If you need to get fitter but are being held back because of problems with your knees then take a look are the simple knee strengthening exercises below.

This first exercise is really good for those who suffer from conditions such as chondromalacia patella. This is an inflammation of the cartlidge beneath the patella 'knee cap'. This sometimes results because the bones and muscles on the knee are out of alignment.

A really simple exercise that will help is as follows:- Sit comfortably on a chair, try not to tense up, you need to relax, have your thigh parallel with the ground, leg bent and 90 degrees, feet on the ground, tense the thigh, then hold this position for five seconds and release the hold, do the same with the other leg. Complete ten reps on each leg.

It is very important to remember to breath whilst doing these exercises.

If you want to build up a little more strength in your knee you may want to try the following exercise.

Sit in a chair again, then cross your bent legs at the ankle. Push your legs forward with the rear leg then push them back using the front leg. (At first this can seem a little tricky but it is really easy once you get used to it!).

Rearrange the position of your legs by changing the direction you have then crossed at the ankle. If the right leg was in front, move it to the back. Repeat this exercise 10 times for each cross-over position.

Calf Burns

Now for something a little more strenuous.

If your balance is not all that great it may be a good idea to do the following exercise whilst standing on a may, carpet or at least a wooden floor. Try to avoid doing the exercises on a metal or concrete floor.

Stand upright, heels together, toes a little apart. Make sure to keep your balance.

Lift the heels, balancing on the balls of your feet. Try to imagine an invisible string attached to the center of your head pulling you up. Hold for five seconds, then lower slowly. Repeat ten times. Eventually, as you build strength and balance, you can increase the length of time you're on the balls of your feet.

To intensify this exercises a little try bending your knees whilst you have your heels raised. By doing this you will also be using the muscles in your quadriceps, hamstrings and buttocks. Remember to straighten your knees then lower your heels. Do ten reps.

If you can make sure you carry out these knee strengthening exercises a couple of days a week or better still daily, you will have strong, healthy knees in to time at all.