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Ambrozy CA, Hawes NE, Hayden OL, Sortz I, Malek MH. Caffeine Expectancy Does Not Influence the Physical Working Capacity at the Fatigue Threshold. J Strength Cond Res 2024; 38:1056-1062. [PMID: 38781467 DOI: 10.1519/jsc.0000000000004742] [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: 05/25/2024]
Abstract
ABSTRACT Ambrozy, CA, Hawes, NE, Hayden, OL, Sortzi, I, and Malek, MH. Caffeine expectancy does not influence the physical working capacity at the fatigue threshold. J Strength Cond Res 38(6): 1056-1062, 2024-The placebo effect occurs when a desired outcome is experienced due to the belief that a treatment is effective, even in the absence of an active ingredient. One explanation for this effect is based on a person's expectations of a drug or supplement. Although caffeine's effects on sports performance have been studied, little is known about how expectations of caffeine affect neuromuscular fatigue during continuous muscle action. The physical working capacity at the fatigue threshold (PWCFT) can be used to assess neuromuscular fatigue noninvasively using surface electromyography. Thus, the purpose of this study was to investigate whether caffeine expectancy influences PWCFT. We hypothesized that regardless of expectancy, caffeine consumption would delay neuromuscular fatigue. The study involved 8 healthy college-aged men (mean ± SEM: age, 25.6 ± 1.0 years) who visited the laboratory on 4 occasions, each separated by 7 days. The subjects completed 4 experimental conditions, in random order, where they were told that they were consuming caffeine or placebo and either received caffeine or placebo. After consuming the drink, the subjects remained in the laboratory for an hour and then performed an incremental exercise test. The results showed that the condition where subjects were told that they were consuming caffeine and received caffeine had significantly higher mean values for maximal power output (F(3, 21) = 11.75; p < 0.001), PWCFT (F(3, 21) = 12.28; p < 0.001), PWCFT (%maximal power output; F(3, 21) = 8.75; p < 0.001), and heart rate at end exercise (%predicted; F(3, 21) = 3.83; p = 0.025) compared with the 2 conditions where placebo was received. However, no statistically significant mean differences were found from the condition where subjects were told that they were consuming placebo but consuming caffeine. This suggests that a person's expectancy and potential somatic response may serve as a cue for how an ergogenic aid or placebo could affect subsequent performance.
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Affiliation(s)
- Christina A Ambrozy
- Physical Therapy Program, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan; and
- Integrative Physiology of Exercise Laboratory, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan
| | - Nicole E Hawes
- Physical Therapy Program, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan; and
- Integrative Physiology of Exercise Laboratory, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan
| | - Olivia L Hayden
- Physical Therapy Program, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan; and
- Integrative Physiology of Exercise Laboratory, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan
| | - Isabella Sortz
- Physical Therapy Program, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan; and
- Integrative Physiology of Exercise Laboratory, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan
| | - Moh H Malek
- Physical Therapy Program, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan; and
- Integrative Physiology of Exercise Laboratory, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan
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Kwak M, Succi PJ, Benitez B, Bergstrom HC. Sustainability and perceptual responses during handgrip holds to failure at two fatigue thresholds. Eur J Appl Physiol 2023; 123:2563-2573. [PMID: 37330924 DOI: 10.1007/s00421-023-05248-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 05/30/2023] [Indexed: 06/20/2023]
Abstract
PURPOSE Critical force (CF) provides an estimate of the asymptote of the force-duration curve and the physical working capacity at the rating of perceived exertion (PWCRPE) estimates the highest force that can be sustained without an increase in perceived exertion. Handgrip-related musculoskeletal disorders and injuries derived from sustained or repetitive motion-induced muscle fatigue are prevalent in the industrial workforce. Thus, it is important to understand the physiological mechanisms underlying performance during handgrip specific tasks to describe individual work capacities. This study examined prolonged, isometric, handgrip exercises by comparing the relative force levels, sustainability, and perceptual responses at two fatigue thresholds, CF and PWCRPE. METHODS Ten women (26.5 ± 3.5 years) performed submaximal, isometric handgrip holds to failure (HTF) with the dominant hand at four, randomly ordered percentages (30, 40, 50, and 60%) of maximal voluntary isometric contraction (MVIC) force to determine CF and PWCRPE. Isometric handgrip HTF were performed at CF and PWCRPE. Time to task failure and RPE responses were recorded. RESULTS There were no differences in the relative forces (p = 0.381) or sustainability (p = 0.390) between CF (18.9 ± 2.5% MVIC; 10.1 ± 2.7 min) and PWCRPE (19.5 ± 7.9% MVIC; 11.6 ± 8.4 min), and the RPE increased throughout both holds at CF and PWCRPE. CONCLUSION It is possible that complex physio-psychological factors may have contributed to the fatigue-induced task failure. CF and PWCRPE may overestimate the highest force output that can be maintained for an extended period of time without fatigue or perceptions of fatigue for isometric handgrip holds.
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Affiliation(s)
- Minyoung Kwak
- Department of Kinesiology and Health Promotion, The University of Kentucky, Lexington, KY, 40536, USA.
| | - Pasquale J Succi
- Department of Kinesiology and Health Promotion, The University of Kentucky, Lexington, KY, 40536, USA
| | - Brian Benitez
- Department of Kinesiology and Health Promotion, The University of Kentucky, Lexington, KY, 40536, USA
| | - Haley C Bergstrom
- Department of Kinesiology and Health Promotion, The University of Kentucky, Lexington, KY, 40536, USA
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Elhaj HM, Imam O, Page BW, Vitale JM, Malek MH. Perceived Consumption of a High-Dose Caffeine Drink Delays Neuromuscular Fatigue. J Strength Cond Res 2022; 36:1185-1190. [PMID: 33370007 DOI: 10.1519/jsc.0000000000003932] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
ABSTRACT Elhaj, HM, Imam, O, Page, BW, Vitale, JM, and Malek, MH. Perceived consumption of a high-dose caffeine drink delays neuromuscular fatigue. J Strength Cond Res 36(5): 1185-1190, 2022-The placebo effect is a concept in which a desired outcome arises, mainly from the belief that the treatment (i.e., supplement or drug) was beneficial although no active ingredient was given. The results of studies related to the placebo effect primarily examine functional performance. What remains unanswered, however, is whether these changes in performance are associated with neuromuscular alterations in the exercised muscles. The purpose of the study, therefore, was to determine the influence of the placebo effect on the physical working capacity fatigue threshold (PWCFT) for a continuous exercise paradigm. To achieve this aim, subjects were told that they were participating in a study to determine the dosage response (low or high) of caffeine on neuromuscular fatigue when in fact no caffeine was given during the experiment. We hypothesized that the perceived consumption of the high-dose caffeine drink would result in a higher PWCFT than the perceived consumption of the low-dose caffeine drink and placebo. Secondarily, we hypothesized that the perceived consumption of the high-dose caffeine drink would result in a higher power output than the perceived consumption of the placebo. Nine healthy college-aged men (mean ± SEM: age, 25.7 ± 1.3 years; body mass, 84.4 ± 3.1 kg; and height: 1.82 ± 0.02 m) volunteered to be in the study. For each of the visits, subjects were given an 8 oz. bottle of water with dissolved crystal light. After the drink was consumed, subjects rested in the laboratory for 1 hour before performing the incremental single-leg knee-extensor ergometry. Immediately after the termination of the incremental single-leg knee-extensor ergometry, the subject was asked which caffeine dose (placebo, low, or high) they believed they consumed for that visit. There were no significant mean differences for maximal power output for the 3 perceived conditions (placebo: 62 ± 3, low-dose caffeine: 62 ± 4, and high-dose caffeine: 65 ± 3 W). When the subjects perceived consuming the high-dose caffeine drink, there were significant mean differences (all p-values < 0.01), for PWCFT, between the other conditions (mean ± SEM: placebo: 23 ± 3 W, low-dose caffeine: 26 ± 2 W, and high-dose caffeine: 42 ± 3 W). This corresponded to a significant mean difference (all p-values < 0.01) when the PWCFT was presented as a percentage of the maximal power output (mean ± SEM: placebo: 37 ± 5%, low-dose caffeine: 42 ± 3%, and high-dose caffeine: 64 ± 3%). The application of our results may indicate that the subject's expectancy, to caffeine consumption, plays a critical role in delaying the onset of neuromuscular fatigue despite not receiving any caffeine in their drinks.
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Affiliation(s)
- Hussein M Elhaj
- Physical Therapy Program; and
- Department of Health Care Sciences, Integrative Physiology of Exercise Laboratory, Wayne State University, College of Pharmacy and Health Sciences, Detroit, Michigan
| | - Osama Imam
- Physical Therapy Program; and
- Department of Health Care Sciences, Integrative Physiology of Exercise Laboratory, Wayne State University, College of Pharmacy and Health Sciences, Detroit, Michigan
| | - Brad W Page
- Physical Therapy Program; and
- Department of Health Care Sciences, Integrative Physiology of Exercise Laboratory, Wayne State University, College of Pharmacy and Health Sciences, Detroit, Michigan
| | - Joseph M Vitale
- Physical Therapy Program; and
- Department of Health Care Sciences, Integrative Physiology of Exercise Laboratory, Wayne State University, College of Pharmacy and Health Sciences, Detroit, Michigan
| | - Moh H Malek
- Physical Therapy Program; and
- Department of Health Care Sciences, Integrative Physiology of Exercise Laboratory, Wayne State University, College of Pharmacy and Health Sciences, Detroit, Michigan
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Feldpausch JE, Blok AL, Frederick EL, Coburn JW, Malek MH. The Evolution of the Physical Work Capacity at the Fatigue Threshold Test: Past, Present, and Future. J Strength Cond Res 2021; 35:3529-3536. [PMID: 34570058 DOI: 10.1519/jsc.0000000000004124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
ABSTRACT Feldpausch, JE, Blok, AL, Frederick, EL, Coburn, JW, and Malek, MH. The evolution of the physical work capacity at the fatigue threshold test: past, present, and future. J Strength Cond Res 35(12): 3529-3536, 2021-The assessment of neuromuscular fatigue using surface electromyography has evolved over the past 40 years while maintaining some of the original key features. In this mini-review article, the goal will be to briefly present a history and systems of the physical working capacity at the fatigue threshold (PWCFT). In addition, we will discuss studies that have investigated the effect of different interventions such as supplementation, exercise, and cognitive fatigue to examine what stimuli influence the PWCFT. The latter section of this mini-review will discuss future studies that may provide additional information related to the underlying physiological mechanism(s) that influences the PWCFT. We will conclude with the practical application of PWCFT in health and sports settings.
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Affiliation(s)
- Jennie E Feldpausch
- Physical Therapy Program, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan
- Integrative Physiology of Exercise Laboratory, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan; and
| | - Amanda L Blok
- Physical Therapy Program, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan
- Integrative Physiology of Exercise Laboratory, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan; and
| | - Emily L Frederick
- Physical Therapy Program, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan
- Integrative Physiology of Exercise Laboratory, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan; and
| | - Jared W Coburn
- Department of Kinesiology, California State University, Fullerton, California
| | - Moh H Malek
- Physical Therapy Program, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan
- Integrative Physiology of Exercise Laboratory, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan; and
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Wang J, Cao D, Wang J, Liu C. Action Recognition of Lower Limbs Based on Surface Electromyography Weighted Feature Method. SENSORS (BASEL, SWITZERLAND) 2021; 21:6147. [PMID: 34577352 PMCID: PMC8470121 DOI: 10.3390/s21186147] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 09/03/2021] [Accepted: 09/08/2021] [Indexed: 11/16/2022]
Abstract
To improve the recognition rate of lower limb actions based on surface electromyography (sEMG), an effective weighted feature method is proposed, and an improved genetic algorithm support vector machine (IGA-SVM) is designed in this paper. First, for the problem of high feature redundancy and low discrimination in the surface electromyography feature extraction process, the weighted feature method is proposed based on the correlation between muscles and actions. Second, to solve the problem of the genetic algorithm selection operator easily falling into a local optimum solution, the improved genetic algorithm-support vector machine is designed by championship with sorting method. Finally, the proposed method is used to recognize six types of lower limb actions designed, and the average recognition rate reaches 94.75%. Experimental results indicate that the proposed method has definite potentiality in lower limb action recognition.
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Affiliation(s)
- Jiashuai Wang
- School of Engineering, Qufu Normal University, Rizhao 276826, China; (J.W.); (J.W.)
| | - Dianguo Cao
- School of Engineering, Qufu Normal University, Rizhao 276826, China; (J.W.); (J.W.)
| | - Jinqiang Wang
- School of Engineering, Qufu Normal University, Rizhao 276826, China; (J.W.); (J.W.)
| | - Chengyu Liu
- School of Instrument Science and Engineering, Southeast University, Nanjing 210096, China;
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Bergstrom HC, Dinyer TK, Succi PJ, Voskuil CC, Housh TJ. Applications of the Critical Power Model to Dynamic Constant External Resistance Exercise: A Brief Review of the Critical Load Test. Sports (Basel) 2021; 9:sports9020015. [PMID: 33494200 PMCID: PMC7909812 DOI: 10.3390/sports9020015] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/06/2021] [Accepted: 01/18/2021] [Indexed: 11/16/2022] Open
Abstract
The study and application of the critical power (CP) concept has spanned many decades. The CP test provides estimates of two distinct parameters, CP and W', that describe aerobic and anaerobic metabolic capacities, respectively. Various mathematical models have been used to estimate the CP and W' parameters across exercise modalities. Recently, the CP model has been applied to dynamic constant external resistance (DCER) exercises. The same hyperbolic relationship that has been established across various continuous, whole-body, dynamic movements has also been demonstrated for upper-, lower-, and whole-body DCER exercises. The asymptote of the load versus repetition relationship is defined as the critical load (CL) and the curvature constant is L'. The CL and L' can be estimated from the same linear and non-linear mathematical models used to derive the CP. The aims of this review are to (1) provide an overview of the CP concept across continuous, dynamic exercise modalities; (2) describe the recent applications of the model to DCER exercise; (3) demonstrate how the mathematical modeling of DCER exercise can be applied to further our understanding of fatigue and individual performance capabilities; and (4) make initial recommendations regarding the methodology for estimating the parameters of the CL test.
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Affiliation(s)
- Haley C. Bergstrom
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY 40506, USA; (T.K.D.); (P.J.S.); (C.C.V.)
- Correspondence:
| | - Taylor K. Dinyer
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY 40506, USA; (T.K.D.); (P.J.S.); (C.C.V.)
| | - Pasquale J. Succi
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY 40506, USA; (T.K.D.); (P.J.S.); (C.C.V.)
| | - Caleb C. Voskuil
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY 40506, USA; (T.K.D.); (P.J.S.); (C.C.V.)
| | - Terry J. Housh
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583, USA;
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Drouin PJ, Kohoko ZIN, Mew OK, Lynn MJT, Fenuta AM, Tschakovsky ME. Fatigue-independent alterations in muscle activation and effort perception during forearm exercise: role of local oxygen delivery. J Appl Physiol (1985) 2019; 127:111-121. [PMID: 31070953 DOI: 10.1152/japplphysiol.00122.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The oxygen-conforming response (OCR) of skeletal muscle refers to a downregulation of muscle force for a given muscle activation when oxygen delivery (O2D) is reduced, which is rapidly reversed when O2D is restored. We tested the hypothesis that the OCR exists in voluntary human exercise and results in compensatory changes in muscle activation to maintain force output, thereby altering perception of effort. In eight men and eight women, electromyography (EMG), oxyhemoglobin (O2Hb) and deoxyhemoglobin (HHb), forearm blood flow (FBF), and task effort awareness (TEA) were measured. Participants completed two nonfatiguing rhythmic handgrip tests consisting of 5-min steady state (SS) followed by two bouts of 2-min brachial artery compression to reduce FBF by ~50% of SS (C1 and C2), separated by 2 min of no compression (NC1) and ending with 2 min of no compression (NC2). When FBF was compromised during C1, EMG/Force (1.58 ± 0.39) increased compared with SS (1.31 ± 0.33, P = 0.001). However, EMG/Force was not restored upon FBF restoration at NC1 (1.48 ± 0.38, P = 0.479), consistent with C1 evoking skeletal muscle fatigue. When FBF was compromised during C2, EMG/Force increased (1.73 ± 0.50) compared with NC1 (1.48 ± 0.38, P = 0.013). EMG/Force returned to NC1 levels during NC2 (1.50 ± 0.39, P = 0.016), consistent with an OCR in C2. TEA (SS 2.2 ± 2.3, C1 3.9 ± 2.5, NC1 3.4 ± 2.7, C2 4.6 ± 2.7, NC2 3.9 ± 2.8) mirrored changes in EMG. It is noteworthy that during the second compromise and then restoration of muscle oxygenation EMG and TEA were rapidly restored to precompromise levels. We interpreted these findings to support the existence of an OCR and its ability to rapidly modify perception of effort during voluntary exercise. NEW & NOTEWORTHY In healthy individuals, when force output is maintained during rhythmic handgrip exercise, muscle activation and perception of effort rapidly increase with compromised muscle oxygen delivery (O2D) and then return to precompromised levels when muscle O2D is restored. These findings suggest that an oxygen-conforming response (OCR) exists and is able to modify perception of effort during voluntary exercise. Therefore, similar to fatigue, an OCR may have implications for exercise tolerance.
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Affiliation(s)
- P J Drouin
- School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada
| | - Z I N Kohoko
- School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada
| | - O K Mew
- School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada
| | - M J T Lynn
- School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada
| | - A M Fenuta
- School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada
| | - M E Tschakovsky
- School of Kinesiology and Health Studies, Queen's University , Kingston, Ontario , Canada
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Husmann F, Bruhn S, Mittlmeier T, Zschorlich V, Behrens M. Dietary Nitrate Supplementation Improves Exercise Tolerance by Reducing Muscle Fatigue and Perceptual Responses. Front Physiol 2019; 10:404. [PMID: 31068827 PMCID: PMC6491676 DOI: 10.3389/fphys.2019.00404] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 03/22/2019] [Indexed: 12/27/2022] Open
Abstract
The present study was designed to provide further insight into the mechanistic basis for the improved exercise tolerance following dietary nitrate supplementation. In a randomized, double-blind, crossover design, twelve recreationally active males completed a dynamic time-to-exhaustion test of the knee extensors after 5 days of consuming both nitrate-rich (NITRATE) and nitrate-depleted beetroot juice (PLACEBO). Participants who improved their time-to-exhaustion following NITRATE performed a time-matched trial corresponding to the PLACEBO exercise duration with another 5 days of dietary nitrate supplementation. This procedure was performed to obtain time-matched exercise trials with (NITRATEtm) and without dietary nitrate supplementation (PLACEBO). Neuromuscular tests were performed before and after each time-matched condition. Muscle fatigue was quantified as percentage change in maximal voluntary torque from pre- to post-exercise (ΔMVT). Changes in voluntary activation (ΔVA) and quadriceps twitch torque (ΔPS100) were used to quantify central and peripheral factors of muscle fatigue, respectively. Muscle oxygen saturation, quadriceps muscle activity as well as perceptual data (i.e., perception of effort and leg muscle pain) were recorded during exercise. Time-to-exhaustion was improved with NITRATE (12:41 ± 07:18 min) compared to PLACEBO (09:03 ± 04:18 min; P = 0.010). NITRATEtm resulted in both lower ΔMVT and ΔPS100 compared to PLACEBO (P = 0.002; P = 0.001, respectively). ΔVA was not different between conditions (P = 0.308). NITRATEtm resulted in reduced perception of effort and leg muscle pain. Our findings extend the mechanistic basis for the improved exercise tolerance by showing that dietary nitrate supplementation (i) attenuated the development of muscle fatigue by reducing the exercise-induced impairments in contractile muscle function; and (ii) lowered the perception of both effort and leg muscle pain during exercise.
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Affiliation(s)
- Florian Husmann
- Institute of Sport Science, University of Rostock, Rostock, Germany
| | - Sven Bruhn
- Institute of Sport Science, University of Rostock, Rostock, Germany
| | - Thomas Mittlmeier
- Department of Traumatology, Hand and Reconstructive Surgery, University Medicine Rostock, Rostock, Germany
| | | | - Martin Behrens
- Institute of Sport Science, University of Rostock, Rostock, Germany
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La Monica MB, Fukuda DH, Starling-Smith TM, Clark NW, Morales J, Hoffman JR, Stout JR. Examining work-to-rest ratios to optimize upper body sprint interval training. Respir Physiol Neurobiol 2019; 262:12-19. [PMID: 30660860 DOI: 10.1016/j.resp.2019.01.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 01/09/2019] [Accepted: 01/10/2019] [Indexed: 01/26/2023]
Abstract
The objective was to compare the metabolic influence of varying work-to-rest ratios during upper body sprint interval training (SIT). Forty-two recreationally-trained men were randomized into a training group [10 s work - 2 min of rest (10:2) or 4 min of rest (10:4), or 30 s work - 4 min of rest (30:4)] or a control group (CON). Participants underwent six training sessions over two weeks. Assessments consisted of a graded exercise test [maximal oxygen consumption (VO2peak) and peak power output (PPO)], four constant-work rate trials [critical power, anaerobic working capacity, and electromyographic fatigue threshold], and an upper body Wingate test (mean/peak power and total work). Post-training absolute and relative VO2peak was greater than pre-training for 30:4 (p = .005 and p = .009, respectively), but lower for CON (p = .001 and p = .006, respectively). Post-training PPO was greater in 30:4 (p < .001). No differences were observed during the constant-work rate trials or Wingate test. Traditional SIT appears to have enhanced VO2peak in the upper body over a short-term two-week intervention.
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Affiliation(s)
- Michael B La Monica
- Department of Kinesiology, Missouri State University, 901 S National Ave, Springfield, MO 65897, USA.
| | - David H Fukuda
- School of Kinesiology and Physical Therapy, University of Central Florida, 4000 Central Florida Blvd, Orlando, FL 32816, USA
| | - Tristan M Starling-Smith
- School of Kinesiology and Physical Therapy, University of Central Florida, 4000 Central Florida Blvd, Orlando, FL 32816, USA
| | - Nicolas W Clark
- School of Kinesiology and Physical Therapy, University of Central Florida, 4000 Central Florida Blvd, Orlando, FL 32816, USA
| | - Jose Morales
- Facultat de Ciències de l'Esport Blanquerna, Universitat Ramon Llull, C/ Císter, 34 08022 Barcelona, Spain
| | - Jay R Hoffman
- School of Kinesiology and Physical Therapy, University of Central Florida, 4000 Central Florida Blvd, Orlando, FL 32816, USA
| | - Jeffrey R Stout
- School of Kinesiology and Physical Therapy, University of Central Florida, 4000 Central Florida Blvd, Orlando, FL 32816, USA
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10
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EMG amplitude, fatigue threshold, and time to task failure: A meta-analysis. J Sci Med Sport 2018; 21:736-741. [DOI: 10.1016/j.jsams.2017.11.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 10/02/2017] [Accepted: 11/05/2017] [Indexed: 11/23/2022]
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11
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Khan FL, Lawal JM, Kapture DO, Swingle JD, Malek MH. Revisiting the Single-Visit Protocol for Determining the Electromyographic Fatigue Threshold. J Strength Cond Res 2017; 31:3503-3507. [PMID: 29016480 DOI: 10.1519/jsc.0000000000002274] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Khan, FL, Lawal, JM, Kapture, DO, Swingle, JD, and Malek, MH. Revisiting the single-visit protocol for determining the electromyographic fatigue threshold. J Strength Cond Res 31(12): 3503-3507, 2017-The electromyographic fatigue threshold (EMGFT) has been shown to demarcate between nonfatiguing and fatiguing exercise workloads. One potential limitation of incorporating the single EMGFT test in a clinical setting is the 2-minute stage increment inherit to the protocol. In most rehabilitation clinics, time with the client is limited, and any testing procedure needs to consider this factor. The purpose of this study, therefore, was to determine whether or not the estimation of the EMGFT is influenced by reducing the incremental stage to 1-minute intervals. We hypothesized that the 1-minute incremental protocol would provide similar estimates of the EMGFT as the traditional 2-minute incremental protocol. Nine college-aged men performed the single-leg knee-extensor ergometry at 1-minute (3 W) and 2-minute (6 W) stages in random order separated by 7 days. The exercise indices and the EMGFT were determined from the 2 protocols and analyzed using a paired samples t test. The EMG amplitude was assessed from the rectus femoris muscle. The results indicated significant differences between protocols for maximal power output (1 minute: 31.7 ± 2.2 W vs. 2 minutes: 38.0 ± 3.3 W, p = 0.016) and heart rate at end exercise (1 minute: 137 ± 5 b·min vs. 2 minutes: 148 ± 5 b·min, p = 0.024). There were, however, no significant mean differences for the EMGFT (1 minute: 19.8 ± 1.8 vs. 2 minutes: 20.3 ± 1.9 W, p = 0.63) and rating of perceived exertion (RPE) for the exercised leg (1 minute: 9 ± 0 vs. 2 minutes: 9 ± 1, p = 0.68). These results indicate that reducing the exercise protocol by 50% did not change the estimated EMGFT. The practical application of this finding resides in the potential use in sports or rehabilitative settings in which there is limited time with the client and no objective measures to determine neuromuscular fatigue for aerobic exercise.
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Affiliation(s)
- Fatin L Khan
- Physical Therapy Program, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan.,Integrative Physiology of Exercise Laboratory, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan
| | - Jordan M Lawal
- Physical Therapy Program, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan.,Integrative Physiology of Exercise Laboratory, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan
| | - Drew O Kapture
- Physical Therapy Program, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan.,Integrative Physiology of Exercise Laboratory, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan
| | - Joseph D Swingle
- Physical Therapy Program, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan.,Integrative Physiology of Exercise Laboratory, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan
| | - Moh H Malek
- Physical Therapy Program, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan.,Integrative Physiology of Exercise Laboratory, Department of Health Care Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan
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12
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Weakley JJS, Till K, Read DB, Roe GAB, Darrall-Jones J, Phibbs PJ, Jones B. The effects of traditional, superset, and tri-set resistance training structures on perceived intensity and physiological responses. Eur J Appl Physiol 2017; 117:1877-1889. [PMID: 28698987 PMCID: PMC5556132 DOI: 10.1007/s00421-017-3680-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 07/05/2017] [Indexed: 12/31/2022]
Abstract
Purpose Investigate the acute and short-term (i.e., 24 h) effects of traditional (TRAD), superset (SS), and tri-set (TRI) resistance training protocols on perceptions of intensity and physiological responses. Methods Fourteen male participants completed a familiarisation session and three resistance training protocols (i.e., TRAD, SS, and TRI) in a randomised-crossover design. Rating of perceived exertion, lactate concentration ([Lac]), creatine kinase concentration ([CK]), countermovement jump (CMJ), testosterone, and cortisol concentrations was measured pre, immediately, and 24-h post the resistance training sessions with magnitude-based inferences assessing changes/differences within/between protocols. Results TRI reported possible to almost certainly greater efficiency and rate of perceived exertion, although session perceived load was very likely lower. SS and TRI had very likely to almost certainly greater lactate responses during the protocols, with changes in [CK] being very likely and likely increased at 24 h, respectively. At 24-h post-training, CMJ variables in the TRAD protocol had returned to baseline; however, SS and TRI were still possibly to likely reduced. Possible increases in testosterone immediately post SS and TRI protocols were reported, with SS showing possible increases at 24-h post-training. TRAD and SS showed almost certain and likely decreases in cortisol immediately post, respectively, with TRAD reporting likely decreases at 24-h post-training. Conclusions SS and TRI can enhance training efficiency and reduce training time. However, acute and short-term physiological responses differ between protocols. Athletes can utilise SS and TRI resistance training, but may require additional recovery post-training to minimise effects of fatigue.
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Affiliation(s)
- Jonathon J S Weakley
- Room G03, Macaulay Hall, Institute for Sport, Physical Activity and Leisure, Centre for Sports Performance, Headingley Campus, Leeds Beckett University, West Yorkshire, LS6 3GZ, UK. .,Yorkshire Carnegie Rugby Union Club, Kirkstall Training Ground, Leeds Rugby Academy, Leeds, West Yorkshire, UK.
| | - Kevin Till
- Room G03, Macaulay Hall, Institute for Sport, Physical Activity and Leisure, Centre for Sports Performance, Headingley Campus, Leeds Beckett University, West Yorkshire, LS6 3GZ, UK.,Yorkshire Carnegie Rugby Union Club, Kirkstall Training Ground, Leeds Rugby Academy, Leeds, West Yorkshire, UK
| | - Dale B Read
- Room G03, Macaulay Hall, Institute for Sport, Physical Activity and Leisure, Centre for Sports Performance, Headingley Campus, Leeds Beckett University, West Yorkshire, LS6 3GZ, UK.,Yorkshire Carnegie Rugby Union Club, Kirkstall Training Ground, Leeds Rugby Academy, Leeds, West Yorkshire, UK
| | - Gregory A B Roe
- Room G03, Macaulay Hall, Institute for Sport, Physical Activity and Leisure, Centre for Sports Performance, Headingley Campus, Leeds Beckett University, West Yorkshire, LS6 3GZ, UK.,Yorkshire Carnegie Rugby Union Club, Kirkstall Training Ground, Leeds Rugby Academy, Leeds, West Yorkshire, UK
| | - Joshua Darrall-Jones
- Room G03, Macaulay Hall, Institute for Sport, Physical Activity and Leisure, Centre for Sports Performance, Headingley Campus, Leeds Beckett University, West Yorkshire, LS6 3GZ, UK.,Yorkshire Carnegie Rugby Union Club, Kirkstall Training Ground, Leeds Rugby Academy, Leeds, West Yorkshire, UK
| | - Padraic J Phibbs
- Room G03, Macaulay Hall, Institute for Sport, Physical Activity and Leisure, Centre for Sports Performance, Headingley Campus, Leeds Beckett University, West Yorkshire, LS6 3GZ, UK.,Yorkshire Carnegie Rugby Union Club, Kirkstall Training Ground, Leeds Rugby Academy, Leeds, West Yorkshire, UK
| | - Ben Jones
- Room G03, Macaulay Hall, Institute for Sport, Physical Activity and Leisure, Centre for Sports Performance, Headingley Campus, Leeds Beckett University, West Yorkshire, LS6 3GZ, UK.,Yorkshire Carnegie Rugby Union Club, Kirkstall Training Ground, Leeds Rugby Academy, Leeds, West Yorkshire, UK.,The Rugby Football League, Leeds, West Yorkshire, UK
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13
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Miramonti AA, Stout JR, Fukuda DH, Robinson EH, Wang R, La Monica MB, Hoffman JR. Effects of 4 Weeks of High-Intensity Interval Training and β-Hydroxy-β-Methylbutyric Free Acid Supplementation on the Onset of Neuromuscular Fatigue. J Strength Cond Res 2016; 30:626-34. [PMID: 26418369 DOI: 10.1519/jsc.0000000000001140] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This study investigated the effects of high-intensity interval training (HIIT) and β-hydroxy-β-methylbutyric free acid (HMB) supplementation on physical working capacity at the onset of neuromuscular fatigue threshold (PWC(FT)). Thirty-seven participants (22 men, 15 women; 22.8 ± 3.4 years) completed an incremental cycle ergometer test (graded exercise test [GXT]); electromyographic amplitude from the right vastus lateralis was recorded. Assessments occurred preceding (PRE) and after 4 weeks of supplementation (POST). Participants were randomly assigned to control (C, n = 9), placebo (P, n = 14), or supplementation (S, n = 14) groups. Both P and S completed 12 HIIT sessions, whereas C maintained normal diet and activity patterns. The PWC(FT) (W) was determined using the maximal perpendicular distance (D(MAX)) method. Electromyographic amplitude (μVrms) over time was used to generate a cubic regression. Onset of fatigue (TF) was the x-value of the point on the regression that was at D(MAX) from a line between the first and last data points. The PWC(FT) was estimated using TF and GXT power-output increments. The 2-way analysis of variance (ANOVA) (group × time) resulted in a significant interaction for PWC(FT) (F = 6.69, p = 0.004). Post hoc analysis with 1-way ANOVA resulted in no difference in PWC(FT) among groups at PRE (F = 0.87, p = 0.43); however, a difference in PWC(FT) was shown for POST (F = 5.46, p = 0.009). Post hoc analysis among POST values revealed significant differences between S and both P (p = 0.034) and C (p = 0.003). No differences (p = 0.226) were noted between P and C. Paired samples t-tests detected significant changes after HIIT for S (p < 0.001) and P (p = 0.016), but no change in C (p = 0.473). High-intensity interval training increased PWC(FT), but HMB with HIIT was more effective than HIIT alone. Furthermore, it seems that adding HMB supplementation with HIIT in untrained men and women may further improve endurance performance measures.
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Affiliation(s)
- Amelia A Miramonti
- Institute of Exercise Physiology and Wellness, Educational and Human Sciences, University of Central Florida, Orlando, Florida
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14
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Detecting fatigue thresholds from electromyographic signals: A systematic review on approaches and methodologies. J Electromyogr Kinesiol 2016; 30:216-30. [PMID: 27529668 DOI: 10.1016/j.jelekin.2016.08.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 07/26/2016] [Accepted: 08/01/2016] [Indexed: 11/23/2022] Open
Abstract
The aim of the current paper was to systematically review the relevant existing electromyographic threshold concepts within the literature. The electronic databases MEDLINE and SCOPUS were screened for papers published between January 1980 and April 2015 including the keywords: neuromuscular fatigue threshold, anaerobic threshold, electromyographic threshold, muscular fatigue, aerobic-anaerobictransition, ventilatory threshold, exercise testing, and cycle-ergometer. 32 articles were assessed with regard to their electromyographic methodologies, description of results, statistical analysis and test protocols. Only one article was of very good quality. 21 were of good quality and two articles were of very low quality. The review process revealed that: (i) there is consistent evidence of one or two non-linear increases of EMG that might reflect the additional recruitment of motor units (MU) or different fiber types during fatiguing cycle ergometer exercise, (ii) most studies reported no statistically significant difference between electromyographic and metabolic thresholds, (iii) one minute protocols with increments between 10 and 25W appear most appropriate to detect muscular threshold, (iv) threshold detection from the vastus medialis, vastus lateralis, and rectus femoris is recommended, and (v) there is a great variety in study protocols, measurement techniques, and data processing. Therefore, we recommend further research and standardization in the detection of EMGTs.
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15
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Riffe JJ, Stout JR, Fukuda DH, Robinson EH, Miramonti AA, Beyer KS, Wang R, Church DD, Muddle TWD, Hoffman JR. The Dmax method is a valid procedure to estimate physical working capacity at fatigue threshold. Muscle Nerve 2016; 55:344-349. [PMID: 27422091 DOI: 10.1002/mus.25255] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Revised: 07/06/2016] [Accepted: 07/12/2016] [Indexed: 11/09/2022]
Abstract
INTRODUCTION The purpose of this study was to determine the validity of the maximal distance-electromyography (Dmax-EMG) method for estimating physical working capacity at fatigue threshold (PWCFT ). METHODS Twenty-one men and women (age 22.9 ± 3.0 years) volunteered to perform 12 sessions of high-intensity interval training (HIIT) over 4 weeks. Before and after HIIT training, a graded exercise test (GXT) was used to estimate PWCFT using the Dmax method and the original (ORG) method. RESULTS There was a significant increase in PWCFT for both ORG (+10.6%) and Dmax (+12.1%) methods, but no significant difference in the change values between methods. Further, Bland-Altman analyses resulted in non-significant biases (ORG-Dmax) between methods at pre-HIIT (-6.4 ± 32.5 W; P > 0.05) and post-HIIT (-4.2 ± 33.1 W; P > 0.05). CONCLUSION The Dmax method is sensitive to training and is a valid method for estimating PWCFT in young men and women. Muscle Nerve 55: 344-349, 2017.
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Affiliation(s)
- Joshua J Riffe
- Institute of Exercise Physiology & Wellness, University of Central Florida, P.O. Box 161250, Orlando, Florida, 32816-1250, USA
| | - Jeffrey R Stout
- Institute of Exercise Physiology & Wellness, University of Central Florida, P.O. Box 161250, Orlando, Florida, 32816-1250, USA
| | - David H Fukuda
- Institute of Exercise Physiology & Wellness, University of Central Florida, P.O. Box 161250, Orlando, Florida, 32816-1250, USA
| | - Edward H Robinson
- Department of Nutrition, Health, and Human Performance, Meredith College, Raleigh, North Carolina, USA
| | - Amelia A Miramonti
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska, USA
| | - Kyle S Beyer
- Institute of Exercise Physiology & Wellness, University of Central Florida, P.O. Box 161250, Orlando, Florida, 32816-1250, USA
| | - Ran Wang
- Institute of Exercise Physiology & Wellness, University of Central Florida, P.O. Box 161250, Orlando, Florida, 32816-1250, USA
| | - David D Church
- Institute of Exercise Physiology & Wellness, University of Central Florida, P.O. Box 161250, Orlando, Florida, 32816-1250, USA
| | - Tyler W D Muddle
- Institute of Exercise Physiology & Wellness, University of Central Florida, P.O. Box 161250, Orlando, Florida, 32816-1250, USA
| | - Jay R Hoffman
- Institute of Exercise Physiology & Wellness, University of Central Florida, P.O. Box 161250, Orlando, Florida, 32816-1250, USA
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16
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MahmutoviĆ S, Sprout EY, Fontaine JC, Buskirk TM, Galen SS, Malek MH. Test-retest reliability of the electromyographic fatigue threshold for cycle ergometry. Muscle Nerve 2016; 53:803-7. [DOI: 10.1002/mus.24915] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 09/13/2015] [Accepted: 09/16/2015] [Indexed: 11/08/2022]
Affiliation(s)
- Selim MahmutoviĆ
- Integrative Physiology of Exercise Laboratory
- Physical Therapy Program, Eugene Applebaum College of Pharmacy and Health Sciences, Department of Health Care Sciences, Wayne State University; Detroit Michigan USA
| | - Erick Y. Sprout
- Integrative Physiology of Exercise Laboratory
- Physical Therapy Program, Eugene Applebaum College of Pharmacy and Health Sciences, Department of Health Care Sciences, Wayne State University; Detroit Michigan USA
| | - John C. Fontaine
- Integrative Physiology of Exercise Laboratory
- Physical Therapy Program, Eugene Applebaum College of Pharmacy and Health Sciences, Department of Health Care Sciences, Wayne State University; Detroit Michigan USA
| | - Travis M. Buskirk
- Integrative Physiology of Exercise Laboratory
- Physical Therapy Program, Eugene Applebaum College of Pharmacy and Health Sciences, Department of Health Care Sciences, Wayne State University; Detroit Michigan USA
| | - Sujay S. Galen
- Physical Therapy Program, Eugene Applebaum College of Pharmacy and Health Sciences, Department of Health Care Sciences, Wayne State University; Detroit Michigan USA
| | - Moh H. Malek
- Integrative Physiology of Exercise Laboratory
- Physical Therapy Program, Eugene Applebaum College of Pharmacy and Health Sciences, Department of Health Care Sciences, Wayne State University; Detroit Michigan USA
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17
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Duff TM, Fournier H, Hopp OB, Ochshorn E, Sanders ES, Stevens RE, Malek MH. Influence of Pedaling Cadence and Incremental Protocol on the Estimation of EMGFT. J Strength Cond Res 2015; 30:2206-11. [PMID: 26677833 DOI: 10.1519/jsc.0000000000001306] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Duff, TM, Fournier, H, Hopp, OB, Ochshorn, E, Sanders, ES, Stevens, RE, and Malek, MH. Influence of pedaling cadence and incremental protocol on the estimation of EMGFT. J Strength Cond Res 30(8): 2206-2211, 2016-Theoretically, the electromyographic fatigue threshold (EMGFT) is the highest exercise intensity that an individual can exercise at indefinitely without an increase in electromyography (EMG) amplitude. This index is estimated from a single incremental test. There are, however, factors that may influence EMG amplitude such as pedaling cadence or the incremental protocol used. The purposes of this study were to determine whether different pedaling cadences and/or incremental protocols influence the estimation of the EMGFT. Eight healthy college-aged men performed incremental cycle ergometry on three separate visits. The participants exercised using the following combinations of pedaling cadences and incremental protocols in random order: 25 W at 70 RPM; 13 W at 70 RPM; and 25 W at 100 RPM. The EMGFT value was determined from the vastus lateralis muscle of each participant for each of the three conditions. Separate 1-way repeated measures analysis of variances were performed to determine mean differences for various outcome indices. The mean maximal power output for the 13 W at 70 RPM condition was significantly lower than the two other conditions. There were, however, no significant mean differences (F (2,14) = 2.03; p = 0.169) for EMGFT between the three conditions. The findings of this study indicated that different pedaling cadences and incremental protocols did not influence the estimation of the EMGFT.
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Affiliation(s)
- Timothy M Duff
- 1Physical Therapy Program, Wayne State University, College of Pharmacy and Health Sciences, Department of Health Care Sciences, Detroit, Michigan; and 2Integrative Physiology of Exercise Laboratory, Wayne State University, College of Pharmacy and Health Sciences, Department of Health Care Sciences, Detroit, Michigan
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18
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Galen SS, Guffey DR, Coburn JW, Malek MH. Determining The Electromyographic Fatigue Threshold Following a Single Visit Exercise Test. J Vis Exp 2015:e52729. [PMID: 26274384 DOI: 10.3791/52729] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Theoretically, the electromyographic (EMG) fatigue threshold is the exercise intensity an individual can maintain indefinitely without the need to recruit more motor units which is associated with an increase in the EMG amplitude. Although different protocols have been used to estimate the EMG fatigue threshold they require multiple visits which are impractical for a clinical setting. Here, we present a protocol for estimating the EMG fatigue threshold for cycle ergometry which requires a single visit. This protocol is simple, convenient, and completed within 15-20 min, therefore, has the potential to be translated into a tool that clinicians can use in exercise prescription.
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Affiliation(s)
- Sujay S Galen
- Physical Therapy Program and Integrative Physiology of Exercise Laboratory, Department of Health Care Sciences, Wayne State University
| | - Darren R Guffey
- Sports Medicine and Physical Therapy, MEDSPORT, University of Michigan Health System
| | - Jared W Coburn
- Department of Kinesiology, California State University, Fullerton
| | - Moh H Malek
- Physical Therapy Program and Integrative Physiology of Exercise Laboratory, Department of Health Care Sciences, Wayne State University;
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19
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Crozara LF, Castro A, De Almeida Neto AF, Laroche DP, Cardozo AC, Gonçalves M. Utility of electromyographic fatigue threshold during treadmill running. Muscle Nerve 2015; 52:1030-9. [PMID: 25787858 DOI: 10.1002/mus.24658] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 03/03/2015] [Accepted: 03/11/2015] [Indexed: 11/06/2022]
Abstract
INTRODUCTION We investigated 2 different methods for determining muscle fatigue threshold by electromyography (EMG). METHODS Thirteen subjects completed an incremental treadmill running protocol for EMG fatigue threshold (EMGFT ) determination based on the critical power concept (EMGFT 1) and the breakpoint in the linear relationship between EMG amplitude and exercise intensity (EMGFT 2). Then, both the EMGFT 1 and EMGFT 2 were tested in a continuous treadmill running protocol. EMG was recorded from the rectus femoris (RF), vastus lateralis (VL), biceps femoris (BF), and lateral gastrocnemius (LG) muscles. RESULTS For BF, EMGFT 2 was higher than EMGFT 1, and EMGFT 1 for BF was lower than EMGFT 1 for LG. EMG of RF was higher at EMGFT 2 than at EMGFT 1, and LG EMG was lower at EMGFT 2. CONCLUSIONS EMGFT can be determined during a single treadmill running test, and EMGFT 1 may be the most appropriate method to estimate the muscle fatigue threshold during running.
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Affiliation(s)
- Luciano F Crozara
- Department of Physical Education, São Paulo State University, 1515, 24 A Avenue, Bela Vista, 13506-900, Rio Claro, São Paulo, Brazil
| | - Alex Castro
- Department of Physical Education, São Paulo State University, 1515, 24 A Avenue, Bela Vista, 13506-900, Rio Claro, São Paulo, Brazil
| | - Antonio F De Almeida Neto
- Department of Physical Education, São Paulo State University, 1515, 24 A Avenue, Bela Vista, 13506-900, Rio Claro, São Paulo, Brazil
| | - Dain P Laroche
- Department of Kinesiology, University of New Hampshire, Durham, New Hampshire, USA
| | - Adalgiso C Cardozo
- Department of Physical Education, São Paulo State University, 1515, 24 A Avenue, Bela Vista, 13506-900, Rio Claro, São Paulo, Brazil
| | - Mauro Gonçalves
- Department of Physical Education, São Paulo State University, 1515, 24 A Avenue, Bela Vista, 13506-900, Rio Claro, São Paulo, Brazil
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Camic CL, Kovacs AJ, Enquist EA, VanDusseldorp TA, Hill EC, Calantoni AM, Yemm AJ. An electromyographic-based test for estimating neuromuscular fatigue during incremental treadmill running. Physiol Meas 2014; 35:2401-13. [PMID: 25390736 DOI: 10.1088/0967-3334/35/12/2401] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The purposes of the present study were two fold: (1) to determine if the model used for estimating the physical working capacity at the fatigue threshold (PWCFT) from electromyographic (EMG) amplitude data during incremental cycle ergometry could be applied to treadmill running to derive a new neuromuscular fatigue threshold for running, and (2) to compare the running velocities associated with the PWCFT, ventilatory threshold (VT), and respiratory compensation point (RCP). Fifteen college-aged subjects (21.5 ± 1.3 y, 68.7 ± 10.5 kg, 175.9 ± 6.7 cm) performed an incremental treadmill test to exhaustion with bipolar surface EMG signals recorded from the vastus lateralis. There were significant (p < 0.05) mean differences in running velocities between the VT (11.3 ± 1.3 km h(-1)) and PWCFT (14.0 ± 2.3 km h(-1)), VT and RCP (14.0 ± 1.8 km h(-1)), but not the PWCFT and RCP. The findings of the present study indicated that the PWCFT model could be applied to a single continuous, incremental treadmill test to estimate the maximal running velocity that can be maintained prior to the onset of neuromuscular fatigue. In addition, these findings suggested that the PWCFT, like the RCP, may be used to differentiate the heavy from severe domains of exercise intensity.
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Affiliation(s)
- Clayton L Camic
- Human Performance Laboratory, Exercise and Sport Science, University of Wisconsin-La Crosse, La Crosse, Wisconsin 54601, USA
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21
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Galen SS, Malek MH. A Single Electromyographic Testing Point Is Valid to Monitor Neuromuscular Fatigue During Continuous Exercise. J Strength Cond Res 2014; 28:2754-9. [DOI: 10.1519/jsc.0000000000000616] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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22
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Emerson NS, Fukuda DH, Stout JR, Robinson EH, McCormack WP, Scanlon TC, Warren AM, Wells AJ, Gonzalez AM, Mangine GT, Fragala MS, Hoffman JR. Physical working capacity at fatigue threshold (PWCFT) is associated with sarcopenia-related body composition and measures of functionality in older adults. Arch Gerontol Geriatr 2014; 59:300-4. [PMID: 24856645 DOI: 10.1016/j.archger.2014.04.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 04/11/2014] [Accepted: 04/24/2014] [Indexed: 11/27/2022]
Abstract
The relationship between PWCFT and common measures used to assess sarcopenia in older adults were examined. Fifty-eight older adults [age: 71.1 ± 6.2 years; body mass index (BMI): 28.0 ± 5.4 kg/m(2)] completed the testing procedures. Sarcopenia-related body composition was measured by dual-energy X-ray absorptiometry and participants performed a discontinuous cycle ergometry test to determine PWCFT. Functionality assessments included maximal isometric grip strength (GRIP) and sit-to-stand (STS) repetitions in 30s. Muscle quality (MQ) was defined as GRIP relative to appendicular lean soft tissue (ALM), while skeletal muscle index (SMI) was defined as ALM/height(2). Pearson correlations were used to examine the relationships among dependent variables. PWCFT showed significant relationships with ALM (r=0.57), SMI (r=0.47), body fat percentage (BF%) (r=-0.50), GRIP (r=0.49), and STS (r=0.44). For follow-up analyses, study participants were categorized into low sarcopenia risk (n=31) or high sarcopenia risk (n=27) groups by SMI. Sarcopenia risk was associated with PWCFT [odds ratio (OR): 1.051, 95% confidence interval (CI): 1.016-1.087] and STS (OR: 1.305, CI: 1.060-1.607), but not GRIP (OR: 1.098, CI: 0.989-1.218). Using receiver-operator characteristic curve analysis, both PWCFT [area under the curve (AUC): 0.737, CI: 0.608-0.866, optimal cutoff: 37.5 W] and STS (AUC: 0.749, CI: 0.623-0.874, optimal cutoff: 12.5 repetitions) showed discriminative ability with regard to sarcopenia risk. The current data suggest that the neuromuscular fatigue threshold, as measured by PWCFT, is related to measures of body composition and function in older adults.
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Affiliation(s)
- Nadia S Emerson
- Institute of Exercise Physiology and Wellness, University of Central Florida, 4000 Central Florida Blvd, Orlando, FL 32816, United States
| | - David H Fukuda
- Institute of Exercise Physiology and Wellness, University of Central Florida, 4000 Central Florida Blvd, Orlando, FL 32816, United States.
| | - Jeffrey R Stout
- Institute of Exercise Physiology and Wellness, University of Central Florida, 4000 Central Florida Blvd, Orlando, FL 32816, United States
| | - Edward H Robinson
- Institute of Exercise Physiology and Wellness, University of Central Florida, 4000 Central Florida Blvd, Orlando, FL 32816, United States
| | - William P McCormack
- Institute of Exercise Physiology and Wellness, University of Central Florida, 4000 Central Florida Blvd, Orlando, FL 32816, United States
| | - Tyler C Scanlon
- Institute of Exercise Physiology and Wellness, University of Central Florida, 4000 Central Florida Blvd, Orlando, FL 32816, United States
| | - Ashlee M Warren
- University of Central Florida Health Center, P.O. Box 163333, University of Central Florida, Orlando, FL 32816, United States
| | - Adam J Wells
- Institute of Exercise Physiology and Wellness, University of Central Florida, 4000 Central Florida Blvd, Orlando, FL 32816, United States
| | - Adam M Gonzalez
- Institute of Exercise Physiology and Wellness, University of Central Florida, 4000 Central Florida Blvd, Orlando, FL 32816, United States
| | - Gerald T Mangine
- Institute of Exercise Physiology and Wellness, University of Central Florida, 4000 Central Florida Blvd, Orlando, FL 32816, United States
| | - Maren S Fragala
- Institute of Exercise Physiology and Wellness, University of Central Florida, 4000 Central Florida Blvd, Orlando, FL 32816, United States
| | - Jay R Hoffman
- Institute of Exercise Physiology and Wellness, University of Central Florida, 4000 Central Florida Blvd, Orlando, FL 32816, United States
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Fraga CHW, Bianco R, Serrão JC, Greco CC, Amadio AC, Gonçalves M. Comparação de protocolos de corrida para determinação de diferentes limiares. REV BRAS MED ESPORTE 2014. [DOI: 10.1590/1517-86922014200201483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
INTRODUÇÃO: Testes incrementais de corrida permitem a determinação de limiares metabólicos e neuromusculares. O objetivo do presente estudo foi comparar índices eletromiográficos e metabólicos entre dois protocolos incrementais de corrida com diferentes intervalos entre cada estágio de velocidade.MÉTODOS: Participaram do estudo 14 voluntários do sexo masculino. Os protocolos incrementais de corrida em esteira iniciaram em 8 km.h-1, com incremento de 1 km.h-1 a cada três minutos até a exaustão voluntária. Os dois protocolos diferiram quanto aos intervalos entre cada estágio de velocidade: 30 segundos (protocolo 1) e 120 segundos (protocolo 2). O limiar de fadiga eletromiográfico (LFEMG) foi determinado para os músculos reto femoral, bíceps femoral, tibial anterior e gastrocnêmio lateral. Para tanto, o comportamento do valor RMS foi correlacionado em função do tempo de corrida, sendo realizada regressão linear para determinação dos coeficientes de inclinação. O limiar de lactato foi identificado por meio do ponto de inflexão na curva lactato-intensidade e o limiar anaeróbio foi determinado por meio de interpolação linear. Foi aplicado um teste t de Student para dados pareados (p<0,05).RESULTADOS: Foi verificado que o protocolo 2 apresentou velocidade de LFEMGmaior do que o protocolo 1, apenas para o músculo BF (p=0,023), o que caracteriza uma resposta específica deste músculo em protocolos incrementais de corrida.CONCLUSÃO: Protocolos de corrida com intervalos de até dois minutos entre os estágios incrementais apresentaram resultados semelhantes para determinação do LFEMG da maioria dos músculos estudados e dos limiares metabólicos.
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Vasquez LM, McBride JM, Paul JA, Alley JR, Carson LT, Goodman CL. Effect of Resistance Exercise Performed to Volitional Failure on Ratings of Perceived Exertion. Percept Mot Skills 2013; 117:881-91. [DOI: 10.2466/27.29.pms.117x30z8] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The purpose of this investigation was to assess the effect of resistance exercise performed to volitional failure on ratings of perceived exertion (RPE) using power as an indication of fatigue. 12 male participants ( M age= 21.9 yr., SD = 1.3) performed one set of back squats at three different intensities (50%, 70%, and 90% of one repetition maximum) for both a pre-determined number of repetitions (3) and to volitional failure. RPE was significantly different between sets at 50%, 70%, and 90% when performed to a pre-determined number of repetitions, but not during volitional failure. A decrease in power between the first and the last repetitions in the volitional failure sets suggests that fatigue may confound the relationship between RPE and intensity.
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Affiliation(s)
- Ligia M. Vasquez
- Neuromuscular & Biomechanics Laboratory, Department of Health, Leisure & Exercise Science, Appalachian State University
| | - Jeffrey M. McBride
- Neuromuscular & Biomechanics Laboratory, Department of Health, Leisure & Exercise Science, Appalachian State University
| | - Judith A. Paul
- Neuromuscular & Biomechanics Laboratory, Department of Health, Leisure & Exercise Science, Appalachian State University
| | - Jessica R. Alley
- Neuromuscular & Biomechanics Laboratory, Department of Health, Leisure & Exercise Science, Appalachian State University
| | - Lauren T. Carson
- Neuromuscular & Biomechanics Laboratory, Department of Health, Leisure & Exercise Science, Appalachian State University
| | - Courtney L. Goodman
- Neuromuscular & Biomechanics Laboratory, Department of Health, Leisure & Exercise Science, Appalachian State University
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Bergstrom HC, Housh TJ, Cochrane KC, Jenkins NDM, Lewis RW, Traylor DA, Zuniga JM, Schmidt RJ, Johnson GO, Cramer JT. An examination of neuromuscular and metabolic fatigue thresholds. Physiol Meas 2013; 34:1253-67. [PMID: 24021781 DOI: 10.1088/0967-3334/34/10/1253] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This study examined the relationships among the physical working capacity at the fatigue threshold (PWCFT), the power outputs associated with the gas exchange threshold (PGET) and the respiratory compensation point (PRCP), and critical power (CP) to identify possible physiological mechanisms underlying the onset of neuromuscular fatigue. Ten participants (mean ± SD age: 20 ± 1 years) performed a maximal incremental cycle ergometer test to determine the PWCFT, PGET, and PRCP. CP was determined from the 3 min all-out test. The PWCFT (197 ± 55 W), PRCP (212 ± 50 W), and CP (208 ± 63 W) were significantly greater than the PGET (168 ± 40 W), but there were no significant differences among the PWCFT, PRCP, and CP. All thresholds were significantly inter-4 (r = 0.794-0.958). The 17% greater estimates for the PWCFT than PGET were likely related to differences in the physiological mechanisms that underlie these fatigue thresholds, while the non-significant difference and high correlation between the PWCFT and the PRCP suggested that hyperkalemia may underlie both thresholds. Furthermore, it is possible that the 5% lower estimate of the PWCFT than CP could more accurately reflect the demarcation of the heavy from severe exercise intensity domains.
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Affiliation(s)
- Haley C Bergstrom
- Human Performance Laboratory, Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA
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McCormack WP, Stout JR, Emerson NS, Scanlon TC, Warren AM, Wells AJ, Gonzalez AM, Mangine GT, Robinson EH, Fragala MS, Hoffman JR. Oral nutritional supplement fortified with beta-alanine improves physical working capacity in older adults: A randomized, placebo-controlled study. Exp Gerontol 2013; 48:933-9. [DOI: 10.1016/j.exger.2013.06.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 06/07/2013] [Accepted: 06/24/2013] [Indexed: 12/24/2022]
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Bergstrom HC, Housh TJ, Zuniga JM, Traylor DA, Camic CL, Lewis RW, Schmidt RJ, Johnson GO. The relationships among critical power determined from a 3-min all-out test, respiratory compensation point, gas exchange threshold, and ventilatory threshold. RESEARCH QUARTERLY FOR EXERCISE AND SPORT 2013; 84:232-238. [PMID: 23930549 DOI: 10.1080/02701367.2013.784723] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
PURPOSE Critical power (CP) from the 3-min test was compared to the power outputs associated with thresholds determined from gas exchange parameters that have been used to demarcate the exercise-intensity domains including the respiratory compensation point (RCP), gas exchange threshold (GET), and ventilatory threshold (VT). METHOD Twenty-eight participants performed an incremental-cycle ergometer test to exhaustion. The VT was determined from the relationship between the ventilatory equivalent for oxygen uptake (VE/VO2) versus VO2 and the GET was determined using the V-slope method (VCO2 vs. VO2). The RCP was identified from the VE-versus-VCO2 relationship. CP was the average power output during the last 30 s of the 3-min all-out test. Linear regression was used to determine the power outputs associated with the RCP, GET, and VT, as well as the VO2 associated with CP. Mean differences among the associated power outputs, percent VO2 peak, and percent peak power output for the GET, VT, RCP, and CP were analyzed using separate one-way repeated-measures analyses of variance. RESULTS There were no significant differences between CP (187 +/- 47W) and the power output associated with RCP (190 +/- 49W) or between the power outputs associated with GET (139 +/- 37W) and VT (145 +/- 37W). The power outputs associated with GET and VT, however, were significantly less than were those at CP and associated with RCRP. CONCLUSIONS These findings suggest CP and RCP demarcate the heavy from severe exercise-intensity domain and result from a different mechanism of fatigue than that of GET and VT, possibly hyperkalemia.
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Affiliation(s)
- Haley C Bergstrom
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, 110 Ruth Leverton Hall, Lincoln, NE 68583-0806, USA.
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Bergstrom HC, Housh TJ, Zuniga JM, Traylor DA, Lewis RW, Camic CL, Schmidt RJ, Johnson GO. Metabolic and neuromuscular responses at critical power from the 3-min all-out test. Appl Physiol Nutr Metab 2013; 38:7-13. [DOI: 10.1139/apnm-2012-0216] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The purpose of this study was to determine the specific metabolic and neuromuscular responses at critical power (CP) from the 3-min all-out test. Nine men (mean ± SD: aged 23.7 ± 3.3 years) performed an incremental test for the determination of peak oxygen consumption (V̇O2peak) and gas exchange threshold. CP was estimated for each subject from the 3-min all-out test. Oxygen consumption (V̇O2), the ventilation versus carbon dioxide production ratio (V̇E/V̇CO2 ratio), electromyographic (EMG) amplitude, and EMG mean power frequency (MPF) were examined during exhaustive rides at CP for each subject. There was no significant difference between the V̇O2 at exhaustion (40.6 ± 7.5 mL·kg−1·min−1) and V̇O2peak (42.9 ± 7.3 mL·kg−1·min−1). Furthermore, there were significant increases in EMG amplitude and the V̇E/V̇CO2 ratio during the exhaustive rides at CP. There was, however, no significant change in EMG MPF over time. Therefore, the current findings indicated that the 3-min all-out test overestimated CP and the demarcation between the heavy- and severe-intensity domains. Specifically, the V̇O2, ventilatory, and EMG amplitude responses were consistent with those observed during continuous exercise in the severe exercise intensity domain. It is likely that the ventilatory and EMG amplitude responses were associated with a common mechanism of fatigue that is different from what affects EMG MPF.
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Affiliation(s)
- Haley C. Bergstrom
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, 110 Ruth Leverton Hall, Lincoln, NE 68583-0806, USA
| | - Terry J. Housh
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, 110 Ruth Leverton Hall, Lincoln, NE 68583-0806, USA
| | - Jorge M. Zuniga
- Department of Exercise Science, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA
| | - Daniel A. Traylor
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, 110 Ruth Leverton Hall, Lincoln, NE 68583-0806, USA
| | - Robert W. Lewis
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, 110 Ruth Leverton Hall, Lincoln, NE 68583-0806, USA
| | - Clayton L. Camic
- Department of Exercise and Sport Science, University of Wisconsin-La Crosse, 142 Mitchell Hall, La Crosse, WI 54601, USA
| | - Richard J. Schmidt
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, 110 Ruth Leverton Hall, Lincoln, NE 68583-0806, USA
| | - Glen O. Johnson
- Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, 110 Ruth Leverton Hall, Lincoln, NE 68583-0806, USA
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Guffey DR, Gervasi BJ, Maes AA, Malek MH. Estimating electromyographic and heart rate fatigue thresholds from a single treadmill test. Muscle Nerve 2012; 46:577-81. [PMID: 22987700 DOI: 10.1002/mus.23345] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
INTRODUCTION The purposes of this study were to (1) develop a fatigue threshold based on electromyography (EMG) and heart rate (HR) responses for treadmill running from a single incremental test; and (2) propose a new fatigue threshold called the RV(EMGFT) and RV(HRFT). METHODS Eleven men performed incremental treadmill exercise to exhaustion on a single occasion. The RV(EMGFT) and RV(HRFT) were defined as the average of the highest velocity that resulted in a nonsignificant slope coefficient for the EMG amplitude versus time relationship and the lowest velocity that resulted in a significant positive slope coefficient. RESULTS There was a significant (P < 0.05) difference between the 2 thresholds [RV(EMGFT) = 11.7 ± 0.6 km/h and RV(HRFT) = 8.3 ± 0.8 km/h]. CONCLUSIONS The fatigue threshold for EMG amplitude and heart rate can be determined from a single incremental treadmill test, but there are differences between cardiac and neuromuscular factors of fatigue.
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Affiliation(s)
- Darren R Guffey
- Wayne State University, Eugene Applebaum College of Pharmacy & Health Sciences, 259 Mack Avenue, Room 2248, Detroit, Michigan 48201, USA
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Bergstrom HC, Housh TJ, Zuniga JM, Camic CL, Traylor DA, Schmidt RJ, Johnson GO. Estimated times to exhaustion and power outputs at the gas exchange threshold, physical working capacity at the rating of perceived exertion threshold, and respiratory compensation point. Appl Physiol Nutr Metab 2012; 37:872-9. [PMID: 22716291 DOI: 10.1139/h2012-057] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The purposes of this study were to compare the power outputs and estimated times to exhaustion (Tlim) at the gas exchange threshold (GET), physical working capacity at the rating of perceived exertion threshold (PWCRPE), and respiratory compensation point (RCP). Three male and 5 female subjects (mean ± SD: age, 22.4 ± 2.8 years) performed an incremental test to exhaustion on an electronically braked cycle ergometer to determine peak oxygen consumption rate, GET, and RCP. The PWCRPE was determined from ratings of perceived exertion data recorded during 3 continuous workbouts to exhaustion. The estimated Tlim values for each subject at GET, PWCRPE, and RCP were determined from power curve analyses (Tlim = axb). The results indicated that the PWCRPE (176 ± 55 W) was not significantly different from RCP (181 ± 54 W); however, GET (155 ± 42 W) was significantly less than PWCRPE and RCP. The estimated Tlim for the GET (26.1 ± 9.8 min) was significantly greater than PWCRPE (14.6 ± 5.6 min) and RCP (11.2 ± 3.1 min). The PWCRPE occurred at a mean power output that was 13.5% greater than the GET and, therefore, it is likely that the perception of effort is not driven by the same mechanism that underlies the GET (i.e., lactate buffering). Furthermore, the PWCRPE and RCP were not significantly different and, therefore, these thresholds may be associated with the same mechanisms of fatigue, such as increased levels of interstitial and (or) arterial [K+].
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Affiliation(s)
- Haley C. Bergstrom
- Human Performance Laboratory, University of Nebraska-Lincoln, Department of Nutrition and Health Sciences, 110 Ruth Leverton Hall, Lincoln, NE 68583-0806, USA
| | - Terry J. Housh
- Human Performance Laboratory, University of Nebraska-Lincoln, Department of Nutrition and Health Sciences, 110 Ruth Leverton Hall, Lincoln, NE 68583-0806, USA
| | - Jorge M. Zuniga
- Western New Mexico University, School of Allied Health, Kinesiology Department Office 104, PO Box Silver City, NM 88062, USA
| | - Clayton L. Camic
- University of Wisconsin-Platteville, Department of Health and Physical Education, 110 I Williams Fieldhouse, Platteville, WI 53818, USA
| | - Daniel A. Traylor
- Human Performance Laboratory, University of Nebraska-Lincoln, Department of Nutrition and Health Sciences, 110 Ruth Leverton Hall, Lincoln, NE 68583-0806, USA
| | - Richard J. Schmidt
- Human Performance Laboratory, University of Nebraska-Lincoln, Department of Nutrition and Health Sciences, 110 Ruth Leverton Hall, Lincoln, NE 68583-0806, USA
| | - Glen O. Johnson
- Human Performance Laboratory, University of Nebraska-Lincoln, Department of Nutrition and Health Sciences, 110 Ruth Leverton Hall, Lincoln, NE 68583-0806, USA
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Hendrix CR, Housh TJ, Camic CL, Zuniga JM, Johnson GO, Schmidt RJ. Comparing electromyographic and mechanomyographic frequency-based fatigue thresholds to critical torque during isometric forearm flexion. J Neurosci Methods 2010; 194:64-72. [DOI: 10.1016/j.jneumeth.2010.07.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Revised: 06/30/2010] [Accepted: 07/07/2010] [Indexed: 11/25/2022]
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Bouillard K, Guével A, Hug F. The electromyographic fatigue threshold is not a valid tool to assess muscle function. J Electromyogr Kinesiol 2010; 21:229-35. [PMID: 21087872 DOI: 10.1016/j.jelekin.2010.10.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Revised: 10/07/2010] [Accepted: 10/07/2010] [Indexed: 01/19/2023] Open
Abstract
The present study aimed at determining the electromyographic fatigue threshold (EMG(FT)) from the EMG activity level and the EMG frequency content of the First Dorsal Interosseous. Thirty-seven healthy subjects performed seven isometric index abductions at randomly ordered percentages of maximal voluntary contraction (i.e., 20%, 25%, 30%, 35%, 40%, 50% and 60%). During these bouts, surface EMG was measured using a linear electrodes array (i.e., seven EMG channels) in the First Dorsal Interosseous. For each subject the EMG(FT) was determined from both Root Mean Square (RMS) and Mean Power Frequency (MPF) values, only if the following criteria were met: (i) significant positive linear regression (P<0.05) between force and slope coefficient, (ii) an adjusted coefficient of determination for force versus slope coefficient relationship greater than 0.85, and (iii) a standard error for the EMG(FT) below 5% of MVC. The results showed the inability to determine an EMG(FT) in all of the 37 subjects from both RMS (9 out of 37 subjects) and MPF (27 out of 37 subjects). In addition, for the 12 subjects tested twice, the reproducibility of the EMG(FT) determination was weak (ICC=-0.029 and SEM=7.5% of MVC for EMG(FT) determined from MPF). The present results suggest that the EMG(FT) is not a valid tool to assess muscle function.
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Affiliation(s)
- Killian Bouillard
- University of Nantes, Laboratory «Motricité, Interactions, Performance» (EA 4334), F-44000, Nantes, France
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Politti F, Amorim CF, Calili L, de Oliveira Andrade A, Palomari ET. The use of surface electromyography for the study of auricular acupuncture. J Bodyw Mov Ther 2010; 14:219-26. [DOI: 10.1016/j.jbmt.2008.11.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2008] [Revised: 11/11/2008] [Accepted: 11/22/2008] [Indexed: 10/21/2022]
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Hendrix CR, Housh TJ, Zuniga JM, Camic CL, Mielke M, Johnson GO, Schmidt RJ. A mechanomyographic frequency-based fatigue threshold test. J Neurosci Methods 2010; 187:1-7. [PMID: 19945484 DOI: 10.1016/j.jneumeth.2009.11.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Revised: 11/18/2009] [Accepted: 11/23/2009] [Indexed: 11/17/2022]
Abstract
UNLABELLED Theoretically, the mechanomyographic (MMG) mean power frequency fatigue threshold (MMG MPF(FT)) describes the maximal isometric torque that can be maintained for an extended period of time with no change in the global firing rate of the unfused, activated motor units. PURPOSE The purposes of this study were twofold: (1) to determine if the mathematical model for estimating the electromyographic (EMG) MPF(FT) from the frequency of the EMG signal was applicable to the frequency domain of the MMG signal to estimate a new fatigue threshold called the MMG MPF(FT); and (2) to compare the mean torque levels derived from the MMG MPF(FT) test for the vastus lateralis (VL), vastus medialis (VM), and rectus femoris (RF) muscles during isometric leg extension muscle actions. METHODS Nine adults (4 men and 5 women; mean+/-S.D. age=21.6+/-1.2 years) performed three or four continuous, fatiguing, isometric muscle actions of the leg extensors at 30, 45, 60, and 75% of maximum voluntary isometric contraction (MVIC) to exhaustion. Surface MMG signals were recorded from the VL, VM, and RF muscles during each fatiguing isometric muscle action. The MMG MPF(FT) was defined as the y-intercept of the isometric torque versus slope coefficient (MMG MPF versus time) plot. RESULTS There were no significant differences among the MMG MPF(FT) values for the VL, VM, and RF (34.8+/-23.4, 32.1+/-16.1, and 31.6+/-15.2 Nm, respectively) muscles. CONCLUSION The MMG MPF(FT) test may provide a non-invasive method to examine the effects of various interventions on the global motor unit firing rate during isometric muscle actions.
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Affiliation(s)
- C Russell Hendrix
- Department of Nutrition and Health Sciences, Human Performance Laboratory, 110 Ruth Leverton Hall, University of Nebraska-Lincoln, Lincoln, NE 68583-0806, United States.
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HENDRIX CRUSSELL, HOUSH TERRYJ. RESPONSE. Med Sci Sports Exerc 2010. [DOI: 10.1249/mss.0b013e3181cc57ee] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Hug F. Is the EMG fatigue threshold a valid tool to assess muscle function? Med Sci Sports Exerc 2010; 42:629; author reply 630. [PMID: 20164698 DOI: 10.1249/mss.0b013e3181cc57db] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Culbertson JY, Kreider RB, Greenwood M, Cooke M. Effects of beta-alanine on muscle carnosine and exercise performance: a review of the current literature. Nutrients 2010; 2:75-98. [PMID: 22253993 PMCID: PMC3257613 DOI: 10.3390/nu2010075] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Accepted: 01/06/2010] [Indexed: 11/16/2022] Open
Abstract
Muscle carnosine has been reported to serve as a physiological buffer, possess antioxidant properties, influence enzyme regulation, and affect sarcoplasmic reticulum calcium regulation. Beta-alanine (β-ALA) is a non-essential amino acid. β-ALA supplementation (e.g., 2-6 grams/day) has been shown to increase carnosine concentrations in skeletal muscle by 20-80%. Several studies have reported that β-ALA supplementation can increase high-intensity intermittent exercise performance and/or training adaptations. Although the specific mechanism remains to be determined, the ergogenicity of β-ALA has been most commonly attributed to an increased muscle buffering capacity. More recently, researchers have investigated the effects of co-ingesting β-ALA with creatine monohydrate to determine whether there may be synergistic and/or additive benefits. This paper overviews the theoretical rationale and potential ergogenic value of β-ALA supplementation with or without creatine as well as provides future research recommendations.
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Affiliation(s)
- Julie Y. Culbertson
- Exercise and Sport Nutrition Laboratory, Department of Health and Kinesiology, Texas A&M University, College Station, TX 77845, USA;
- Author to whom correspondence should be addressed; Tel.: +1 (979) 458-1484
| | - Richard B. Kreider
- Exercise and Sport Nutrition Laboratory, Department of Health and Kinesiology, Texas A&M University, College Station, TX 77845, USA;
| | - Mike Greenwood
- Department of Health, Human Performance and Recreation, Baylor University, Waco, TX 73019, USA;
| | - Matthew Cooke
- Schools of Medicine & Health Movement Studies, The University of Queensland, Herston, Queensland, Australia;
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Kendall KL, Smith AE, Graef JL, Walter AA, Moon JR, Lockwood CM, Beck TW, Cramer JT, Stout JR. Validity of Electromyographic Fatigue Threshold as a Noninvasive Method for Tracking Changes in Ventilatory Threshold in College-Aged Men. J Strength Cond Res 2010; 24:109-13. [DOI: 10.1519/jsc.0b013e31819b79bc] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Camic CL, Housh TJ, Johnson GO, Hendrix CR, Zuniga JM, Mielke M, Schmidt RJ. An EMG frequency-based test for estimating the neuromuscular fatigue threshold during cycle ergometry. Eur J Appl Physiol 2009; 108:337-45. [DOI: 10.1007/s00421-009-1239-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/28/2009] [Indexed: 11/28/2022]
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Hendrix CR, Housh TJ, Johnson GO, Mielke M, Camic CL, Zuniga JM, Schmidt RJ. Comparison of critical force to EMG fatigue thresholds during isometric leg extension. Med Sci Sports Exerc 2009; 41:956-64. [PMID: 19276836 DOI: 10.1249/mss.0b013e318190bdf7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
UNLABELLED Theoretically, the critical force (CF) and the EMG fatigue threshold (EMGFT) tests demarcate fatiguing from nonfatiguing isometric torque levels. PURPOSE The purpose of this study was twofold: 1) to determine whether the mathematical model for estimating the EMGFT during cycle ergometry was applicable to isometric leg extension muscle actions and 2) to compare the mean torque level from the CF test to those of EMGFT tests for the vastus lateralis (VL), vastus medialis (VM), and rectus femoris (RF) muscles during isometric muscle actions. METHODS The slope coefficient of the linear relationship between total "isometric work" (Wlim in newton-meters per second) and time to exhaustion (Tlim in seconds) was defined as the CF. The EMGFT was defined as the y-intercept of the isometric torque versus EMG fatigue curve slope coefficient relationship. RESULTS There was a significant (P < 0.05) mean difference between the CF (25.9 +/- 12.1 N.m) and the EMGFT value for the RF (41.1 +/- 20.7 N.m) muscle. There were no significant differences, however, in EMGFT values among the three superficial muscles of the quadriceps femoris. In addition, the mean CF (17.6% maximum voluntary isometric contraction [MVIC]) occurred at a percentage of MVIC that is typically not affected by circulatory occlusion (20% MVIC), whereas the mean EMGFT values for the VL (25.9% MVIC), VM (22.9% MVIC), and RF (27.8% MVIC) exceeded this threshold.
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Affiliation(s)
- C Russell Hendrix
- Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, Lincoln, NE 68583-0806, USA.
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Hug F, Nordez A, Guével A. Can the electromyographic fatigue threshold be determined from superficial elbow flexor muscles during an isometric single-joint task? Eur J Appl Physiol 2009; 107:193-201. [PMID: 19551403 DOI: 10.1007/s00421-009-1114-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/08/2009] [Indexed: 11/28/2022]
Abstract
The purpose of this study was to compare the electromyographic fatigue threshold (EMG(FT)) values determined simultaneously from superficial elbow flexor muscles during an isometric single-joint task. Eight subjects performed isometric elbow flexions at randomly ordered percentages of maximal voluntary contraction (20, 30, 40, 50 and 60%). During these bouts, electromyographic (EMG) activity was measured in the anterior head of Deltoïd, lateral head of Triceps brachii, Brachioradialis and both short and long head of Biceps brachii. For each subject and each muscle, the EMG amplitude data were plotted as function of time for the five submaximal bouts. The slope coefficient of the EMG amplitude versus time linear relationships were plotted against force level. EMG(FT) was determined as the y-intercept of this relationship and considered as valid only if the following criteria were met: (1) significant positive linear regression (P < 0.05) between force and slope coefficient, (2) an adjusted coefficient of determination for force versus slope coefficient relationship greater than 0.85, and (3) a standard error for the EMG(FT) below 5% of maximal voluntary contraction. The EMG(FT) could only be determined for one muscle (the long head of Biceps brachii) and only in three out of the eight subjects (mean value = 24.9 +/- 1.1% of maximal voluntary contraction). The lack of EMG(FT) in most of the subjects (5/8) could be explained by putative compensations between elbow muscles which were indirectly observed in some subjects. In this way, EMG(FT) should be studied from a more simple movement i.e., ideally a movement implying mainly one muscle.
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Affiliation(s)
- François Hug
- Laboratory Motricité, Interactions, Performance (EA 4334), University of Nantes, 25 bis boulevard Guy Mollet, BP 72206, 44322, Nantes Cedex 3, France.
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Mielke M, Housh TJ, Hendrix CR, Camic CL, Zuniga JM, Schmidt RJ, Johnson GO. Oxygen uptake, heart rate, and ratings of perceived exertion at the PWCVo2. J Strength Cond Res 2009; 23:1292-9. [PMID: 19528845 DOI: 10.1519/jsc.0b013e31819b792e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The purpose of the present study was to examine the oxygen uptake (Vo2), heart rate (HR), and ratings of perceived exertion (RPE [OMNI-Leg 0-10]) responses during continuous 1-hour cycle ergometer rides at the PWCVo2 (physical working capacity at the oxygen consumption threshold). Eight subjects (mean age +/- SD = 23 +/- 3.2 years) performed a maximal test to exhaustion for the determination of Vo2peak and ventilatory threshold (VT). The subjects also performed 4 randomly ordered 8-minute workbouts at different power outputs (ranging from 84 to 245 W) to determine the PWCVo2 and a continuous 1-hour cycle ergometer ride at the PWCVo2 during which Vo2, HR, and RPE data were collected every 2 minutes. The PWCVo2 (114 +/- 39 W) and VT (133 +/- 44 W) were not significantly different and occurred at 56 and 63% Vo2peak, respectively. Linear regression showed that the slope coefficients for the Vo2, HR, and RPE vs. time relationships for the continuous 1-hour workbouts were significantly greater than zero. Furthermore, a t-test about a single mean indicated that the mean slope coefficient for the HR vs. time relationship was significantly greater than 0.1 bpm x min(-1) (the rate of increase in HR that can be maintained for an 8-hour day). The results of this study indicated that PWCVo2 could be maintained for an extended period. However, the maximal power output associated with steady state Vo2, HR, and RPE responses was overestimated. The mean increase in Vo2 during the continuous 1-hour ride was 270 mL, which suggested that the PWCVo2 may demarcate the moderate from heavy exercise domains. The mean HR slope coefficient of 0.3 bpm x min(-1) indicated that the power output at the PWCVo2 could likely be maintained for greater than 2 hours.
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Affiliation(s)
- Michelle Mielke
- Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, Lincoln, Nebraska, USA.
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Meeusen R. Commentaries on Viewpoint: Perception of effort during exercise is independent of afferent feedback from skeletal muscles, heart, and lungs. J Appl Physiol (1985) 2009; 106:2066; author reply 2067. [DOI: 10.1152/japplphysiol.00367.2009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Hendrix CR, Housh TJ, Johnson GO, Mielke M, Camic CL, Zuniga JM, Schmidt RJ. A new EMG frequency-based fatigue threshold test. J Neurosci Methods 2009; 181:45-51. [PMID: 19394361 DOI: 10.1016/j.jneumeth.2009.04.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Revised: 04/13/2009] [Accepted: 04/15/2009] [Indexed: 11/19/2022]
Abstract
UNLABELLED Theoretically, the critical torque (CT) and electromyographic mean power frequency fatigue threshold (EMG MPF(FT)) describe the maximal non-fatiguing isometric torque level. PURPOSE The purposes of this study were two-fold: (1) to determine if the mathematical model for estimating the EMG fatigue threshold (EMG(FT)) from the amplitude of the EMG signal was applicable to the frequency domain of the EMG signal to estimate a new fatigue threshold called the EMG MPF(FT); and (2) to compare the torque level derived from the CT test to that of the EMG MPF(FT) test for the vastus lateralis (VL) muscle during isometric muscle actions of the leg extensors. METHODS Nine adults (4 men and 5 women; mean+/-SD age=21.6+/-1.2 yr) performed three or four continuous, fatiguing, isometric muscle actions of the leg extensors at 30, 45, 60, and 75% of maximum voluntary isometric contraction (MVIC) to determine the time to exhaustion (T(lim)) values. The slope coefficient of the linear relationship between total isometric "work" (W(lim) in Nms=TorquexT(lim)) and T(lim) was defined as the CT. Surface EMG signals were recorded from the vastus lateralis (VL) muscle during each fatiguing isometric muscle action. The EMG MPF(FT) was defined as the y-intercept of the isometric torque versus slope coefficient (EMG MPF versus time) plot. RESULTS There were no significant differences between CT (19.7+/-5.8%MVIC) and EMG MPF(FT) (21.4+/-8.7%MVIC). CONCLUSION These findings provided indirect validation of the EMG MPF(FT) test.
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Affiliation(s)
- C Russell Hendrix
- Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, Lincoln, NE 68583-0806, USA.
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A comparison of critical force and electromyographic fatigue threshold for isometric muscle actions of the forearm flexors. Eur J Appl Physiol 2009; 105:333-42. [PMID: 19137323 DOI: 10.1007/s00421-008-0895-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/03/2008] [Indexed: 10/21/2022]
Abstract
The purpose of this study was twofold: (1) to determine if the mathematical model used for estimating the EMG(FT) during cycle ergometry was applicable to isometric muscle actions; and (2) to compare the mean torque level from the CF test to that of the EMG(FT) test. The CF was defined as the slope coefficient of the linear relationship between total "isometric work" (W (lim) in N m s) and time to exhaustion (T (lim)). The EMG(FT) was defined as the y-intercept of the isometric torque versus EMG fatigue curve slope coefficient relationship. There was a significant (p < 0.05) mean difference between CF (6.6 +/- 3.2 N m) and EMG(FT) (10.9 +/- 4.7 N m). The results of the present study suggested that, during isometric muscle actions of the forearm flexors, fatigue thresholds estimated from the W (lim) versus T (lim) relationship (CF) are different from those estimated from electromyographic fatigue curves (EMG(FT)).
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The effects of beta-alanine supplementation and high-intensity interval training on neuromuscular fatigue and muscle function. Eur J Appl Physiol 2008; 105:357-63. [DOI: 10.1007/s00421-008-0911-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/17/2008] [Indexed: 11/26/2022]
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Mielke M, Housh TJ, Malek MH, Beck TW, Hendrix CR, Schmidt RJ, Johnson GO. Estimated Times to Exhaustion at the PWC JOURNAL/jscr/04.03/00124278-200811000-00039/OV0312_6/v/2021-02-09T093608Z/r/image-png o2, PWCHRT, and VT. J Strength Cond Res 2008; 22:2003-10. [DOI: 10.1519/jsc.0b013e3181876a1c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Graef JL, Smith AE, Kendall KL, Walter AA, Moon JR, Lockwood CM, Beck TW, Cramer JT, Stout JR. The relationships among endurance performance measures as estimated from VO2PEAK, ventilatory threshold, and electromyographic fatigue threshold: a relationship design. DYNAMIC MEDICINE : DM 2008; 7:15. [PMID: 18783626 PMCID: PMC2542988 DOI: 10.1186/1476-5918-7-15] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Accepted: 09/10/2008] [Indexed: 11/21/2022]
Abstract
Background The use of surface electromyography has been accepted as a valid, non-invasive measure of neuromuscular fatigue. In particular, the electromyographic fatigue threshold test (EMGFT) is a reliable submaximal tool to identify the onset of fatigue. This study examined the metabolic relationship between VO2PEAK, ventilatory threshold (VT), and the EMGFT, as well as compared the power output at VO2PEAK, VT, and EMGFT. Methods Thirty-eight college-aged males (mean ± SD = 22.5 ± 3.5 yrs) performed an incremental test to exhaustion on an electronically-braked cycle ergometer for the determination of VO2PEAK and VT. Each subject also performed a discontinuous incremental cycle ergometer test to determine their EMGFT value, determined from bipolar surface electrodes placed on the longitudinal axis of the vastus lateralis of the right thigh. Subjects completed a total of four, 2-minute work bouts (ranging from 75–325 W). Adequate rest was given between bouts to allow for subjects' heart rate to drop within 10 beats of their resting heart rate. The EMG amplitude was averaged over 10-second intervals and plotted over the 2-minute work bout. The resulting slopes from each successive work bout were used to calculate EMGFT. Results Power outputs and VO2 values from each subject's incremental test to exhaustion were regressed. The linear equations were used to compute the VO2 value that corresponded to each fatigue threshold. Two separate one-way repeated measure ANOVAs indicated significant differences (p < 0.05) among metabolic parameters and power outputs. However, the mean metabolic values for VT (1.90 ± 0.50 l·min-1) and EMGFTVO2(1.84 ± 0.53 l·min-1) were not significantly different (p > 0.05) and were highly correlated (r = 0.750). Furthermore, the mean workload at VT was 130.7 ± 37.8 W compared with 134.1 ± 43.5 W at EMGFT (p > 0.05) with a strong correlation between the two variables (r = 0.766). Conclusion Metabolic measurements, as well as the power outputs at VT and EMGFT, were strongly correlated. The significant relationship between VT and EMGFT suggests that both procedures may reflect similar physiological factors associated with the onset of fatigue. As a result of these findings, the EMGFT test may provide an attractive alternative to estimating VT.
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Affiliation(s)
- Jennifer L Graef
- Department of Health and Exercise Science, University of Oklahoma, Huston Huffman Center, 1401 Asp Ave., Norman, OK 73019, USA
| | - Abbie E Smith
- Department of Health and Exercise Science, University of Oklahoma, Huston Huffman Center, 1401 Asp Ave., Norman, OK 73019, USA
| | - Kristina L Kendall
- Department of Health and Exercise Science, University of Oklahoma, Huston Huffman Center, 1401 Asp Ave., Norman, OK 73019, USA
| | - Ashley A Walter
- Department of Health and Exercise Science, University of Oklahoma, Huston Huffman Center, 1401 Asp Ave., Norman, OK 73019, USA
| | - Jordan R Moon
- Department of Health and Exercise Science, University of Oklahoma, Huston Huffman Center, 1401 Asp Ave., Norman, OK 73019, USA
| | - Christopher M Lockwood
- Department of Health and Exercise Science, University of Oklahoma, Huston Huffman Center, 1401 Asp Ave., Norman, OK 73019, USA
| | - Travis W Beck
- Department of Health and Exercise Science, University of Oklahoma, Huston Huffman Center, 1401 Asp Ave., Norman, OK 73019, USA
| | - Joel T Cramer
- Department of Health and Exercise Science, University of Oklahoma, Huston Huffman Center, 1401 Asp Ave., Norman, OK 73019, USA
| | - Jeffrey R Stout
- Department of Health and Exercise Science, University of Oklahoma, Huston Huffman Center, 1401 Asp Ave., Norman, OK 73019, USA
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Mielke M, Housh TJ, Malek MH, Beck TW, Schmidt RJ, Johnson GO. The Development of Rating of Perceived Exertion-Based Tests of Physical Working Capacity. J Strength Cond Res 2008; 22:293-302. [DOI: 10.1519/jsc.0b013e31815f58ca] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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