scholarly journals The Effect of Elevated Muscle Pain on Neuromuscular Fatigue during Exercise

2021 ◽  
Author(s):  
Ryan Norbury ◽  
Samuel Smith ◽  
Mark Burnley ◽  
Megan Judge ◽  
Alexis Mauger
Keyword(s):  
Exercise Performance ◽  
Muscle Pain ◽  
Vastus Lateralis ◽  
Isotonic Saline ◽  
Silent Period ◽  
Neuromuscular Fatigue ◽  
Voluntary Activation ◽  
Knee Extensors ◽  
Group Iii ◽  
The Right

Purpose: Muscle pain can impair exercise performance but the mechanisms for this are unknown. This study examined the effects of muscle pain on neuromuscular fatigue during an endurance task. Methods: On separate visits, twelve participants completed an isometric time to task failure (TTF) of the right knee extensors at ~20% of maximum force following an intramuscular injection of isotonic saline (CTRL) or hypertonic saline (HYP) into the vastus lateralis. Measures of neuromuscular fatigue were taken before, during and after the TTF using transcranial magnetic stimulation (TMS) and peripheral nerve stimulation (PNS). Results: The mean pain intensity was 57 ± 10 in HYP compared to 38 ± 18 in CTRL (P < 0.001). TTF was reduced in HYP (4.36 ± 0.88 min) compared to CTRL (5.20 ± 0.39 min) (P = 0.003). Maximum voluntary force was 12 % lower at minute 1 (P = 0.003) and 11 % lower at minute 2 in HYP (P = 0.013) compared to CTRL. Voluntary activation was 4 % lower at minute 1 in HYP compared to CTRL (P = 0.006) but not at any other time point (all P > 0.05). The TMS silent period was 9 % longer at 100 s during the TTF in HYP compared to CTRL (P = 0.026). Conclusion: Muscle pain reduces exercise performance through the excacerbation of neuromuscular fatigue that is central in origin. This appears to be from inhibitory feedback from group III/IV nociceptors which acts to reduce central motor output.

scholarly journals The effect of elevated muscle pain on neuromuscular fatigue during exercise

2021 ◽  
Author(s):  
Ryan Norbury ◽  
Samuel A. Smith ◽  
Mark Burnley ◽  
Megan Judge ◽  
Alexis R. Mauger
Keyword(s):  
Exercise Performance ◽  
Muscle Pain ◽  
Vastus Lateralis ◽  
Isotonic Saline ◽  
Silent Period ◽  
Neuromuscular Fatigue ◽  
Voluntary Activation ◽  
Knee Extensors ◽  
Group Iii ◽  
The Right

Abstract Purpose Muscle pain can impair exercise performance but the mechanisms for this are unknown. This study examined the effects of muscle pain on neuromuscular fatigue during an endurance task. Methods On separate visits, twelve participants completed an isometric time-to-task failure (TTF) exercise of the right knee extensors at ~ 20% of maximum force following an intramuscular injection of isotonic saline (CTRL) or hypertonic saline (HYP) into the vastus lateralis. Measures of neuromuscular fatigue were taken before, during and after the TTF using transcranial magnetic stimulation (TMS) and peripheral nerve stimulation. Results The mean pain intensity was 57 ± 10 in HYP compared to 38 ± 18 in CTRL (P < 0.001). TTF was reduced in HYP (4.36 ± 0.88 min) compared to CTRL (5.20 ± 0.39 min) (P = 0.003). Maximum voluntary force was 12% lower at minute 1 (P = 0.003) and 11% lower at minute 2 in HYP (P = 0.013) compared to CTRL. Voluntary activation was 4% lower at minute 1 in HYP compared to CTRL (P = 0.006) but not at any other time point (all P > 0.05). The TMS silent period was 9% longer at 100 s during the TTF in HYP compared to CTRL (P = 0.026). Conclusion Muscle pain reduces exercise performance through the excacerbation of neuromuscular fatigue that is central in origin. This appears to be from inhibitory feedback from group III/IV nociceptors which acts to reduce central motor output.

scholarly journals Acute Quadriceps Muscle Pain Reduces Isometric Endurance Performance of the Contralateral Limb

2021 ◽  
Author(s):  
Ryan Norbury ◽  
Samuel Smith ◽  
Mark Burnley ◽  
Megan Judge ◽  
Alexis Mauger
Keyword(s):  
Muscle Pain ◽  
Vastus Lateralis ◽  
Isotonic Saline ◽  
Endurance Performance ◽  
Quadriceps Muscle ◽  
Neuromuscular Fatigue ◽  
Voluntary Activation ◽  
Knee Extensors ◽  
Contralateral Limb ◽  
Non Local

Intro: Non-local muscle pain may impair neuromuscular fatigue and endurance performance, but the mechanisms are unknown. This study examined the effects of muscle pain on neuromuscular performance of the contralateral limb. Methods: On separate visits, nine participants completed an isometric time to task failure (TTF) of the right knee extensors after intramuscular injection of isotonic saline (CTRL) or hypertonic saline (HYP) into the left vastus lateralis. Measures of neuromuscular fatigue were taken before, during and after the TTF using transcranial magnetic stimulation (TMS) and peripheral nerve stimulation. Results: Mean pain intensity was greater in the left leg in HYP (3.3 ± 1.9) compared to CTRL (0.4 ± 0.7) (P &lt; 0.001) which reduced TTF by 9.8% in HYP (4.54 ± 0.56 min) compared to CTRL (5.07 ± 0.77 min) (P = 0.005). Maximum voluntary force was not different between conditions (all P &gt; 0.05). Voluntary activation was lower at minute 3 of the TTF in HYP compared to CTRL (P = 0.016). No difference was identified between conditions for doublet amplitude (all P &lt; 0.05). Furthermore, no difference in TMS responses between conditions was observed. Conclusion: Non-local pain impairs endurance performance of the contralateral limb. This impairment in performance is likely due to the faster attainment of the sensory tolerance limit from a greater amount of sensory feedback originating from the non-exercising, but painful, left leg.

Central and peripheral contributions to neuromuscular fatigue induced by a 24-h treadmill run

2010 ◽  
Vol 108 (5) ◽  
pp. 1224-1233 ◽  
Author(s):  
Vincent Martin ◽  
Hugo Kerhervé ◽  
Laurent A. Messonnier ◽  
Jean-Claude Banfi ◽  
André Geyssant ◽  
...  
Keyword(s):  
Compound Muscle Action Potential ◽  
Vastus Lateralis ◽  
Low Frequency ◽  
Force Production ◽  
Neuromuscular Fatigue ◽  
Voluntary Activation ◽  
Knee Extensors ◽  
Function Evaluation ◽  
Central Component ◽  
Low Frequency Fatigue

This experiment investigated the fatigue induced by a 24-h running exercise (24TR) and particularly aimed at testing the hypothesis that the central component would be the main mechanism responsible for neuromuscular fatigue. Neuromuscular function evaluation was performed before, every 4 h during, and at the end of the 24TR on 12 experienced ultramarathon runners. It consisted of a determination of the maximal voluntary contractions (MVC) of the knee extensors (KE) and plantar flexors (PF), the maximal voluntary activation (%VA) of the KE and PF, and the maximal compound muscle action potential amplitude (Mmax) on the soleus and vastus lateralis. Tetanic stimulations also were delivered to evaluate the presence of low-frequency fatigue and the KE maximal muscle force production ability. Strength loss occurred throughout the exercise, with large changes observed after 24TR in MVC for both the KE and PF muscles (−40.9 ± 17.0 and −30.3 ± 12.5%, respectively; P < 0.001) together with marked reductions of %VA (−33.0 ± 21.8 and −14.8 ± 18.9%, respectively; P < 0.001). A reduction of Mmax amplitude was observed only on soleus, and no low-frequency fatigue was observed for any muscle group. Finally, KE maximal force production ability was reduced to a moderate extent at the end of the 24TR (−10.2%; P < 0.001), but these alterations were highly variable ( ± 15.7%). These results suggest that central factors are mainly responsible for the large maximal muscle torque reduction after ultraendurance running, especially on the KE muscles. Neural drive reduction may have contributed to the relative preservation of peripheral function and also affected the evolution of the running speed during the 24TR.

scholarly journals Muscle pain from an intramuscular injection of hypertonic saline increases variability in knee extensor torque reproduction

2020 ◽  
Author(s):  
Samuel Andrew Smith ◽  
Dominic Micklewright ◽  
Samantha Lee Winter ◽  
Alexis R. Mauger
Keyword(s):  
Hypertonic Saline ◽  
Muscle Pain ◽  
Intramuscular Injection ◽  
Vastus Lateralis ◽  
Isotonic Saline ◽  
Knee Extensor ◽  
Knee Extensors ◽  
Saline Control ◽  
Reproduction Task ◽  
Extensor Torque

Purpose: The intensity of exercise-induced pain (EIP) reflects the metabolic environment in the exercising muscle, so during endurance exercise this may inform the intelligent regulation of work rate. Conversely, the acute debilitating effects of EIP on motor unit recruitment could impair the estimation of force produced by the muscle and impair judgement of current exercise intensity. This study investigated whether muscle pain that feels like EIP, administered via intramuscular injection of hypertonic saline, interferes with the ability to accurately reproduce torque in a muscle group relevant to locomotive exercise. Methods: On separate days, fourteen participants completed an isometric torque reproduction task of the knee extensors. Participants were required to produce torque at 15 and 20% maximal voluntary torque (MVIT), without visual feedback before (Baseline), during (Pain/No Pain), and after (Recovery) an injection of 0.9% isotonic saline (Control) or 5.8% hypertonic saline (Experimental) into the vastus lateralis of the right leg. Results: An elevated reported intensity of pain, and a significantly increased variance in mean contraction torque at both 15% (P=0.049) and 20% (P=0.002) MVIT was observed in the Experimental compared to the Control condition. Both 15 and 20% target torques were performed at a similar pain intensity in the Experimental condition (15% MVIT, 4.2 ± 1.9; 20% MVIT, 4.5 ± 2.2; P>0.05). Conclusion: These findings demonstrate that the increased muscle pain from the injection of hypertonic saline impeded accurate reproduction of knee extensor torque. These findings have implications for the detrimental impact of EIP on exercise regulation and endurance performance.

Neural adaptations in quadriceps muscle after 4 weeks of local vibration training in young versus older subjects

2018 ◽  
Vol 43 (5) ◽  
pp. 427-436 ◽  
Author(s):  
Robin Souron ◽  
Thibault Besson ◽  
Thomas Lapole ◽  
Guillaume Y. Millet
Keyword(s):  
Vastus Lateralis ◽  
Motor Evoked Potential ◽  
Silent Period ◽  
Voluntary Activation ◽  
Knee Extensors ◽  
Emg Activity ◽  
Local Vibration ◽  
Jump Performance ◽  
Vibration Training ◽  
Older Subjects

This study investigated the effects of a 4-week local vibration training (LVT) on the function of the knee extensors and corticospinal properties in healthy young and older subjects. Seventeen subjects (9 young and 8 older) performed 3 testing sessions: before (PRE1) and after (PRE2) a 4-week resting period to control the repeatability of the data as well as after the LVT (POST). Jump performance, maximal voluntary contraction (MVC) and electromyographic (EMG) activity on vastus lateralis and rectus femoris muscles were assessed. Single-pulse transcranial magnetic stimulation (TMS) allowed evaluation of cortical voluntary activation (VATMS), motor evoked potential (MEP) area, and silent period (SP) duration. All training adaptations were similar between young and older subjects (p > 0.05) and the following results reflect the pooled sample of subjects. MVC (+11.9% ± 8.0%, p < 0.001) and VATMS (+3.6% ± 5.2%, p = 0.004) were significantly increased at POST compared with PRE2. Maximal vastus lateralis EMG was significantly increased at POST (+21.9% ± 33.7%, p = 0.03). No changes were reported for MEPs on both muscles (p > 0.05). SPs recorded during maximal and submaximal contractions decreased in both muscles at POST (p < 0.05). Vertical jump performance was increased at POST (p < 0.05). LVT seems as effective in young as in older subjects to improve maximal functional capacities through neural modulations occurring at least partly at the supra-spinal level. Local vibration may be used as an efficient alternative training method to improve muscular performance in both healthy young and older subjects.

Neuromuscular Fatigue After a Ski Skating Marathon

2003 ◽  
Vol 28 (3) ◽  
pp. 434-445 ◽  
Author(s):  
Guillaume Y. Millet ◽  
Vincent Martin ◽  
Nicola A. Maffiuletti ◽  
Alain Martin
Keyword(s):  
Mechanical Response ◽  
Compound Muscle Action Potential ◽  
Vastus Lateralis ◽  
Femoral Nerve ◽  
Voluntary Contraction ◽  
Neuromuscular Fatigue ◽  
Voluntary Activation ◽  
Knee Extensors ◽  
Vastus Lateralis Muscle ◽  
Central Activation

The aim of this study was to characterize neuromuscular fatigue in knee extensor muscles after a marathon skiing race (mean ± SD duration = 159.7 ± 17.9 min). During the 2 days preceding the event and immediately after, maximal percutaneous electrical stimulations (single twitch, 0.5-s tetanus at 20 and 80 Hz) were applied to the femoral nerve of 11 trained skiers. Superimposed twitches were also delivered during maximal voluntary contraction (MVC) to determine maximal voluntary activation (%VA). EMG was recorded from the vastus lateralis muscle. MVC decreased with fatigue from 171.7 ± 33.7 to 157.3 ± 35.2 Nm (-8.4%; p < 0.005) while %VA did not change significantly. The RMS measured during MVC and peak-to-peak amplitude of the compound muscle action potential (PPA) from the vastus lateralis decreased with fatigue by about 30% (p < 0.01), but RMS•PPA−1was similar before and after the ski marathon. Peak tetanus tension at 20 Hz and 80 Hz (P020 and P080, respectively) did not change significantly, but P020•P080−1 increased (p < 0.05) after the ski marathon. Data from electrically evoked single twitches showed greater peak mechanical response, faster rate of force development, and shorter contraction time in the fatigued state. From these results it can be concluded that a ski skating marathon (a) alters slightly but significantly maximal voluntary strength of the knee extensors without affecting central activation, and (b) induces both potentiation and fatigue. Key words: low- and high-frequency electrical stimulation, central activation, potentiation

Distinct profiles of neuromuscular fatigue during muscle contractions below and above the critical torque in humans

2012 ◽  
Vol 113 (2) ◽  
pp. 215-223 ◽  
Author(s):  
Mark Burnley ◽  
Anni Vanhatalo ◽  
Andrew M. Jones
Keyword(s):  
Vastus Lateralis ◽  
Central Fatigue ◽  
Neuromuscular Fatigue ◽  
Voluntary Activation ◽  
Peripheral Fatigue ◽  
Critical Threshold ◽  
Task Failure ◽  
Fatigue Development ◽  
The Right ◽  
Experimental Trials

Whether the transition in fatigue processes between “low-intensity” and “high-intensity” contractions occurs gradually, as the torque requirements are increased, or whether this transition occurs more suddenly at some identifiable “threshold”, is not known. We hypothesized that the critical torque (CT; the asymptote of the torque-duration relationship) would demarcate distinct profiles of central and peripheral fatigue during intermittent isometric quadriceps contractions (3-s contraction, 2-s rest). Nine healthy men performed seven experimental trials to task failure or for up to 60 min, with maximal voluntary contractions (MVCs) performed at the end of each minute. The first five trials were performed to determine CT [∼35–55% MVC, denoted severe 1 (S1) to severe 5 (S5) in ascending order], while the remaining two trials were performed 10 and 20% below the CT (denoted CT-10% and CT-20%). Dynamometer torque and the electromyogram of the right vastus lateralis were sampled continuously. Peripheral and central fatigue was determined from the fall in potentiated doublet torque and voluntary activation, respectively. Above CT, contractions progressed to task failure in ∼3–18 min, at which point the MVC did not differ from the target torque (S1 target, 88.7 ± 4.3 N·m vs. MVC, 89.3 ± 8.8 N·m, P = 0.94). The potentiated doublet fell significantly in all trials, and voluntary activation was reduced in trials S1–S3, but not trials S4 and S5. Below CT, contractions could be sustained for 60 min on 17 of 18 occasions. Both central and peripheral fatigue developed, but there was a substantial reserve in MVC torque at the end of the task. The rate of global and peripheral fatigue development was four to five times greater during S1 than during CT-10% (change in MVC/change in time S1 vs. CT-10%: −7.2 ± 1.4 vs. −1.5 ± 0.4 N·m·min−1). These results demonstrate that CT represents a critical threshold for neuromuscular fatigue development.

Effect of voluntary vs. artificial activation on the relationship of muscle torque to speed

1990 ◽  
Vol 69 (6) ◽  
pp. 2215-2221 ◽  
Author(s):  
G. A. Dudley ◽  
R. T. Harris ◽  
M. R. Duvoisin ◽  
B. M. Hather ◽  
P. Buchanan
Keyword(s):  
Knee Extensor ◽  
Voluntary Activation ◽  
Knee Extensors ◽  
Angular Velocities ◽  
The Central Nervous System ◽  
The Right ◽  
Artificial Activation ◽  
Relationship Of ◽  
The Relationship ◽  
Eccentric Actions

The speed-torque relationship of the right knee extensor muscle group was investigated in eight untrained subjects (28 +/- 2 yr old). Torque was measured at a specific knee angle during isokinetic concentric or eccentric actions at nine angular velocities (0.17-3.66 rad/s) and during isometric actions. Activation was by "maximal" voluntary effort or by transcutaneous tetanic electrical stimulation that induced an isometric torque equal to 60% (STIM 1) or 45% (STIM 2) of the voluntary isometric value. Torque increased (P less than 0.05) to 1.4 times isometric as the speed of eccentric actions increased to 1.57 rad/s for STIM 1 and STIM 2. Thereafter, increases in eccentric speed did not further increase torque. Torque did not increase (P greater than 0.05) above isometric for voluntary eccentric actions. As the speed of concentric actions increased from 0.00 to 3.66 rad/s, torque decreased (P less than 0.05) more (P less than 0.05) for both STIM 1 and STIM 2 (two-thirds) than for voluntary activation (one-half). As a result of these responses, torque changed three times as much (P less than 0.05) across speeds of concentric and eccentric actions with artificial (3.4-fold) than voluntary (1.1-fold) activation. The results indicate that with artificial activation the normalized speed-torque relationship of the knee extensors in situ is remarkably similar to that of isolated muscle. The relationship for voluntary activation, in contrast, suggests that the ability of the central nervous system to activate the knee extensors during maximal efforts depends on the speed and type of muscle action performed.

scholarly journals The effect of rolling massage on the excitability of the corticospinal pathway

2018 ◽  
Vol 43 (4) ◽  
pp. 317-323 ◽  
Author(s):  
Saied J. Aboodarda ◽  
Rebecca M. Greene ◽  
Devin T. Philpott ◽  
Ramandeep S. Jaswal ◽  
Guillaume Y. Millet ◽  
...  
Keyword(s):  
Compound Muscle Action Potential ◽  
Vastus Lateralis ◽  
Femoral Nerve ◽  
Motor Evoked Potential ◽  
Silent Period ◽  
Knee Extensors ◽  
Electromyographic Activity ◽  
Muscle Action Potential ◽  
Central Excitability ◽  
Electrical Stimuli

The aim of the present study was to investigate the alterations of corticospinal excitability (motor evoked potential, MEP) and inhibition (silent period, SP) following rolling massage of the quadriceps muscles. Transcranial magnetic and femoral nerve electrical stimuli were used to elicit MEPs and compound muscle action potential (Mmax) in the vastus lateralis and vastus medialis muscles prior to and following either (i) 4 sets of 90-s rolling massage (ROLLING) or (ii) rest (CONTROL). One series of neuromuscular evaluations, performed after each set of ROLLING or CONTROL, included 3 MEPs and 1 Mmax elicited every 4 s during 15-s submaximal contractions at 10% (experiment 1, n = 16) and 50% (experiment 2, n = 10) of maximal voluntary knee extensions (MVC). The MEP/Mmax ratio and electromyographic activity recorded from vastus lateralis at 10% MVC demonstrated significantly lower values during ROLLING than CONTROL (P < 0.05). The ROLLING did not elicit any significant changes in muscle excitability (Mmax area) and duration of transcranial magnetic stimulation-induced SP recorded from any muscle or level of contraction (P > 0.05). The findings suggest that rolling massage can modulate the central excitability of the circuitries innervating the knee extensors; however, the observed effects are dependent on the background contraction intensity during which the neuromuscular measurements are recorded.

scholarly journals A Methodological Framework to Capture Neuromuscular Fatigue Mechanisms Under Stress

2021 ◽  
Vol 2 ◽  
Author(s):  
Oshin Tyagi ◽  
Ranjana K. Mehta
Keyword(s):  
Imaging Techniques ◽  
Motor Evoked Potential ◽  
Silent Period ◽  
Central Fatigue ◽  
Brain Regions ◽  
Functional Brain Imaging ◽  
Neuromuscular Fatigue ◽  
Voluntary Activation ◽  
Electromyographic Activity ◽  
Fatigue Development

Neuromuscular fatigue is exacerbated under stress and is characterized by shorter endurance time, greater perceived effort, lower force steadiness, and higher electromyographic activity. However, the underlying mechanisms of fatigue under stress are not well-understood. This review investigated existing methods of identifying central mechanisms of neuromuscular fatigue and the potential mechanisms of the influence of stress on neuromuscular fatigue. We found that the influence of stress on the activity of the prefrontal cortex, which are also involved in exercise regulation, may contribute to exacerbated fatigue under stress. We also found that the traditional methods involve the synchronized use of transcranial magnetic stimulation, peripheral nerve stimulation, and electromyography to identify the contribution of supraspinal fatigue, through measures such as voluntary activation, motor evoked potential, and silent period. However, these popular techniques are unable to provide information about neural alterations upstream of the descending drive that may contribute to supraspinal fatigue development. To address this gap, we propose that functional brain imaging techniques, which provide insights on activation and information flow between brain regions, need to be combined with the traditional measures of measuring central fatigue to fully understand the mechanisms behind the influence of stress on fatigue.

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