An inevitable consequence of a prolonged career in a really physical sport is problems with your knees.

The sight of runners, riders and players wearing knee supports and bandages to offer that little bit of extra support is not uncommon - particularly at amateur level of the game as players look to exhaust every last possible option before they have to leave the field for good.

Most people are aware that because of the constant twisting and turning, or pounding the streets with an after work run, that they might get a bit of early arthritis in the knee joints, or wear and tear as many doctors and physios refer to it.

But one other consequence of keeping fit, that has hit the careers of many professional footballers in recent years from former Newcastle United player Craig Bellamy, to former England International Owen Hargreaves, is an injury called Patellar Tendonitis.

It's incredibly common in runners. It's on my list of the top five injuries that result from over training. So if you're a keen amateur footballer, or constantly looking to top up your fitness, you should be aware of this injury.

It's even more common on hard ground or indoor surfaces that five-a-side is often played on.

The Patellar tendon is the soft bit of tissue right at the front of your knee below the knee cap. It pretty much takes the stress of your leg as your foot hits the ground when you run. If the thigh muscle isn't strong enough, or lets say you've pulled the quad muscle recently, or had knee surgery, then this tendon is very likely to be weak.

When this happens, it can easily be damaged. And as the tendon gets damaged and begins to repair itself, it can sometimes be made worse if you do the wrong thing like continue to train with leg weights in the gym or don't allow enough rest in between sessions.

Bellamy and Hargreaves were two extreme cases. The former's career at Newcastle was blighted for some time by the weak knee tendon, and the latter's career almost if not completely ruined by this problem.

Both required surgery in an attempt to make the tendon a bit more elastic and tolerable to the stresses of the professional game.

It's the type of pain that will often stop when you do. So it's easy to keep avoiding the fact that you have to stop and do something about it. If not, the problem can last for months and even years.

In the teenage years it's a problem that is really common. If you're a parent and your child is complaining of a pain at the front of their knee that just won't go, there's a good chance that it's patellar tendonitis caused by the fact that the muscle is growing so fast and being stretched, it's now too weak to cope with the extra stress of physical activity such as football or running.

In runners, it's a classic case of over use as training gets tougher or miles get extended. Muscles that have been pushed to their limits are weakening under the strain and the cracks appear in this tendon. It can even be caused by poor fitting footwear something that should be looked at approximately every six months if you're a very keen runner racking up distances of 20 miles plus each week.

You can help yourself with stretching, ice and controlled eccentric exercise of the thigh muscles and ensure that your core control muscles around your back and stomach area are as good as they can possibly be.

n If you want to know more about this injury and other common running injuries you're welcome to come along to one of my 'Feel Great for Sport' talk-ins that I'll be doing this Wednesday at the Up and Running Fitness shop in Darlington, starting at 7pm.

I'll be talking about the top ten running injuries that I see as a physio and will explain how you can prevent them or reduce the likelihood of them affecting your training.

Places are limited, but if you'd like to come along please email Mic via darlington@upandrunning.co.uk to secure your place. If you'd like to arrange for a physio or Feel Great for Sport talk-in to come to your club, school or college, please feel free to contact me directly.