Muscle fatigue, bioenergetic responses and metabolic economy during load‐ and velocity‐based maximal dynamic contractions in young and older adults
Abstract We evaluated whether task‐dependent, age‐related differences in muscle fatigue (contraction‐induced decline in normalized power) develop from differences in bioenergetics or metabolic economy (ME; mass‐normalized work/mM ATP). We used magnetic resonance spectroscopy to quantify intracellula...
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| Format: | Article |
| Language: | English |
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Wiley
2023-11-01
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| Series: | Physiological Reports |
| Subjects: | |
| Online Access: | https://doi.org/10.14814/phy2.15876 |
| _version_ | 1797449847950802944 |
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| author | Liam F. Fitzgerald Miles F. Bartlett Jane A. Kent |
| author_facet | Liam F. Fitzgerald Miles F. Bartlett Jane A. Kent |
| author_sort | Liam F. Fitzgerald |
| collection | DOAJ |
| description | Abstract We evaluated whether task‐dependent, age‐related differences in muscle fatigue (contraction‐induced decline in normalized power) develop from differences in bioenergetics or metabolic economy (ME; mass‐normalized work/mM ATP). We used magnetic resonance spectroscopy to quantify intracellular metabolites in vastus lateralis muscle of 10 young and 10 older adults during two maximal‐effort, 4‐min isotonic (20% maximal torque) and isokinetic (120°s−1) contraction protocols. Fatigue, inorganic phosphate (Pi), and pH (p ≥ 0.213) differed by age during isotonic contractions. However, older had less fatigue (p ≤ 0.011) and metabolic perturbation (lower [Pi], greater pH; p ≤ 0.031) than young during isokinetic contractions. ME was lower in older than young during isotonic contractions (p ≤ 0.003), but not associated with fatigue in either protocol or group. Rather, fatigue during both tasks was linearly related to changes in [H+], in both groups. The slope of fatigue versus [H+] was 50% lower in older than young during isokinetic contractions (p ≤ 0.023), consistent with less fatigue in older during this protocol. Overall, regardless of age or task type, acidosis, but not ME, was the primary mechanism for fatigue in vivo. The source of the age‐related differences in contraction‐induced acidosis in vivo remains to be determined, as does the apparent task‐dependent difference in the sensitivity of muscle to [H+]. |
| first_indexed | 2024-03-09T14:31:54Z |
| format | Article |
| id | doaj.art-93edd26a4dbb475785e622968d4657aa |
| institution | Directory Open Access Journal |
| issn | 2051-817X |
| language | English |
| last_indexed | 2024-03-09T14:31:54Z |
| publishDate | 2023-11-01 |
| publisher | Wiley |
| record_format | Article |
| series | Physiological Reports |
| spelling | doaj.art-93edd26a4dbb475785e622968d4657aa2023-11-28T00:21:19ZengWileyPhysiological Reports2051-817X2023-11-011122n/an/a10.14814/phy2.15876Muscle fatigue, bioenergetic responses and metabolic economy during load‐ and velocity‐based maximal dynamic contractions in young and older adultsLiam F. Fitzgerald0Miles F. Bartlett1Jane A. Kent2Muscle Physiology Laboratory, Department of Kinesiology University of Massachusetts Amherst Massachusetts USAMuscle Physiology Laboratory, Department of Kinesiology University of Massachusetts Amherst Massachusetts USAMuscle Physiology Laboratory, Department of Kinesiology University of Massachusetts Amherst Massachusetts USAAbstract We evaluated whether task‐dependent, age‐related differences in muscle fatigue (contraction‐induced decline in normalized power) develop from differences in bioenergetics or metabolic economy (ME; mass‐normalized work/mM ATP). We used magnetic resonance spectroscopy to quantify intracellular metabolites in vastus lateralis muscle of 10 young and 10 older adults during two maximal‐effort, 4‐min isotonic (20% maximal torque) and isokinetic (120°s−1) contraction protocols. Fatigue, inorganic phosphate (Pi), and pH (p ≥ 0.213) differed by age during isotonic contractions. However, older had less fatigue (p ≤ 0.011) and metabolic perturbation (lower [Pi], greater pH; p ≤ 0.031) than young during isokinetic contractions. ME was lower in older than young during isotonic contractions (p ≤ 0.003), but not associated with fatigue in either protocol or group. Rather, fatigue during both tasks was linearly related to changes in [H+], in both groups. The slope of fatigue versus [H+] was 50% lower in older than young during isokinetic contractions (p ≤ 0.023), consistent with less fatigue in older during this protocol. Overall, regardless of age or task type, acidosis, but not ME, was the primary mechanism for fatigue in vivo. The source of the age‐related differences in contraction‐induced acidosis in vivo remains to be determined, as does the apparent task‐dependent difference in the sensitivity of muscle to [H+].https://doi.org/10.14814/phy2.15876acidosisagingglycolysisinorganic phosphateoxidative phosphorylationsarcopenia |
| spellingShingle | Liam F. Fitzgerald Miles F. Bartlett Jane A. Kent Muscle fatigue, bioenergetic responses and metabolic economy during load‐ and velocity‐based maximal dynamic contractions in young and older adults Physiological Reports acidosis aging glycolysis inorganic phosphate oxidative phosphorylation sarcopenia |
| title | Muscle fatigue, bioenergetic responses and metabolic economy during load‐ and velocity‐based maximal dynamic contractions in young and older adults |
| title_full | Muscle fatigue, bioenergetic responses and metabolic economy during load‐ and velocity‐based maximal dynamic contractions in young and older adults |
| title_fullStr | Muscle fatigue, bioenergetic responses and metabolic economy during load‐ and velocity‐based maximal dynamic contractions in young and older adults |
| title_full_unstemmed | Muscle fatigue, bioenergetic responses and metabolic economy during load‐ and velocity‐based maximal dynamic contractions in young and older adults |
| title_short | Muscle fatigue, bioenergetic responses and metabolic economy during load‐ and velocity‐based maximal dynamic contractions in young and older adults |
| title_sort | muscle fatigue bioenergetic responses and metabolic economy during load and velocity based maximal dynamic contractions in young and older adults |
| topic | acidosis aging glycolysis inorganic phosphate oxidative phosphorylation sarcopenia |
| url | https://doi.org/10.14814/phy2.15876 |
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