20
Feature
Dr Jodie Richardson
The
N I A R T S is showing!
n HAMSTRUNG: Nick Riewoldt tears his early in the 2010 season.
Hamstring injuries remain the curse of the AFL footballer, and just as elusive for researchers trying to pinpoint their cause.
H
AMSTRING strains topped the recently published 2010 AFL Injury Report, again coming out as the most common injury among footballers and that responsible for the most missed playing time. It was no great surprise given that hamstring strains have been the most frequent and costly injury in the AFL for more than 10 years. No player is immune to the devastation that these injuries can bring and recent years have seen some of our biggest names hit the turf with the pain, shock and disappointment of a serious hamstring strain. Nathan Buckley, James Hird, Nick Riewoldt, Daniel Kerr and Matthew Lloyd – to name a few – limped off the field with the tell-tale hand on the back of the thigh, their supporters equally devastated. You’ll hear on the news and read in the papers that a player has “done” a hamstring or their hammy has “gone”. In both cases the player has strained a hamstring muscle. This can range from a “first degree” strain where some of the muscle fibres are torn to a “third degree” strain where the tear extends across the whole muscle. A first degree tear will usually see a player out for three to four weeks, where a high-grade tear could see a player under the knife and in rehab for months.
Not only are hamstring strains costly for the player and the club in terms of performance, they are costing the clubs a packet. The Collective Bargaining Agreement for AFL players stipulates that they are entitled to 100 per cent of their usual match payments for up to 30 games missed as a result of an injury incurred while training or playing. Given the average number of games missed through hamstring strains for each club in a year is 20, this adds up to a notional cost of hundreds of thousands of dollars annually in payments to injured players and their onfield replacements. This injury presents an age-old problem for the AFL, and mountains (or more aptly forests) of research have been conducted into this perplexing injury over many decades. Given the research into the causes and prevention, it’s surprising to see that the average number of new hamstring strains each year in AFL clubs now (six) is exactly the same as it was in 2001. The obvious question is why hamstring strains are still so common when so much research time and money has been poured into solving the problem? Even the likes of Nathan Buckley, with all of the resources of the Collingwood Football Club at his disposal and the most experienced medicos in the coun-
try working with him, was not immune to this unforgiving injury. Hamstring injuries are the most common injury in sports involving rapid acceleration and sprinting. There is no question that the speed of our game has increased phenomenally over the years, which makes for an awesome spectator sport, but this has come at a cost. A study entitled Evolution of Australian Football showed that the speed of the game doubled in the period 1961 to 1997. Of course with the introduction of a fourth interchange player, the game had never been faster. Unfortunately, an overall increase in injury rates paralleled this increase in game speed. Research has shown that the incidence of hamstring injuries decreases as running speed is decreased. However, it remains to be seen whether the latest changes to the interchange rules, replacing one interchange player with a substitute, has the desired effect of reducing game speed, hamstring injury rates and injury rates in general. The hamstrings are comprised of three muscles on the back of the thigh that cross both the hip and the knee joints. Inside Football
Picture a classic football photo of a player just after kicking the ball, support leg vertical, kicking leg horizontal to the ground with the hamstrings at full stretch, the hip joint flexed and knee joint fully extended. During activity, the hamstrings repeatedly develop force while at the same time being lengthened, which can lead to overstraining of the muscle fibres and subsequent injury. Along with these functional aspects of the muscle group, there are several risk factors that make a player more susceptible to a hamstring strain. Researchers have conclusively shown that AFL players over 24 years of age are four times more likely to suffer hamstring strains than players 18-23. Also, players who have sustained a
Wednesday, May 18, 2011
hamstring injury in the previous 12 months are at increased risk of another hamstring injury to the same leg. The problem with age and injury history is that they are irreversible risk factors. Other known risk factors that cannot be modified include indigenous race, though these players may be more likely to experience hamstring injuries purely due to their talent for speed. Previous injury to the calf, knee, ankle or groin can also render a player more susceptible to a hamstring injury. Research around other potential risk factors including hamstring strength, hamstring to quadriceps strength ratio, flexibility, fatigue, influence of warmup, neural tension, optimum knee angle