Paired TruStrength Mode Is Here

Bilateral Force in a Single Rep

Two units mean two synchronised, instrumented force channels. Where the original handheld dynamometer setup returns a single combined value, Paired TruStrength returns left, right, and total — independently — from one 5-second rep.

Every TruStrength metric is reported per side: Peak Force, Peak Net Force, Average Force, Total and Net Impulse, Peak Rate of Force Development (RFD), Time to Peak Force, Net Force at 50, 100, 150, 200, and 250 ms, and an Explosive Strength Index. Add per-metric Asymmetry % across the test and the whole bilateral picture is in front of you in seconds.

Live Left (orange) and Right (cyan) traces on screen during the rep. Save, and everything syncs to Hawkin Cloud for review and export.

The Long-Lever 0°/0° is the Recommended Primary Protocol — and the 45° and 90° Varients Are There Too

Paired Mode supports three supine adductor test positions. The long-lever 0° hip / 0° knee — the original Copenhagen 5SST geometry — is the recommended primary protocol. It is the position with the strongest published research underpinning across torque, test-retest reliability, and the ability to discriminate adductor-related groin pain from healthy presentations.

The 45° hip / 90° knee and 90° hip / 90° knee variants are also supported in Hawkin Capture, for length-tension profiling or where the long-lever position is not feasible for an athlete. For the variants, the units sit at the medial knee. The pad-to-pad distance stays fixed at 32.5 cm.

Each position should be distinguished by its own tag in Hawkin Capture. We recommend iso_groin_supine_0, iso_groin_supine_45, and iso_groin_supine_90 — so the data sorts cleanly across sessions and positions when pulled into Hawkin Cloud reports.

The Research Behind It

Three peer-reviewed studies underpin the long-lever Copenhagen 5SST methodology that Paired TruStrength delivers.

Light and Thorborg (2016) compared three adductor squeeze positions in elite footballers using a handheld dynamometer. The long-lever 0° hip / 0° knee position produced 69% more adductor torque than the traditional short-lever 45° squeeze in adduction, and 11% more than a 45° abduction/external-rotation variant. It was also the position with the highest test-retest precision of the three studied — ICC (intraclass correlation coefficient) = 0.97, with a minimal detectable change (MDC) of 6.6%. The conclusion was simple: of the squeeze positions used in the field, the long-lever position has the lowest measurement noise and the largest signal.

Drew and colleagues (2016) used an experimental pain model — hypertonic saline injected into the adductor longus tendon — to ask which squeeze position best detected adductor longus pain. Adduction at 0° hip flexion produced the highest positive likelihood ratio (+LR ≈ 2.8) and the best Receiver Operating Characteristic (ROC) area-under-curve of the three positions tested (0°, 45°, 90°). The authors concluded that the 0° test“optimises the diagnostic procedure without compromising diagnostic capacity to identify experimental adductor longus tendon pain.”

Wörner, Thorborg and Eek (2019) then took the long-lever 5SST out of the lab and into the field — applying it in 333 male professional and semi-professional ice hockey players. They demonstrated significant correlations between 5SST results, self-reported function on the Copenhagen Hip and Groin Outcome Score (HAGOS), and bilateral adduction strength.

Three studies. Three different angles on the same finding: the long-lever, partially abducted, 0° hip / 0° knee position is where bilateral adductor strength testing is at its most precise and most informative. Paired TruStrengthis engineered to deliver that protocol — fixed-geometry, bilateral, instrumented — without the practitioner-dependent variability that the published research had to live with.

How the 32.5 cm pad-to-pad distance maps onto the published methodology

In the published Copenhagen 5SST, the assessor’s forearm plus the handheld dynamometer sets the pad-to-pad distance — typically around 31–35 cm. The Hawkin clamp-mounted setup at 32.5 cm sits comfortably inside that range, so practitioners migrating from a handheld dynamometer keep the same long-lever, partially abducted geometry while gaining a fixed, repeatable distance — no variance from clinician arm length. The test setup is repeatable across testing days, between practitioners, and against the published norms.

What a Handheld Dynamometer Gives Up And What Paired TruStrength Fixes

The handheld dynamometer is the tool most practitioners reach for to run the long-lever 5SST in the field. It comes with five practical limitations everyone in the field already knows:

• The pad-to-pad distance is whatever the assessor’s forearm length happens to be, which reduces standardisation across multidisciplinary teams.

• The HHD records a single combined L+R force value from unilateral contributions, with no way to separate left and right force in a single rep.

• A clinician absorbs the squeeze for every athlete in the squad, and assessor fatigue can degrade data quality across a long testing day.

• Stopwatch-gated timing introduces variability into the test window.

• Handheld hynamometer calibration drifts over time.

Paired TruStrength addresses each one directly. The lever arm is the engineering, not the assessor — fixed at 32.5 cm and identical across multidisciplinary teams. The two units record left and right force independently, with a per-metric asymmetry index from a single rep, which saves you a second rep without losing the limb-by-limb force-time data. The units are clamped, so there is no squeeze load on the assessor and no fatigue-related drift in the data. The trigger is force-threshold-gated — the 5-second rep window starts the moment both units detect contact and ends precisely 5 seconds later, enforcing standardisation across reps and producing comparable impulse data. And TruStrength units carry traceable calibration that does not depend on the practitioner.

Real-World Applications

Paired Mode is already shipping with three practical use cases beyond the long-lever Copenhagen 5SST.

Standardise testing across the whole support team. The same setup, the same validated thresholds, the same protocol — running identically between practitioners, with less protocol variation in your data.

Train at known intensities, not by feel. Use the in-rep biofeedback in Hawkin Capture to run isometric training at known percentages of an athlete’s maximal effort, so the work hits the prescribed target rather than relying on perceived effort alone.

Run consistent multi-centre research. Large-sample, multi-centre research projects can now use bilateral adductor protocols with consistent methodology between sites, improving academic rigour in large-sample data collection.

What You Need

• Two Hawkin TruStrength units of the same generation (e.g., 2× Gen3), both running the latest Hawkin Capture–compatible firmware
• One Hawkin clamp mount
• A solid frame to mount onto — gym rack or secure vertical post (or similar)
• The Hawkin Capture app (iOS or Android)
• An active Hawkin Dynamics account

Paired TruStrength Mode is included at every tier for no additional cost. Existing customers receive it automatically as part of the Hawkin Capture release on 1 May 2026. No separate install, no firmware update.

Getting Started 

1. Open the Hawkin Capture app and tap Connect.
2. Select TruStrength as the device type, scan, and connect both units.
3. Assign one unit as LEFT and the other as RIGHT.
4. Mount both units on the clamp mount on a rack or post, set the height to suit the test position, and tighten the clamps so the units are hand-tight and not moving.
5. Position the athlete supine, hips and knees at 0°, legs extended and abducted to the pads.
6. Tap the record button and run a 5-second maximal contraction. Repeat for three reps.