Home > Knee Injury, Movement Dysfunction > Use of Visual and Verbal Feedback to Improve Lower Extremity Biomechanics, Pain and Function

Use of Visual and Verbal Feedback to Improve Lower Extremity Biomechanics, Pain and Function

Reference:

Willy RW, Scholz JP, Davis IS.  Mirror gait retraining for the treatment of patellofemoral pain in female runnersClin Biomech (Bristol, Avon). 2012 Dec;27(10):1045-51. doi: 10.1016/j.clinbiomech.2012.07.011.

http://www.ncbi.nlm.nih.gov/pubmed/22917625

What issue was addressed in the study, and why?

Increased contralateral pelvic drop, hip adduction and hip internal rotation are commonly described movement dysfunctions in those with patellofemoral pain (PFP) during functional tasks.  Weakness of the gluteal muscles, which help to stabilize the aforementioned motions, is also observed in those with PFP. However, previous research indicates that isolated hip muscle strengthening is not an effective method for altering lower extremity movement patterns.  Thus, alternative interventions appear to be necessary to ultimately improve these dysfunctional movement patterns.

Real-time feedback using motion analysis has been shown to be an effective means to alter lower extremity movement patterns during running.  In this previous research individual’s lower extremity biomechanics were monitored using an optical motion analysis system while subject’s received real-time feedback on their movement patterns.  A limitation of this research is that it is not clinically feasible to incorporate optical motion analysis equipment for real-time feedback in clinical settings.  Visual feedback using a mirror is a clinically feasible mechanism to provide real-time feedback on lower extremity movement patterns.  However, research has not investigated the effects of visual feedback provided by a mirror on lower extremity biomechanics during running.  Therefore, the purpose of this study was to examine the effects of a 2-week mirror gait retraining intervention on lower extremity biomechanics during running.  In addition, this study investigated whether the effects of mirror gait retraining were transferred to other functional tasks (single leg squatting and stair descent) and retained (1-month and 3 month retention periods).

Who were the participants in the study?

Ten females completed the study and met the following criteria: self-rated patellar pain of at least a 3 out of 10 scale during running, symptoms must be present during running and at least one other activity (squatting, jumping, kneeling, prolonged sitting, stair descent).  Individuals with patellofemoral instability or other knee related pathologies or history of lower extremity surgery were excluded from the study.

What did the researchers do for this study?

Lower extremity biomechanics were quantified using a motion analysis system during 3 tasks: running, single leg squat, and stair descent.  Lower extremity function was quantified using the Lower Extremity Functional Scale.  Pain was quantified using a visual analog scale.  These measures were take at 4 time periods: pre-training, immediately post-training, 1-month post-training, and 3-months post-training.

Participants who demonstrated abnormal hip motion (greater than 20-deg of peak hip adduction) during running were asked to participate in the mirror gait retraining intervention.  Those who met the criteria participated in a 2-week mirror gait retraining intervention where individuals trained 4 days each week (8 total training session).  The mirror gait retraining intervention was conducted as follows:

  • Subjects ran on a treadmill while observing themselves in a full length mirror in front of them (visual feedback).
  • During running the subjects received the following verbal cues: “Run with your knees apart with your kneecaps pointing straight ahead” and “Squeeze your buttocks”
  • No other concurrent interventions (e.g. stretching, strengthening, etc) were performed
  • During the first week of training the amount of visual and verbal feedback was increased each session.
  • During the second week of training the amount of visual and verbal feedback were steadily decreased across each session.  This was performed to shift the individual’s dependence from external cues (verbal and mirror feedback) to internal cues and reinforce motor learning of the new movement patterns.  During the sessions when subjects received less feedback they would receive intermittent feedback during the training session.
  • The duration of each training session was gradually increased from 15 to 30 minutes over the 2-weeks.
  • The participants were instructed to not run outside of their training sessions during the 2-week intervention period.

What new information was learned from this study?

Running Biomechanics:

The following variables were significantly improved immediately following the intervention: peak hip adduction angle, peak thigh adduction angle, peak hip abduction moment, and contralateral pelvic drop.  However, there was no change in hip internal rotation.  After 1-month the following variables remained unchanged from post-test (suggesting successful retention of movement patterns): contralateral pelvic drop, peak thigh adduction moment, and peak hip abduction moment.  Thus, changes in peak hip adduction angle were not retained after 1-month of not performing the intervention.  After 3-months the following variables remained unchanged from post-test (suggesting successful retention of movement patterns): contralateral pelvic drop and peak thigh adduction angle.  Thus, changes in peak thigh adduction angle were not retained after 3-months of not performing the intervention.

Single Leg Squat Biomechanics:

The following variables were significantly improved immediately following the intervention (suggesting successful transfer of the new motor patterns during running to other functional tasks): peak hip adduction angle, peak thigh adduction angle, and peak hip abduction moment.  After 1-month the following variables remained unchanged from post-test: peak hip adduction angle, peak thigh adduction angle, and peak hip abduction moment.  After 3-months the following variables remained unchanged from post-test: peak hip adduction angle and peak thigh adduction angle.  Thus, changes in peak hip and thigh adduction were retained after 1 and 3-months of no training.  However, changes in peak hip abduction were retained after 1-month of no training, but not after 3-months of no training.

Stair Descent Biomechanics

Only peak hip adduction angle was significantly improved immediately following the intervention.  Thus, changes in peak hip adduction angle were transferred from running to stair descent; however, none of the other variables that were changed during running were transferred to stair descent.

Pain and Lower Extremity Function

Both pain and lower extremity function were significantly improved immediately after the intervention.  These improvements were retained at both the 1-month and 3-month follow periods.

What are the clinical applications of this study?

The findings indicate that the 2-week mirror gait re-training program was able to successfully improve hip biomechanics during running.  Also, many of these changes were successfully transferred to other functional tasks (single leg squat and stair descent).  Several of these changes were retained in all tasks.  In general, these findings suggest that the 2-week mirror gait re-training program used in this study was able to facilitate learning a new movement pattern (successful transfer and retention of new movement patterns).

In addition to improved movement patterns, pain and lower extremity function were also improved.  These findings suggest that improvements in pain and function may be associated with lower extremity movement pattern modifications.

Use of verbal feedback in combination with mirror gait retraining may be an important adjunct to a comprehensive and integrated intervention strategy to improve lower extremity biomechanics in those with PFP and altered hip biomechanics.

What are the limitations of the study, and what areas should be considered for future research?

There was no control group utilized in this study.  Thus, it is not clear if changes in lower extremity biomechanics, pain, and lower extremity function were due to the intervention.  However, these findings provide initial evidence to suggest that the intervention utilized in this study may have clinical merit and warrants further investigation.

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