Anterior Cruciate Ligament Injury
Conditions
Keywords
ACL, Quadriceps, Muscle, Resistance Training
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.
Interventions
OTHERFunctional Resistance Training with Brace
A brace will be strapped to the leg and apply resistance across the knee while subjects walk on a treadmill.
OTHERControl
A brace will be strapped to the leg and will not apply resistance across the knee while subjects walk on a treadmill.
OTHERFunctional 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.
Sponsors
National Institutes of Health (NIH)
Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
University of Michigan
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
14 Years to 40 Years
Healthy volunteers
No
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.).
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| 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
| Measure | Time frame | Description |
|---|---|---|
| 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. |
| 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. |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Functional Resistance Training With Brace Participants received functional resistance training while walking on a treadmill 2-3 times a week for 8 weeks.
Functional Resistance Training: A customized knee brace was strapped to the leg and applied resistance during knee flexion and extension while subjects walked on a treadmill. | 10 |
| Functional Resistance Training With Elastic Band Participants received functional resistance training while walking on a treadmill 2-3 times a week for 8 weeks.
Functional Resistance Training: An elastic band strapped to the ankle provided resistance during knee extension while subjects walked on a treadmill. | 10 |
| Control Participants walked on a treadmill without an applied resistance 2-3 times a week for about 8 weeks.
Control: A knee brace was strapped to the leg and did not apply resistance while subjects walked on a treadmill. | 10 |
| Total | 30 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 | FG002 |
|---|---|---|---|---|
| Overall Study | COVID-19 Research Shutdown | 0 | 2 | 2 |
Baseline characteristics
| Characteristic | Functional Resistance Training With Elastic Band | Total | Control | Functional Resistance Training With Brace |
|---|---|---|---|---|
| Age, Continuous | 22.1 years STANDARD_DEVIATION 4.5 | 20.4 years STANDARD_DEVIATION 5.4 | 20.4 years STANDARD_DEVIATION 5.6 | 18.8 years STANDARD_DEVIATION 6.2 |
| Height | 172.3 centimeters STANDARD_DEVIATION 7.9 | 172.0 centimeters STANDARD_DEVIATION 9.4 | 169.8 centimeters STANDARD_DEVIATION 9 | 174 centimeters STANDARD_DEVIATION 11.2 |
| Mass | 70.3 kilograms STANDARD_DEVIATION 12.2 | 70.2 kilograms STANDARD_DEVIATION 12 | 70.2 kilograms STANDARD_DEVIATION 13.3 | 70.1 kilograms STANDARD_DEVIATION 10.5 |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Asian | 1 Participants | 3 Participants | 2 Participants | 0 Participants |
| Race (NIH/OMB) Black or African American | 2 Participants | 3 Participants | 0 Participants | 1 Participants |
| Race (NIH/OMB) More than one race | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) White | 7 Participants | 24 Participants | 8 Participants | 9 Participants |
| Region of Enrollment United States | 10 participants | 30 participants | 10 participants | 10 participants |
| Sex: Female, Male Female | 6 Participants | 18 Participants | 6 Participants | 6 Participants |
| Sex: Female, Male Male | 4 Participants | 12 Participants | 4 Participants | 4 Participants |
| Time Since Surgery to Baseline Study Testing | 9.5 weeks STANDARD_DEVIATION 2.5 | 9.6 weeks STANDARD_DEVIATION 2.7 | 10.3 weeks STANDARD_DEVIATION 3.1 | 8.9 weeks STANDARD_DEVIATION 2.6 |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk |
|---|---|---|---|
| deaths Total, all-cause mortality | 0 / 10 | 0 / 10 | 0 / 10 |
| other Total, other adverse events | 0 / 10 | 0 / 10 | 0 / 10 |
| serious Total, serious adverse events | 0 / 10 | 0 / 10 | 0 / 10 |
Outcome results
Primary
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.
Time frame: 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.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Functional Resistance Training With Brace | Quadriceps Muscle Strength | .674 Nm/Kg | Standard Error 0.124 |
| Functional Resistance Training With Elastic Band | Quadriceps Muscle Strength | .398 Nm/Kg | Standard Error 0.13 |
| Control | Quadriceps Muscle Strength | .279 Nm/Kg | Standard Error 0.13 |
Secondary
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.
Time frame: 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)
| Arm | Measure | Value (MEAN) |
|---|---|---|
| Functional Resistance Training With Brace | Knee Flexion Angle Symmetry | 3.230 Angle Symmetry (degrees) |
| Functional Resistance Training With Elastic Band | Knee Flexion Angle Symmetry | 0.556 Angle Symmetry (degrees) |
| Control | Knee Flexion Angle Symmetry | 0.846 Angle Symmetry (degrees) |
Secondary
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.
Time frame: 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
| Arm | Measure | Value (MEAN) |
|---|---|---|
| Functional Resistance Training With Brace | Knee Moment Symmetry | .0144 Moment Symmetry (Nm) |
| Functional Resistance Training With Elastic Band | Knee Moment Symmetry | 0.132 Moment Symmetry (Nm) |
| Control | Knee Moment Symmetry | -0.042 Moment Symmetry (Nm) |
Secondary
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.
Time frame: Immediately after the intervention or approximately 18-20 weeks after ACL reconstruction
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Functional Resistance Training With Brace | Quadriceps Voluntary Activation | 73.19 percentage of activation | Standard Error 6.56 |
| Functional Resistance Training With Elastic Band | Quadriceps Voluntary Activation | 69.55 percentage of activation | Standard Error 7.72 |
| Control | Quadriceps Voluntary Activation | 68.29 percentage of activation | Standard Error 7.19 |