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Muscle function and fatigability of trunk flexors in males and females

BACKGROUND: Optimal function of the abdominal muscles is necessary for several life functions including lifting and carrying tasks. Sex differences in strength and fatigability are established for many limb muscles and back extensor muscles, but it is unknown if sex differences exist for the abdomin...

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Autores principales: Deering, Rita E., Senefeld, Jonathon W., Pashibin, Tatyana, Neumann, Donald A., Hunter, Sandra K.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5393031/
https://www.ncbi.nlm.nih.gov/pubmed/28428836
http://dx.doi.org/10.1186/s13293-017-0133-y
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author Deering, Rita E.
Senefeld, Jonathon W.
Pashibin, Tatyana
Neumann, Donald A.
Hunter, Sandra K.
author_facet Deering, Rita E.
Senefeld, Jonathon W.
Pashibin, Tatyana
Neumann, Donald A.
Hunter, Sandra K.
author_sort Deering, Rita E.
collection PubMed
description BACKGROUND: Optimal function of the abdominal muscles is necessary for several life functions including lifting and carrying tasks. Sex differences in strength and fatigability are established for many limb muscles and back extensor muscles, but it is unknown if sex differences exist for the abdominal muscles despite their functional importance. METHODS: Eighteen females (24.3 ± 4.8 years) and 15 males (24.1 ± 6.6 years) performed (1) isometric trunk flexion maximal voluntary contractions (MVCs) in a range of trunk positions to establish a torque-angle curve and (2) submaximal (50% MVC), intermittent isometric contraction (6 s on, 4 s off) until task failure to determine fatigability of the trunk flexor muscles. Dual X-ray absorptiometry quantified body fat and lean mass. Physical activity levels were quantified with a questionnaire. Torque-angle curves, electromyography (EMG), MVC torque, and torque steadiness were compared with repeated measures ANOVA with sex as a between-subjects factor. RESULTS: For the torque-angle curve, MVC torque was reduced as the trunk angle increased toward flexion (p < 0.001). Males had greater MVC torque than females at the extended positions (31% difference), with no sex differences in torque in upright sitting (p > 0.05). Time-to-task failure for the submaximal fatigability task in upright sitting was similar between males and females (12.4 ± 7 vs 10.5 ± 6 min). Time-to-task failure was positively associated with strength (r = 0.473, p = 0.005) and self-reported physical activity (r = 0.456, p = 0.030). Lean mass in the trunk was positively associated with trunk flexor strength (r = 0.378, p = 0.011) and self-reported physical activity (r = 0.486, p = 0.007). Finally, torque steadiness [coefficient of variation of torque (CV)] during submaximal isometric contractions decreased with contraction intensity and was similar for males and females across all intensities. CONCLUSIONS: Unlike many limb muscle groups, males and females had similar fatigability and torque steadiness of the trunk flexor muscles during isometric contractions. Stronger individuals, however, exhibited less fatigability. Lower self-reported physical activity was associated with greater fatigability of trunk flexor muscles. The relationship between strength and fatigability of the trunk flexor muscles and physical activity supports the importance of abdominal muscle strengthening to offset fatigability in both males and females.
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spelling pubmed-53930312017-04-20 Muscle function and fatigability of trunk flexors in males and females Deering, Rita E. Senefeld, Jonathon W. Pashibin, Tatyana Neumann, Donald A. Hunter, Sandra K. Biol Sex Differ Research BACKGROUND: Optimal function of the abdominal muscles is necessary for several life functions including lifting and carrying tasks. Sex differences in strength and fatigability are established for many limb muscles and back extensor muscles, but it is unknown if sex differences exist for the abdominal muscles despite their functional importance. METHODS: Eighteen females (24.3 ± 4.8 years) and 15 males (24.1 ± 6.6 years) performed (1) isometric trunk flexion maximal voluntary contractions (MVCs) in a range of trunk positions to establish a torque-angle curve and (2) submaximal (50% MVC), intermittent isometric contraction (6 s on, 4 s off) until task failure to determine fatigability of the trunk flexor muscles. Dual X-ray absorptiometry quantified body fat and lean mass. Physical activity levels were quantified with a questionnaire. Torque-angle curves, electromyography (EMG), MVC torque, and torque steadiness were compared with repeated measures ANOVA with sex as a between-subjects factor. RESULTS: For the torque-angle curve, MVC torque was reduced as the trunk angle increased toward flexion (p < 0.001). Males had greater MVC torque than females at the extended positions (31% difference), with no sex differences in torque in upright sitting (p > 0.05). Time-to-task failure for the submaximal fatigability task in upright sitting was similar between males and females (12.4 ± 7 vs 10.5 ± 6 min). Time-to-task failure was positively associated with strength (r = 0.473, p = 0.005) and self-reported physical activity (r = 0.456, p = 0.030). Lean mass in the trunk was positively associated with trunk flexor strength (r = 0.378, p = 0.011) and self-reported physical activity (r = 0.486, p = 0.007). Finally, torque steadiness [coefficient of variation of torque (CV)] during submaximal isometric contractions decreased with contraction intensity and was similar for males and females across all intensities. CONCLUSIONS: Unlike many limb muscle groups, males and females had similar fatigability and torque steadiness of the trunk flexor muscles during isometric contractions. Stronger individuals, however, exhibited less fatigability. Lower self-reported physical activity was associated with greater fatigability of trunk flexor muscles. The relationship between strength and fatigability of the trunk flexor muscles and physical activity supports the importance of abdominal muscle strengthening to offset fatigability in both males and females. BioMed Central 2017-04-17 /pmc/articles/PMC5393031/ /pubmed/28428836 http://dx.doi.org/10.1186/s13293-017-0133-y Text en © The Author(s). 2017 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research
Deering, Rita E.
Senefeld, Jonathon W.
Pashibin, Tatyana
Neumann, Donald A.
Hunter, Sandra K.
Muscle function and fatigability of trunk flexors in males and females
title Muscle function and fatigability of trunk flexors in males and females
title_full Muscle function and fatigability of trunk flexors in males and females
title_fullStr Muscle function and fatigability of trunk flexors in males and females
title_full_unstemmed Muscle function and fatigability of trunk flexors in males and females
title_short Muscle function and fatigability of trunk flexors in males and females
title_sort muscle function and fatigability of trunk flexors in males and females
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5393031/
https://www.ncbi.nlm.nih.gov/pubmed/28428836
http://dx.doi.org/10.1186/s13293-017-0133-y
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