The muscles in around the upper leg are the largest in the body - both those on the front of the thigh, and those to the rear - the hamstring and the gluteus maximus. They generate huge amounts of force, and so it figures that when things go wrong, they can go seriously wrong.

If you watch a typical person work out it's pretty easy to see why these injuries occur. In an average workout of an hour, someone might do twenty minutes of CV, thirty minutes of upper body resistance work, five minutes of abs, and maybe five minutes working on their upper legs and their flexibility.

If that sounds familiar, and your workouts are similarly out of balance, then it's time to start paying more attention to your upper legs. This is a crucial area, for a number of reasons. First and foremost, almost any sport or activity relies heavily on this area - whether it's walking or running, dancing or doing an exercise class, you are on your feet and moving. Secondly, you need to aim for balance in both your workouts and your appearance. A lot of guys at the gym have massively developed chests and arms, but appear to be walking around on matchsticks.

Finally, strength and flexibility here is vital for good health. Many low back injuries could be prevented by better flexibility through not just the low back, but also the hamstrings. So if you want to avoid injury, sharpen up your appearance, and improve your sports performance, take a cue from top body builders, who spend hours doing squats and other associated exercises. It's all about balance.