Updated: Apr 23, 2019
If you haven't read Part 1, we recommend starting there before reading this post. If you already have, then great! Let us continue on our path to learning about the adductors and groin pain.
How do we know if the adductors are causing our groin pain?
Since we are rehab professionals a couple assumptions will be made:
1. Someone is coming to see you for acute or chronic groin, hip, abdominal, or back pain.
2. We are trying to rule in or out whether an adductor strain has occurred.
It's best to start as broad as possible and then get more specific; understanding how adductor strains occur is the important first step.
How most adductor strains occur:
1. Blunt force trauma that results in swelling and bruising, such as someone kicking the inside of your leg.
2. Pain during a forceful muscle contraction: An example of this would be when the adductors actively decelerate the leg during extension and abduction (think bringing the leg back before kicking a soccer ball). Or a forceful eccentric to a concentric phase of muscle activation, such as a change in direction when sprinting. This is why having a good hip abduction to adduction strength ratio and training the adductors in an eccentric fashion is important.
3. Repetitive micro-trauma or prolonged low grade groin pain: This could be from overuse, poor lumbo-pelvic control, or repeated episodes of low grade trauma.
As an aside, adductor strains are more common in those who perform repetitive twisting, sprinting, kicking, and turning based activities. This is why soccer and hockey players are much more likely than our average human to incur a groin injury.
Other things to consider include the location of pain (pain can be referred from other areas, so it's not always a good indicator of tissue damage), any visible bruising over the site of injury, and activities that make the pain worse or better.
Range of motion, Palpation, and Manual Muscle Testing
When trying to determine if the patient's symptoms are muscular in nature, like with a strain, the use of manual muscle testing, palpation, and range of motion should corroborate the findings. Including all three in an exam will help narrow the diagnosis.
A video demonstrating assessment techniques for the adductors.
Considerations with Manual Muscle testing:
Adduction in 0 degrees of hip flexion ( think laying flat ) - the adductor magnus and longus may be more involved when compared to the other adductors.
Adduction in 45 degrees of hip flexion ( knees bent while laying flat ) - The adductor magnus, longus, and gracilis all show very high levels of EMG activity in this position.
Adduction in 90 degrees of hip flexion - This may preferentially target the pectineus more so than the other adductors. The pectineus has been shown to have high EMG activity during supine hip flexion as well.
Considerations when palpating:
The absence of pain during palpation of the adductors has the highest predictive value of ruling out an acute injury to these structures. If there is no pain upon palpation of the adductors, start looking elsewhere.
Considerations when assessing passive range of motion:
Just like with manual muscle testing, assessing passive hip abduction at 0, 45, and 90 degrees of hip flexion should be included in the exam. Limitations to passive range of motion, muscle guarding and pain are relevant findings.
What special testing should you be using?
When positive, the resisted outer range adduction test (first video), squeeze test (second video), and passive adduction stretch (first video) all have a probability of 80 - 81% for correctly predicting a positive MRI with regards to an adductor strain. This is high. In one study, each test was able to correctly determine the location of the strain as well.
All of the three tests listed above should be considered when performing an exam for an adductor strain.
Bruising and swelling along the adductor group. Activities that make the pain worse or better.
Your adductors are likely involved in your groin pain if...
1. The mechanism of injury involves a forceful contraction of the leg muscles such as kicking a ball or a quick change of direction.
2. There is pain with palpation of the adductors along the insertion, musculotendinous junction, or muscle belly.
3. Pain with special testing such as the adductor squeeze test, resisted outer range adduction test, or passive adduction stretch
4. Other secondary findings are present such as bruising and swelling along adductors.
We hope you enjoyed! Stay tuned for part three where we talk about rehab and training applications.