1. Inter-person differences in isometric coactivations of triceps surae and tibialis anterior decrease in young, but not in older adults after 14 days of bed restMatjaž Divjak, Gašper Sedej, Nina Murks, Mitja Gerževič, Uroš Marušič, Rado Pišot, Boštjan Šimunič, Aleš Holobar, 2022, izvirni znanstveni članek Opis: We examined activation patterns of the gastrocnemius medialis (GM), gastrocnemius lateralis (GL), soleus (SO), and tibialis anterior (TA) muscles in eight older (58.4 ± 3.3 years) and seven young (23.1 ± 2.9 years) participants, before and after 14 days of horizontal bed rest. Visual feedback on the exerted muscle torque was provided to the participants. The discharge patterns of individual motor units (MUs) were studied in three repetitions of isometric plantar flexion at 30 and 60% of Maximum Voluntary Contraction (MVC), before, and 1 day after the 14-day bed rest, respectively. In the GL and GM muscles, the older participants demonstrated higher MU discharge rates than the young, regardless of the contraction level, both before and after the bed rest. In the TA and SO muscles, the differences between the older and young participants were less consistent. Detailed analysis revealed person-specific changes in the MU discharge rates after the bed rest. To quantify the coactivation patterns we calculated the correlation coefficients between the cumulative spike trains of identified MUs from each muscle, and measured the root mean square difference of the correlation coefficients between the trials of the same session (intra-session variability) and between different sessions (inter-session variability) in each participant (intra-person comparison) and across participants (inter-person comparison). In the intra-person comparison, the inter-session variability was higher than the intra-session variability, either before or after the bed rest. At 60% MVC torque, the young demonstrated higher inter-person variability of coactivation than the older participants, but this variability decreased significantly after the bed rest. In older participants, inter-person variability was consistently lower at 60% than at 30% MVC torque. In young participants, inter-person variability became lower at 60% than at 30% MVC torque only after the bed rest. Precaution is required when analyzing the MU discharge and coactivation patterns, as individual persons demonstrate individual adaptations to aging or bed rest.
Ključne besede: mišičnoskeletni sistem, mišice, bed rest, staranje, elektromiografija, high density electromyography, muscle disuse, motor units, discharge rate, aging
Objavljeno v DKUM: 07.07.2023; Ogledov: 539; Prenosov: 61
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2. Vpliv osnovnih gibalnih in funkcionalnih sposobnosti na hitrost vodenja žoge pri 10-17 let starih nogometašihMatija Maršič, Branko Zupan, Rado Pišot, Mitja Gerževič, 2016, izvirni znanstveni članek Opis: Cilj študije je bil ugotoviti povezanost izbranih gibalnih in funkcionalnih sposobnosti s hitrostjo vodenja žoge s spremembo smeri pri 183 mladih nogometaših med 10. in 17. letom starosti (starost 13,0 ± 1,8 leta; telesna višina 161,8 ± 13,3 cm; telesna masa 53,3 ± 14,7 kg). Na osnovi pridobljenih podatkov in rezultatov smo ugotovili, da bi se bilo treba po 13. letu poleg drugim, za nogometno igro pomembnim sposobnostim, bolj posvetiti razvoju elastične odrivne moči, po 16. letu pa vse bolj oz. še bolj poudarjati visoko hitrost in kakovost izvedbe specifičnih nogometnih vsebin tipa hitrosti in agilnosti. Za uspešno vodenje s spremembo smeri je pri 10–11 letih pomembna predvsem agilnost, pri 12–13 letih tudi relativna odrivna elastična moč in aerobno-anaerobna vzdržljivost, pri 14–15 letih predvsem aerobno-anaerobna vzdržljivost, pri 16–17 letih pa poleg agilnosti še hitrost pospeševanja in največja hitrost teka.
Ključne besede: nogomet, gibalne sposobnosti, motorične sposobnosti, gibalni razvoj, otroci
Objavljeno v DKUM: 12.10.2017; Ogledov: 1295; Prenosov: 143
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