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GS Analyser 

Injury Prevention in Football

At GS we understand that Injury prevention in association football is crucial to the success of the team and the club as a whole.  For the individual, injuries can be career threatening.  For this reason, it is essential that clubs invest in effective injury prevention strategies

Through the work GS have completed within premier league football and the growing body of research, it is suggested that knee injuries are the most common form of injury with Anterior Cruciate Ligament injuries causing significant morbidity and seasons to end prematurely.  Hamstring injuries are another significant cause of morbidity amongst football players. 


Increasingly, we are seeing an increased awareness of concussion in football.  This was brought to the world’s attention when Loris Karius was Concussed during the 2017-18 Champions League Final


What the GS Analyser can offer you?

Soccer Players


Screen you players for weakness and muscular imbalances that may predispose to injury.  Our portable and versatile system means you can test at a location suitable for you and your players.



Offering unparalleled accuracy and versatility, examine the quadriceps/hamstring ratios of your players in no time at all.



Neck strength and concussion risk go hand in hand.  For every 1 lb increase in neck strength, your risk of concussion drops by 5%.  Safety and effectively test your teams neck strength and target those at risk.



Groin injuries in football are common.  The GSA can provide data on individual adductor peak force and fatigue rating.  Define your adductor rehabilitation with specialised groin rehab templates.


Screening for your players


Preseason strength testing allows team strength and conditioning staff to identify athletes with strength deficits and facilitates the implementation of targeted strengthening programs well before the athlete engages in the competitive season, thereby maximising performance and minimising injury risk.

The GS Analyser offers a groundbreaking new solution.  Test any muscle group, anywhere, anytime using our lightweight and portable GS Analyser. The analysis suite will highlight any strength deficits and abnormal ratios which may predispose to injury.  This data will facilitate and inform strengthening programmes.  Re-test your athletes to ensure resolution of weaknesses and imbalances.  The GS Analysis Suite will retrieve previous testing for immediate comparison.


ACL injury prevention

Knee injuries in football are the most common, especially those to the anterior or posterior cruciate ligament (ACL/PCL) and to the menisci (cartilage of the knee). These knee injuries can adversely affect a player's longterm involvement in the sport. 

Many modifiable factors can predispose to ACL injury.  Many studies have highlighted that hamstring strength imbalances and abnormal hamstring/quadriceps ratios pose a significant risk factor in ACL injuries.  With the GS Analyser, perform hamstring/quadriceps testing in seconds and identify players that are a greater risk!

Dynamic knee valgus during landings is associated with an increased risk of non-contact ACL injury.  We have found that peak isometric hamstring strength can vary according to foot positioning (tibial internal/external rotation).  If your hamstring is in the weaker position, it risks becoming actively overloaded with forces being transmitted to the passive structures and risking ACL rupture.  The versatility of the GS Analyser allows you to test your athletes in these positions.

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ACL Prevention

Hamstring profiling

Quadriceps profiling

The GS Analyser offers detailed Hamstring and Quadriceps analysis in a variety of different positions including:  Prone and sitting.  In addition, each test can be performed with either tibial internal rotation, tibial external rotation or in neutral position.  Why is this relevant?  The multitude of individual muscles which constitute the hamstrings and quadriceps will work optimumly in different positions.  

In the prone position (hip at 0° and knee at 90°) the hamstrings generate less force, than in seated position.  The hamstring fibres from the ischial tuberosity in this position are not in their optimum range but shortened and do not generate a maximal peak force.  This position will primarily load the short head of bicep.

In the seated position (hip at 90° and knee at 90°) the ischial fibres are optimised and will generate a greater peak force.  This position will primarily load the ischial fibres of the hamstring groups.  Identification of these positional variants of peak force production will facilitate safe and appropriate loading for rehabilitation and return to play strategies. 

In the prone position (i.e. Hip at 0° and knee at 90°), the rectus fermoris, which acts over the hip and the knee will be recruited and tested maximally as part of the quadriceps group.  This is in contrast to the sitting position (hip at 90° and knee at 90°) where the vastus lateralis, medialis and intermedius, which only act over the knee, are primarily tested maximally.  This allows us to identify and monitor rectus femoris lesions.


A video of quadriceps testing.  An example of knee extension in the seated position.  In this example, the GSA is attached to a fixed point, as opposed to user controlled which relies on eccentric overloading.  An example of the versatility of the system.

In summary the GSA can offer you:

  1. Detailed and high resolution quadriceps/hamstring profiling:

    • Peak force​

    • Fatigue rating

    • H/Q ratio assessment (Hamstring/Quadriceps)

  2. Quick and accurate assessment of quadriceps/hamstring bilateral status and identifying potential markers to injury e.g. asymmetrical fatigue ratings/muscle imbalances.

  3. Baseline profiles of your teams and an objective measure to gauge progress of muscle strength and condition.

Concussion prevention

Concussion prevention

Football players are particularly susceptible to concussion. A concussion results in a change in mental state due to a traumatic impact to the head. Not all those who suffer a concussion will lose consciousness. Some symptoms and signs that a concussion has been sustained are headache, dizziness, nausea, loss of balance, drowsiness, numbness/tingling, difficulty concentrating, and blurry vision. The athlete should return to play only when clearance is granted by a health care professional.

Research has shown that neck strengthening is crucial in concussion prevention.  Collins et al published a study in 2014 which demonstrated that with every pound/half kg increase in neck strength, the odds of concussion decreased by 5%.

Unlike anything seen before, the GS Analyser offers the ability to safely and accurately assess neck strength.  Screen your player's neck strength and identify those at a greater risk of concussion.  Furthermore, we offer a proven intervention - the GS Harness as an effective neck strengthening tool.

Working with Professor Hamish Kerr of Albany University, New York, we have been conducting research using the GSA to assess neck strength in the management of return to play after sports-related concussions (SRC).  The study on the right was presented to the American Medical Society for Sports Medicine in April 2018 which was well received.  Professor Kerr has been successful in receiving a grant to continue with this work in United States using the GSA.

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Groin injury prevention & rehabilitation 

Assess your athletes adductor function like never before.  The GSA provides you with the ability to determine peak bilateral isometric force (Adductor Squeeze test) AND the ability to profile the left and the right adductors individually.  Assess adductor fatigue rating and perform defined and controlled rehabilitation using our various rehabilitation templates. 

Adductor peak force

To define the adductor profile, it is essential to test each leg separately to identify any peak force or fatigue rating deficits.  This can not be identified with a "squeeze test" which does not differentiate between the two sides.  Maximal force generation from the "squeeze test" will be defined by the action of the undefined weaker side.

By defining the weaker side, we can safely target force loading in both individual actions and combined actions such as squeeze test training.


Current trends of rehabilitation involves using the squeeze test at the knee, using a short lever.  This is not wholly representative of football as one does not kick a ball from the knee, but from the foot which is a long lever.  Consequently, a different force.  With the GSA, we assess adductor function at the knee and more importantly, the foot (see video on right)

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Adductor Squeeze test

Left adductor peak force test.  Position of right leg locking pelvis

Adductor fatigue

The adductor group are a very delicate set of muscles.  Particularly the short fibres are subject to stress injuries.  Fatigue testing can be safely carried out at 30% of the one-rep max which will avoid injury.  

 By screening adductor fatigue profiles of your team, you can identify players at risk of adductor injuries with reduce fatigue profiles and muscle imbalances.

Adductor fatigue testing.  Sustaining a adductor squeeze at 30% one-rep max for as long as possible.

Adductor rehabilitation

Adductor training must involve training not just at the knee, but more importantly at the ankle.  It is also critical to have variations in rates of force development, for example, the differentiation between running and the sudden impact of kicking the ball.  These must be included in your rehabilitation programme to avoid further injury and success return to play.  Our system has exercise templates that incorporates these variants in rate of force development (see video on the right).

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