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O'Bryan SJ, Hiam D, Lamon S. Single-session measures of quadriceps neuromuscular function are reliable in healthy females and unaffected by age. Eur J Appl Physiol 2024; 124:1719-1732. [PMID: 38189826 PMCID: PMC11130065 DOI: 10.1007/s00421-023-05395-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Accepted: 12/07/2023] [Indexed: 01/09/2024]
Abstract
PURPOSE This study aimed to determine the inter-session reliability of quadriceps neuromuscular function measurements in healthy young and older females. METHODS Twenty-six females aged 19-74 years completed two identical experimental sessions on different days. Quadriceps neuromuscular function measurements included isometric maximal voluntary force, high- and low-frequency twitch force, voluntary and evoked (H-reflex, M-wave) electromyography (EMG), and estimated maximal torque, velocity and power derived from torque-velocity relationships. Intra-class correlation coefficients (ICCs), coefficients of variation (CoV) and Bland-Altman plots assessed inter-session reliability. The effect of age on reliability was assessed by linear regression. RESULTS Excellent reliability (ICC > 0.8) was shown for all voluntary and evoked mechanical outcomes. Vastus lateralis EMG outcomes showed excellent reliability (ICC > 0.8) with CoVs < 12%, which were better than those of vastus medialis and rectus femoris. Age was not associated with reliability for 27/28 outcomes (P > 0.05). CONCLUSION Excellent reliability of voluntary and evoked force and vastus lateralis EMG outcomes measured in healthy females can be attained in one experimental session, irrespective of age. Female neuromuscular function can be accurately assessed across the lifespan with minimal inconvenience, increasing feasibility for future research. The random error should however be considered when quantifying age-related differences in neuromuscular function.
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Affiliation(s)
- Steven J O'Bryan
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, 221 Burwood Highway, Burwood, Geelong, VIC, 3125, Australia.
- Institute for Health and Sport, Victoria University, Melbourne, Australia.
| | - Danielle Hiam
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, 221 Burwood Highway, Burwood, Geelong, VIC, 3125, Australia
| | - Séverine Lamon
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, 221 Burwood Highway, Burwood, Geelong, VIC, 3125, Australia
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Zarzissi S, Zghal F, Bouchiba M, Rebai H, Fekih N, Bouzid MA. Delayed neuromuscular fatigue recovery unveils reduced fatigue tolerance in elderly following maximal intermittent exercise. Eur J Appl Physiol 2024:10.1007/s00421-024-05499-y. [PMID: 38758411 DOI: 10.1007/s00421-024-05499-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 04/30/2024] [Indexed: 05/18/2024]
Abstract
The aim of the study was to assess the impact of aging on neuromuscular fatigue and recovery. Ten young (23.08 ± 1.43 years) and older (61.19 ± 1.80 years) males performed an intermittent maximal isometric exercise with the knee extensors followed by 27 min of recovery. Maximal voluntary contraction (MVC), total work (W'), voluntary activation (VA), potentiated resting twitch (Ptw), and electromyography (EMG) were recorded and then analyzed. Peripheral and central fatigue following exercise were lower in old compared to young (- 29.99% vs. - 42.68% and - 14.55 vs. - 20.02%; P < 0.05, respectively). Despite old performing 50% less work, RMS/Mmax reduction was similar between old and young (- 26.46% vs. - 29.93%; P > 0.05, respectively). During the recovery period, our results showed that recovery of the MVC was impaired for old (14.93% for old vs. 30.66% for young) and still incomplete until 27 min.VA increased significantly compared to post exercise after 1 min only for young (P = 0.001), potentially affecting the recovery pattern of MVC during the early phase due to their significant correlation (r2 = 0.58, P = 0.01). Peripheral fatigue recovery was also lower for old (11.18% vs. 18.72%; P < 0.001), and both groups failed to recover their baseline value (both P < 0.005). The lower peripheral and central fatigue observed in elderly following exercise appears for the first instance as a fatigue resistance. However, the delayed neuromuscular recovery reveals instead a reduced fatigue tolerance reflecting age-related alteration within contractile properties and/or within central nervous system.
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Affiliation(s)
- Slim Zarzissi
- High Institute of Sport and Physical Education, Education, Motor Skills, Sport and Health (EM2S) Laboratory, University of Sfax, LR19JS01, Sfax, Tunisia.
| | - Firas Zghal
- High Institute of Sport and Physical Education, Education, Motor Skills, Sport and Health (EM2S) Laboratory, University of Sfax, LR19JS01, Sfax, Tunisia
| | - Mustapha Bouchiba
- High Institute of Sport and Physical Education, Education, Motor Skills, Sport and Health (EM2S) Laboratory, University of Sfax, LR19JS01, Sfax, Tunisia
| | - Haithem Rebai
- Tunisian Research Laboratory 'Sports Performance Optimization', National Center of Medicine and Science in Sports (CNMSS), (CNMSS-LR09SEP01), Tunis, Tunisia
| | - Nadia Fekih
- High Institute of Sport and Physical Education, Education, Motor Skills, Sport and Health (EM2S) Laboratory, University of Sfax, LR19JS01, Sfax, Tunisia
| | - Mohamed Amine Bouzid
- High Institute of Sport and Physical Education, Education, Motor Skills, Sport and Health (EM2S) Laboratory, University of Sfax, LR19JS01, Sfax, Tunisia
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Bowen M, Samozino P, Vonderscher M, Dutykh D, Morel B. Mathematical modeling of exercise fatigability in the severe domain: A unifying integrative framework in isokinetic condition. J Theor Biol 2024; 578:111696. [PMID: 38070705 DOI: 10.1016/j.jtbi.2023.111696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 11/15/2023] [Accepted: 12/04/2023] [Indexed: 12/22/2023]
Abstract
Muscle fatigue is the decay in the ability of muscles to generate force, and results from neural and metabolic perturbations. This article presents an integrative mathematical model that describes the decrease in maximal force capacity (i.e. fatigue) over exercises performed at intensities above the critical force Fc (i.e. severe domain). The model unifies the previous Critical Power Model and All-Out Model and can be applied to any exercise described by a changing force F over time. The assumptions of the model are (i) isokinetic conditions, an intensity domain of Fc
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Affiliation(s)
- M Bowen
- Laboratoire Interuniversitaire de Biologie de la Motricité LIBM, EA 7424, Savoie Mont Blanc University, F-7300, Chambéry, France.
| | - P Samozino
- Laboratoire Interuniversitaire de Biologie de la Motricité LIBM, EA 7424, Savoie Mont Blanc University, F-7300, Chambéry, France
| | - M Vonderscher
- Laboratoire Interuniversitaire de Biologie de la Motricité LIBM, EA 7424, Savoie Mont Blanc University, F-7300, Chambéry, France
| | - D Dutykh
- Mathematics Department, Khalifa University of Science and Technology, PO Box 127788, Abu Dhabi, United Arab Emirates; Causal Dynamics Pty Ltd, WA 6009, Perth, Australia
| | - B Morel
- Laboratoire Interuniversitaire de Biologie de la Motricité LIBM, EA 7424, Savoie Mont Blanc University, F-7300, Chambéry, France
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Fitzgerald LF, Bartlett MF, Kent JA. Muscle fatigue, bioenergetic responses and metabolic economy during load- and velocity-based maximal dynamic contractions in young and older adults. Physiol Rep 2023; 11:e15876. [PMID: 37996974 PMCID: PMC10667588 DOI: 10.14814/phy2.15876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 11/07/2023] [Accepted: 11/07/2023] [Indexed: 11/25/2023] Open
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+ ].
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Affiliation(s)
- Liam F. Fitzgerald
- Muscle Physiology Laboratory, Department of KinesiologyUniversity of MassachusettsAmherstMassachusettsUSA
| | - Miles F. Bartlett
- Muscle Physiology Laboratory, Department of KinesiologyUniversity of MassachusettsAmherstMassachusettsUSA
| | - Jane A. Kent
- Muscle Physiology Laboratory, Department of KinesiologyUniversity of MassachusettsAmherstMassachusettsUSA
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Wrucke DJ, Kuplic A, Adam M, Hunter SK, Sundberg CW. Neural and muscular contributions to the age-related loss in power of the knee extensors in men and women. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.24.563851. [PMID: 37961177 PMCID: PMC10634815 DOI: 10.1101/2023.10.24.563851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The mechanisms for the loss in limb muscle power in old (60-79 years) and very old (≥80 years) adults and whether the mechanisms differ between men and women are not well-understood. We compared maximal power of the knee extensor muscles between young, old, and very old men and women and identified the neural and muscular factors contributing to the age-related loss of power. 31 young (22.9±3.0 years, 15 women), 83 old (70.4±4.9 years, 39 women), and 16 very old adults (85.8±4.2 years, 9 women) performed maximal isokinetic contractions at 14 different velocities (30-450°/s) to identify peak power. Voluntary activation (VA) and contractile properties were assessed with transcranial magnetic stimulation to the motor cortex and electrical stimulation of the femoral nerve. The age-related loss in power was ~6.5 W·year-1 for men (R2=0.62, p<0.001), which was a greater rate of decline (p=0.002) than the ~4.2 W·year-1 for women (R2=0.77, p<0.001). Contractile properties were the most closely associated variables with power output for both sexes, such as the rate of torque development of the potentiated twitch (men: R2=0.69, p<0.001; women: R2=0.57, p<0.001). VA was weakly associated with power in women (R2=0.13, p=0.012) but not men (p=0.191), whereas neuromuscular activation (EMG amplitude) during the maximal power contraction was not associated with power in men (p=0.347) or women (p=0.106). These data suggest that the age-related loss in power of the knee extensor muscles is due primarily to factors within the muscle for both sexes, although neural factors may play a minor role in older women.
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Affiliation(s)
- David J. Wrucke
- Exercise and Rehabilitation Sciences Program, Department of Physical Therapy, Marquette University, Milwaukee, WI, USA
| | - Andrew Kuplic
- Exercise and Rehabilitation Sciences Program, Department of Physical Therapy, Marquette University, Milwaukee, WI, USA
| | - Mitchell Adam
- Exercise and Rehabilitation Sciences Program, Department of Physical Therapy, Marquette University, Milwaukee, WI, USA
| | - Sandra K. Hunter
- Exercise and Rehabilitation Sciences Program, Department of Physical Therapy, Marquette University, Milwaukee, WI, USA
- Athletic and Human Performance Research Center, Marquette University, Milwaukee, WI, USA
| | - Christopher W. Sundberg
- Exercise and Rehabilitation Sciences Program, Department of Physical Therapy, Marquette University, Milwaukee, WI, USA
- Athletic and Human Performance Research Center, Marquette University, Milwaukee, WI, USA
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Varesco G, Luneau E, Millet GY, Féasson L, Lapole T, Rozand V. Age-Related Differences between Old and Very Old Men in Performance and Fatigability Are Evident after Cycling but Not Isometric or Concentric Single-Limb Tasks. Med Sci Sports Exerc 2023; 55:1641-1650. [PMID: 37580874 DOI: 10.1249/mss.0000000000003181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/16/2023]
Abstract
PURPOSE This study aimed to compare performance and fatigability between young (n = 13; 18-30 yr), old (n = 13; 60-80 yr), and very old (n = 12; >80 yr) men during a single-joint isometric (ISO) and concentric (CON) task performed on an isokinetic dynamometer and a cycling (BIKE) task. METHODS Participants randomly performed incremental tasks consisting of stages of 75 contractions (i.e., 120 s, 0.8 s on/0.8 s off) for ISO and CON and 120 s at 37.5 rpm (similar duty cycle) for BIKE. Increments were set as a percentage of body weight. Knee extensor maximal force, voluntary activation, and twitch amplitude were measured at baseline, after each stage, and at task failure (five out of eight contractions below the target force or 6 s in a row at a cadence <37.5 rpm). RESULTS Compared with young men, performance (number of stages) was 24% and 40% lower in old and very old men in ISO, 54% and 59% lower in CON, and 36% and 60% lower in BIKE (all P < 0.05). Performance of old and very old differed only in BIKE (P < 0.01). For the last common stages performed, compared with young, force loss was greater for very old men in ISO and for old and very old men in BIKE (all P < 0.05). Overall, for the last common stage performed and task failure, old and very old men presented similar force loss, alterations in voluntary activation, and twitch amplitude. CONCLUSIONS Our findings reveal that, with workloads relative to body weight, differences in performance between old and very old men could only be observed during BIKE (i.e., the more ecologically valid task). Results from isometric or concentric conditions might not be transferable to dynamic exercise with large muscle masses.
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Affiliation(s)
- Giorgio Varesco
- Université Jean Monnet Saint-Etienne, Lyon 1, Université Savoie Mont-Blanc, Laboratoire Interuniversitaire de Biologie de la Motricité, F-42023, Saint-Etienne, FRANCE
| | - Eric Luneau
- Université Jean Monnet Saint-Etienne, Lyon 1, Université Savoie Mont-Blanc, Laboratoire Interuniversitaire de Biologie de la Motricité, F-42023, Saint-Etienne, FRANCE
| | | | | | - Thomas Lapole
- Université Jean Monnet Saint-Etienne, Lyon 1, Université Savoie Mont-Blanc, Laboratoire Interuniversitaire de Biologie de la Motricité, F-42023, Saint-Etienne, FRANCE
| | - Vianney Rozand
- Université Jean Monnet Saint-Etienne, Lyon 1, Université Savoie Mont-Blanc, Laboratoire Interuniversitaire de Biologie de la Motricité, F-42023, Saint-Etienne, FRANCE
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7
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Zoughaib WS, Hoffman RL, Yates BA, Moorthi RN, Lim K, Coggan AR. The influence of acute dietary nitrate supplementation on skeletal muscle fatigue and recovery in older women. Physiol Rep 2023; 11:e15694. [PMID: 37226336 PMCID: PMC10209430 DOI: 10.14814/phy2.15694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 05/05/2023] [Accepted: 05/06/2023] [Indexed: 05/26/2023] Open
Abstract
Older individuals fatigue more rapidly during, and recover more slowly from, dynamic exercise. Women are particularly vulnerable to these deleterious effects of aging, which increases their risk of falling. We have shown that dietary nitrate (NO3 - ), a source of nitric oxide (NO) via the NO3 - → nitrite (NO2 - ) → NO pathway, enhances muscle speed and power in older individuals in the non-fatigued state; however, it is unclear if it reduces fatigability and/or improves recoverability in this population. Using a double-blind, placebo-controlled, crossover design, we studied 18 older (age 70 ± 4 years) women who were administered an acute dose of beetroot juice (BRJ) containing either 15.6 ± 3.6 or <0.05 mmol of NO3 - . Blood samples were drawn throughout each ~3 h visit for plasma NO3 - and NO2 - analysis. Peak torque was measured during, and periodically for 10 min after, 50 maximal knee extensions performed at 3.14 rad/s on an isokinetic dynamometer. Ingestion of NO3 - -containing BRJ increased plasma NO3 - and NO2 - concentrations by 21 ± 8 and 4 ± 4 fold, respectively. However, there were no differences in muscle fatigue or recovery. Dietary NO3 - increases plasma NO3 - and NO2 - concentrations but does not reduce fatigability during or enhance recoverability after high intensity exercise in older women.
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Affiliation(s)
- William S. Zoughaib
- Department of Kinesiology, School of Health & Human SciencesIndiana University Purdue University IndianapolisIndianapolisIndianaUSA
| | - Richard L. Hoffman
- Department of Kinesiology, School of Health & Human SciencesIndiana University Purdue University IndianapolisIndianapolisIndianaUSA
| | - Brandon A. Yates
- Indiana Center for Musculoskeletal HealthIndiana University School of MedicineIndianapolisIndianaUSA
| | - Ranjani N. Moorthi
- Division of Nephrology and Hypertension, Department of MedicineIndiana University School of MedicineIndianapolisIndianaUSA
| | - Kenneth Lim
- Division of Nephrology and Hypertension, Department of MedicineIndiana University School of MedicineIndianapolisIndianaUSA
| | - Andrew R. Coggan
- Department of Kinesiology, School of Health & Human SciencesIndiana University Purdue University IndianapolisIndianapolisIndianaUSA
- Indiana Center for Musculoskeletal HealthIndiana University School of MedicineIndianapolisIndianaUSA
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Boyer KA, Hayes KL, Umberger BR, Adamczyk PG, Bean JF, Brach JS, Clark BC, Clark DJ, Ferrucci L, Finley J, Franz JR, Golightly YM, Hortobágyi T, Hunter S, Narici M, Nicklas B, Roberts T, Sawicki G, Simonsick E, Kent JA. Age-related changes in gait biomechanics and their impact on the metabolic cost of walking: Report from a National Institute on Aging workshop. Exp Gerontol 2023; 173:112102. [PMID: 36693530 PMCID: PMC10008437 DOI: 10.1016/j.exger.2023.112102] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 01/09/2023] [Accepted: 01/19/2023] [Indexed: 01/22/2023]
Abstract
Changes in old age that contribute to the complex issue of an increased metabolic cost of walking (mass-specific energy cost per unit distance traveled) in older adults appear to center at least in part on changes in gait biomechanics. However, age-related changes in energy metabolism, neuromuscular function and connective tissue properties also likely contribute to this problem, of which the consequences are poor mobility and increased risk of inactivity-related disease and disability. The U.S. National Institute on Aging convened a workshop in September 2021 with an interdisciplinary group of scientists to address the gaps in research related to the mechanisms and consequences of changes in mobility in old age. The goal of the workshop was to identify promising ways to move the field forward toward improving gait performance, decreasing energy cost, and enhancing mobility for older adults. This report summarizes the workshop and brings multidisciplinary insight into the known and potential causes and consequences of age-related changes in gait biomechanics. We highlight how gait mechanics and energy cost change with aging, the potential neuromuscular mechanisms and role of connective tissue in these changes, and cutting-edge interventions and technologies that may be used to measure and improve gait and mobility in older adults. Key gaps in the literature that warrant targeted research in the future are identified and discussed.
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Affiliation(s)
- Katherine A Boyer
- Department of Kinesiology, University of Massachusetts Amherst, MA, USA; Department of Orthopedics and Physical Rehabilitation, University of Massachusetts Medical School, Worcester, MA, USA.
| | - Kate L Hayes
- Department of Kinesiology, University of Massachusetts Amherst, MA, USA
| | | | | | - Jonathan F Bean
- New England GRECC, VA Boston Healthcare System, Boston, MA, USA; Department of PM&R, Harvard Medical School, Boston, MA, USA; Spaulding Rehabilitation Hospital, Boston, MA, USA
| | - Jennifer S Brach
- Department of Physical Therapy, University of Pittsburgh, Pittsburgh, PA, USA
| | - Brian C Clark
- Ohio Musculoskeletal and Neurological Institute and the Department of Biomedical Sciences, Ohio University, Athens, OH, USA
| | - David J Clark
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, Gainesville, FL, USA; Department of Physiology and Aging, University of Florida, Gainesville, FL, USA
| | - Luigi Ferrucci
- Intramural Research Program of the National Institute on Aging, NIH, Baltimore, MD, USA
| | - James Finley
- Division of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, CA, USA
| | - Jason R Franz
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, NC, USA
| | - Yvonne M Golightly
- College of Allied Health Professions, University of Nebraska Medical Center, Omaha, NE, USA; Thurston Arthritis Research Center, Division of Rheumatology, Allergy, and Immunology, Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Tibor Hortobágyi
- Hungarian University of Sports Science, Department of Kinesiology, Budapest, Hungary; Institute of Sport Sciences and Physical Education, University of Pécs, Hungary; Somogy County Kaposi Mór Teaching Hospital, Kaposvár, Hungary; Center for Human Movement Sciences, University of Groningen Medical Center, Groningen, the Netherlands
| | - Sandra Hunter
- Department of Physical Therapy, Marquette University, Milwaukee, WI, USA
| | - Marco Narici
- Neuromuscular Physiology Laboratory, Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Barbara Nicklas
- Section on Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, USA
| | - Thomas Roberts
- Department of Ecology and Evolutionary Biology, Brown University, USA
| | - Gregory Sawicki
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, USA
| | - Eleanor Simonsick
- Intramural Research Program of the National Institute on Aging, NIH, Baltimore, MD, USA
| | - Jane A Kent
- Department of Kinesiology, University of Massachusetts Amherst, MA, USA
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Zoughaib WS, Hoffman RL, Yates BA, Moorthi RN, Lim K, Coggan AR. The influence of acute dietary nitrate supplementation on skeletal muscle fatigue and recovery in older women. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.02.15.23285957. [PMID: 36824817 PMCID: PMC9949194 DOI: 10.1101/2023.02.15.23285957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Older individuals fatigue more rapidly during, and recover more slowly from, dynamic exercise. Women are particularly vulnerable to these deleterious effects of aging, which increases their risk of falling. We have shown that dietary nitrate (NO 3 - ), a source of nitric oxide (NO) via the NO 3 - → nitrite (NO 2 - ) → NO pathway, enhances muscle speed and power in older individuals in the non-fatigued state; however, it is unclear if it reduces fatigability and/or improves recoverability in this population. Using a double-blind, placebo-controlled, crossover design, we studied 18 older (age 70 ± 4 y) women who were administered an acute dose of beetroot juice (BRJ) containing either 15.6±3.6 or <0.05 mmol of NO 3 - . Blood samples were drawn throughout each ∼3 h visit for plasma NO 3 - and NO 2 - analysis. Peak torque was measured during, and periodically for 10 min after, 50 maximal knee extensions performed at 3.14 rad/s on an isokinetic dynamometer. Ingestion of NO 3 - -containing BRJ increased plasma NO 3 - and NO 2 - concentrations by 21±8 and 4±4 fold, respectively. However, there were no differences in muscle fatigue or recovery. Dietary NO 3 - increases plasma NO 3 - and NO 2 - concentrations but does not reduce fatigability during or enhance recoverability after high intensity exercise in older women.
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10
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Alcazar J, Rodriguez-Lopez C, Delecluse C, Thomis M, Van Roie E. Ten-year longitudinal changes in muscle power, force, and velocity in young, middle-aged, and older adults. J Cachexia Sarcopenia Muscle 2023; 14:1019-1032. [PMID: 36788413 PMCID: PMC10067493 DOI: 10.1002/jcsm.13184] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 12/05/2022] [Accepted: 01/11/2023] [Indexed: 02/16/2023] Open
Abstract
BACKGROUND Maximum muscle power (Pmax ) is a biomarker of physical performance in all ages. No longitudinal studies have assessed the effects of aging on Pmax obtained from the torque-velocity (T-V) relationship, which should be considered the 'gold standard'. This study evaluated the longitudinal changes in the T-V relationship and Pmax of the knee-extensor muscles in young, middle-aged, and older adults after 10 years of follow-up. METHODS Four hundred eighty-nine subjects (311 men and 178 women; aged 19-68 years) were tested at baseline and after a 10-year follow-up. Anthropometric data, daily protein intake, physical activity level (PAL), and knee-extension muscle function (isometric, isokinetic, and isotonic) were evaluated. A novel hybrid equation combining a linear and a hyperbolic (Hill-type) region was used to obtain the T-V relationship and Pmax of the participants, who were grouped by sex and age (young: 20-40 years; middle-aged: 40-60 years; and old: ≥60 years). Linear mixed-effect models were used to assess effects of time, sex, and age on T-V parameters, Pmax , and body mass index (BMI). Additional analyses were performed to adjust for changes in daily protein intake and PAL. RESULTS Pmax decreased in young men (-0.6% per year; P < 0.001), middle-aged men and women (-1.1% to -1.4% per year; P < 0.001), and older men and women (-2.2% to -2.4% per year; P ≤ 0.053). These changes were mainly related to decrements in torque at Pmax at early age and to decrements in both torque and velocity at Pmax at older age. BMI increased among young and middle-aged adults (0.2% to 0.5% per year; P < 0.001), which led to greater declines in relative Pmax in those groups. S/T0 , that is, the linear slope of the T-V relationship relative to maximal torque, exhibited a significant decline over time (-0.10%T0 ·rad·s-1 per year; P < 0.001), which was significant among middle-aged men and old men and women (all P < 0.05). Annual changes in PAL index were significantly associated to annual changes in Pmax (P = 0.017), so the overall decline in Pmax was slightly attenuated in the adjusted model (-5.26 vs. -5.05 W per year; both P < 0.001). CONCLUSIONS Pmax decreased in young, middle-aged, and older adults after a 10-year follow-up. The early declines in Pmax seemed to coincide with declines in force, whereas the progressive decline at later age was associated with declines in both force and velocity. A progressively blunted ability to produce force, especially at moderate to high movement velocities, should be considered a specific hallmark of aging.
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Affiliation(s)
- Julian Alcazar
- GENUD Toledo Research Group, Universidad de Castilla-La Mancha, Toledo, Spain.,CIBER of Frailty and Healthy Aging (CIBERFES), Madrid, Spain
| | - Carlos Rodriguez-Lopez
- GENUD Toledo Research Group, Universidad de Castilla-La Mancha, Toledo, Spain.,CIBER of Frailty and Healthy Aging (CIBERFES), Madrid, Spain
| | - Christophe Delecluse
- Physical Activity, Sports and Health Research Group, Department of Movement Sciences, KU Leuven, Leuven, Belgium
| | - Martine Thomis
- Physical Activity, Sports and Health Research Group, Department of Movement Sciences, KU Leuven, Leuven, Belgium
| | - Evelien Van Roie
- Physical Activity, Sports and Health Research Group, Department of Movement Sciences, KU Leuven, Leuven, Belgium
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11
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Paris MT, McNeil CJ, Power GA, Rice CL, Dalton BH. Age-related performance fatigability: a comprehensive review of dynamic tasks. J Appl Physiol (1985) 2022; 133:850-866. [PMID: 35952347 DOI: 10.1152/japplphysiol.00319.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Adult ageing is associated with a myriad of changes within the neuromuscular system, leading to reductions in contractile function of old adults. One of the consequences of these age-related neuromuscular adaptations is altered performance fatigability, which can limit the ability of old adults to perform activities of daily living. Whereas age-related fatigability of isometric tasks has been well characterized, considerably less is known about fatigability of old adults during dynamic tasks involving movement about a joint, which provides a more functionally relevant task compared to static contractions. This review provides a comprehensive summary of age-related fatigability in dynamic contractions, where the importance of task specificity is highlighted with a brief discussion of the potential mechanisms responsible for differences in fatigability between young and old adults. The angular velocity of the task is critical for evaluating age-related fatigability, as tasks which constrain angular velocity (i.e., isokinetic) produce equivocal age-related differences in fatigability, whereas tasks involving unconstrained velocity (i.e., isotonic-like) consistently induce greater fatigability of old compared to young adults. These unconstrained velocity tasks, that are more closely associated with natural movements, offer an excellent model to uncover the underlying age-related mechanisms of increased fatigability. Future work evaluating the mechanisms of increased age-related fatigability of dynamic tasks should be evaluated using task-specific contractions (i.e., dynamic), particularly for assessment of spinal and supra-spinal components. Advancing our understanding of age-related fatigability is likely to yield novel insights and approaches for improving mobility limitations in old adults.
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Affiliation(s)
- Michael T Paris
- School of Kinesiology, University of Western Ontario, London, ON, Canada
| | - Chris J McNeil
- School of Health and Exercise Science, University of British Columbia, Kelowna, BC, Canada
| | - Geoffrey A Power
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
| | - Charles L Rice
- School of Kinesiology, University of Western Ontario, London, ON, Canada.,Department of Anatomy and Cell Biology, University of Western Ontario, London, ON, Canada
| | - Brian H Dalton
- School of Health and Exercise Science, University of British Columbia, Kelowna, BC, Canada
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12
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Verschueren A, Palminha C, Delmont E, Attarian S. Changes in neuromuscular function in elders: Novel techniques for assessment of motor unit loss and motor unit remodeling with aging. Rev Neurol (Paris) 2022; 178:780-787. [PMID: 35863917 DOI: 10.1016/j.neurol.2022.03.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/08/2022] [Accepted: 03/08/2022] [Indexed: 11/24/2022]
Abstract
Functional muscle fiber denervation is a major contributor to the decline in physical function observed with aging and is now a recognized cause of sarcopenia, a muscle disorder characterized by progressive and generalized degenerative loss of skeletal muscle mass, quality, and strength. There is an interrelationship between muscle strength, motor unit (MU) number, and aging, which suggests that a portion of muscle weakness in seniors may be attributable to the loss of functional MUs. During normal aging, there is a time-related progression of MU loss, an adaptive sprouting followed by a maladaptive sprouting, and continuing recession of terminal Schwann cells leading to a reduced capacity for compensatory reinnervation in elders. In amyotrophic lateral sclerosis, increasing age at onset predicts worse survival ALS and it is possible that age-related depletion of the motor neuron pool may worsen motor neuron disease. MUNE methods are used to estimate the number of functional MU, data from MUNIX arguing for motor neuron loss with aging will be reviewed. Recently, a new MRI technique MU-MRI could be used to assess the MU recruitment or explore the activity of a single MU. This review presents published studies on the changes of neuromuscular function with aging, then focusing on these two novel techniques for assessment of MU loss and MU remodeling.
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Affiliation(s)
- A Verschueren
- Reference Centre for Neuromuscular Disorders and ALS, CHU La Timone, Aix-Marseille University, 264, rue Saint Pierre, 13005 Marseille, France.
| | - C Palminha
- Reference Centre for Neuromuscular Disorders and ALS, CHU La Timone, Aix-Marseille University, 264, rue Saint Pierre, 13005 Marseille, France
| | - E Delmont
- Reference Centre for Neuromuscular Disorders and ALS, CHU La Timone, Aix-Marseille University, 264, rue Saint Pierre, 13005 Marseille, France
| | - S Attarian
- Reference Centre for Neuromuscular Disorders and ALS, CHU La Timone, Aix-Marseille University, 264, rue Saint Pierre, 13005 Marseille, France
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13
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Ha PL, Peters WB, McGeehan MA, Dalton BH. Age-related reduction in peak power and increased postural displacement variability are related to enhanced vestibular-evoked balance responses in females. Exp Gerontol 2022; 160:111670. [PMID: 35026336 DOI: 10.1016/j.exger.2021.111670] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 12/11/2021] [Accepted: 12/15/2021] [Indexed: 11/04/2022]
Abstract
Adult aging is associated with reductions in muscle function and standing balance control. However, whether sensorimotor function adapts to maintain upright posture in the presence of age-related muscle weakness is unclear. The purpose was to determine whether vestibular control of balance is altered in older compared to younger females and whether vestibular-evoked balance responses are related to muscle power. Eight young (22.6 ± 1.8 years) and eight older (69.7 ± 6.7 years) females stood quietly on a force plate, while subjected to random, continuous electrical vestibular stimulation (EVS; 0-20 Hz, root mean square amplitude: 1.13 mA). Medial gastrocnemius (MG) and tibialis anterior (TA) surface electromyography (EMG) and force plate anterior-posterior (AP) forces were sampled and associated with the EVS signal in the frequency and time domains. Knee extensor function was evaluated using a Biodex multi-joint dynamometer. The weaker, less powerful older females exhibited a 99 and 42% greater medium-latency peak amplitude for the TA and AP force (p < 0.05), respectively, but no other differences were detected for short- and medium-latency peak amplitudes. The TA (<10 Hz) and MG (<4 Hz) EVS-EMG coherence and EVS-AP force coherence (<2 Hz) was greater in older females than young. A strong correlation was detected for AP force medium-latency peak amplitude with center of pressure displacement variability (r = 0.75; p < 0.05) and TA medium-latency peak amplitude (r = 0.86; p < 0.05). Power was negatively correlated with AP force medium-latency peak amplitude (r = -0.47; p < 0.05). Taken together, an increased vestibular control of balance may compensate for an age-related reduction in power and accompanies greater postural instability in older females than young.
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Affiliation(s)
- Phuong L Ha
- School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Wendy B Peters
- Department of Human Physiology, University of Oregon, Eugene, OR, United States
| | - Michael A McGeehan
- Department of Human Physiology, University of Oregon, Eugene, OR, United States
| | - Brian H Dalton
- School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada; Department of Human Physiology, University of Oregon, Eugene, OR, United States.
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14
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Wu R, De Vito G, Lowery MM, O'Callaghan B, Ditroilo M. Age-related fatigability in knee extensors and knee flexors during dynamic fatiguing contractions. J Electromyogr Kinesiol 2021; 62:102626. [PMID: 34998161 DOI: 10.1016/j.jelekin.2021.102626] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 11/08/2021] [Accepted: 12/14/2021] [Indexed: 12/01/2022] Open
Abstract
This study investigated the effects of dynamic knee extension and flexion fatiguing task on torque and neuromuscular responses in young and older individuals. Eighteen young (8 males; 25.1 ± 3.2 years) and 17 older (8 males; 69.7 ± 3.7 years) volunteered. Following a maximal voluntary isometric contraction test, participants performed a fatiguing task involving 22 maximal isokinetic (concentric) knee extension and flexion contractions at 60°/s, while surface EMG was recorded simultaneously from the knee extensors (KE) and flexors (KF). Fatigue-induced relative torque reductions were similar between age groups for KE (peak torque decrease: 25.15% vs 26.81%); however, KF torque was less affected in older individuals (young vs older peak torque decrease: 27.6% vs 11.5%; p < 0.001) and this was associated with greater increase in hamstring EMG amplitude (p < 0.001) and hamstrings/quadriceps peak torque ratio (p < 0.01). Furthermore, KE was more fatigable than KF only among older individuals (peak torque decrease: 26.8% vs 11.5%; p < 0.001). These findings showed that the age-related fatigue induced by a dynamic task was greater for the KE, with greater age-related decline in KE compared to KF.
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Affiliation(s)
- Rui Wu
- School of Electrical & Electronic Engineering, University College Dublin, Dublin, Ireland; School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland
| | - Giuseppe De Vito
- School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland; Biomedical Sciences Department, Neuromuscular Physiology Laboratory, University of Padova, Italy
| | - Madeleine M Lowery
- School of Electrical & Electronic Engineering, University College Dublin, Dublin, Ireland
| | - Ben O'Callaghan
- School of Electrical & Electronic Engineering, University College Dublin, Dublin, Ireland
| | - Massimiliano Ditroilo
- School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland
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15
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Delgadillo JD, Sundberg CW, Kwon M, Hunter SK. Fatigability of the knee extensor muscles during high-load fast and low-load slow resistance exercise in young and older adults. Exp Gerontol 2021; 154:111546. [PMID: 34492255 DOI: 10.1016/j.exger.2021.111546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 08/08/2021] [Accepted: 08/26/2021] [Indexed: 10/20/2022]
Abstract
Resistance exercise training is a cornerstone in preventing age-related declines in muscle mass and strength, and fatigability of limb muscle is important to this adaptive response. It is unknown, however, whether fatigability and the underlying mechanisms differ between different resistance exercise protocols in young and older adults. The purpose of this study was to quantify the fatigability of the knee extensors and identify the mechanisms in 20 young (22.2 ± 1.3 yr, 10 women) and 20 older adults (73.8 ± 5.4 yr, 10 women) elicited by a single session of high- and low-load resistance exercise. One leg completed a high-load protocol with contractions performed as fast as possible (HL-fast, ~80% 1 Repetition Max, 1RM), and the contralateral leg a low-load protocol performed with slow contractions (LL-slow, ~30% 1RM, 6 s concentric, 6 s eccentric). Each exercise involved four sets of eight repetitions. Before and immediately following each set, maximal voluntary isometric contractions (MVC) were performed, and voluntary activation and contractile properties quantified using electrical stimulation. The reduction in MVC was greater following the LL-slow (20%) than the HL-fast (12%, P = 0.004), with no age or sex differences. Similarly, the reduction in the amplitude of the involuntary electrically-evoked twitch was greater in the LL-slow (14%) than the HL-fast (7%, P = 0.014) and correlated with the reduction in MVC (r = 0.546, P < 0.001), whereas voluntary activation decreased only for the LL-slow protocol (5%, P < 0.001). Thus, low-load resistance exercise with slow contractions induced greater fatigability within the muscle than a more traditional high-load resistance protocol for both young and older men and women.
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Affiliation(s)
- Jose D Delgadillo
- Exercise Science Program, Department of Physical Therapy, Marquette University, Milwaukee, WI, USA
| | - Christopher W Sundberg
- Exercise Science Program, Department of Physical Therapy, Marquette University, Milwaukee, WI, USA; Athletic and Human Performance Research Center, Marquette University, Milwaukee, WI, USA
| | - Minhyuk Kwon
- Exercise Science Program, Department of Physical Therapy, Marquette University, Milwaukee, WI, USA; Department of Kinesiology & Health Promotion, California State Polytechnic University, Pomona, CA, USA
| | - Sandra K Hunter
- Exercise Science Program, Department of Physical Therapy, Marquette University, Milwaukee, WI, USA; Athletic and Human Performance Research Center, Marquette University, Milwaukee, WI, USA.
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16
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Rakshit R, Xiang Y, Yang J. Functional muscle group- and sex-specific parameters for a three-compartment controller muscle fatigue model applied to isometric contractions. J Biomech 2021; 127:110695. [PMID: 34454329 DOI: 10.1016/j.jbiomech.2021.110695] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 08/10/2021] [Accepted: 08/12/2021] [Indexed: 02/06/2023]
Abstract
The three-compartment controller with enhanced recovery (3CC-r) model of muscle fatigue has previously been validated separately for both sustained (SIC) and intermittent isometric contractions (IIC) using different objective functions, but its performance has not yet been tested against both contraction types simultaneously using a common objective function. Additionally, prior validation has been performed using common parameters at the joint level, whereas applications to many real-world tasks will require the model to be applied to agonistic and synergistic muscle groups. Lastly, parameters for the model have previously been derived for a mixed-sex cohort not considering the differece in fatigabilities between the sexes. In this work we validate the 3CC-r model using a comprehensive isometric contraction database drawn from 172 publications segregated by functional muscle group (FMG) and sex. We find that prediction errors are reduced by 19% on average when segregating the dataset by FMG alone, and by 34% when segregating by both sex and FMG. However, minimum prediction errors are found to be higher when validated against both SIC and IIC data together using torque decline as the outcome variable than when validated sequentially against hypothesized SIC intensity-endurance time curves with endurance time as the outcome variable and against raw IIC data with torque decline as the outcome variable.
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Affiliation(s)
- Ritwik Rakshit
- Human-Centric Design Research Lab, Department of Mechanical Engineering, Texas Tech University, Lubbock, TX 79409, USA
| | - Yujiang Xiang
- School of Mechanical and Aerospace Engineering, Oklahoma State University, Stillwater, OK 74078, USA
| | - James Yang
- Human-Centric Design Research Lab, Department of Mechanical Engineering, Texas Tech University, Lubbock, TX 79409, USA.
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17
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Sadri S, Sharifi G, Jalali Dehkordi K. Nano branched-chain amino acids enhance the effect of uphill (concentric) and downhill (eccentric) treadmill exercise on muscle gene expression of Akt and mTOR on aged rats. SPORT SCIENCES FOR HEALTH 2021. [DOI: 10.1007/s11332-021-00828-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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18
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Senefeld JW, Keenan KG, Ryan KS, D'Astice SE, Negro F, Hunter SK. Greater fatigability and motor unit discharge variability in human type 2 diabetes. Physiol Rep 2021; 8:e14503. [PMID: 32633071 PMCID: PMC7379048 DOI: 10.14814/phy2.14503] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
This study determined the discharge characteristics of motor units from two lower limb muscles before and after fatiguing exercise in people with type 2 diabetes (T2D) with no symptoms of polyneuropathy and activity‐matched controls. Seventeen people with T2D (65.0 ± 5.6 years; 8 women) and 17 controls (63.6 ± 4.5 years; 8 women) performed: (a) intermittent, isometric contractions at 50% maximal voluntary isometric contraction (MVIC) sustained to failure with the ankle dorsiflexors, and (b) a dynamic fatiguing task (30% MVIC load) for 6 min with the knee extensors. Before and after the fatiguing tasks, motor unit characteristics (including coefficient of variation (CV) of interspike intervals (ISI)) were quantified from high‐density electromyography and muscle contractile properties were assessed via electrical stimulation. Fatigability was ~50% greater for people with T2D than controls for the dorsiflexors (time‐to‐failure: 7.3 ± 4.1 vs. 14.3 ± 9.1 min, p = .010) and knee extensors (power reduction: 56.7 ± 11.9 vs. 31.5 ± 25.5%, p < .001). The CV of ISI was greater for the T2D than control group for the tibialis anterior (23.1 ± 11.0 vs. 21.3 ± 10.7%, p < .001) and vastus lateralis (27.8 ± 20.2 vs. 24.5 ± 16.1%, p = .011), but these differences did not change after the fatiguing exercises. People with T2D had greater reductions in the electrically evoked twitch amplitude of the dorsiflexors (8.5 ± 5.1 vs. 4.0 ± 3.4%·min‐1, p = .013) and knee extensors (49.1 ± 10.0 vs. 31.8 ± 15.9%, p = .004) than controls. Although motor unit activity was more variable in people with T2D than controls, the greater fatigability of the T2D group for lower limb muscles was due to mechanisms involving disruption of contractile function of the exercising muscles rather than motor unit behavior.
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Affiliation(s)
- Jonathon W Senefeld
- Exercise Science Program, Marquette University, Milwaukee, WI, USA.,Department of Physical Therapy, Marquette University, Milwaukee, WI, USA.,Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, USA
| | - Kevin G Keenan
- Department of Kinesiology, University of Wisconsin, Milwaukee, WI, USA.,Center for Aging and Translational Research, University of Wisconsin, Milwaukee, WI, USA
| | - Kevin S Ryan
- Exercise Science Program, Marquette University, Milwaukee, WI, USA.,Department of Physical Therapy, Marquette University, Milwaukee, WI, USA
| | - Sarah E D'Astice
- Exercise Science Program, Marquette University, Milwaukee, WI, USA.,Department of Physical Therapy, Marquette University, Milwaukee, WI, USA
| | - Francesco Negro
- Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy
| | - Sandra K Hunter
- Exercise Science Program, Marquette University, Milwaukee, WI, USA.,Department of Physical Therapy, Marquette University, Milwaukee, WI, USA
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19
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Fitzgerald LF, Bartlett MF, Nagarajan R, Francisco EJ, Sup FC, Kent JA. Effects of old age and contraction mode on knee extensor muscle ATP flux and metabolic economy in vivo. J Physiol 2021; 599:3063-3080. [PMID: 33876434 DOI: 10.1113/jp281117] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 04/14/2021] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS We used 31-phosphorus magnetic resonance spectroscopy to quantify in vivo skeletal muscle metabolic economy (ME; mass-normalized torque or power produced per ATP consumed) during three 24 s maximal-effort contraction protocols: (1) sustained isometric (MVIC), (2) intermittent isokinetic (MVDCIsoK ), and (3) intermittent isotonic (MVDCIsoT ) in the knee extensor muscles of young and older adults. ME was not different between groups during the MVIC but was lower in older than young adults during both dynamic contraction protocols. These results are consistent with an increased energy cost of locomotion, but not postural support, with age. The effects of old age on ME were not due to age-related changes in muscle oxidative capacity or ATP flux. Specific power was lower in older than young adults, despite similar total ATP synthesis between groups. Together, this suggests a dissociation between cross-bridge activity and ATP utilization with age. ABSTRACT Muscle metabolic economy (ME; mass-normalized torque or power produced per ATP consumed) is similar in young and older adults during some isometric contractions, but less is known about potential age-related differences in ME during dynamic contractions. We hypothesized that age-related differences in ME would exist only during dynamic contractions, due to the increased energetic demand of dynamic versus isometric contractions. Ten young (Y; 27.5 ± 3.9 years, 6 men) and 10 older (O; 71 ± 5 years, 5 men) healthy adults performed three 24 s bouts of maximal contractions: (1) sustained isometric (MVIC), (2) isokinetic (120°·s-1 , MVDCIsoK ; 0.5 Hz), and (3) isotonic (load = 20% MVIC, MVDCIsoT ; 0.5 Hz). Phosphorus magnetic resonance spectroscopy of the vastus lateralis muscle was used to calculate ATP flux (mM ATP·s-1 ) through the creatine kinase reaction, glycolysis and oxidative phosphorylation. Quadriceps contractile volume (cm3 ) was measured by MRI. ME was calculated using the torque-time integral (MVIC) or power-time integral (MVDCIsoK and MVDCIsoT ), total ATP synthesis and contractile volume. As hypothesized, ME was not different between Y and O during the MVIC (0.12 ± 0.03 vs. 0.12 ± 0.02 Nm. s. cm-3 . mM ATP-1 , mean ± SD, respectively; P = 0.847). However, during both MVDCIsoK and MVDCIsoT , ME was lower in O than Y adults (MVDCIsoK : 0.011 ± 0.003 vs. 0.007 ± 0.002 J. cm-3 . mM ATP-1 ; P < 0.001; MVDCIsoT : 0.011 ± 0.002 vs. 0.008 ± 0.002; P = 0.037, respectively), despite similar muscle oxidative capacity, oxidative and total ATP flux in both groups. The lower specific power in older than young adults, despite similar total ATP synthesis between groups, suggests there is a dissociation between cross-bridge activity and ATP utilization with age.
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Affiliation(s)
- Liam F Fitzgerald
- Muscle Physiology Laboratory, Department of Kinesiology, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Miles F Bartlett
- Muscle Physiology Laboratory, Department of Kinesiology, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Rajakumar Nagarajan
- Human Magnetic Resonance Center, Institute for Applied Life Sciences, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Ericber Jimenez Francisco
- Mechatronics and Robotics Laboratory, Department of Mechanical & Industrial Engineering, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Frank C Sup
- Mechatronics and Robotics Laboratory, Department of Mechanical & Industrial Engineering, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Jane A Kent
- Muscle Physiology Laboratory, Department of Kinesiology, University of Massachusetts Amherst, Amherst, MA, 01003, USA
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20
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Rodriguez-Lopez C, Alcazar J, Losa-Reyna J, Carmona-Torres J, Cruz-Santaella AM, Ara I, Csapo R, Alegre LM. Acute Physiological Response to Light- and Heavy-load Power-oriented Exercise in Older Adults. Int J Sports Med 2021; 42:1287-1296. [PMID: 33902152 DOI: 10.1055/a-1408-4793] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
This study investigated the acute responses to volume-load-matched heavy-load (80% 1RM) versus light-load (40% 1RM) power-oriented resistance training sessions in well-functioning older adults. Using a randomized cross-over design, 15 volunteers completed each condition on a leg press. Neuromuscular (maximal isometric force and rate of force development) and functional performance (power during sit-to-stand test), lactate, and muscle damage biochemistry (creatine kinase, lactate dehydrogenase and C-reactive protein serum concentration) were assessed pre- and post-exercise. Performance declines were found after heavy-load (Cohen's d effect size (d); maximal isometric force=0.95 d; rate of force development=1.17 d; sit-to-stand power =0.38 d, all p<0.05) and light-load (maximal isometric force=0.45 d; rate of force development=0.9 d; sit-to-stand power=1.17 d, all p<0.05), while lactate concentration increased only after light-load (1.7 d, p=0.001). However, no differences were found between conditions (all p>0.05). Both conditions increased creatine kinase the day after exercise (marginal effect=0.75 d, p<0.001), but no other blood markers increased (all, p>0.05). Irrespective of the load used, power training induced non-clinically significant decreases in sit-to-stand performance, moderate declines in maximal isometric force, but pronounced decreases in the rate of force development. Furthermore, the metabolic stress and muscle damage were minor; both sessions were generally well tolerated by well-functioning older adults without previous experience in resistance training.
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Affiliation(s)
- Carlos Rodriguez-Lopez
- GENUD Toledo Research Group, Universidad de Castilla-La Mancha, Toledo, Spain.,CIBER of Frailty and Healthy Aging (CIBERFES), Madrid, Spain
| | - Julian Alcazar
- GENUD Toledo Research Group, Universidad de Castilla-La Mancha, Toledo, Spain.,CIBER of Frailty and Healthy Aging (CIBERFES), Madrid, Spain
| | - Jose Losa-Reyna
- GENUD Toledo Research Group, Universidad de Castilla-La Mancha, Toledo, Spain.,CIBER of Frailty and Healthy Aging (CIBERFES), Madrid, Spain.,Department of Geriatrics, Hospital Virgen del Valle, Complejo Hospitalario de Toledo, Toledo, Spain
| | | | | | - Ignacio Ara
- CIBER of Frailty and Healthy Aging (CIBERFES), Madrid, Spain.,CIBER of Frailty and Healthy Aging (CIBERFES), Madrid, Spain
| | - Robert Csapo
- Research Unit for Orthopaedic Sports Medicine and Injury Prevention, ISAG, University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria
| | - Luis M Alegre
- GENUD Toledo Research Group, Universidad de Castilla-La Mancha, Toledo, Spain.,CIBER of Frailty and Healthy Aging (CIBERFES), Madrid, Spain
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21
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Muscle Performance Changes with Age in Active Women. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18094477. [PMID: 33922474 PMCID: PMC8122865 DOI: 10.3390/ijerph18094477] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 04/12/2021] [Accepted: 04/20/2021] [Indexed: 01/16/2023]
Abstract
The purpose of this study was to examine age-related differences in muscle performance in women divided into young (YW, 20–39 years, n = 29) middle-aged (MAW, 40–59 years, n = 33), and older (OW, ≥60 years, n = 40) age groups. Methods: Hand grip strength, vertical jump performance, and knee extensor (KE) strength (0 deg/s, 60 deg/s, and 240 deg/s), speed of movement (SoM; at 1 Nm, 20%, 40%, and 60% isometric strength), and endurance (30-repetition test at 60 degs/s and 240 deg/s) were assessed. Computed tomography-acquired muscle cross-sectional area (mCSA) was measured and included to determine specific strength (KE strength/mCSA). Results: Hand grip strength was similar across groups, while jump performance declined with age (YW and MAW > OW, p < 0.001). KE strength declined significantly with age (all conditions p < 0.01), while specific strength was similar across groups. SoM was significantly higher for YW and MAW compared to OW (both p < 0.01). An age × velocity interaction revealed YW KE endurance was similar between conditions, whereas MAW and OW displayed significantly better endurance during the 60 deg/s condition. OW displayed impaired KE endurance at 240 deg/s (vs. YW and MAW, p < 0.01) but improved at 60 deg/s (vs. YW, p < 0.01). Dynamic torque decline increased with age (YW < OW, p = 0.03) and was associated with intramuscular adipose tissue (r = 0.21, p = 0.04). Conclusions: Performance declines were most evident among OW, but few performance deficits had emerged in MAW. Interestingly, strength declines disappeared after normalizing to mCSA and endurance appears to be velocity-dependent.
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22
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Fitzgerald LF, Ryan MM, Bartlett MF, Miehm JD, Kent JA. Muscle architecture, voluntary activation, and low-frequency fatigue do not explain the greater fatigue of older compared with young women during high-velocity contractions. PLoS One 2020; 15:e0234217. [PMID: 33141870 PMCID: PMC7608879 DOI: 10.1371/journal.pone.0234217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 10/18/2020] [Indexed: 11/18/2022] Open
Abstract
Although high-velocity contractions elicit greater muscle fatigue in older than young adults, the cause of this difference is unclear. We examined the potential roles of resting muscle architecture and baseline contractile properties, as well as changes in voluntary activation and low-frequency fatigue in response to high-velocity knee extensor work. Vastus lateralis muscle architecture was determined in quiescent muscle by ultrasonography in 8 young (23.4±1.8 yrs) and 8 older women (69.6±1.1). Maximal voluntary dynamic (MVDC) and isometric (MVIC), and stimulated (80Hz and 10Hz, 500ms) isometric contractions were performed before and immediately after 120 MVDCs (240°.s-1, one every 2s). Architecture variables did not differ between groups (p≥0.209), but the half-time of torque relaxation (T1/2) was longer in older than young women at baseline (151.9±6.0 vs. 118.8±4.4 ms, respectively, p = 0.001). Older women fatigued more than young (to 33.6±4.7% vs. 55.2±4.2% initial torque, respectively; p = 0.004), with no evidence of voluntary activation failure (ΔMVIC:80Hz torque) in either group (p≥0.317). Low-frequency fatigue (Δ10:80Hz torque) occurred in both groups (p<0.001), as did slowing of T1/2 (p = 0.001), with no differences between groups. Baseline T1/2 was inversely associated with fatigue in older (r2 = 0.584, p = 0.045), but not young women (r2 = 0.147, p = 0.348). These results indicate that differences in muscle architecture, voluntary activation, and low-frequency fatigue do not explain the greater fatigue of older compared with young women during high-velocity contractions. The inverse association between baseline T1/2 and fatigue in older women suggests that factors related to slower muscle contractile properties may be protective against fatigue during fast, repetitive contractions in aging.
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Affiliation(s)
- Liam F. Fitzgerald
- Department of Kinesiology, University of Massachusetts Amherst, Amherst, Massachusetts, United States of America
- * E-mail:
| | - Margaret M. Ryan
- Department of Kinesiology, University of Massachusetts Amherst, Amherst, Massachusetts, United States of America
| | - Miles F. Bartlett
- Department of Kinesiology, University of Massachusetts Amherst, Amherst, Massachusetts, United States of America
| | - Jules D. Miehm
- Department of Kinesiology, University of Massachusetts Amherst, Amherst, Massachusetts, United States of America
| | - Jane A. Kent
- Department of Kinesiology, University of Massachusetts Amherst, Amherst, Massachusetts, United States of America
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Wu R, Ditroilo M, Delahunt E, De Vito G. Age Related Changes in Motor Function (II). Decline in Motor Performance Outcomes. Int J Sports Med 2020; 42:215-226. [PMID: 33137831 DOI: 10.1055/a-1265-7073] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Age-related impairments in motor performance are caused by a deterioration in mechanical and neuromuscular functions, which have been investigated from the macro-level of muscle-tendon unit to the micro-level of the single muscle fiber. When compared to the healthy young skeletal muscle, aged skeletal muscle is: (1) weaker, slower and less powerful during the performance of voluntary contractions; (2) less steady during the performance of isometric contractions, particularly at low levels of force; and (3) less susceptible to fatigue during the performance of sustained isometric contractions, but more susceptible to fatigue during the performance of high-velocity dynamic contractions. These impairments have been discussed to be mainly the result of: a) loss of muscle mass and selective atrophy of type II muscle fibers; b) altered tendon mechanical properties (decreased tendon stiffness); c) reduced number and altered function of motor units; d) slower muscle fiber shortening velocity; e) increased oscillation in common synaptic input to motor neurons; and f) altered properties and activity of sarcoplasmic reticulum. In this second part of a two-part review we have detailed the age-related impairments in motor performance with a reference to the most important mechanical and neuromuscular contributing factors.
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Affiliation(s)
- Rui Wu
- School of Public Health Physiotherapy and Sports Science, University College Dublin, Dublin
| | - Massimiliano Ditroilo
- School of Public Health Physiotherapy and Sports Science, University College Dublin, Dublin
| | - Eamonn Delahunt
- School of Public Health Physiotherapy and Sports Science, University College Dublin, Dublin
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24
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Yacyshyn AF, McNeil CJ. Electrically evoked force loss of the knee extensors is equivalent for young and old females and males. Appl Physiol Nutr Metab 2020; 45:1270-1276. [DOI: 10.1139/apnm-2020-0199] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Data are scant on sex-related differences for electrically evoked contractions, which assess intrinsic contractile properties while limiting spinal and supraspinal adaptations to mitigate fatigue. Furthermore, the few studies that exist use stimulus frequencies considerably higher than the natural motor unit discharge rate for the target force. The purpose of this study was to compare force loss to electrically evoked contractions at a physiological stimulus frequency among young females (n = 12), young males (n = 12), old females (n = 11), and old males (n = 11). The quadriceps of the dominant leg were fatigued by 3 min of intermittent transcutaneous muscle belly stimulation (15 Hz stimulus train to initially evoke 25% of maximal voluntary force). Impairment of tetanic contractile impulse (area under the curve) did not differ between sexes for young or old adults or between age groups, with a pooled value of 55.2% ± 12.4% control at the end of fatigue. These data contrast with previous findings at 30 Hz, when the quadriceps of females had greater fatigue resistance than males for young and old adults. The present results highlight the impact stimulus frequency has on intrinsic fatigability of muscle; the findings have implications for future fatigue paradigms and treatment approaches when utilizing electrical stimulation for rehabilitation. Novelty Fatigue was not different between sexes with a stimulation frequency comparable to discharge rates during voluntary contractions. These results highlight that stimulus frequency not only influences fatigue development but also between-group differences.
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Affiliation(s)
- Alexandra F. Yacyshyn
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, The University of British Columbia – Okanagan Campus, 1147 Research Road, Kelowna, BC V1V 1V7, Canada
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, The University of British Columbia – Okanagan Campus, 1147 Research Road, Kelowna, BC V1V 1V7, Canada
| | - Chris J. McNeil
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, The University of British Columbia – Okanagan Campus, 1147 Research Road, Kelowna, BC V1V 1V7, Canada
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, The University of British Columbia – Okanagan Campus, 1147 Research Road, Kelowna, BC V1V 1V7, Canada
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25
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Otieno LA, Semmler JG, Sidhu SK. Single joint fatiguing exercise decreases long but not short-interval intracortical inhibition in older adults. Exp Brain Res 2020; 239:47-58. [PMID: 33098654 DOI: 10.1007/s00221-020-05958-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 10/13/2020] [Indexed: 12/18/2022]
Abstract
Ageing is accompanied by neuromuscular changes which may alter fatigue in older adults. These changes may include changes in corticospinal excitatory and inhibitory processes. Previous research has suggested that single joint fatiguing exercise decreases short-(SICI) and long-(LICI) interval intracortical inhibition in young adults. However, this is yet to be established in older adults. In 19 young (23 ± 4 years) and 18 older (69 ± 5 years) adults, SICI (2 ms interstimulus interval; ISI) and LICI (100 ms ISI) were measured in a resting first dorsal interosseous (FDI) muscle using transcranial magnetic stimulation (TMS) before and after a 15 min sustained submaximal contraction at 25% of their maximum EMG. Subsequent ten 2-min contractions held at 25% EMG were also performed to sustain fatigue for a total of 30 min, while SICI and LICI were taken immediately after each contraction. There was no change in SICI post-fatiguing exercise compared to baseline in both young and older adults (P = 0.4). Although there was no change in LICI post-fatiguing exercise in younger adults (P = 1.0), LICI was attenuated in older adults immediately post-fatiguing exercise and remained attenuated post-fatigue (PF)1 and PF2 (P < 0.05). Contrary to previous studies, the lack of change in SICI and LICI in young adults following a sustained submaximal EMG contraction suggests that GABA modulation may be dependent on the type of fatiguing task performed. The reduction in LICI in older adults post-fatiguing exercise suggests an age-related decrease in GABAB-mediated activity with sustained submaximal fatiguing exercise.
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Affiliation(s)
- Lavender A Otieno
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, S433, Helen Mayo South, Frome Rd, Adelaide, South Australia, 5005, Australia
| | - John G Semmler
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, S433, Helen Mayo South, Frome Rd, Adelaide, South Australia, 5005, Australia
| | - Simranjit K Sidhu
- Discipline of Physiology, Adelaide Medical School, The University of Adelaide, S433, Helen Mayo South, Frome Rd, Adelaide, South Australia, 5005, Australia.
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26
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Reimann H, Ramadan R, Fettrow T, Hafer JF, Geyer H, Jeka JJ. Interactions Between Different Age-Related Factors Affecting Balance Control in Walking. Front Sports Act Living 2020; 2:94. [PMID: 33345085 PMCID: PMC7739654 DOI: 10.3389/fspor.2020.00094] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Accepted: 07/12/2020] [Indexed: 12/30/2022] Open
Abstract
Maintaining balance during walking is a continuous sensorimotor control problem. Throughout the movement, the central nervous system has to collect sensory data about the current state of the body in space, use this information to detect possible threats to balance and adapt the movement pattern to ensure stability. Failure of this sensorimotor loop can lead to dire consequences in the form of falls, injury and death. Such failures tend to become more prevalent as people get older. While research has established a number of factors associated with higher risk of falls, we know relatively little about age-related changes of the underlying sensorimotor control loop and how such changes are related to empirically established risk factors. This paper approaches the problem of age-related fall risk from a neural control perspective. We begin by summarizing recent empirical findings about the neural control laws mapping sensory input to motor output for balance control during walking. These findings were established in young, neurotypical study populations and establish a baseline of sensorimotor control of balance. We then review correlates for deteriorating balance control in older adults, of muscle weakness, slow walking, cognitive decline, and increased visual dependency. While empirical associations between these factors and fall risk have been established reasonably well, we know relatively little about the underlying causal relationships. Establishing such causal relationships is hard, because the different factors all co-vary with age and are difficult to isolate empirically. One option to analyze the role of an individual factor for balance control is to use computational models of walking comprising all levels of the sensorimotor control loop. We introduce one such model that generates walking movement patterns from a short list of spinal reflex modules with limited supraspinal modulation for balance. We show how this model can be used to simulate empirical studies, and how comparison between the model and empirical results can indicate gaps in our current understanding of balance control. We also show how different aspects of aging can be added to this model to study their effect on balance control in isolation.
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Affiliation(s)
- Hendrik Reimann
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, United States
| | - Rachid Ramadan
- Institute for Neural Computation, Ruhr University, Bochum, Germany
| | - Tyler Fettrow
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, United States
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, FL, United States
| | - Jocelyn F. Hafer
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, United States
| | - Hartmut Geyer
- Robotics Institute, Carnegie Mellon University, Pittsburgh, PA, United States
| | - John J. Jeka
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE, United States
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Muscle fatigability measured with Pneumatic and Hydraulic handgrip systems are not interchangeable. Exp Gerontol 2020; 136:110950. [PMID: 32315730 DOI: 10.1016/j.exger.2020.110950] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 04/06/2020] [Accepted: 04/11/2020] [Indexed: 11/20/2022]
Abstract
BACKGROUND Fatigue resistance (FR) was here defined as the time during which grip strength (GS) drops to 50% of its maximum during sustained contraction. Since different GS systems exist, we compared FR obtained with Pneumatic (Pneu) and Hydraulic (Hydr) handgrip systems. Hand pain induced by both systems was also investigated since this might influence FR-outcomes. METHODS 618 young controls (Y: reference group), 426 middle-aged (MA) and 234 old community-dwelling adults (OLD), and 50 hospitalized patients (HOSP) participated. FR was recorded with Pneu and Hydr. Grip work corrected for body weight (area under the strength-time curve; GWBW = 0.75 ∗ maximal GS ∗ FR / body weight) was calculated. We corrected for body weight since heavier or more obese participants will have to engage more strength and sustain the effort over time. Thereafter GWBW was expressed as T-scores representing the deviation from the mean score of the sex-specific reference group. Experienced pain, its intensity and whether pain hindered participants to sustain the contraction were questioned. RESULTS Overall, although significant correlation between FR measured with both systems was found (r = 0.418, p < 0.001), FR measured by Pneu (55.7 ± 35.0 s) was higher compared to Hydr (34.2 ± 18.4 s). There was a proportional difference in FR measured with both systems (R2 = 0.36, p < 0.001), highlighting the longer participants could sustain FR test, the higher the difference in FR measured with both systems. Overall, there was no difference in pain variables between both systems. Independent of sex and system, GWBW deviated less from reference group in MA compared to OLD and HOSP. In OLD, GWBW deviated less from reference group than HOSP, independent of sex and system. CONCLUSION Participants were unable to sustain the contraction with Hydr as long as with Pneu. Hydr seems less able to identify subjects with higher levels of muscle endurance. Based on the GWBM-scores we can conclude that either system can be used for assessing muscle fatigability, but Pneu may be more sensitive as differences can be detected more easily.
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28
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Regular endurance exercise of overloaded muscle of young and old male mice does not attenuate hypertrophy and improves fatigue resistance. GeroScience 2020; 43:741-757. [PMID: 32643063 PMCID: PMC8110681 DOI: 10.1007/s11357-020-00224-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 06/26/2020] [Indexed: 12/16/2022] Open
Abstract
It has been observed that there is an inverse relationship between fiber size and oxidative capacity due to oxygen, ADP, and ATP diffusion limitations. We aimed to see if regular endurance exercise alongside a hypertrophic stimulus would lead to compromised adaptations to both, particularly in older animals. Here we investigated the effects of combining overload with regular endurance exercise in young (12 months) and old (26 months) male mice. The plantaris muscles of these mice were overloaded through denervation of synergists to induce hypertrophy and the mice ran on a treadmill for 30 min per day for 6 weeks. The hypertrophic response to overload was not blunted by endurance exercise, and the increase in fatigue resistance with endurance exercise was not reduced by overload. Old mice demonstrated less hypertrophy than young mice, which was associated with impaired angiogenesis and a reduction in specific tension. The data of this study suggest that combining endurance exercise and overload induces the benefits of both types of exercise without compromising adaptations to either. Additionally, the attenuated hypertrophic response to overload in old animals may be due to a diminished capacity for capillary growth.
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29
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Hafer JF, Boyer KA. Comparisons of Knee Extensor Functional Demand During Gait by Age, Physical Activity Level, and the Impact of Acute Exercise and Walking Speed. J Appl Biomech 2020; 36:163-170. [PMID: 32335528 DOI: 10.1123/jab.2019-0361] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 01/22/2020] [Accepted: 02/19/2020] [Indexed: 11/18/2022]
Abstract
The link between age-related changes in muscle strength and gait is unclear. We tested if knee extensor functional demand differs by age and physical activity status and if functional demand increases with walking speed or after exercise. Gait and knee extensor muscle torque were collected from young adults and highly and less active older adults before and after treadmill walking. Functional demand was the ratio of knee moments during gait to knee extensor muscle torques estimated from participant-specific torque-velocity curves. Functional demand at the peak knee flexion moment was greater in less active older adults than young adults (29.3% [14.3%] vs 24.6% [12.1%]) and increased with walking speed (32.0% [13.9%] vs 22.8% [10.4%]). Functional demand at both knee extension moments increased ∼2% to 3% after exercise. The low functional demand found in this study suggests that healthy adults maintain a reserve of knee extensor strength.
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Affiliation(s)
- Jocelyn F Hafer
- University of Delaware
- University of Michigan
- University of Massachusetts Amherst
| | - Katherine A Boyer
- University of Massachusetts Amherst
- University of Massachusetts Medical School
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30
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Age-related neuromuscular fatigue and recovery after cycling: Measurements in isometric and dynamic modes. Exp Gerontol 2020; 133:110877. [DOI: 10.1016/j.exger.2020.110877] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 02/08/2020] [Accepted: 02/10/2020] [Indexed: 01/02/2023]
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31
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Teigen LE, Sundberg CW, Kelly LJ, Hunter SK, Fitts RH. Ca 2+ dependency of limb muscle fiber contractile mechanics in young and older adults. Am J Physiol Cell Physiol 2020; 318:C1238-C1251. [PMID: 32348175 DOI: 10.1152/ajpcell.00575.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Age-induced declines in skeletal muscle contractile function have been attributed to multiple cellular factors, including lower peak force (Po), decreased Ca2+ sensitivity, and reduced shortening velocity (Vo). However, changes in these cellular properties with aging remain unresolved, especially in older women, and the effect of submaximal Ca2+ on contractile function is unknown. Thus, we compared contractile properties of muscle fibers from 19 young (24 ± 3 yr; 8 women) and 21 older adults (77 ± 7 yr; 7 women) under maximal and submaximal Ca2+ and assessed the abundance of three proteins thought to influence Ca2+ sensitivity. Fast fiber cross-sectional area was ~44% larger in young (6,479 ± 2,487 µm2) compared with older adults (4,503 ± 2,071 µm2, P < 0.001), which corresponded with a greater absolute Po (young = 1.12 ± 0.43 mN; old = 0.79 ± 0.33 mN, P < 0.001). There were no differences in fast fiber size-specific Po, indicating the age-related decline in force was explained by differences in fiber size. Except for fast fiber size and absolute Po, no age or sex differences were observed in Ca2+ sensitivity, rate of force development (ktr), or Vo in either slow or fast fibers. Submaximal Ca2+ depressed ktr and Vo, but the effects were not altered by age in either sex. Contrary to rodent studies, regulatory light chain (RLC) and myosin binding protein-C abundance and RLC phosphorylation were unaltered by age or sex. These data suggest the age-associated reductions in contractile function are primarily due to the atrophy of fast fibers and that caution is warranted when extending results from rodent studies to humans.
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Affiliation(s)
- Laura E Teigen
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin
| | - Christopher W Sundberg
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin.,Department of Physical Therapy, Marquette University, Milwaukee, Wisconsin
| | - Lauren J Kelly
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin
| | - Sandra K Hunter
- Department of Physical Therapy, Marquette University, Milwaukee, Wisconsin
| | - Robert H Fitts
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin
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32
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Bartlett MF, Fitzgerald LF, Nagarajan R, Hiroi Y, Kent JA. Oxidative ATP synthesis in human quadriceps declines during 4 minutes of maximal contractions. J Physiol 2020; 598:1847-1863. [PMID: 32045011 DOI: 10.1113/jp279339] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 01/30/2020] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS During maximal exercise, skeletal muscle metabolism and oxygen consumption remain elevated despite precipitous declines in power. Presently, it is unclear whether these responses are caused by an increased ATP cost of force generation (ATPCOST ) or mitochondrial uncoupling; a process that reduces the efficiency of oxidative ATP synthesis (ATPOX ). To address this gap, we used 31-phosphorus magnetic resonance spectroscopy to measure changes in ATPCOST and ATPOX in human quadriceps during repeated trials of maximal intensity knee extensions lasting up to 4 min. ATPCOST remained unchanged. In contrast, ATPOX plateaued by ∼2 min and then declined (∼15%) over the final 2 min. The maximal capacity for ATPOX (Vmax ), as well as ADP-specific rates of ATPOX , were also significantly diminished. Collectively, these results suggest that mitochondrial uncoupling, and not increased ATPCOST , is responsible for altering the regulation of skeletal muscle metabolism and oxygen consumption during maximal exercise. ABSTRACT The relationship between skeletal muscle oxygen consumption and power output is augmented during exercise at workloads above the lactate threshold. Potential mechanisms for this response have been hypothesized, including increased ATP cost of force generation (ATPCOST ) and mitochondrial uncoupling, a process that reduces the efficiency of oxidative ATP synthesis (ATPOX ). To test these hypotheses, we used phosphorus magnetic resonance spectroscopy to non-invasively measure changes in phosphate concentrations and pH in the vastus lateralis muscle of nine young adults during repeated trials of maximal, all-out dynamic knee extensions (120°s-1 , 1 every 2 s) lasting 24, 60, 120, and 240 s. ATPOX was measured at each time point from the initial velocity of PCr resynthesis, and ATPCOST was calculated as the sum of ATP synthesized by the creatine and adenylate kinase reactions, non-oxidative glycolysis, ATPOX and net changes in [ATP]. Power output declined in a reproducible manner for all four trials. ATPCOST did not change over time (main effect P = 0.45). ATPOX plateaued from 60 to 120 s and then decreased over the final 120 s (main effect P = 0.001). The maximal capacity for oxidative ATP synthesis (Vmax ), as well as ADP-specific rates of ATPOX , also decreased over time (main effect P = 0.001, both). Collectively, these results demonstrate that prolonged maximal contraction protocols impair oxidative energetics and implicate mitochondrial uncoupling as the mechanism for this response. The causes of mitochondrial uncoupling are presently unknown but may offer a potential explanation for the dissociation between skeletal muscle power output and oxygen consumption during maximal, all-out exercise protocols.
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Affiliation(s)
- Miles F Bartlett
- Muscle Physiology Laboratory, Department of Kinesiology, University of Massachusetts, Amherst, Massachusetts, 01003.,Department of Kinesiology, University of Texas, Arlington, Texas, 76019
| | - Liam F Fitzgerald
- Muscle Physiology Laboratory, Department of Kinesiology, University of Massachusetts, Amherst, Massachusetts, 01003
| | - Rajakumar Nagarajan
- Human Magnetic Resonance Center, Institute for Applied Life Sciences (IALS), University of Massachusetts, Amherst, Massachusetts, 01003
| | - Yeun Hiroi
- Muscle Physiology Laboratory, Department of Kinesiology, University of Massachusetts, Amherst, Massachusetts, 01003
| | - Jane A Kent
- Muscle Physiology Laboratory, Department of Kinesiology, University of Massachusetts, Amherst, Massachusetts, 01003
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Borzuola R, Giombini A, Torre G, Campi S, Albo E, Bravi M, Borrione P, Fossati C, Macaluso A. Central and Peripheral Neuromuscular Adaptations to Ageing. J Clin Med 2020; 9:jcm9030741. [PMID: 32182904 PMCID: PMC7141192 DOI: 10.3390/jcm9030741] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 02/27/2020] [Accepted: 03/04/2020] [Indexed: 12/31/2022] Open
Abstract
Ageing is accompanied by a severe muscle function decline presumably caused by structural and functional adaptations at the central and peripheral level. Although researchers have reported an extensive analysis of the alterations involving muscle intrinsic properties, only a limited number of studies have recognised the importance of the central nervous system, and its reorganisation, on neuromuscular decline. Neural changes, such as degeneration of the human cortex and function of spinal circuitry, as well as the remodelling of the neuromuscular junction and motor units, appear to play a fundamental role in muscle quality decay and culminate with considerable impairments in voluntary activation and motor performance. Modern diagnostic techniques have provided indisputable evidence of a structural and morphological rearrangement of the central nervous system during ageing. Nevertheless, there is no clear insight on how such structural reorganisation contributes to the age-related functional decline and whether it is a result of a neural malfunction or serves as a compensatory mechanism to preserve motor control and performance in the elderly population. Combining leading-edge techniques such as high-density surface electromyography (EMG) and improved diagnostic procedures such as functional magnetic resonance imaging (fMRI) or high-resolution electroencephalography (EEG) could be essential to address the unresolved controversies and achieve an extensive understanding of the relationship between neural adaptations and muscle decline.
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Affiliation(s)
- Riccardo Borzuola
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, 00135 Rome, Italy; (R.B.); (A.G.); (P.B.); (C.F.); (A.M.)
| | - Arrigo Giombini
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, 00135 Rome, Italy; (R.B.); (A.G.); (P.B.); (C.F.); (A.M.)
| | - Guglielmo Torre
- Department of Orthopaedic And Trauma Surgery, Campus Bio-Medico University of Rome, 00128 Rome, Italy; (S.C.); (E.A.)
- Correspondence: ; Tel.: +6-225-418-825
| | - Stefano Campi
- Department of Orthopaedic And Trauma Surgery, Campus Bio-Medico University of Rome, 00128 Rome, Italy; (S.C.); (E.A.)
| | - Erika Albo
- Department of Orthopaedic And Trauma Surgery, Campus Bio-Medico University of Rome, 00128 Rome, Italy; (S.C.); (E.A.)
| | - Marco Bravi
- Department of Physical Medicine and Rehabilitation, Campus Bio-Medico University of Rome, 00128 Rome, Italy;
| | - Paolo Borrione
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, 00135 Rome, Italy; (R.B.); (A.G.); (P.B.); (C.F.); (A.M.)
| | - Chiara Fossati
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, 00135 Rome, Italy; (R.B.); (A.G.); (P.B.); (C.F.); (A.M.)
| | - Andrea Macaluso
- Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, 00135 Rome, Italy; (R.B.); (A.G.); (P.B.); (C.F.); (A.M.)
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34
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Older Adults Differentially Modulate Transcranial Magnetic Stimulation-Electroencephalography Measures of Cortical Inhibition during Maximal Single-joint Exercise. Neuroscience 2019; 425:181-193. [PMID: 31809730 DOI: 10.1016/j.neuroscience.2019.11.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 11/11/2019] [Accepted: 11/12/2019] [Indexed: 12/22/2022]
Abstract
The effects of muscle fatigue are known to be altered in older adults, and age-related changes in the brain are likely to be a contributing factor. However, the neural mechanisms underlying these changes are not known. The aim of the current study was to use transcranial magnetic stimulation combined with electroencephalography (TMS-EEG) to investigate age-related changes in cortical excitability with muscle fatigue. In 23 young (mean age ± SD: 22 ± 2 years) and 17 older (mean age ± SD: 68.3 ± 5.6 years) adults, single-pulse TMS-EEG was applied before, during and after the performance of fatiguing, intermittent isometric abduction of the index finger. Motor-evoked potential (MEP) measures of cortical excitability were increased during (estimated mean difference, 123.3%; P < 0.0001) and after (estimated mean difference, 117.5%; P = 0.001) fatigue and this was not different between groups (P > 0.5). For TMS-EEG, the amplitude of the P30 and P180 potentials were unaffected by fatigue in older participants (P > 0.05). In contrast, the amplitude of the N45 potential in older adults was significantly reduced both during (positive cluster: mean voltage difference = 0.7 µV, P < 0.005; negative cluster: mean voltage difference = 0.9 µV, P < 0.0005) and after (mean voltage difference = 0.5 µV, P < 0.005) fatiguing exercise, whereas this response was absent in young participants. These results suggest that performance of maximal intermittent isometric exercise in old but not young adults is associated with modulation of cortical inhibition likely mediated by activation of gamma-aminobutyric acid type A receptors.
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Morphological alterations of mouse skeletal muscles during early ageing are muscle specific. Exp Gerontol 2019; 125:110684. [DOI: 10.1016/j.exger.2019.110684] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 07/12/2019] [Accepted: 08/05/2019] [Indexed: 12/14/2022]
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Mateus A, Rebelo J, Silva AG. Effects of a Multimodal Exercise Program Plus Neural Gliding on Postural Control, Pain, and Flexibility of Institutionalized Older Adults: A Randomized, Parallel, and Double-Blind Study. J Geriatr Phys Ther 2019; 43:3-11. [PMID: 31569173 DOI: 10.1519/jpt.0000000000000249] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND AND PURPOSE The effect of adding neural mobilization to a multimodal program of exercises has not been investigated, despite its potential positive effects. The aim of this study was to compare the acute effects of a multimodal exercise program and neural gliding against a multimodal exercise program only, on pain intensity, gait speed, Timed Up and Go (TUG) test, lower limb flexibility, and static balance of institutionalized older adults. METHODS Older adults who were institutionalized (n = 26) were randomized to receive a multimodal exercise program plus neural gliding or a multimodal exercise program only. Both interventions were delivered twice a week for 8 weeks. Participants were assessed for pain, gait velocity, balance, flexibility, and TUG at baseline and postintervention. RESULTS A significant main effect of time for pain intensity (F1,24 = 8.95, P = .006), balance (F1,24 = 10.29, P = .004), and gait velocity (F1,24 = 5.51, P = .028) was observed, indicating a positive impact of both interventions. No other significant effects were found (TUG and flexibility; P > .05). DISCUSSION A 45-minute multimodal exercise program, twice a week for 8 weeks, has a positive impact on pain intensity, balance, and gait velocity, but neural gliding has no additional benefit. It is unclear whether dose and type of neural mobilization may have had an impact on results. Considering the structural and physiological changes that tend to occur with age, future studies could explore the effects of neural tensioning or of higher doses of neural mobilization. CONCLUSIONS This study suggests that adding neural gliding to a multimodal exercise program has no additional benefit.
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Affiliation(s)
- Ana Mateus
- School of Health Sciences, University of Aveiro, Campus Universitário de Santiago, Portugal
| | - Jessica Rebelo
- Lar Santa Catarina do Reboleiro, Avenida da Ribeirinha, Trancoso, Portugal
| | - Anabela G Silva
- School of Health Sciences, University of Aveiro, Campus Universitário de Santiago, Portugal.,CINTESIS.UA, University of Aveiro, Campus Universitário de Santiago, Portugal
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Abstract
Older females experience higher rates of disability than males, potentially due to sex-specific differences in gait and muscle function. The authors evaluated the effects of age and physical activity (PA) on gait mechanics and knee extensor muscle function in males and females. Three groups of 20 individuals (each 10 females) participated: young (21-35 y) and highly and less active older (55-70 y) adults. Knee extensor strength and joint mechanics during preferred speed gait were collected before and after 30 minutes of walking. Age by sex and PA by sex interactions indicated older and less active older females had lower concentric knee extensor muscle power and larger hip extension moments than males. After 30 minutes of walking, older less active adults had larger decreases in knee extensor power than their highly active older counterparts, and older adults of both sexes had decreases in ankle dorsiflexion moments while young adults did not. These results suggest that older, particularly less active, adults are susceptible to knee extensor muscle fatigue from moderate activity. For older adults, high levels of PA may be necessary to preserve gait mechanics in response to a bout of exercise. This new information may be important for targeting interventions in at-risk older adults.
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Iglesias-Soler E, Mayo X, Rial-Vázquez J, Morín-Jiménez A, Aracama A, Guerrero-Moreno JM, Jaric S. Reliability of force-velocity parameters obtained from linear and curvilinear regressions for the bench press and squat exercises. J Sports Sci 2019; 37:2596-2603. [PMID: 31354059 DOI: 10.1080/02640414.2019.1648993] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
This study aimed to compare the goodness of fit and the reliability of different regression models for fitting the force-velocity relationship (FV) of bench press (BP) and squat (SQ). Additionally, the reliability of the position on FV of the velocity (V1RM) and the force performed with the 1RM (F1RM) was explored. Nine rugby players and 12 judokas participated in this study. The FV of BP and SQ were obtained twice by a protocol performed until the 1RM. Individual FV were fitted by linear (LM), quadratic polynomial (PM), and exponential models (EM). Adjusted coefficients of determination of LM and PM (medians higher than 0.919) were higher than for EM. The reliability was higher for LM in comparison with PM. The reliability of V1RM was not acceptable (CV% = 19 and 18% for BP and SQ). High reliability was observed for F1RM (CV% = 3 and 2% for BP and SQ) and for the ratio between F1RM and the force-axis intercept of FV (CV% = 2 and 4% for BP and SQ). The reliability of the relative values of F1RM around 92 and 87% of F0 for BP and SQ suggests the use of these values for monitoring resistance training programmes.
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Affiliation(s)
- Eliseo Iglesias-Soler
- Performance and Health Group, Department of Physical Education and Sport, Faculty of Sports Sciences and Physical Education, University of A Coruna , A Coruña , Spain
| | - Xian Mayo
- Performance and Health Group, Department of Physical Education and Sport, Faculty of Sports Sciences and Physical Education, University of A Coruna , A Coruña , Spain.,Active and Healthy Lifestyle Observatory, Centre for Sport Studies, King Juan Carlos University , Madrid , Spain
| | - Jessica Rial-Vázquez
- Performance and Health Group, Department of Physical Education and Sport, Faculty of Sports Sciences and Physical Education, University of A Coruna , A Coruña , Spain
| | - Antonio Morín-Jiménez
- Performance and Health Group, Department of Physical Education and Sport, Faculty of Sports Sciences and Physical Education, University of A Coruna , A Coruña , Spain
| | - Asier Aracama
- Performance and Health Group, Department of Physical Education and Sport, Faculty of Sports Sciences and Physical Education, University of A Coruna , A Coruña , Spain
| | - Jose María Guerrero-Moreno
- Performance and Health Group, Department of Physical Education and Sport, Faculty of Sports Sciences and Physical Education, University of A Coruna , A Coruña , Spain
| | - Slobodan Jaric
- Department of Kinesiology and Applied Physiology & Biomechanics and Movement Science Graduate Program, University of Delaware , Newark , NJ , USA
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Wu R, Delahunt E, Ditroilo M, Ferri Marini C, De Vito G. Torque steadiness and neuromuscular responses following fatiguing concentric exercise of the knee extensor and flexor muscles in young and older individuals. Exp Gerontol 2019; 124:110636. [PMID: 31195103 DOI: 10.1016/j.exger.2019.110636] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 05/16/2019] [Accepted: 06/09/2019] [Indexed: 11/17/2022]
Abstract
The purpose of this study was to investigate the age-related alterations in the ability to exert maximal and to sustain submaximal isometric muscle torques after a fatiguing concentric exercise conducted with knee extensor (KE) and flexor (KF) muscles. Sixteen young (aged 19-30 years; 8 women) and 17 older (aged 65-75 years; 9 women) volunteers participated. The following tasks were performed before and immediately after 22 maximal concentric efforts of the right KE and KF at 1.05 rad/s: (1) a maximal voluntary isometric contraction (MVIC) task involving both KE and KF; and (2) a KE torque-steadiness task at a submaximal target contraction intensity (20% MVIC). During the dynamometric tests, surface EMG was recorded simultaneously from the KE and KF muscles. Fatigue-induced reductions in knee extension MVIC were similar (~15%) between groups, but young participants showed more pronounced declines in agonist (i.e. quadriceps) EMG responses in both time (RMS amplitude; ~15% vs. ~10%, p < 0.001) and frequency (median frequency; ~14% vs. ~8%, p < 0.01) domains. Torque steadiness exhibited a similar post-fatigue decrease in the two age groups (p < 0.01), but interestingly agonist activation (~17%; p < 0.001) and antagonist (i.e. hamstrings) co-activation (~16%; p < 0.001) declined only in the older participants. These findings suggest that the fatiguing concentric KE and KF exercise results in similar relative reductions (%) in maximal torque and steadiness of the KE in young and older individuals, but they are sustained by different age-related neuromuscular strategies.
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Affiliation(s)
- Rui Wu
- School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland.
| | - Eamonn Delahunt
- School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland; Institute for Sport and Health, University College Dublin, Dublin, Ireland
| | - Massimiliano Ditroilo
- School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland; Institute for Sport and Health, University College Dublin, Dublin, Ireland
| | - Carlo Ferri Marini
- Department of Biomolecular Science, University of Urbino Carlo Bo, Italy
| | - Giuseppe De Vito
- School of Public Health, Physiotherapy and Sports Science, University College Dublin, Dublin, Ireland; Institute for Sport and Health, University College Dublin, Dublin, Ireland
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Sundberg CW, Prost RW, Fitts RH, Hunter SK. Bioenergetic basis for the increased fatigability with ageing. J Physiol 2019; 597:4943-4957. [PMID: 31018011 DOI: 10.1113/jp277803] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 04/18/2019] [Indexed: 12/25/2022] Open
Abstract
KEY POINTS The mechanisms for the age-related increase in fatigability during dynamic exercise remain elusive. We tested whether age-related impairments in muscle oxidative capacity would result in a greater accumulation of fatigue causing metabolites, inorganic phosphate (Pi ), hydrogen (H+ ) and diprotonated phosphate (H2 PO4 - ), in the muscle of old compared to young adults during a dynamic knee extension exercise. The age-related increase in fatigability (reduction in mechanical power) of the knee extensors was closely associated with a greater accumulation of metabolites within the working muscle but could not be explained by age-related differences in muscle oxidative capacity. These data suggest that the increased fatigability in old adults during dynamic exercise is primarily determined by age-related impairments in skeletal muscle bioenergetics that result in a greater accumulation of metabolites. ABSTRACT The present study aimed to determine whether the increased fatigability in old adults during dynamic exercise is associated with age-related differences in skeletal muscle bioenergetics. Phosphorus nuclear magnetic resonance spectroscopy was used to quantify concentrations of high-energy phosphates and pH in the knee extensors of seven young (22.7 ± 1.2 years; six women) and eight old adults (76.4 ± 6.0 years; seven women). Muscle oxidative capacity was measured from the phosphocreatine (PCr) recovery kinetics following a 24 s maximal voluntary isometric contraction. The fatiguing exercise consisted of 120 maximal velocity contractions (one contraction per 2 s) against a load equivalent to 20% of the maximal voluntary isometric contraction. The PCr recovery kinetics did not differ between young and old adults (0.023 ± 0.007 s-1 vs. 0.019 ± 0.004 s-1 , respectively). Fatigability (reductions in mechanical power) of the knee extensors was ∼1.8-fold greater with age and was accompanied by a greater decrease in pH (young = 6.73 ± 0.09, old = 6.61 ± 0.04) and increases in concentrations of inorganic phosphate, [Pi ], (young = 22.7 ± 4.8 mm, old = 32.3 ± 3.6 mm) and diprotonated phosphate, [H2 PO4 - ], (young = 11.7 ± 3.6 mm, old = 18.6 ± 2.1 mm) at the end of the exercise in old compared to young adults. The age-related increase in power loss during the fatiguing exercise was strongly associated with intracellular pH (r = -0.837), [Pi ] (r = 0.917) and [H2 PO4 - ] (r = 0.930) at the end of the exercise. These data suggest that the age-related increase in fatigability during dynamic exercise has a bioenergetic basis and is explained by an increased accumulation of metabolites within the muscle.
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Affiliation(s)
- Christopher W Sundberg
- Department of Biological Sciences, Marquette University, Milwaukee, WI, USA.,Department of Physical Therapy, Marquette University, Milwaukee, WI, USA
| | - Robert W Prost
- Department of Radiology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Robert H Fitts
- Department of Biological Sciences, Marquette University, Milwaukee, WI, USA
| | - Sandra K Hunter
- Department of Physical Therapy, Marquette University, Milwaukee, WI, USA
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Sundberg CW, Fitts RH. Bioenergetic basis of skeletal muscle fatigue. CURRENT OPINION IN PHYSIOLOGY 2019; 10:118-127. [PMID: 31342000 DOI: 10.1016/j.cophys.2019.05.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Energetic demand from high-intensity exercise can easily exceed ATP synthesis rates of mitochondria leading to a reliance on anaerobic metabolism. The reliance on anaerobic metabolism results in the accumulation of intracellular metabolites, namely inorganic phosphate (Pi) and hydrogen (H+), that are closely associated with exercise-induced reductions in power. Cellular and molecular studies have revealed several steps where these metabolites impair contractile function demonstrating a causal role in fatigue. Elevated Pi or H+ directly inhibits force and power of the cross-bridge and decreases myofibrillar Ca2+ sensitivity, whereas Pi also inhibits Ca2+ release from the sarcoplasmic reticulum (SR). When both metabolites are elevated, they act synergistically to cause marked reductions in power, indicating that fatigue during high-intensity exercise has a bioenergetic basis.
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Affiliation(s)
- Christopher W Sundberg
- Department of Biological Sciences, Marquette University, Milwaukee, WI.,Department of Physical Therapy, Marquette University, Milwaukee, WI
| | - Robert H Fitts
- Department of Biological Sciences, Marquette University, Milwaukee, WI
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Bozic PR, Pazin N, Berjan Bacvarevic B. Evaluation of the torque-angular velocity relationship across various joint positions. J Sports Med Phys Fitness 2019; 59:1691-1699. [PMID: 31062543 DOI: 10.23736/s0022-4707.19.09615-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Standard neuromuscular assessment through a single value, such as the maximum voluntary torque, could be limited since it changes substantially with movement velocity and joint position and could not discern among force, velocity or power producing capacities of a specific muscle. Therefore, we aimed to evaluate the torque-angular velocity (T-AV) interchange across various joint positions. METHODS Knee extensors were tested in 40 physically active participants at six velocities between 30° and 180°/s. Both, linear and the second-order polynomial regression methods were applied on peak torque (TMAX) and angle specific torque outputs (between 80° to 20° of knee extension). RESULTS The obtained results suggest decline of the concentric torque as angular velocity increases (P<0.05). The obtained the T-AV relationship appears to be strong and linear for the most subjects (R2=0.74-0.97) and highly reliable (r>0.80) at least when the positions around the TMAX angle are considered. CONCLUSIONS The present study revealed that the T-AV relationship of knee extensors, observed from isokinetic tests conducted within a wide range of angular velocities, could be strong, linear and reliable. The results demonstrate that linear regression method could be feasible approach for evaluating individual muscle mechanical capacities.
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Affiliation(s)
- Predrag R Bozic
- Serbian Institute of Sport and Sports Medicine, Belgrade, Serbia - .,Faculty of Sport and Physical Education, University of Montenegro, Niksic, Montenegro -
| | - Nemanja Pazin
- Faculty of Management in Sport, Alfa BK University, Belgrade, Serbia
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Age Does Not Attenuate Maximal Velocity Adaptations in the Ipsilateral and Contralateral Limbs During Unilateral Resistance Training. J Aging Phys Act 2019; 27:1-8. [DOI: 10.1123/japa.2017-0297] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Chuang YF, Chen CC, Hsu MJ, Huang NJ, Huang YZ, Chan HL, Chang YJ. Age related changes of the motor excitabilities and central and peripheral muscle strength. J Electromyogr Kinesiol 2018; 44:132-138. [PMID: 30640164 DOI: 10.1016/j.jelekin.2018.12.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 11/09/2018] [Accepted: 12/23/2018] [Indexed: 12/18/2022] Open
Abstract
INTRODUCTION The purpose was to investigate the age effects on central versus peripheral sources of strength, fatigue, and central neural excitabilities. METHODS 42 healthy subjects were recruited as young group (23.73 ± 2.15 years; n = 26) and middle-aged group (57.25 ± 4.57 years; n = 16). Maximum voluntary contraction force (MVC), voluntary activation level (VA), and twitch force of quadriceps were evaluated to represent general, central, and peripheral strengths. Central and peripheral fatigue indexes were evaluated using femoral nerve electrical stimulation. Cortical excitabilities were evaluated using transcranial magnetic stimulation (TMS). RESULTS The middle-aged group had lower MVC and twitch force of quadriceps, but not VA, than young group. No between group differences were found in fatigue indexes. The cortical excitability in middle-aged group was different from young group in paired TMS with inter-stimulus interval of 7 ms. CONCLUSION The age-related strength loss at early stage was primarily caused by peripheral muscular strength. The deviation of central neural excitability can be detected but the activation level was not impaired in middle-age adults.
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Affiliation(s)
- Yu-Fen Chuang
- School of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, and Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan; Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan
| | - Chih-Chung Chen
- School of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, and Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan; Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan
| | - Miao-Ju Hsu
- Department of Physical Therapy, College of Health Science, Kaohsiung Medical University; Department of Physical Medicine and Rehabilitation, and Department of Medical Research, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Nan-Jing Huang
- School of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, and Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan
| | - Ying-Zu Huang
- Department of Neurology, Chang Gung Memorial Hospital, Linkou, and School of Medicine, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Neuroscience Research Center, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan
| | - Hsiao-Lung Chan
- Neuroscience Research Center, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan; Department of Electrical Engineering, College of Engineering, Chang Gung University, Taoyuan, Taiwan.
| | - Ya-Ju Chang
- School of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, and Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan; Neuroscience Research Center, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan.
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Alota Ignacio Pereira V, Augusto Barbieri F, Moura Zagatto A, Cezar Rocha Dos Santos P, Simieli L, Augusto Barbieri R, Pivetta Carpes F, Teresa Bucken Gobbi L. Muscle Fatigue Does Not Change the Effects on Lower Limbs Strength Caused by Aging and Parkinson's Disease. Aging Dis 2018; 9:988-998. [PMID: 30574412 PMCID: PMC6284767 DOI: 10.14336/ad.2018.0203] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 02/03/2018] [Indexed: 12/20/2022] Open
Abstract
The aim of this study was to determine the impact of aging and Parkinson’s disease (PD) on lower limb muscle strength before and after muscle fatigue. One hundred thirty-five individuals were distributed over seven groups according to their age (20, 30, 40, 50, 60, 70 years old) and disease. Participants performed maximum voluntary isometric contractions (MVIC) in a leg press device followed by the muscle fatigue protocol (repeated sit-to-stand task). Immediately after muscle fatigue (less than 2 min), the MVIC were repeated. The peak force, peak rate of force development (first 50, 100, 200 ms), and root mean square and peak values of the vastus lateralis and vastus medialis muscle activity during MVIC were calculated before and after muscle fatigue. We found more pronounced reductions in lower limb muscle strength parameters (lower limb force, RFD-100 and RFD-200 - p<0.05) in individuals over 50 years of age and with PD. In addition, there was an inverse relation between aging and lower limb muscle strength parameters. The main findings were the lack of changes in peak force, RFDs and muscle activity of the vastus lateralis and vastus medialis after muscle fatigue according to aging and PD, and similar lower limb muscle strength parameters (before and after muscle fatigue) and effect of muscle fatigue in PD compared to the aged groups (60 and 70 years old groups).
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Affiliation(s)
- Vinicius Alota Ignacio Pereira
- 1Human Movement Research Laboratory (MOVI-LAB), Department of Physical Education, Sao Paulo State University (Unesp), Bauru, Brazil
| | - Fabio Augusto Barbieri
- 1Human Movement Research Laboratory (MOVI-LAB), Department of Physical Education, Sao Paulo State University (Unesp), Bauru, Brazil
| | - Alessandro Moura Zagatto
- 1Human Movement Research Laboratory (MOVI-LAB), Department of Physical Education, Sao Paulo State University (Unesp), Bauru, Brazil
| | - Paulo Cezar Rocha Dos Santos
- 2Posture and Gait Studies Laboratory (LEPLO), Department of Physical Education, Sao Paulo State University (Unesp), Rio Claro, Brazil
| | - Lucas Simieli
- 1Human Movement Research Laboratory (MOVI-LAB), Department of Physical Education, Sao Paulo State University (Unesp), Bauru, Brazil
| | - Ricardo Augusto Barbieri
- 3Graduate Program in Physical Education and Sport at School of Physical Education and Sport of Ribeirao Preto (EEFERP), University of Sao Paulo, Centro Universitário Estacio de Ribeirao Preto, Brazil
| | - Felipe Pivetta Carpes
- 4Applied Neuromechanics Group, Laboratory of Neuromechanics, Federal University of Pampa, Uruguaiana, Brazil
| | - Lilian Teresa Bucken Gobbi
- 2Posture and Gait Studies Laboratory (LEPLO), Department of Physical Education, Sao Paulo State University (Unesp), Rio Claro, Brazil
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Mathern RM, Anhorn M, Uygur M. A novel method to assess rate of force relaxation: reliability and comparisons with rate of force development across various muscles. Eur J Appl Physiol 2018; 119:291-300. [DOI: 10.1007/s00421-018-4024-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Accepted: 10/20/2018] [Indexed: 01/12/2023]
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KRÜGER RENATAL, ABOODARDA SAIEDJALAL, SAMOZINO PIERRE, RICE CHARLESL, MILLET GUILLAUMEY. Isometric versus Dynamic Measurements of Fatigue: Does Age Matter? A Meta-analysis. Med Sci Sports Exerc 2018; 50:2132-2144. [DOI: 10.1249/mss.0000000000001666] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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48
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Sundberg CW, Hunter SK, Trappe SW, Smith CS, Fitts RH. Effects of elevated H + and P i on the contractile mechanics of skeletal muscle fibres from young and old men: implications for muscle fatigue in humans. J Physiol 2018; 596:3993-4015. [PMID: 29806714 PMCID: PMC6117549 DOI: 10.1113/jp276018] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Accepted: 04/27/2018] [Indexed: 01/09/2023] Open
Abstract
KEY POINTS The mechanisms responsible for the loss in muscle power and increased fatigability with ageing are unresolved. We show that the contractile mechanics of fibres from the vastus lateralis of old men were well-preserved compared to those of young men, but the selective loss of fast myosin heavy chain II muscle was strongly associated with age-related decrements in whole-muscle strength and power. We reveal that the combination of acidosis (H+ ) and inorganic phosphate (Pi ) is an important mediator of muscle fatigue in humans by inhibiting the low- to high-force state of the cross-bridge cycle and peak power, but the depressive effects of these ions on cross-bridge function were similar in fibres from young and old men. These findings suggest that the age-related loss in muscle power is primarily determined by the atrophy of fast fibres, but the age-related increased fatigability cannot be explained by an increased sensitivity of the cross-bridge to H+ and Pi . ABSTRACT The present study aimed to identify the mechanisms responsible for the loss in muscle power and increased fatigability with ageing by integrating measures of whole-muscle function with single fibre contractile mechanics. After adjusting for the 22% smaller muscle mass in old (73-89 years, n = 6) compared to young men (20-29 years, n = 6), isometric torque and power output of the knee extensors were, respectively, 38% and 53% lower with age. Fatigability was ∼2.7-fold greater with age and strongly associated with reductions in the electrically-evoked contractile properties. To test whether cross-bridge mechanisms could explain age-related decrements in knee extensor function, we exposed myofibres (n = 254) from the vastus lateralis to conditions mimicking quiescent muscle and fatiguing levels of acidosis (H+ ) (pH 6.2) and inorganic phosphate (Pi ) (30 mm). The fatigue-mimicking condition caused marked reductions in force, shortening velocity and power and inhibited the low- to high-force state of the cross-bridge cycle, confirming findings from non-human studies that these ions act synergistically to impair cross-bridge function. Other than severe age-related atrophy of fast fibres (-55%), contractile function and the depressive effects of the fatigue-mimicking condition did not differ in fibres from young and old men. The selective loss of fast myosin heavy chain II muscle was strongly associated with the age-related decrease in isometric torque (r = 0.785) and power (r = 0.861). These data suggest that the age-related loss in muscle strength and power are primarily determined by the atrophy of fast fibres, but the age-related increased fatigability cannot be explained by an increased sensitivity of the cross-bridge to H+ and Pi .
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Affiliation(s)
- Christopher W. Sundberg
- Exercise Science ProgramMilwaukeeWIUSA
- Clinical & Translational Rehabilitation Health Sciences ProgramDepartment of Physical TherapyMarquette UniversityMilwaukeeWIUSA
| | - Sandra K. Hunter
- Exercise Science ProgramMilwaukeeWIUSA
- Clinical & Translational Rehabilitation Health Sciences ProgramDepartment of Physical TherapyMarquette UniversityMilwaukeeWIUSA
| | - Scott W. Trappe
- Human Performance LaboratoryBall State UniversityMuncieINUSA
| | | | - Robert H. Fitts
- Department of Biological SciencesMarquette UniversityMilwaukeeWIUSA
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Looft JM, Herkert N, Frey-Law L. Modification of a three-compartment muscle fatigue model to predict peak torque decline during intermittent tasks. J Biomech 2018; 77:16-25. [PMID: 29960732 PMCID: PMC6092960 DOI: 10.1016/j.jbiomech.2018.06.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 05/18/2018] [Accepted: 06/09/2018] [Indexed: 01/16/2023]
Abstract
This study aimed to test whether adding a rest recovery parameter, r, to the analytical three-compartment controller (3CC) fatigue model (Xia and Frey Law, 2008) will improve fatigue estimates during intermittent contractions. The 3CC muscle fatigue model uses differential equations to predict the flow of muscle between three muscle states: Resting (MR), Active (MA), and Fatigued (MF). This model uses a feedback controller to match the active state to target loads and two joint-specific parameters: F, fatigue rate controlling flow from active to fatigued compartments) and R, the recovery rate controlling flow from the fatigued to the resting compartments. This model does well to predict intensity-endurance time curves for sustained isometric tasks. However, previous studies find when rest intervals are present that the model over predicts fatigue. Intermittent rest periods would allow for the occurrence of subsequent reactive vasodilation and post-contraction hyperemia. We hypothesize a modified 3CC-r fatigue model will improve predictions of force decay during intermittent contractions with the addition of a rest recovery parameter, r, to augment recovery during rest intervals, representing muscle re-perfusion. A meta-analysis compiling intermittent fatigue data from 63 publications reporting decline in peak torque (% torque decline) were used for comparison. The original model over-predicted fatigue development from 19 to 29% torque decline; the addition of a rest multiplier significantly improved fatigue estimates to 6-10% torque decline. We conclude the addition of a rest multiplier to the three-compartment controller fatigue model provides a physiologically consistent modification for tasks involving rest intervals, resulting in improved estimates of muscle fatigue.
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Affiliation(s)
- John M Looft
- Department of Physical Therapy, University of Minnesota, Minneapolis, MN 55455, USA; Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA 52242, USA
| | - Nicole Herkert
- Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA 52242, USA
| | - Laura Frey-Law
- Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA 52242, USA.
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Abstract
Performance fatigability is characterized as an acute decline in motor performance caused by an exercise-induced reduction in force or power of the involved muscles. Multiple mechanisms contribute to performance fatigability and originate from neural and muscular processes, with the task demands dictating the mechanisms. This review highlights that (1) inadequate activation of the motoneuron pool can contribute to performance fatigability, and (2) the demands of the task and the physiological characteristics of the population assessed, dictate fatigability and the involved mechanisms. Examples of task and population differences in fatigability highlighted in this review include contraction intensity and velocity, stability and support provided to the fatiguing limb, sex differences, and aging. A future challenge is to define specific mechanisms of fatigability and to translate these findings to real-world performance and exercise training in healthy and clinical populations across the life span.
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Affiliation(s)
- Sandra K Hunter
- Exercise Science Program, Department of Physical Therapy, Marquette University, Milwaukee, Wisconsin 53201
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