1. Changes in gait and postural control after 10-day bed rest and 30-day recovery : Elektronski virLuka Šlosar, Manca Peskar, Boštjan Šimunič, Rado Pišot, Marco Vincenzo Narici, Uroš Marušič, 2026, izvirni znanstveni članek Povzetek: Background Prolonged bed rest is a well-established model for studying the effects of immobility on functional performance, especially gait and postural control. Understanding how these functions deteriorate and recover across age groups is essential for developing targeted rehabilitation strategies. Research question How does a 10-day horizontal bed rest affect gait performance and postural control in young and older adults, and to what extent do these effects differ by age? Methods Following a multistage screening process from a large pool of healthy male volunteers, ten older men (68.5 ± 2.6 years) and ten young men (22.9 ± 4.7 years) completed 10 days of horizontal bed rest in a controlled laboratory setting, followed by a standardized 30-day recovery program. Postural control and gait speed assessed under self-selected and brisk walking conditions were measured before bed rest, immediately after, and following a 30-day recovery program. Results Following bed rest, self-selected walking speed did not differ significantly from baseline in either group. In contrast, brisk walking speed significantly decreased in older (−11.4%, p < 0.05) and young adults (−9.9%, p < 0.05), with both groups returning to baseline values after recovery. Postural control deteriorated significantly in older adults (-15.5%), whereas no significant difference from baseline was observed in young adults. After baseline adjustment, postural control showed a significant group effect both after bed rest (η² > 0.244) and post-recovery (η² > 0.395). Significance The findings reveal clear age-related differences in responses to inactivity and recovery. Older adults experienced greater impairments and slower restoration of balance, indicating heightened vulnerability to functional decline during periods of immobilization. These findings underscore the age-dependent impact of bed rest and the importance of tailored rehabilitation strategies.
Ključne besede: aging, physical inactivity, mobile body imaging, functional decline
Objavljeno v DiRROS: 24.04.2026; Ogledov: 125; Prenosov: 106
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2. Mental - and temporal - demand NASA - task load Index scores correlate with decreases in irisin serum levels in healthy individuals subjected to 10-day bed restPatrizia Pignataro, Uroš Marušič, Roberta Zerlotin, Angela Oranger, Manuela Dicarlo, Clelia Suriano, Paolo Taurisano, Rado Pišot, Boštjan Šimunič, Marco Vincenzo Narici, 2026, izvirni znanstveni članek Povzetek: Background Bed rest (BR) is a widely used analogue of space flight that aims to replicate microgravity conditions, such as immobilization and a lack of sensorimotor stimuli. In a previous BR study, we evaluated the changes in irisin serum levels, a myokine produced mainly by skeletal muscle that exerts pleiotropic effects on several organs, including the brain. Objective Here, we evaluated whether the decline in circulating irisin concentrations during 10 days of horizontal BR correlated with the National Aeronautics and Space Administration Task Load Index (NASA-TLX). Methods NASA-TLX was obtained from young healthy participants at the end of the BR protocol. It is a self-report measure of task load that includes six subscales: mental demand, physical demand, temporal demand, performance, effort, and frustration. Each subscale score was correlated with the decline in serum irisin levels measured while participants were supine. Irisin decline was calculated as the difference between levels on the first day of BR (BR0) and the last day (BR9). Results Our results show a significant positive correlation between irisin decline and both mental demand and temporal demand, whereas correlations with the remaining subscales showed a positive association with irisin decline but did not reach statistical significance. Conclusion These findings suggest that reduced irisin levels are associated with increased perceived mental demand and time pressure (temporal demand) during BR. Because temporal demand can exacerbate high mental activity in a state of cognitive overload, maintaining higher circulating irisin levels could represent an effective countermeasure to improve the cognitive performance of participants during future BR studies and may help astronauts manage mental and temporal pressure during space missions.
Ključne besede: bed rest, microgravity, irisin, cognitive performance, NASA-TLX indeks
Objavljeno v DiRROS: 09.04.2026; Ogledov: 134; Prenosov: 83
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3. The application of ultrasound sarcopenia index in sarcopenic populationKatarina Puš, Fabio Sarto, Marco Vincenzo Narici, Boštjan Šimunič, 2026, izvirni znanstveni članek Povzetek: Background: Aging leads to progressive motor system decline, which can result in sarcopenia, defined as the age- related loss of muscle mass and function. Architectural changes, epitomized by a decrease in fascicle length (Lf) and muscle thickness (MT), provide a useful signature of sarcopenia. Their ratio (Lf/MT), named ultrasound sarcopenia index (USI), is a new parameter proposed for evaluating changes in muscle geometric proportions associated with muscle atrophy but lacks application in a sarcopenic population. This study aimed to explore vastus lateralis USI in a sarcopenic population. Methods: In a sample of 139 older adults (54% females), recruited from Italy and Slovenia, we assessed muscle architecture using ultrasound imaging to measure Lf, MT, pennation angle (PA), and USI. We assessed handgrip strength, sit-to-stand test, and physical performance with timed up-and-go and gait speed. Appendicular lean mass was assessed with dual x-ray absorptiometry. Sarcopenia was classified using the EWGSOP2 and SDOC classifications. Results: Sarcopenia prevalence was 15.1% and 30.9% when classified by the EWGSOP2 and SDOC classifications, respectively. Differences in muscle architecture were observed between sarcopenic and non-sarcopenic groups, with MT showing the largest effect size (Cohen's d EWGSOP2: 0.86; SDOC:0.77). USI was higher in sarcopenic compared to non-sarcopenic individuals classified with EWGSOP2 (5.33 ± 1.30 vs 4.59 ± 0.94, p = .011, Cohen's d:0.69), confirming its sensitivity in detecting sarcopenia. Conclusion: We showed that increased USI values are associated with sarcopenia. This study shows USI as a sensitive, non-invasive marker for sarcopenia classification, supporting its use in clinical screening and monitoring of muscle changes in older adults.
Ključne besede: muscle architecture, aging, muscle quality, muscle function
Objavljeno v DiRROS: 26.03.2026; Ogledov: 200; Prenosov: 103
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4. Association between TMG-derived contractile muscle parameters and MRI-based muscle structure in sarcopeniaKatarina Puš, D. A. Madrid Fuentes, Ashley Weaver, Miloš Kalc, Jeannette R. Mahoney, Boštjan Šimunič, 2026, izvirni znanstveni članek Povzetek: Background: Muscle fat fraction (MFF) obtained through magnetic resonance imaging (MRI) is the gold standard for assessing muscle quality, but it is expensive and time consuming. Portable methods to examine muscles such as tensiomyography (TMG) are emerging and could enable broader screening. This study aims to examine associations between TMG-derived muscle contractile parameters and MFF in older adults with and without sarcopenia. Methods: A sample of 51 Slovenian older adults (53% females) were scanned with Dixon MRIs to evaluate muscle MFF and contractile parameters were assessed with TMG estimating delay time (Td), maximal displacement (Dm) and radial contraction velocity (Vc). Right leg vastus lateralis (VL) and biceps femoris (BF) were analyzed. Sarcopenia was defined using both European Working Group on Sarcopenia in Older People (EWGSOP2) and Sarcopenia Definition and Outcomes Consortium (SDOC) criteria. Regression models adjusted for age and sex were used to assess associations between TMG-derived contractile parameters and MFF. Results: Age- and sex-adjusted models revealed associations between increased MFF and reduced Dm (R2 = .29, p = .003) and Vc (R2 = .32, p = .002) for the VL. SDOC-classified sarcopenic individuals showed increased VL MFF (27.2% vs 22.5%, p = .019),while EWGSOP2 classified sarcopenia displayed no differences. Discussion: The study reveals that increased MFF is associated with reduced muscle contractility in VL. MFF differs between sarcopenic and non-sarcopenic groups using only SDOC criteria. Since the TMG Dm increase is regularly found in atrophic muscles after bed rest, in sarcopenic muscle MFF explains lowering of the Dm, highlighting the TMG potential for early detection of changes in aging muscle.
Ključne besede: sarcopenia, contractile parameters, tensiomyography, muscle fat fraction, muscle function, older adults
Objavljeno v DiRROS: 23.03.2026; Ogledov: 182; Prenosov: 139
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5. Tensiomyography-derived contractile parameters in sarcopenic and non-sarcopenic older adultsKatarina Puš, Miloš Kalc, Boštjan Šimunič, 2026, izvirni znanstveni članek Povzetek: Background: Sarcopenia, the progressive decline in skeletal muscle mass and function, is a major public health concern linked to falls, hospitalization and loss of independence among older adults. Initially defined by reduced muscle mass, later also by reduced muscle strength and function, it is now recognized that standard diagnostic tools do not fully capture complexity of sarcopenia. Tensiomyography (TMG) is a non-invasive method that assesses skeletal muscle contractile parameters, which undergo change with aging and sarcopenia. The aims of this exploratory study are to determine whether TMG could be a method for contractile parameters assessment in sarcopenia classification and to evaluate the relationship between TMG-derived parameters and sarcopenia classification tests. Methods: We included 654 older adults (70.6% women) and included demographics, sarcopenia classification (EWGSOP2, SDOC), muscle strength (handgrip strength, five sit-to-stand), TMG of three leg muscles, muscle mass (bioimpedance), and physical performance (gait speed, timed up-and-go). MANOVA was used to analyze contractile properties and due to low agreement between classifications, we used both classifications. A partial correlation for each sex was conducted to determine the associations between sarcopenia classification tests and TMG-derived parameters of delay time (Td), contraction time (Tc), radial displacement (Dm) and contraction velocity (Vc), controlling for age. Results: One-way MANOVA confirmed difference between sarcopenic and nonsarcopenic participants according to EWGSOP2 and SDOC classifications in TMG-derived contractile parameters in all three muscles, Td was consistently longer and Dm consistently lower in sarcopenic individuals. Post-hoc univariate tests further demonstrated specific differences due to sarcopenia presence. Ageadjusted partial correlations were weak to moderate, ranging between −0.430 and 0.369. Conclusion: Sarcopenic individuals exhibited longer Td and Tc, and smaller Dm, though not consistently across all muscles. Td was longer in all three muscles, reflecting electromechnical delays linked to aging. Dm was consistently lower, suggesting increased muscle stiffness. Correlations between TMG parameters and sarcopenia classification tests indicated that shorter Td and Tc, higher Dm, and greater Vc were associated with higher muscle volume, muscle strength and performance. The findings indicate that TMG parameters may be associated with neuromuscular degeneration and sarcopenia, supporting further exploration of muscle- and sex-specific differences.
Ključne besede: tensiomyography, muscle function, older adults, sarcopenia, seniors
Objavljeno v DiRROS: 04.02.2026; Ogledov: 601; Prenosov: 232
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6. Prevalenca sarkopenije in povezani dejavniki tveganja v Sloveniji : raziskovalni podatki, obravnavani v doktorskem deluKatarina Puš, Miloš Kalc, Saša Pišot, Kaja Teraž, Jure Urbanc, Matej Kleva, Uroš Marušič, Manca Peskar, Luka Šlosar, Boštjan Šimunič, 2026, zaključena znanstvena zbirka raziskovalnih podatkov Povzetek: Podatkovni niz vsebuje anonimizirane presečne podatke, zbrane pri 654 starejših odraslih (≥ 60 let) iz Slovenije. Podatki so bili pridobljeni v okviru presečne raziskave, usmerjene v razvrščanje sarkopenije in analizo mišičnih značilnosti. V podatkovni niz so vključeni demografski podatki (starost, spol), antropometrične meritve ter rezultati meritev mišične jakosti, telesne zmogljivosti in telesne sestave. Mišična jakost je bila ocenjena z merjenjem jakosti stiska pesti in testom petkratnega vstajanja s stola. Telesna zmogljivost je bila ocenjena s hitrostjo hoje in testom vstani in pojdi. Podatki o telesni sestavi in mišični masi so bili pridobljeni z električno bioimpedančno analizo in vključujejo pusto telesno maso, skeletno mišično maso, apendikularno skeletno mišično maso ter indekse, prilagojene telesni višini. Kontraktilne lastnosti skeletnih mišic so bile ocenjene s tenziomiografijo treh mišic spodnjih okončin, pri čemer so bili zabeleženi parametri zakasnitvenega časa, časa kontrakcije, radialnega premika in hitrosti kontrakcije. Dodatni podatki vključujejo prehransko stanje (Mini Nutritional Assessment), gibalno aktivnost in sedentarne navade (Global Physical Activity Questionnaire) ter kognitivne funkcije (Test povezovanja – del A in B). Preiskovanci so bili razvrščeni v skupine glede na več diagnostičnih algoritmov sarkopenije (EWGSOP, EWGSOP2 in njegove različice, SDOC, IWGS in FNIH). Podatki so bili zbrani po standardiziranih protokolih, anonimizirani in opremljeni z metapodatki, kar omogoča njihovo ponovno uporabo v skladu z načeli FAIR.
Ključne besede: sarkopenija, analiza mišičnih značilnost, mišična jakost, telesna sestava, telesna zmogljivost, telesna masa, gibalna aktivnost, sedentarne navade
Objavljeno v DiRROS: 03.02.2026; Ogledov: 375; Prenosov: 307
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8. Influence of selected cognitive performances on musculoskeletal injury occurrence in adult male professional Slovenian PrvaLiga football players in a prospective cohort studyF. Giesche, Manca Peskar, Luka Šlosar, Boštjan Šimunič, Rado Pišot, Uroš Marušič, 2025, izvirni znanstveni članek Povzetek: Evidence suggests athletes with lower baseline cognitive performance are at higher risk of musculoskeletal injuries. This prospective cohort study investigates basic and executive cognitive functions in predicting injuries in 78 professional male football (soccer) players from four Slovenian f irst league teams. Data were collected during the 2018/2019 winter break, and injuries recorded in the second half of that and the 2019/2020 season. Cognitive functions assessed by computerized tests (PsyToolkit) included psychomotor vigilance (simple, choice reaction time) and visuospatial memory (Corsi-block-tapping-test), while pen-and-paper tests assessed motor speed, visual scanning, and executive functions (TMT; Delis-Kaplan-Executive-Function-System). Forty-two players sustained at least one musculoskeletal injury (9 contact injuries), 36 remained injury-free. Logistic regression analyses indicated that none of the cognitive measures significantly influenced injury occurrence (p > 0.05). However, non-significant trends were observed for the TMT ratio score (p = 0.065, OR = 1.64), reflecting cognitive flexibility, and for TMT-A (p = 0.05, OR = 0.60), reflecting visual scanning. Specifically, players with lower cognitive flexibility showed a 64% increase in the odds of sustaining an injury, while better visual scanning performance was associated with a 40% reduction in injury odds. No significant association was found between basic or executive cognitive functions and musculoskeletal injuries in professional male football players. However, a non-significant trend suggested that lower cognitive flexibility may be associated with increased injury risk. These findings underscore the need for larger studies to better clarify the role of executive functions in assessing injury risk in football.
Ključne besede: neurocognitive testing, cognitive-motor tests, sports injury, risk screening
Objavljeno v DiRROS: 08.09.2025; Ogledov: 548; Prenosov: 319
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9. Effects of eccentric- and concentric-based plyometric programmes on strength, speed and tensiomyography parameters of female athletesNikola Prvulović, Ana Lilić, Saša Pantelić, Milan Čoh, Milica Kojadinović, Vesna Vučić, Boštjan Šimunič, 2026, izvirni znanstveni članek Povzetek: The aim of the study was to examine the effects of eccentric- and concentric-based plyometric programmes on the strength, speed, and tensiomyography (TMG) parameters of female athletes. The study included twenty junior female participants from three different sports equally divided into two experimental groups of n = 10. Two plyometric programmes with contrasting designs were conducted for a period of six weeks, with sessions held twice per week. The first plyometric programme (ECC-CON-G) was based on exercises with eccentric, and the second (CONC-CON-G) with concentric contractions. TMG was used to evaluate neuromuscular performances of six muscles of both legs – vastus lateralis (VL), vastus medialis (VM), biceps femoris (BF), semitendinosus (SM), gastrocnemius lateralis (GL), and gastrocnemius medialis (GM)) – and two strength and speed tests: countermovement jump (CMJ), and sprint test at 10 m and 20 m. The results show that both groups had significant effects between pre-post measurements in CMJ (Diff, ECC-CON-G = 9.02%, and CONC-CON-G = 5.59%, p < 0.05), at 10 m (Diff, ECC-CON-G = 9.23%, and CONC-CON-G = 9.35%, p < 0.001), and 20 m (Diff, ECC-CON-G = 6.16%, and CONC-CON-G = 5.35%, p < 0.001), and TMG parameters in ECC-CON-G (all 6 left leg muscles, and right leg-VL, BF, GL, GM, p < 0.05), in CONC-CON-G (left leg-BF, SM, GL, GM, and right leg-VL, BF, GL, GM, p < 0.05). There were significantly better effects in ECC-CON-G compared to CONC-CON-G for CMJ height and time, for only time in 20 m sprint, and TMG parameters for left leg VL and VM, and right leg BF and GM. A plyometric programme based on exercises with eccentric contractions proved more beneficial for strength, speed, and TMG parameters in young female athletes compared to a programme based on concentric contractions.
Ključne besede: tensiomyography, plyometric, countermovement jump, strength, speed, eccentric-concentric contraction
Objavljeno v DiRROS: 04.08.2025; Ogledov: 668; Prenosov: 348
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10. Alterations in Muscle Contractile Properties, Structure, and Function During 10-Day Bed Rest, Post-Recovery, and Following COVID-19 LockdownBoštjan Šimunič, Martino V. Franchi, Fabio Sarto, Elena Monti, zaključena znanstvena zbirka raziskovalnih podatkov Povzetek: We aimed to identify early tensiomyography alterations in six muscles during a 10-day bed rest (BR10), followed by a 30-day recovery period (R+30), and to compare these changes with those observed after the 54-day COVID-19 lockdown in ten healthy males (22.9 ± 5.0 years). Tensiomyography and muscle thickness (sonography) were assessed at baseline, during bed rest, at BR10, R+30, and after the COVID-19 lockdown. Additional assessments included vertical jump performance (force plate), body composition (bioimpedance), physical activity (GPAQ), and lower back pain (VAS). By BR10, participants experienced a 1.9% body mass loss, a 3.8% increase in fat mass, and a 2.4% reduction in muscle mass. While anthropometric parameters returned to baseline by R+30, fat mass increased again by 3.9% post-lockdown. Jump height declined by 10.1% at BR10, returned to baseline at R+30, and remained stable thereafter. Muscle thickness decreased by 7.0% in the vastus lateralis at BR10 and by 10.1% post-lockdown. Tensiomyographic amplitude increased in all five leg muscles prior to BR10, recovered at R+30 and increased again after the COVID-19 lockdown, while a reduction was observed in the erector spinae within the first 48 hours, coinciding with reported lower back pain. In the erector spinae, both delay and contraction time decreased during BR10 and post-lockdown. In contrast, contraction time of the biceps femoris increased before BR10 and remained elevated post-lockdown. Overall, tensiomyographic parameters after the COVID-19 lockdown changed in the same direction as during bed rest, though to a lesser degree, make it a sensitive tool for detecting changes in muscle structural and functional quality after bed rest and reduced activity paradigms.
Ključne besede: Atrophy, Bed rest, Physical inactivity, Skeletal muscle, Tensiomyography
Objavljeno v DiRROS: 25.06.2025; Ogledov: 812; Prenosov: 195
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