Science of Feedback

Once a movement skill is performed it is appropriate for the coach to provide feedback to the athlete. Feedback refines the motor system by guiding the athlete towards a movement pattern in a manner that promotes implicit (self-correcting) processes. Feedback is classically broken down into two categories comprised of task-intrinsic feedback (TIF) and augmented feedback (AF) (see Figure 2) (10).  

Figure 2. Feedback Model adapted from Magill 2011 

TIF is considered information that is obvious to the athlete and is received across visual, auditory, tactile, and proprioceptive sensory inputs. Providing feedback on information that is apparent to the athlete can be considered redundant and therefore can be avoided (11). We know that working memory and attention are limited in capacity (13) and for this reason it is critical that we limit information to what is necessary for the athlete’s success. 

AF, on the other hand, provides information to the athlete that is not currently known and can be broken down into the following categories: 

• Knowledge of Results (KR): Information about the outcome of a movement task or if a goal was achieved (e.g. 40 yard sprint time or ball location on the golf fairway for a dogleg left shot)
• Knowledge of Performance (KP): Information about the movement qualities that led to the performance outcome (e.g. “you came up to quickly out of your 3pt stance” or “you were to early on your second pull during the snatch”)

The following section will discuss the application of AF as it relates to feedback timing, frequency, content, and methods. 

Feedback Timing

Feedback timing is broken into two categories where concurrent feedback is given during the task and terminal feedback is given after the task. While there is limited research in the area of concurrent feedback the majority of research has shown that concurrent feedback may have a negative affect on retention and transfer of movement skills (14, 16, 20). Providing feedback during a movement becomes a distraction that increases conscious thought and can take away from movement efficiency and implicit learning. 

Research on concurrent feedback has shown potential benefits for the use of mirrors in novice athletes learning a weightlifting skill (18) and auditory feedback used during a repetitive gymnastic skill (2). Concurrent feedback from mirrors may help the athlete identify with the feeling of certain positions that are critical to the movement being taught (e.g. Weightlifting). 

This positional awareness and increase in kinesthetic sense will help them self-correct when mirrors are no longer available. Concurrent auditory feedback may have strong application within coaching repetitive movement skills. 

Many speed development drills are dependent on specific rhythm and tempos. A case can be made that auditory cadences can be used during various skipping patterns, acceleration and absolute speed sprint drills. For example, it is common for a novice sprinter to use excessive stride frequency during the acceleration portion of a 40yd sprint. A coach may use specific auditory cues such as “push, push, push” to match the desired frequency of the first three contacts out of a start stance. 

A case can be made that this generates a context for the cadence of the movement skill, but does not disrupt learning by providing detailed information about the pattern itself (i.e. internal cueing). 

Feedback Frequency

Terminal feedback is provided after a movement skill is performed and has been well established within the literature (9). What has come into question is the frequency with which KR and KP should be given to the athlete. Logic would say that the more feedback we receive during practice the better the learning effect, but in adopting this absolute view we would find our logic to be flawed. 

Winstein and Schmidt (21) examined the difference between providing feedback on 100% versus 50% of trials while subjects learned a novel movement pattern. Across three experiments they found that providing feedback on 50% of trials was superior to 100% of trials. 

Meaning that the initial trials would have received 100% feedback and later trials may only receive 33% feedback with the total feedback across practice being 50% of total trials. 

Over the last two decades, research has continued to support the notion that feedback should not be given on 100% of trials (1, 12, 14, 17, 25). In support of the conclusion that a reduction in terminal feedback improves retention and transfer of learning Salmoni and colleagues (15) proposed the guidance hypothesis, stating that feedback guides learning during skill acquisition, but if given too often can create “feedback dependency” resulting in decreased performance when the feedback is removed (10, 22). We see this hypothesis realized frequently within a sport context. 

An athlete is exposed to a coach that provides frequent feedback with good intentions. The athlete is able to practice very well and develops a need for feedback on every repetition. The problem arises when that athlete has to perform in competition and no longer has access to immediate feedback. To generate success in sport we must use feedback frequencies that improve an athlete’s ability to implicitly self-correct in an effort to move them towards higher levels of automatic processing. 

As coaches we must realize that what we say is as important as what we don’t say and as an athlete progresses it is critical that we allow them to make mistakes and problem-solve. 

Feedback Content

While researches collectively agree with the guidance hypothesis, there is research to show that it is not only the frequency with which feedback is given, but also the content of the feedback. Wulf et al. (24) looked at internal versus external focus under 33% and 100% feedback frequencies for a soccer passing accuracy test. 

Results were significant and found that an external focus with 33% and 100% feedback resulted in superior accuracy compared to both internal conditions during practice and retention. 

What should be noted is that accuracy was significantly higher during the 33% internal condition compared to the 100% internal condition. The results of this study are important as the authors showed that 100% feedback can be given when the message is an external focus, but in the case of an internal focus the guidance hypothesis is in effect and feedback frequency should be reduced. 

Recent work by Wulf and colleagues (23) continues to reinforce that feedback frequencies should be evaluated as a function of the feedback content.

From an applied standpoint we know that coaches will typically cue movement positions and movement patterns. Our current knowledge would say that we should use external focus cues when providing feedback on the dynamics of the movement pattern, but less is known about cuing movement positions. 

From a squatting standpoint coaches will typically cue “chest up”, “hips back”, “core tight”, “weight on the heels”, etc. By our definition all of these cues would be internal and based on the research presented we would have to challenge their efficacy. The author’s belief is that while external focus cues should be directed at the movement pattern, internal or external focus cues can be used for movement positions. 

The reasoning is that these are set-up cues which should not disrupt the dynamics of the movement pattern being performed. 

Feedback Methods

In an effort to decrease feedback frequency various feedback methods have been proposed for use in applied settings. The following feedback methods are represented in the literature and have applied merit (10): 

• Bandwidth Feedback: Feedback is given when a performance error exceeds a pre-determined range. Performance errors can relate to qualitative performance (e.g. movement pattern) or quantitative results (e.g. movement time). (Example: A coach will only give feedback during a sprint when time drops below a 10% bandwidth or a coach will only give feedback when a specific error is seen during the power snatch) (19).
• Summary Feedback: Feedback is given after a series of trials (i.e. <100% feedback frequency) and a summary of KR or KP from every trial is provided. This method decreases feedback frequency, but still delivers the same amount of information as 100% feedback frequency. (Example: An athlete would perform 3-5 repetitions of a movement and then the coach would provide feedback in reference to each repetition) (17, 21, 26).
• Average Feedback: Feedback is given after a series of trials and average KR or KP across trials is provided. This method decreases feedback frequency and provides feedback on the average performance errors or results across trials performed. (Example: An athlete would perform 3-5 repetitions of a movement and then the coach would provide feedback on the most common error seen over the repetitions) (17, 21, 26).
• Fading Feedback: Feedback is given at higher frequencies at the beginning of a skill acquisition session (i.e. 100%) and fades as the session progresses (i.e. 33%). This fading can happen across trials within a session or across multiple sessions. (Example: Coach might give feedback on every repetition during sets 1-5 of a weightlifting session, feedback on 50% of repetitions for sets 6-10, and feedback on 33% of the repetitions for sets 11-15) (21).
• Self-Selected Feedback: Feedback is given at the request of the learner in response to their perception of a bad trial, a good trial, or when they are unsure (Example: Coach would preface the session telling the athletes that feedback will only be provided at the request of the athlete) (3-8).

Conclusion

This paper proposed underlying mechanisms and application in relation to instruction and feedback as critical components within the science of coaching. These methods were highlighted as potential limiting factors in the effective delivery of training methods from coach to athlete.

Table 2 provides a framework for applying instruction and feedback. From an instruction standpoint expert demonstration should be used during initial learning. As the athlete improves their ability to identify environmental cues and self-correct, the use of novice demonstration will improve problem solving capabilities. 

Within the instruction model the use of verbal instruction should focus on up-regulating the use of external focus cues and analogies while decreasing internal cueing. Feedback should be provided terminally unless concurrent feedback is used to support cadence. Task-intrinsic information that is redundant should be avoided and therefore augmented feedback should focus on KR and KP that is unknown to the athlete.  

Table 2. Instruction and Feedback Framework 

During initial learning feedback should primarily focus on KP as this will improve the athlete’s knowledge of how to perform and improve a movement skill. As the athlete moves towards automatic processing they can readily self-correct their movement performance and will depend on KR as the primary feedback form. Within the delivery of feedback the message should be focused on top priority corrections and delivered with an external focus. 

Despite research showing that external focus feedback can be given 100% of the time there is still strong evidence to show that feedback frequency should decrease from 100% to 33-50% of absolute repetitions as the athlete moves towards automatic processing. All of these recommendations come with the understanding that to reach the highest level of sport an athlete must be able to express their skill in complex environments, with high levels of autonomy, and minimal coach interaction. 

Therefore our coaching must evolve to provide instruction and feedback methods that hand “the keys to the car” over to the athlete and allow them to own their skill. While this is difficult for coaches, it comes with the understanding that knowing when to communicate is as important as knowing when not to.

In summary, the science of coaching provides coaches with critical insights on how to optimize the delivery of information to maximize the effect of the training methods used. While this paper was not an exhaustive review of all components within coaching science, it will provide coaches with critical insights that can have an immediate affect on their athlete’s performance. 

References

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About the Author

Nick Winkelman is the Director of Training Systems and Education for Athletes’ Performance. He oversees their NFL Combine development program in addition to directing the education department. He has a MSc through Edith Cowan University and is currently completing his doctorate through Rocky Mountain University of Health Professions with an emphasis in coaching science.