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1.
Normativne vrednosti bojno-kondicijskega testa pripadnikov Slovenske vojske glede na starost in spol
Boštjan Šimunič, 2025, samostojni znanstveni sestavek ali poglavje v monografski publikaciji

Povzetek: Vojaki se pri svojem delu srečujejo z različnimi opravili, med njimi tudi težjimi oziroma kompleksnimi, ki so že sama po sebi dejavnik tveganja za zdravje in tudi poškodbe. Zato je izjemno pomembno, da imajo optimizirane notranje dejavnike tveganja, kot je telesna pripravljenost, predvsem specifična telesna pripravljenost, vezana na izvajanje temeljnih, tudi bojnih opravil. Zato smo validirali nov bojnokondicijski test (BKT) telesne in bojne pripravljenosti pripadnikov in pripadnic SV različne starosti. Zasnovali smo BKT, ki je bil usmerjen v vrednotenje telesnih sposobnosti in bojne učinkovitosti delovanja pripadnikov SV, predvsem logistično podporo bojnim enotam. BKT je opravilo 752 pripadnikov in 100 pripadnic SV avgusta/septembra 2022. Pri tem nismo zabeležili nobene poškodbe. Merili smo čas dokončanja BKT ter analizirali povprečne vrednosti, 5., 10., 20., 30., 40., 60., 70., 80., 90. in 95. percentil, ločeno po spolu ter starostnih razredih 20–30 let, 30–40 let, 40–50 let in nad 50 let. Ugotovili smo, da se moškim s starostjo podaljšuje čas BKT in tudi njegova variabilnost. Ženske dosegajo od starosti neodvisne rezultate, variabilnost rezultatov pa se s starostjo zmanjšuje. Predlagali smo interpretacijo doseženega rezultata v eno izmed kategorij: zelo slabo, slabo, povprečno, dobro in odlično. BKT je preprost in veljaven test telesne in bojne pripravljenosti za oba spola ter vse starostne skupine pripadnikov in pripadnic SV.
Ključne besede: bojno-kondicijski testi, pripravljenost, vzdržljivost, normativne vrednosti, zdravje, poškodbe
Objavljeno v DiRROS: 19.05.2025; Ogledov: 154; Prenosov: 70
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2.
Twenty-one days of bed rest alter motor unit properties and neuromuscular junction transmission in young adults
Fabio Sarto, Miloš Kalc, Evgeniia Motanova, Martino V. Franchi, Daniel W Stashuk, Nina Murks, Giacomo Valli, Samuele Negro, Tomaž Prašnikar, Mladen Gasparini, Giovanni Martino, Giuseppe De Vito, Aleš Holobar, Boštjan Šimunič, Rado Pišot, Marco Vincenzo Narici, 2025, izvirni znanstveni članek

Povzetek: Previous studies showed that properties of higher‐threshold motor units (MUs) and neuromuscular junction (NMJ) function are preserved during short‐term disuse. This study aimed to test how a longer disuse period affects MU properties, NMJ transmission, and NMJ morphology remodeling. Nine young healthy males (age: 18‐29 years) underwent 21 days of horizontal bed rest. Pre‐ (BR0) and post‐bed rest (BR21), quadriceps maximal voluntary contraction (MVC), and size were assessed. We combined intramuscular electromyography (iEMG) and high‐density surface electromyography (HDsEMG) recordings on the vastus lateralis to assess MU properties at 25% and 50% of MVC. Muscle biopsies and blood samples were also collected. Quadriceps MVC and size decreased at BR21. We found alterations in MU properties at both contraction intensities, including reduced discharge rate, MU potential area changes, and increased complexity. NMJ transmission was found to be reduced at BR21 at 25% MVC. This functional NMJ impairment was biochemically corroborated by an increase in serum C‐terminal agrin fragment concentration, a biomarker of NMJ instability. In addition, a direct assessment of NMJ morphology revealed the presence of some denervated NMJs exclusively at BR21. In conclusion, 21‐day bed rest altered MU properties across different contraction intensities and impaired NMJ transmission with initial signs of remodeling/denervation. Disuse duration appears to be a critical factor, as previous shorter studies failed to detect some of these changes. We believe these findings are clinically relevant for disuse after trauma, surgery, or illness, and may support the development of effective countermeasures.
Ključne besede: disuse, unloading, physical inactivity, electrophysiology, electromyography
Objavljeno v DiRROS: 13.05.2025; Ogledov: 226; Prenosov: 69
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3.
Mitochondrial sensitivity to submaximal [ADP] following bed rest : a novel two-phase approach associated with fibre types
Lucrezia Zuccarelli, Maria De Martino, Antonio Filippi, Alice E. Knapton, Benjamin D. Thackray, Giovanni Baldassarre, Boštjan Šimunič, Rado Pišot, Giuseppe Sirago, Elena Monti, Marco Vincenzo Narici, Miriam Isola, Andrew J. Murray, Giovanna Lippe, Bruno Grassi, 2025, izvirni znanstveni članek

Povzetek: Background: We recently demonstrated that following a 10-day exposure to inactivity/simulated microgravity impairments ofoxidative metabolism were located ‘upstream’ of mitochondrial function, as evaluated by maximal ADP-stimulated mitochon-drial respiration (JO 2max) determined ex vivo. The aim of this study was to evaluate mitochondrial sensitivity to submaximal[ADP] by an alternative approach aimed at identifying responses associated with fibre type composition.Methods: Isolated permeabilized vastus lateralis fibres were analysed by high-resolution respirometry in 9 young males beforeand after a 10-day horizontal bed rest. Eleven submaximal titrations of ADP (from 12.5 to 10 000 μM) were utilized to assess com-plex I + II-linked ADP sensitivity. We applied to JO 2 versus [ADP] data a traditional Michaelis–Menten kinetics equation, withthe calculation of the apparent K m and maximal respiration (Vmax), and two ‘sequential’ hyperbolic equations, yielding two K mand Vmax values. The two-hyperbolic equations were solved and the [ADP] value corresponding to 50% of JO 2max was calculated.Isoform expression of myosin heavy chains (MyHC) 1, 2A and 2X was also determined. Control experiments were also carriedout on rat skeletal muscle samples with different percentages of MyHC isoforms.Results: The two hyperbolic equations provided an alternative fitting of data and identified two distinct phases of the JO 2 versus[ADP] response: a first phase characterized by low Vmax (Vmax1 , 28 ± 10 pmol s−1 mg−1) and apparent K m (K m1 , 62 ± 54 μM) anda second phase characterized by higher Vmax (Vmax2 , 61 ± 16 pmol s−1 mg−1) and K m (K m2 , 1784 ± 833 μM). Data were confirmedin control experiments carried out in rat muscle samples with different percentages of MyHC isoforms. Correlation and receiveroperating characteristics analyses suggest that the two phases of the response were related to the % of MyHC isoforms.Conclusions: A novel mathematical approach (two sequential hyperbolic functions) for the fitting of JO 2 versus [ADP] data ob-tained by high-resolution respirometry on permeabilized skeletal muscle fibres, obtained in humans and rats, provided an alter-native fitting of the experimental data compared to the traditional Michaelis–Menten kinetics equation. This alternative modelallowed the identification of two distinct phases in the responses, which were related to fibre type composition. A first phase, characterized by low apparent K m and Vmax values, was correlated with the percentage of less oxidative (Type 2A + 2X) MyHCisoforms. A second phase, characterized by high apparent K m and Vmax , was related to more oxidative (Type 1) MyHC isoforms.
Ključne besede: ADP, bed rest, mitochondrial sensitivity, myosin heavy chains, skeletal muscle mitochondria
Objavljeno v DiRROS: 05.05.2025; Ogledov: 220; Prenosov: 82
.pdf Celotno besedilo (3,59 MB)
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4.
Neuromuscular junction instability with inactivity : morphological and functional changes after 10 days of bed rest in older adults
Stefano Schiaffino, Evgeniia Motanova, Fabio Sarto, Samuele Negro, Marco Pirazzini, Ornella Rossetto, Michela Rigoni, Daniel W Stashuk, Mladen Gasparini, Boštjan Šimunič, Rado Pišot, Marco Vincenzo Narici, 2025, izvirni znanstveni članek

Povzetek: The neuromuscular junction (NMJ) plays a key role in modulating muscle contraction,but the impact of short-term disuse on NMJ structure and function, particularly in older humans,remains unclear. This study aimed to investigate NMJ alterations following 10 days of horizontalbed rest in 10 older males (68.5 ± 2.6 years). Before and after bed rest, vastus lateralis musclebiopsies were obtained to evaluate NMJ morphology, intramuscular EMG (iEMG) was recordedto assess NMJ function and blood samples were collected to determine circulating C-terminal agrinfragment (CAF) concentration, a biomarker of NMJ remodelling. In a sub-cohort of six participantswho had NMJs in both pre- and post-bed rest biopsies, we observed altered NMJ morphology,including reduced overlap between NMJ terminals, as well as increased endplate area and peri-meter. CAF concentration was elevated after bed rest, suggesting ongoing NMJ remodelling. iEMGanalysis showed increased motor unit potential complexity and reduced firing rate. In addition,we observed impaired NMJ transmission, inferred from increased near-fibre jiggle and segmentjitter. These findings suggest that older male individuals are susceptible to NMJ remodelling andimpaired transmission with short-term disuse, providing valuable insights into the morphologicaland functional consequences of inactivity in an ageing population. Our study highlights theimportance of developing interventions for mitigating the detrimental consequences of inactivityon neuromuscular health in older adults, which they frequently experience following injury, trauma,illness or surgery.
Ključne besede: ageing, C-terminal agrin, fragment disuse, electromyography, motor unit, NMJ unloading
Objavljeno v DiRROS: 19.03.2025; Ogledov: 286; Prenosov: 229
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5.
20 years of kinesiology research for quality of life
Rado Pišot, Boštjan Šimunič, 2024, predgovor, uvodnik, spremna beseda

Ključne besede: sports, kinesiology, health benefits, physical activity
Objavljeno v DiRROS: 13.03.2025; Ogledov: 217; Prenosov: 109
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6.
Prevalence of sarcopenia among Slovenian older adults and associated risk factors
Katarina Puš, Saša Pišot, Uroš Marušič, Manca Peskar, Kaja Teraž, Miloš Kalc, Helena Blažun Vošner, Peter Kokol, Jernej Završnik, Boštjan Šimunič, 2025, izvirni znanstveni članek

Povzetek: Introduction: Sarcopenia is a multifaceted condition affecting between 10 and 16% of the global population, and although multiple classification algorithms exist, no prevalence has been reported for a representative sample of the Slovenian population. Furthermore, multiple behavioural factors, such as malnutrition, physical inactivity, sedentary lifestyle and lower cognitive function, can contribute to the risk of sarcopenia. This study aims to: a) determine sarcopenia prevalence among Slovenian older adults according to different classification algorithms, b) compare the agreement among the algorithms and c) evaluate the relationship between proposed risk factors and sarcopenia. Methods: 654 participants (≥60 years, 30.4% males) have been classified into sarcopenia groups according to eight algorithms, and agreement (Fleiss K) between them was calculated. Additionally, age, sex, nutritional status, physical activity, sedentary levels and cognitive function were assessed as sarcopenia risk/protective factors. Results: The prevalence of sarcopenia according to EWGSOP2 was 4.1%, ranging from 2.1% to 15.3%, when classified by all eight algorithms. Overall agreement between algorithms was weak (K=.429; 95% CI .414 to .444) with 0.6% of participants classified as sarcopenic by all eight algorithms. Adequate nutrition and physical activity were identified as protective factors, while age, lower cognitive function and sedentary lifestyle were considered risk factors. Conclusion: Sarcopenia prevalence among the Slovenian general population was lower than in the global population. We can conclude that different sarcopenia algorithms lead to a different prevalence of sarcopenia. It is of great importance to be cautious when comparing prevalences among studies and to further validate the classification algorithms.
Ključne besede: sarcopenia, prevalence, epidemiology, classification algorithms, risk factors
Objavljeno v DiRROS: 03.03.2025; Ogledov: 247; Prenosov: 120
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7.
Frequency of physical activity-related injuries among adolescents : an umbrella review
Kerrtu Toivo, Peter Bakalár, Mari Leppänen, Jari Parkkari, Ensar Abazović, Boštjan Šimunič, Kaja Teraž, Marta Malinowska-Cieślik, Jaroslava Kopčáková, Aurel Zelko, Agnieszka Michalska, Dagmar Sigmundova, Rado Pišot, Armin Paravlić, 2025, pregledni znanstveni članek

Povzetek: Objectives: The aim of this umbrella review was to investigate the frequency of physical activity-related injuries (PARI) among adolescents. Our secondary objective was to describe the available reviews of injuries in three settings: organized sports, leisure time physical activity (PA), and school physical education (PE). Methods: We conducted an overview of reviews consistent with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement guidelines on the frequency of physical activity related injuries in adolescents. Results: We identified 19 systematic reviews with at least moderate quality to include in the review. We were not able to pool data from reviews and conduct meta-analysis due to heterogeneity of injury definitions, exposure times, and sample demographics. All reviews included studies of injuries sustained in organized sports, and injury incidence was higher during matches than training. No systematic reviews were found focusing on leisure time or school-based PA injuries. Conclusion: High-quality research is essential to understand the frequency of various types of physical activity related injuries among adolescents in organized sports, PE, and leisure time activities to develop more effective prevention strategies.
Ključne besede: physical activity-related injuries, sports injuries, adolescence, frequency, prevalence, incidence
Objavljeno v DiRROS: 22.01.2025; Ogledov: 319; Prenosov: 183
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8.
Initial glutathione depletion during short-term bed rest : pinpointing synthesis and degradation checkpoints in the γ-glutamyl cycle
Filippo Giorgio Di Girolamo, Filippo Mearelli, Mariella Sturma, Nicola Fiotti, Kaja Teraž, Alja Ivetac, Alessio Nunnari, Pierandrea Vinci, Boštjan Šimunič, Rado Pišot, Gianni Biolo, 2024, izvirni znanstveni članek

Povzetek: Hypokinesia triggers oxidative stress and accelerates the turnover of the glutathione system via the γ-glutamyl cycle. Our study aimed to identify the regulatory checkpoints controlling intracellular glutathione levels. We measured the intermediate substrates of the γ-glutamyl cycle in erythrocytes from 19 healthy young male volunteers before and during a 10-day experimental bed rest. Additionally, we tracked changes in glutathione levels and specific metabolite ratios up to 21 days of bed rest. Using gas chromatography-mass spectrometry and the internal standard technique, we observed a 9 ± 9% decrease in glutathione levels during the first 5 days of bed rest, followed by an 11 ± 9% increase from the 5th to the 10th day, nearly returning to baseline ambulatory levels. The cysteinyl-glycine-to-glutathione ratio, reflecting γ-glutamyl cyclotransferase activity (a key enzyme in glutathione breakdown), rose by 14 ± 22% in the first 5 days and then fell by 10 ± 14% over the subsequent 5 days, again approaching baseline levels. Additionally, the γ-glutamyl cysteine-to-cysteine ratio, indicative of γ-glutamyl cysteine synthetase activity (crucial for glutathione synthesis), increased by 12 ± 30% on day 5 and by 29 ± 41% on day 10 of bed rest. The results observed on day 21 of bed rest confirm those seen on day 10. By calculating the ratio of product concentration to precursor concentration, we assessed the efficiency of these key enzymes in glutathione turnover. These results were corroborated by directly measuring glutathione synthesis and degradation rates in vivo using stable isotope techniques. Our findings reveal significant changes in glutathione kinetics during the initial days of bed rest and identify potential therapeutic targets for maintaining glutathione levels.
Ključne besede: antioxidant, muscle unloading, glutathion turnover, γ-glutamyl cycle, gamma-glutamyl cycle
Objavljeno v DiRROS: 21.11.2024; Ogledov: 388; Prenosov: 1281
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9.
The effectiveness of neuromuscular training warm-up program for injury preventionin adolescent male basketball players
Armin Paravlić, Peter Bakalár, Katarina Puš, Saša Pišot, Miloš Kalc, Kaja Teraž, Luka Šlosar, Manca Peskar, Uroš Marušič, Boštjan Šimunič, 2024, izvirni znanstveni članek

Povzetek: This study evaluated the effects of a neuromuscular training (NMT) warm-up program on injury incidence,neuromuscular function, and program adherence, maintenance and acceptance in adolescent basketballplayers. A total of 275 players from 20 Slovenian teams (15 ± 1.7 years of age), were randomized into anintervention group (IG, n=129) and a control group (CG, n=146). Over three months, the IG incorporatedNMT into their warm-ups, while the CG followed their usual practice. Measurements of body anthro-pometry, muscle contractile properties, and balance were taken before and after the intervention. Also,the injury incidence, training adherence and maintenance were reported. Both groups showed improvedbalance, with no significant difference between them. However, IG demonstrated reduced delay times inspecific muscles, indicating improved neuromuscular function. Injury prevalence proportion (%) duringthe whole study period was higher in the control group compared to intervention (IG: 10.9% vs. CG:23.3%), and incidence rate. Moreover, the incidence rate ratio for sustaining an injury was 2.6 on average(ranging from 0.88 to 7.07 for tendon and muscle injuries, respectively), indicating significantly lowerinjury risk in IG than CG. These findings highlight the effectiveness of NMT warm-ups in reducing injuryrisk and enhancing neuromuscular function, emphasizing the value of structured injury preventionstrategies in youth sports.
Ključne besede: muscle contractile properties, balance, injury prevalence, training adherence
Objavljeno v DiRROS: 18.11.2024; Ogledov: 448; Prenosov: 223
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10.
Conference report : 2024 Padua - 5 days on muscle and mobility medicine (2024PDM3)
Kaja Teraž, Boštjan Šimunič, 2024, drugi sestavni deli

Ključne besede: skeletal muscle, conference, reports
Objavljeno v DiRROS: 28.10.2024; Ogledov: 371; Prenosov: 198
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