Slight power output manipulations around the maximal lactate steady state have an impact on fatigue in females and males.

2021 ◽  
Author(s):  
Rafael de Almeida Azevedo ◽  
Jonas Forot ◽  
Danilo Iannetta ◽  
Martin J. MacInnis ◽  
Guillaume Y. Millet ◽  
...  
Keyword(s):  
Steady State ◽  
Power Output ◽  
Contractile Function ◽  
Femoral Nerve ◽  
Peak Torque ◽  
Knee Extensors ◽  
Time To Exhaustion ◽  
Maximal Lactate Steady State ◽  
Subsequent Performance ◽  
Single Twitch

Neuromuscular fatigue (NMF) and exercise performance are affected by exercise intensity and sex differences. However, whether slight changes in power output (PO) below and above the maximal lactate steady-state (MLSS) impact NMF and subsequent performance (time to exhaustion, TTE) is unknown. Purpose: This study compared NMF and TTE in females and males in response to exercise performed at MLSS, 10 W below (MLSS-10) and above (MLSS+10). Methods: Twenty participants (9 females) performed three 30-min constant-PO exercise bouts followed (1 min delay) by a TTE at 80% of the peak-PO. NMF was characterized by isometric maximal voluntary contractions (IMVC) and femoral nerve electrical stimulation of knee extensors [e.g. peak torque of potentiated high-frequency (Db100) and single twitch (TwPt)] before and immediately after the constant-PO and TTE bouts. Results: IMVC declined less after MLSS-10 (-18±10%) compared to MLSS (-26±14%) and MLSS+10 (-31±11%) (all p<0.05), and the Db100 decline was greater after MLSS+10 (-24±14%) compared to the other intensities (MLSS-10: -15±9%; MLSS: -18±11%) (all p<0.05). Females showed smaller reductions in IMVC and TwPt compared to males after constant-PO bouts (all p<0.05), this difference being not dependant on intensity. TTE was negatively impacted by increasing the PO in the constant-PO (p<0.001), with no differences in end-exercise NMF (p>0.05). Conclusion: Slight changes in PO around MLSS elicited great changes in the reduction of maximal voluntary force and impairments in contractile function. Although NMF was lower in females compared to males, the changes in PO around the MLSS impacted both sexes similarly.

Exercise slightly above the maximal lactate steady state reduces self-efficacy and increases negative affect

2019 ◽  
Author(s):  
James Graeme Wrightson ◽  
Louis Passfield
Keyword(s):  
Steady State ◽  
Negative Affect ◽  
Power Output ◽  
Self Efficacy ◽  
Repeated Measures ◽  
Physiological State ◽  
Constant Load ◽  
Peak Power Output ◽  
Time To Exhaustion ◽  
Maximal Lactate Steady State

Objectives: To examine the effect of exercise at and slightly above the maximal lactate steady state (MLSS) on self-efficacy, affect and effort, and their associations with exercise tolerance.Design: Counterbalanced, repeated measures designMethod: Participants performed two 30‐minute constant‐load cycling exercise at a power output equal to that at MLSS and 10 W above MLSS, immediately followed by a time‐to‐exhaustion test at 80% of their peak power output. Self-efficacy, affect and effort were measured before and after 30 minutes of cycling at and above MLSS.Results: Negative affect and effort higher, and self-efficacy and time to exhaustion were reduced, following cycling at MLSS + 10 W compared to cycling at the MLSS. Following exercise at the MLSS self-efficacy, affect and effort were all associated with subsequent time-to exhaustion. However, following exercise at MLSS + 10 W, only affect was associated with time-to exhaustion. Conclusions: Self efficacy, affect and effort are profoundly affected by physiological state, highlighting the influence of somatic states on perceptions and emotions during exercise. The affective response to exercise appears to be associated with exercise tolerance, indicating that the emotional, as well as physiological, responses should be considered when prescribing exercise training.

scholarly journals Sex-Related Differences in the Maximal Lactate Steady State

Sports ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 154 ◽  
Author(s):  
Paul Hafen ◽  
Pat Vehrs
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Steady State ◽  
Respiratory Exchange Ratio ◽  
Time To Exhaustion ◽  
Distance Runners ◽  
Maximal Lactate Steady State ◽  
Training Tool ◽  
Significant Difference ◽  
Males And Females

The maximal lactate steady state (MLSS) is one of the factors that differentiates performance in aerobic events. The purpose of this study was to investigate the sex differences in oxygen consumption (VO2), heart rate (HR), and the respiratory exchange ratio (RER) at the MLSS in well-trained distance runners. Twenty-two (12 female, 10 male) well-trained distance runners (23 ± 5.0 years) performed multiple 30-min steady-state runs to determine their MLSS, during which blood lactate and respiratory gas exchange measures were taken. To interpret the MLSS intensity as a training tool, runners completed a time-to-exhaustion (TTE) run at their MLSS. The relative intensity at which the MLSS occurred was identical between males and females according to both oxygen consumption (83 ± 5 %O2max) and heart rate (89 ± 7 %HRmax). However, female runners displayed a significantly lower RER at MLSS compared to male runners (p < 0.0001; 0.84 ± 0.02 vs. 0.88 ± 0.04, respectively). There was not a significant difference in TTE at MLSS between males (79 ± 17 min) and females (80 ± 25 min). Due to the observed difference in the RER at the MLSS, it is suggested that RER derived estimates of MLSS be sex-specific. While the RER data suggest that the MLSS represents different metabolic intensities for males and females, the relative training load of MLSS appears to be similar in males and female runners.

Comparison of Power Outputs During Time Trialing and Power Outputs Eliciting Metabolic Variables in Cycle Ergometry

2010 ◽  
Vol 20 (2) ◽  
pp. 115-121
Author(s):  
David Michael Morris ◽  
Rebecca Susan Shafer
Keyword(s):  
Steady State ◽  
Blood Lactate ◽  
Power Output ◽  
Lactate Threshold ◽  
Time Trial ◽  
Cycle Ergometry ◽  
Moderate Altitude ◽  
Maximal Lactate Steady State ◽  
Metabolic Variables ◽  
Power Outputs

The authors sought to compare power output at blood lactate threshold, maximal lactate steady state, and pH threshold with the average power output during a simulated 20-km time trial assessed during cycle ergometry. Participants (N = 13) were trained male and female cyclists and triathletes, all permanent residents at moderate altitude (1,525–2,225 m). Testing was performed at 1,525 or 1,860 m altitude. Power outputs were determined during a simulated 20-km time trial (PTT), at blood pH threshold (PpHT), at maximal lactate steady state (PMLSS), and at blood lactate threshold determined by 2 methods: the highest power output that did not result in consecutive and continued increases in blood lactate concentrations from exercising baseline (PLT) and the highest power output that did not result in consecutive and continued increases of ≥1 mmol/L in blood lactate concentrations from exercising baseline (PLT1). PLT, PLT1, and PMLSS were all significantly lower than PpHT (p < .05) and PTT (p < .05). No significant difference was observed between PpHT and PTT (p > .05). Significant correlations were observed between each of the metabolic variables, PLT, PLT1, PMLSS, and PpHT, compared with PTT (p < .05). The authors conclude that, of the 4 metabolic variables, only PpHT offered an accurate reflection of PTT.

Time to exhaustion at intermittent maximal lactate steady state is longer than continuous cycling exercise

2012 ◽  
Vol 37 (6) ◽  
pp. 1047-1053 ◽  
Author(s):  
Talita Grossl ◽  
Ricardo Dantas de Lucas ◽  
Kristopher Mendes de Souza ◽  
Luiz Guilherme Antonacci Guglielmo
Keyword(s):  
Steady State ◽  
Endurance Training ◽  
Intermittent Exercise ◽  
Cycle Ergometer ◽  
Time To Exhaustion ◽  
Maximal Lactate Steady State ◽  
Continuous Exercise ◽  
Physiological Variables ◽  
Metabolic Variables ◽  
Work Done

The maximal lactate steady state (MLSS) represents a submaximal intensity that may be important in prescribing both continuous and interval endurance training. This study compared time to exhaustion (TTE) at MLSS in continuous and intermittent (i.e., with pauses) exercise, investigating whether physiological variables differ between these exercise modes. Fourteen trained male cyclists volunteered for this investigation and performed an incremental test, several 30-min tests to determine two MLSS intensities (continuous and discontinuous protocol), and two randomized tests until exhaustion at MLSS intensities on a cycle ergometer. The intermittent or discontinuous protocol was performed using 5 min of cycling, with an interval of 1 min of passive rest. TTE at intermittent MLSS was 24% longer than TTE at continuous exercise (67.8 ± 14.3 min vs. 54.7 ± 10.9 min; p < 0.05; effect sizes = 1.04), even though the absolute power output of intermittent MLSS was higher than continuous (268 ± 29 W vs. 251 ± 29 W; p < 0.05). Additionally, the total mechanical work done was significantly lower at continuous exercise than at intermittent exercise. Likewise, regarding cardiorespiratory and metabolic variables, we observed greater responses during intermittent exercise than during continuous exercise at MLSS. Thus, for endurance training prescription, this is an important finding to apply in extensive interval sessions at MLSS. This result suggests that interval sessions at discontinuous MLSS should be used instead of continuous MLSS, as discontinuous MLSS allows for a larger amount of total work during the exhaustion trial.

scholarly journals Caffeine Affects Time to Exhaustion and Substrate Oxidation during Cycling at Maximal Lactate Steady State

Nutrients ◽  
2015 ◽  
Vol 7 (7) ◽  
pp. 5254-5264 ◽  
Author(s):  
Rogério Cruz ◽  
Rafael de Aguiar ◽  
Tiago Turnes ◽  
Luiz Guglielmo ◽  
Ralph Beneke ◽  
...  
Keyword(s):  
Steady State ◽  
Substrate Oxidation ◽  
Time To Exhaustion ◽  
Maximal Lactate Steady State

Reliability of time-to-exhaustion and selected psycho-physiological variables during constant-load cycling at the maximal lactate steady-state

2017 ◽  
Vol 42 (2) ◽  
pp. 142-147 ◽  
Author(s):  
Oliver Faude ◽  
Anne Hecksteden ◽  
Daniel Hammes ◽  
Franck Schumacher ◽  
Eric Besenius ◽  
...  
Keyword(s):  
Steady State ◽  
Oxygen Uptake ◽  
Blood Lactate ◽  
Maximal Oxygen Uptake ◽  
Perceived Exertion ◽  
Constant Load ◽  
Time To Exhaustion ◽  
Maximal Lactate Steady State ◽  
Physiological Variables ◽  
Load Tests

The maximal lactate steady-state (MLSS) is frequently assessed for prescribing endurance exercise intensity. Knowledge of the intra-individual variability of the MLSS is important for practical application. To date, little is known about the reliability of time-to-exhaustion and physiological responses to exercise at MLSS. Twenty-one healthy men (age, 25.2 (SD 3.3) years; height, 1.83 (0.06) m; body mass, 78.9 (8.9) kg; maximal oxygen uptake, 57.1 (10.7) mL·min−1·kg−1) performed 1 incremental exercise test, and 2 constant-load tests to determine MLSS intensity. Subsequently, 2 open-end constant-load tests (MLSS 1 and 2) at MLSS intensity (3.0 (0.7) W·kg−1, 76% (10%) maximal oxygen uptake) were carried out. During the tests, blood lactate concentrations, heart rate, ratings of perceived exertion (RPE), variables of gas exchange, and core body temperature were determined. Time-to-exhaustion was 50.8 (14.0) and 48.2 (16.7) min in MLSS 1 and 2 (mean change: −2.6 (95% confidence interval: −7.8, 2.6)), respectively. The coefficient of variation (CV) was high for time-to-exhaustion (24.6%) and for mean (4.8 (1.2) mmol·L−1) and end (5.4 (1.7) mmol·L−1) blood lactate concentrations (15.7% and 19.3%). The CV of mean exercise values for all other parameters ranged from 1.4% (core temperature) to 8.3% (ventilation). At termination, the CVs ranged from 0.8% (RPE) to 11.8% (breathing frequency). The low reliability of time-to-exhaustion and blood lactate concentration at MLSS indicates that the precise individual intensity prescription may be challenging. Moreover, the obtained data may serve as reference to allow for the separation of intervention effects from random variation in our sample.

scholarly journals Characterization of performance fatigability during a self-paced exercise

2019 ◽  
Vol 127 (3) ◽  
pp. 838-846 ◽  
Author(s):  
Rafael de Almeida Azevedo ◽  
Ramon Cruz ◽  
Patrícia Couto ◽  
Marcos David Silva-Cavalcante ◽  
Daniel Boari ◽  
...  
Keyword(s):  
Time Course ◽  
Muscle Activation ◽  
Contractile Function ◽  
Time Trial ◽  
Peak Torque ◽  
Voluntary Activation ◽  
Knee Extensors ◽  
Electromyographic Activity ◽  
Cycling Time Trial ◽  
Fast Start

Pacing during a high-intensity cycling time trial (TT) appears to prevent premature task failure, but the performance fatigability during a self-paced exercise is currently unknown. Therefore, the current study characterized the time course of performance fatigability during a 4-km TT. Eleven male cyclists performed three separated TTs in a crossover, counterbalanced design. The TTs lasted until the end of the fast-start (FS; 600 ± 205 m), even-pace (EP; 3,600 ± 190 m), and end-spurt (ES; 4,000 m) phases. Performance fatigability was characterized by using isometric maximal voluntary contractions (IMVCs), whereas the muscle activation [i.e., voluntary activation (VA)] and contractile function of knee extensors [e.g., peak torque of potentiated twitches (TwPt)] were evaluated using electrically evoked contractions performed before and 1 min after each specific part of the trial. Gas exchange, power output (PO), and electromyographic activity (EMG) were also recorded. EMG/PO showed an abrupt increase followed by a continuous decrease toward the end of FS, resulting in a drop in IMVC (−12%), VA (−8%), and TwPt (−23%). EMG/PO was stable during EP, with no additional drop on IMVC, VA, or TwPt (−12%, −6%, and −22%, respectively). EMG/PO increased abruptly during the ES, but there was no change in IMVCs, VA, or TwPt (−13%, −8%, and −26%, respectively). These findings demonstrate that the performance fatigability during a self-paced exercise is characterized by a large drop in contractile function and muscle activation at the beginning of the trial (i.e., FS), without additional change during the middle and end phases (i.e., EP and ES). NEW & NOTEWORTHY The time course of performance fatigability throughout a self-paced exercise is currently unknown. The results showed that a large amount of muscle activation and contractile function impairments are attained early on a self-paced exercise (first ∼15% of the total time trial distance) and maintained throughout the test. This novel finding characterizes the performance fatigability from a contractile function and muscle activation perspective, which brings new insights for future studies focused on real-world exercise training and competition.

Accuracy of neuro-fuzzy logic and regression calculations in determining maximal lactate steady-state power output from incremental tests in humans

2002 ◽  
Vol 88 (3) ◽  
pp. 264-274 ◽  
Author(s):  
Gerhard Smekal ◽  
Arno Scharl ◽  
Serge von Duvillard ◽  
Rochus Pokan ◽  
Arnold Baca ◽  
...  
Keyword(s):  
Fuzzy Logic ◽  
Steady State ◽  
Power Output ◽  
State Power ◽  
Maximal Lactate Steady State ◽  
Neuro Fuzzy

Time to Exhaustion at Continuous and Intermittent Maximal Lactate Steady State During Running Exercise

2014 ◽  
Vol 9 (5) ◽  
pp. 772-776 ◽  
Author(s):  
Naiandra Dittrich ◽  
Ricardo Dantas de Lucas ◽  
Ralph Beneke ◽  
Luiz Guilherme Antonacci Guglielmo
Keyword(s):  
Steady State ◽  
Repeated Measures ◽  
Perceived Exertion ◽  
Intermittent Exercise ◽  
Continuous Model ◽  
Rating Of Perceived Exertion ◽  
Time To Exhaustion ◽  
Maximal Lactate Steady State ◽  
Physiological Variables ◽  
Trained Runners

The purpose of this study was to determine and compare the time to exhaustion (TE) and the physiological responses at continuous and intermittent (ratio 5:1) maximal lactate steady state (MLSS) in well-trained runners. Ten athletes (32.7 ± 6.9 y, VO2max 61.7 ± 3.9 mL · kg−1 · min−1) performed an incremental treadmill test, three to five 30-min constant-speed tests to determine the MLSS continuous and intermittent (5 min of running, interspaced by 1 min of passive rest), and 2 randomized TE tests at such intensities. Two-way ANOVA with repeated measures was used to compare the changes in physiological variables during the TE tests and between continuous and intermittent exercise. The intermittent MLSS velocity (MLSSint = 15.26 ± 0.97 km/h) was higher than in the continuous model (MLSScon = 14.53 ± 0.93 km/h), while the TE at MLSScon was longer than MLSSint (68 ± 11 min and 58 ± 15 min, P < .05). Regarding the cardiorespiratory responses, VO2 and respiratory-exchange ratio remained stable during both TE tests while heart rate, ventilation, and rating of perceived exertion presented a significant increase in the last portion of the tests. The results showed a higher tolerance to exercising during MLSScon than during MLSSint in trained runners. Thus, the training volume of an extensive interval session (ratio 5:1) designed at MLSS intensity should take into consideration this higher speed at MLSS and also the lower TE than with continuous exercise.

scholarly journals Age-related differences in performance and fatigability during an isometric quadriceps intermittent fatigue test

2021 ◽  
Author(s):  
Giorgio Varesco ◽  
Eric Luneau ◽  
Léonard Féasson ◽  
Thomas Lapole ◽  
Vianney Rozand
Keyword(s):  
Older Adults ◽  
Contractile Function ◽  
Age Groups ◽  
Femoral Nerve ◽  
Voluntary Activation ◽  
Knee Extensors ◽  
Men And Women ◽  
Very Old ◽  
Old Adults ◽  
Age Related

AbstractThe aim of the present study was to investigate age-related differences in fatigability induced by an isometric quadriceps intermittent fatiguing test in young (<35 years old), old (>60 years old) and very old (>80 years old) men and women. Maximal force loss, contractile function and voluntary activation of the knee extensors were evaluated throughout an isometric fatiguing test using femoral nerve magnetic stimulations. Older adults performed more contractions (index of relative performance) than young (P = 0.046) and very old adults (P = 0.007), without differences between young and very old adults. Total work (absolute performance) was greater for young and old adults compared to very old adults (P < 0.001), without differences between young and old adults. At exhaustion, force loss was greater for young (−28 ± 9%) compared to old adults (−19 ± 8%), but not very old adults (−23 ± 8%). The response to femoral nerve stimulation decreased similarly at exhaustion for the three age groups, indicating similar alteration in contractile function with age. No impairment in voluntary activation was observed. Impairments in neuromuscular parameters were similar for men and women. This study showed that older adults were less fatigable than young adults during an isometric intermittent fatiguing task of the knee extensors. This greater fatigue resistance was not maintained in very old adults independent of sex. Fatigability at exhaustion was likely due to impairments in contractile function for the three age groups.

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