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Different discrete motor-unit activation patterns in the flexor carpi radialis in boys and men.
Woods, Stacey; McKiel, Andrew; Herda, Trent; Klentrou, Panagiota; Holmes, Michael W R; Gabriel, David A; Falk, Bareket.
Afiliación
  • Woods S; Department of Kinesiology, Faculty of Applied Health Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada.
  • McKiel A; Centre for Bone and Muscle Health, Brock University, St. Catharines, ON, Canada.
  • Herda T; Department of Kinesiology, Faculty of Applied Health Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada.
  • Klentrou P; Centre for Bone and Muscle Health, Brock University, St. Catharines, ON, Canada.
  • Holmes MWR; School of Education and Human Sciences, University of Kansas, Lawrence, KS, USA.
  • Gabriel DA; Department of Kinesiology, Faculty of Applied Health Sciences, Brock University, St. Catharines, ON, L2S 3A1, Canada.
  • Falk B; Centre for Bone and Muscle Health, Brock University, St. Catharines, ON, Canada.
Eur J Appl Physiol ; 124(6): 1933-1942, 2024 Jun.
Article en En | MEDLINE | ID: mdl-38285213
ABSTRACT

BACKGROUND:

Lower activation of higher threshold (type-II) motor units (MUs) has been suggested in children compared with adults. We examined child-adult differences in discrete MU activation of the flexor carpi radialis (FCR).

METHODS:

Fifteen boys (10.2 ± 1.4 years), and 17 men (25.0 ± 2.7 years) completed 2 laboratory sessions. Following a habituation session, maximal voluntary isometric wrist flexion torque (MVIC) was determined before completing trapezoidal isometric contractions at 70%MVIC. Surface electromyography was captured by Delsys Trigno Galileo sensors and decomposed into individual MU action potential trains. Recruitment threshold (RT), and MU firing rates (MUFR) were calculated.

RESULTS:

MVIC was significantly greater in men (10.19 ± 1.92 Nm) than in boys (4.33 ± 1.47 Nm) (p < 0.05), but not statistically different after accounting for differences in body size. Mean MUFR was not different between boys (17.41 ± 7.83 pps) and men (17.47 ± 7.64 pps). However, the MUFR-RT slope was significantly (p < 0.05) steeper (more negative) in boys, reflecting a progressively greater decrease in MUFR with increasing RT. Additionally, boys recruited more of their MUs early in the ramped contraction.

CONCLUSION:

Compared with men, boys tended to recruit their MUs earlier and at a lower percentage of MVIC. This difference in MU recruitment may explain the greater decrease in MUFR with increasing RT in boys compared with men. Overall, these findings suggest an age-related difference in the neural strategy used to develop moderate-high torque in wrist flexors, where boys recruit more of their MUs earlier in the force gradation process, possibly resulting in a narrower recruitment range.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Reclutamiento Neurofisiológico / Músculo Esquelético / Contracción Isométrica Límite: Adult / Child / Humans / Male Idioma: En Revista: Eur J Appl Physiol Asunto de la revista: FISIOLOGIA Año: 2024 Tipo del documento: Article País de afiliación: Canadá Pais de publicación: Alemania
Texto completo
Añadir a Mi BVS
Imprimir
XML
PubMed Links
Buscar en Google

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Reclutamiento Neurofisiológico / Músculo Esquelético / Contracción Isométrica Límite: Adult / Child / Humans / Male Idioma: En Revista: Eur J Appl Physiol Asunto de la revista: FISIOLOGIA Año: 2024 Tipo del documento: Article País de afiliación: Canadá Pais de publicación: Alemania