Functional Resistance Training to Improve Knee Function After ACL Reconstruction

Not Applicable

Completed

• Conditions: Anterior Cruciate Ligament Injury
• Interventions: Other: Control; Other: Functional Resistance Training with Brace; Other: Functional Resistance Training with Elastic Band

• Registration Number: NCT03282565
• Lead Sponsor: University of Michigan

Brief Summary

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.

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 Timeline

• Study First Submitted: 2017-09-12
• Study First Submitted QC: 2017-09-12
• Study First Posted: 2017-09-14
• Study Start: 2018-03-17
• Primary Completion: 2020-12-01
• Study Completion: 2020-12-01
• Results First Submitted: 2021-11-04
• Status Verified: 2022-01
• Results First Submitted QC: 2022-01-13
• Last Update Submitted: 2022-01-13
• Results First Posted: 2022-01-18
• Last Update Posted: 2022-01-18

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 30

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

Read More

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.).

Read More

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Control	Control	Participants will while on a treadmill without an applied resistance 2-3 times a week for about 8 weeks.
Functional Resistance Training with a Brace	Functional Resistance Training with 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.
Functional Resistance Training with Elastic Band	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.

Primary Outcome Measures

Name	Time	Method
Quadriceps Muscle Strength	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.	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.

Secondary Outcome Measures

Name	Time	Method
Knee Flexion Angle Symmetry	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)	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.
Knee Moment Symmetry	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	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.
Quadriceps Voluntary Activation	Immediately after the intervention or approximately 18-20 weeks after ACL reconstruction	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.

Trial Locations

Locations (1)

University of Michigan; 🇺🇸 Ann Arbor, Michigan, United States