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NCT Number: NCT07297511

Application of Multiple Vertical Jump Tests in Return-to-Play Assessment for Anterior Cruciate Ligament Reconstruction Athletes

Anterior cruciate ligament (ACL) injury is a common sports-related injury, particularly in sports that require extensive jumping and cutting movements. Although anterior cruciate ligament reconstruction (ACLR) surgery can restore knee stability, many athletes still face the risk of re-injury after returning to competition.Current return-to-play assessment relies primarily on single-plane horizontal hop tests and symmetry indices (LSI ≥ 90%); however, an increasing body of research suggests that these tests may not comprehensively reflect functional deficits in the vertical plane, repeated hopping, or high-intensity sport-specific activities.This study hypothesizes that incorporating multiple vertical jump tests-including single-leg vertical jumps and 10-second repeated vertical jumps-combined with advanced force plate analytics (such as Reactive Strength Index [RSI] and Time to Stabilization [TTS])-can more sensitively reveal residual neuromuscular control deficits following surgery. This approach would provide evidence-based guidance for return-to-play decision-making, thereby improving athletes' long-term athletic performance and safety.

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Key information

Conditions

ACL Reconstruction

Age range

18 year–35 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Kaohsiung Medical University

Kaohsiung City, Taiwan

About this study

This cross-sectional study compares biomechanical performance between ACLR athletes (>6 months post-op) and healthy controls to evaluate whether vertical jump protocols reveal greater limb asymmetries compared to traditional horizontal hop tests. Following a 5-minute stationary bicycle warm-up and familiarization trials, participants perform four unilateral tasks on both limbs: Single-Legged Hop for Distance (SHD), Crossover Hop for Distance (CHD), Single-Legged Vertical Countermovement Jump (SLVJ), and 10-Second Repeated Single-Legged Vertical Jump (SLVJs). All tasks are performed with hands on hips to minimize compensatory motion. Three successful trials are recorded per limb per task with 3-minute rest intervals between sets. Trials are discarded if participants land on the contralateral limb, lose balance, or fail to land on the force plate. Vertical ground reaction forces are collected using a dual-force plate system (Hawkin Dynamics, 3rd Generation) at 1000 Hz. Data processing calculates Limb Symmetry Index (LSI), Modified Reactive Strength Index (RSI) from SLVJs as Jump Height divided by Movement Time, Time to Stabilization (TTS) defined as the duration for vGRF to stabilize within ±5% of body weight, and eccentric/concentric impulse.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 1.Age 18-35 years

2.Unilateral anterior cruciate ligament (ACL) rupture confirmed by magnetic resonance imaging (MRI)

3.Positive Lachman test grade ≥2 pre-operatively

4.Anterior cruciate ligament reconstruction (ACLR) using hamstring or gracilis autograft

5.Post-operative time ≥6 months

6.Completed rehabilitation program with clearance from orthopedic surgeon or physical therapist

7.Quadriceps strength symmetry index ≥90%

.Elite athlete status (prior participation in national-level competitions)

Exclusion criteria

  • Other lower extremity injuries or pathologies (including other knee ligament injuries)
  • Contralateral lower limb injury within the past 3 months
  • Quadriceps strength symmetry index <90%
  • Non-elite athlete status (no prior national-level competition participation)
  • Incomplete rehabilitation or lack of medical clearance

Treatment and study plan

Primary outcomes

  1. Limb asymmetry index,LSI

    Time frame: At baseline (single testing session; no longitudinal follow-up)

    Limb Symmetry Index (LSI) calculated as (|Uninvolved limb value - Involved limb value| / (Uninvolved limb value + Involved limb value)) × 100% for each of the four jump tasks: Single-Legged Hop for Distance (SHD), Crossover Hop for Distance (CHD), Single-Legged Vertical Countermovement Jump (SLVJ), and 10-Second Repeated Single-Legged Vertical Jump (SLVJs). LSI values will be compared between ACLR athletes and healthy controls to determine whether vertical jump protocols reveal greater limb asymmetries than traditional horizontal hop tests. Primary analysis will examine whether LSI differences in vertical jump tasks are statistically significantly lower (indicating greater asymmetry) than horizontal hop tasks, revealing residual neuromuscular deficits not detected by conventional return-to-play assessment.

Secondary outcomes

  1. Modified Reactive Strength Index

    Time frame: At baseline (single testing session; no longitudinal follow-up)

    Modified Reactive Strength Index (mRSI) calculated as Flight Time(s) divided by Time to Take-off(s) for the 10-Second Repeated Single-Legged Vertical Jump (SLVJs) task.

  2. Time to Stabilization (seconds)

    Time frame: At baseline (single testing session; no longitudinal follow-up)

    Time to Stabilization (TTS) measured during the Single-Legged Vertical Countermovement Jump (SLVJ) task, defined as the time required for vertical ground reaction force (vGRF) to return to and stabilize within ±5% of the participant's body weight following landing.

  3. Single-Legged Hop for Distance (centimeter)

    Time frame: At baseline (single testing session; no longitudinal follow-up)

    Single-Legged Hop for Distance (SHD) measured as the maximum horizontal distance(centimeter) achieved during a single maximal hop on the tested leg, performed bilaterally.

  4. Crossover Hop for Distance (centimeter)

    Time frame: At baseline (single testing session; no longitudinal follow-up)

    Crossover Hop for Distance (CHD) measured as the total horizontal distance covered during three consecutive hops crossing a centerline, performed bilaterally with emphasis on stability and continuity.

  5. Jump Height(meter)

    Time frame: At baseline (single testing session; no longitudinal follow-up)

    Jump Height measured during the Single-Legged Vertical Countermovement Jump (SLVJ) and 10-Second Repeated Single-Legged Vertical Jump (SLVJs) tasks, calculated from the flight time (time from takeoff to landing) using force plate data.

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Sponsors and collaborators

Lead sponsor

Kaohsiung Medical University

Other

Registry information

Official study title

The Application of Vertical Jump Performance in Return-to-Play Assessment for Anterior Cruciate Ligament Reconstruction Athletes

Acronym: RTP-VJ

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Dec 22, 2025
Registry last updated
Dec 22, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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