Exercising muscle mass influences neuromuscular, cardiorespiratory, and perceptual responses during and following ramp incremental cycling to task failure

2021 ◽  
Author(s):  
Jenny Zhang ◽  
Danilo Iannetta ◽  
Mohammed Alzeeby ◽  
Martin J. MacInnis ◽  
Saied Jalal Aboodarda
Keyword(s):  
Muscle Mass ◽  
Perceived Exertion ◽  
Central Fatigue ◽  
Exercise Duration ◽  
Peak Oxygen Uptake ◽  
Voluntary Contraction ◽  
Voluntary Activation ◽  
Peak Power Output ◽  
Task Failure ◽  
Single Twitch

Neuromuscular (NM), cardiorespiratory, and perceptual responses to maximal graded exercise using different amounts of active muscle mass remain unclear. We hypothesized that during dynamic exercise, peripheral NM fatigue (declined twitch force) and muscle pain would be greater using smaller muscle mass, whereas central fatigue (declined voluntary activation) and ventilatory variables would be greater using larger muscle mass. Twelve males (29.8±4.7 years) performed two cycling ramp incremental tests until task failure: (i) single-leg (SL) with 10 W·min-1ramp, and (ii) double-leg (DL) with 20 W·min-1ramp. NM fatigue was assessed at baseline, task failure (post), then after 1, 4, and 8 min of recovery. Cardiorespiratory and perceptual variables (i.e., ratings of perceived exertion (RPE), fatigue, pain, dyspnea) were measured throughout cycling. Exercise duration was similar between sessions (SL: 857.7±263.6; DL: 855.0±218.8 s; p=0.923) and higher absolute peak power output was attained in DL (SL: 163.2±43.8; DL: 307.0±72.0 W; p<0.001). While central fatigue did not differ between conditions (SL: -6.6±6.5%; DL: -3.5±4.8%; p=0.091), maximal voluntary contraction (SL: -41.6±10.9%; DL: -33.7±8.5%; p=0.032) and single twitch forces (SL: -59.4±18.8%; DL: -46.2±16.2%; p=0.003) declined more following SL. DL elicited higher peak oxygen uptake (SL: 42.1±10.0; DL:50.3±9.3 mL·kg-1·min-1; p<0.001), ventilation (SL: 137.1±38.1; DL: 171.5±33.2 L·min-1; p<0.001), and heart rate (SL: 167±21; DL: 187±8 bpm; p=0.005). Dyspnea (p=0.025) was higher in DL; however, RPE (p=0.005) and pain (p<0.001) were higher in SL. These results suggest that interplay between NM, cardiorespiratory, and perceptual determinants of exercise performance during incremental cycling to task failure are muscle mass-dependent.

scholarly journals Impact of age on the development of fatigue during large and small muscle mass exercise

2018 ◽  
Vol 315 (4) ◽  
pp. R741-R750 ◽  
Author(s):  
Joshua C. Weavil ◽  
Thomas J. Hureau ◽  
Taylor S. Thurston ◽  
Simranjit K. Sidhu ◽  
Ryan S. Garten ◽  
...  
Keyword(s):  
Muscle Mass ◽  
Relative Intensity ◽  
Femoral Nerve ◽  
Central Fatigue ◽  
Peak Power Output ◽  
Active Muscle ◽  
Task Failure ◽  
Related Difference ◽  
Age Related ◽  
The Impact

To examine the impact of aging on neuromuscular fatigue following cycling (CYC; large active muscle mass) and single-leg knee-extension (KE; small active muscle mass) exercise, 8 young (25 ± 4 years) and older (72 ± 6 years) participants performed CYC and KE to task failure at a given relative intensity (80% of peak power output). The young also matched CYC and KE workload and duration of the old (iso-work comparison). Peripheral and central fatigue were quantified via pre-/postexercise decreases in quadriceps twitch torque (∆Qtw, electrical femoral nerve stimulation) and voluntary activation (∆VA). Although young performed 77% and 33% more work during CYC and KE, respectively, time to task failure in both modalities was similar to the old (~9.5 min; P > 0.2). The resulting ΔQtw was also similar between groups (CYC ~40%, KE ~55%; P > 0.3); however, ∆VA was, in both modalities, approximately double in the young (CYC ~6%, KE ~9%; P < 0.05). While causing substantial peripheral and central fatigue in both exercise modalities in the old, ∆Qtw in the iso-work comparison was not significant (CYC; P = 0.2), or ~50% lower (KE; P < 0.05) in the young, with no central fatigue in either modality ( P > 0.4). Based on iso-work comparisons, healthy aging impairs fatigue resistance during aerobic exercise. Furthermore, comparisons of fatigue following exercise at a given relative intensity mask the age-related difference observed following exercise performed at the same workload. Finally, although active muscle mass has little influence on the age-related difference in the rate of fatigue at a given relative intensity, it substantially impacts the comparison during exercise at a given absolute intensity.

Effects of erythropoietin administration on cerebral metabolism and exercise capacity in men

2010 ◽  
Vol 109 (2) ◽  
pp. 476-483 ◽  
Author(s):  
P. Rasmussen ◽  
E. M. Foged ◽  
R. Krogh-Madsen ◽  
J. Nielsen ◽  
T. R. Nielsen ◽  
...  
Keyword(s):  
Exercise Capacity ◽  
Oxygen Delivery ◽  
Perceived Exertion ◽  
Cerebral Metabolism ◽  
Central Fatigue ◽  
Voluntary Activation ◽  
High Dose ◽  
Ratings Of Perceived Exertion ◽  
Human Erythropoietin ◽  
Double Blinded

Recombinant human erythropoietin (EPO) increases exercise capacity by stimulating erythropoiesis and subsequently enhancing oxygen delivery to the working muscles. In a large dose, EPO crosses the BBB and may reduce central fatigue and improve cognition. In turn, this would augment exercise capacity independent of erythropoiesis. To test this hypothesis, 15 healthy young men (18–34 years old, 74 ± 7 kg) received either 3 days of high-dose (30,000 IU/day; n = 7) double-blinded placebo controlled or 3 mo of low-dose (5,000 IU/wk; n = 8) counter-balanced open but controlled administration of EPO. We recorded exercise capacity, transcranial ultrasonography-derived middle cerebral artery blood velocity, and arterial-internal jugular venous concentration differences of glucose and lactate. In addition, cognitive function, ratings of perceived exertion, ventilation, and voluntary activation by transcranial magnetic stimulation-induced twitch force were evaluated. Although EPO in a high dose increased cerebrospinal fluid EPO concentration ∼20-fold and affected ventilation and cerebral glucose and lactate metabolism ( P < 0.05), 3 days of high-dose EPO administration had no effect on cognition, voluntary activation, or exercise capacity, but ratings of perceived exertion increased ( P < 0.05). We confirmed that 3 mo of administration of EPO increases exercise capacity, but the improvement could not be accounted for by other mechanisms than enhanced oxygen delivery. In conclusion, EPO does not attenuate central fatigue or change cognitive performance strategy, suggesting that EPO enhances exercise capacity exclusively by increased oxygen delivery to the working muscles.

scholarly journals Muscle endurance is greater for old men compared with strength-matched young men

2005 ◽  
Vol 99 (3) ◽  
pp. 890-897 ◽  
Author(s):  
Sandra K. Hunter ◽  
Ashley Critchlow ◽  
Roger M. Enoka
Keyword(s):  
Isometric Contraction ◽  
Perceived Exertion ◽  
Young Men ◽  
Similar Rate ◽  
Voluntary Contraction ◽  
Rating Of Perceived Exertion ◽  
Emg Activity ◽  
Task Failure ◽  
Submaximal Contraction ◽  
Old Men

The purpose was to compare the time to task failure for a sustained isometric contraction performed at a submaximal intensity with the elbow flexor muscles by young and old men who were matched for strength. Eight young men (18–31 yr) and eight old men (67–76 yr) sustained an isometric contraction at 20% of maximal voluntary contraction (MVC) torque until the target torque could no longer be achieved for at least 5 s. The maximal torque exerted at the wrist was similar for the young and old men before the fatiguing task (65.9 ± 8.0 vs. 65.4 ± 8.7 N·m; P > 0.05), and they experienced similar reductions in MVC torque after the fatiguing contraction (31.4 ± 10.6%; P < 0.05). The time to task failure was longer for the old men (22.6 ± 7.4 min) compared with the strength-matched young men (13.0 ± 5.2 min; P < 0.05), despite each group sustaining a similar torque during the fatiguing contraction ( P > 0.05). The increases in torque fluctuations, electromyographic (EMG) bursting activity, and heart rate were greater for young men compared with the old men, and they were less at task failure for the old men ( P < 0.05). Mean arterial pressure increased at a similar rate for both groups of men ( P > 0.05), whereas the averaged EMG activity and rating of perceived exertion reached similar values at task failure for the young and old men ( P > 0.05). These findings indicate that the longer time to task failure for the old men when performing the submaximal contraction was not due the absolute target torque exerted during the contraction.

scholarly journals Hyperthermia and central fatigue during prolonged exercise in humans

2001 ◽  
Vol 91 (3) ◽  
pp. 1055-1060 ◽  
Author(s):  
Lars Nybo ◽  
Bodil Nielsen
Keyword(s):  
Core Temperature ◽  
Maximal Oxygen Consumption ◽  
Knee Extensor ◽  
Central Fatigue ◽  
Knee Extension ◽  
Voluntary Contraction ◽  
Voluntary Activation ◽  
Knee Extensors ◽  
Total Force ◽  
Impaired Performance

The present study investigated the effects of hyperthermia on the contributions of central and peripheral factors to the development of neuromuscular fatigue. Fourteen men exercised at 60% maximal oxygen consumption on a cycle ergometer in hot (40°C; hyperthermia) and thermoneutral (18°C; control) environments. In hyperthermia, the core temperature increased throughout the exercise period and reached a peak value of 40.0 ± 0.1°C (mean ± SE) at exhaustion after 50 ± 3 min of exercise. In control, core temperature stabilized at ∼38.0 ± 0.1°C, and exercise was maintained for 1 h without exhausting the subjects. Immediately after the cycle trials, subjects performed 2 min of sustained maximal voluntary contraction (MVC) either with the exercised legs (knee extension) or with a “nonexercised” muscle group (handgrip). The degree of voluntary activation during sustained maximal knee extensions was assessed by superimposing electrical stimulation (EL) to nervus femoralis. Voluntary knee extensor force was similar during the first 5 s of contraction in hyperthermia and control. Thereafter, force declined in both trials, but the reduction in maximal voluntary force was more pronounced in the hyperthermic trial, and, from 30 to 120 s, the force was significantly lower in hyperthermia compared with control. Calculation of the voluntary activation percentage (MVC/MVC + EL) revealed that the degree of central activation was significantly lower in hyperthermia (54 ± 7%) compared with control (82 ± 6%). In contrast, total force of the knee extensors (MVC + force from EL) was not different in the two trials. Force development during handgrip contraction followed the same pattern of response as was observed for the knee extensors. In conclusion, these data demonstrate that the ability to generate force during a prolonged MVC is attenuated with hyperthermia, and the impaired performance is associated with a reduction in the voluntary activation percentage.

scholarly journals Effects of whole-body vibrations on neuromuscular fatigue: a study with sets of different durations

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10388
Author(s):  
Miloš Kalc ◽  
Ramona Ritzmann ◽  
Vojko Strojnik
Keyword(s):  
High Frequency ◽  
Maximum Voluntary Contraction ◽  
Peak Torque ◽  
Voluntary Contraction ◽  
Neuromuscular Fatigue ◽  
Voluntary Activation ◽  
Whole Body ◽  
Peripheral Fatigue ◽  
Single Twitch ◽  
Whole Body Vibrations

Background Whole body vibrations have been used as an exercise modality or as a tool to study neuromuscular integration. There is increasing evidence that longer WBV exposures (up to 10 minutes) induce an acute impairment in neuromuscular function. However, the magnitude and origin of WBV induced fatigue is poorly understood. Purpose The study aimed to investigate the magnitude and origin of neuromuscular fatigue induced by half-squat long-exposure whole-body vibration intervention (WBV) with sets of different duration and compare it to non-vibration (SHAM) conditions. Methods Ten young, recreationally trained adults participated in six fatiguing trials, each consisting of maintaining a squatting position for several sets of the duration of 30, 60 or 180 seconds. The static squatting was superimposed with vibrations (WBV30, WBV60, WBV180) or without vibrations (SHAM30, SHAM60, SHAM180) for a total exercise exposure of 9-minutes in each trial. Maximum voluntary contraction (MVC), level of voluntary activation (%VA), low- (T20) and high-frequency (T100) doublets, low-to-high-frequency fatigue ratio (T20/100) and single twitch peak torque (TWPT) were assessed before, immediately after, then 15 and 30 minutes after each fatiguing protocol. Result Inferential statistics using RM ANOVA and post hoc tests revealed statistically significant declines from baseline values in MVC, T20, T100, T20/100 and TWPT in all trials, but not in %VA. No significant differences were found between WBV and SHAM conditions. Conclusion Our findings suggest that the origin of fatigue induced by WBV is not significantly different compared to control conditions without vibrations. The lack of significant differences in %VA and the significant decline in other assessed parameters suggest that fatiguing protocols used in this study induced peripheral fatigue of a similar magnitude in all trials.

Comparison of neuromuscular adjustments associated with sustained isometric contractions of four different muscle groups

2013 ◽  
Vol 114 (10) ◽  
pp. 1426-1434 ◽  
Author(s):  
Daria Neyroud ◽  
Jennifer Rüttimann ◽  
Anne F. Mannion ◽  
Guillaume Y. Millet ◽  
Nicola A. Maffiuletti ◽  
...  
Keyword(s):  
Muscle Fatigue ◽  
Upper Limb ◽  
Voluntary Contraction ◽  
Voluntary Activation ◽  
Knee Extensors ◽  
Elbow Flexors ◽  
Plantar Flexors ◽  
Task Failure ◽  
Before And After ◽  
Muscle Groups

The extent and characteristics of muscle fatigue of different muscle groups when subjected to a similar fatiguing task may differ. Thirteen healthy young men performed sustained contractions at 50% maximal voluntary contraction (MVC) force until task failure, with four different muscle groups, over two sessions. Per session, one upper limb and one lower limb muscle group were tested (knee extensors and thumb adductor, or plantar and elbow flexors). Changes in voluntary activation level and contractile properties were derived from doublet responses evoked during and after MVCs before and after exercise. Time to task failure differed ( P < 0.05) between muscle groups (220 ± 64 s for plantar flexors, 114 ± 27 s for thumb adductor, 77 ± 25 s for knee extensors, and 72 ± 14 s for elbow flexors). MVC force loss immediately after voluntary task failure was similar (−30 ± 11% for plantar flexors, −37 ± 13% for thumb adductor, −34 ± 15% for knee extensors, and −40 ± 12% for elbow flexors, P > 0.05). Voluntary activation was decreased for plantar flexors only (from 95 ± 5% to 82 ± 9%, P < 0.05). Potentiated evoked doublet amplitude was more depressed for upper limb muscles (−59.3 ± 14.7% for elbow flexors and −60.1 ± 24.1% for thumb adductor, P < 0.05) than for knee extensors (−28 ± 15%, P < 0.05); no reduction was found in plantar flexors (−7 ± 12%, P > 0.05). In conclusion, despite different times to task failure when sustaining an isometric contraction at 50% MVC force for as long as possible, diverse muscle groups present similar loss of MVC force after task failure. Thus the extent of muscle fatigue is not affected by time to task failure, whereas this latter determines the etiology of fatigue.

scholarly journals Stressor-induced increase in muscle fatigability of young men and women is predicted by strength but not voluntary activation

2014 ◽  
Vol 116 (7) ◽  
pp. 767-778 ◽  
Author(s):  
Manda L. Keller-Ross ◽  
Hugo M. Pereira ◽  
Jaclyn Pruse ◽  
Tejin Yoon ◽  
Bonnie Schlinder-DeLap ◽  
...  
Keyword(s):  
Voluntary Contraction ◽  
Voluntary Activation ◽  
Men And Women ◽  
Task Failure ◽  
Initial Strength ◽  
Math Task ◽  
Flexor Muscles ◽  
Elbow Flexor Muscles ◽  
Induced Changes ◽  
And Control

This study investigated mechanisms for the stressor-induced changes in muscle fatigability in men and women. Participants performed an isometric-fatiguing contraction at 20% maximal voluntary contraction (MVC) until failure with the elbow flexor muscles. Study one ( n = 55; 29 women) involved two experimental sessions: 1) a high-stressor session that required a difficult mental-math task before and during a fatiguing contraction and 2) a control session with no mental math. For some participants (n = 28; 14 women), cortical stimulation was used to examine mechanisms that contributed to muscle fatigability during the high-stressor and control sessions. Study two ( n = 23; nine women) determined the influence of a low stressor, i.e., a simple mental-math task, on muscle fatigability. In study one, the time-to-task failure was less for the high-stressor session than control ( P < 0.05) for women (19.4%) and men (9.5%): the sex difference response disappeared when covaried for initial strength (MVC). MVC force, voluntary activation, and peak-twitch amplitude decreased similarly for the control and high-stressor sessions ( P < 0.05). In study two, the time-to-task failure of men or women was not influenced by the low stressor ( P > 0.05). The greater fatigability, when exposed to a high stressor during a low-force task, was not exclusive to women but involved a strength-related mechanism in both weaker men and women that accelerated declines in voluntary activation and slowing of contractile properties.

The influence of ice slushy on voluntary contraction force following exercise-induced hyperthermia

2014 ◽  
Vol 39 (7) ◽  
pp. 781-786 ◽  
Author(s):  
Catriona A. Burdon ◽  
Christopher S. Easthope ◽  
Nathan A. Johnson ◽  
Phillip G. Chapman ◽  
Helen O’Connor
Keyword(s):  
Muscle Activation ◽  
Force Production ◽  
Central Fatigue ◽  
Voluntary Contraction ◽  
Voluntary Activation ◽  
Peripheral Fatigue ◽  
Knee Extensors ◽  
Central Component ◽  
Induced Hyperthermia ◽  
Exercise Induced

This study aimed to investigate the effect of exercise-induced hyperthermia on central fatigue and force decline in exercised and nonexercised muscles and whether ingestion of ice slushy (ICE) ameliorates fatigue. Eight participants (5 males, 3 females) completed 45 s maximal voluntary isometric contractions (MVIC) with elbow flexors and knee extensors at baseline and following an exercise-induced rectal temperature (Trec) of 39.3 ± 0.2 °C. Percutaneous electrical muscle stimulation was superimposed at 15, 30 and 44 s during MVICs to assess muscle activation. To increase Trec to 39.3 °C, participants cycled at 60% maximum power output for 42 ± 11 min in 40 °C and 50% relative humidity. Immediately prior to each MVIC, participants consumed 50 g of ICE (–1 °C) or thermoneutral drink (38 °C, CON) made from 7.4% carbohydrate beverage. Participants consumed water (19 °C) during exercise to prevent hypohydration. Voluntary muscle force production and activation in both muscle groups were unchanged at Trec 39.3 °C with ICE (knee extensors: 209 ± 152 N) versus CON (knee extensors: 255 ± 157 N, p = 0.19). At Trec 39.3 °C, quadriceps mean force (232 ± 151 N) decreased versus baseline (302 ± 180 N, p < 0.001) and mean voluntary activation was also decreased (by 15% ± 11%, p < 0.001). Elbow flexor mean force decreased from 179 ± 67 N to 148 ± 65 N when Trec was increased to 39.3 °C (p < 0.001) but mean voluntary activation was not reduced at 39.3 °C (5% ± 25%, p = 0.79). After exercise-induced hyperthermia, ICE had no effect on voluntary activation or force production; however, both were reduced from baseline in the exercised muscle group. Peripheral fatigue was greater than the central component and limited the ability of an intervention designed to alter central fatigue.

scholarly journals Men are more fatigable than strength-matched women when performing intermittent submaximal contractions

2004 ◽  
Vol 96 (6) ◽  
pp. 2125-2132 ◽  
Author(s):  
Sandra K. Hunter ◽  
Ashley Critchlow ◽  
In-Sik Shin ◽  
Roger M. Enoka
Keyword(s):  
Perceived Exertion ◽  
Voluntary Contraction ◽  
Elbow Flexor ◽  
Rating Of Perceived Exertion ◽  
Men And Women ◽  
Task Failure ◽  
Rate Of Increase ◽  
Absolute Strength ◽  
Flexor Muscles ◽  
Elbow Flexor Muscles

The purpose of this study was to compare the time to task failure for a series of intermittent submaximal contractions performed with the elbow flexor muscles by men and women who were matched for strength ( n = 20, 18–34 yr). The fatigue task comprised isometric contractions at 50% of maximal voluntary contraction (MVC) torque (6-s contraction, 4-s rest). The MVC torque was similar for the men and women [64.8 ± 9.2 (SD) vs. 62.2 ± 7.9 N·m; P > 0.05]. However, the time to task failure was longer for the women (1,408 ± 1,133 vs. 513 ± 194 s; P < 0.05), despite the similar torque levels. The mean arterial pressure, heart rate, and rating of perceived exertion started and ended at similar values for the men and women, but the rate of increase was less for the women. The rate of increase in the average of the rectified electromyogram (AEMG; % peak MVC) for the elbow flexor muscles was less for the women: the AEMG was greater for the men compared with the women at task failure (72 ± 28 vs. 50 ± 21%; P < 0.05), despite similar AEMG values at the start of the fatiguing contraction (32 ± 9 vs. 36 ± 13%). These results indicate that for intermittent contractions performed with the elbow flexor muscles 1) the sex difference in time to task failure was not explained by the absolute strength of the men and women, but involved another mechanism that is present during perfused conditions, and 2) men required a more rapid increase in descending drive to maintain a similar torque.

scholarly journals High tempo music prolongs high intensity exercise

2018 ◽  
Author(s):  
Meaghan Maddigan ◽  
Kathleen M Sullivan ◽  
Fabien A Basset ◽  
Israel Halperin ◽  
David G Behm
Keyword(s):  
High Intensity ◽  
Peak Power ◽  
Perceived Exertion ◽  
Exercise Duration ◽  
Rating Of Perceived Exertion ◽  
Moderate Intensity ◽  
Peak Power Output ◽  
Motor Drive ◽  
Breathing Frequency ◽  
Exercise Enjoyment

Music has been shown to reduce rating of perceived exertion, increase exercise enjoyment and enhance exercise performance, mainly in low-moderate intensity exercises. However, the effects of music are less conclusive with high-intensity activities. The purpose of this study was to compare the effects of high tempo music (130 bpm) to a no-music condition during repeated high intensity cycling bouts (80% of peak power output (PPO)) on the following measures: time to task failure (TTF), rating of perceived exertion (RPE), heart rate (HR), breathing frequency, ventilatory kinetics and blood lactate (BL). Under the music condition, participants exercised 10.7% longer (p = 0.035; Effect size (ES)= 0.28) (increase of one minute) and had higher HR (4%; p= 0.043; ES= 0.25), breathing frequency (11.6%; p= 0.0006; ES= 0.57), and RER (7% at TTF; p= 0.021; ES=1 .1) during exercise. Trivial differences were observed between conditions in RPE and other ventilatory kinetics during exercise. Interestingly, HR recovery was 13.0% faster following the music condition (p< 0.05). These results strengthen the notion that music can alter the association between central motor drive, central cardiovascular command and perceived exertion, and contribute to prolonged exercise duration at higher intensities along with a quicken HR recovery.

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