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Time course of changes in neuromuscular responses during rides to exhaustion above and below critical power

OBJECTIVES: To examine the time course of changes in electromyographic (EMG) and mechanomyographic (MMG) amplitude (AMP) and mean power frequency (MPF) responses during cycle ergometry to exhaustion performed above (CP(+10%)) and below (CP(-10%)) critical power (CP) to infer motor unit activation st...

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Detalles Bibliográficos
Autores principales: Dinyer, Taylor K., Byrd, M. Travis, Cochrane-Snyman, Kristen C., Jenkins, Nathaniel D.M., Housh, Terry J., Schmidt, Richard J., Johnson, Glen O., Bergstrom, Haley C.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: International Society of Musculoskeletal and Neuronal Interactions 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6737559/
https://www.ncbi.nlm.nih.gov/pubmed/31475933
Descripción
Sumario:OBJECTIVES: To examine the time course of changes in electromyographic (EMG) and mechanomyographic (MMG) amplitude (AMP) and mean power frequency (MPF) responses during cycle ergometry to exhaustion performed above (CP(+10%)) and below (CP(-10%)) critical power (CP) to infer motor unit activation strategies used to maintain power output. METHODS: Participants performed a 3-min all out test to determine CP, and 2 randomly ordered, continuous rides to exhaustion at CP(+10%) and CP(-10%). V̇O(2), EMG AMP, EMG MPF, MMG AMP, MMG MPF, and time to exhaustion (T(lim)) were recorded. Responses at CP(-10%) and CP(+10%) were analyzed separately. RESULTS: At CP(-10%), EMG and MMG AMP were significantly greater than the initial 5% timepoint at 100% T(lim). EMG MPF and MMG MPF reflected a downward trend that resulted in no significant difference between timepoints. At CP(+10%), EMG AMP was significantly greater than the initial 5% timepoint from 60% to 100% T(lim). MMG AMP was less than the initial 5% timepoint at only 50% T(lim). EMG and MMG MPF were significantly less than the initial 5% timepoint at 20% T(lim) and 100% T(lim), respectively. CONCLUSIONS: The time-course of changes in EMG and MMG signals were different at CP(-10%) and CP(+10%), but responses observed indicated cycle ergometry to exhaustion relies on similar motor unit activation strategies.