Groin Strain

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Clinically Relevant Anatomy

A groin strain is a tear or rupture to any one of the adductor muscles. There are five adductor muscles, the pectineus, adductor brevis and adductor longus (called short adductors which go from the pelvis to the thigh bone) and the gracilis and adductor magnus (long adductors which go from the pelvis to the knee).

The main function of the adductors is to pull the legs back towards the midline, a movement called adduction. During normal walking they are used in pulling the swinging lower limb towards the middle to maintain balance. They are also used extensively in sprinting, playing football, horse riding, hurdling and any sport which requires fast changes in direction.


Mechanisim of Injury

A rupture or tear in the muscle usually occurs when sprinting, changing direction or in rapid movements of the leg against resistance such as kicking a ball. This is especially likely if a thorough warm-up has not been undertaken first! Repetitive overuse of the groin muscles may result in adductor tendinopathy.

 Classification of groin strains – Grade 1, 2 or 3?

Groin strains, as with all muscle tears, are graded 1, 2, or 3 depending on how bad they are. Grade one is a minor tear where less than 10% of fibres are damaged. Grade 2 is a moderate tear and can be anything from 10 to 90% of fibres torn. For this reason, grade 2 injuries are often termed 2+ or 2-. Grade 3 injuries are the most serious being either partial or full ruptures.


Characteristics and Clinical presentation

Grade 1

  • Discomfort in the groin or inner thigh. This may not be noticed until after exercise stops.
  • The groin muscles will usually feel tight.
  • There may be an area which is tender to touch
  • Walking is normal, discomfort may only be when running or even just on changes in direction.


Grade 2

  • A sudden sharp pain in the groin area or adductor muscles during exercise.
  • Tightening of the groin muscles that may not be present until the following day.
  • There may be minor bruising or swelling (this might not occur until a couple of days after the initial injury).
  • Weakness and possibly pain on contracting the adductor muscles (squeeze your legs together).
  • Discomfort or pain on stretching the muscle.
  • Walking may be affected. Running is painful.


Grade 3

  • Severe pain during exercise, often on changing direction suddenly when sprinting.
  • Inability to contract the groin muscles (squeeze your legs together).
  • Substantial swelling and bruising on the inner thigh within 24 hours.
  • Pain on attempting to stretch the groin muscles.
  • It may be possible to feel a lump or gap in the muscles.


Differential diagnosis

  • Tendoperiostitis of the adductor groups or musculus rectus abdominis
  • Osteitis Pubis
  • Entrapment of the nervus ilioinguinalis, nervus
  • Genitofemoralis or nervus obturatorius,
  • Avulsion or stress fractures of the lumbal spine, sacroiliac, or hip joints
  • Occult hernia (in undiagnosed chronic groin pain)

Kluin et al (2004)

Mechanism Of Injury and Differential Diagnosis

Muscle strain 

  • Sudden onset of pain following large muscle contraction/contusion or force.
  • Often running,jumping, sport.
  • Pain on contraction of muscle, weakness, tenderness over site of tear.

Osteitis Pubis

  • Result of repetitive trauma.
  • C/o pain in pubic symphysis region.
  • Pain with kicking, running, jumping, twisting.
  • Seen in swimmers/runners/lacrosse players.


Pain in the hip can be referred from the back, hip, SIJ or less commonly the knee therefore these must all be cleared for other pathology.

BACK                         HIP                     KNEE



General advice for patient

  • Apply Relative rest, compression and elevation.
  • Use crutches if needed.
  • Gently stretch the groin muscles provided this is comfortable to do so.
  • See a sports injury professional who can advise on rehabilitation of the injury.
  • For a suspected grade 3 strain seek professional help immediately.

Healthcare professional or Physiotherapy management

  • Use ultrasound or laser treatment.
  • Tape the groin to take the pressure off the area.
  • Biomechanical assessment to see if the adductors are being over worked predisposing them to injury.
  • Use sports massage techniques after the acute phase. This is extremely important.
  • Operate if the muscle has torn completely.
  • Advise on a rehabilitation programme consisting of stretching and strengthening exercises




This is by no means an extensive literature review and offers a glimpse at the ideas that are currently circulating in the medical world. As a student it it is tempting to read the summaries and not the full text. You will build your foundations and understanding by reading the full article gaining the skills to understand scientific language and understand research which will save you a lot of time in your 3rd year when you will need to utilise these skills to maintain good quality within your dissertation.

Outcome of Conservative Management of Athletic Chronic Groin Injury Diagnosed as Pubic Bone Stress Injury (2007)

  •  Complete rest from weightbearing activities (running and walking) is needed to recover from this injury (pubic bone stress injury).
  • Researchers allowed stationary cycling and swimming to be commenced at an early point in our treatment program.
  • Muscle strengthening and core stability program This was prescribed by the treating therapist with no standardised treatment. This is a limitation of the study because it becomes difficult to attribute improvements to one specific program)
  • One of the pitfalls of treating chronic groin injury conservatively is that athletes will often attempt to train (run) when they feel even slightly improved, and this can be one of the reasons why a conservative (rest) program may fail.
  • Rested from running for 12 weeks (Read Appendix 2 for the rehabilitation protocol used).
  • Limitations of this study: Small sample size (30), Nil control group- therefore unable to say whether shorter/longer rest/ different treatment would have given a better/worse result. Nil diagnostic criteria has not been fully validated yet.


Endoscopic evaluation and treatment of groin pain in the athlete.
Kluin J, den Hoed PT, van Linschoten R, IJzerman JC, van Steensel CJ.
Am J Sports Med. 2004 Jun;32(4):944-9.

Endoscopic evaluation and treatment of groin pain in the athlete.
Kluin J, den Hoed PT, van Linschoten R, IJzerman JC, van Steensel CJ.
Am J Sports Med. 2004 Jun;32(4):944-9.

Groin Injuries and Groin Pain in Athletes: Part 1 Review Article
Primary Care: Clinics in Office PracticeVolume 32, Issue 1March 2005Pages 163-183
Vincent Morelli, Victor Weaver

Groin injuries and groin pain in athletespart 2.
Morelli V, Espinoza L.
Prim Care. 2005 Mar;32(1):185-200.

Imaging of Groin Pain Review Article
Magnetic Resonance Imaging Clinics of North AmericaVolume 17, Issue 4November 2009Pages 655-666

Hip joint range of motion restriction precedes athletic chronic groin injury
Journal of Science and Medicine in SportVolume 10, Issue 6December 2007Pages 463-466
Geoffrey M. Verrall, John P. Slavotinek, Peter G. Barnes, Adrian Esterman, Roger D. Oakeshott, Anthony J. Spriggins

Manual or exercise therapy for long-standing adductor-related groin pain: A randomised controlled clinical trial Original Research Article
Manual TherapyVolume 16, Issue 2April 2011Pages 148-154

Physiotherapy for groin pain
Journal of Bodywork and Movement TherapiesVolume 2, Issue 3July 1998Pages 134-139
P. Newton

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