Functional Resistance Training to Improve Knee Function After ACL Reconstruction

Functional Resistance Training During Gait: A Novel Intervention to Improve Knee Knee Function After ACL Reconstruction

The purpose of this study is to examine if thigh muscle weakness and the lack of muscle activation that accompanies ACL injury and reconstruction can be improved with functional resistance training.

Study Overview

• Status: Completed
• Conditions: Anterior Cruciate Ligament Injury
• Intervention / Treatment: Other: Functional Resistance Training with Brace; Other: Functional Resistance Training with Elastic Band; Other: Control

Detailed Description

Profound quadriceps weakness is ubiquitous after anterior cruciate ligament (ACL) reconstruction, and current rehabilitation approaches are not successful in optimizing quadriceps strength and knee function even years after the surgery. We hypothesize that suboptimal strength and functional outcomes after ACL surgery are due to the lack of task-specific exercise elements during strength training. This application seeks to assess whether progressive functional resistance training during gait will significantly improve quadriceps function, neural excitability, and knee mechanics during gait. The proposed studies will not only lay the foundation for a novel training paradigm, but will also improve our understanding of the mechanisms mediating neuromuscular and biomechanical changes after functional resistance training.

• Study Type: Interventional
• Enrollment (Actual): 30
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Michigan
    • Ann Arbor, Michigan, United States, 48109
      • University of Michigan

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 14 years to 40 years (Child, Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• aged 14-40 years
• suffered an acute, complete ACL rupture
• 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
• previous ACL injury
• previous surgery to either knee
• bony fracture accompanying ACL injury
• patients who experienced a knee dislocation;
• patients who are contraindicated for transcranial magnetic stimulation (e.g., metal implants in head, unexplained recurrent headaches, history of seizures, epileptogenic drugs, active psychiatric illness, etc.).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Functional Resistance Training with a Brace; Participants will receive functional resistance training via a knee brace while walking on a treadmill 2-3 times a week for about 8 weeks.	Other: Functional Resistance Training with Brace; A brace will be strapped to the leg and apply resistance across the knee while subjects walk on a treadmill.
Experimental: Functional Resistance Training with Elastic Band; Participants will receive functional resistance training via an elastic band attached at the ankle while walking on a treadmill 2-3 times a week for about 8 weeks.	Other: Functional Resistance Training with Elastic Band; An elastic band will be strapped to the leg and apply resistance across the knee while subjects walk on a treadmill.
Sham Comparator: Control; Participants will while on a treadmill without an applied resistance 2-3 times a week for about 8 weeks.	Other: Control; A brace will be strapped to the leg and will not apply resistance across the knee while subjects walk on a treadmill.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Quadriceps Muscle Strength	Isometric quadriceps strength was measured with the knee at 60 degrees using an isokinetic dynamometer prior to the intervention and immediately after the intervention. Post-test minus pre-test change scores were calculated.	Pre-test measurements were taken at ~9-10 weeks after ACL reconstruction and Post-test measurements were taken at ~18-20 weeks after ACL reconstruction.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Quadriceps Voluntary Activation	Quadriceps voluntary activation was measured using the burst superimposition technique and calculated using the central activation ratio (CAR). The CAR formula is calculated using the peak torque generated immediately prior to the delivery of the stimulus (or the maximum voluntary isometric contraction, MVIC) being divided by the peak torque generated as a result of the electrical stimulus (MVIC plus superimposed burst) and then multiplied by 100. Equation is: MVIC/(MVIC + superimposed burst) × 100. A CAR of 100 represents complete volitional quadriceps activation. Voluntary activation was quantified immediately after the intervenapproximately 9-10 weeks after the int from baseline to the end of intervention will be assessed and compared between groups.	Immediately after the intervention or approximately 18-20 weeks after ACL reconstruction
Knee Flexion Angle Symmetry	The knee flexion angle (measured in degrees) during the stance phase was gathered for both limbs using three dimension motion capture and recorded while subjects walked overground. A knee flexion angle symmetry score was computed using the following formula: ensemble average of knee flexion angle of ACL limb minus the ensemble average of knee flexion angle of the non-ACL limb. The mean difference between pre-intervention and post-intervention (post minus pre) knee flexion symmetry scores were calculated for each group. Higher values suggest greater increases in knee flexion angle symmetry from pre-intervention to post-intervention.	Pre-intervention values were recorded at ~9-10 weeks after ACL reconstruction and before the start of the intervention. Post-intervention values were recorded after the 8-week intervention (~18-20 weeks after ACL reconstruction)
Knee Moment Symmetry	The sagittal plane knee moment (units Nm) during the stance phase was gathered for both limbs using three dimensional motion capture and recorded while subjects walk overground. A symmetry score was computed using the following formula: ensemble average of the knee moment of the ACL limb (Nm) - ensemble average of the knee moment of the non-ACL limb (Nm). The mean difference between pre-intervention and post-intervention knee moment symmetry scores (post minus pre) were calculated for each group. Higher values represent the greater increases in knee moment symmetry from pre-intervention to post-intervention.	Pre-intervention scores were recorded prior to the start of the intervention and approximately 9-10 weeks after ACL reconstruction. Post-intervention scores were recorded after the 8 week intervention or approximately 18-20 weeks after ACL reconstruction

Collaborators and Investigators

• Sponsor: University of Michigan
• Collaborators: Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD); National Institutes of Health (NIH)
• Investigators: Principal Investigator: Riann Palmieri-Smith, PhD, University of Michigan; Principal Investigator: Chandramouli Krishnan, PhD, University of Michigan

Study record dates

Study Major Dates

• Study Start (Actual): March 17, 2018
• Primary Completion (Actual): December 1, 2020
• Study Completion (Actual): December 1, 2020

Study Registration Dates

• First Submitted: September 12, 2017
• First Submitted That Met QC Criteria: September 12, 2017
• First Posted (Actual): September 14, 2017

Study Record Updates

• Last Update Posted (Actual): January 18, 2022
• Last Update Submitted That Met QC Criteria: January 13, 2022
• Last Verified: January 1, 2022

More Information

Terms related to this study

• Keywords: ACL; Resistance Training; Muscle; Quadriceps
• Additional Relevant MeSH Terms: Wounds and Injuries; Leg Injuries; Knee Injuries; Anterior Cruciate Ligament Injuries
• Other Study ID Numbers: HUM00133860; R21HD092614 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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