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Query: "keywords" (vastus lateralis) .

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1.
Diagnostic accuracy of tensiomyography parameters for monitoring peripheral neuromuscular fatigue
Miloš Kalc, Katarina Puš, Armin Paravlić, Jure Urbanc, Boštjan Šimunič, 2023, original scientific article

Abstract: The diagnostic accuracy of tensiomyography (TMG) parameters compared to the gold standard in neuromuscular fatigue evaluation using voluntary and electrically induced muscle activation is unclear. This study aimed to investigate the diagnostic accuracy of TMG parameters to detect individual changes after interventions that were designed to induce central or peripheral fatigue. Nineteen males (age: 32.2 ± 9.3 years) performed two interventions, consisting of maintaining 25% of maximal voluntary contraction (MViC25%) and a 30 s all-out cycling test (Wingate), respectively. TMG parameters, maximum voluntary contraction (PtMViC), voluntary activation (VA%) and electrically elicited double twitches (Dtw) were assessed on the knee extensors before (PRE), one minute (POST) and seven minutes after (POST7) the intervention. The diagnostic accuracy (AUC) of TMG parameters were evaluated in comparison to two criteria measures (PtMViC and Dtw). RM ANOVA revealed a significant interaction between the effects of intervention and time on VA% (p = 0.001) and Dtw (p < 0.001) but not for PtMViC (p = 0.420). AUC showed that TMG parameters had a good ability in detecting muscular fatigue assessed by Dtw but not by PtMViC. The results of the current study suggest that TMG parameters can be used to monitor peripheral neuromuscular fatigue.
Keywords: tensiomyography, vastus lateralis, MVC, twitch
Published in DiRROS: 13.06.2023; Views: 313; Downloads: 171
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2.
Absence of an aging-related increase in fibre type grouping in athletes and non-athletes
Guy A. M. Messa, Mathew Piasecki, Joern Rittweger, Jamie McPhee, Erika Koltai, Zsolt Radak, Boštjan Šimunič, Ari Heinonen, Harri Suominen, Marko T. Korhonen, Hans Degens, 2020, original scientific article

Abstract: The ageing-related loss of muscle mass is thought to be partly attributable to motor neuron loss and motor unit remodelling that result in fibre type grouping. We examined fibre type grouping in 19- to 85-year-old athletes and non-athletes and evaluated to which extent any observed grouping is explained by the fibre type composition of the muscle. Since regular physical activity may stimulate reinnervation, we hypothesised that fibre groups are larger in master athletes than in age-matched non-athletes. Fibre type grouping was assessed in m. vastus lateralis biopsies from 22 young (19-27 years) and 35 healthy older (66-82 years) non-athletes, and 14 young (20-29 years), 51 middle-aged (38%65 years) and 31 older (66-85 years) athletes. An "enclosed fibre" was any muscle fibre of a particular type surrounded by fibres of the same type only. A fibre type group was defined as a group of fibres with at least one enclosed fibre. Only type II fibre cross-sectional area (FCSA) showed an age-related decline that was greater in athletes (p < 0.001) than in non-athletes (p = 0.012). There was no significant age-related effect on fibre group size or fibre group number in athletes or non-athletes, and the observed grouping was similar to that expected from the fibre type composition. At face value these observations do 1) neither show evidence for an age-related loss and remodelling of motor units nor 2) improved reinnervation with regular physical activity, but 3) histological examination may not reveal the full extent of ageing-related motor unit remodelling.
Keywords: aging, denervation, fibre type, reinnervation, vastus lateralis
Published in DiRROS: 24.03.2021; Views: 1021; Downloads: 785
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