Biochemistry in Sports Performance: Unlocking the Molecular Secrets to Enhanced Athletic Potential

The use of biochemical aids to enhance athletic performance has a long history. In our current sporting culture we attempt to divide these between the accepted legal ‘ergogenic aids’ and the unacceptable performance-enhancing ‘drugs’. It is unclear whether this distinction would have been made 2000 years ago when Pliny the Elder reported the effects of Horsetail juice on performance. Interestingly, the sporting ergogenic effects of horsetail haven’t passed the test of time. In the middle ages its astringency, due to its high silica content, made it ideal for scouring pewter and wooden kitchen utensils. The juice's current ergogenic properties are more refined, its main use being in bath and shower products where a ‘natural conditioning effect’ is required. Perhaps more controversially, hidden amongst his 600 books, Claudius Galen, the 2nd century Greek physician to the gladiators, mentioned the positive effects of eating herbs, mushrooms and testicles. Galen believed that the right testicle was hotter and purer than the left, though whether this led to differential performance-enhancing effects was not rigorously tested. We shouldn't think that modern people are unusual in being obsessed with winning at all costs. Philostratos's (200 AD) view of the Ancient Greeks was that “They made war training for sport and sport training for war.” He was less impressed with his generation of sportsmen who “spent too much time eating, drinking and fornicating instead of actually training”. This was reflected in their poor choice of ergogenic aids. Although the ancient Spartan athletes trained on a meat-full diet of bulls, oxen, goats and deer, athletes of his generation ate white bread, poppy seeds, fish and pork [1]. They treated sports as “more of a hobby than a way of life”. Grumpy old men are clearly not a modern phenomenon! Clearly, if not actually preparing for war, … The use of biochemical aids to enhance athletic performance has a long history. In our current sporting culture we attempt to divide these between the accepted legal ‘ergogenic aids’ and the unacceptable performance-enhancing ‘drugs’. It is unclear whether this distinction would have been made 2000 years ago when Pliny the Elder reported the effects of Horsetail juice on performance. Interestingly, the sporting ergogenic effects of horsetail haven’t passed the test of time. In the middle ages its astringency, due to its high silica content, made it ideal for scouring pewter and wooden kitchen utensils. The juice's current ergogenic properties are more refined, its main use being in bath and shower products where a ‘natural conditioning effect’ is required. Perhaps more controversially, hidden amongst his 600 books, Claudius Galen, the 2nd century Greek physician to the gladiators, mentioned the positive effects of eating herbs, mushrooms and testicles. Galen believed that the right testicle was hotter and purer than the left, though whether this led to differential performance-enhancing effects was not rigorously tested. We shouldn't think that modern people are unusual in being obsessed with winning at all costs. Philostratos's (200 AD) view of the Ancient Greeks was that “They made war training for sport and sport training for war.” He was less impressed with his generation of sportsmen who “spent too much time eating, drinking and fornicating instead of actually training”. This was reflected in their poor choice of ergogenic aids. Although the ancient Spartan athletes trained on a meat-full diet of bulls, oxen, goats and deer, athletes of his generation ate white bread, poppy seeds, fish and pork [1]. They treated sports as “more of a hobby than a way of life”. Grumpy old men are clearly not a modern phenomenon! Clearly, if not actually preparing for war, …

Background: The burgeoning field of nutrigenomics offers a promising avenue for enhancing athletic performance through personalized nutrition plans tailored to an individual's genetic makeup. This study delves into the intricate dynamics between gene-diet interactions and their implications for athletes' performance, recovery rate, and endurance levels, thus contributing to the growing discourse on personalized sports nutrition and training regimens. Objective: The primary objective of this study was to investigate the impact of gene-diet interactions on sports performance, with a specific focus on understanding how these interactions influence athletes' recovery rates and endurance levels. The study aimed to provide empirical evidence to support the development of personalized nutrition and training strategies in the realm of sports. Methods: Utilizing a quantitative research design, this investigation analyzed data from 400 athletes, drawing on secondary sources, including the World Bank's extensive databases. Statistical analyses were conducted using the Statistical Package for the Social Sciences (SPSS) Version 25, encompassing descriptive statistics, Pearson correlation analysis, regression analysis, and factor analysis through Principal Component Analysis. This comprehensive methodological approach aimed to unravel the complex relationships between genetic variations, dietary patterns, and athletic performance metrics. Results: Descriptive statistics revealed a wide range of performance scores (50.57 - 99.60), recovery rates (1.02 - 9.99), and endurance levels (1.00 - 9.93), indicating significant variability among athletes. Correlation analysis demonstrated a modest but significant relationship between recovery rate and performance score (r = .140, p < .05), while regression analysis showed minimal explanatory power of gene variation and diet type on performance scores (R Square = .012). Factor analysis identified a latent factor predominantly influenced by recovery rate, suggesting an underlying trait affecting various aspects of athletic performance. Conclusion: This study underscores the complex and multifaceted nature of gene-diet interactions in influencing sports performance. The findings advocate for a more nuanced, personalized approach to nutrition and training, emphasizing the need for further research to explore a broader spectrum of genetic and dietary factors. The potential of nutrigenomics in sports underscores the importance of individualized dietary plans in optimizing athletic performance and recovery.

Physiological Aspects of Sport Training and Performance, Second Edition, updates and expands on the popular first edition, providing an in-depth discussion of physiological adaptation to exercise. Students will learn the importance of an evidence-based approach in prescribing exercise, while sports medicine professionals and health care providers will appreciate using the text as a primary reference on conditioning and performance of athletes. A range of topics are covered, including environmental influences on performance, hydration status, sport nutrition, sport supplements, and performance-enhancing drugs. The book is focused on physiological adaptation to exercise with a goal of providing practical applications to facilitate exercise prescriptions for a variety of athletes. Physiological Aspects of Sport Training and Performance, Second Edition, is organized into five parts. The first part examines physiological adaptation and the effects of various modes of training on biochemical, hormonal, muscular, cardiovascular, neural, and immunological adaptations. The second part covers principles of exercise training and prescription. The third part discusses nutrition, hydration status, sport supplementation, and performance-enhancing drugs. The fourth part focuses on environmental factors and their influence on sport performance. The fifth and final part is focused on how certain medical and health conditions influence sport performance. Updates in this second edition focus on cutting-edge knowledge in sport science and sports medicine, including the latest information on physiological adaptations to exercise; current trends for training for power, speed, and agility; eye-opening discussions on sport supplementation and performance-enhancing drugs; data on training with medical conditions such as diabetes and exercise-induced bronchospasm; and groundbreaking information on training in heat and cold and at altitude. In addition, new chapters offer a practical approach to the yearly training program and sudden death in sport. This online edition of the text includes access to videos of over 40 drills being performed in their entirety, including a dynamic warm-up routine video features 10 warm-up exercises.

Genes control biological processes such as muscle, cartilage and bone formation, muscle energy production and metabolism (mitochondriogenesis, lactic acid removal), blood and tissue oxygenation (erythropoiesis, angiogenesis, vasodilatation), all essential in sport and athletic performance. DNA sequence variations in such genes confer genetic advantages that can be exploited, or genetic 'barriers' that could be overcome to achieve optimal athletic performance. Predictive Genomic DNA Profiling for athletic performance reveals genetic variations that may be associated with better suitability for endurance, strength and speed sports, vulnerability to sports-related injuries and individualized nutritional requirements. Knowledge of genetic 'suitability' in respect to endurance capacity or strength and speed would lead to appropriate sport and athletic activity selection. Knowledge of genetic advantages and barriers would 'direct' an individualized training program, nutritional plan and nutritional supplementation to achieving optimal performance, overcoming 'barriers' that results from intense exercise and pressure under competition with minimum waste of time and energy and avoidance of health risks (hypertension, cardiovascular disease, inflammation, and musculoskeletal injuries) related to exercise, training and competition. Predictive Genomics DNA profiling for Athletics and Sports performance is developing into a tool for athletic activity and sport selection and for the formulation of individualized and personalized training and nutritional programs to optimize health and performance for the athlete. Human DNA sequences are patentable in some countries, while in others DNA testing methodologies [unless proprietary], are non patentable. On the other hand, gene and variant selection, genotype interpretation and the risk and suitability assigning algorithms based on the specific Genomic variants used are amenable to patent protection.

An athlete's dietary and supplement strategies can provide a valuable contribution to overall sport performance. Personalized nutrition for athletes and fitness enthusiasts aims to optimize nutrition status, body composition, and exercise performance by tailoring dietary recommendations to an individual's genetic profile. Sport dietitians and nutritionists have long been modifying the one-size-fits-all general population dietary guidelines in order to accommodate the needs of athletes. In general, high-performance sport requires the addition of carbohydrates to fuel training and higher protein intakes to repair muscle. However, generic recommendations still remain with regard to micronutrients, food intolerances, bone health, risk of muscle damage, and various other performance-related nutritional factors that deserve consideration. Genetic variation is known to affect absorption, metabolism, uptake, utilization, and excretion of nutrients and food bioactives, which can alter the activity of metabolic pathways. Nutrigenomics and nutrigenetics are experimental approaches that use genomic information and genetic testing technologies to examine the role of individual genetic differences in modifying an athlete's response to nutrients or substances in foods and supplements. With the exception of caffeine, there have been few randomized, controlled trials examining the effects of genetic variation on performance in response to dietary interventions or ergogenic aids. However, there is a growing foundation of research linking gene–diet interactions on biomarkers of health and nutritional status. This means that reaching specific targets for an athlete's nutritional status to optimize health and body composition will in turn beneficially affect exercise and sport performance. These concepts and their actions form the basis from which the field of sport nutrigenomics continues to develop. Here we review the current science that associates genetic modifiers with foods, nutrients and ergogenic aids, and their impact on athletic performance.

Ergogenic supplements are defined as substances that contribute to or support the doing or production of a job. These supplements are used for many purposes such as increasing the performance of athletes, accelerating recovery in athletes, improving capacity, and reducing and preventing muscle injuries and muscle fatigue. Ergogenic supplements, which are of great interest to athletes and trainers, are classified as nutritional aids, pharmacological aids, psychological aids, mechanical and biomechanical aids, and physiological aids. Among these supplements, they are the most actively used nutritional aids and attract attention in the market as muscle-building nutritional supplements, weight-reducing nutritional supplements, performance-enhancing nutritional supplements, and general health-promoting nutritional supplements. Protein and amino acids provide benefits in long-term or short-term explosive power activities. Fats are used as the main fuel in long-term aerobic exercises. In addition, caffeine, ginseng, antioxidants, and coenzyme Q10 also serve as ergogenic nutritional supplements. It has been reported in studies that minerals such as B, C and E vitamins, chromium, magnesium, iron, and zinc affect sports performance in a good way. In case of deficiency of the aforementioned vitamins and minerals in athletes, many negativities occur. In this study, the use of ergogenic nutritional supplements by athletes before, during, and after training was compiled using the current literature on the types of these supplements.

Position of the New Zealand Dietetic Association (Inc): Nutrition for exercise and sport in New Zealand

ABSTRACTIn competitive and elite sports, mental health and athletic performance cannot be considered separately. Mental disorders in sports are bidirectionally associated with reduced athletic performance. A decline in performance, both within and outside of sport, can be a sign of mental disorder. Additionally, poor athletic performance is a potential risk factor for mental disorders in athletes. The central role sports psychiatrists play in the mental health of athletes is well‐established. However, their role in athletic performance is less well‐described and more controversial, perhaps due to a perception that performance is purely a secondary outcome of good mental health. This paper discusses the role that sports psychiatrists can play in athletic performance within competitive and elite sports. Performance can be distinguished into three key focus areas for sports psychiatrists: (i) performance restoration, (ii) performance maintenance, and (iii) performance enhancement. These should be considered throughout the continuum of mental health care, from prevention, treatment, to ongoing care for mental disorders. When reduced performance is due to a mental disorder, psychiatric treatment should purposefully aim to restore functioning and performance as part of management. Maintenance of performance is, similarly, an important element of the prevention, psychiatric treatment, and ongoing care of mental disorders. Holistic sports psychiatrists may also choose to aim for athletic performance enhancement beyond the context of mental health symptoms and disorders, to help athletes flourish and achieve their goals.

Objective: Traditionally, perfectionism has been regarded as a commendable trait in the realm of sports and exercise. However, recent research has uncovered a paradoxical aspect of perfectionism in these domains. This umbrella review seeks to offer a comprehensive overview of the intricate role that perfectionism plays in sport and exercise performance. Method : As an umbrella review, we systematically explored three widely used scientific databases-PubMed, Scopus, and ISI-to identify relevant systematic reviewes and meta-analyses investigating the relationship between perfectionism and sports performance. Results: After careful evaluation, eight studies met our inclusion criteria and were included in the study. These eight eligible studies comprised five systematic reviews and three systematic review and meta-analysis publications. These publications have explored the correlation between perfectionism and sports performance in teenager and adult populations, as well as professional and amateur athletes. Most of the original articles included in these studies had a cross-sectional design and some of them were longitudinal research. All reviewed articles reported a significant correlation between perfectionism and sports performance, regardless of gender and age. In general, the main consensus of these studies is a moderate to high positive correlation between perfectionistic strivings and sports performance, as well as a moderate to high negative correlation between perfectionistic concerns and sports performance. Conclusion: In summary, perfectionism exhibits both positive and negative effects on athlete outcomes. Maladaptive perfectionism is linked to adverse consequences, while adaptive perfectionism can yield positive effects. Promisingly, psychological interventions such as mindfulness-based approaches and ACT-based interventions show potential in reducing perfectionism and enhancing athlete outcomes. Future research should delve deeper into the intricate relationship between perfectionism and athlete performance and continue to devise interventions that counteract the detrimental effects of perfectionistic tendencies.

In the past few years, much research has been conducted on edible mushrooms, among which Pleurotus ostreatus (PO)—also known as oyster mushrooms—has received attention due to its many health and medicinal benefits. Some research has shown that PO and its active compounds, such as lectins, polysaccharides, primarily β‐glucans, phenols, polyphenols, terpenoids, ergosterols, and glycoproteins, are strong immune system modulators, have anti‐inflammatory properties, and have potentially positive effects on the cardiovascular system and athletic performance. In this narrative review, an extensive search (academic databases from inception to April 25, 2024) was conducted in the scientific literature, and various aspects of PO and its effects on health and athletic performance were investigated. This narrative review article thereby demonstrates the potential benefits of PO for improving the overall baseline health and concomitant athletic sports performance, recovery, and cardiovascular system function. In addition to potential enhancements in antioxidant defense, substrate metabolism, and being a rich source of many essential nutrients, we describe a possible positive relationship between PO intake and improved athletic performance and recovery in athletes after intense exercise by reducing inflammation, modulating the microbiome, neutralizing free radicals, and strengthening the cardiovascular system. However, more research in basic studies and clinical trials is needed to investigate PO’s clinical applications, mechanisms, and effects on athletes.

(Background) In the world of professional sports today, a major challenge is the demanding schedule that athletes face. To perform at their best in professional leagues, athletes must be in top shape every week for the demanding and lengthy games. This necessitates the use of tools and resources by strength and conditioning coaches to optimize individual recovery strategies for athletes. The article discusses the importance of recovery in sports performance and the benefits of implementing personalized recovery strategies for athletes. It provides methods and approaches for developing personalized recovery strategies, including athlete assessment and specific recovery techniques such as sleep, nutrition, hydration, stretching, massage, compression garments, and active recovery. (Purpose)The goal is to optimize an athlete's recovery and overall athletic performance by tailoring recovery strategies to their individual needs.(Methods) The present study employs a variety of research methods, including a review of existing literature, on-field investigations, and mathematical analysis, to investigate the current state of recovery tools and techniques that can assist in developing effective individualized recovery strategies. (Conclusion) This article emphasizes the importance of assessing an athlete's specific recovery needs, selecting appropriate recovery techniques, and monitoring outcomes to develop personalized recovery strategies. Coaches, trainers, and athletes should adopt a combination of approaches, such as the time-based and individualized approaches, to create effective recovery strategies that can be adjusted as needed to ensure peak performance and overall well-being.

Introduction and Aim of the ReviewMagnesium and zinc are vital for cellular metabolism and maintaining homeostasis, playing a particularly significant role for athletes. Magnesium, which is largely stored in bones and muscles, is essential for protein synthesis. Zinc, a critical trace element found in muscle and bone tissue, participates in over 300 enzymatic reactions, acts as an antioxidant and making both minerals crucial for physical performance. This study aims to explore the physiological role of magnesium (Mg) and zinc (Zn) in the context of athletic performance and to examine their impact on energy metabolism, muscle function, protein synthesis and potential benefits of Mg and Zn supplementation for improving athletic outcomes and post-exercise recovery. MethodsA comprehensive review of scientific literature was conducted through a thorough search of the PubMed database to explore the latest findings on the utility of magnesium and zinc in sports. Only articles in English were considered. Current KnowledgeThe review results indicate that Mg and Zn play critical roles in energy metabolism, muscle and immune system health. Mg deficiency can impair muscle function and reduce endurance, while its supplementation supports muscle relaxation, cardiovascular health, and respiratory efficiency. Although required in small amounts, Zn is indispensable for enzymatic activity, protein synthesis, hormonal balance, and muscle recovery, making it vital for post-exercise recovery and immune response modulation. ConclusionsAvailable data suggest that Mg and Zn supplementation may positively influence athletic performance, energy metabolism, and recovery post-exercise, though further research is needed to establish specific supplementation guidelines. This review provides a foundation for developing supplementation strategies aimed at enhancing athletic performance and supporting healthy recovery.

Balance and core stabilization exercises have often been associated with improved athlete performance and/or decreased incidence of injuries. While these exercises seem to be efficient in the prevention of injuries, there is insufficient evidence regarding their role in sport-specific performance and related functional movements. The aim of this scoping review is (1) to map the literature that investigates whether currently available variables of postural and core stability are functionally related to athlete performance in sports with high demands on body balance and spinal posture and (2) to identify gaps in the literature and suggest further research on this topic. The literature search conducted on MEDLINE, Scopus, Web of Science, PubMed, and Cochrane Library databases was completed by Google Scholar, SpringerLink, and Elsevier. Altogether 21 articles met the inclusion criteria. Findings revealed that postural stability plays an important role in performance in archery, biathlon, gymnastics, shooting, and team sports (e.g., basketball, hockey, soccer, tennis). Also core stability and strength represent an integral part of athlete performance in sports based on lifting tasks and trunk rotations. Variables of these abilities are associated with performance-related skills in cricket, cycling, running, and team sports (e.g., baseball, football, hockey, netball, soccer, tennis). Better neuromuscular control of postural and core stability contribute to more efficient functional movements specific to particular sports. Training programs incorporating general and sport-specific exercises that involve the use of postural and core muscles showed an improvement of body balance, back muscle strength, and endurance. However, there is controversy about whether the improvement in these abilities is translated into athletic performance. There is still a lack of research investigating the relationship of body balance and stability of the core with sport-specific performance. In particular, corresponding variables should be better specified in relation to functional movements in sports with high demands on postural and core stability. Identifying the relationship of passive, active, and neural mechanisms underlying balance control and spinal posture with athlete performance would provide a basis for a multifaced approach in designing training and testing tools addressing postural and core stability in athletes under sport-specific conditions.

Performance enhancement strategies in sport have frequently attempted to help athletes gain control over their thoughts and their emotions (Vealey, 1994) . These are 'content-focused' approaches try to change the content of the athlete's internal experience. Recently, increasing attention has been directed toward interventions that try to change an athlete's relationship with those internal experiences, instead of changing the content. These 'context-focused' approaches-including mindfulness and acceptance-based interventions - aim to help athletes perform well with anxiety, rather than trying to remove the anxiety (Gardner & Moore, 2012b) . These approaches promote similar acceptance of other unhelpful cognitions and emotions, such as anger or self-doubt. In this thesis, I aimed to explore the effectiveness of these approaches for promoting performance in sport. Chapter 1 identified the theories underlying context-focused approaches and outlined how they might reduce the likelihood of performance problems. For example, due to decreased self-focused attention, context-focused approaches may reduce the likelihood of choking due to explicit control of otherwise automatic skills. To see how well these theories held up to empirical exploration, Chapter 2 systematically reviewed the literature on context-focused approaches in sport. This review included prototypical context-focused approaches, like mindfulness, and also the wider range of approaches that operate by a similar mechanism, such as self-compassion. It found consistent trends in the research that these approaches improve athletic present-moment awareness, flow, performance, and help to reduce anxiety. It also revealed preliminary evidence for other outcomes like improved confidence and reduced rates of injury. However, none of the 66 studies met the Cochrane Collaboration criteria for low risk of bias (Higgins, Altman, Gotzsche, et al., 2011) . In Chapter 3, I aimed to test a brief context-focused intervention using a study design that met these Cochrane criteria. Golfers were randomised into either a acceptance-based intervention or a control condition. The study was double-blinded, randomised, prospectively registered with putting performance as the primary outcome. This study found few benefits of the acceptance-based intervention for performance, anxiety, or state mindfulness. It found a significant improvement on a secondary outcome: swing mechanics as measured by a SAM PuttLab (Science & Motion, 2016) . While brief interventions are well-established for testing context-focused interventions (Levin, Hildebrandt, Lillis, & Hayes, 2012) , Chapter 3 did not find strong evidence that a brief context-focused intervention leads to short-term improvements in sport performance. One barrier to testing interventions in sport is the questionnaire response burden placed on athletes. This is not unique to context-focused literature, because half of athletes in high-performance environments complete questionnaires every day (Taylor, Chapman, Cronin, Newton, & Gill, 2012) . However, in mindfulness and acceptance literature, reducing response burden would help researchers in many ways. Shorter measures allow researchers to assess more constructs in parallel, or assess the same construct more regularly (Basarkod, Sahdra, & Ciarrochi, 2018) . Many short measures fail to meet psychometric criteria (Smith, McCarthy, & Anderson, 2000) because the process of optimally shortening a questionnaire requires complex evaluations of many factors (Marsh, Ellis, Parada, Richards, & Heubeck, 2005) . As an alternative method, Chapter 4 demonstrated that an advanced machine learning algorithm can shorten athletic questionnaires without compromising reliability or validity. As an example of this process, the substantive-methodological synthesis presents multiple versions of the Mindfulness Inventory for sport. Although reliability was compromised when measures were very brief, shorter measures showed equivalent validity to the full measure. The resulting measures offer future researchers some alternate methods of measuring mindfulness that can be adapted to their needs. The paper also outlined ways for other researchers to efficiently shorten their own measures. Chapter 5 describes limitations of the previous chapters, but also identifies some ways in which researchers might assess the utility of context-focused approaches in the future. Many of these approaches require that athletes make significant investments in time. The thesis concludes that, although there is evidence these approaches might have widespread benefits inside and outside sport, it is not yet clear whether they are an effective use of time for optimising athletic performance.

<p dir="ltr">Background: Psychological interventions are applied in sports worldwide, although it is still unclear whether and which methods have an effect on sports performance. Acceptance and commitment therapy (ACT) is a behavioral change model that targets psychological processes related to acceptance, mindful awareness, and values-consistent behavior, and has been adapted for athletes. Further, using the internet format to deliver psychological services has had a great impact in clinical psychology, although it is still an underexplored format for delivering psychological interventions in sports.</p><p dir="ltr">Research aims: The overall aim of this thesis was to develop and evaluate the feasibility and preliminary effectiveness of an internet-based psychological intervention based on ACT (I-ACT) in an elite sports context (Studies II and III). It also aimed to develop and psychometrically evaluate a therapeutic tool and measure of values and values-based behavior in athletes (Study IV), and to review the current evidence regarding psychological interventions' effect on sports performance in athletes (Study I).</p><p dir="ltr">Methods and results: Study I: A systematic review was conducted of studies investigating psychological interventions' effect on sports performance in athlete samples. Five meta-analyses using cluster robust variance estimation were quantitatively synthesized for studies with comparable research designs. Significant moderate effects were found for PST, MA approaches, and Imagery compared to no-intervention controls. The effects were no longer significant in the sensitivity analyses when inferior research designs (non-randomized trials) were removed from the syntheses.</p><p dir="ltr">Study II: I-ACT was developed to focus on performance enhancement and to promote a psychologically sustainable sports participation. Four male elite ice hockey players took part in the intervention, and semi-structured interviews were conducted afterwards regarding their experiences. Data was analyzed using qualitative content analysis. Results suggest that I-ACT was feasible and acceptable in an elite sports context and relevant to their sport endeavor.</p><p dir="ltr">Study III: A total of 55 elite ice hockey players in two separate I-ACT intervention cohorts participated. Each intervention cohort (outfield players in I-ACT1 N = 40; outfield players in I-ACT2 N = 10) was compared with a statistical comparison group based on players from the rest of the leagues (N = 1051) regarding objective performance outcomes (goals, assists, Total points, and PlusMinus). Goaltenders (N = 5) were investigated with save percentage as the objective performance outcome. A significant moderate effect in I-ACT2 compared to the statistical comparison group was found for PlusMinus, and the significant effect lasted at follow-up. No significant effects were found for the objective performance outcomes in the other intervention cohort (I-ACT1), nor in I-ACT participating goaltenders. Significant small within-group effects were found for ice hockey-related psychological flexibility and sleep quality in I-ACT players. No significant effects were found regarding subjective performance, life quality, or general anxiety. Linear mixed-effects models were used to analyze the results, except for goaltenders' objective performance, for which a within-group repeated measures ANOVA was conducted.</p><p dir="ltr">Study IV: A therapeutic tool and measure of values and values-based behavior in athletes was developed called Bull's-Eye for Athletes (BEA). 155 athletes from junior elite to international senior level took part in the study. BEA was administered digitally and psychometrically evaluated using Rasch analysis. BEA demonstrated satisfactory psychometric properties in general regarding unidimensionality, local independence, invariance, and response category monotonicity. Although the results should be interpreted while considering the limited sample size.</p><p dir="ltr">Conclusions: The effects of PST, MA approaches, and Imagery on athletic performance are unstable and should be interpreted with caution, and further randomized trials are required (Study I). The internet format was a feasible option for delivering an internet-based psychological intervention in elite athletes (Study II). I-ACT had an effect on objective sports performance in one out of two intervention cohorts. The results should be interpreted carefully in general, and I-ACT should be further evaluated in an RCT while also investigating mediators of change related to the ACT model (Study III). BEA offers a therapeutic tool and measure of values and values-based behavior in athletes. It demonstrated satisfactory psychometric properties in an initial psychometric evaluation. It should, however, be further evaluated with larger samples in various sports contexts and also in a longitudinal intervention study as a measure of values-based behavioral change in athletes (Study IV).</p><h3>List of scientific papers</h3><p dir="ltr">I. <b>Reinebo, G.</b>, Alfonsson, S., Jansson-Fröjmark, M., Rozental, A., & Lundgren, T. (2024). Effects of psychological interventions to enhance athletic performance: A systematic review and meta-analysis. Sports Medicine, 54, 347-373. <a href="https://doi.org/10.1007/s40279-023-01931-z" rel="noreferrer" target="_blank">https://doi.org/10.1007/s40279-023-01931-z</a><br></p><p dir="ltr">II. <b>Reinebo, G.</b>, Björverud, L. G., Parling, T., Andersson, G., Jansson- Fröjmark, M., & Lundgren, T. (2024). Development and experiences of an internet-based acceptance and commitment training (I-ACT) intervention in ice hockey players: a qualitative feasibility study. Frontiers in Sports and Active Living, 6, 1297631. <a href="https://doi.org/10.3389/fspor.2024.1297631" rel="noreferrer" target="_blank">https://doi.org/10.3389/fspor.2024.1297631</a></p><p dir="ltr">III. <b>Reinebo, G.</b>, Jansson-Fröjmark, M., Parling, T., Andersson, G., Lindner, P., Lundgren, T. (in press). Internet-based acceptance and commitment therapy (I-ACT) for elite ice hockey players: A quasi-experimental multiple-cohort intervention study. International Journal of Sport and Exercise Psychology. <a href="https://doi.org/10.1080/1612197X.2025.2531840" rel="noreferrer" target="_blank">https://doi.org/10.1080/1612197X.2025.2531840</a></p><p dir="ltr">IV. <b>Reinebo, G.</b>, Johansson, M., Jansson-Fröjmark, M., Wiklund, A., Ekman Öhrn, G., Parling, T., Rozental, A., Andersson, G., & Lundgren, T. Bull's-Eye for Athletes (BEA): A measure of values-based behavior in sport and a psychometric evaluation using Rasch analysis. [Manuscript]</p>