Adductor Squeeze Return Readiness: Symmetry Criteria After Groin Strain

A grade 2 adductor longus strain sidelines a college soccer midfielder for five weeks. At the week-4 checkpoint, the athletic trainer inflates a blood pressure cuff between his knees, has him squeeze, and reads back a number: 180 mmHg. He asks the obvious question, is that good? Nobody in the room actually knows, because 180 mmHg means something different for a 58 kg winger than for a 90 kg center back, and neither the trainer's reference sheet nor last year's team screening printout gives one cutoff that fairly applies to both bodies.

That is the trap that swallows a lot of well-intentioned return-to-sport calls after groin strain: chasing a generic normative squeeze value instead of comparing the injured hip against the one dataset that actually matters for this athlete, his own uninjured side, tested the same way, on the same day. Groin strains carry one of the higher reinjury rates in field and court sport, largely because clearance gets decided off pain resolution and a single squeeze reading rather than a tracked symmetry trend paired with exactly where and at what load pain reappears.

This guide sets out a squeeze-test protocol built around two numbers that travel with the athlete regardless of body size or sport: the side-to-side limb symmetry percentage, and the pain response at each hip-flexion angle tested. Combined with the broader battery covered in our return-to-sport protocol guide, they replace the absolute-force chase with a criterion specific to the one hip that actually got hurt.

The adductor squeeze test loads the hip adductors isometrically at three flexion angles, and each angle stresses a different part of the muscle group and reproduces pain differently depending on which structure is actually involved. At 0 degrees, the athlete lies supine with legs straight and squeezes against resistance at the ankles; this position most reliably reproduces pain from an adductor longus strain because the muscle sits closer to end-range length there. At 45 degrees, knees bent and feet flat on the table, load shifts toward the mid-belly of the adductor group. At 90 degrees, knees pulled toward the chest, the test brings iliopsoas and pubic-region structures more into the picture, which helps separate a straightforward strain from an athletic pubalgia presentation that squeeze testing alone will not fully rule out.

Standardize equipment before comparing anything across sessions. A sphygmomanometer cuff pre-inflated to a 10 mmHg baseline, placed between the knees or ankles depending on the angle being tested, gives a cheap and widely used reading: have the athlete produce a maximal 5-second squeeze, record peak pressure, then subtract the 10 mmHg baseline to get the true squeeze value. A handheld dynamometer strapped at the same landmark works just as well and reports directly in kilograms-force or newtons. The exact device matters less than using the same device, the same landmark, and the same 5-second hold on every retest. Run three trials per position with 60 seconds of rest between them, test the uninjured side first to set that session's reference, then test the injured side, and log the best of the three trials at each position and each side.

Three studies frame what a squeeze-test reading can and cannot tell a clinician, and each carries a real limitation worth knowing before anyone treats a single number as gospel.

Delahunt, Fitzpatrick, and Blake (2011), in the Journal of Science and Medicine in Sport, tested the squeeze test's reliability across all three hip-flexion angles in male inter-county Gaelic games athletes. Test-retest reliability came back excellent at every angle, with intraclass correlation coefficients running roughly 0.85 to 0.93, and the authors calculated a minimal detectable change for each position, meaning a session-to-session shift smaller than that figure could just be measurement noise rather than a real change in the athlete's hip. The limitation: the sample was small, around two dozen athletes, and every one of them was healthy and uninjured at the time of testing. The study proves the measurement itself is repeatable enough to trend; it says nothing about what a given reading, or change, means for an athlete actually recovering from a strain.

Thorborg, Branci, Stensbirk, Jensen, and Hölmich (2017), in the British Journal of Sports Medicine, validated a standardized 5-second squeeze protocol at 0 degrees against the Hip and Groin Outcome Score in elite soccer players. Squeeze force correlated with self-reported hip and groin function at a moderate level, with reliability across sessions again strong. The limitation sits in that word moderate: a moderate correlation means squeeze force explains only part of how an athlete's hip actually functions day to day, so a good squeeze number cannot stand in for asking the athlete directly whether the hip feels ready under sport-specific load.

The clearest signal on asymmetry itself comes from Thorborg, Branci, Nielsen, Tang, Nielsen, and Hölmich (2014), in the Orthopaedic Journal of Sports Medicine, comparing isometric hip adduction strength between soccer players with current adductor-related groin pain and players with none. The pain-free group showed close to symmetrical strength between their two hips, as expected. The group with current groin pain showed a clear, measurable deficit on the symptomatic side relative to their own uninjured side, a gap that simply was not present in the comparison group. That is direct evidence that a real interlimb asymmetry accompanies active groin pain, not just a coincidence of testing variability. The limitation: this was a single time-point comparison, not a tracked return-to-sport cohort, so it cannot tell a clinician what specific percentage deficit at the point of clearance predicts a safe return versus a reinjury.

None of those three studies hands a clinician a single percentage that clears an athlete, which is exactly why the decision has to run on this athlete's own limb symmetry trend plus where and how strongly the squeeze reproduces pain, rather than on a figure borrowed from someone else's normative table.

Calculate the limb symmetry index the way return-to-sport testing does elsewhere: (injured-side value divided by uninjured-side value) multiplied by 100. A reading of 92% at a given angle means an 8% deficit, and that percentage, not the raw mmHg or kilogram figure, is what belongs on the weekly tracking sheet at all three flexion angles, alongside a plain 0-to-10 pain score reported at the moment of peak squeeze. Pain reproduced at 0 degrees carries more weight than pain only at 90 degrees, since the extended position is the more specific provocation for the adductor longus strains that make up most of this injury category.

None of the three studies above validated these exact bands prospectively against reinjury in groin-strain athletes specifically. They borrow the general 10-15% asymmetry convention used broadly across return-to-sport literature and pair it with the reliability data above, which suggests a change smaller than roughly 5-8 percentage points at a given angle may just be test noise rather than a real shift. Treat the table as a structured field decision framework built from the best available reliability and asymmetry evidence, not as a single peer-reviewed cutoff.

Back to the midfielder from the opening example. At the week-6 checkpoint, squeeze symmetry comes back at 91% at 0 degrees, 94% at 45, and 96% at 90, all pain-free. On paper that clears the under-10% band easily. But the on-field return-to-sprint session that same afternoon produces a 3-out-of-10 pull sensation during a 45-degree cutting drill at 80% effort, something the squeeze test, performed lying still on a table, was never going to catch. He does not get cleared that day. The squeeze number was genuinely good; it just was not the whole picture, because an isometric test at rest cannot reproduce the eccentric, high-velocity loading a cutting movement puts through the adductor group, a gap covered from the sprint-mechanics side in our stride asymmetry wearable guide.

That gap is the practical argument for treating squeeze-test symmetry as one input into a broader return-to-sport decision rather than the finish line. Pair it with a progressive on-field loading sequence, straight-line running first, then curved running, then cutting at increasing intensity, and require the athlete to stay pain-free through each stage before advancing, on top of clearing the squeeze-test bands above. The most common mistake at this stage is testing only the 0-degree position and skipping 45 and 90 because the full sequence takes longer; a deficit that shows up only at one angle gets missed entirely if the other two never get tested, and it is usually the 90-degree reading that catches a lingering issue closer to the pubic symphysis rather than the muscle belly itself.

Retest weekly through an active return-to-run progression, always at the same time of day relative to that day's training load, since testing right after a heavy adductor session will read low on both sides and can mask a real asymmetry by dragging the healthy side's number down to meet the injured one. When the trend plateaus below the clearance band for three consecutive weekly checkpoints, or pain at 0 degrees reappears after previously resolving, route the athlete back to the treating clinician rather than continuing to adjust the loading program independently.