Proximal Hamstring — Phase Recommendations & Assessment

What is the LSI (Limb Symmetry Index)?
The LSI compares the strength of the injured leg to the uninjured leg and expresses it as a percentage: LSI (%) = (injured leg / uninjured leg) × 100. A score of 100% means both legs are equally strong. The LSI tells you how much strength has been recovered relative to the healthy side — and determines which rehabilitation phase a patient is ready for. All three test positions are measured separately, and the lowest LSI across all three is the one that determines the current phase.

Strength tests used for LSI

Test A
Hip extension — prone, hip 0°, knee 90°

Test B
Knee flexion — prone, knee 90°

Test C
Knee flexion — prone, knee 30° (proximal-specific)

Measured with handheld dynamometer (HHD) · Unit: N·m/kg · See Measurement Protocol tab for full instructions

Phase criteria

Phase 1

Initiate isotonic loading

~weeks 2–6

PainVAS ≤3/10 during submaximal isometric contraction (50–70%)

FunctionPain-free walking · tolerable single-leg bridging

StrengthNo formal LSI threshold — isometric contraction subjectively pain-free

SafetyNo combined hip flexion >70° + knee extension — stretch position prohibited throughout this phase

Phase 2

Initiate eccentric loading & jogging

~weeks 6–12

PainVAS ≤3/10 during functional tests and moderate jogging

Test ALSI hip extension ≥70%

Test BLSI knee flexion 90° ≥70%

Test CLSI knee flexion 30° ≥65% (proximal-load position — lower threshold acceptable early)

FunctionSymmetrical ROM · single-leg bridge tolerated · modified bent-knee test ≤3/10

Phase 3

Initiate plyometrics & running progressions

~weeks 12–20+

PainVAS ≤3/10 with all sport-specific loading

Test ALSI hip extension ≥80%

Test BLSI knee flexion 90° ≥80%

Test CLSI knee flexion 30° ≥75%

FunctionSingle-leg hop cluster LSI ≥80% · continuous running without symptom escalation

PHATScore ≥60/100

Phase 4

Return to sport

Proximal avulsion: typically ≥6 months

PainPain-free maximal manual testing · no symptom escalation >24h post-loading

Test ALSI hip extension ≥90%

Test BLSI knee flexion 90° ≥90%

Test CLSI knee flexion 30° ≥85%

FunctionSingle-leg hop cluster LSI ≥90%

PHATScore ≥75/100 (reference cohort median, Spoorendonk 2024)

EliteAll above + LSI ≥95% all tests + near-maximal sport-specific speed tolerated

LSI calculator

Test A — Hip extension (prone, knee 90°)

Injured leg (N·m/kg) Contralateral leg (N·m/kg)

— %

Ph2: ≥70%Ph3: ≥80%RTS: ≥90%

Test B — Knee flexion at 90°

Injured leg (N·m/kg) Contralateral leg (N·m/kg)

— %

Ph2: ≥70%Ph3: ≥80%RTS: ≥90%

Test C — Knee flexion at 30°

Injured leg (N·m/kg) Contralateral leg (N·m/kg)

— %

Ph2: ≥65%Ph3: ≥75%RTS: ≥85%

Current limiting phase

Enter values to see result

Lowest LSI across all tests determines the phase

Thresholds adapted from Spoorendonk et al. (2024 Orthop J Sports Med), Pihl et al. (2023 J Orthop Surg Res), Larson et al. (2022 IJSPT), and MGH non-operative hamstring protocol (2021).

Always use the same tester, same position, and same time of day across sessions. HHD strength measures have meaningful inter-rater variability — consistency of method is more important than absolute values.

General setup

Patient prone on a firm treatment table. Ask them to grip the sides of the table throughout all tests to stabilize the pelvis.
Conduct 3 maximal isometric efforts per test, each held for 5 seconds with ~10 seconds rest between. Record the highest value.
Discard and repeat any trial that differs by >20% from the other two.
Test the contralateral (uninjured) leg first, then the injured leg. Record force in Newtons and convert to N·m/kg (see formula at the bottom of this tab).
Verbal cue to patient: "Push as hard as you can and hold — don't let me move your leg." The clinician holds the dynamometer fixed throughout (isometric make-test — the leg does not actually move).

Test A — Hip extension · prone, hip 0°, knee 90°

Patient

Position

Fully prone · hip at 0° (neutral, no pillow under abdomen) · knee flexed to 90° · foot relaxed · arms along sides or gripping table edge

Instruction

On command, push your lower leg upward toward the ceiling (extending the hip) as hard as possible. Hold the push steady — do not let your pelvis rotate.

Clinician

Dynamometer placement

Pad on the posterior surface of the lower leg, approximately 5 cm above the medial malleolus · resistance direction: downward toward the table

Stabilisation

Stand beside the table in stride stance · elbows locked in extension to keep the dynamometer fixed · free hand on posterior iliac crest to prevent pelvis rising

Standard position used by Spoorendonk (2024) and Thorborg et al. (2010 SJMSS). Primarily loads gluteus maximus and hamstrings together as hip extensors. ICC 0.84–0.96 prone.

Test B — Knee flexion · prone, hip 0°, knee 90°

Patient

Position

Fully prone · hip at 0° · knee flexed to 90° · tibial rotation neutral · foot relaxed · gripping table edge

Instruction

On command, pull your heel toward your buttocks (flex the knee further) as hard as possible. Keep your thigh on the table — only the lower leg moves the force.

Clinician

Dynamometer placement

Pad on posterior lower leg, approximately 5 cm proximal to the lateral malleolus · resistance direction: downward toward the table

Stabilisation

Stride stance beside the table · elbows locked in extension · free hand applies light downward pressure on the posterior thigh to keep it on the table

Primary hamstring strength measure. Used in Spoorendonk (2024), Pihl (2023), and Larson et al. (2022 IJSPT). ICC 0.84–0.96 prone. Lower measurement error than seated testing.

Test C — Knee flexion · prone, hip 0°, knee 30° · proximal-specific

Patient

Position

Fully prone · hip at 0° · knee flexed to 30° (use a folded towel or small wedge under the distal thigh to maintain angle) · gripping table edge

Instruction

On command, pull your heel toward your buttocks as hard as possible — same as Test B but the starting position is much closer to straight. Keep your thigh flat on the table.

Clinician

Dynamometer placement

Pad on posterior lower leg, approximately 5 cm proximal to the lateral malleolus · ensure pad is perpendicular to the shank · resistance direction: downward toward the table

Stabilisation

Lean body weight into the dynamometer — resistance is substantially higher at 30° than at 90°. Elbows locked. Free hand stabilises posterior thigh.

This shortened-range position specifically loads the proximal tendon origin at the ischial tuberosity. Spoorendonk (2024) and Pihl (2023) both found this position remains more impaired longer than 90° following proximal avulsion — making it the most sensitive test for tracking recovery. Apply a 5% lower LSI threshold at each phase relative to Test B.

Converting raw force to N·m/kg

Step 1Measure lever arm: distance in metres from the lateral knee joint line to the dynamometer contact point on the leg

Step 2Torque (N·m) = Force (N) × Lever arm (m)

Step 3Normalise: N·m/kg = Torque ÷ Body mass (kg)

NoteMost HHD devices (Microfet2, Commander) output Newtons directly. Keep lever arm length consistent across sessions — measure and record it each time.

Score 0–100 · Higher score = better function

MIC Minimal Important Change (7 points) — the smallest score improvement that a patient would notice and consider meaningful. If a score changes by less than 7 points between two assessments, the difference is likely within measurement noise rather than real clinical change.

MDC Minimal Detectable Change (16 points) — the minimum change required to be statistically confident (95%) that a real change has occurred and is not just test-retest variability. Changes below 16 points may reflect true change or measurement error — interpret cautiously.

When Administer at baseline, then regularly as agreed upon — minimum every 6 weeks. Consistency of timing matters for meaningful comparison.

Section A — Pain (3 VAS items)

Pain at the ischial tuberosity at rest or during relaxed sitting

Rate your current pain level while sitting quietly or at rest

0 — no pain10 — worst imaginable

Pain when walking with long strides or uphill

Think of brisk walking or full-length steps on an incline

0 — no pain10 — worst imaginable

Pain with hamstring stretch — hip flexed, knee extended

The position that maximally loads the proximal hamstring origin

0 — no pain10 — worst imaginable

Section B — Function (4 items)

How long can you sit continuously without significant pain?

How long can you drive continuously without significant pain?

What is your current running capacity?

Soreness or tenderness at the ischial tuberosity

Rate tenderness with direct pressure or palpation

Adapted from Blakeney et al. (2017, Knee Surg Sports Traumatol Arthrosc). Items and domains reconstructed from published validation data. Original questionnaire available in the paper appendix (Springer/ESSKA paywall). MIC 7 pts, MDC 16 pts (Blakeney 2017).