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Falk Neto JH, Faulhaber M, Kennedy MD. The Characteristics of Endurance Events with a Variable Pacing Profile-Time to Embrace the Concept of "Intermittent Endurance Events"? Sports (Basel) 2024; 12:164. [PMID: 38921858 PMCID: PMC11207974 DOI: 10.3390/sports12060164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 05/27/2024] [Accepted: 06/06/2024] [Indexed: 06/27/2024] Open
Abstract
A variable pacing profile is common in different endurance events. In these races, several factors, such as changes in elevation or race dynamics, lead participants to perform numerous surges in intensity. These surges are so frequent that certain events, such as cross-country (XC) skiing, mountain biking (MTB), triathlon, and road cycling, have been termed "intermittent endurance events". The characteristics of these surges vary depending on the sport: MTB and triathlon require athletes to perform numerous short (<10 s) bouts; XC skiing require periods of short- and moderate-(30 s to 2 min) duration efforts, while road cycling is comprised of a mix of short-, moderate-, and long-duration (>2 min) bouts. These bouts occur at intensities above the maximal metabolic steady state (MMSS), with many efforts performed at intensities above the athletes' maximal aerobic power or speed (MAP/MAS) (i.e., supramaximal intensities). Given the factors that influence the requirement to perform surges in these events, athletes must be prepared to always engage in a race with a highly stochastic pace. The aim of this review is to characterize the variable pacing profile seen in endurance events and to discuss how the performance of multiple maximal and supramaximal surges in intensity can affect how athletes fatigue during a race and influence training strategies that can lead to success in these races.
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Affiliation(s)
- Joao Henrique Falk Neto
- Athlete Health Lab., Faculty of Kinesiology, Sport and Recreation, University of Alberta, Edmonton, AB T6G 2R3, Canada;
| | - Martin Faulhaber
- Department of Sport Science, University of Innsbruck, 6020 Innsbruck, Austria;
| | - Michael D. Kennedy
- Athlete Health Lab., Faculty of Kinesiology, Sport and Recreation, University of Alberta, Edmonton, AB T6G 2R3, Canada;
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Zhang J, Murias JM, MacInnis MJ, Aboodarda SJ, Iannetta D. Performance and perceived fatigability across the intensity spectrum: role of muscle mass during cycling. Am J Physiol Regul Integr Comp Physiol 2024; 326:R472-R483. [PMID: 38557152 DOI: 10.1152/ajpregu.00272.2023] [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: 12/05/2023] [Revised: 03/19/2024] [Accepted: 03/28/2024] [Indexed: 04/04/2024]
Abstract
The role of muscle mass in modulating performance and perceived fatigability across the entire intensity spectrum during cycling remains unexplored. We hypothesized that at task failure (Tlim), muscle contractile function would decline more following single- (SL) versus double-leg (DL) cycling within severe and extreme intensities, but not moderate and heavy intensities. After DL and SL ramp-incremental tests, on separate days, 11 recreationally active males (V̇o2max: 49.5 ± 7.7 mL·kg-1·min-1) completed SL and DL cycling until Tlim within each intensity domain. Power output for SL trials was set at 60% of the corresponding DL trial. Before and immediately after Tlim, participants performed an isometric maximal voluntary contraction (MVC) coupled with one superimposed and three resting femoral nerve stimulations [100 Hz; 10 Hz; single twitch (Qtw)] to measure performance fatigability. Perceived fatigue, leg pain, dyspnea, and effort were collected during trials. Tlim within each intensity domain was not different between SL and DL (all P > 0.05). MVC declined more for SL versus DL following heavy- (-42 ± 16% vs. -30 ± 18%; P = 0.011) and severe-intensity cycling (-41 ± 12% vs. -31 ± 15%; P = 0.036). Similarly, peak Qtw force declined more for SL following heavy- (-31 ± 12% vs. -22 ± 10%; P = 0.007) and severe-intensity cycling (-49 ± 13% vs. -40 ± 7%; P = 0.048). Except for heavy intensity, voluntary activation reductions were similar between modes. Similarly, except for dyspnea, which was lower for SL versus DL across all domains, ratings of fatigue, pain, and effort were similar at Tlim between exercise modes. Thus, the amount of muscle mass modulates the extent of contractile function impairment in an intensity-dependent manner.NEW & NOTEWORTHY We investigated the modulatory role of muscle mass on performance and perceived fatigability across the entire intensity spectrum. Despite similar time-to-task failure, single-leg cycling resulted in greater impairments in muscle contractile function within the heavy- and severe-intensity domains, but not the moderate- and extreme-intensity domains. Perceived fatigue, pain, and effort were similar between cycling modes. This indicates that the modulatory role of muscle mass on the extent of performance fatigability is intensity domain-dependent.
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Affiliation(s)
- Jenny Zhang
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Juan M Murias
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | - Martin J MacInnis
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Saied J Aboodarda
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Danilo Iannetta
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
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3
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Hammer SM, Sears KN, Montgomery TR, Olmos AA, Hill EC, Trevino MA, Dinyer-McNeely TK. Sex differences in muscle contraction-induced limb blood flow limitations. Eur J Appl Physiol 2024; 124:1121-1129. [PMID: 37889287 DOI: 10.1007/s00421-023-05339-5] [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: 06/27/2023] [Accepted: 10/04/2023] [Indexed: 10/28/2023]
Abstract
PURPOSE To determined sex differences in absolute- and %-reductions in blood flow during intermittent muscular contractions as well as relationships between blood flow reductions and time to task failure (TTF). METHODS Thirteen males (25 ± 4 years) and 13 females (22 ± 5 years) completed intermittent isometric trapezoidal forearm flexion at 50% maximal voluntary contraction until task failure. Doppler ultrasound was used to measure brachial artery blood flow (BABF) during the 12-s plateau phase and 12-s relaxation phase. RESULTS Target torque was less in females than males (24 ± 5 vs. 42 ± 7 Nm; p < 0.001); however, TTF was not different between sexes (F: 425 ± 187 vs. M: 401 ± 158 s; p = 0.72). Relaxation-phase BABF at end-exercise was less in females than males (435 ± 161 vs. 937 ± 281 mL/min; p < 0.001) but contraction-phase BABF was not different (127 ± 46 vs. 190 ± 99 mL/min; p = 0.42). Absolute- and %-reductions in BABF by contraction were less in females than males (309 ± 146 vs. 747 ± 210 mL/min and 69 ± 10 vs. 80% ± 6%, respectively; both p < 0.01) and were associated with target torque independent of sex (r = 0.78 and 0.56, respectively; both p < 0.01). Absolute BABF reduction per target torque (mL/min/Nm) and TTF were positively associated in males (r = 0.60; p = 0.031) but negatively associated in females (r = - 0.61; p = 0.029). CONCLUSIONS This study provides evidence that females incur less proportional reduction in limb blood flow from muscular contraction than males at a matched relative intensity suggesting females may maintain higher levels of muscle oxygen delivery and metabolite removal than males across the contraction-relaxation cycle of intermittent exercise.
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Affiliation(s)
- Shane M Hammer
- School of Kinesiology, Applied Health, and Recreation, Oklahoma State University, Stillwater, OK, USA.
| | - Kylie N Sears
- School of Kinesiology, Applied Health, and Recreation, Oklahoma State University, Stillwater, OK, USA
| | - Tony R Montgomery
- School of Kinesiology, Applied Health, and Recreation, Oklahoma State University, Stillwater, OK, USA
| | - Alex A Olmos
- School of Kinesiology, Applied Health, and Recreation, Oklahoma State University, Stillwater, OK, USA
| | - Ethan C Hill
- School of Kinesiology and Rehabilitation Sciences, University of Central Florida, Orlando, FL, USA
| | - Michael A Trevino
- School of Kinesiology, Applied Health, and Recreation, Oklahoma State University, Stillwater, OK, USA
| | - Taylor K Dinyer-McNeely
- School of Kinesiology, Applied Health, and Recreation, Oklahoma State University, Stillwater, OK, USA
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4
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Alexander AM, Hurla LM, Didier KD, Hammer SM, Rollins KS, Barstow TJ. Sex differences in the intensity-duration relationships of the severe- and extreme-intensity exercise domains. Eur J Sport Sci 2023; 23:2221-2231. [PMID: 37199235 PMCID: PMC10615677 DOI: 10.1080/17461391.2023.2215723] [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] [Indexed: 05/19/2023]
Abstract
Extreme-intensity exercise is described by W'ext (analogous to J' for isometric exercise) that is smaller than W' of severe-intensity exercise (W'sev) in males. Sex differences in exercise tolerance appear to diminish at near-maximal exercise, however, there is evidence of greater contributions of peripheral fatigue (i.e. potentiated twitch force; Qpot) in males during extreme-intensity exercise. Therefore, the current study tested the hypotheses that J'ext would not be different between males and females, however, males would exhibit a greater reduction in neuromuscular function (i.e. maximal voluntary contraction, MVC; Qpot) following extreme-intensity exercise. Seven males and 7 females completed three severe- (Tlim: 2-4 min, S3; 5-8 min, S2; 9-15 min, S1) and three extreme-intensity (70, 80, 90%MVC) knee-extension bouts. MVC and Qpot relative to baseline were compared at task failure and at 150 s of recovery. J'ext was significantly less than J'sev in males (2.4 ± 1.2kJ vs 3.9 ± 1.3kJ; p = 0.03) and females (1.6 ± 0.8kJ vs 2.9 ± 1.7kJ; p = 0.05); however, there were no sex differences in J'ext or J'sev. MVC (%Baseline) was greater at task failure following extreme-intensity exercise (76.5 ± 20.0% vs 51.5 ± 11.5% in males, 75.7 ± 19.4% vs 66.7 ± 17.4% in females), but was not different at 150 s of recovery (95.7 ± 11.8% in males, 91.1 ± 14.2% in females). Reduction in Qpot, however, was greater in males (51.9 ± 16.3% vs 60.6 ± 15.5%) and was significantly correlated with J'ext (r2 = 0.90, p < 0.001). Although there were no differences in the magnitude of J'ext, differences in MVC and Qpot are evidence of sex-specific responses and highlight the importance of appropriately characterizing exercise intensity regarding exercise domains when comparing physiological responses in males and females.Highlights We have previously shown evidence that extreme-intensity dynamic exercise is described by W'ext in males and smaller than W'sev. We currently tested for potential sex differences in J'ext (isometric analogue to W') and neuromuscular responses (i.e. maximal voluntary contraction, MVC; potentiated twitch force, Qpot) during extreme-intensity exercise.J'ext and extreme-intensity exercise tolerance was not different between males and females. The reduction in MVC was not different across extreme-intensity exercise across males and females, whereas the reduction in Qpot was greater in males following all extreme-intensity exercises, although not after exercise at 90%MVC.Together, although extreme-intensity exercise tolerance is not different, these data highlight differences in the contributing mechanisms of fatigue during severe- and extreme-intensity exercise between males and females.
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Affiliation(s)
- Andrew M. Alexander
- Department of Kinesiology, Kansas State University, Manhattan KS, USA
- Department of Endocrinology, Diabetes, and Nutrition, Mayo Clinic, Rochester MN, USA
| | - Logan M. Hurla
- Department of Kinesiology, Kansas State University, Manhattan KS, USA
| | - Kaylin D. Didier
- Department of Kinesiology, Kansas State University, Manhattan KS, USA
- Department of Kinesiology, University of Wisconsin-Madison, Madison WI, USA
| | - Shane M. Hammer
- Department of Kinesiology, Kansas State University, Manhattan KS, USA
- School of Kinesiology, Applied Health, and Recreation, Oklahoma State University, Stillwater OK, USA
| | - Korynne S. Rollins
- Department of Kinesiology, Kansas State University, Manhattan KS, USA
- Department of Safety Pharmacology, Lab Corp, Madison WI, USA
| | - Thomas J. Barstow
- Department of Kinesiology, Kansas State University, Manhattan KS, USA
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5
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Ventura TP, Borszcz FK, Antunes D, Caputo F, Turnes T. Prediction of Exercise Tolerance in the Severe and Extreme Intensity Domains by a Critical Power Model. J Hum Kinet 2023; 89:113-122. [PMID: 38053952 PMCID: PMC10694707 DOI: 10.5114/jhk/170101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 04/05/2023] [Indexed: 12/07/2023] Open
Abstract
This study aimed to assess the predictive capability of different critical power (CP) models on cycling exercise tolerance in the severe- and extreme-intensity domains. Nineteen cyclists (age: 23.0 ± 2.7 y) performed several time-to-exhaustion tests (Tlim) to determine CP, finite work above CP (W'), and the highest constant work rate at which maximal oxygen consumption was attained (IHIGH). Hyperbolic power-time, linear power-inverse of time, and work-time models with three predictive trials were used to determine CP and W'. Modeling with two predictive trials of the CP work-time model was also used to determine CP and W'. Actual exercise tolerance of IHIGH and intensity 5% above IHIGH (IHIGH+5%) were compared to those predicted by all CP models. Actual IHIGH (155 ± 30 s) and IHIGH+5% (120 ± 26 s) performances were not different from those predicted by all models with three predictive trials. Modeling with two predictive trials overestimated Tlim at IHIGH+5% (129 ± 33 s; p = 0.04). Bland-Altman plots of IHIGH+5% presented significant heteroscedasticity by all CP predictions, but not for IHIGH. Exercise tolerance in the severe and extreme domains can be predicted by CP derived from three predictive trials. However, this ability is impaired within the extreme domain.
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Affiliation(s)
- Thiago Pereira Ventura
- Physical Effort Laboratory, Sports Center, Federal University of Santa Catarina, Florianopolis, Brazil
| | - Fernando Klitzke Borszcz
- Physical Effort Laboratory, Sports Center, Federal University of Santa Catarina, Florianopolis, Brazil
| | - Diego Antunes
- Physical Effort Laboratory, Sports Center, Federal University of Santa Catarina, Florianopolis, Brazil
| | - Fabrizio Caputo
- Human Performance Research Group, Center for Health Sciences and Sport, Santa Catarina State University, Florianopolis, Brazil
| | - Tiago Turnes
- Physical Effort Laboratory, Sports Center, Federal University of Santa Catarina, Florianopolis, Brazil
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6
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The effect of constant load cycling at extreme- and severe-intensity domains on performance fatigability and its determinants in young female. Sci Sports 2023. [DOI: 10.1016/j.scispo.2022.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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7
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Iannetta D, Zhang J, Murias JM, Aboodarda SJ. Neuromuscular and perceptual mechanisms of fatigue accompanying task failure in response to moderate-, heavy-, severe-, and extreme-intensity cycling. J Appl Physiol (1985) 2022; 133:323-334. [PMID: 35771217 DOI: 10.1152/japplphysiol.00764.2021] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A comprehensive characterization of neuromuscular and perceptual mechanisms of fatigue at task failure following exercise across the entire intensity spectrum is lacking. This study evaluated the extent of peripheral and central fatigue, and corresponding perceptual attributes, at task failure following cycling within the moderate-(MOD), heavy-(HVY), severe-(SVR), and extreme-(EXT) intensity domains. After a ramp-incremental test, eleven young males performed four constant-power output trials to the limit of tolerance (Tlim) at four distinct domain-specific workloads. These trials were preceded and followed by 5-s knee-extension maximal voluntary contractions (MVC) and femoral nerve electrical stimuli to quantify peripheral and central fatigue. Additionally, perceptual measures including ratings of global fatigue, legs pain, dyspnea and perceived effort (RPE) were also collected. At Tlim, reductions in MVC were independent of intensity (P>0.05). However, peripheral fatigue was greater following EXT and SVR and progressively, but distinctively, lower following HVY and MOD (P<0.05). Central fatigue was similar after SVR, HVY, and MOD, but absent after EXT (P<0.05). At Tlim, subjective ratings of global fatigue were progressively higher with lower exercise intensities, while ratings of legs pain and dyspnea were progressively higher with higher exercise intensities. On the other hand, RPE was maximal following HVY, SVR, and EXT, but not MOD. The findings demonstrate that at Tlim the extent of peripheral fatigue is highly domain-specific whereas the extent of central fatigue is not. Sensations such as fatigue, pain, and dyspnea may integrate with mechanisms of sense of effort to determine task failure in a manner specific to each intensity domain.
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Affiliation(s)
- Danilo Iannetta
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Jenny Zhang
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Juan M Murias
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
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8
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Alexander AM, Hammer SM, Didier KD, Huckaby LM, Barstow TJ. Neuromuscular recovery from severe- and extreme-intensity exercise in men and women. Appl Physiol Nutr Metab 2022; 47:458-468. [PMID: 35020495 DOI: 10.1139/apnm-2021-0407] [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]
Abstract
Maximal voluntary contraction force (MVC), potentiated twitch force (Qpot), and voluntary activation (%VA) recover to baseline within 90 s following extreme-intensity exercise. However, methodological limitations mask important recovery kinetics. We hypothesized reductions in MVC, Qpot, and %VA at task failure following extreme-intensity exercise would be less than following severe-intensity exercise, and Qpot and MVC following extreme-intensity exercise would show significant recovery within 120 s but remain depressed following severe-intensity exercise. Twelve subjects (6 men) completed 2 severe-intensity (40, 50% MVC) and 2 extreme-intensity (70, 80% MVC) isometric knee-extension exercise bouts to task failure (Tlim). Neuromuscular function was measured at baseline, Tlim, and through 150 s of recovery. Each intensity significantly reduced MVC and Qpot compared with baseline. MVC was greater at Tlim (p < 0.01) and at 150 s of recovery (p = 0.004) following exercise at 80% MVC compared with severe-intensity exercise. Partial recovery of MVC and Qpot were detected within 150 s following Tlim for each exercise intensity; Qpot recovered to baseline values within 150 s of recovery following exercise at 80% MVC. No differences in %VA were detected pre- to post-exercise or across recovery for any intensity. Although further analysis showed sex-specific differences in MVC and Qpot, future studies should closely examine sex-dependent responses to extreme-intensity exercise. It is clear, however, that these data reinforce that mechanisms limiting exercise tolerance during extreme-intensity exercise recover quickly. Novelty: Severe- and extreme-intensity exercise cause independent responses in fatigue accumulation and the subsequent recovery time courses. Recovery of MVC and Qpot occurs much faster following extreme-intensity exercise in both men and women.
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Affiliation(s)
- Andrew M Alexander
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA.,Department of Kinesiology, Kansas State University, Manhattan, KS, USA
| | - Shane M Hammer
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA.,Department of Kinesiology, Kansas State University, Manhattan, KS, USA
| | - Kaylin D Didier
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA.,Department of Kinesiology, Kansas State University, Manhattan, KS, USA
| | - Lillie M Huckaby
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA.,Department of Kinesiology, Kansas State University, Manhattan, KS, USA
| | - Thomas J Barstow
- Department of Kinesiology, Kansas State University, Manhattan, KS, USA.,Department of Kinesiology, Kansas State University, Manhattan, KS, USA
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9
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Abdalla LHP, Broxterman RM, Barstow TJ, Greco CC, Denadai BS. W' reconstitution rate at different intensities above critical torque: the role of muscle size and maximal strength. Exp Physiol 2021; 106:1909-1921. [PMID: 34288192 DOI: 10.1113/ep089638] [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: 04/06/2021] [Accepted: 07/16/2021] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Do muscle size, maximal force and exercise intensity influence the recovery time constant for the finite impulse above critical torque (τIET' )? What is the main finding and its importance? Muscle size and maximal strength have different influences on the parameters of the hyperbolic torque-time to task failure relationship. Greater muscle size and maximal strength, as well as exercise at an intensity of 60% MVC, prolong τIET' during intermittent isometric exercise. ABSTRACT Muscle perfusion and O2 delivery limitations through muscle force generation appear to play a major role in defining the hyperbolic torque-time to task failure (Tlim ) relationship. Therefore, we aimed to determine the influence of muscle size and maximal strength on the recovery time constant for the finite impulse above critical torque (τIET' ). Ten men participated in the study and performed intermittent isometric tests until task-failure (Tlim ) for the knee-extensors (KE) (35% and 60% maximal voluntary contraction (MVC)) and plantar flexors (PF) (60% MVC). The τIET' was determined for each of these Tlim tests using the IET'BAL model. The IET' (9738 ± 3080 vs. 2959 ± 1289 N m s) and end-test torque (ET)(84.5 ± 7.1 vs. 74.3 ± 12.7 N m) were significantly lower for PF compared to KE (P < 0.05). Exercise tolerance (Tlim ) was significantly longer for PF (239 ± 81 s) than KE (150 ± 55 s) at 60% MVC, and significantly longer for KE at 35% MVC (641 ± 158 s) than 60% MVC. The τIET' was significantly faster at 35% MVC (641 ± 177 s) than 60% MVC (1840 ± 354 s) for KE, both of which were significantly slower than PF at 60% MVC (317 ± 102 s). This study showed that τIET' during intermittent isometric exercise is slower with greater muscle size and maximal strength.
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Affiliation(s)
| | - Ryan Michael Broxterman
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.,Geriatric Research, Education and Clinical Center, VA Medical Center, Salt Lake City, UT, USA
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10
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Hammer SM, Alexander AM, Didier KD, Barstow TJ. Influence of blood flow occlusion on muscular recruitment and fatigue during maximal‐effort small muscle‐mass exercise. J Physiol 2020; 598:4293-4306. [DOI: 10.1113/jp279925] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 07/22/2020] [Indexed: 11/08/2022] Open
Affiliation(s)
- Shane M. Hammer
- Department of Kinesiology Kansas State University Manhattan KS USA
| | | | - Kaylin D. Didier
- Department of Kinesiology Kansas State University Manhattan KS USA
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11
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Alexander AM, Didier KD, Hammer SM, Dzewaltowski AC, Kriss KN, Lovoy GM, Hammer JL, Smith JR, Ade CJ, Broxterman RM, Barstow TJ. Exercise tolerance through severe and extreme intensity domains. Physiol Rep 2020; 7:e14014. [PMID: 30825269 PMCID: PMC6397101 DOI: 10.14814/phy2.14014] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 02/01/2019] [Indexed: 01/24/2023] Open
Abstract
The power‐duration relationship accurately predicts exercise tolerance for constant power exercise performed in the severe intensity domain. However, the accuracy of the prediction of time to task failure (Tlim) is currently unclear for work rates (WR) above severe intensities; that is, within the extreme intensity domain (Tlim < 2 min). We hypothesized that Tlim would be shorter for WRs within the extreme intensity domain than predicted from the linear 1/time relationship of the severe intensity domain which would suggest mechanisms limiting exercise are different between intensity domains. Six men completed 7 knee‐extension tests. Tlim of extreme intensity exercise (60%, 70%, 80%, and 90% 1RM; Tlim < 2 min) were compared to the predicted Tlim from the slope of the S1–S3 (Tlim ≥ 2–15 min) regression. Twitch force (Qtw) and maximal voluntary contraction (MVC) were measured on the right vastus lateralis before and after each test. Tlim at 70–90% 1RM were shorter than the Tlim predicted by the severe domain 1/time model (P < 0.05); however, Tlim at 60% 1RM was not different than the predicted severe Tlim, suggesting the mechanisms limiting extreme exercise manifest ≥60% 1RM. A significant linear relationship for 60–90% 1RM was observed which suggested a curvature constant unique to the extreme domain (Wext′) that was smaller than the W ′ of the severe domain (1.5 ± 0.6 vs. 5.9 ± 1.5 kJ, P < 0.001). Qtw and MVC were significantly decreased following severe exercise, however, Qtw and MVC were not significantly decreased following 80% and 90% 1RM, giving evidence that mechanisms causing task failure were recovered by the time post‐exercise measurements were made (~90 sec).
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Affiliation(s)
| | - Kaylin D Didier
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Shane M Hammer
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | | | - Karly N Kriss
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Garrett M Lovoy
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Joseph L Hammer
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Joshua R Smith
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Carl J Ade
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Ryan M Broxterman
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
| | - Thomas J Barstow
- Department of Kinesiology, Kansas State University, Manhattan, Kansas
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