When to Use and Remove Biofeedback – Principles of Motor Learning Part 2

By |2023-10-02T11:23:49-04:00October 29th, 2023|Latest Articles|

Motor learning is defined as the acquisition of skilled movement as a result of practice.(1) In Part 2 of this blog post we will continue to look at how feedback schedules, type of feedback, and practice patterns can be used to maximize the benefits of mTrigger biofeedback.

If you haven’t already, be sure to check out Part 1 of this blog post first!


Knowledge of performance provides information about the specific movement component characteristics that led to the performance outcome.(2) For instance, a video. This type of feedback is helpful when learning a very specific (and tricky) movement such as in gymnastics, diving, or stunts, where a specific part of the skill requires very complex coordination to be improved upon or corrected.(2) In this case, the skill being learned requires a very specific kinetic, kinematic, or muscle activity.(2) Knowledge of performance does not specifically provide information on the outcome of the movement or task.

This video provides an example of knowledge of performance feedback using the mTrigger device as seen in the “Train” mode. While performing a tempo squat, the patient is receiving information regarding weight shift and symmetry of movement. 

Knowledge of results provides information related to the performance outcome.(2) This is a great way to help learners confirm their own assessment of the task performance.(2) It also motivates learners to continue practicing in order to achieve the desired outcome.(2) Knowledge of results will let the patient know how they did in relation to the movement goal. In the case of mTrigger, the “Track” screen provides knowledge of results in relation to the exercise MVC goal. Knowledge of results does not provide information about the motor pattern.

Here is an example of receiving knowledge of results using the mTrigger device. The patient only sees the outcome in the “Track” screen after they have completed the exercise.

When it comes to acquiring a motor skill, both knowledge of performance and knowledge of results can enhance motor learning. There is some evidence however, that knowledge of performance is more influential than knowledge of results.(2)

Regardless of the type of feedback, it is important to understand how much feedback should be provided. Providing 100% knowledge of results can be detrimental to learning a skill as the patient becomes fully reliant on that feedback.(3) The ideal amount of feedback falls on a sliding scale. The more difficult a task, the higher the frequency of feedback necessary for learning, usually a minimum of 50% feedback.(3,4) For an easier task, less frequent feedback is adequate to promote learning, usually between 33-50%.(3,4)


In a study on knee OA, researchers used biofeedback during their rehab interventions to help re-establish proper movement patterns. Initially when starting out, biofeedback was necessary and used almost all the time. After a period of time, biofeedback was decreased to 50% and incorporated with random practice of the exercise to help promote retention.(5) Once patients were able to perform the exercise with less than 5% asymmetry between limbs, the difficulty of the exercise was progressed to a point where the patient needed biofeedback again to perform the movement correctly.(5) At this point, biofeedback was introduced in high volumes again to help with initiating the proper movement pattern.(5) After which the same removal of feedback process was started. This intermittent biofeedback is an excellent way to promote both motor learning and increase motivation in our patients.(5)

In the example below, the patient is struggling to perform a symmetrical squat without weight shifting. mTrigger biofeedback is being used initially during the entire exercise to help teach proper movement. Over the course of the next several weeks, biofeedback was decreased and eventually removed before being utilized again for another challenging exercise such as a lateral step up. 

In another study involving soccer players learning the motor skill of a thrown in, the retention scores were highest when 50% frequency in knowledge of results was given.(6) Similar to previous studies, a moderate frequency of feedback helped to enhance learning.


When selecting the type of feedback, it is important to consider the difficulty level of the exercise or motor skill. If the task is more difficult, then, more feedback will be needed up front.(7) Furthermore, starting with blocked practice, progressing to serial, and then moving to random practice, can help patients learn the skill and improve their long-term retention.(8) A more difficult exercise for a novice learner may also need to initially be broken down into part practice before progressing to whole skill practice. Ultimately, to promote motor learning and retention, the goal is to perform whole exercise practice in random order.(9) Finally, as exercise programs are progressed and new movement patterns introduced, don’t forget to bring back mTrigger biofeedback to enhance learning.


Knowing when to use mTrigger biofeedback and subsequently when to remove it once an exercise gets easier is key to helping your patient’s retention of an exercise or motor pattern. Understanding how best to use practice schedules and different types of feedback can also greatly improve the learning experience for your patients as well as their outcomes.


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1. Winstein CJ. Knowledge of Results and Motor Learning—Implications for Physical Therapy. Phys Ther. 1991;71(2):140-149. doi:10.1093/PTJ/71.2.140
2. Sharma DA, Chevidikunnan MF, Khan FR, Gaowgzeh RA. Effectiveness of knowledge of result and knowledge of performance in the learning of a skilled motor activity by healthy young adults. J Phys Ther Sci. 2016;28(5):1482-1486. doi:10.1589/JPTS.28.1482
3. Sidaway B, Bates J, Occhiogrosso B, Schlagenhaufer J, Wilkes D. Interaction of Feedback Frequency and Task Difficulty in Children’s Motor Skill Learning. Phys Ther. 2012;92(7):948-957. doi:10.2522/PTJ.20110378
4. Elghoul Y, Bahri F, Trabelsi K, et al. Optimizing Motor Learning: Difficulty Manipulation Combined with Feedback- Frequency Enhance Under-Time-Pressure Fine-Motor-Coordination Skill Acquisition and Retention. J Mot Behav. 2022;54(4):490-502. doi:10.1080/00222895.2021.2016573
5. Bade MJ, Christensen JC, Zeni JA, et al. Movement Pattern Biofeedback Training after Total Knee Arthroplasty: Randomized Clinical Trial Protocol. Contemp Clin Trials. 2020;91:105973. doi:10.1016/J.CCT.2020.105973
6. Hebert EP, Coker C. Optimizing Feedback Frequency in Motor Learning: Self-Controlled and Moderate Frequency KR Enhance Skill Acquisition. Percept Mot Skills. 2021;128(5):2381-2397. doi:10.1177/00315125211036413
7. Kafri M, Atun-Einy O. From Motor Learning Theory to Practice: A Scoping Review of Conceptual Frameworks for Applying Knowledge in Motor Learning to Physical Therapist Practice. Phys Ther. 2019;99(12):1628-1643. doi:10.1093/PTJ/PZZ118
8. Pauwels L, Chalavi S, Gooijers J, et al. Challenge to Promote Change: The Neural Basis of the Contextual Interference Effect in Young and Older Adults. J Neurosci. 2018;38(13):3333-3345. doi:10.1523/JNEUROSCI.2640-17.2018
9. Sattelmayer M, Elsig S, Hilfiker R, Baer G. A systematic review and meta-analysis of selected motor learning principles in physiotherapy and medical education. BMC Med Educ. 2016;16(1). doi:10.1186/S12909-016-0538-Z

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