Application of Closed-Loop And Open-Loop Control Systems
Closed-loop and open-loop control systems, what? These systems are the systems that allow us to perform movements and not just in sports or dance. Each system serves a purpose and aids performers in taking effective action in their chosen sport. Let’s learn some more about them and the importance of understanding both systems.
Closed-Loop Control System
Components
This section is information dense and focuses heavily on biology terms. Be prepared! If you would like to skip this section and read the weakness and strength bullet points in their respective sections, you will still learn something you can apply to your life. Everyone once in a while it is fun for me to share a bit of biology. Thanks for understanding! There are four components to a closed-loop control system: executive, effector, comparator, and feedback (Schmidt & Lee, 2013). The executive system consists of the processes surrounding stimulus identification, response selection, and movement programming stages. The commands generated in the executive are then sent to the effector system. There, the motor program produces commands for lower centers in the spinal cord, which results in muscle contractions and joint movements. While this process occurs, information is specified to delineate the sensory qualities of the necessary movement, which is the performer's anticipated sensory feedback or what sensations should be generated if a movement is correctly executed. The movement or output produces proprioceptive and exteroceptive feedback information or movement-produced feedback. Take muscle contraction as an example. Feedback is delivered to the system about forces and the pressure exerted on objects in contact with the skin. The muscle contracts create movement, which results in feedback from the moving joints and body position changes related to gravity. Regarding the external environment, movement creates alterations, which the receptors for vision and audition sense, providing even more feedback to the system. The movement-produced stimuli are then compared against their anticipated states in the comparator. If there is any difference, that represents the error that needs to return to the executive. Through this process, behavior is refined and maintained, keeping errors at low levels.
Weaknesses
Closed-loop motor control has two weaknesses:
It is slow because it has go through every stage again
There are attentional requirements.
An example of the attentional weaknesses in action. To be successful, athletes must rapidly perceive the positions and movements of teammates and opponents in addition to the ball, attend to the most relevant features of the game, and make correct decisions (Hüttermann et al., 2019; Klatt & Smeeton, 2020). If there are already multiple attentional demands for the performer, asking for an attentional resource is not adequate for completing the movement.
An example of the slowness weakness in action. There is flexibility in movement control because of the stages of information processing that allow for alterations in the movement, the stages or in the process are slow (Sehara et al., 2019). During times of high demand for processing time or resources, the stages are particularly slow, especially for creating complex actions. In a closed system, the stimulus itself is the error that drives the executive, while the correction is the selected movement. The rate at which this system works has a maximum correction of three per second. Each correction comes from errors over the past few hundred milliseconds and moves through the identification, response, and selection stages before moving to movement programming. Because of this process, tracking tasks involving more than three direction changes per second are not performed well. In certain sports, every second makes a difference.
Strengths
Closed-loop motor control has two strong strengths (Becker & Person, 2019):
The enablement of precise control.
The execution of novel movements.
Because of the system's ability to take feedback and make corrections, this system is suitable for learning new skills or for the execution of skills rarely needed.
Open-Loop Control System
Components
Again, this section is information dense and focuses heavily on biology terms similar to above. Same heads up applies! The open-loop system comprises two parts, the executive and the effector (Schmidt & Lee, 2013). This system works by accepting input about the desired state being presented to the executive level to define the necessary action. The instructions are then given to the effector level, which executes the instructions and completes the system's role. Movements that employ the open-loop system tend to occur when the performer does not have time to process information about errors and where movements must be planned entirely before initiation. This is where practice plays a key role in creating learned skill actions so that performers can create stable, precise, and longer-operating motor programs. These can then be accessed from long-term memory and prepared for during the response programming stage.
Weaknesses
Open-loop motor control has three distinct weaknesses:
The skill program contains errors. A performer cannot adjust and may not be aware that a mistake has been made.
Developing open-loop control of the desired motor skill demands much practice.
When a novel or new situation is introduced, the system does not know how to handle it.
Strengths
Open-loop motor control has two strengths:
It is fast, allowing for muscle movements to happen in tens of milliseconds.
It does not tax the attentional system, as movements in this system happen automatically.
Let’s look at an example to understand how these two systems work together. A kickboxing kick beautifully exemplifies how the components of the two systems work together. A performer moving through a kick against a punching bag activates the open-loop system through the movement of the kick, and the postural maintenance activates the closed-loop system. These two systems need to work together to accomplish this task and find a solution to the motor problem (Muratori et al., 2013).
If you want the full blow by blow read the following, but if you don’t want the full breakdown skip to the Application for Performer Improvement sectional It will not hurt my feelings if you want to skip this section.
The control of posture while ensuring its stability is a fundamental task of the central nervous system (Błaszczyk et al., 2020) and is the aspect most likely monitored by the closed-loop system. Beginning with the executive system, the performer takes in stimulus information which may be the gym, the equipment, the task to kick, the potential transition from two feet to one, or any other surrounding sounds or people. The information then moves through the response selection and movement programming stages to begin programming before moving to the effector system. Once in the effector system, the command about how posture needs to be maintained is produced, asking the muscles and joints to move. However, at the same time, the closed-loop system has information about what should be happening to maintain an upright posture from the start of the kick to the end and also gathers proprioceptive and exteroceptive feedback from what is occurring. A comparison occurs to see if there is an error occurring such as even slightly leaning to the side just enough to throw the performer off balance in the comparator system. If there is indeed an error, that feedback is sent back to the executive to go through the process again to help realign the posture to stay upright. There are several places where errors may occur during a kick as the leg lifts, extends, and lowers. If the above process is done well, an outside observer may see a reorientation of the segments pelvis, lumbar and thoracic spine, and head to each other through the involvement of corresponding muscles bringing the respective joints, hip, shoulder, and upper cervical, closer to a common plumb line (Ludwig et al., 2020).
The execution of the kick component of the movement can be divided into three phases (Picone et al., 2021). They are as follows: loading, discharge, support foot orientation, and reload. Assuming that this performer is skilled and has practiced their kick, the open-loop system may dominate. The executor takes in the input discussed above in the posture discussion to define the actions needed to execute the kick. These instructions are sent to the effector level, which then executes the kick. In performing a kick, the performer does not have the time to process error information as the action is quick and powerful. However, the performer does have the ability to have the kick phases mentioned above preplanned.
Application for Performer Improvement
It is potentially the convergence of both the open and closed-loop systems that create motor behavior. Studies have demonstrated that both closed and open loops and merging both have a positive effect on the performance level (Abu Maaty & Adib, 2011). However, it is the correct application of instruction that may lead to that effect. For example, knowing the difference between open- and closed-loop systems may guide the application of internal and external types of focus and take advantage of attentional demands when working to acquire new skills. The open-loop system happens unconsciously and as an athlete becomes more skilled and the skill becomes more unconscious, potentially accessing that system suggests an external focus may be of benefit.
Person jumping with right leg out and right leg bent.
take action today moment:
If you have made it to this section, thank you for sticking with it. Since you have already done so much reading, let's get right to it. Think about what type of focus you need to use to build a new movement skill. Use the blog post on attention linked here to craft a strategy to exercise your attention so that you can be effective in learning movement skills.
Learn More About the Winter Solstice:
Open-Loop and Closed-Loop Control Systems
References
Abu Maaty, M. T., & Adib, J. N. (2011). Effect of using closed loop theory on performance level of some basic skills of table tennis juniors. World Journal of Sport Sciences, 5(2), 131-134.
Becker, M. I., & Person, A. L. (2019). Cerebellar control of reach kinematics for endpoint precision. Neuron, 103(2), 335-348.
Błaszczyk, J. W., Fredyk, A. F., Błaszczyk, P. M., & Ashtiani, M. (2020). Step response of human motor system as a measure of postural stability in children. IEEE Transactions on Neural Systems and Rehabilitation Engineering, 28(4), 895-903.
Hüttermann, S., Smeeton, N. J., Ford, P. R., & Williams, A. M. (2019). Colour perception and attentional load in dynamic, time-constrained environments. Frontiers in Psychology, 9, Article 2614.doi: 10.3389/fpsyg.2018.02614
Ludwig, O., Kelm, J., Hammes, A., Schmitt, E., & Fröhlich, M. (2020). Neuromuscular performance of balance and posture control in childhood and adolescence. Heliyon, 6(7), E04541.
Klatt, S., & Smeeton, N. J. (2020). Visual and auditory information during decision making in sport. Journal of Sport & Exercise Psychology, 42, 15–25. doi: 10.1123/jsep.2019-0107
Muratori, L. M., Lamberg, E. M., Quinn, L., & Duff, S. V. (2013). Applying principles of motor learning and control to upper extremity rehabilitation. Journal of Hand Therapy, 26(2), 94-103.
Picone, A. D., Iona, T., Rigon, M., & Aliberti, S. (2021, June 21). The importance of balance with the prescriptive teaching in kickboxing [Conference paper]. Supplementary Issue: Spring Conferences of Sports Science. Costa Blanca Sports Science Events, Alicante, Spain.
Schmidt, R., & Lee, T. (2013). Motor learning and performance with web study guide: From principles to application (5th ed.). Retrieved from https://redshelf.com
Sehara, K., Bahr, V., Mitchinson, B., Pearson, M. J., Larkum, M. E., & Sachdev, R. N. (2019). Fast, flexible closed-loop feedback: Tracking movement in “real-millisecond-time”. Eneuro, 6(6), 1-18.