankle weights on, lay on my back on the floor with my knees bent, and raise my leg till the knee was straight, then slowly lower it back down. Muscle tone went away from my ankle to my hip. It worked, the strength eventually came back into my knee.

When I dislocated my kneecap about 3 years ago, I was given the follwing excercises by the physio:

Excercise 1 - Sit on the floor with your back against the wall. Roll up a towel tightly and place it under the affected knee. Pull your toes upwards (don't use your hands) and twist your foot outwards. Then straighten your leg s-l-o-w-l-y, hold for 5 secs and lower it s-l-o-w-l-y. Repeat 10 times.

Excercise 2 - Stand on the affected leg and turn your foot outwards. Slowly lower yourself until your knee is bent to 90 degrees, hold for 5 secs and then raise yourself slowly.

Cycling is also very good.

BTW, when twisting your foot outwards, make sure that your knee still faces forwards.

Basically, it's the muscles in front of the thigh that hold your knee together. My dislocation was caused by the muscle on the outside of my thigh being stronger than the one on the inside.