Understanding and managing athletic groin pain

Athletic groin pain (AGP) is a confusing construct, encompassing many different structures in the hip and groin area. This chronic pain often occurs in multidirectional sports like Gaelic soccer, soccer, ice hockey, or handball. The incidence in male soccer players is between 0.2 – 2.1 per  1000 hours of play, and 0.1 – 0.6 per 1000 hours for female soccer players.

AGP is an umbrella term for a chronic overload in the hip-pelvis region resulting in pain beyond the “normal” levels, extent and duration of hip or groin pain in athletes.

Each tissue has an anatomical and biomechanical functional envelope or margin of tolerance. This margin is influenced by training load, genetics, biomechanical deviation (technique, load sharing), and other factors like structural capacity, psychosocial effects and muscle rebuilding / remodeling capacity. Exceeding this buffer over relatively long amounts of time can lead to subtle tissue overload, resulting in the development of dysfunctions like AGP.

The lack of sufficient time off for recovery and regeneration underlies the dilemma for athletes and practitioners to mitigate AGP. Athletes may complain initially about pain and stiffness, but there is no substantial loss of performance that would lead to them missing training or competition. This subacute phase continues until the pain and stiffness does not go away, and then begins to interfere with performance and availability.

Off season or preseason screening for groin muscle function is great, but warding off AGP requires a regular monitoring approach. Throughout the season, we want to quantify players’ ability and willingness to produce power through the groin muscles.

We try to follow a test-train approach to make our monitoring “invisible” to the players. Team strength training on the morning of MD-4 (MD+3) is our best opportunity to test the players.

One of the simplest tests to perform regularly in season or during the rehab process is the Copenhagen 5 second squeeze test^[3]. The Copenhagen test is becoming more popular, the downside of which means it’s probably being misused or misinterpreted at scale.

Advantages and limitations of the Copenhagen adductor test

The squeeze test was originally developed to provoke symptoms of groin dysfunction, rather than as a measure of adductor strength. It is not a proper measure of strength, asymmetry nor injury prediction. We have to be cautious and critical, and bear this fact in mind. Taking the test as a measure of strength, we could use it for interlimb and interindividual comparisons. But absolute adduction force does not provide a valid comparison between athletes across ranges of body composition. Relative force (N/kg) and, even more so, torque (N*m/kg) should be the standard unit of measurement for hip adduction strength.

Weak adductors relative to abductors (0.8 ratio) are a risk factor for AGP, so we want to be able to test both muscle groups. During the return to play process after AGP, the objective is to restore a balance (1 – 1.1) between the adductors and abductors ^[4,5].

The squeeze test does not permit a valid interlimb comparison because of the bilateral deficit. Especially in the rehab process, practitioners need to test unilateral hip adductor strength along with the bilateral and squeeze variations.

Overall, the Copenhagen squeeze test is practical and simple as well as sensitive for determining AGP related complaints, despite these limitations.

We use the Force Frame to capture the hip / groin symptoms (pain 0-10), absolute and relative adductor / abductor peak force, and adductor:abductor ratio.

Based on our preseason benchmarks, we set an 85% “alert threshold” that players must meet or exceed weekly. Moreover, regular standardized testing means we can determine weekly intra- and interpersonal deviations.

Benchmark	Peak force (N)	Relative peak force (N/kg)	85% threshold	Adductor : abductor ratio
Adduction squeeze short ForceFrame (60°) – Pre-season 2023/2024
Expected minimum	460	5.8	391	Low = 0.8 High = 1.2
Excellent	600	7.7	510	1 – 1.1
Adduction squeeze long ForceFrame (ankle) – Pre-season 2023/2024
Expected minimum	232	3.1	197	Low = 0.8 High = 1.2
Excellent	315	4.2	268	1 – 1.1
Adduction squeeze short HHD (60°) – Pre-season 2022/2023
Expected minimum	293	3.7	249	Low = 0.8 High = 1.2
Excellent	380	4.9	323	1 – 1.1
Adduction squeeze long HHD (ankle) – Pre-season 2022/2023
Expected minimum	160	2.1	136	Low = 0.8 High = 1.2
Excellent	280	3.7	238	1 – 1.1

Deviations >15% from the peak force, or players reporting groin pain intensity as 6 or more on a 0-10 scale during the Copenhagen squeeze test, experience substantially impaired sports related hip and groin function. These red flags result in a retest plus a short medical check. When strength is restored or the pain decreases, the player can train without issues. If the red flags persist, we must adjust or stop the player’s training to determine the appropriate intervention^[6].

Athletic groin pain prevention strategies

What if the pain or strength deficit remain? What is the AGP management approach?

When an otherwise healthy football player (a) complains of pain in the adductor longus insertion when sprinting and changing direction, (b) clinical tests reveal groin pain above the threshold of 6 out of 10, and (c) force during the squeeze test declines 30%, we need to decide whether to take a surgical or non-surgical approach.

For a non-surgical approach, we subsequently establish the biomechanical diagnosis (e.g., movement or technique errors), physical capacities, context (workload) and clinical entity.

This is more productive than attempting to isolate or localize individual pathological structures clinically.

The key principles of a holistic AGP management approach are:

– multimodal,

– exercise movements and muscles,

– build resilience and capacity: robustness is key,

– biomechanics that are robust under linear and multidirectional loads,

– lumbopelvic control and integrity,

– load management,

– evidence based KPIs.

The rehab performance model has four successive phases with KPIs and exit criteria.

Phase 1: Intersegmental control and strength

Phil Glasgow uses the phrase “it is all about mechanotherapy,” so we must be specific in applying the optimal loading to the precise tissue. We must find the sweet spot between non-functional, tissue specific exercises (such as loading the adductor longus) and intersegmental strength exercises for whole system load^[9]. Traditional strength exercises like squat, lunge and side lunge are not great exercises for adductor longus load.

Peak hip adductor muscle activity during selective exercises^[9]:

ISO squeeze short

Copenhagen

Standing ADD with elastic

Hip ADD machine

ISO squeeze long

Isometric exercises can be a valuable tool to set a highly specific biopositive stress. Despite pain and irritation, high load low jerk isometrics can be used with few issues. Isometrics also induce an analgesic effect with a reduction in muscular inhibition, which allows the athlete to increase the tissue specific capacity.

Practitioners should be on guard against the tunnel vision that hinders us from considering and seeing the full context of muscle interaction, particularly in a structure like the hip. The interaction of all the muscles surrounding the hip enables intermuscular load sharing. Energy can be distributed intersegmentally and intermuscularly. An optimal relationship between the hip muscles should look something like an extensor:flexor:adductor:abductor relationship of 100:90:80:60. 

Phase 1: Intersegmental control strength

KPIs:

Parameter:

Pain 0/10 – Walking, bike, 1.5 x BW 6 min

Phase 1 drills: Step up, deadlift, RDL, squats, hip flexion/extension/abduction/adduction, extensive ankling/pogos

Crossover test negative (passive extension/adduction)

Phase 2: Return to linear running

Training physical capacities in isolation in Phase 1 is often not enough to change movement patterns or techniques, but are necessary to improve physical abilities (e.g., more strength) and establish the basis for executing movement patterns. The greater the capacity, the more degrees of freedom, the more movement solutions are available. Stronger athletes tend to have high movement variability that unlock flexible movement solutions compared to weaker athletes who have fewer and more rigid movement patterns.

The motor calibration of the newly (re)gained capacity is of immense importance.

This process can be facilitated mainly by exploratory learning conditions (differential learning). Motor constraints force the athlete to translate the improved muscle strength into productive movement strategies^[10].

The objective of this phase is to return to running and improve intersegmental control during linear running mechanics drills. Drills that force the athlete to counteract anterior pelvic tilt, to stay tall, and to keep the hip locked during switching and skipping drills are essential. The hip lock along with swing leg retraction are two of the main building blocks for reflex based movement attractors like the crossed extensor reflex and stumble reflex.

Phase 2: Return to linear running

KPIs:

Parameter:

Phase 2 linear running mechanics drills pain free

Strength deficit <15% squeeze test and single leg adduction (3xBW)

Squeeze test pain levels <3

Bilateral CMJ, LSI >85%, LSI impulse height, eccentric rate of force development, impulse <20%

2 km running 10 min, HSR Box-Box 12″ 4x (19.8 – 25 km/h)

Marching, skipping, overhead drills, resisted elastic drills, step up variations

Phase 3: Return to progressive running

The aim of this next phase is to progress and intensify the linear running intensity and improve intersegmental control during multidirectional drills. Practitioners need to create exercises and induce motor constraints that force the motor system to explore new movement solutions.

Lateral shuffles and planned 60° / 90° / 180° change of direction tasks with motor constraints (elastic band, overhead bar, medicine ball, water bag) represent effective exercises that challenge the whole lumbopelvic integrity and potentially improve the system stiffness. System stiffness, especially at the hip and ankle, are key pillars of performance and robustness^[11–13].

Phase 3: Return to progressive running and change of direction

KPIs:

Parameter:

Pain free squeeze short test >460N (5xBW); long >160N (2xBW); 1-1.1; single leg adduction <10%

Pain free linear running A program (high speed running, tempo runs)

Hip IR, BKFO, abduction symmetrical

30m sprint 80% max sprint speed, acceleration / deceleration / change of direction drills 80-90% intensity

Phase 3 multidirectional drills pain free

Bilateral and single leg jump drills 15 / 30cm, <250/200ms, RSI >2; 10-5 hop test

Lateral lunge 30% BW 10x, Copenhagen long dynamics 10x, reactive skater jumps, lateral shuffle

Phase 4: Return to sport and team training

The on field rehab bridges the gap between gym and team training. The objective of on field rehab is for the player to regain or exceed the chronic load prior to the AGP before returning to team training. This will ensure that the player is able to cope with the upcoming physical demands of team training upon return. Progressing the rehabilitation on field from high control to high chaos^[14] allows for a smooth transition to team training.

Due to limited resources and lack of consensus we must follow a pragmatic and heuristic approach. Athletes should regain or exceed pre-injury levels to build a buffer that can better mitigate potential load spikes. Additionally, aiming for limb symmetry is advantageous, as long as the weaker limb is moving in the direction of the stronger limb. The athlete must push the ceiling to get bulletproof hip muscles.

Addressing key elements like physical capacity, load management, biomechanics, and mental readiness allow us to build robustness and resilience to overcome and ultimately prevent AGP.

Phase 4: Return to sport/team training

KPIs:

Parameter:

30m Sprint 100% MSS (pre-AGP Benchmark)

ACC/DEC/CoD 90-180°/lateral shuffle at 100% Intensity

On field rehab training phase 1-5 symptom free

Palpation adductors, pubis, iliopsoas and inguinal ligament <1 on 0-10 pain scale

Load management: acute:chronic workload (1-2x match load)

Sport specific actions symptom free

Extension:flexion:adductor:abductor 100-90-80-60, optional MRI or ultrasound review, multidisciplinary team decision making