Michigan Split-belt Treadmill Training Program to Improve Long-Term Knee Biomechanics After ACL Reconstruction

NCT ID: NCT06529692

Last Updated: 2025-09-08

Basic Information

• Recruitment Status: RECRUITING
• Clinical Phase: NA
• Total Enrollment: 9 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2025-08-13
• Study Completion Date: 2026-08-31

Brief Summary

The goal of this study is to gather pilot data to help inform a future clinical trial. As such, the investigators will employ a randomized clinical trial design, but data will only be collected on 9 total subjects. Nine subjects will be randomized to 2 split-belt intervention groups (one group where early stance loading is trained and the other where midstance loading is trained) and a placebo group.

The goal of this study is to explore the adaptations in knee loading from a 6-week split-belt training intervention.

The investigators' main question for this aim is:

1. Does knee loading, measured by the sagittal plane knee moment, change to a greater extent in the split-belt treadmill training groups compared to the placebo group?

2. Are there differences in training-related knee loading changes between individuals trained in the early stance vs. midstance loading split-belt training?

Detailed Description

It is commonplace for individuals after anterior cruciate ligament (ACL) reconstruction to shift mechanical demands away from their surgical knee and limb. This manifests as diminished knee moments and vertical ground reaction forces in the ACL limb during everyday tasks (e.g., walking, running, standing, landing, etc.) and persists for as long as 2.5 years after surgery. This pattern of underloading is considered maladaptive, as it has been linked to re-injury and biological markers that are consistent with the development of post-traumatic osteoarthritis that affects over 50% of knees 10-20 years after surgical reconstruction.

Split-belt treadmill training is a gait retraining approach where treadmill belt speeds are decoupled (i.e., one belt is set to move at a faster or slower speed than the other belt) during walking. Split-belt training is based on well-established motor learning principles, such as error-based learning and variability of practice which can lead to locomotor adaptations. In healthy individuals, split-belt treadmill walking significantly increases (from baseline) knee moment impulses in the limb on the slow belt than on the fast belt during the braking and propulsive phases of gait. Split-belt treadmill training has also shown promise in individuals with neurological deficits, resulting in significant improvements in gait biomechanics after training.

To explore the adaptations in loading from a 6-week split-belt training intervention, the investigators will conduct a pilot randomized clinical trial design, but data will only be collected on 9 total subjects. Nine subjects will be randomized to one of 3 groups: 1) early stance split-belt treadmill training, 2) mid-stance split-belt treadmill training, or 3) placebo split-belt treadmill training. The primary outcome, sagittal plane knee moment, will be examined before, midway, & after the 6-weeks of training. Other outcomes, vertical ground reaction force, knee joint contact force, and the Knee Injury and Osteoarthritis Outcome Score, will be measured at the same timepoints. Medial and lateral knee cartilage thickness are additional outcomes that will only be assessed before and after training.

Conditions

ACL; Anterior Cruciate Ligament; ACL Injury

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: SINGLE

Study Groups

Early Stance Training

This study arm will complete 6-weeks of a split-belt treadmill training program. The program will require participants to walk on a split-belt treadmill 2 times a week for 20 minutes with the ACL leg walking at 150-170% of 1.1 m/s and the Non-ACL leg walking at 1.1 m/s.

Group Type: EXPERIMENTAL

Split-Belt Training

Intervention Type: BEHAVIORAL

Walking on a split-belt treadmill in which the treadmill belt under the ACL leg will move at a speed faster or slower than the belt under the Non-ACL leg.

Mid-Stance Training

This study arm will complete 6-weeks of a split-belt treadmill training program. The program will require participants to walk on a split-belt treadmill 2 times a week for 20 minutes with the ACL leg walking at 30-50% of 1.1 m/s and the Non-ACL leg walking at 1.1 m/s.

Group Type: EXPERIMENTAL

Split-Belt Training

Intervention Type: BEHAVIORAL

Walking on a split-belt treadmill in which the treadmill belt under the ACL leg will move at a speed faster or slower than the belt under the Non-ACL leg.

Placebo Split-Belt Training

This study arm will complete 6-weeks of a split-belt treadmill training program. The program will require participants to walk on a split-belt treadmill 2 times a week for 20 minutes with the ACL leg walking at a speed that is 10% different from 1.1 m/s and the Non-ACL leg walking at 1.1 m/s.

Group Type: PLACEBO_COMPARATOR

Placebo Split-Belt Training

Intervention Type: BEHAVIORAL

Walking on a split-belt treadmill in which the belt under the ACL leg will move at a speed that is minimally slower than the other belt.

Interventions

Placebo Split-Belt Training

Walking on a split-belt treadmill in which the belt under the ACL leg will move at a speed that is minimally slower than the other belt.

Intervention Type: BEHAVIORAL

Split-Belt Training

Walking on a split-belt treadmill in which the treadmill belt under the ACL leg will move at a speed faster or slower than the belt under the Non-ACL leg.

Intervention Type: BEHAVIORAL

Eligibility Criteria

Inclusion Criteria

• aged 14-45 years
• suffered an acute, complete ACL rupture as confirmed by MRI and physical exam
• have undergone ACL reconstruction w autograft within the past 10 months
• willingness to participate in testing and follow-up as outlined in the protocol
• English-speaking

Exclusion Criteria

• inability to provide written informed consent
• female subjects who are pregnant or are planning to become pregnant (self-reported)
• previous ACL injury
• previous surgery to either knee
• bony fracture accompanying ACL injury
• patients who experienced a knee dislocation
• patients who had their ACL reconstructed with an allograft
• patients who underwent a multi-ligamentous and/or staged ACL reconstruction

• Minimum Eligible Age: 14 Years
• Maximum Eligible Age: 45 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)

NIH

Sponsor Role: collaborator

University of Michigan

OTHER

Sponsor Role: lead

Responsible Party

Riann Palmieri-Smith

Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Riann M Palmieri-Smith, PhD, ATC

Role: PRINCIPAL_INVESTIGATOR

University of Michigan

Chandramouli Krishnan, PT, PhD

Role: PRINCIPAL_INVESTIGATOR

University of Michigan

Locations

University of Michigan

Ann Arbor, Michigan, United States

Site Status: RECRUITING

Countries

United States

Central Contacts

Alexa Johnson, PhD

Role: CONTACT

akjohns@umich.edu

734-615-1297

Riann M Palmieri-Smith, PhD, ATC

Role: CONTACT

riannp@umich.edu

734-615-3154

Facility Contacts

Riann Palmieri-Smith, PhD

Role: primary

riannp@umich.edu

7348343342

Alexa Johnson, PhD

Role: backup

akjohns@med.umich.edu

734-615-1297

Other Identifiers

1R21AR082643

Identifier Type: NIH

Identifier Source: secondary_id

View Link

HUM00221406_Aim3

Identifier Type: -

Identifier Source: org_study_id