RTC Test Battery – Longitudinal Comparison and Clinical Interpretation

Table of Contents

  1. Overview
  2. Hop Tests and Functional Symmetry
  3. Y-Balance Test (YBT) – Dynamic Balance
  4. Star Excursion Balance Test (SEBT)
  5. CAIT – Cumberland Ankle Instability Tool
  6. I-PRRS – Psychological Readiness to Return to Sport
  7. MIS – Manchester Instability Score
  8. Normalized Balance Reach Distances
  9. Clinical Traffic Light Classification
  10. Evidence-Based Interpretation
  11. References
  12. One-Minute-Paper Topics

Overview

This lecture presents a longitudinal case study of athlete xyz18 (KS224), a 22-year-old male soccer player who sustained a right ankle injury on 31.08.2024. Two Return to Competition (RTC) test battery assessments were performed at different rehabilitation stages and are compared systematically to illustrate clinical interpretation, threshold-based classification, and evidence-based decision-making for return-to-sport clearance.

ParameterTest 1Test 2
Date15.11.202413.02.2025
Days post-injury76166
Rehabilitation stageEarlyLate

The RTC test battery comprises functional hop tests, dynamic balance assessments, self-reported questionnaires for ankle instability, psychological readiness, and pain, providing a multidimensional assessment framework for return-to-sport decisions.

1 Hop Tests and Functional Symmetry

The Limb Symmetry Index (LSI) is calculated as the ratio of the weaker to the stronger side (multiplied by 100%). LSI thresholds classify injury risk as follows: 90–110% is considered normal (green), 85–89% or 111–115% indicates slightly increased risk (yellow), and values below 85% or above 115% indicate significantly increased risk (red).

  • Test 1 findings: All five hop tests (Single, Triple, Triple-X, Square, Side) showed marked asymmetries with LSI values ranging from 76.4% to 81.8%, well below the 90% clinical threshold. The injured right side demonstrated significantly reduced jump distances across all tests, consistent with the expected profile at 76 days post-injury.

  • Test 2 findings: All LSI values improved to the range of 92.4–100.0%, placing them within the green normal range. Symmetry improved by 14–24 percentage points. This meets the minimum criterion for return-to-sport clearance as described by Grindem et al. 2016 and van Melick et al. 2016.

  • Double-Hop tests: Bilateral jump performance (single and triple hop) also showed marked improvement from Test 1 to Test 2 in absolute jump distances, reflecting improved bilateral power generation.

2 Y-Balance Test (YBT) – Dynamic Balance

The Y-Balance Test assesses dynamic single-limb balance in three reach directions: Anterior, Posteromedial, and Posterolateral. Clinical thresholds for side-to-side difference are: less than 2 cm indicates good balance (green), 2–4 cm indicates noticeable imbalance (yellow), and greater than 4 cm indicates increased injury risk (red). Plisky et al. (2006) demonstrated that anterior side differences greater than 4 cm are associated with a 2.5-fold increased injury risk.

  • Test 1 findings: Massive side-to-side differences in all three directions (8–14 cm), all well above the 4 cm threshold. The injured right side showed substantially reduced reach distances, indicating significant proprioceptive and neuromuscular deficits.

  • Test 2 findings: Side-to-side differences reduced to 0.0–1.7 cm, all within the green range. The proprioceptive and neuromuscular control of the injured side has largely normalized.

3 Star Excursion Balance Test (SEBT)

The SEBT extends the balance assessment to four directions: Anterior, Medial Dexter, Medial Sinister, and Posterior. The same clinical thresholds apply as for the YBT (2 cm and 4 cm side-to-side difference cutoffs).

  • Test 1 findings: Extreme side-to-side differences (13–18 cm), particularly in the posterior and medial directions, indicating severe balance and neuromuscular control deficits on the injured side.

  • Test 2 findings: Differences reduced to 0.3–1.7 cm. The balance profile is now largely symmetric, demonstrating effective rehabilitation of neuromuscular control.

4 CAIT – Cumberland Ankle Instability Tool

The CAIT is a self-reported questionnaire (maximum 30 points) that quantifies perceived ankle instability. Scores of 24 or below indicate chronic ankle instability (red), scores of 25–27 indicate increased likelihood of instability (yellow), and scores above 27 are unremarkable (green). Hiller et al. (2006) established the CAIT with an ICC of 0.96. Wright et al. (2014) recalibrated the cutoff to 25 or below.

  • Test 1 findings: CAIT right (injured) scored 13 points, indicating severe chronic instability. CAIT left scored 22 points, also below the instability threshold.

  • Test 2 findings: CAIT right improved to 27 points (improvement of 14 points). CAIT left remained at 22 points.

  • Recommendation: Continue targeted proprioceptive and sensorimotor training for ankle stability. The injured side has improved substantially but should be monitored.

5 I-PRRS – Psychological Readiness to Return to Sport

The Injury-Psychological Readiness to Return to Sport (I-PRRS) scale measures psychological readiness across 6 items, each scored 0–100: Confidence in Performance, Confidence in Competition, Relaxation in Competition, No Fear of Reinjury, Confidence in Sport Skill, and Confidence Giving 100%. A mean score below 50 indicates the athlete is psychologically not yet ready to return to sport. According to Glazer (2009), a score above 60 indicates maximum confidence.

  • Test 1 findings: I-PRRS mean of 35.0, well below the threshold of 50. The athlete was psychologically not ready to return to sport. Particularly low scores on No Fear of Reinjury (25) and Relaxation in Competition (30) reflect significant psychological barriers.

  • Test 2 findings: I-PRRS mean improved dramatically to 95.8, confirming psychological readiness. All items scored 75 or above. The improvement of 60.8 points represents one of the largest changes across the entire test battery.

6 MIS – Manchester Instability Score

The MIS captures pain symptoms across 5 subscales: Pressure, Stretch Pain, Neutral Position, End Feel, and Knee Extension. Higher scores indicate more pain and instability. A total score of 3 or below is considered normal, 4–8 warrants observation, and above 8 is abnormal.

  • Test 1 findings: MIS total of 25 points, indicating significant pain symptoms. Highest subscale scores were Stretch Pain (7), Pressure (6), and End Feel (5).

  • Test 2 findings: MIS total reduced to 0, the athlete is completely pain-free. This reduction of 25 points is a strong positive indicator for the return-to-sport decision.

7 Normalized Balance Reach Distances

YBT and SEBT reach distances are normalized to leg length (measured as left 86.5 cm, right 86.3 cm) and expressed as a percentage. This normalization allows comparison across athletes of different body dimensions and is recommended in the literature. A reference value of 94% leg length has been proposed as a benchmark for adequate dynamic balance.

  • Test 1: Normalized values showed substantial asymmetry with the injured right side consistently below both the uninjured side and the 94% reference across all reach directions.

  • Test 2: Normalized values are largely symmetric and near or above the 94% reference for most directions, indicating adequate functional balance capacity.

8 Clinical Traffic Light Classification

Each test domain is classified using a traffic light system (green, yellow, red) based on established clinical thresholds. This provides a rapid visual summary of the athlete’s readiness across all domains.

AssessmentTest 1Test 2
Green (normal)0 / 16 domains14 / 16 domains
Yellow (observation)0 / 16 domains1 / 16 domains
Red (abnormal)16 / 16 domains1 / 16 domains

The improvement from 0 green domains at Test 1 to 14 green domains at Test 2 illustrates the substantial rehabilitation progress over the 90-day interval between assessments. The remaining non-green domains relate to CAIT ankle instability, which requires continued attention.

9 Evidence-Based Interpretation

Test 1 – Early Rehabilitation Phase (76 days post-injury)

The initial assessment presents the expected pattern of an early rehabilitation phase after right ankle injury: significant hop test asymmetries (LSI 76–82%), massive balance deficits (side-to-side differences of 8–18 cm), severe perceived ankle instability (CAIT 13), low psychological readiness (I-PRRS 35.0), and substantial pain symptoms (MIS 25). All 16 domains are classified as red.

Test 2 – Late Rehabilitation Phase (166 days post-injury)

The follow-up assessment demonstrates marked improvement across nearly all domains: hop test symmetry restored to 92–100% (all green), balance differences reduced to 0–2 cm (predominantly green), dramatic improvement in psychological readiness (I-PRRS 95.8), and complete pain resolution (MIS 0). Only CAIT on the injured side remains a concern.

Overall Assessment and Recommendations

DomainTest 1Test 2Assessment
Hop-Test SymmetryLSI 76–82%All LSI > 90%Criterion met
YBT Side Difference8–14 cmAll < 2 cmCriterion met
SEBT Side Difference13–18 cm0.3–1.7 cmCriterion met
CAIT (right)13 pts27 ptsImproved, continue monitoring
I-PRRS35.095.8Readiness confirmed
MIS250Pain-free
  • Good functional symmetry and psychological readiness support a gradual increase in training load.
  • CAIT scores on the injured side warrant continued proprioceptive training.
  • The return-to-sport decision should follow the Shared Decision-Making principle as recommended by Ardern et al. 2016.

References

[1] Ardern CL, Glasgow P, Schneiders A, et al. 2016 Consensus statement on return to sport from the First World Congress in Sports Physical Therapy, Bern. Br J Sports Med. 2016;50(14):853-864.

[2] Glazer DD. Development and preliminary validation of the Injury-Psychological Readiness to Return to Sport (I-PRRS) Scale. J Athl Train. 2009;44(2):185-189.

[3] Gribble PA, Delahunt E, Bleakley CM, et al. Selection criteria for patients with chronic ankle instability in controlled research: a position statement of the International Ankle Consortium. Br J Sports Med. 2014;48(13):1014-1018.

[4] Grindem H, Snyder-Mackler L, et al. Simple decision rules can reduce reinjury risk by 84% after ACL reconstruction: the Delaware-Oslo ACL cohort study. Br J Sports Med. 2016;50(13):804-808.

[5] Hiller CE, Refshauge KM, Bundy AC, Herbert RD, Kilbreath SL. The Cumberland Ankle Instability Tool: a report of validity and reliability testing. Arch Phys Med Rehabil. 2006;87(9):1235-1241.

[6] Plisky PJ, Rauh MJ, Kaminski TW, Underwood FB. Star Excursion Balance Test as a predictor of lower extremity injury in high school basketball players. J Orthop Sports Phys Ther. 2006;36(12):911-919.

[7] van Melick N, van Cingel REH, Brooijmans F, et al. Evidence-based clinical practice update: practice guidelines for anterior cruciate ligament rehabilitation based on a systematic review and multidisciplinary consensus. Br J Sports Med. 2016;50(24):1506-1515.

[8] Wright CJ, Arnold BL, Ross SE, Linens SW. Recalibration and validation of the Cumberland Ankle Instability Tool cutoff score for individuals with chronic ankle instability. Arch Phys Med Rehabil. 2014;95(10):1853-1859.

One-Minute-Paper Topics

A One-Minute-Paper (OMP) is a short, focused prompt that students answer in ~60 seconds at the end of a session to consolidate learning, surface misconceptions, and provide formative feedback. When answering, be concise, specific, and use terminology from today’s session.

  1. Define the Limb Symmetry Index (LSI), state its formula, and explain the three traffic-light classification zones used in the RTC battery.
  2. In the case study (athlete KS224), LSI values for all hop tests were 76–82% at Test 1 and 92–100% at Test 2. What does this progression indicate clinically?
  3. Explain the clinical threshold for the Y-Balance Test anterior reach direction (Plisky et al. 2006) and state the associated injury risk increase.
  4. Describe the three reach directions of the Y-Balance Test and explain what a side-to-side difference of >4 cm means for return-to-competition clearance.
  5. What is the Star Excursion Balance Test (SEBT) and how does it extend the information provided by the YBT?
  6. Define the Cumberland Ankle Instability Tool (CAIT): what does it measure, what is the maximum score, and what cut-off indicates functional ankle instability?
  7. Explain what the I-PRRS (Injury-Psychological Readiness to Return to Sport) scale measures and how it complements physical performance tests.
  8. What is the Manchester Instability Score (MIS) and in which clinical context is it used?
  9. How are normalized reach distances calculated in the SEBT/YBT, and why is normalization to limb length necessary for valid comparison?
  10. Describe the overall pattern of change from Test 1 (76 days post-injury) to Test 2 (166 days post-injury) across all RTC battery domains in the case study.
  11. At which test point would you recommend return-to-competition clearance for athlete KS224, and which specific test results support this decision?
  12. What is the clinical significance of a “yellow zone” classification on a single RTC measure when all other measures are green?
  13. Explain how the multi-domain structure of the RTC battery (functional, balance, psychological, self-report) guards against premature clearance based on a single strong result.
  14. Describe one instance in the case study where a functional test result and a self-reported questionnaire result appeared discordant, and how you would interpret this clinically.
  15. Why is longitudinal comparison (two or more time points) more informative than a single cross-sectional assessment in return-to-sport decisions?
  16. How should the clinician communicate traffic-light results to the athlete and coaching team without creating undue alarm or false reassurance?
  17. What are the limitations of the LSI framework when the contralateral (reference) limb is also sub-optimal after bilateral injury or deconditioning?
  18. Explain the role of double-hop tests (bilateral jump performance) in the RTC battery alongside the standard LSI-based single-limb tests.
  19. Which finding from the longitudinal comparison in today’s case study surprised you most, and what does it imply for rehabilitation pacing?
  20. Formulate one question about the clinical interpretation of RTC test batteries that you would like to explore in the next session.