Journal article
Effects of fatiguing, submaximal high‐ versus low‐torque isometric exercise on motor unit recruitment and firing behavior
Physiological reports, Vol.6(8), pp.e13675-n/a
04/19/2018
DOI: 10.14814/phy2.13675
PMCID: PMC5907942
PMID: 29673119
Abstract
The purpose of this investigation was to evaluate the effects of repeated, high‐ (HT: 70% MVIC) versus low‐torque (LT: 30% MVIC) isometric exercise performed to failure on motor unit (MU) recruitment and firing behavior of the vastus lateralis. Eighteen resistance‐trained males (23.1 ± 3.8 years) completed familiarization, followed by separate experimental sessions in which they completed either HT or LT exercise to failure in random order. LT exercise resulted in a greater time to task failure and a more dramatic decline in the muscle's force capacity, but the total work completed was similar for HT and LT exercise. An examination of the firing trains from 4670 MUs recorded during exercise revealed that firing rates generally increased during HT and LT exercise, but were higher during HT than LT exercise. Furthermore, recruitment thresholds (RT) did not significantly change during HT exercise, whereas the RT of the smallest MUs increased and the RT for the moderate to large MUs decreased during LT exercise. Both HT and LT exercise resulted in the recruitment of additional higher threshold MUs in order to maintain torque production. However, throughout exercise, HT required the recruitment of larger MUs than did LT exercise. In a few cases, however, MUs were recruited by individuals during LT exercise that were similar in size and original (pre) RT to those detected during HT exercise. Thus, the ability to achieve full MU recruitment during LT exercise may be dependent on the subject. Consequently, our data emphasize the task and subject dependency of muscle fatigue.
Details
- Title: Subtitle
- Effects of fatiguing, submaximal high‐ versus low‐torque isometric exercise on motor unit recruitment and firing behavior
- Creators
- Tyler W. D Muddle - Oklahoma State UniversityRyan J Colquhoun - Oklahoma State UniversityMitchel A Magrini - Oklahoma State UniversityMicheal J Luera - Oklahoma State UniversityJason M DeFreitas - Oklahoma State UniversityNathaniel D. M Jenkins - Oklahoma State University
- Resource Type
- Journal article
- Publication Details
- Physiological reports, Vol.6(8), pp.e13675-n/a
- DOI
- 10.14814/phy2.13675
- PMID
- 29673119
- PMCID
- PMC5907942
- NLM abbreviation
- Physiol Rep
- eISSN
- 2051-817X
- Publisher
- John Wiley and Sons Inc
- Alternative title
- T. W. D. Muddle et al
- Language
- English
- Date published
- 04/19/2018
- Academic Unit
- Center for Social Science Innovation; Injury Prevention Research Center; Health, Sport, and Human Physiology
- Record Identifier
- 9984259656402771
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