Future articles will include information on diagnosing how severe the injury is, your prognosis for return to sport, what to do in the initial injury stage and reducing your risk of future injury. We will also discuss common beliefs on stretching and “core” muscles relative to hamstring injuries.

How common are hamstring injuries?

Hamstring injuries are most common in sports that involve running and sprinting. They account for 17-30% of all injuries in sports such as Soccer, GAA, Aussie Rules, Rugby, and Athletics.

How do you injure your hamstrings?

Simply put, the hamstrings fail to absorb the force through the muscle; the muscle unit fails and results in a muscle tear. Hamstring muscle injuries most commonly occur when the athlete is sprinting, just as the front heel is about to touch the ground. This is the position at which the hamstrings are most vulnerable; therefore it makes sense that this is the most common position for injury. It can also occur in other positions such as an overstretched position and also just as the athlete is about to take off in a sprint.

Why is there so much talk about hamstring injuries?

The data for hamstring injuries show that on average per club (soccer, rugby etc), they will have 5/6 players with hamstring injuries per season. This results in approximately 21 missed player games per club per year. There is also a high re-injury rate of 12-31%, which leads to even longer absences.

Who is most at risk?

Those most at risk are male, over 23 years with a history of a previous hamstring injury.

Previous injury

A history of a previous hamstring injury means you are 2-6 times more likely to re-injure your hamstring. You are most at risk in the 3 weeks you return to sport. For the year post injury you are 3 times more likely to sustain a hamstring injury.

Increasing age

Any athlete 23 years or older has up to a 4 times greater risk of hamstring injury. This risk of hamstring injury increases by 30% annually.

Muscle weakness and Strength imbalances

Weakness and imbalance in the quads and hamstring muscles has been shown to be associated with future injury. In previously injured hamstrings, weakness has been shown to continue to exist long after the player has returned to sport.

This is very important because this is your main modifiable risk factor. You can’t change the fact that you have injured your hamstring previously or that you are getting older but you can address weakness and muscle imbalances. This will be the focus of some of our future articles i.e. what exercises to do when you are injured and also what exercises to do to decrease your risk of future injury.

Feel free to share this article and if you would like us to discuss other areas in more detail just let us know. If you have a current hamstring injury or think you are at an increased risk of hamstring injury please feel to contact us for advice or an appointment on 0851670574 or charteredphysio@gmail.com.

Thanks,
Michelle & Órla
ProActive Physio

1. What are the most common hurling injuries?
2. Are Hurlers less fit than Gaelic footballers?

This study followed 4 inter-county teams, a total of 127 hurlers, for a full season.

82% of players were injured during the season. That is 204 injuries to 104 players.

In a squad of 30-32 players, one can expect 4 players to be injured in any given week.

90% of these injuries were mild-moderate i.e. they took 1-4 weeks to recover.

The period when the greatest percentages of players were injured was mid-season-April.

Over 60% of match play injuries occurred in the second half more so in dry conditions.

70% of injuries were to the lower limb.

Muscle strain was the most common injury. Hamstring injury topped the poll at 16.5 % followed by quadriceps strain or haematoma, then ankle, groin, and calf.

There was a 7.4% incidence of fracture, mainly to fingers and thumbs.

How does injured tissue in Hurling compare to other sports?

Comparing hurling to other field sports

Incidence of injury per 1000 hours of training and per 1000 hours of match play

Comparing hurling to other sports that use sticks

With the exception of Rugby League, hurlers are more susceptible to injury compared to other field sports. The incidence of injury is much higher than other sports that use sticks and researchers argue this could be related to larger playing field of hurling compared to ice hockey or lacrosse. The incidence of injury in training is similar to Gaelic football and soccer but the match play injury rate is much higher in hurling.

There is an argument that hurlers are less fit and have poorer strength and conditioning profiles. A study looking at the physiological profiles of elite hurlers reported a higher percentage body fat, lower speed endurance, lower estimated VO2max and lower abdominal endurance compared to elite soccer players. In comparison with Gaelic footballers, Hurlers showed lower speed endurance and reduced upper body strength.

However, hurling is more a skill-based than strength-based sport. By the age of 14 or 15 years, most hurlers have achieved the golden 10,000 hour expert rule. It is a sport where a small ball weighing 120 grams travels through the air at speeds of up to 160 km/hr and must be balanced on a stick while running at speed, caught and struck in the air while being tackled. Acknowledging it is a skill-based sport, it still has a disproportionate share of match injury, predominantly muscle strain not impact injuries. Perhaps if we improve the strength and conditioning profiles of our hurlers we may see a decrease in their injuries, prolonging their careers and maintaining their skill on the pitch in our unique national sport.

1. Murphy et al 2012 “Injury in elite county-level hurling: a prospective study” Br J Sports Med 2012;46:2 138-142 Published Online First: 19 October 2010 doi:10.1136/bjsm.2010.072132

2. McIntyre 2005 “A comparison of the physiological profiles of elite Gaelic footballers, hurlers, and soccer players” Br J Sports Med 2005;39:7 437-439 doi:10.1136/bjsm.2004.013631

3. Murphy et al 2012 “Incidence of Injury in Gaelic Football: A 4-Year Prospective Study” Am J Sports Med September 2012 vol. 40 no. 9 2113-2120

Match Play Injury Risk

Gaelic Football had a match play injury risk that was greater than soccer but less than rugby.

Gaelic football match play injury risk is 1.5 – 2.6 times greater than soccer.

Match play injury incidence is 68% for Gaelic football and 74% for rugby union.

Training Injury Risk

Gaelic football training injury rates are higher than training injury rates for rugby union.

Gaelic football training injury incidence is 4.06 per 1000 hours compared to 2 – 3.5 per 1000 hours for rugby union.

Discrepancies in injury definition and division between training and match injury rates in the research does not allow for direct comparison between Gaelic football, AFL and rugby union.

Injury Rates per Season

Over the four year study there were 1.19 injuries reported per player per season. In a squad of 34 players that accounts for 40 injuries over the season.

86% of these injuries will result in loss of match play for at least one week.

Location of Injury 

Hamstring injury was most common, accounting for 24% of all injuries. Cruciate injuries accounted for 1.5% of all injuries.

Tissue Injured                                  % of all Injuries                      Days to return to play

1. Muscle                                                  42.6%                                19.7
2. Ligament                                                13.2%                                 25.3 (excl Cruciate)
3. Tendon                                                   9.2%                                   32.4
4. Bone                                                       4.4%                                   38.7 (excl severe fractures)

Murphy et al (2012) Incidence of Injury in Gaelic Football: A 4-year prospective study The American Journal of Sports Medicine Vol. XX, No. X DOI: 10.1177/036354651.2455315

1. Squat 

Strengthen your back, hips, gluts, quads and hamstrings 

2. Heel Raises 

Prevent calf and achilles injuries

3. Lunges 

Stretch and strengthen all-in-one

4. Yoga Favourite 

Hands-down King of the stretches

5. Single Leg Squat 

Gold star exercise for all runners!

With the GAA club season starting back this month, here are my top 5 tips to help stay injury free

1. 1 ) Rehab your old injuries

A past history of injury means you are 2-3 times more likely to get that same injury again. If you haven’t completed a comprehensive rehab program then you are at an even greater risk. There are preventative exercises for all the common GAA injuries; hamstring, ankle, shoulder etc. find out which exercises you need to do…and do them!

2. 2 ) Monitor your training schedule

There are two main training errors that increase your risk of injury

1. a ) A sudden increase in load (ie the amount you are training)

Your risk of injury increases when you increase your training load by greater than 10% per week. Gradually increase the amount you are training and your body will adapt, increase it too quickly and you are far more likely to get injured.

2. b ) Overtraining

If you are playing on more than one team you need to speak with team managers to ensure you are doing enough of but not too much speed, fitness training. If you are constantly training to fatigue your body does not have enough time to recover, leaving you open to injury.

3. 3 ) Get your diet right

Get enough carbohydrates and protein into your system to

A. Fuel your workout: Insufficient carbohydrates pre-session means you won’t have enough energy to complete the training session efficiently

B. Recover after your workout: Inadequate protein post session means your body doesn’t have the building blocks to repair and rebuild new muscle.

Deficits in either puts you more at risk of breakdown in your subsequent training session as your body has not adapted to the previous.

3. 4 ) Get enough sleep

Anything less than 6 hours of sleep per night lowers your immune system and decreases how well your body recovers from exercise. It also puts you more at risk of heart disease, stroke, diabetes and depression.

3. 5) Keep up the Strength & Conditioning

The gym is not just for the winter! Ideally you should be on a program that incorporates sports specific periodization so you are maintaining power and strength for the competitive season. You should also include your preventative prehab exercises to decrease your risk of recurrence of an old injury.

If you want advice on how to help prevent particular types of injuries, let me know!

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No other injury garners more media attention, with high profile players side-lined for at least 6-9 months. It is a huge blow for the athlete, eliminating them for the season, and is often associated with negative psychological responses of anxiety, fear and sometimes depression.

Cruciate injuries are more common in sports that involve high speed, sudden, rotational movements. Recently there have been claims of a “cruciate curse” and reports of an epidemic of this injury in the GAA. It might be more helpful to athletes and coaches if we can sort fact from fiction and have a look at; why this injury occurs, who is most is risk, who is most at risk of re-injury and if there is anything we can do to help prevent this injury occurring. We will also make a comparison across certain sports where the incidence of cruciate injury is higher than in the general population.

What exactly is the cruciate?

We actually have two cruciates, in both knees; the ACL (Anterior Cruciate Ligament) and the PCL (Posterior Cruciate Ligament). An ACL injury is the one we hear all about, as injury of the PCL is generally managed without surgery, just rehab exercises. These ligaments give your knee its integral stability, with your ACL stopping your shin bone moving forward on your thigh bone. Below is a picture of a flexed right knee with the kneecap removed. You can see the ACL lying in front of the PCL like a cross, hence the term cruciate.

Historically it was a career ending injury but due to surgical advances, the ACL can now be reconstructed, giving athletes the opportunity to return to sport after surgery and a lengthy rehab which varies from 6-12 months.

How is the ACL injured?

50% of ACL injuries are non-contact, in a knee-in toe-out position, with your body pivoting above it, and the knee buckling inward. The force generated through the knee joint becomes too much for the ACL ligament to withstand and it ruptures. Michael Owen demonstrates it classically in the video below…

In sports such as American Football and Rugby however, the more common mechanism of injury of the ACL is through direct contact in a tackling situation. ACL injury can also occur when the knee is forcefully extended or on sudden deceleration.

Does every ACL injury require surgery?

Those with a partial tear of ACL i.e. a minor degree of ligament injury, and no functional instability can sometimes continue to play but may possibly require surgery down the line.

For those with a full ACL tear and an ambition to return to field sports, surgery is generally your best option. With surgery you are at a greater risk of early onset osteoarthritis, but this is somewhat dependent on amount of meniscal and articular cartilage damage in the initial injury.

Who is most at risk of ACL injury?

ACL injuries are more common in sports that involve high speed, sudden, rotational movements. Sports with a higher risk of ACL injury include Soccer, American Football, Basketball, Rugby, Aussie Rules, GAA, and Skiing.

Female athletes are 2-8 times more likely to have an ACL injury, argued to be related to;

1. 1) Landing strategies that place greater load through their knees

i.e. landing with a more upright posture, less knee flexion, greater quad to hamstring ratio, and increased knee-in position

2. 2) A larger angle from the hip to the knee

3. 3) Hormonal changes that can decrease the inherent strength of ACL

4. 4) Smaller anatomical attachment for the ACL

Athletes with a reconstructed ACL (those who have had ACL surgery) are at a much greater risk of ACL injury, on both the operated and non-operated knee, than those without a history of ACL injury. Up to 25 % of athletes with reconstructed ACLs go on to have a second ACL injury within 6 years.

Gaelic football shares numerous similarities with Aussie Rules which allow for some comparison with their injury data. A large study on Aussie Rules footballers over 8 seasons found the past ACL reconstruction was the strongest predictor of another ACL injury. Within the first 12 months post ACL reconstruction, their athletes were at a 10 fold increased risk of ACL injury. Beyond 12 months they were still at a 4 fold increased risk, in both their operated and non-operated knees.

Can we predict who is most likely to get a second ACL injury?

A second ACL injury seems to be strongly related to individual biomechanical abnormalities and movement asymmetries. This means how well you co-ordinate and control your movement as you jump, hop and land. One study found that compensatory strategies in the opposite hip, on landing, were the primary predictor of risk in athletes who went on to develop a second ACL injury. Recent research has also provided us with four measures to help predict who is most likely to re-injure their reconstructed ACL.

The American Journal of Sports Medicine looked at predictors of failure rate after ACL reconstruction in 206 subjects over 2 years. There was a 13% graft failure rate with a higher rate of failure in those of; younger age 19-25, earlier return to sport (222 Vs 267 days), higher BMI and return to high risk sports.

We don’t have enough baseline data on re-rupture rate in GAA but across other sports ACL re-injury rate appears to be equal, suggesting that a second ACL injury may be more individually specific than sport specific.

Does the type of graft used affect re-rupture rate?

There is no difference in terms of ACL re-injury rate of hamstring vs patellar tendon graft. However, there is a difference between autograft (graft from your own body) Vs allograft (donor graft), with a higher rate of failure in those younger than 20 years who receive an allograft.

Is it possible to decrease your risk of ACL injury?

Yes. There is mounting evidence that those partaking high risk sports can decrease their risk of ACL injury, by regularly completing a series of warm-up programmes that encourage neuromuscular training and balance activities. FIFA and Women’s soccer associations have led the way in ACL prevention programs. Ideally we need to be able to identify those most at risk of injury and then target prevention programs at these athletes.

Do blades on your boots increase your risk of ACL injury?

There is conflicting evidence in relation to blades versus studs and associated injury risk. Blades were originally designed to offer more stability to the support foot in kicking in soccer, made famous in the mid-90s by a certain David Beckham. Due to their claims and some evidence of them giving more grip on the playing surface it has been argued that they can contribute to injuries.

A study on 15 professional soccer players comparing two types of both studded and blade soccer boots found no significant difference on knee loading. Increased knee loading forces have been indicated as a risk factor for knee and ACL injuries.

There is one study that looked at numerous top level European soccer surfaces and found that blades were associated with significantly higher rotational torques than studs, on natural grass only. Authors reported the studs were “probably safer” however these results must be interpreted with caution as it was a laboratory study, showing blades were associated with higher torque values but no correlation was made with injury prevalence.

Does the playing surface or weather conditions affect your risk of ACL injury?

Research, again from Aussie Rules injury database has found a significant increase in ACL injury rate in weather conditions associated with a drier playing surface; specifically a higher water evaporation rate and lower rainfall. However this research finding might not have as much applicability to Irish weather and GAA pitches…

It gets a bit more complicated and speculative when we look at pitch surfaces and artificial versus natural grass. Specific to ACL injuries, a study on natural grass surfaces in Australia found fewer ACL injuries on Rye grass surfaces compared to Bermuda grass surfaces.

Increased rotational torque has been identified as a small possible risk factor for lower limb injury but not specifically for ACL injury. A study on football turf used for top-level European soccer showed that football turf without infill showed significantly lower frictional torques than natural grass, whereas football turf with sand or rubber infill had significantly higher torques. But again, this was laboratory testing only and not specific to injury incidence, just related to one of the factors that is sometimes associated with lower limb injury. Clear as mud.

ACL injuries per sport

Below is a table which compares the percentage of ACL injuries in a given sport relative to all injuries in that sport. There are many issues with comparing sports injury data; however it does give us an indication of ACL injuries compared to all other injuries in that sport. Ideally we would like to compare injury incidence per 1000 player-hours, separated across match and training hours but as of yet that data is lacking.

As discussed, ACL injury is not unique to the GAA. If you play a sport that involves high speed, sudden, rotational movements, then yes, you are at a higher risk of ACL injury than the general population. However, the risk of ACL injury should not be seen as a deterrent for sports participation as the benefits of sport far outweigh the risks!

Please do not hesitate to contact us if you would like more information or advice on this topic.

Michelle Biggins
Chartered Physiotherapist
085-1670574
charteredphysio@gmail.com