Sporty secrets of a healthier hamstring

Every armchair football fan can spot a hamstring injury. One moment a player is in full flight in pursuit of the ball, the next he's rolling on the ground clutching the back of his thigh.

Unfortunately for Liverpool and England fans, it's a sight that's been all too common during the professional career of striker Michael Owen, who at 22 is one of the greatest young talents in the game. His remarkable success has been marred only by prolonged spells on the sidelines because of hamstring injuries.

As Liverpool prepare to face Roma tonight in a match they must win to stay in the Champions League, and England boss Sven-Goran Eriksson continues work on his game plan for the World Cup finals in June, the question of Owen's hamstrings begins to take on added significance.

But what is it about this long, thin group of muscles in the back of the thigh that so threatens all sporting ambition, from the professional footballer at the peak of his career to the average keep-fit enthusiast?

In short, says Dr Stephen Motto, sports medicine expert at London Bridge Hospital, it's because the hamstring muscles are big and hardworking. They are one of the larger groups of muscles and their job is to extend the hip and bend the knee, both very important actions if you're sprinting or running.

"Because they extend to both joints above and below, they have a much more complicated action and can be injured more than any other muscles. You're supposed to stretch the hamstring muscles to avoid injury, but some footballers don't, and if you tear it once, you're more likely to do it again."

Hamstrings are actually made up of three different muscles, all closely intertwined - the biceps femoris, just above the back of the knee, the semimembranosus muscle in the middle of the thigh and the semitendonosus muscle above that.

In normal daily activity there is no threat of injury. But like any muscle, if you ask the hamstring to do something it's not used to - or you haven't prepared it for - it could struggle to cope.

What normally happens is that the muscle is forcibly stretched beyond its limits and the tissue becomes torn. Physiotherapists break tears down into three groups.

A first-degree strain is damage to just a few muscle fibres. You may only notice once you've stopped exercising that there is a sensation of cramp or tightness and a touch of pain when the muscles are stretched or contracted.

A second-degree strain means more severe damage to a larger number of fibres, with immediate pain and tenderness in the damaged area.

As for grade three, this is what the experts call a "catastrophic" injury - a complete rupture of the muscle itself. There is an immediate burning or stabbing pain and agony when you try to walk because the muscle is completely torn. After a few days, a large bruise will appear, caused by the bleeding within the tissues.

The mystery behind why some sports stars appear more susceptible to hamstring tears than others may partly lie in their genes. But many can be blamed on straining the muscles when they are fatigued or not prepared properly. Warming up first increases the tissue temperature and makes it more extendible.

In football, which demands a combination of speed, agility and endurance, the pressures put on the hamstring can be considerable, as is the potential for muscle damage.

As Owen fans well know, recovery from hamstring tears is painfully slow. Even with mild hamstring pulls, doctors usually order rest from sport for three to four weeks. In the worst cases, it can be several months.

"You've got to tone the muscle up again to be as strong as the one on the other leg, otherwise you overload that one," says Dr Motto. "You've got to listen to what your body's telling you."

Make the most of those muscles