پژوهشگاه تربیت بدنی و علوم ورزشی (وزارت علوم ، تحقیقات و فناوری) فیزیولوژی ورزشی 2322-164X 16 62 2024 06 21 The Endurance Athletes' Paradox: Relationship between Muscle Tissue Fat Accumulation and Insulin Sensitivity in Endurance Athletes and Obese Individuals پارادوکس ورزشکاران استقامتی: ارتباط بین تجمع چربی بافت عضلانی و حساسیت انسولین در ورزشکاران استقامتی و افراد چاق 17 37 4446 10.22089/spj.2024.17168.2332 FA حمید محبی استاد فیزیولوژی ورزشی، دانشکده تربیت‌بدنی و علوم ورزشی، دانشگاه گیلان، رشت، ایران 0000-0001-9858-5964 سید مرتضی حسینی دکتری تخصصی فیزیولوژی ورزشی، دانشکده تربیت‌بدنی و علوم ورزشی، دانشگاه گیلان، رشت، ایران 0009-0006-0024-2052 Journal Article 2024 08 26 Introduction The relationship between intramyocellular lipid (IMCL) content and insulin sensitivity presents a fascinating paradox. In obese and diabetic individuals, elevated IMCL levels are associated with insulin resistance, impaired glucose uptake, and metabolic dysfunction. Conversely, endurance athletes, despite having higher IMCL levels, exhibit enhanced insulin sensitivity and superior metabolic health. This paradox underscores the complex interplay between IMCL, muscle fiber composition, lipid droplet proteins, and cytokines in determining metabolic outcomes. This review explores the mechanisms underlying the endurance athlete's paradox, focusing on the roles of muscle fiber types, lipid droplet-associated proteins, and myokines such as interleukin-6 (IL-6) and interleukin-15 (IL-15). By elucidating these mechanisms, we aim to provide insights into potential therapeutic strategies for improving insulin sensitivity in obese populations. This narrative review synthesizes findings from peer-reviewed studies on IMCL, lipid droplet proteins, and myokines in the context of insulin sensitivity and muscle metabolism. Key databases, including PubMed, Web of Science, and Google Scholar, were searched for relevant literature up to September 2024. Studies were selected based on their relevance to IMCL, muscle fiber types, lipid droplet proteins, and myokines in endurance athletes and obese individuals. The role of exercise training on muscle fat content As obesity and fat reserves increase, insulin sensitivity tends to decrease. Diabetic and obese individuals have higher levels of Intramyocellular Lipid (IMCL) compared to lean individuals. The increased intra-muscular fat content in obese individuals can impair glucose uptake by muscles, which may reduce insulin sensitivity. Interestingly, despite the higher fat content in their muscles, the oxidation of fatty acids appears to be impaired in obese individuals. Studies suggest that the skeletal muscle of obese individuals lacks the metabolic adaptation necessary to respond effectively to lipid exposure. This may result from an inability to enhance mitochondrial respiration in the presence of lipid substrates, as well as a failure to induce mitochondrial proliferation. However, it seems that endurance athletes are an exception. Their muscles contain more IMCL than those of lean individuals. It is a debated topic as to why the increase in triacylglycerol (TAG) in endurance athletes is linked with improved insulin sensitivity, while in obese and diabetic individuals, it is associated with increased insulin resistance. This paradox highlights the complex relationship between IMCL, metabolism, and insulin resistance in different populations. Since the amount of type I fibers in insulin-sensitive obese people is higher than in insulin-resistant obese people, it is believed that type I fibers have a higher buffering ability for increased levels of IMCL, so they can prevent increased levels of ceramide and lipotoxicity. It has been shown that the content of IMCL in the subsarcolemma (SS) of type II fibers of diabetic subjects is four times higher than that of exercised subjects. It is proposed that in type II muscle fibers IMCL content, size and number of SS area LDs are negatively related to insulin sensitivity. The role of lipid droplet proteins in endurance athletes' paradox Lipid droplets in muscle tissue are surrounded by proteins essential for their metabolism and signaling. These proteins help mediate interactions with other cellular components and regulate the droplets' positioning. Studies suggest lipid droplets can recruit proteins for fat hydrolysis or storage. Decreased perilipin 3 (PLIN3) levels in obese individuals may lead to higher intramyocellular lipid (IMCL) levels, while PLIN2 is typically lower in lean than in obese individuals. Research indicates that PLIN2-deficient mice are resistant to diet-induced obesity. This resistance can be attributed to a reduction in food consumption and an increase in physical activity levels. Additionally, evidence suggests that genetic inhibition of PLIN2 is associated with a decrease in the size of lipid droplets. In general, the content of PLIN2 is observed to increase in individuals with higher levels of adiposity. Endurance athletes, characterized by an elevated fat oxidation rate and increased levels of PLIN5, are believed to enhance PLIN5 expression in muscle cells in response to exercise stimuli. Conversely, it is noted that muscle cells in lean individuals and those with diabetes are inclined to elevate PLIN3 levels. It is posited that the skeletal muscles of athletes utilize PLIN5 to facilitate the storage of fat reserves, subsequently optimizing the oxidation of fat droplets for energy. This hypothesis may be elucidated through the interaction between PLIN5 and adipose triglyceride lipase (ATGL). PLIN5 demonstrates an ability to associate with ATGL, and its capacity to sequester ATGL at the membrane highlights the critical role that PLIN5 plays in lipase activity. The role of IL-6 and IL-15 in endurance athletes' paradox Changes in body composition correlate with alterations in cytokine secretion, particularly interleukin-6 (IL-6), a pro-inflammatory cytokine crucial for immune response. Research shows that muscle-derived IL-6 is linked to lipid metabolism rather than inflammation, and while obesity is associated with higher IL-6 levels, IL-6 may also facilitate intramuscular fat storage. IL-15, another important myokine, helps regulate fat metabolism in skeletal muscles and is linked to reduced adipocyte fat accumulation. Circulating IL-15 levels negatively correlate with body fat mass. While training status can influence the IL-6 response to exercise, it's less significant than factors like training intensity and duration. Notably, exercise increases IL-15 levels, but training does not affect its baseline levels. Conclusion The relationship between intramuscular fat content and insulin sensitivity presents a complex paradox, particularly when comparing obese individuals to endurance athletes. Research indicates that while both groups exhibit higher levels of IMCL, the implications for insulin sensitivity differ significantly. In obese individuals, increased IMCL is associated with impaired glucose uptake and reduced insulin sensitivity, potentially due to a lack of metabolic adaptation and mitochondrial dysfunction in response to lipid exposure. Conversely, endurance athletes, despite having greater IMCL, demonstrate improved insulin sensitivity, suggesting that the context of fat accumulation such as the size and location of lipid droplets, the presence of specific proteins like PLIN and the roles of myokines such as IL-6 and IL-15 plays a critical role in metabolic outcomes. The differential effects of IMCL on metabolism highlight the necessity for further research to elucidate the underlying mechanisms that allow endurance athletes to utilize intramuscular fat effectively while avoiding the metabolic dysfunction observed in obesity. Understanding these distinctions may provide insights into potential therapeutic strategies for improving insulin sensitivity in obese populations. Article Message It appears that the mere increase in intramuscular fat content does not significantly contribute to heightened insulin resistance. The literature suggests that factors such as the specific locations of fat storage, the size of fat droplets, the types of bioactive lipids present, metabolic adaptation, associated coat proteins, and cytokines may contribute to the observed paradox of muscle fat accumulation in endurance athletes. Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. Authors' Contributions All authors participated in designing, implementing, and writing all parts of the present study. Conflict of Interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Acknowledgments The researchers wish to extend their sincere appreciation to the esteemed officials of the Faculty of Physical Education and Sports Sciences at Guilan University. تجمع چربی سبب میشود چربی در بافتهایی به‌جز بافت ذخیره چربی (ادیپوز) مانند عضله نیز انباشت شود. در سلولهای عضلانی چربی به صورت قطرات چربی ذخیره میشود. در سلولهای عضلانی قطرات چربی این توانایی را دارند که چربی را به شکل مطمئن ذخیره کنند، اما این ظرفیت دارای محدودیت است؛ به‌گونه‌ای‌که افزایش بیش از اندازه ذخیره چربی ممکن است به اختلال در عملکرد طبیعی سلول منجر شود. با افزایش وزن و چاقی میزان محتوای چربی درون سلولهای عضلانی افزایش مییابد و این موضوع با مقاومت به انسولین ارتباط مستقیم دارد، اما این پدیده در ورزشکاران استقامتی متفاوت است؛ به‌گونه‌ای‌که بهرغم افزایش محتوای چربی درون‌عضلانی، افزایش حساسیت به انسولین مشاهده میشود. احتمالاً محل ذخیره چربی، محتوای چربی و ترکیب قطرات چربی، همراه باوجود لیپیدهای بیواکتیو ممکن است بین ورزشکاران و افراد چاق و احتمالا دارای دیابت نوع دو متفاوت باشد. پروتئین‌هایی که سطح قطرات لیپید را میپوشانند، احتمالاً بر سیگنال دهی و متابولیسم آن‌ها تأثیر میگذارند. این پروتئینها همچنین به تعامل بین قطرات لیپید و سایر اجزای سلولی و همچنین موقعیت آن‌ها کمک میکنند. این مقاله با مرور تحقیقات قبلی درمورد ارتباط بین قطرات چربی در عضلات اسکلتی و اختلالات متابولیک، نقش پروتئین‌ها را در تنظیم متابولیسم و اثرات فعالیت بدنی بر این اندامک‌ها و تفاوت در تجمع چربی در بافت عضلانی بین ورزشکاران و افراد چاق یا دارای دیابت نوع 2 بررسی می‌کند.

https://spj.ssrc.ac.ir/article_4446_0887f1a5b9970ad13f46b8c1485f7900.pdf

پژوهشگاه تربیت بدنی و علوم ورزشی (وزارت علوم ، تحقیقات و فناوری) فیزیولوژی ورزشی 2322-164X 16 62 2024 06 21 The Effect of a Movement Program with a Lighted Stepping Board on Cortisol Levels and Sleep Disorders in Children with Autism Spectrum Disorder تأثیر یک دوره برنامۀ حرکتی با جدول نوری گام‌برداری بر سطح کورتیزول و اختلالات خواب کودکان مبتلا به اختلال طیف اوتیسم 38 52 4448 10.22089/spj.2024.14047.2225 FA سعید صادقی دینانی گروه فیزیولوژی ورزشی، دانشکده تربیت بدنی و علوم ورزشی، دانشگاه اصفهان، اصفهان، ایران 0000-0002-1391-0017 سید محمد مرندی گروه فیزیولوژی ورزشی، دانشکده تربیت بدنی و علوم ورزشی، دانشگاه اصفهان، اصفهان، ایران 0000-0003-3877-870x زهرا آقاکوچکی گروه حرکات اصلاحی و آسیب شناسی ورزشی، دانشکده تربیت بدنی و علوم ورزشی، دانشگاه اصفهان، اصفهان، ایران 0000-0001-7990-5600 محمد جواد مراتی گروه برق و الکترونیک، دانشکده برق و الکترونیک، موسسه صفاهان، اصفهان، ایران شریفه موسوی استادیار، گروه پرستاری بهداشت روان، واحد خوراسگان اصفهان، دانشگاه آزاد اسلامی، اصفهان، ایران Journal Article 2022 12 12 Background and Purpose Autism spectrum disorder (ASD) is a neurodevelopmental condition that affects various physical, motor, cognitive, and psychological dimensions. Stress and sleep disturbances are common issues among individuals with ASD, significantly impacting their quality of life. Sensory-motor integration-based rehabilitation methods are widely used to address these challenges, as they help children process sensory input more efficiently, reducing stress and improving adaptive behaviors. Technology-based interventions, such as electronic devices and visual-auditory feedback systems, have shown promise in engaging children with ASD.Building on these findings, this study introduces a novel exercise method using a lighted stepping board, which provides visual and auditory feedback to simplify and enhance motor patterns. The program aims to improve sensory-motor integration, reduce stress, and address sleep disturbances in children with ASD. The primary objective of this study is to determine the effect of a 12-week movement program using a lighted stepping board on cortisol levels (a biomarker of stress) and sleep disturbances in children with ASD. Materials and Methods This semi-experimental study involved 20 children with moderate ASD, aged 6 to 12 years, and an IQ above 75. Participants were randomly assigned to two groups: 1) Experimental Group that performed the movement program using a lighted stepping board; 2) Control Group that performed the same program using a simple, non-lighted board. The movement program consisted of four 45-minute sessions per week for 12 weeks, conducted under the supervision of trained instructors. The lighted stepping board provided visual and auditory feedback, guiding children through progressively complex walking patterns. Cortisol levels were measured via saliva samples collected at pre-test and post-test. Sleep disturbances were assessed using the Pittsburgh Sleep Quality Index (PSQI). Data were analyzed using analysis of covariance (ANCOVA) to compare post-test results between groups, controlling for pre-test scores. Statistical significance was set at p≤0.05. Findings The results revealed significant differences between the experimental and control groups. The experimental group showed a significant reduction in cortisol levels compared to the control group (p=0.018). The effect size of the intervention on cortisol levels was 28.6%. The experimental group demonstrated a significant improvement in sleep quality compared to the control group (p=0.032). The effect size of the intervention on sleep disturbances was 24.4%. These findings indicate that the lighted stepping board program effectively reduced stress and improved sleep quality in children with ASD. Conclusion The study demonstrates that the lighted stepping board program is an effective intervention for reducing cortisol levels and sleep disturbances in children with ASD. The visual and auditory feedback provided by the board enhances sensory-motor integration, making the exercises more engaging and effective. The program's ability to lower cortisol levels suggests its potential as a stress management tool for children with ASD. By addressing sensory-motor integration and reducing stress, the program indirectly improves sleep quality. The lighted stepping board can be integrated into existing rehabilitation programs to enhance their effectiveness. It can be suggested that the lighted stepping board is a cost-effective and space-efficient tool that can be used at home to support children with ASD. Also, the program can be incorporated into sensory-motor integration therapies to enhance outcomes. Article Message This study highlights the therapeutic potential of step-pattern motor exercises using a lighted stepping grid in children with autism spectrum disorder. The intervention, which integrates visual and auditory feedback, was found to significantly reduce salivary cortisol levels an indicator of physiological stress and alleviate sleep disturbances as measured by the Pittsburgh Sleep Quality Index. These findings suggest that combining motor coordination tasks with multisensory stimuli may promote neurophysiological regulation and improve overall well-being in children with autism. As a result, such structured, technology-enhanced movement programs can serve as an effective, non-pharmacological strategy in autism rehabilitation settings. Ethical Considerations Prior to the commencement of the study, ethical approval was obtained from the Ethics Committee of the University of Isfahan under the code IR.UI.REC.1398.032. The study adhered to the ethical principles outlined in the Helsinki Declaration. Authors’ Contributions All authors contributed to the design, implementation, and writing of all sections of the present study. Conflict of Interest The authors declare that there is no conflict of interest regarding the publication of this article. Acknowledgments The authors sincerely thank all individuals who contributed to the implementation of this research. مطالعه حاضر با هدف تعیین اثر یک دوره برنامه حرکتی با جدول نوری گام‌برداری بر سطح کورتیزول و اختلالات خواب کودکان مبتلا به اختلال طیف اوتیسم انجام شد. در این مطالعه نیمه‌تجربی، 20 کودک مبتلا به اختلال طیف اوتیسم با رده سنی 6 تا 12 سال به صورت تصادفی در دو گروه ده‌نفری (گروه تمرین با جدول نوری و کنترل) قرار گرفتند. گروه تمرین با جدول نوری و گروه کنترل با صفحه‌ ساده برنامه حرکتی الگوهای گام‌برداری را به مدت دوازده هفته به صورت چهار جلسه 45 دقیقه‌ای در هفته زیرنظر مربیان خود دریافت کردند. اندازه‌گیری کورتیزول به ‌صورت بزاقی و ارزیابی اختلالات خواب با پرسشنامه پیتزبورگ در دو نوبت پیش‌آزمون و پس‌آزمون برای هر دو گروه انجام شد. داده‌ها با تحلیل کوواریانس در سطح معناداری (05/0>P) تجزیه و تحلیل شد. نتایج نشان داد که در پس‌آزمون میانگین سطح کورتیزول در گروه تمرین با جدول نوری در مقایسه با گروه کنترل کاهش معنا‌داری داشت (018/0P=). همچنین کاهش معناداری در نمره اختلالات خواب در گروه تمرین با جدول نوری در مقایسه گروه کنترل مشاهده شد (032/0P=). براساس نتایج این پژوهش، در صورت ارائه تمرینات مربع گام‌برداری همراه با بازخورد دیداری و شنیداری حاصل از فناوری، می‌توان شاهد تغییرات معناداری در کاهش سطح کورتیزول و اختلالات خواب کودکان مبتلا به اختلال طیف اوتیسم بود.

https://spj.ssrc.ac.ir/article_4448_53e19f3dbb211f20b20b45668303c1b6.pdf

پژوهشگاه تربیت بدنی و علوم ورزشی (وزارت علوم ، تحقیقات و فناوری) فیزیولوژی ورزشی 2322-164X 16 62 2024 06 21 Influence of Exercise Training on Expression of Some Cerebral Proteins Involved in APP Processing in Rat Models of Alzheimer's Disease: A Meta-Analysis اثر تمرینات ورزشی بر بیان برخی پروتئین‌های پردازش APP مغز در موش‌های مدل بیماری آلزایمر: مطالعۀ فراتحلیل 53 78 4499 10.22089/spj.2024.17202.2333 FA نرگس خطیبی کارشناسی ارشد، گروه علوم ورزشی، دانشکده علوم تربیتی و روانشناسی، دانشگاه شهید مدنی آذربایجان، تبریز، ایران 0009-0003-4380-2118 بهلول قربانیان دانشیار، گروه علوم ورزشی، دانشکده علوم تربیتی و روانشناسی، دانشگاه شهید مدنی آذربایجان، تبریز، ایران 0000-0001-5885-8921 کریم آزالی علمداری دانشیار، گروه فیزیولوژی ورزشی، دانشکده تربیت بدنی و علوم ورزشی، دانشگاه شهید مدنی آذربایجان، تبریز، ایران 0000-0002-6134-1912 Journal Article 2024 09 01 Background and Purpose Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by the accumulation of amyloid plaques and neurofibrillary tangles in the brain. The amyloid-β (Aβ) peptide, derived from the cleavage of amyloid precursor protein (APP), is a key therapeutic target in AD. APP is processed via two pathways: the non-amyloidogenic pathway, mediated by α-secretase (ADAM10), and the amyloidogenic pathway, mediated by β-secretase (BACE1). The balance between these pathways determines Aβ production, with dysregulation contributing to AD pathogenesis. Exercise on the other hand has been shown to modulate APP processing, shifting it toward the non-amyloidogenic pathway to reduce Aβ production. However, the underlying mechanisms is poorly understood. This study aimed to systematically review and meta-analyze the effects of exercise training on cerebral ADAM10, BACE1, sAPPα, sAPPβ, and Aβ expression, as well as spatial memory function in rat models of AD. Materials and Methods This systematic review and meta-analysis followed PRISMA guidelines. Animal studies with control groups investigating the effects of at least 3 weeks of exercise training in rat models of AD, published in peer-reviewed journals up to July 2024, were retrieved from PubMed, Google Scholar, SID, and Magiran databases. Studies combining exercise with other interventions, Duplicate publications and review articles were excluded from analysis. Two reviewers independently screened titles and abstracts for eligibility. Disagreements were resolved through consultation with a third reviewer. Random-effects model was used to calculate standardized mean differences (SMD) and 95% confidence intervals (CIs). Heterogeneity was assessed using the I² statistic, with values >50% indicating high heterogeneity. Publication bias was evaluated using Egger’s regression test. Meta-regression and subgroup analyses were performed to explore the effects of moderators. Findings A total of 14 interventions were included in the meta-analysis. Primary Outcome measure was Cerebral ADAM10 Expression. High heterogeneity (I² > 50%) was observed for all outcomes. Egger’s regression indicated no significant publication bias. The net effect of exercise training on ADAM10 expression was not statistically significant (SMD = 0.73, 95% CI: -0.43 to 1.91). moreover, subgroup analysis revealed a significant increase in hippocampal ADAM10 expression (SMD = 2.48, p = 0.001). Secondary Outcomes are listed below: Cerebral BACE1 Expression: No significant overall effect was observed. Subgroup analysis showed a significant decrease in hippocampal BACE1 expression (SMD = -2.03, p = 0.001). sAPPα and sAPPβ Expression: Exercise training significantly reduced sAPPβ expression (SMD = -2.59, 95% CI: -3.80 to -1.39). No significant effect was observed for sAPPα. Aβ Expression: Exercise training significantly reduced Aβ expression (SMD = -4.03, 95% CI: -5.13 to -2.92). Spatial Memory Function: Exercise training improved spatial memory function, though heterogeneity was high. Conclusion The findings suggest that exercise training modulates APP processing in rat models of AD, favoring an elevated hippocampal non-amyloidogenic pathway, based on a significant increase in ADAM10 expression in this region. On the other hand, a dimineshed hippocampal BACE1 expression could be indicate on a suppressed amyloidogenic pathway which is thought to can reduced cerebral Aβ burden. Other finding of this study was related to a significant decrease in Aβ expression which is in line with our previous findings to reduce amyloid burden. The exact mechanisms of exercise training in reduction of cerebral Aβ burden was attributed to induce a shif in APP processing toward the non-amyloidogenic pathway through upregulation of ADAM10 and downregulation of BACE1. Morereover, exercise-induced increases in brain-derived neurotrophic factor (BDNF) may further modulate APP processing and reduce Aβ production. However, this study has some limmitations e.g high heterogeneity across studies that limits the generalizability of the findings. Furthuremore, most of included studies used rodent models, which their results can not be fully generalizable to human patients. Additionally, variability in exercise protocols and outcome measures may contribute to inconsistent results. Anyway, exercise training shows promise as a non-pharmacological intervention for reducing amyloid burden in AD, however, more clinical trials remain to be provided in human subjects. The observed increases in ADAM10 and converse decreases in BACE1 and Aβ expression, particularly in the hippocampus, suggest that exercise may mitigate amyloid pathology in early AD stages. For future research it is suggested to conduct longitudinal studies to assess the long-term effects of exercise on APP processing and Aβ levels. Moreover, investigating the straight role of exercise-induced BDNF in modulating APP processing could be instumental. Additionally, it seems exact exploration the effects of different exercise modalities (e.g., aerobic, resistance) on AD biomarkers should be conducted in the future studies in thia area. Article Message Increased expression of ADAM10 and decreased expression of BACE1 in the hippocampus, along with reduced sAPPβ and Aβ levels in mixed brain tissue samples of AD modes due to exercise training, herald a potential reduction in cerebral amyloid burden, especially in the early stages of AD; however, these findings still need to be confirmed in human patients. Acknowledgments Thanks, and appreciation are extended to all individuals or groups who collaborated in conducting this research. Conflict of interest The authors declare no competing interests regarding the publication of this article. هدف این مطالعه، تعیین اندازه اثر تمرینات ورزشی بر بیان پروتئین‌های ADAM10 (پیامد اصلی) و BACE1، sAPPα، sAPPβ و Aβ (پیامدهای فرعی) در مغز موش‌های مدل AD و انجام تحلیل‌های طبقه‌ای و فرارگرسیون بر حسب متغیرهای تعدیل‌کننده بود. مداخلات بررسی‌کننده تأثیر تمرین ورزشی دارای مدت زمان بیش از سه‌هفته بر موش‌های مدل آلزایمر (AD) منتشرشده در مجلات پژوهشی فارسی و انگلیسی تا جولای 2024، از سایت‌های Google، SID و Magiran و Pubmed جستجو و تحلیل شدند. مدل اثرات تصادفی برای تعیین اندازه‌ اثر (SMD با تناوب اطمینان %95) مداخلات (n=14) سنجش‌کننده‌ بیان پروتئین ADAM10، BACE1، sAPPα، sAPPβ و Aβ مغزی با نرم‌افزار CMA2 استفاده شد. I2 بیشتر از 50 درصد، مبنای وجود هتروژنیتی زیاد قرار گرفت و سوگیری انتشار با تست اِگِر بررسی شد. همبستگی بین اندازه اثر تمرینات بر بیان ADAM10 و BACE1 مغز، با ضریب پیرسون و رگرسیون بین دو اندازه اثر فوق با سن موش‌ها و طول مدت تمرینات با فرارگرسیون مدل اثر لحظه‌ای بررسی شد. همچنین درمورد بیان ADAM10 و BACE1 سنجش‌شده در بین سه ناحیه مختلف مغز، تحلیل طبقه‌ای انجام شد. یافته‌ها نشان داد که در تمام پیامدها مقدار هتروژنیتی در بین نتایج تحقیقات، زیاد بود. اندازه اثر کل مداخلات مورد شمول (n=14) درمورد بیان پروتئین ADAM10 مغز پس از تحلیل سوگیری انتشار (SMD=0.73, CI95%: -0.43 to 1.91) معنادار نشد (با توجه به تناوب اطمینان)، اما درمورد پیامدهای فرعی، اندازه اثر حاصل‌شده نهایی درمورد sAPPβ (SMD= -2.59, CI95%: -3.80 to -1.39) و Aβ (SMD= -4.03, -2.92 to -5.13) مغز معنا‌دار شد. در تحلیل‌های طبقه‌ای (n=7)، بیان ADAM10 (SMD= 2.48, p=0.001) و BACE1 (SMD= -2.03, p=0.001) فقط در هیپوکامپ معنا‌دار بود. نتیجه‌گیری می‌شود، هتروژنیتی زیاد، در کل یافته‌ها بیان می‌کند که هنوز باید تحقیقات بیشتری در این زمینه انجام شود. افزایش بیان ADAM10 و کاهش بیان BACE1 در هیپوکامپ همراه با کاهش sAPPβ و Aβ در کل بافت مغز موش‌های مدل AD در اثر تمرینات ورزشی، نویدبخش کاهش بار آمیلوئید مغزی و به‌ویژه در مراحل اولیه AD است؛ اگرچه این یافته‌ها هنوز باید در جمعیت انسانی تأیید شود.

https://spj.ssrc.ac.ir/article_4499_5e51eeda0422de44a7cc260b4239d4f9.pdf

پژوهشگاه تربیت بدنی و علوم ورزشی (وزارت علوم ، تحقیقات و فناوری) فیزیولوژی ورزشی 2322-164X 16 62 2024 06 21 The Effect of Acute Consumption of Beetroot Juice Supplement on Anaerobic Performance Indices in Trained Subjects: A Systematic Review and Meta-Analysis تأثیر مصرف حاد مکمل آب چغندر بر شاخص‌های عملکرد بی‌هوازی در افراد تمرین‌کرده: یک مرور نظام‌مند و فراتحلیل 79 104 4503 10.22089/spj.2025.17059.2327 FA نفیسه حسن پور دانشجوی دکتری فیزیولوژی ورزشی، دانشکدة علوم ورزشی و تندرستی، دانشگاه تهران، تهران، ایران 0009-0002-8711-0327 فاطمه کاظمی نسب استادیار فیزیولوژی ورزشی، گروه تربیت بدنی و علوم ورزشی، دانشکده علوم انسانی، دانشگاه کاشان، کاشان، ایران 0000-0002-7309-3637 Journal Article 2024 07 31 Background and Purpose Beetroot juice (BRJ) is rich in dietary nitrates (NO₃⁻) and has gained popularity for its potential ergogenic properties. Nitrates are converted to nitric oxide (NO) in the body, which enhances blood flow, oxygen delivery, and mitochondrial efficiency, potentially improving exercise performance. While BRJ has been extensively studied for its effects on aerobic performance, its impact on anaerobic performance—characterized by short-duration, high-intensity activities—remains less understood. Anaerobic performance metrics, such as peak power, minimum power, mean anaerobic power, and fatigue index, are critical for athletes in sports requiring explosive strength and speed. Despite the growing interest in BRJ as a performance-enhancing supplement, there has been no systematic evaluation of its acute effects on anaerobic performance in trained individuals. This study aims to systematically review and meta-analyze the existing literature to determine whether acute BRJ supplementation influences anaerobic performance indicators in trained subjects. Materials and Methods This research adhered to the PRISMA guidelines for systematic reviews and meta-analyses. Relevant articles in English and Persian were retrieved from databases including PubMed, Web of Science, Google Scholar, SID, and Magiran, up to September 2024. Eligibility criteria were as below: Studies involving trained individuals. Use of cross-over designs. Reporting of anaerobic performance metrics (e.g., peak power, minimum power, mean anaerobic power, fatigue index). Sample demographics (age, gender, BMI), type and dosage of BRJ supplementation, and anaerobic performance outcomes were extracted. A random-effects model was used to calculate standardized mean differences (SMD) and 95% confidence intervals (CIs). Heterogeneity was assessed using the I² statistic. Publication bias was evaluated through funnel plots and Egger's test. Results A total of 11 studies involving 140 participants (42 women and 98 men) met the inclusion criteria. The average age of participants ranged from 20.3 to 30.86 years, and BMI ranged from 20.41 to 24.21. Among them, Hassanpour et al. investigated both 70 mL and 140 mL doses of beetroot juice; Hashemifard et al. examined a 100 mL dose; and Conger et al. assessed a single dose of beetroot juice powder. Seven studies evaluated a 70 mL dose of beetroot juic. Tatlıcı and Cakmakci administered beetroot supplementation at a dose of 2 grams per kilogram of body weight, and Baumann examined beetroot juice in volumes ranging from 235 to 355 mL. Five studies administered the supplement dose three hours prior to the experimental protocol, while three studies administered it two hours before the protocol. Additionally, Hashemi Fard et al. administered the dose 1.5 hours before the experimental protocol; Tatlici et al., 2.5 hours before; and Baumann et al., between 2.5 to 3 hours prior to the experimental procedure. Key results are as below: Peak Power: [SMD = -0.109 (-0.33 to 0.11), P = 0.33], I2=32.703, P=0.12 Minimum Power: [SMD = -0.120 (-0.32 to -0.08)], P = 0.25, I2=0.00, P=0.53 Mean Anaerobic Power: [SMD = -0.134 (-0.30 to -0.03), P=0.13], I2=3.922, P=0.40 Fatigue Index: [SMD = -0.105 (-0.46 to -0.25), P=0.56], I2=53.807, P=0.04 Subgroup Analyses demonstrated that variations in BRJ consumption timing and dosage did not influence outcomes. Also, consistent results were observed across studies using standardized tests like the Wingate Anaerobic Test (WAnT) and Running-Based Anaerobic Sprint Test (RAST). Heterogeneity was moderate to high (I² = 45–65%); and, funnel plots and Egger's test indicated no significant publication bias. Conclusions The findings suggest that acute BRJ supplementation does not significantly enhance anaerobic performance in trained individuals. While BRJ is rich in nitrates, which are known to improve blood flow and oxygen delivery, these effects may not translate to short-duration, high-intensity activities that rely primarily on anaerobic energy systems. Duration of Activity: Anaerobic performance relies on immediate energy sources (e.g., ATP-PCr and glycolytic systems), which may not benefit significantly from increased NO availability. Timing of Supplementation: Acute BRJ consumption may not provide sufficient time for nitrate conversion to NO and subsequent physiological effects. Training Status: Trained individuals may already have optimized physiological adaptations, limiting the ergogenic potential of BRJ. Unlike aerobic performance, which benefits from enhanced oxygen utilization and mitochondrial efficiency, anaerobic performance is less dependent on these mechanisms. This may explain the lack of significant effects observed in this study. The study had some limitations that may affect he results, included: Variability in study designs, BRJ dosages, and participant characteristics may have influenced results; The limited number of studies and participants may reduce the generalizability of findings; The review focused on acute effects, leaving the potential benefits of chronic BRJ supplementation unexplored. Article Message The findings of the present study indicate that acute beetroot supplementation cannot be considered a definitive strategy for enhancing anaerobic performance in trained individuals. Therefore, it is suggested that although trained individuals who are eager to benefit from the remarkable effects and therapeutic properties of beetroot—and athletes and coaches who, in line with the International Olympic Committee's position, seek to observe improvements in anaerobic performance and its related indices—may be interested in its use, the current evidence does not support the efficacy of acute supplementation in this population. It is likely that short-term or chronic supplementation protocols, administered over longer durations or at higher doses, may be required to achieve meaningful effects. Funding The present meta-analysis did not receive funding from any organization. Authors’ Contributions All authors contributed to the design, execution, and writing of all sections of this study. Conflict of Interest The authors declare no conflict of interest. Acknowledgement We would like to thank the authors who provided the data of their studies آب چغندر (BRJ) سرشار از نیترات‌های معدنی (NO3-) است که دارای خواص ارگوژنیک است؛ بااین‌حال، در حال حاضر هیچ تحلیل سیستماتیکی برای ارزیابی اثرات مکمل نیترات حاد، به‌طور انحصاری بر عملکرد بی‌هوازی در افراد تمرین کرده و ورزشکار وجود ندارد؛ ازاین‌رو هدف مطالعه حاضر، بررسی نظام‌مند متون فعلی و ارزیابی تأثیر مصرف حاد مکمل آب چغندر بر شاخص‌های عملکرد بی‌هوازی در افراد تمرین‌کرده به صورت فراتحلیل بود. جستجوی سیستماتیک متون برای مقالات انگلیسی و فارسی تا شهریور ماه 1403 انجام شد. تفاوت میانگین و فاصله اطمینان ۹۵% (CI) با استفاده از مدل اثر تصادفی محاسبه شد. تعداد 11 مطالعه با 140 بزرگسال جوان سالم ورزشکار یا تمرین‌کرده (42 زن و 98 مرد)، با میانگین سنی 3/20 الی 86/30 و میانگین BMI 41/20 الی 21/24 وارد فراتحلیل حاضر شد. نتایج نشان داد، مصرف حاد مکمل آب چغندر قرمز بر شاخص‌های عملکرد بی‌هوازی اعم از توان بیشینه ]33/0P=، 109/0-=[SMD، توان کمینه ]25/0P=، 120/0-=[SMD، میانگین توان بی‌هوازی ]13/0P=، 134/0-=[SMD و شاخص خستگی ]56/0P=، 105/0-=[SMD در افراد تمرین‌کرده و ورزشکار تأثیر معناداری ندارد. به‌طورکلی، نتایج فراتحلیل حاضر نشان داد که مکمل‌ حاد آب چغندر هیچ بهبودی درخورتوجهی در شاخص‌های عملکرد بی‌هوازی ارائه نمی‌کند. تحقیقات آینده می‌توانند پتانسیل انرژی‌زایی را با بهینه‌سازی استراتژی مکمل چغندر از نظر دوز مصرفی، مصرف مکمل آب چغندر به شکل‌های مزمن و کوتاه‌مدت بررسی کنند.

https://spj.ssrc.ac.ir/article_4503_09a69de15cf89bc7fe8c0642f906a4dd.pdf

پژوهشگاه تربیت بدنی و علوم ورزشی (وزارت علوم ، تحقیقات و فناوری) فیزیولوژی ورزشی 2322-164X 16 62 2024 06 21 The Effect of Eight Weeks of Home-Based Resistance Training on Melatonin, Serotonin Levels, Sleep Quality, and Quality of Life in Women with Multiple Sclerosis تأثیر هشت هفته تمرینات مقاومتی خانگی بر سطوح ملاتونین، سروتونین، کیفیت خواب و کیفیت زندگی زنان مبتلا به بیماری اِم اِس 105 120 4512 10.22089/spj.2025.16996.2323 FA اشکان گلابی کارشناسی ارشد، گروه فیزیولوژی ورزشی، دانشکده علوم ورزشی، دانشگاه گیلان، رشت ایران، 0009-0007-9110-3521 پیام سعیدی استادیار، گروه فیزیولوژی ورزشی، دانشکده علوم ورزشی، دانشگاه گیلان، رشت ایران، 0000-0001-7325-9484 عالیا صابری استاد، متخصص مغز و اعصاب، استاد دانشگاه علوم پزشکی، دانشگاه علوم پزشکی گیلان، رشت، ایران Journal Article 2024 08 04 Background and Purpose Multiple sclerosis (MS) is an autoimmune and neurodegenerative disease of the central nervous system that causes neurological disability in adults. Around 50% of MS patients experience sleep disorders such as insomnia and restless legs syndrome, which negatively affect their Quality of Life (QoL). Melatonin, a hormone involved in regulating the sleep/wake cycle, is found to be reduced in MS patients. Studies suggest that melatonin supplementation can improve sleep quality and exert antioxidant effects. Additionally, serotonin (5-HT), which is associated with depression and MS, is also reduced in patients. Some antidepressant medications targeting the serotonergic system may help alleviate MS symptoms. Physical activity, such as aerobic and resistance exercises, can help reduce MS symptoms and improve QoL. However, due to limitations such as fatigue and depression, home-based exercise training (HBET) has been proposed as a practical solution. Studies have shown that HBET has positive effects on physical health and QoL in chronic conditions such as Parkinson's disease and type 2 diabetes. However, its effectiveness in MS patients requires further investigation. The present study aims to evaluate the impact of HBET on melatonin and serotonin levels, sleep quality, and QoL in women with MS. Materials and Methods This study was a practical and semi-experimental comparative investigation involving 700 patients with multiple sclerosis (MS) from Gilan University of Medical Sciences' neurology clinic. The sample, determined using G*Power software, included 27 female volunteers aged 25–50, with an expanded disability status scale (EDSS) score between 5–5.5, who met criteria such as no smoking, alcohol use, or comorbid conditions, and a relapsing-remitting MS diagnosis. Participants were randomized into resistance and control groups. Exclusion criteria included inconsistent training attendance or worsening symptoms. Seven participants were excluded due to personal reasons or study protocol non-compliance. The resistance group underwent online training on proper exercise techniques, Borg scale monitoring, and heart rate measurement. They received weighted vests and instructional videos for home-based resistance training (HBRT). The program included 3 weeks of educational sessions followed by an 8-week periodized HBRT protocol divided into hypertrophy (4 weeks) and strength (4 weeks) phases. Training intensity was tailored individually using weights, fatigue levels, heart rate, and clinical conditions under physician supervision. Each session included warm-ups, 25–30 minutes of resistance exercises, and cool-downs, with rest intervals of 2–4 minutes. The control group did not engage in any specific activity. Blood samples were collected pre- and post-intervention after overnight fasting. Physical assessments (e.g., height, weight, WHR, body fat, blood pressure) were conducted at participants' homes. Sleep quality and QoL were measured using validated questionnaires. Sleep metrics included subjective sleep quality, sleep duration, disturbances, medication use, and daytime dysfunction. QoL evaluation encompassed physical function, emotional role, energy, social function, pain, and general health. Data were analyzed using descriptive and inferential statistics (Shapiro-Wilk test, ANCOVA, paired t-test) in SPSS 26, with significance set at P≤0.05. Serum melatonin and serotonin levels were measured via ELISA using Elabscience kits. Feedback was collected after each session for protocol adherence, and weights were adjusted biweekly during home visits to ensure progression. The results were intended to evaluate the effects of HBRT on sleep, QoL, and biomarkers in MS patients. Findings The results of the ANCOVA test showed no significant differences in serotonin levels (F=0.05, P=0.827) and melatonin levels (F=0.132, P=0.722) between the two groups. A significant difference was observed only in the subscale of sleep medication use, while no significant differences were found in other sleep quality subscales (P>0.05). The results related to the QoL subscales, indicate that there were no significant differences between the resistance and control groups in any of the QoL subscales (P>0.05). Conclusion This study examined the effects of eight weeks of home-based resistance training on serum levels of melatonin and serotonin, sleep quality, and QoL in women with MS. The results showed no significant effects of the training on these parameters, which contrasts with previous studies such as those by Deichmann et al. (2021) and Shobeiri et al. (2022). The difference in intervention type may explain this discrepancy, as previous research mainly focused on aerobic exercise, which has been shown to increase serotonin and brain-derived neurotrophic factor (BDNF) levels. Serotonin plays a crucial role in regulating inflammation and providing neuroprotective effects in MS. Exercise may help reduce inflammation by decreasing fat mass and increasing regulatory T cells. However, in the present study, no significant changes in melatonin levels were observed. Limited research exists on the impact of resistance training on melatonin in MS patients, but some studies have shown that melatonin supplementation can improve sleep quality. The lack of improvement in sleep quality in this study may be due to methodological limitations, such as self-reporting. More objective tools, such as actigraphy, may provide better insights. Additionally, factors like patients' disability levels, fatigue, and the use of immunomodulatory drugs may influence the effects of exercise on melatonin levels. Home-based training has limitations such as fear of health deterioration, lack of motivation, and safety concerns, whereas supervised group training may overcome these barriers. Overall, the findings suggest that home-based resistance training does not significantly improve hormonal levels, sleep quality, or QoL in MS patients. Article Message It seems that performing exercises without direct supervision for at least 8 weeks in MS patients will lack the spectator effect and motivation necessary for their effectiveness. Funding This study received no funding from public, commercial, or nonprofit organizations. Authors’ Contributions Contribution to writing and editing: Payam Saidie, Ashkan Golabi; Patient selection and assessment: Alia Saberi, Payam Saidie, Ashkan Golabi; Monitoring and collection of data: Ashkan Golabi, Payam Saidie, Alia Saberi; Statistical analysis: Payam Saidie; Supervision: Payam Saidie, data interpretation: payam saidie, Alia Saberi, Ashkan Golabi. Ethical Considerations The present study has been reviewed and approved by the Institute of Physical Education and Sport Sciences under the ethics code SSRI.REC-2106-1085 (R2). Conflicts of Interest The authors declared no conflict of interest. Acknowledgement The authors would like to express their gratitude to the director of the Besat Neurology Clinic of Rasht University of Medical Sciences and all the participants. مولتیپل اسکلروزیس (MS) یک اختلال مزمن، پیش‌رونده و با واسطه ایمنی است که بر سیستم عصبی مرکزی تأثیر می‌گذارد و شایع‌ترین علت ناتوانی عصبی غیرتروماتیک در بزرگسالان است. هدف مطالعه حاضر، بررسی تأثیر هشت هفته تمرینات مقاومتی خانگی بر سطوح سرتونین، ملاتونین، کیفیت خواب و کیفیت زندگی در زنان مبتلا به بیماری MS بود. تعداد 27 بیمار زن (66/2 ± 56/34) مبتلا به MS از نوع عودکننده-فروکش‌کننده با امتیاز EDSS بین صفر تا 5/5 از مراجعه‌کنندگان به درمانگاه نورولوژی دانشگاه علوم پزشکی گیلان، به دو گروه تمرینات مقاومتی و گروه کنترل تقسیم شدند. برنامه تمرینات مقاومتی هشت هفته فعالیت ورزشی در منزل شامل چهار هفته فاز هایپرتروفی و چهار هفته فاز قدرت بود. کیفیت خواب و زندگی به ترتیب توسط پرسشنامه کیفیت خواب و پرسشنامه 26 سؤالی کیفیت زندگی سازمان جهانی بهداشت ارزیابی شد. همچنین سطوح ملاتونین و سرتونین سرمی قبل و بعد دوره تمرین با استفاده از روش الایزا ارزیابی شد. داده مطالعه در سطح 05/0 با استفاده از روش آماری کوواریانس بررسی شد. بررسیها نشان داد که سطوح ملاتونین، سرتونین و کیفیت زندگی و کیفیت خواب طی هشت هفته تمرینات مقاومتی تغییر معناداری نداشت (05/0<P). این نتایج نشان داد که تمرینات مقاومتی باعث بهبود سطوح ملاتونین یا کیفیت خواب در بیماران MS نمی‌شود. به نظر میرسد، اجرای تمرینات بدون نظارت مستقیم فاقد اثر تماشاگر و انگیزه لازم برای اثربخشی آن‌ها خواهد بود.

https://spj.ssrc.ac.ir/article_4512_63c4b1baf3b4460fa9936b1a20919bec.pdf

پژوهشگاه تربیت بدنی و علوم ورزشی (وزارت علوم ، تحقیقات و فناوری) فیزیولوژی ورزشی 2322-164X 16 62 2024 06 21 The Effects of Different Protocols of Plyometric Exercises as Post-Activation Potentiation on Power Performance in Athletes: A Systematic Review on PAP Studies تأثیر پروتکلهای مختلف حرکات پلایومتریک به‌عنوان ظرفیت‌سازی پس‌فعالی روی عملکرد توانی ورزشکاران: مروری نظام‌مند بر مطالعات ظرفیت‌سازی پس‌فعالی 122 138 4628 10.22089/spj.2025.16807.2315 FA ایمان نیرومند دانشجوی کارشناسی ارشد فیزیولوژی ورزشی، دانشکده علوم ورزشی، دانشگاه خوارزمی، تهران، ایران 0009-0006-4232-7767 حمید رجبی استاد فیزیولوژی ورزشی، دانشکده علوم ورزشی، دانشگاه خوارزمی، تهران، ایران 0000-0002-3276-1598 صادق امانی استادیار فیزیولوژی ورزشی، دانشکده علوم ورزشی، دانشگاه خوارزمی، تهران، ایران 0000-0002-3021-8970 Journal Article 2024 05 31 Background and Purpose Enhancing muscular power capacity in competitive sports that require strength, power, and speed is of great importance. Research has shown that warming up using post-activation potentiation (PAP) can significantly improve athletic performance. Unlike traditional warm-ups, which involve low-intensity aerobic movements and stretching, the PAP method employs maximum or near-maximum intensity speed, plyometric, or resistance exercises. The mechanisms behind PAP include improved neural conduction, increased motor unit recruitment, reduced synaptic inhibition, and mechanical adaptations such as optimized muscle-tendon junction angles. These neuromuscular adaptations are particularly effective in explosive movements like jumping and throwing. Among PAP implementation methods, plyometric exercises are considered a practical and efficient option due to their lack of special equipment requirements, lower fatigue induction, and activation of fast-twitch motor units. However, research findings in this area are inconsistent. Some studies confirm performance improvements, while others report fatigue or no significant effects due to inappropriate exercise volume or intensity. For example, high-volume exercises (such as 70 seconds of continuous tension) may lead to fatigue, whereas protocols with higher repetitions (e.g., 20 jumps) have shown favorable results. This study systematically reviews existing research to examine the variables of volume, intensity, and rest intervals in plyometric exercises, aiming to determine the optimal combination for enhancing power performance. The ultimate goal is to provide practical strategies for designing effective warm-up protocols in strength-speed sports. Methods & Materials This systematic review examined research articles published in English between 2007 and 2023, sourced from Scopus, Web of Science, and PubMed up to August 2023, using keywords such as "post activation potentiation," "PAP," and "muscle power." Only peer-reviewed journal articles were included, excluding conference abstracts. Additional manual searches on Google Scholar ensured no relevant studies were missed. Inclusion criteria required participants aged 18–35 with at least two years of training, excluding studies using electrical stimulation or isokinetic dynamometers, and focusing on explosive power performance (e.g., jumps, throws). Two researchers independently extracted and coded data, categorizing plyometric exercises by volume (>20 or <20 reps), intensity (bodyweight-only vs. weighted), and rest intervals (<5 min, 5–10 min, >10 min) between conditioning and main activities. From 1,974 initially identified studies, 20 duplicates and 1,856 irrelevant studies were excluded, leaving 98 for full-text screening, with 24 meeting final eligibility criteria. Findings After an initial screening of 1,974 identified studies, duplicate and irrelevant articles were removed, leaving 98 studies for full-text evaluation. Ultimately, 24 eligible studies meeting the inclusion criteria—participants aged 18–35 years, at least two years of training experience, no use of electrical stimulation or isokinetic dynamometer devices, and assessment of explosive power movements—were analyzed. These studies, published between 2007 and 2021, included a total of 309 participants, with sample sizes ranging from 5 to 34 individuals. The findings revealed that a post-activation potentiation (PAP)-based warm-up protocol using plyometric exercises could enhance athletes' performance if three key factors were considered. First, regarding exercise volume, performing movements with fewer than 20 repetitions demonstrated more positive effects compared to higher repetitions. Second, in terms of exercise intensity, bodyweight plyometric exercises (without additional resistance) were sufficient to induce adequate stimulation and improve power performance. Third, concerning rest intervals, a recovery period of less than 5 minutes between plyometric exercises and the main activity had the most beneficial impact on athletic performance. Conclusion This systematic review examined the impact of plyometric exercises used for post-activation potentiation (PAP) on athletes' explosive power performance (e.g., vertical jump height, discus/hammer throw distance). The analysis included 24 studies (309 participants), focusing on competitive athletes with at least two years of training experience. Key findings highlighted the influence of exercise volume, intensity, and rest intervals on PAP effectiveness. Low-volume plyometrics (<20 reps) as a conditioning activity (CA) enhanced power performance more than high-volume protocols. Excessive repetitions (>20) led to fatigue (e.g., phosphagen depletion, hydrogen ion accumulation), masking PAP benefits. Studies suggest that <10 seconds of tension per set optimizes PAP, whereas prolonged efforts (>70 seconds) impair performance. Bodyweight plyometrics (no external load) consistently improved power output. Adding resistance reduced movement velocity (inverse force-velocity relationship) and increased fatigue, diminishing PAP effects. Dynamic contractions in plyometrics may preferentially recruit high-threshold motor units, but excessive loading risks muscle damage (e.g., Z-line disruption) and central fatigue. A 5-minute rest between plyometrics and the main activity balanced PAP potentiation and fatigue recovery. Shorter rests (<5 min) favored fatigue, while longer rests (>10 min) diminished PAP effects. Unlike heavy resistance training, plyometrics induced faster metabolic recovery (e.g., lactate clearance), justifying shorter rest periods. Athlete fitness level may further modulate optimal recovery timing. Several limitations warrant consideration when interpreting these findings. The inherent heterogeneity in plyometric exercise selection across studies - encompassing variations in jump types, contact surfaces, and movement amplitudes - introduces some degree of programming ambiguity. Additionally, the reviewed literature demonstrates relative paucity in addressing potential individual response variability based on training status, fiber type distribution, or sex-specific considerations. These areas represent valuable targets for future investigative efforts. In summary, the preponderance of evidence supports the implementation of plyometric-based PAP protocols characterized by restrained volume (below twenty repetitions), bodyweight resistance, and five-minute recovery intervals as a reliable means of enhancing acute power performance. These findings provide sports practitioners with an evidence-based framework for optimizing warm-up strategies in power-dependent disciplines, while simultaneously highlighting important avenues for continued research into individualized protocol refinement. The consistent demonstration of performance enhancements across diverse athletic populations underscores the practical value of these recommendations for competitive training environments. Article Message Preparatory activities used as warm-up protocols in major athletic events to prime the neuromuscular and skeletal systems for optimal explosive performance should be carefully and intelligently selected. Among various speed and strength exercises, plyometric movements are likely a safer option for muscle potentiation. Additionally, these movements require less equipment and space compared to traditional strength and speed exercises. Once plyometric exercises are chosen as a preparatory activity, it is advisable to perform them with fewer than 20 repetitions using body weight only. Moreover, a rest period of approximately 5 minutes after these exercises is likely sufficient for muscle potentiation. Acknowledgments We would like to express our sincere gratitude to all those who contributed to and supported this study. Conflict of Interest The authors declare that they have no conflict of interest in writing this article. رسیدن به حداکثر توان عضلانی برای اجرای بهترین عملکرد توانی و سرعتی در بسیاری از رویدادهای ورزشی مهم است. نشان داده شده است که ظرفیت‌سازی پس‌فعالی (PAP) در حین گرم‌کردن مناسب، توان و سرعت ورزشکار را افزایش می‌دهد؛ البته میزان تأثیر فعالیت آماده‌ساز، به پروتکل شدت و حجم آن حرکت و همچنین فاصله استراحت بین آن حرکت و اجرای فعالیت اصلی بستگی دارد. این مطالعه مروری نظام‌مند، تأثیر پروتکل‌های مختلف از نظر حجم، شدت و زمان استراحت بعد از انجام تمرین پلایومتریک را به‌عنوان یک فعالیت آماده‌ساز (CA) بر عملکرد توان ورزشکاران بررسی کرده است. این مطالعه از تمام اصول بررسی‌های مطالعه مروری نظام‌مند پیروی کرده است. معیارهای واجد شرایط شامل مطالعات متقاطع، تصادفی، غیرتصادفی و متوازن بودند که اثرات ظرفیت‌سازی پس‌فعالی داوطلبانه ناشی از فعالیت پلایومتریک را بر عملکرد توان مشاهده کردند و متغیرهای تمرینی حجم، شدت و زمان استراحت از فعالیت آماده‌ساز تا فعالیت اصلی را گزارش کردند. تجزیه و تحلیل روی 24 مطالعه در پایگاه‌های Scopus، Web of Science و PubMed تا ماه آگوست سال 2023 صورت گرفت که توسط دو محقق به‌طور جداگانه انتخاب شدند. روش تجزیه و تحلیل، استخراج متغیرهای تمرین پلایومتریک (حجم، شدت و فاصله استراحت) از هر مطالعه و مقایسه آن‌ها در ارتباط با رسیدن به ظرفیت‌سازی پس‌فعالی، خستگی یا اثر خنثی بود. این مطالعه مروری نظام‌مند نشان داد که داشتن پروتکل گرم‌کردن ظرفیت‌سازی پس‌فعالی که با استفاده از حرکات پلایومتریک انجام شود، اثرات مثبت بر عملکرد توانی ورزشکاران ایجاد می‌کند. همچنین تمرین پلایومتریک به‌عنوان PAP زمانی که با حجم کم (<20 تکرار) و تنها با وزن بدن (مقاومت کم) انجام شود و پس از آن و قبل از انجام حرکت اصلی تا 5 دقیقه استراحت وجود داشته باشد، تأثیر مثبت بیشتر و مطمئن‌تری بر عملکرد توانی ورزشکاران مشاهده می‌شود؛ بنابراین به ورزشکاران توانی پیشنهاد می‌شود که از حرکات پلایومتریک کم‌حجم و با وزن بدن که حدود 5 دقیقه استراحت تا فعالیت اصلی داشته باشد، به‌عنوان فعالیت آماده‌ساز استفاده کنند.

https://spj.ssrc.ac.ir/article_4628_73634c1dcbe056c1f7dcf5969da406c8.pdf