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Ortega DG, Smith RW, Arnett JE, Neltner TJ, Schmidt RJ, Johnson GO, Housh TJ. Are performance and perceived fatigability dependent on the anchor scheme of fatiguing isometric tasks in men? J Sports Med Phys Fitness 2024; 64:505-515. [PMID: 38436595 DOI: 10.23736/s0022-4707.24.15721-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2024]
Abstract
BACKGROUND Ratings of perceived exertion (RPE) can be used to regulate exercise intensity. This study examined the effect of anchor scheme on performance fatigability and neuromuscular responses following fatiguing forearm flexion tasks. METHODS Twelve men (age 20.9±2.2 years; height 179.8±5.3 cm; body mass 80.2±9.9 kg) performed sustained, isometric forearm flexion tasks to failure anchored to RPE=6 (RPEFT) and the torque (TRQFT) that corresponded to RPE=6. Pre-test and post-test maximal voluntary isometric contractions (MVIC) were performed to quantify changes in the amplitude (AMP) and mean power frequency (MPF) of the electromyographic (EMG) and mechanomyographic (MMG) signals. Neuromuscular efficiency (NME) was calculated by dividing normalized torque by normalized EMG AMP. A dependent t-test was used to assess the mean difference for time to task failure (TTF). Repeated measures ANOVAs were used to compare mean differences for performance fatigability and normalized neuromuscular parameters. RESULTS The RPEFT had a greater TTF than the TRQFT (P<0.001). MVIC and NME decreased from pre-test to post-test following the RPEFT and TRQFT (P<0.05) with no differences between anchor schemes. Following the TRQFT, normalized EMG MPF decreased from pre-test to post-test (P=0.004). Following the RPEFT, normalized MMG MPF increased from pre-test to post-test (P=0.021). There were no changes in normalized EMG AMP or MMG AMP (P>0.05). CONCLUSIONS These findings indicated anchor scheme-specific neuromuscular responses and TTF, despite no difference in performance fatigability. Furthermore, performance fatigability was likely due to peripheral fatigue (based on normalized EMG MPF and NME) following the TRQFT, but peripheral and central fatigue (based on normalized MMG MPF and NME) following the RPEFT.
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Affiliation(s)
- Dolores G Ortega
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska - Lincoln, Lincoln, NE, USA -
| | - Robert W Smith
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska - Lincoln, Lincoln, NE, USA
| | - Jocelyn E Arnett
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska - Lincoln, Lincoln, NE, USA
| | - Tyler J Neltner
- Department of Health and Human Performance, University of Wisconsin - Platteville, Platteville, WI, USA
| | - Richard J Schmidt
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska - Lincoln, Lincoln, NE, USA
| | - Glen O Johnson
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska - Lincoln, Lincoln, NE, USA
| | - Terry J Housh
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska - Lincoln, Lincoln, NE, USA
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Ortega DG, Housh TJ, Smith RW, Arnett JE, Neltner TJ, Schmidt RJ, Johnson GO. The Effects of Anchoring a Fatiguing Forearm Flexion Task to a High vs. Low Rating of Perceived Exertion on Torque and Neuromuscular Responses. J Strength Cond Res 2024; 38:e219-e225. [PMID: 38662889 DOI: 10.1519/jsc.0000000000004730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2024]
Abstract
ABSTRACT Ortega, DG, Housh, TJ, Smith, RW, Arnett, JE, Neltner, TJ, Schmidt, RJ, and Johnson, GO. The effects of anchoring a fatiguing forearm flexion task to a high versus low rating of perceived exertion on torque and neuromuscular responses. J Strength Cond Res 38(5): e219-e225, 2024-This study examined the torque and neuromuscular responses following sustained, isometric, forearm flexion tasks anchored to 2 ratings of perceived exertion (RPE). Nine men (mean ± SD: age = 21.0 ± 2.4 years; height = 179.5 ± 5.1 cm; body mass = 79.6 ± 11.4 kg) completed maximal voluntary isometric contractions (MVIC) before and after sustained, isometric, forearm flexion tasks to failure anchored to RPE = 2 and RPE = 8. The amplitude (AMP) and mean power frequency (MPF) of the electromyographic (EMG) signal were recorded from the biceps brachii. Normalized torque was divided by normalized EMG AMP to calculate neuromuscular efficiency (NME). A dependent t-test was used to assess the mean difference for time to task failure (TTF). Repeated-measures analysis of variances was used to compare mean differences for MVIC and normalized neuromuscular parameters. There was no significant difference in TTF between RPE = 2 and RPE = 8 (p = 0.713). The MVIC decreased from pretest to posttest at RPE = 2 (p = 0.009) and RPE = 8 (p = 0.003), and posttest MVIC at RPE = 8 was less than that at RPE = 2 (p < 0.001). In addition, NME decreased from pretest to posttest (p = 0.008). There was no change in normalized EMG AMP or EMG MPF (p > 0.05). The current findings indicated that torque responses were intensity specific, but TTF and neuromuscular responses were not. Furthermore, normalized EMG AMP and EMG MPF remained unchanged but NME decreased, likely due to peripheral fatigue and excitation-contraction coupling failure. Thus, this study provides information regarding the neuromuscular responses and mechanisms of fatigue associated with tasks anchored to RPE, which adds to the foundational understanding of the relationship between resistance exercise and the perception of fatigue.
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Affiliation(s)
- Dolores G Ortega
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska; and
| | - Terry J Housh
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska; and
| | - Robert W Smith
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska; and
| | - Jocelyn E Arnett
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska; and
| | - Tyler J Neltner
- Department of Health and Human Performance, University of Wisconsin-Platteville, Platteville, Wisconsin
| | - Richard J Schmidt
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska; and
| | - Glen O Johnson
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska; and
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Ortega DG, Housh TJ, Smith RW, Arnett JE, Neltner TJ, Anders JPV, Schmidt RJ, Johnson GO. Effects of a Sustained, Isometric Forearm Flexion Task to Failure on Torque and Neuromuscular Responses at 3 Elbow Joint Angles. J Strength Cond Res 2024; 38:e25-e33. [PMID: 38085633 DOI: 10.1519/jsc.0000000000004599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
ABSTRACT Ortega, DG, Housh, TJ, Smith, RW, Arnett, JE, Neltner, TJ, Anders, JPV, Schmidt, RJ, and Johnson, GO. The effects of a sustained, isometric forearm flexion task to failure on torque and neuromuscular responses at 3 elbow joint angles. J Strength Cond Res 38(1): e25-e33, 2024-This study examined the effects of a sustained, isometric forearm flexion task anchored to torque to task failure on maximal voluntary isometric contraction (MVIC) and neuromuscular responses at 3 elbow joint angles. Eleven women (mean ± SD: age = 20.8 ± 2.7 years, height = 169.3 ± 7.4 cm, body mass = 67.7 ± 6.9 kg) performed two 3s forearm flexion MVICs at elbow joint angles (JAs) of 75°, 100°, and 125° before and after a sustained, isometric forearm flexion task to failure at a fatiguing joint angle of 100° anchored to a torque value that corresponded to a rating of perceived exertion of 8 (RPE = 8). The amplitude (AMP) and mean power frequency (MPF) of the electromyographic (EMG) and mechanomyographic (MMG) signals were recorded from the biceps brachii. Repeated-measures ANOVAs were used to compare mean differences for MVIC and neuromuscular parameters. Collapsed across JAs, MVIC (p < 0.001) and EMG MPF (p = 0.006) pretest values were greater than posttest values. Collapsed across time, EMG MPF at JA75 was greater than JA100 (p < 0.001) and JA125 (p < 0.001), and JA100 was greater (p = 0.007) than JA125. For EMG AMP, there was a fatigue-induced decrease at JA75 (p = 0.003). For neuromuscular efficiency (NME = normalized torque/normalized EMG AMP), there were decreases from pretest to posttest at JA100 (p = 0.002) and JA125 (p = 0.008). There were no significant interactions or main effects for MMG AMP and MMG MPF. From these findings, it was hypothesized that the decline in MVICs at JA75, JA100, and JA125 was due to fatigue-induced metabolic perturbations that resulted in JA-specific neuromuscular responses. Thus, neuromuscular parameters may provide insight into the JA-specific mechanisms of fatigue.
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Affiliation(s)
- Dolores G Ortega
- Department of Nutrition and Health Sciences, Exercise Physiology Laboratory, University of Nebraska-Lincoln, Lincoln, Nebraska; and
| | - Terry J Housh
- Department of Nutrition and Health Sciences, Exercise Physiology Laboratory, University of Nebraska-Lincoln, Lincoln, Nebraska; and
| | - Robert W Smith
- Department of Nutrition and Health Sciences, Exercise Physiology Laboratory, University of Nebraska-Lincoln, Lincoln, Nebraska; and
| | - Jocelyn E Arnett
- Department of Nutrition and Health Sciences, Exercise Physiology Laboratory, University of Nebraska-Lincoln, Lincoln, Nebraska; and
| | - Tyler J Neltner
- Department of Nutrition and Health Sciences, Exercise Physiology Laboratory, University of Nebraska-Lincoln, Lincoln, Nebraska; and
| | - John Paul V Anders
- Department of Human Sciences, The Exercise Science Program, The Ohio State University, Columbus, Ohio
| | - Richard J Schmidt
- Department of Nutrition and Health Sciences, Exercise Physiology Laboratory, University of Nebraska-Lincoln, Lincoln, Nebraska; and
| | - Glen O Johnson
- Department of Nutrition and Health Sciences, Exercise Physiology Laboratory, University of Nebraska-Lincoln, Lincoln, Nebraska; and
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Smith RW, Housh TJ, Arnett JE, Anders JPV, Neltner TJ, Ortega DG, Schmidt RJ, Johnson GO. The Effects of Anchor Schemes on Performance Fatigability, Neuromuscular Responses and the Perceived Sensations That Contributed to Task Termination. J Funct Morphol Kinesiol 2023; 8:jfmk8020049. [PMID: 37218845 DOI: 10.3390/jfmk8020049] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 04/18/2023] [Accepted: 04/20/2023] [Indexed: 05/24/2023] Open
Abstract
The present study examined the effect of anchor schemes on the time to task failure (TTF), performance fatigability, neuromuscular responses, and the perceived sensations that contributed to task termination following the sustained, isometric forearm flexion tasks. Eight women completed sustained, isometric forearm flexion tasks anchored to RPE = 8 (RPEFT) and the torque (TRQFT) that corresponded to RPE = 8. The subjects performed pre-test and post-test maximal isometric contractions to quantify performance fatigability and changes in electromyographic amplitude (EMG AMP) and neuromuscular efficiency (NME). In addition, the subjects completed a post-test questionnaire (PTQ) to quantify the contributions of perceived sensations to task termination. Repeated measure ANOVAs were used to assess the mean differences for TTF, performance fatigability, and neuromuscular responses. Wilcoxon Signed Rank Tests were used to assess the differences between anchor schemes for the average values from the PTQ item scores. For TTF, the RPEFT was longer than the TRQFT (174.9 ± 85.6 vs. 65.6 ± 68.0 s; p = 0.006). Collapsed across the anchor scheme, there were decreases in torque (23.7 ± 5.5 Nm vs. 19.6 ± 4.9 Nm; p < 0.001) and NME (1.00 ± 0.00 vs. 0.76 ± 0.15; p = 0.003). There were no significant (p > 0.577) changes for EMG AMP. For the PTQ, there were no differences (p > 0.05) between anchor schemes. There were, however, inter-individual differences in the response scores. The current findings indicated that performance fatigability was likely due to peripheral fatigue (based on NME), not central fatigue (based on EMG AMP). Furthermore, the use of a PTQ may serve as a simple tool to assess the contributions of perceived sensations to task termination.
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Affiliation(s)
- Robert W Smith
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE 68510, USA
| | - Terry J Housh
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE 68510, USA
| | - Jocelyn E Arnett
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE 68510, USA
| | - John Paul V Anders
- The Exercise Science Program, Department of Human Sciences, The Ohio State University, Columbus, OH 43017, USA
| | - Tyler J Neltner
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE 68510, USA
| | - Dolores G Ortega
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE 68510, USA
| | - Richard J Schmidt
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE 68510, USA
| | - Glen O Johnson
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE 68510, USA
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Smith RW, Housh TJ, Arnett JE, Anders JPV, Neltner TJ, Ortega DG, Schmidt RJ, Johnson GO. Utilizing the RPE-Clamp model to examine interactions among factors associated with perceived fatigability and performance fatigability in women and men. Eur J Appl Physiol 2023; 123:1397-1409. [PMID: 36856798 DOI: 10.1007/s00421-023-05163-x] [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: 11/02/2022] [Accepted: 02/17/2023] [Indexed: 03/02/2023]
Abstract
PURPOSE The purpose of the present study was to examine the interactions between perceived fatigability and performance fatigability in women and men by utilizing the RPE-Clamp model to assess the fatigue-induced effects of a sustained, isometric forearm flexion task anchored to RPE = 8 on time to task failure (TTF), torque, and neuromuscular responses. METHODS Twenty adults (10 men and 10 women) performed two, 3 s forearm flexion maximal voluntary isometric contractions (MVICs) followed by a sustained, isometric forearm flexion task anchored to RPE = 8 using the OMNI-RES (0-10) scale at an elbow joint angle of 100°. Electromyographic amplitude (EMG AMP) was recorded from the biceps brachii. Torque and EMG AMP values resulting from the sustained task were normalized to the pretest MVIC. Neuromuscular efficiency was defined as NME = normalized torque/normalized EMG AMP. Mixed factorial ANOVAs and Bonferroni corrected dependent t tests and independent t tests were used to examine differences across time and between sex for torque and neuromuscular parameters. RESULTS There were no differences between the women and men for the fatigue-induced decreases in torque, EMG AMP, or NME, and the mean decreases (collapsed across sex) were 50.3 ± 8.6 to 2.8 ± 2.9% MVIC, 54.7 ± 12.0 to 19.6 ± 5.3% MVIC, and 0.94 ± 0.19 to 0.34 ± 0.16, respectively. Furthermore, there were no differences between the women and men for TTF (251.8 ± 74.1 vs. 258.7 ± 77.9 s). CONCLUSION The results suggested that the voluntary reductions in torque to maintain RPE and the decreases in NME were likely due to group III/IV afferent feedback from peripheral fatigue that resulted in excitation-contraction coupling failure.
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Affiliation(s)
- Robert W Smith
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, 68510, USA.
- , 840 N 14th Street, Lincoln, NE, 68508, USA.
| | - Terry J Housh
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, 68510, USA
| | - Jocelyn E Arnett
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, 68510, USA
| | - John Paul V Anders
- The Exercise Science Program, Department of Human Sciences, The Ohio State University, Columbus, OH, 43017, USA
| | - Tyler J Neltner
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, 68510, USA
| | - Dolores G Ortega
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, 68510, USA
| | - Richard J Schmidt
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, 68510, USA
| | - Glen O Johnson
- Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, 68510, USA
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Bergevin M, Steele J, Payen de la Garanderie M, Feral-Basin C, Marcora SM, Rainville P, Caron JG, Pageaux B. Pharmacological Blockade of Muscle Afferents and Perception of Effort: A Systematic Review with Meta-analysis. Sports Med 2023; 53:415-435. [PMID: 36318384 DOI: 10.1007/s40279-022-01762-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2022] [Indexed: 01/27/2023]
Abstract
BACKGROUND The perception of effort provides information on task difficulty and influences physical exercise regulation and human behavior. This perception differs from other-exercise related perceptions such as pain. There is no consensus on the role of group III/IV muscle afferents as a signal processed by the brain to generate the perception of effort. OBJECTIVE The aim of this meta-analysis was to investigate the effect of pharmacologically blocking muscle afferents on the perception of effort. METHODS Six databases were searched to identify studies measuring the ratings of perceived effort during physical exercise, with and without pharmacological blockade of muscle afferents. Articles were coded based on the operational measurement used to distinguish studies in which perception of effort was assessed specifically (effort dissociated) or as a composite experience including other exercise-related perceptions (effort not dissociated). Articles that did not provide enough information for coding were assigned to the unclear group. RESULTS The effort dissociated group (n = 6) demonstrated a slight increase in ratings of perceived effort with reduced muscle afferent feedback (standard mean change raw, 0.39; 95% confidence interval 0.13-0.64). The group effort not dissociated (n = 2) did not reveal conclusive results (standard mean change raw, - 0.29; 95% confidence interval - 2.39 to 1.8). The group unclear (n = 8) revealed a slight ratings of perceived effort decrease with reduced muscle afferent feedback (standard mean change raw, - 0.27; 95% confidence interval - 0.50 to - 0.04). CONCLUSIONS The heterogeneity in results between groups reveals that the inclusion of perceptions other than effort in its rating influences the ratings of perceived effort reported by the participants. The absence of decreased ratings of perceived effort in the effort dissociated group suggests that muscle afferent feedback is not a sensory signal for the perception of effort.
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Affiliation(s)
- Maxime Bergevin
- École de kinésiologie et des sciences de l'activite physique (EKSAP), Faculté de médecine, Université́ de Montréal, Montreal, QC, Canada.,Centre de recherche de l'Institut universitaire de gériatrie de Montréal (CRIUGM), Montreal, Canada
| | - James Steele
- School of Sport, Health and Social Sciences, Southampton, UK
| | - Marie Payen de la Garanderie
- École de kinésiologie et des sciences de l'activite physique (EKSAP), Faculté de médecine, Université́ de Montréal, Montreal, QC, Canada.,Centre de recherche de l'Institut universitaire de gériatrie de Montréal (CRIUGM), Montreal, Canada
| | - Camille Feral-Basin
- École de kinésiologie et des sciences de l'activite physique (EKSAP), Faculté de médecine, Université́ de Montréal, Montreal, QC, Canada.,Centre de recherche de l'Institut universitaire de gériatrie de Montréal (CRIUGM), Montreal, Canada
| | - Samuele M Marcora
- Department of Biomedical and Neuromotor Sciences (DiBiNeM), University of Bologna, Bologna, Italy
| | - Pierre Rainville
- Centre de recherche de l'Institut universitaire de gériatrie de Montréal (CRIUGM), Montreal, Canada.,Département de stomatologie, Faculté de médecine dentaire, Université de Montréal, Montreal, QC, Canada
| | - Jeffrey G Caron
- École de kinésiologie et des sciences de l'activite physique (EKSAP), Faculté de médecine, Université́ de Montréal, Montreal, QC, Canada.,Centre de recherche interdisciplinaire en réadaptation du Montréal métropolitain, Montreal, QC, Canada
| | - Benjamin Pageaux
- École de kinésiologie et des sciences de l'activite physique (EKSAP), Faculté de médecine, Université́ de Montréal, Montreal, QC, Canada. .,Centre de recherche de l'Institut universitaire de gériatrie de Montréal (CRIUGM), Montreal, Canada. .,Centre interdisciplinaire de recherche sur le cerveau et l'apprentissage (CIRCA), Montreal, QC, Canada.
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Smith RW, Housh TJ, Anders JPV, Neltner TJ, Arnett JE, Schmidt RJ, Johnson GO. Application of the Ratings of Perceived Exertion-Clamp Model to Examine the Effects of Joint Angle on the Time Course of Torque and Neuromuscular Responses During a Sustained, Isometric Forearm Flexion to Task Failure. J Strength Cond Res 2022; 37:1023-1033. [PMID: 36730581 DOI: 10.1519/jsc.0000000000004357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Robert W Smith
- Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, Lincoln, Nebraska
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Noboa K, Keller J, Hergenrader K, Housh T, Anders JP, Neltner T, Schmidt R, Johnson G. Men Exhibit Greater Pain Pressure Thresholds and Times to Task Failure but Not Performance Fatigability Following Self-Paced Exercise. Percept Mot Skills 2021; 128:2326-2345. [PMID: 34313524 DOI: 10.1177/00315125211035028] [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] [Indexed: 01/14/2023]
Abstract
The purpose of the current study was to determine if, and to what extent, sex differences in performance fatigability after a sustained, bilateral leg extension, anchored to a moderate rating of perceived exertion (RPE), could be attributed to muscle size, muscular strength, or pain pressure threshold (PPT) in young, healthy adults. Thirty adults (men: n = 15, women: n = 15) volunteered to complete a sustained leg extension task anchored to RPE = 5 (10-point OMNI scale) as well as pretest and posttest maximal voluntary isometric contraction (MVIC) trials. The fatigue-induced decline in MVIC force was defined as performance fatigability. We used muscle cross-sectional area (mCSA) to quantify muscle size and a dolorimeter to assess PPT. The sustained task induced fatigue such that both men and women exhibited significant (p < 0.05) decreases in MVIC force from pretest to posttest (M = 113.3, SD =24.2 kg vs. M = 98.3, SD = 23.1 kg and M = 73.1, SD =14.5 kg vs. M = 64.1, SD = 16.2 kg, respectively), with no significant sex differences in performance fatigability (grand M = 12.6, SD =10.6%). Men, however, exhibited significantly (p < 0.05) longer time to task failure (TTF) than women (M = 166.1, SD =83.0 seconds vs. M = 94.6, SD =41.7) as well as greater PPT (M = 5.9, SD = 2.2 kg vs. M = 3.4, SD =1.1 kg). The only significant predictor of performance fatigability was PPT. In conclusion, differences in PPT, at least in part, mediate variations in TTF during self-paced exercise anchored to a specific RPE and resulting in performance fatigability.
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Affiliation(s)
- Karina Noboa
- Performance and Physique Enhancement Laboratory, Department of Educational and Psychological Studies, College of Education, University of South Florida, Tampa, Florida, United States
| | - Joshua Keller
- Department of Health, Kinesiology, and Sport, College of Education and Professional Studies, University of South Alabama, Mobile, United States
| | - Kipp Hergenrader
- Human Performance Laboratory, Department of Nutrition and Health Sciences, College of Education, University of Nebraska - Lincoln, Lincoln, United States
| | - Terry Housh
- Human Performance Laboratory, Department of Nutrition and Health Sciences, College of Education, University of Nebraska - Lincoln, Lincoln, United States
| | - John Paul Anders
- Human Performance Laboratory, Department of Nutrition and Health Sciences, College of Education, University of Nebraska - Lincoln, Lincoln, United States
| | - Tyler Neltner
- Human Performance Laboratory, Department of Nutrition and Health Sciences, College of Education, University of Nebraska - Lincoln, Lincoln, United States
| | - Richard Schmidt
- Human Performance Laboratory, Department of Nutrition and Health Sciences, College of Education, University of Nebraska - Lincoln, Lincoln, United States
| | - Glen Johnson
- Human Performance Laboratory, Department of Nutrition and Health Sciences, College of Education, University of Nebraska - Lincoln, Lincoln, United States
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Self-Regulated Force and Neuromuscular Responses During Fatiguing Isometric Leg Extensions Anchored to a Rating of Perceived Exertion. Appl Psychophysiol Biofeedback 2020; 44:343-350. [PMID: 31494754 DOI: 10.1007/s10484-019-09450-2] [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] [Indexed: 12/27/2022]
Abstract
The purpose of the study was to examine the fatigue-related patterns of responses for electromyography (EMG), mechanomyography (MMG), and force during a sustained isometric muscle action anchored to RPE = 5. Ten men (22.9 ± 2.0 year) performed maximal voluntary isometric contractions (MVIC) prior to and following an isometric leg extension muscle action, which was sustained for a maximal time-limit of 5 min or until it could not be maintained at RPE = 5 (actual time-limit). EMG amplitude (AMP), EMG mean power-frequency (MPF), MMG AMP, MMG MPF, and force values were determined every 5% of the actual time-limit. Regression analyses were used to examine the neuromuscular parameters and force responses, and a t test was used to examine MVIC. The pretest MVIC (62.4 ± 14.3 kg) was significantly (p < 0.001; d = 1.07) greater than posttest (47.9 ± 12.8 kg). The percent decline in force during the sustained isometric muscle action was 47.5 ± 19.6%, and there was a significant, negative force versus time relationship (p < 0.001; R = - 0.980). There was a significant, negative EMG AMP versus time relationship (p < 0.001; R = -0.789), but no significant (p > 0.05) relationships for EMG MPF, MMG AMP, or MMG MPF versus time. The findings indicated that it was necessary to reduce force and EMG AMP to maintain RPE = 5. We hypothesize that the maintenance of RPE = 5 was initially accomplished by an anticipatory feedforward mechanism and then continuous integrations of afferent feedback, which resulted in reductions of EMG AMP and force, due to reductions in neural drive, to attenuate the impact of metabolic byproducts.
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Keller JL, Housh TJ, Hill EC, Smith CM, Schmidt RJ, Johnson GO. Sex-Related Differences in Performance Fatigability Independent of Blood Flow Following a Sustained Muscle Action at a Low Perceptual Intensity. ACTA ACUST UNITED AC 2020. [DOI: 10.1007/s42978-020-00052-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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11
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Keller JL, Housh TJ, Hill EC, Smith CM, Schmidt RJ, Johnson GO. Are There Sex-Specific Neuromuscular or Force Responses to Fatiguing Isometric Muscle Actions Anchored to a High Perceptual Intensity? J Strength Cond Res 2019; 36:156-161. [PMID: 31860532 DOI: 10.1519/jsc.0000000000003394] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Keller, JL, Housh, TJ, Hill, EC, Smith, CM, Schmidt, RJ, and Johnson, GO. Are there sex-specific neuromuscular or force responses to fatiguing isometric muscle actions anchored to a high perceptual intensity? J Strength Cond Res XX(X): 000-000, 2019-The purpose of this study was to use the ratings of perceived exertion (RPE) clamp model to examine sex-specific changes in neuromuscular responses and force after a sustained isometric leg extension muscle action anchored to RPE = 8. Twenty adults (10 men and 10 women) performed sustained, isometric leg extension muscle actions at RPE = 8. Electromyographic (EMG) and mechanomyographic signals were recorded from the dominant leg. Neuromuscular and force values resulting from the sustained muscle action were normalized to pretest maximal voluntary isometric contractions (MVICs). The level of significance set for the study was p ≤ 0.05. The pretest MVIC was significantly (p < 0.001) greater (averaged across sex) than posttest MVIC force (55.5 ± 10.0 vs. 47.6 ± 11.1 kg). There was a significant (p < 0.01) decrease from pretest (95.4 ± 7.7 Hz) to posttest (76.2 ± 5.9 Hz) in EMG mean power frequency (MPF) for the men. The normalized force (averaged across sex) decreased significantly (p < 0.001) from the initial timepoint (57.1 ± 16.4%) to the final timepoint (44.3 ± 15.7%) of the sustained muscle action. Normalized EMG MPF (averaged across sex) decreased significantly (p = 0.001) from the initial timepoint (96.4 ± 17.5%) to final timepoint (87.8 ± 18.1%). The men and women exhibited similar fatigue-induced changes in force and neuromuscular parameters; therefore, these findings did not indicate different sex-specific responses after the fatiguing task anchored to a high perception of exertion. The force corresponding to RPE = 8 did not match the anticipated value; so, RPE and percentages of MVIC cannot be used interchangeably, and sustained isometric muscle actions anchored to RPE may elicit unique neuromuscular adaptations.
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Affiliation(s)
- Joshua L Keller
- Human Performance Laboratory, Department of Nutrition and Health Sciences, College of Education and Human Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Terry J Housh
- Human Performance Laboratory, Department of Nutrition and Health Sciences, College of Education and Human Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Ethan C Hill
- Division of Kinesiology, School of Kinesiology and Physical Therapy, University of Central Florida, Orlando, Florida
| | - Cory M Smith
- Department of Kinesiology, College of Health Sciences, University of Texas at El Paso, El Paso, Texas 79968
| | - Richard J Schmidt
- Human Performance Laboratory, Department of Nutrition and Health Sciences, College of Education and Human Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Glen O Johnson
- Human Performance Laboratory, Department of Nutrition and Health Sciences, College of Education and Human Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska
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Lacerda LT, Marra-Lopes RO, Diniz RC, Lima FV, Rodrigues SA, Martins-Costa HC, Bemben MG, Chagas MH. Is Performing Repetitions to Failure Less Important Than Volume for Muscle Hypertrophy and Strength? J Strength Cond Res 2019; 34:1237-1248. [DOI: 10.1519/jsc.0000000000003438] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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