“Language makes infinite use of finite media” – Alexander von Humboldt. It is impossible to become literate without a firm grasp of grammar. This truth holds equally for the field of human movement. In this specific domain the concepts of 'grammar' and 'literacy' go hand in hand. Each concept offers a unique perspective and contributes to an integrated and wholeistic approach to performance training. Each facet of this approach cannot stand on its own. Standalone grammar, in its isolation, merely amounts to a collection of rules and random words devoid of structure fail to convey meaning. These elements, although seemingly distinct, are in fact interconnected, aligning beautifully under the dual prism of science and art. In this context, 'science' predominantly enriches the 'grammar' of training, whereas 'art' infuses the aesthetic dimension into the language of exercise. Movement Literacy. Let's start by exploring the framework of physical literacy. In essence, movement literacy provides us with the vocabulary of human motion, encoding the broad repertoire of actions that our bodies can perform. These 'words' of movement — walking, running, jumping, pivoting, squatting, lunging, twisting, reaching, punching and so on — are the fundamental units that allow us to 'read' and 'write' within the language of physical activity. From the viewpoint of training applied both to sport and rehabilitation, physical literacy underlines the necessity of mastering the extensive array of movements as an integral part of enhancing performance, ensuring safety and accelerating recovery. Training Grammar. On the other side of the equation lies the grammar of training — the scientific basis of programming, or perhaps more accurately described, the analytical foundation of it. This involves the selection and sequencing of suitable sets, reps, load parameters, ranges of movement and variability level of a given method. Above all, it includes the intensity and specificity of selected exercises. These elements serve as the 'syntax' and 'rules' that govern the language of human motor behaviour. They also point towards the suitable level of mechanical and cognitive stress required to ensure long-term learning and retention of movement skills. Harmony of Two. While each pillar stands tall in its own right, they resonate more powerfully when harmonised — much like the union of melody and rhythm in a bouncy tune. Behind every stellar musical performance, not only lies the fundamental understanding of music theory, but also the artistic skill to weave it all together. In a similar way every single training program should be adjusted adequately to a bigger picture, called composition, which unveils the right meaning of sporting demands. Whenever when we look at successful and expert coaches more often we get inspired by the humanistic attitude, beauty and emotions that speaks through the modalities they use, than by the numbers behind it. ■ Literacy and grammar as fundamental aspects for meaningful communication. □ When this analogy is translated into the field of human movement science, it may help to seek more balanced, individualised and context-driven approach to sports rehabilitation and performance training. □ The scientific part is more evident in the grammar of training. It ensures a systematic, data-driven approach, which aids in the precise quantification and manipulation of the training process. This approach underscores the importance of empirical evidence and rigorous testing to guide training decisions and ensure athlete safety and effectiveness. □ Simultaneously, the artistic dimension, embodied by the literacy of physical activity, acknowledges the individual nuances of each athlete and their unique symphony of motion. It appreciates the fluidity, variability and expressiveness of human movement and it recognises that each athlete has a distinct 'style' or 'handwriting' of his or her athletic motion. Fluency. The fusion of these two elements transcends the conventional boundaries of training practices. This individualisation opens up a world of possibilities for customisation and refinement, lending an artistic creativity to the otherwise strictly scientific protocol. It provides a rich, dynamic, and flexible foundation for crafting programs that not only enhance physical performance and foster faster rehabilitation, but also cultivate a deeper, more nuanced understanding of the body's capabilities. This is not just about programming for athletic performance – it’s about composing a symphony of motion, a unique melody that sings to the rhythm of each athlete's body and mind. It is the unity of science and art, where the precision of the grammar meets the expressiveness of the literacy, crafting the language of athletic excellence. Imagination of athletic statue as a result of literate and well-quantified approach to performance training. Practical Commentary. I believe that the analogy of language powerfully underscores the potential of a modern and positive approach to motor learning and strength training, particularly in sports and clinical contexts. This approach fosters a misleading sense of control over a process that cannot be fully comprehended through numerical analysis alone. It misses out on the artistic creativity – the crucial element that encourages thinking beyond conventional boundaries and truly understanding the depth and dynamism of human movement. As someone deeply committed to the scientific understanding of human movement, I find it disheartening when trainers and clinicians try to confine the complex phenomenon of movement to an overly reductionist perspective, devoid of the richness it inherently possesses. Recommender Reading: Whitehead M. Physical LiteracyThroughout the Lifecourse. Routledge (2010). Rudd JR et al. Physical Literacy - A Journey of Individual Enrichment: An Ecological Dynamics Rationale for Enhancing Performance and Physical Activity in All. Frontiers in Psychology (2020). Roetert EP et al. Physical Literacy: Why Should We Embrace This Construct? British Journal of Sports Medicine (2018). Enrich the Conversation. Respond to the ideas raised in this text by writing to me@pawelkrotki.com.

The decision to allow an athlete to return-to-sport (RTS) after an injury is complex and multifaceted. Clinicians must weigh various factors, such as the athlete's physical and psychological readiness, medical clearance and individual preferences. Understanding decision-making theories and sharing decisions among interdisciplinary staff of clinicians and coaches can help improve effectiveness and reproducibility of the RTS. Risk-based Definition. In sports medicine, a framework is a model that focuses on the most relevant aspects of successful and consistent health and performance outcomes. In a sense, this can be viewed as a simplification of the entire complicated scenario, encompassing all essential aspects required for recovery from a specific injury. One of the crucial components in constructing a relevant rehabilitation protocol is a risk-based decision-making approach. This approach is designed to aid decision-makers in determining when an athlete is prepared to initiate sport and/or team training outside the clinical environment. This kind of framework takes into account two primary components: (1) the risk assessment outcome and (2) the decision-maker's risk tolerance: Risk assessment outcome involves evaluating the potential risks associated with the athlete's RTS, for example the re-injury rate or potential chronic weaknesses and functional disorders. This evaluation should consider the athlete's healing progress, psychological readiness and most importantly: the balance between functional abilities and disabilities. Risk tolerance refers to the willingness to accept a certain level of risk, which could be influenced by factors, including economic, social and team conditions, athlete’s preferences and the potential consequences of returning to sport too early and/or physically unprepared. By comparing the results of the risk assessment to the decision-maker's risk tolerance, the framework based on the aforementioned model assists in guiding the decision-making process for returning to sports in a more structured manner. This can be viewed as a straightforward equation in which practitioners of rehabilitaiton establish idealised criteria and, by employing standardised testing methods, assess whether the objective outcomes align with these criteria. ■ Visual of the risk protection equation. □ Reduction of the prevalence of RTS risk should be based on standardised testing protocol based on available resources and information to give maximally objective reference point for clear and fast decision making within the group of collaborating doctors, physios, trainers and coaches. □ Standardisation testing outcomes creates the baseline, which should be enhanced by the current level of protocol completion, especially in means of performance training and tolerance to sport-specific expositions of high-intensity and unpredictable movement, which are often beyond the scope of objective measurements. Establishing a Baseline. Revisiting the most evident truths is a valuable practice, particularly in the rapidly evolving landscape of information and the development of innovative, technology-driven solutions in sports rehabilitation. One such truth to emphasize is that the primary focus of a successful RTS is to restore the pre-injury performance levels of an injured athlete. To achieve this, it is essential to establish a performance baseline for monitoring the progress of sports rehabilitation. However, creating an objective and replicable baseline is challenging because of the lack of precise guidelines and confusion regarding the timing, frequency and form of tests implementation. This picture can be furthermore distorted by the daily fluctuations in physiological and performance profiles. To illustrate concerns with the baseline setting, let’s point to the limb symmetry index (LSI). Although a 90% side-to-side difference within LSI threshold is commonly used, little scientific evidence supports this parameter and even achieving full symmetry does not necessarily indicate a level of fitness sufficient for safe participation in high-performance sport. Additionally, it is questionable whether the uninvolved side can be used as a benchmark when pre-injury data is not available. Consequently, defining a baseline measure for comparison remains a challenge. To overcome this problem it is popular to use the batteries of diverse tests that give a more direct insight into different qualities of biomechanics and values of dynamic motoric functions and imbalances. If a particular assessment reveals performance that falls short of an established standard – conceptualised both ideal and safe – it has the potential to point at specific motor function deficit. This deficit can be then targeted through corrective exercises as integral part of integrative methods of performance training. ■ Visual of the acknowledged aspects of comprehensive assessment that underlie the typical return-to-sport rationale and is documented throughout the rehabilitation process for an athlete, using our example of an anterior cruciate ligament reconstruction (ACLR) protocol. The optimal quantity of tests for assessing an athlete's condition may differ depending on the situation. Utilizing an inadequate number of tests could potentially compromise the clinician's ability to obtain a full understanding of the injured athlete's profile. Conversely, conducting an excessive number of tests might introduce greater error, i.e. paralysis by analysis and decreased performance resulting from fatigue or diminished motivation and consume additional resources, i.e. personnel, time, equipment. At present, there is no definitive guidance on the ideal combination or number of tests that would offer the most valuable insight into an athlete's preparedness for return to sport (RTS). Bounded Rationality. To understand how decisions may deviate from optimal outcomes due to limitations in information, time or processing capacity, medical and coaching staff members should be familiar with the theory of bounded rationality. It explains how humans take cognitive shortcuts and make decisions within the limitations imposed by the environment, abilities, information and the (overreaching) sporting goal. Simplification through heuristics can be helpful for clinicians to make efficient judgments without consuming too much time or processing capacity, especially when dealing with insufficient or overly complicated information. However, heuristics can also lead to deviations from rational decisions if not used carefully. Decision-making is often limited by factors of cognitive capacity, time constraints and incomplete information. Clinicians often face time pressures to make decisions about when athletes are ready to RTS and may lack access to all the relevant information about the athlete's holistic state of health and performance. Bounded rationality can help clinicians be more aware of their potential biases and can encourage them to seek out additional information or perspectives to make better decisions. It also highlights the importance of using evidence-based guidelines and standardised tests to help mitigate the impact of cognitive biases on decision-making. Shared Decision-Making. To address the challenges mentioned above, it is recommended to implement the ‘best practice of medicine’, which is shared decision-making. This approach involves partnership that should be settled between the athlete, clinicians, trainers and other stakeholders in the sports organisation and/or team. In this outlook, each stakeholder brings unique perspectives and concerns, making it essential to consider different viewpoints for a comprehensive decision of RTS. Shared decision-making ensures that decisions are well-informed, consider individual preferences and minimise discrepancies due to conflicting interests. Imagination of an athlete in action transcending limitations imposed by past injuries. Take-Home Message: Current research on RTS decision-making is limited and primarily focuses on biological and medical factors. Future research should explore decision-making theories, heuristics and biases in sports medicine practice. Additionally, as sports technology advances and provides an increasing amount of data, there is a need to develop tools, such as statistical models and artificial intelligence algorithms, to aid clinicians in processing information and making better decisions. The proposed risk-based framework aims to provide a systematic and objective approach for clinicians to improve the decision-making process in return to sport. By selecting appropriate tests, understanding decision-making theories, and employing shared decision-making, clinicians can enhance the quality of their decisions. Recommender Reading: Yung KK. A Framework for Clinicians to Improve the Decision-Making Process in Return to Sport. Sports Medicine OPEN (2022). King E at al. Biomechanical but Not Strength or Performance Measures Differentiate Male Athletes Who Experience ACL Reinjury on Return to Level 1 Sports. American Journal of Sports Medicine (2021). Wiggins AJ et al. Risk of Secondary Injury in Younger Athletes After Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-Analysis. American Journal of Sports Medicine (2016). Enrich the Conversation. Respond to the ideas raised in this text by writing to me@pawelkrotki.com.

The concept of 'desirable difficulty' in performance training is a vital approach for achieving long-lasting results. Current research uncovers the secret of mastering skill acquisition in sports and offers an understanding of the principles for effectively implementing difficulty in various training contexts. Challenging the Learner. Desirable difficulty refers to training conditions that stretch the learner's comfort zone and require more effort but ultimately lead to better retention and transfer of skills. This concept is based on the premise that easy, repetitive practice may not be the best way to achieve long-lasting learning outcomes. Desirable difficulty, in general, requires a coach to practice various skills in a mixed order, rather than focusing on each skill separately through blocked practice. This means that instead of practicing one skill repeatedly in a row, the trainee would alternate between different skills in a prescribed order or randomly. By switching between these skills during the practice session, players face a more challenging and engaging training experience, which ultimately leads to better retention and improved performance outcomes. ■ Visual of various session perspectives with different order strategies for skill training blocks. The schema provides simple examples of adjusting the session complexity based on skill difficulty levels, tailored to the individual performer's abilities to learn effectively from the challenges presented. □ The letters represent abstract tasks that make up the complete skill set of an athlete, with letter 'A' being the simplest and progressing in different difficulty characteristics of movement as the alphabet advances. Implementation Guidelines. The following principles have been identified as effective strategies to introduce desirable difficulty in training for high-performance and skill development: It is essential to note that the following rules are primarily applicable to skill training in sporting contexts and should not be directly replicated for the purpose of strength and power development in the gym environment, which – by nature – tends to be more repetitive, more predictable and much less varied as skill-oriented exercise. Variable Practice: It’s a technique that involves mixing different types of practice tasks or content, rather than focusing on one type of task or content at a time. Research shows that adding variability can lead to better retention and transfer of skills in both perceptual-motor and cognitive domains. Although it may initially seem counterintuitive and less efficient than blocked practice, variable practice has been consistently shown to benefit learning by mimicking real-world situations that require the integration and application of multiple skills. Distributed Pracite: Spacing practice sessions over time, rather than massing them together, leads to better long-term retention and performance. Incorporating delays between learning and retrieval attempts can enhance long-term retention by making the learner work harder to recall the information. The repetition of motoric skills serves a similar purpose to mnemonic techniques (flashcards), as it adds an additional layer of automation to the particular movement behaviour with each set of reps. Testing Blocks: Retrieving information from memory through testing or self-quizzing can promote long-term retention more effectively than passive review. Furthermore, spacing out practice sessions and revisiting material after a period of time can lead to a more robust understanding of the content. This effect encourages learners to actively engage with the movement tasks and reinforces the neural pathways required for recalling the information later on. Delayed Feedback: Immediate feedback during training can lead to dependency and hinder the development of self-assessment skills. Research suggests that delaying feedback and encouraging self-evaluation before providing feedback can help learners become more self-reliant and adaptive. This approach not only increases the difficulty of training but also fosters the development of self-evaluation and self-correction skills, which are essential for success in real-world situations. Training Under Pressure: In directly competitive sports, athletes often encounter high-pressure situations. Studies have shown that incorporating pressure into training can help learners become better prepared to perform under challenging conditions. By simulating sports-specific scenarios and incorporating elements of pressure, training programs can foster the development of coping strategies and build resilience in the face of adversity. ■ Visual representation of diverse microcycle perspectives, emphasizing the different stages of increasing different levels of training difficulty, based on the principles outlined in the article. Measure of Difficultness. Measuring of optimal level of difficulty can be a challenging task, as it requires finding the correct balance between the difficulty of a task and the learner's ability to benefit from it. Based on current scientific knowledge, a few key indicators can be used to assess the effectiveness of desirable difficulty in training: The rate of errors made by the learner during practice can be monitored. A moderate level of errors indicates that the task is challenging enough to stimulate learning without being too overwhelming. Measuring the retention and transfer of skills over time can provide insights into the long-term effectiveness of training strategies that incorporate desirable difficulty. Assessing the learner's level of engagement and motivation during training can also serve as an indicator of desirable difficulty, as more challenging tasks tend to keep learners engaged and motivated to improve. Imagination of athlete's struggle to comprehend sports-specific tasks in the learning process. Practical Commentary. Desirable difficulty in training and skill acquisition is an evidence-based approach that can lead to long-lasting learning outcomes. By incorporating principles such as testing, spacing, interleaving, delayed feedback, and training under pressure, learners can develop skills that are better retained and more easily transferred to contextual situations of sport. There is no one-size-fits-all approach to implementing desirably difficult training. The optimal balance of difficulty in practice conditions depends on the specific skills being learned, the context in which they are practiced, the instructors and the learners. It is important to gradually introduce challenging elements into the training, ensuring that learners experience a balance of success and difficulty. Implementing desirably difficult training requires careful consideration of the skills being learned and the specific needs of the learners, but when done correctly, it can result in significant improvements in performance and adaptability. Recommended Reading. Ericsson KA et al. The Cambridge Handbook of Expertise and Expert Performance. Cambridge: Cambridge University Press (2006). Farrow D et al. Developing Sport Expertise: Researchers and Coaches Put Theory into Practice (2nd ed.). Routledge (2013). Magill RA et al. Motor Learning and Control: Concepts and Applications. McGraw-Hill Education (2016). Enrich the Conversation. Respond to the ideas raised in this text by writing to me@pawelkrotki.com.

The quest for knowledge in natural sciences often leads researchers and practitioners to grapple with the delicate balance between simplicity and complexity. In this series of articles I delve into the various approaches used to study complex phenomena, shedding light on the advantages and limitations of (1) simple–reductionist methods versus (2) more complex–holistic ones. I also explore the concept of uncertainty, a challenge inherent to understanding complex systems and discuss the pitfalls of 'physics envy' – the desire to achieve the precision and mathematical rigor of physics in other scientific fields than those which solely rely on the language of mathematics. Together with imagination, I will try to find analogies from the world of sports and health sciences, through which it will be easier to understand the issues discussed. Drawing from the practical insights, I will also do my best to offer guidance for navigating the complications found, among others in behavioural and exercise research, ultimately emphasizing the importance of striking the right balance: embracing diverse perspectives and acknowledging limitations and uncertainties in the pursuit of understanding. The Dichotomy. "Everything should be made as simple as possible, but not simpler” – Albert Einstein. The essence of comprehensive thinking depends much on our cognitive abilities. One of them is seeing the world without too rigid fixations on contrasts and tensions between the seemingly opposing views of simple vs complex. It emphasizes the need to simplify our understanding, but in a quite flexible way reaching far beyond oversimplification where important details and nuances are lost. Sounds like a paradox? Absolutely! ■ Visual of the ranges of (1) simple and (2) complex approaches used to understand the principles that govern the world around us. Developing a well-rounded understanding in fields such as human behaviour and sports science often requires embracing a complex knowledge and a 'blend' of interdisciplinary methods, diverse perspectives and a balance between reductionist insights and holistic understanding. Striking the Balance. Focusing only on breaking things down into smaller parts might cause us to miss important connections and how everything works together. On the other hand, if we make our explanations too complex, they can become difficult to understand and apply in real-life situations. Both approaches have their merits and drawbacks, and the choice between them often depends on the specific question, available resources, and the desired level of understanding. To exemplify this topic, let’s consider sports rehabilitation: Many clinical guidelines are based on the use of simple and injury-specific exercises that are easy to control and measure. They express a reductionist approach in which ‘the whole’ is broken down into smaller parts, which are a critical aspect of functional improvement. However, if we want the process to become more individualized and sports-specific, it may be worth conducting sporting drills and skill training at the right time of the protocol's timeline. Example of Strength. This type of formative reasoning is also found in many other areas of fitness and health, one of such is strength training: Simple approach might involve a few basic exercises, i.e. squat, deadlift and bench press and a straightforward progression scheme, such as linear periodization. The coach would set a target for the number of set–reps and weight lifted, gradually increasing the load over time. This approach is easy to understand and implement, making it suitable for beginners, injured patients or those with limited resources. However, it may not be optimal for advanced athletes or those with specific needs, as it does not take into account individual differences or different factors that can influence strength development. Complex approach would involve a more comprehensive assessment of the athlete's needs and also individual strengths and weaknesses. This approach might include a detailed biomechanical analysis, movement screening and performance testing to inform exercise selection and program design. The training program can be periodized, with different phases focusing on various aspects of strength development, such as hypertrophy, maximal strength and power training. Advanced techniques based on motor learning principles, accumulation methods and conditioning could be incorporated to optimize progress and minimize the risk of injury. This approach requires greater resources and expertise, making it more suitable for advanced athletes or those with specific performance goals. Imagination of wave as an iconic example of entity classified as complex phenomenon. Practical Commentary. In building our understanding, it can be helpful to start with a (1) simple–reductionist approach to grasp the fundamental concepts and components of a subject. Once a solid foundation is established, we can then transition to more (2) complex–holistic approaches to explore the interactions, context-dependent factors and emergent properties that are often present in intricate phenomena. This progressive learning strategy allows for a deeper and more comprehensive understanding of the subject matter, based on current scientific knowledge, but with consideration that in case of beginner physios and coaches it shouldn’t be learned the other way round. The next part of this series will cover the pros and cons of both ways of gaining understanding, unveiling common biases perpetrated by practitioners in the fields of health- and sport-related subjects. Recommended Reading. Mitchell M. Complexity: A Guided Tour. Oxford University Press (2009). Ladyman J et al. What is a Complex System? European Journal for Philosophy of Science (2013). Plsek PE et al. Complexity Science: The Challenge of Complexity in Health Care. British Medical Journal (2001). Enrich the Conversation. Respond to the ideas raised in this text by writing to me@pawelkrotki.com.

"Sports medicine is about getting people back to the sport they love, keeping them in the sport they love and doing it the right way” – Dr. James R. Andrews. Sports medicine is designed to help athletes recover from injuries and return to their sports safely and effectively. Its aim is to improve an athlete's recovery process, develop injury prevention strategies and ensure athletes can maintain their performance levels post-injury. In the context of anterior cruciate ligament reconstruction (ACLR) this includes advancements in surgical techniques, rehabilitation protocols and return-to-play criteria. Even so, taking all this into account, meeting all the recovery criteria does not guarantee that an athlete will not suffer a reinjury. It does, however, significantly reduce the risk. Level I Sports. It’s worth to note that different reinjury rates numbers will change based on the athletic population being studied. They can additionally differ depending on factors such as type of sport, the individual physical condition and rehabilitation protocols. On average, reinjury rates for competing athletes range between 5% and 20% after returning to their respective sports. It is difficult to pinpoint a specific sport with the highest reinjury rate after ACLR. Yet, sports with a higher overall risk of ACL injuries and reinjuries, called 'level one sports', are typically those that involve frequent cutting, pivoting and sudden changes of direction as well as high defensive and offensive impact forces during the game. These sports often include: football, basketball, skiing, handball and volleyball. Other factors. Situation is worse in case of young players, where almost 25% of individuals who are of a younger age (<25 yo) and return to a level I sport will either reinjure the reconstructed ACL or injure the opposite side. Factors contributing to this include their ongoing physical development, a relatively early sports specialisation and unrealistic drive for return to play quickly. Gender is another factor that can contribute to higher reinjury rates in athletes after ACLR. Female athletes have been found to be at a higher risk of reinjury after ACLR compared to male athletes, likely due to anatomical, hormonal and neuromuscular factors. Moreover, females have a greater proportion of second injury to the contralateral (opposite) ACL (62%), whereas second reinjury in case of males seems to occur more often to the reconstructed ACL graft (75%). Outmost fact to recall is the scale of emotional drama experienced by athletes after the knee damage. Regardless of first or future injuries, the threat that 15% of all athletes dealing with ACL-related injuries will permanently leave the sport they are passionate about, is still present. Visual of the theoretical consideration of op-limb compared to non-op and pre-op performance levels suited for the timeline of traditional rehabilitation model showing the abstract inconsistency (gap) of the sport-specific needs (expectations) compared to the reported outcomes (reality). It's worth noting that capturing the 'gap' may reach beyond the quantitative metrics obtained conventionally in the clinical and gym settings, suggesting that other factors regarding neuromuscular and skill-specific conditioning, i.e. horizontal forces exposition, lack of motor control on the neuromuscular level and persistent prediction errors due to athlete's emotional state may also contribute to the whole picture of RTS readiness. Prevention Strategies. There is an urgent need to identify practical and evidence-based solutions. The suspected 'gap' between the anticipated outcomes of the rehabilitation and the actual effects of methods used in standard sports medicine creates a challange where reason should work together with innovation. To enhance the current state-of-the-art in professional rehabilitation and reduce the still significant hazard of subsequent injuries following ACLR, medical professionals and sports staff should consider further advancements in reconstruction techniques and rehabilitation protocols along with an integrative cooperation under a unified framework of return-to-play process. In particular, these consist of: Asking the right questions about what constitutes the 'gap' of performance. Keeping an injured athlete in rehab training until <9 mo after surgery, despite the satisfying outcomes being documented and correcting the most relevant deficits, apparently in the matter of motor control. Integrating of conventional strength exercises with neuromuscular and sport-specific skill training within collaborative framework with reference to physician, physio and S&C coach responsibilities. Implementing the injury prevention programs, which might be crucial in collision sports, to prepare for potentially harmful situations of running, falling, assaulting and defending (worst case scenarios). Finding a replicable consensus in the medical community regarding objective criteria that is required before athletes are released to full sports participation after ACLR, especially concerning the utilisation of clinical assessment, testing batteries, dynamometrics and available normative data. Imagination an athlete's emotional collapse as they confront another injury in their career. Take-Home Message. Adequate maintenance of performance levels after ACLR aimed at fulfilling the specific requirements of a given sport may contribute to the significant reduction of future reinjury rates in athletes. Medical and sporting staff should seek further advancements in surgical techniques and return-to-play criteria, apart from the apparent need of better cooperation within the clinical environments. Much work remains to bridge the still apparent inconsistency between theory of conventional rehabilitation used worldwide and the reality of still apparent reinjury rates in the athletic population, especially in terms of highly-vulnerable athletic youth. This article is published for informational purposes only. It is not intended to be a substitute for professional medical advice and should not be relied on as health or personal advice. Further Reading. Barber-Westin et al. One in 5 Athletes Sustain Reinjury Upon Return to High-Risk Sports After ACL Reconstruction: A Systematic Review in 1239 Athletes Younger Than 20 Years. Sports Health (2020). Shelbourne KD et al. Incidence of Subsequent Injury to Either Knee Within 5 Years After Anterior Cruciate Ligament Reconstruction with Patellar Tendon Autograft. American Journal of Sports Medicine (2009). Paterno MV et al. Incidence of Second ACL Injuries 2 Years After Primary ACL Reconstruction and Return to Sport. American Journal of Sports Medicine (2014).

“Scientific knowledge, like language, is intrinsically the common property of a group or else nothing at all. To understand it we shall need to know the special characteristics of the groups that create and use it." – Thomas Kuhn. Although Kuhn's focus was on scientific paradigms and how they influence the way scientists view the world, the idea can be easily translated into the concept of integrative frameworks used in practice of sports rehabilitation and medicine. The way practitioners of science (including physios and coaches) create their protocols, is thus greatly based on the scientific structures that help to organize and guide practitioners in their approach to patient care, fostering collaboration and facilitating the application and innovation of evidence-based practices. Despite the fact that Kuhn's theory dates back to the 1962, when his most marvellous book on theory of science, titled: ‘The Structure of Scientific Revolutions’, was published, we see clear parallels that are still very much up-to-date. What is Framework? In sports medicine and rehabilitation we deal with complex stuff. To Simplify the complexity we need more structured and more integrative approach. To capture the set of principles that helps us understand, analyze, and address the multifaceted aspects of the subject of an injured athlete, we need a framework. Visual of sports rehab framework example that provides a foundation for organizing knowledge, guiding training and testing and facilitating communication among specialists managing the specific type of injury. Despite the useful simplification of any schema obtained that way, medical and coaching staff gains the division into individual phases of rehabilitation, common language, guidance in shared decision-making, assessment methods of the process and foundation for further research that encourages the innovation development. What it Offers? Comprehensive recovery: An integrated approach addresses all aspects of the athlete's recovery, including physical, psychological and biomechanical factors. This comprehensive approach ensures that the athlete receives a well-rounded rehabilitation program that takes into account their specific needs, promoting a more effective and efficient recovery process. Interdisciplinary collaboration: A framework that integrates various treatments and exercise modalities encourages collaboration among healthcare professionals, such as physicians, physical therapists, strength and conditioning coaches and sports psychologists. This interdisciplinary teamwork allows for better communication, more effective treatment planning and a coordinated approach to care, ultimately resulting in better outcomes for the athlete. Injury prevention: By addressing not only the immediate injury but also potential contributing factors, such as muscle imbalances, poor movement patterns or insufficient training, an integrated approach helps prevent future injuries. This proactive focus on injury prevention is critical for athletes aiming to maintain their competitive edge and avoid setbacks in their performance. Performance enhancement: An integrated framework of treatments and exercise not only focuses on recovery from the injury or surgery but also aims to improve the athlete's overall performance. By incorporating strength and conditioning, sport-specific training and motor learning principles, the rehabilitation process can help athletes return to their sport at a higher level of performance than before their injury. Psychological support: Injuries and surgeries can have significant psychological impacts on athletes, affecting their motivation, confidence and self-efficacy. An integrated approach that includes psychological support, such as mental skills training and counseling, can help athletes cope with the emotional challenges of rehabilitation, enhancing their overall recovery and return to sport. Individualized care: A framework that integrates various treatments and exercise modalities allows for greater customization of the rehabilitation plan, ensuring that each athlete's unique needs and goals are addressed. This individualized approach results in more effective and targeted interventions, ultimately leading to better outcomes for the athlete. Imagination of one of the most recognized philosophers of science Thomas Kuhn in the football pitch. Practical Commentary. Creating a framework of integrated treatments and exercise in sports rehabilitation is crucial for ensuring a comprehensive, interdisciplinary, and individualized approach to care. This approach not only promotes optimal recovery from injury or surgery but also helps athletes prevent future injuries, enhance their performance, and address the psychological challenges associated with rehabilitation. This article is published for informational purposes only. It is not intended to be a substitute for professional medical advice and should not be relied on as health or personal advice. Further Reading. Kuhn T. The Structure of Scientific Revolutions. University of Chicago Press (1962). Meadows DH. Thinking in Systems: A Primer. Chelsea Green Publishing (2008). Yung KK. A Framework for Clinicians to Improve the Decision-Making Process in Return to Sport. Sports Medicine OPEN (2022).

“The secret of being a bore is to tell everything” – Voltaire. The idea that overusing certain expressions can make it tiresome and uninteresting exactly fits the word ‘natural’ as being one the most misused words, specifically among the self-help and wellness industry. That’s the pity, because the natural perspective, from the very beginning of the astonishing history of all natural sciences, was (and indeed still is) the main subject of research that seeks fundamental understanding of the physical (non-living) and living (biology, human and health–performance) world around us. Visual of natural sciences with simplified division of physical and life sciences. All sciences tend to point out principles, called laws of nature, being more accurate descriptions of the natural phenomena found in the surrounding world. Mc Natural. Frequent mindless repetitions of the word ‘natural’ in speech, writing and media impacts the original sense or novelty of the still very mysterious idea about the Nature itself. This is how a cliché is formulated becoming dull, predictable and trite, failing to convey a fresh or insightful perspective on a subject, being ultimately a betrayal of a lack of original thought, something we might even call a Mc Nature. The popularity of the term stems from the general perception that things labeled as ‘natural’ are inherently better, healthier or safer than their synthetic or artificial counterparts. This perception, however, isn't always accurate, as not all natural substances or products are inherently safe or beneficial and not all synthetic substances are harmful or inferior. Some reasons why 'natural' has become a banality include: Consumer appeal: many companies capitalize on the positive connotations associated with the term 'natural' to promote their products, regardless of whether the product is genuinely natural or has any real benefits over alternatives. Greenwashing: products labeled as "natural" may in some cases contain synthetic or artificial ingredients, or the natural ingredients might be present in insignificant amounts. Oversimplification: the notion that 'natural' equals 'better' or "safer' is a common bias based on oversimplicity. While some natural products can have advantages over synthetic alternatives, this is not always the case. Excessive use of the these practices causes the state in which the term 'natural' is so diluted. Nature Works. Of course, we find a plenty of natural remedies used in modern medicine that were derived straight from nature, to list just a few: aspirin (willow tree), artemisinin (sweet wormwood), morphine (opium poppy), digitalis (foxglove plant) or psyllium (plantago ovata). Pharmacology enhances their efficiency by synthesising their chemical structure, thus minimising potential side and placebo effects and pointing (with evidence) the specific mechanism of positive influence on the biological level of the living organism. Sports medicine follows that strategy of maximizing the precision effect on body's functioning and when it's indicated by proven outcomes, chooses the natural solutions. Fair example is the use of natural tissue autografts in ligament reconstruction surgeries (from the patient's own body) rather than synthetic ones made from artificial materials, such as carbon fibres, due to their greater durability, long-term efficacy and safety. Important phenomenon to mention is physical exercise, being one of the finest examples of natural intervention – a key ingredient of all preventative care – causing a cascade of health-related pharmacological effects that cannot be replaced by any single manufactured pill. It strengthens the person's body–and–mind, acts as shield agains multitude of diseases and may be one of the crucial factors of person's longevity. Apparently, the attitude of modern medicine to natural solutions seems to be very ethical and healthy. Moreover, ff we acknowledge the deep scientific understanding of the (again) natural immune response of humans and the molecular biology of the SARS-CoV-2 virus that shaped the rapid invention of the vaccine that saved lives, saying that vaccines – still being a topic full of controversies – are something absolutely opposite to the ‘natural’ is a fool's lie. Matter of Perception. At this stage, we directly see that much depends on how the word 'nature' is perceived, understood and defined. But "vaccines don't grow on trees, they are artificially obtained" – being one of the main cognitive and emotional conflicts of the discussed rationale, a source of misunderstanding and the lack of fundamental knowledge of the principles governing the complex phenomenon of health. There are numerous instances where chemical drugs have proven more effective than natural alternatives in treating various medical conditions, e.g. antiviral medications, antibiotics, antidepressants, chemotherapy and insulin, all offering more targeted and potent treatment options, despite being 'synthetic' in the common sense. Therefore advising that in the context of a serious disease 'natural' in means of non-synthetic is explicitly better, thus overriding the more targeted medicinal cure is something potentially unethical and harmful. Imagination of the natural scientist seeking fundamental understanding of the Nature. Practical Commentary. It's clinical reasoning it's important to regularly remind ourselves of what natural intervention really is and not follow blindly the overused perspective of the term 'natural' used in the modern society. The efficacy of a treatment should not solely be determined by whether it is natural or synthetic, but rather by its proven effectiveness in addressing a particular medical condition. Oversimplification based on the purely natural perspective of treatments can be harmful to health. This article is published for informational purposes only. It is not intended to be a substitute for professional medical advice and should not be relied on as health or personal advice. Further Reading. Farnsworth NR et al. The Conservation of Medicinal Plants. Chapter: Global Importance of Medicinal Plants. Cambridge University Press (1991). Ernst E et al. The Desktop Guide to Complementary and Alternative Medicine: An Evidence-Based Approach. Journal of the Royal Society of Medicine (2000). West RV et al. Graft Selection in Anterior cruciate Ligament Reconstruction. Journal of the American Academy of Orthopaedic Surgeons (2005).

The science of complex phenomena is often referred to as complexity science or the study of complex systems, one of which (in a significant part) is science applied in sports and exercise health. It aims to understand the principles that govern the behaviour of complex phenomena like human movement, to predict their behaviour, and to design interventions, programs or protocols that can effectively manage and/or control them. It is a multidisciplinary field that seeks to understand the behaviour and properties of systems with many interacting components, known as agents, which can give rise to emergent, non-linear, and self-organizing behaviours. These systems are typically characterized by their unpredictability, adaptability, and interconnectedness. Complex systems can be found across various domains, including biology, ecology, economics, social sciences, and even sports technology. Some examples include ecosystems, human brain, sports betting, team-club interactions and the internet. Researchers in complexity science use tools from mathematics, computer science, physics, and other disciplines to model, simulate, and analyze the behaviour of particular phenomena dynamics. Key concepts in complexity science include: 1. Emergence: The idea that the behaviour of a complex system can arise from the interaction of its components, resulting in patterns or properties that are not apparent in the individual components themselves. 2. Adaptation: The capacity of a complex system to change its behaviour or structure in response to changes in its environment or internal dynamics. 3. Self-organization: The ability of a complex system to spontaneously develop order or structure without external guidance or control. 4. Nonlinearity: The presence of feedback loops and interactions within a complex system that lead to unpredictable and disproportionate responses to changes in input. 5. Networks: The study of the structure and dynamics of interconnected nodes or agents within a complex system. Complexity in Sports Science. Visual – From cell to club scale interactions with the performer (athlete) and the surrounding environments. Based on Pol R et al. Training or Synergizing? Complex Systems Principles Change the Understanding of Sport Proces. Sports Medicine OPEN (2020). Science applied in sports, exercise and fitness might not always be explicitly framed as studies of complex systems, yet it involves the investigation of complex–interconnected factors that influence human performance, health and well-being. These components include physiological, biomechanical, psychological, and nutritional factors, among others. In sports and exercise science, researchers often examine the interactions between these components in order to understand how they collectively influence athletic performance, injury prevention, and overall health. The human body itself can be seen as a complex system, with numerous interconnected subsystems (i.e. musculoskeletal, cardiovascular and nervous systems) that work together to enable physical activity and adapt to various training stimuli. Moreover, sports and exercise science also considers external factors, such as environmental conditions, coaching strategies, and social dynamics, which can further add to the complexity of the systems being studied. The multidisciplinary nature of human movement behaviour and sporting performance, which draws upon fields such as physiology, biomechanics, psychology, and nutrition, reflects the complexity of the systems being investigated. Imagination of an athlete struggling with complexities of his body and the surrounding environment. Practical Commentary. From the perspective of a practitioner who avoid overcomplexity like a plague and perceive it as a an obstacle in building coherent understanding (of complex phenomena) in the fields of sports coaching and clinical reasoning, I acknowledge the importance of synergizing factors that are non-linear in means of motor learning, contextually functional or unfunctional and based on performer–environment and team–club interactions, thus being much more holistic. At the same time, I do not give up the linear, quantitative and useful reductionist approaches, while building the integrative model even more solid w/o extreme claims that the only (true) way is the way of constant uncertainty (too complex) or the way of cartesian reductionism (too simple). Follow to the next article related to that topic: Simple vs Complex. Further Reading. Pol R et al. Training or Synergizing? Complex Systems Principles Change the Understanding of Sport Proces. Sports Medicine OPEN (2020). Robertson S et al. Bounded Rationality Revisited: Making Sense of Complexity in Applied Sport Science. SportRxiv (2019). Salmon PM et al. Complexity in the Beautiful Game: Implications for Football Research and Practice. Science and Medicine in Football (2019).