Introduction

Hello my name is Payton Heaney I am a grad student at Cal Poly Humboldt as well as a member of the women’s soccer team. So safe to say I love soccer it is not only a sport I love playing but it has also been one of the best teachers I have ever had. Playing soccer has driven me to be the person I am today. In this chapter I will discuss a few of the many ways that Neuromechanics impacts soccer. I hope this chapter gives you an insight into not only the wonderful world of soccer but also the fascinating impacts of neuromechanics on soccer.

Sensory Feedback

Soccer players are reliant on their sensory feedback in order to make adjustments to posture and balance, see the field, opponents and teammates, feel how they strike the ball, and knowing where they are on the field. Without proper feedback soccer players will be in the dark literally, having a decreased performance as well as a risk of injuries. Sensory feedback can be trained to help improve performance and lower injury rates. Without sensory feedback the levels of competitive and professional soccer would cease to exist.

Limited sensory feedback in soccer players will generally lead to a decrease in performance. Soccer athletes rely heavily on visual feedback in order to perform. This is extremely present in technical abilities with the ball. Fransen (2017) tested soccer players technical dribbling performance to the test using glasses to limit the vision of athletes performing the dribbling course. Fransen found that with limiting the vision of any athlete whether they performed in the “fast” or “slow” group in control trials the athletes performance decreased in time and performance. Fast dribblers tended to rely more on visual feedback in order to control the ball at a faster speed with accurate movements. Soccer athletes rely on sensory feedback to perform at a high level sensory feedback impacts every aspect of soccer. Dribbling being a specific example, ball mastery in general would be impossible without sensory feedback. Training proprioception which is a key factor in the sensory feedback system can majorly improve cognitive and actual performance.

Soccer players rely heavily on their proprioception to know where they are in time and space while other aspects of the game are going on congruently. If you have ever watched a Premier league or NWSL game (which if not you should) watch midfielders you can see them constantly scanning using their proprioception and visual inputs to know where they are on the field, where their teammates and opponents are on the field. Training sensory feedback can help improve the visual, vestibular and somatosensory. Focusing on proprioception training Evangelos et al(2012) found that after using proprioception, balance, and somatosensory activities using bosu, balance discs, togu, and trampoline to train balance led to a significant increase in amateur soccer players technical skills such as juggling, long passing, and short passing. Evangelos et al (2012) was supported by Paillard (2006) stating that when comparing international soccer players to smaller local league players the international players had attained a much higher level of balance. Going back to our example of high level midfielders constantly scanning to receive proprioceptive and visual information those athletes who have trained these skills will be much more successful cognitively and with their overall performance not only do they know where they are but their long and short passing is improved.

Training sensory feedback not only has a high impact on technical skills but training proprioception in specific can reduce injury risks. ACL (anterior cruciate ligament) injuries have a high rate in soccer. Cerulli (2001), explored using proprioceptive training in order to decrease the risk of ACL injury this training focused on the use of mechanoreceptors in order to know when a movement that is possibly threatening the ACL is happening and then to correct that movement. The training used weight bearing exercises and progressively reduced stability using a wobble board eyes open then closed. Cerulli tested 600 athletes 300 of which were placed in a control group doing traditional strength training while 300 were given proprioceptive training and all were tracked for 3 soccer seasons. 70 of the traditionally trained athletes suffered confirmed ACL ruptures while only 10 of the proprioceptively trained athletes suffered ACL ruptures. Proprioceptive training is an effective way to combat acl tears using sensory feedback in training to reduce the likelihood of season ending injuries.

Sensory feedback is necessary and important for high performance in Soccer players. Once again watch some NWSL and Premier league (Go Chelsea and Bay FC) Sensory feedback directly affects performance through proprioception, vision, tactile, vestibular systems. With limited visual sensory feedback athletes struggle to perform ball mastery tasks such as dribbling. When sensory feedback of proprioception is trained an increase in not only technical performance but a decrease of injury. Soccer players need sensory feedback in order to perform technical tasks as well as prevent injuries.

The Cortical System

The Cortical System is directly related to soccer as it controls important aspects of the sport such as visual processing, motor planning and execution, sensory integration, and cognitive function. Soccer also has an impact on cortical function from the use of headers.

Soccer players use visual processing to predict the future movements of opponents. A study Fooling the Kickers but not the Goalkeepers: Behavioral and Neurophysiological Correlates of Fake Action Detection in Soccer by Tomeo et al (2012)  it was uncovered that when tracking the cortico-spinal reactivity of kickers, goalkeepers, and novices to predict the direction of soccer-specific penalty kicks it was found both kickers and goalkeepers were able to more accurately predict the direction of the penalty kick by reading the body kinematics and using past visual cues when compared to novice. Which makes sense if you’ve ever seen a professional soccer penalty shoot out vs a youth recreation penalty shoot out the professional is DEFINITELY saving more then the youth players. Being able to use the cortical system in order to more accurately predict opposition movements in soccer allows players to have faster, more accurate movement reaction and preparation in order to counter opponents.

Soccer players constantly use the Cortical System to plan and execute movements. A commonly used movement in soccer is kicking the ball. In the study Modeling the relationships between EEG signals, movement kinematics and outcome in soccer kicking by Palucci Vieira et al (2022) This demonstrated the relationship between the cortical system and movement control, velocity, and accuracy when performing a goal specific kick. This study found that signaling at the cortical level plays an important role in determining velocity and accuracy factors in kicking. This study also determined that more frontal theta power during the impact phase as well as occipital alpha in the preparatory period predict a better performance of instep kicking. Soccer athletes depend on the cortical system to put practiced skills into motion. The cortical system allows them to adjust movements in order to use the best determined velocity and make the pass outcomes accurate.

Soccer athletes are impacted with negative effects on the cortical system due to the practice of headers. Heading the ball  is considered sub-concussive hits, some even concussive and or mild through severe traumatic brain injury; these can overtime cause cortical thinning. In a study by Koerte et al (2016) Cortical thinning in former professional soccer players. This study tested former professional soccer players’ cortical thickness, cognitive processing speed, and visual memory performance. This study uncovered that life-time estimate of headers was significantly correlated with cortical thickness specifically in the right hemisphere parietal and occipital lobes; the more repetitive sub-concussive head impacts or headers the thinner the cortex. A thinner cortex reflected a lower cognitive processing speed and lower visual memory performance (when compared to the control group of non-contact athletes). Sub-concussive head impacts are directly linked to cortical thinning and are reflected in early cognitive decline in soccer athletes and potentially an association to neurodegenerative disease. Headers overtime will begin impacting players’ movement because slower cognitive processing speed leads to slower reaction time, difficulty completing complicated tasks, and possible problems with coordination and balance.

Soccer is heavily reliant on the cortical system in order to successfully perform tasks. Athletes rely on the visual processing, motor planning and execution, sensory integration, and cognitive function provided by the cortical system. Over time soccer athletes are at higher risk for suffering cortical thinning as a result of the sport due to the practice of headers. So if you are an avid soccer player like I am please take those hits seriously if you feel symptoms of a concussion take it seriously. You only have one brain for your entire life.

Motor Output

Motor output is used in soccer athletes all the time. Soccer is a game full or reaction and action which is essentially what motor output is. If Messi couldn’t react quickly to visual stimuli would be the athlete we know and love no he wouldn’t. Motor output is our brain sending signals to out muscles in order to react to an external stimulus. We see this in our daily lives in reflexes, reaction time, and the speed-accuracy trade off.

When we are born we have certain primitive reflexes which as we grow and develop should develop into voluntary movement but for some people these reflexes can remain active into youth and adulthood these can have a detrimental effect on technical skills in soccer  Bastiere et al (2024) did the most interesting study on how active primitive reflexes impact technical skills in football (aka soccer if you didn’t already know this). They tested 58 academy players at a french professional club and tested them for primitive reflexes and set them in two separate groups APR or active primitive reflex and IPR or inactive primitive reflexes using the methodology established by Neurophysiological Psychology (INPP)( watch the video bellow for more clarity). Players were then broken up by specific positions. They analyzed these players over an entire football season success rates of various skills classified as TaS- tactical skills (based on passes made in different areas of the field and movements during defensive transitions) and TeS- technical skills (on ground 1v1s and aerial duels). Analysis of the Tes data showed that athletes in the APR group had a lower success rate by 34.2% for on ground 1v1s and 26.0% for aerial duels as well as a higher number of fouls by .4 fouls per 100 minutes of active playing time. TaS also showed lower success rates in the APR group in two passing zones as well as a lower success rate in players with APR with the average decrease of success being 25.5%. OK that was a lot I KNOW but think how interesting that is how our motor output can be impacted by reflexes we may have NO IDEA are still there and think how this can be used to determine teams athletes should be on rather then age groups because lets face it we have Lamine Yamal’s and Mel Barcenas’s now age is not a determiner of who can play pro its skill.

Reaction time is the time between the stimulus and the initiation of the response. Many studies have been performed to use reaction time as a predictor of change of direction (many of which are mostly on men which like COME ON we’ve got to get on some studies for women people) But moving on in a study for the Saudi Journal of Sport Medicine Homoud, Mohammed, Nawi, and Ridha (2015) took 20 male football (or soccer) from the first division using a 20 meter swerve sprint and the Illinois agility test to determine change of direction (COD) speed then used a software “reaction” to test reaction time. The study concluded that all factors of this study were positively correlated AKA they all affected each other. People with faster reaction times generally had faster COD speed. Players with a better reaction time can generally be predicted to be at the more elite level of athletics.

Another motor output consideration in soccer is the speed vs accuracy trade off this is that you can do something with completely perfect accuracy or something as fast as possible but not something at the same time. Like for example try to write your name as fast as you possibly can and I can bet you it will not be as accurate or well done as if you took your time. Van den Tillaar and Ulvik (2014) investigated how this trade off could affect soccer players shooting by looking at how instruction played a role into velocity and accuracy of 10 experienced male soccer players. They were given 4 different instructions  1. Kick the ball as fast as possible straight forwards in the goal 2. Kick the ball as fast as possible and try to hit the center of the target. 3. Hit the center of the target and try to kick the ball as fast as possible. 4.  Hit the center of the target the subjects did 8 kicks with each instruction on both feet. After all the trials were concluded and the data was analyzed the speed-accuracy tradeoff could be clearly seen. Van den Tillaar and Ulvik noted that when instructed to focus on accuracy a clear decrease in velocity was noted. AKA they saw the affects of the speed accuracy trade off.

Motor output can be seen in every single movement we make it literally is every voluntary movement we make and in soccer specifically it can have very interesting implications in skill level, reaction time, and shooting. I could go on all day about how important training all these actions and reactions are. And cool enough I work in a giant soccer facility in the bay area that uses these trainings constantly and get to be on projects to assess skill level.

References

Alanazi, Homoud, Mohammed Nawi, and Ridha Aouadi. “Reaction time as a predictor for change-of-direction speed in male soccer players.” Saudi Journal of Sports Medicine, vol. 15, no. 3, 15 Dec. 2015, p. 220, https://doi.org/10.4103/1319-6308.164287.

Bastiere, Julie, et al. “Active primitive reflexes obstruct tactical and technical skills in football players.” Journal of Sports Sciences, vol. 43, no. 2, Dec. 2024, pp. 162–172, https://doi.org/10.1080/02640414.2024.2434800.

Bekris Evangelos, Kahrimanis Georgios, Anagnostakos Konstantinos, Ioannis Gissis, Christos Papadopoulos Sotiropoulos Aristomenis (2012). Proprioception and balance training can improve amateur soccer players’ technical skills. The Journal of Physical Education and Sport, Vol 12 (Issue 13), pp.81-89.

Cerulli. G, Benoit. D.L., Caraffa. A, Ponteggia. F, (2001) Proprioceptive Training and Prevention of Anterior Cruciate Ligament Injuries in Soccer, Journal of Orthopaedic & Sports Physical Therapy,  Vol 31 (Issue 11), pp. 655-660.

Fransen, J, Thomas W.J. Lovell, Kyle J.M. Bennett, Dieter Deprez, Frederik J.A. Deconinck, and Matthieu Lenoir, Aaron J. Coutts (2017). The Influence of Restricted Visual Feedback on Dribbling Performance in Youth Soccer Players, Human Kinetics Inc., Vol 21, (Issue 2), 159-192. https://doi.org/10.1123/mc.2015-0059

Koerte, I. K., Mayinger, M., Muehlmann, M., Kaufmann, D., Lin, A. P., Steffinger, D., Fisch, B., Rauchmann, B.-S., Immler, S., Karch, S., Heinen, F. R., Ertl-Wagner, B., Reiser, M., Stern, R. A., Zafonte, R., & Shenton, M. E. (2015). Cortical thinning in former professional soccer players. Brain Imaging and Behavior, 10(3), 792–798. https://doi.org/10.1007/s11682-015-9442-0

Paillard T, Noé F, Rivière T, Marion V, Montoya R, Dupui P(2006). Postural performance and strategy in the unipedal stance of soccer players at different levels of competition. J Athl Train. 41(2): 172–176.

Palucci Vieira, L. H., Carling, C., da Silva, J. P., Santinelli, F. B., Polastri, P. F., Santiago, P. R. P., & Barbieri, F. A. (2022). Modelling the relationships between EEG signals, movement kinematics and outcome in soccer kicking. Cognitive Neurodynamics, 16(6), 1303–1321. https://doi.org/10.1007/s11571-022-09786-2

‌Tomeo, E., Cesari, P., Aglioti, S. M., & Urgesi, C. (2012). Fooling the Kickers but not the Goalkeepers: Behavioral and Neurophysiological Correlates of Fake Action Detection in Soccer. Cerebral Cortex, 23(11), 2765–2778. https://doi.org/10.1093/cercor/bhs279

Van den Tillaar, Roland, and Aleksander Ulvik. “Influence of instruction on velocity and accuracy in soccer kicking of experienced soccer players.” Journal of Motor Behavior, vol. 46, no. 5, 28 Apr. 2014, pp. 287–291, https://doi.org/10.1080/00222895.2014.898609.