Kristian Thorborg is a Sports physiotherapist from Denmark who presented his thoughts and research on the Prevention of groin injuries in Sports.
As part of my “Performance and Injury” subject these concepts are summarized below:
Previously groin injuries were always thought to be hernias – the problem with this term is that with sports hernia is that no actual hernia exists and there is more abdominal related problems present. Kristian highlighted that there are so many different interpretations and labels given to groin pain depending on what part of the world you are practicing. This is where confusion is created in that the injury mechanisms become difficult to define due to variety of terminologies being used.
- Groin pain can be divided into 4 different Clinical entities:
- Adductor related
- Abdominal related
- Psoas related
- Hip related
Kristian then explained that it is difficult to diagnose groin pain but he believes they can be narrowed down to the 4 areas listed above. Referencing a study in soccer that he was involved with he outlined the % occurrence for each type with Adductor related groin pain being the most prominent (50-70%). Therefore, in working with athletes in soccer you could reasonably assume that clinical entity as a highly probable source of pain and appropriately test for it to confirm before proceeding with treatment.
Kristian went on to further discuss soccer & ice hockey where both abdominal (5-20%) and adductor (50-70%) related groin pain were the most prominent types of groin injuries occurring. It was also noted that when you have an abdominal injury then it adds to injury recovery time and hence takes longer to return to play. Specifically in Ice Hockey, muscle activity during skating stride consists of both concentric and eccentric work done by the adductors. The faster they skate the more muscle activity occurs and you increase skating speed by increasing your stride rate. It has also been highlighted in Ice Hockey that if there is a low adduction / abduction strength ratio then this increases hip adductor strain risk up to 17x. In particular, hip adduction strength asymmetry of >25% has also been shown to be related to adductor strain on the weak side. Another study by Emery et al in Canadian ice hockey players found that there was no increased risk in players with peak isometric adduction force. They couldn’t predict any injuries and did show as a risk for a groin strain.
- Risk Factors shown in the Literature in regards to Soccer, Ice Hockey and Rugby players are as follows:
- Previous Injury
- Weak adductors
- Decreased eccentric hip adductors to abductors strength ratio
- Groin injuries commonly occur to the adductors in the kicking leg.
By knowing the common risk factors then injury prevention programs should try to include the neuromuscular system which is highly plastic and can adapt very quickly when exposed to any stimuli. An effort should be made to increase eccentric muscle strength, rate of force development and maximal muscle strength. Exercise intensity also needs to be included with at least 60% 1RM needed according to ACSM guideline and 80-95% of 1RM for optimal hypertrophy.
In the Applied Environment?
- A four step injury prevention cycle was outlined in the presentation which could be implemented:
- Establishing the extent of injury – looking at both the incidence and severity.
- Establishing the aetiology & mechanisms
- Introduce Preventative measures
- Assessing effectiveness by repeating Step 1.
- By measuring hip adduction you can monitor muscle strength as a risk factor and implement treatment or exercises to reduce injury. There are 2 common ways of measuring hip adduction:
- A Squeeze test in between the knees to measure maximum force. The problem with this test is that maximal force will be limited by the weaker leg.
- A break test with dynometer on both the hip adductor and abductor. This is a useful test as it is unilateral in nature – testing one leg at a time for weakness.
- For the Neuromscular system the use of plyometric jumping exercises is recommended. They have been shown to increase the pre-activity of adductor muscles over 6 weeks with 2 sessions per week specifically using drop jumps.
- Isometric ball squeezes on the back with both bent and straight knees to improve strength.
- Hip adduction exercises with an elastic band program have been shown to improve Eccentric strength – 30% increase in conjunction with soccer training.
- Strengthening the abdominals: Swiss ball crunch is good for prevention in relation to abdominal groin injuries.
- Monitoring: Use of the HAGOS score developed by Thorborg. Based on Questionnaire with 6 separate scores that try to capture information on groin injuries of players still playing – Athletes often don’t get noticed until they actually miss training / game. It is good practice to capture how they are feeling while they are still playing.
- In a club scenario: It is difficult to introduce new interventions so the alternative is to monitor their loads to look out for injury risks. Then implement on an individual scale and monitor how the athlete responds to stimulus.
Only the tip of the iceberg – We must realise that many athletes show signs of groin injury but continue to train and play regardless. It may take long periods of time for the injury to manifest itself and by that time it may be too late for the athlete to avoid serious ramifications – i.e. surgery. So it is important to preparing the athlete for specific and repetitive loading whilst also monitoring load and overload to best protect the groin.