Estimation of critical end-test torque using neuromuscular electrical stimulation of the quadriceps in humans
Deutscher übersetzter Titel: | Abschätzung des kritischen Endtest-Drehmoments mittels neuromuskulärer elektrischer Stimulation des Quadrizeps beim Menschen |
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Autor: | Janzen, Natalie R.; Hight, Robert E.; Patel, Darshit S.; Campbell, Jason A.; Larson, Rebecca D.; Black, Christopher D. |
Erschienen in: | European journal of applied physiology |
Veröffentlicht: | 118 (2018), 7, S. 1407-1414, Lit. |
Format: | Literatur (SPOLIT) |
Publikationstyp: | Zeitschriftenartikel |
Medienart: | Elektronische Ressource (online) Gedruckte Ressource |
Sprache: | Englisch |
ISSN: | 1439-6319, 0301-5548 |
DOI: | 10.1007/s00421-018-3872-5 |
Schlagworte: | |
Online Zugang: | |
Erfassungsnummer: | PU201903002140 |
Quelle: | BISp |
Abstract des Autors
Characterization of critical power/torque (CP/CT) during voluntary exercise requires maximal effort, making difficult for those with neuromuscular impairments. To address this issue we sought to determine if electrically stimulated intermittent isometric exercise resulted in a critical end-test torque (ETT) that behaved similar to voluntary CT. In the first experiment participants (n = 9) completed four bouts of stimulated exercise at a 3:2 duty cycle, at frequencies of 100, 50, 25 Hz, and a low frequency below ETT (Sub-ETT; </= 15 Hz). The second experiment (n = 20) consisted of four bouts at a 2:2 duty cycle—two bouts at 100 Hz, one at an intermediate frequency (15–30 Hz), and one at Sub-ETT. The third experiment (n = 12) consisted of two bouts at 50 Hz at a 3:2 duty* cycle with proximal blood flow occlusion during one of the bouts. ETT torque was similar (p >/= 0.43) within and among stimulation frequencies in experiment 1. No fatigue was observed during the Sub-ETT bouts (p > 0.05). For experiment 2, ETT was similar at 100 Hz and at the intermediate frequency (p >/= 0.29). Again, Sub-ETT stimulation did not result in fatigue (p > 0.05). Altering oxygen delivery by altering the duty cycle (3:2 vs. 2:2; p = 0.02) and by occlusion (p < 0.001) resulted in lower ETT values. Stimulated exercise resulted in an ETT that was consistent from day-to-day and similar regardless of initial torque, as long as that torque exceeded ETT, and was sensitive to oxygen delivery. As such we propose it represents a parameter similar to voluntary CT.