At any one time something like 30% of runners are injured. That is quite an amazing statistic and was presented to me by world leading running coach (and POSE method inventor) Nicholas Romanov.

What causes this problem is a number of issues and too large (probably a whole books worth) an issue to discuss here.

Hands up if you run and have suffered from knee pain at some time or another!!

Don't worry you are not on your own as I alluded to above, many people who are runners struggle with injury's that stop them running or competing at some point.

What that means is that you are not able to do what you love or need to do (especially if you're training for an event)!!

Most people tell themselves they're just being 'whimps' and run through it. Fortunately (for them) some people stay injury free for quite a while. This all changes when years of compensation and altered mechanics leads to a breakdown...at some point!!

Hip extension is essential for good running mechanics.

If you are not sure what hip extension is then stand up, with your feet together. Lift one foot off the floor and with a straight (or bent) knee push that foot back so that your thigh moves backwards...that's hip extension.

If you don't have enough hip extension then you'll have to compensate for it some where else in the body (usually the low back, but that's for another day).

If you are lacking hip extension then you end up overworking your muscles around the knee.

When you start to overuse any muscles you put the body in a position where it changes the balance. Joints need balance between the muscles in order to make sure that they stay in the right alignment and no undue 'stresses' are placed into the joint.

I work in a busy sports injuries clinic (www.kineticfitness.co.uk) and I would have to say that the physiotherapists I work with tell me that in 90% of cases knee pain, that people report, has nothing to do with any degenerative problems around the ligaments, tendons or cartilage.

Most of these 'presenting' knee pain patients are actually people who have massively got their muscle balance out of kilter.

So what can you do about it?

As well as a complete corrective exercise plan, one of the first things we work on is hip range of motion.

I know, you hate stretching!!

That's because human beings tend to gravitate towards the things they like doing most and avoid the things they like doing least.

If you don't stretch it's probably because you find stretching hard and painful. Well unfortunately you are the type of people who need to do more of it.

So the key is to put the muscles like the quadriceps and hip flexors in a position that will maximally get them to stretch and relax.

This is my absolute favourite hip flexor stretch and an essential for all runners to do.

I've put it on you tube so that you can see it:

http://www.youtube.com/watch?v=H5uz3DE-FEc

Just in case you can't get on there, here's a brief description:

1. Place your foot on a bench or a Swiss ball so that your laces are in contact with the surface, and the knee of that leg is on the floor (your leg will have a V angle). 2. The other leg should be in front of you with the foot on the floor so that you are in a lunge like position. 3. Keep the back straight and the buttock on the same side (leg that is being stretched) clenched. 4. You should feel a stretch stating at the knee and moving all the way up to the front of the hip or anywhere in between, it depends where you lack the flexibility. 5. Make sure that you are 'tipping' the pelvis (tuck your bum under your body) so that you are stretching the thigh and not compensating for the movement in your low back. You will know you are doing this if you have a big low back curve. 6. The low back should be relatively flat or slightly rounded. 7. Hold for 30 to 60 seconds.

I highly recommend watching the video for a full explanation.

One of my clients called Rachel was suffering with some really bad knee pain. She was referred to me by a sports physician because she was suffering from patellar tendonitis.

The primary exercise I set her to complete was exactly this. She now does this on a daily basis; in fact she should be doing it at least twice a day. That's because she works all day sat at a desk.

This means that not only have her muscles adapted to the lack of flexibility at her hip, but she gets the double whammy of making them tight and short all day long at work.

You don't need to do this stretch for hours on end simply complete it a couple of times a day to really get the muscles up the front of the leg relaxed and lengthened. You should start to feel some of the pressure and tension in the knee releasing the more you do it.

This obviously is not a panacea for knee pain but is definitely one of the easiest and simplest places to start.