Trunk and Lower Limb Muscle Contributions to ACL Loading During Single-Leg Landing

Anterior cruciate ligament (ACL) injuries commonly occurred through non-contact mechanisms during dynamic tasks such as single-leg landing (SLL). Trunk control and lower limb muscle coordination were believed to play a critical role in modulating knee joint biomechanics and ACL loading; however, their individual muscle contributions remained poorly understood due to the difficulty of in-vivo ACL force measurement. This cross-sectional study aimed to investigate the relationship between core strength, lower limb muscle forces, knee joint biomechanics, and ACL loading during single-leg landing in collegiate athletes. Three-dimensional full-body kinematics, ground reaction forces, and electromyography data were collected and integrated into a musculoskeletal modelling framework to estimate ACL loading and individual muscle force contributions. Findings from this study were expected to provide biomechanical evidence to support targeted injury-prevention and rehabilitation strategies.

Study Overview

• Status: Completed
• Conditions: ACL

Detailed Description

Anterior cruciate ligament injuries often led to long-term consequences including early knee osteoarthritis, abnormal neuromuscular function, and reduced athletic participation. Approximately 70% of ACL injuries occurred via non-contact mechanisms, frequently during single-leg landing tasks. During such movements, ACL loading was influenced by joint kinematics, external forces, and neuromuscular coordination of both trunk and lower limb muscles. This study adopted a two-level approach. First, standard biomechanical analyses were conducted to evaluate the relationship between functional core strength and knee joint biomechanics, including knee valgus angle and knee abduction moment during SLL. Second, a musculoskeletal modelling approach was employed to quantify the contribution of individual trunk and lower limb muscles to ACL loading.

Participants performed standardized single-leg landing tasks while wearing inertial motion sensors and surface electromyography electrodes. Ground reaction forces were recorded using a force platform. A full-body musculoskeletal model was scaled to participant anthropometry and used to estimate muscle forces and ACL loading during the landing phase. Statistical analyses included linear regression and linear mixed-effects modelling to examine relationships between muscle forces, knee biomechanics, and ACL loading.

• Study Type: Observational
• Enrollment (Actual): 40

Contacts and Locations

Study Locations

• Malaysia
  • Pulau Pinang
    • Nibong Tebal, Pulau Pinang, Malaysia
      • School of Mechanical Engineering, Universiti Sains Malaysia

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

The study population consisted of forty collegiate male athletes aged 19 to 25 years who participated in sports involving frequent jumping and landing movements. All participants had a minimum of three years of competitive experience and trained at least twice per week. Individuals with a history of major lower limb or back injury requiring surgery, current musculoskeletal injury, or medical conditions limiting maximal physical effort were excluded. All participants provided written informed consent prior to participation.

Description

Inclusion Criteria:

• Male collegiate athletes aged 19-25 years
• Minimum of 3 years of competitive experience in jump-landing sports (e.g., volleyball, basketball, netball)
• Training frequency of at least twice per week
• No history of back or lower limb injury

Exclusion Criteria:

• History of major lower limb or back injury requiring surgery
• Any medical condition preventing maximal physical effort
• Current musculoskeletal pain or injury affecting movement performance

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Peak Anterior Cruciate Ligament (ACL) Force During Single-Leg Landing	Peak anterior cruciate ligament (ACL) force (Newtons, N) was estimated during the landing phase of a single-leg landing task using subject-specific musculoskeletal modelling. Three-dimensional whole-body kinematics (Xsens inertial motion capture), ground reaction forces (Bertec force platform), and surface electromyography (EMG) signals from trunk and lower limb muscles were integrated within a full-body musculoskeletal model to compute ACL loading. Peak ACL force was extracted from initial ground contact to maximum knee flexion.	Assessed during a single laboratory testing session (up to 2 hours).
Correlation Between Plank Endurance Time and Peak Knee Valgus Angle During Single-Leg Landing	Pearson correlation between plank endurance time (seconds) and peak knee valgus angle (degrees) measured during single-leg landing using three-dimensional motion analysis (Xsens inertial motion capture).	Assessed during a single laboratory testing session (up to 2 hours).
Knee Valgus Angle During Single-Leg Landing	Peak knee valgus angle (degrees, °) was calculated from three-dimensional lower limb kinematic data collected using full-body inertial motion capture (Xsens). Knee joint angles were derived using inverse kinematics and analyzed from initial ground contact to maximum knee flexion during the single-leg landing task.	Assessed during a single laboratory testing session (up to 2 hours).
Knee Abduction Moment During Single-Leg Landing	Peak knee abduction moment (Newton-meters, Nm) was computed using inverse dynamics based on synchronized three-dimensional kinematic data (Xsens) and ground reaction force data (Bertec force platform). Peak values were identified during the landing phase from initial ground contact to maximum knee flexion.	Assessed during a single laboratory testing session (up to 2 hours).
Trunk and Lower Limb Muscle Forces During Single-Leg Landing	Peak trunk and lower limb muscle forces (Newtons, N) were estimated using a full-body lumbar spine musculoskeletal model driven by experimental kinematics, ground reaction forces, and electromyography-informed muscle activation patterns. Muscle force outputs were analyzed during the landing phase of the single-leg landing task from initial ground contact to maximum knee flexion.	Assessed during a single laboratory testing session (up to 2 hours).

Collaborators and Investigators

• Sponsor: Universiti Sains Malaysia

Study record dates

Study Major Dates

• Study Start (Actual): June 12, 2024
• Primary Completion (Actual): July 11, 2024
• Study Completion (Actual): July 11, 2024

Study Registration Dates

• First Submitted: January 1, 2026
• First Submitted That Met QC Criteria: May 19, 2026
• First Posted (Actual): May 27, 2026

Study Record Updates

• Last Update Posted (Actual): May 27, 2026
• Last Update Submitted That Met QC Criteria: May 19, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: USM/JEPeM/KK/23100759

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No