The Effect of Heating and Cooling on Time Course of Voluntary and Electrically Induced Muscle Force Variation

Medicina ◽  
2011 ◽  
Vol 47 (1) ◽  
pp. 6 ◽  
Author(s):  
◽  
◽  
◽  
◽  
Keyword(s):  
Muscle Fatigue ◽  
Time Course ◽  
Muscle Force ◽  
Peak Torque ◽  
Voluntary Contraction ◽  
Knee Extensors ◽  
Lower Body ◽  
Heating And Cooling ◽  
Force Variation ◽  
Voluntary Contractions

The aim of this study was to investigate the effect of heating and cooling on time course of voluntary and electrically induced muscle force variation. Material and Methods. Ten volunteers performed 50 maximal voluntary and electrically induced contractions of the knee extensors at an angle of 120 degrees under the control conditions and after passive lower body heating and cooling in the control, heating, and cooling experiments. Peak torque, torque variation, and half-relaxation time were assessed during the exercise. Results. Passive lower body heating increased muscle and core temperatures, while cooling lowered muscle temperature, but did not affect core temperature. We observed significantly lower muscle fatigue during voluntary contraction compared with electrically induced contractions. Body heating (opposite to cooling) increased involuntarily induced muscle force, but caused greater electrically induced muscle fatigue. In the middle of the exercise, the coefficient of correlation for electrically induced muscle torque decreased significantly as compared with the beginning of the exercise, while during maximal voluntary contractions, this relation for torque remained significant until the end of the exercise. Conclusion. It was shown that time course of voluntary contraction was more stable than in electrically induced contractions.

Unilateral isometric muscle fatigue decreases force production and activation of contralateral knee extensors but not elbow flexors

2014 ◽  
Vol 39 (12) ◽  
pp. 1338-1344 ◽  
Author(s):  
Israel Halperin ◽  
David Copithorne ◽  
David G. Behm
Keyword(s):  
Muscle Fatigue ◽  
Force Production ◽  
Voluntary Activation ◽  
Knee Extensors ◽  
Elbow Flexors ◽  
Post Intervention ◽  
Nonlocal Effects ◽  
And Performance ◽  
Voluntary Contractions ◽  
Isometric Muscle

Nonlocal muscle fatigue occurs when fatiguing 1 muscle alters performance of another rested muscle. The purpose of the study was to investigate if fatiguing 2 separate muscles would affect the same rested muscle, and if fatiguing the same muscle would affect 2 separate muscles. Twenty-one trained males participated in 2 studies (n = 11; n = 10). Subjects performed 2 pre-test maximum voluntary contractions (MVCs) with the nondominant knee extensors. Thereafter they performed two 100-s MVCs with their dominant knee extensors, elbow flexors, or rested. Between and after the sets, a single MVC with the nondominant rested knee extensors was performed. Subsequently, 12 nondominant knee extensors repeated MVCs were completed. Force, quadriceps voluntary activation (VA), and electromyography (EMG) were measured. The same protocol was employed in study 2 except the nondominant elbow-flexors were tested. Study 1: Compared with control conditions, a significant decrease in nondominant knee extensors force, EMG, and VA was found under both fatiguing conditions (P ≤ 0.05; effect size (ES) = 0.91–1.15; 2%–8%). Additionally, decrements in all variables were found from the first post-intervention MVC to the last (P ≤ 0.05; ES = 0.82–2.40; 9%–20%). Study 2: No differences were found between conditions for all variables (P ≥ 0.33; ES ≤ 0.2; ≤3.0%). However, all variables decreased from the first post-intervention MVC to the last (P ≤ 0.05; ES = 0.4–3.0; 7.2%–19.7%). Whereas the rested knee extensors demonstrated nonlocal effects regardless of the muscle being fatigued, the elbow-flexors remained unaffected. This suggests that nonlocal effects are muscle specific, which may hold functional implications for training and performance.

scholarly journals Pre-Exercise Rehydration Attenuates Central Fatigability during 2-Min Maximum Voluntary Contraction in Hyperthermia

Medicina ◽  
2019 ◽  
Vol 55 (3) ◽  
pp. 66
Author(s):  
Kazys Vadopalas ◽  
Aivaras Ratkevičius ◽  
Albertas Skurvydas ◽  
Saulė Sipavičienė ◽  
Marius Brazaitis
Keyword(s):  
Body Weight ◽  
Physiological Stress ◽  
Maximum Voluntary Contraction ◽  
Thermal Strain ◽  
Plasma Osmolality ◽  
Voluntary Contraction ◽  
Whole Body ◽  
Knee Extensors ◽  
Lower Body ◽  
Whole Body Hyperthermia

Background and objectives: Hyperthermia with dehydration alters several brain structure volumes, mainly by changing plasma osmolality, thus strongly affecting neural functions (cognitive and motor). Here, we aimed to examine whether the prevention of significant dehydration caused by passively induced whole-body hyperthermia attenuates peripheral and/or central fatigability during a sustained 2-min isometric maximal voluntary contraction (MVC). Materials and Methods: Ten healthy and physically active adult men (21 ± 1 years of age) performed an isometric MVC of the knee extensors for 2 min (2-min MVC) under control (CON) conditions, after passive lower-body heating that induced severe whole-body hyperthermia (HT, Tre > 39 °C) with dehydration (HT-D) and after HT with rehydration (HT-RH). Results: In the HT-D trial, the subjects lost 0.94 ± 0.15 kg (1.33% ± 0.13%) of their body weight; in the HT-RH trial, their body weight increased by 0.1 ± 0.42 kg (0.1% ± 0.58%). After lower-body heating, the HT-RH trial (vs. HT-D trial) was accompanied by a significantly lower physiological stress index (6.77 ± 0.98 vs. 7.40 ± 1.46, respectively), heart rate (47.8 ± 9.8 vs. 60.8 ± 13.2 b min−1, respectively), and systolic blood pressure (−12.52 ± 5.1 vs. +2.3 ± 6.4, respectively). During 2-min MVC, hyperthermia (HT-D; HT-RH) resulted in greater central fatigability compared with the CON trial. The voluntary activation of exercising muscles was less depressed in the HT-RH trial compared with the HT-D trial. Over the exercise period, electrically (involuntary) induced torque decreased less in the HT-D trial than in the CON and HT-RH trials. Conclusions: Our results suggest that pre-exercise rehydration might have the immediate positive effect of reducing physiological thermal strain, thus attenuating central fatigability even when exercise is performed during severe (Tre > 39 °C) HT, induced by passive warming of the lower body.

The effects of priming exercise on the V̇O2 slow component and the time-course of muscle fatigue during very-heavy-intensity exercise in humans

2018 ◽  
Vol 43 (9) ◽  
pp. 909-919 ◽  
Author(s):  
Paulo Cesar do Nascimento Salvador ◽  
Kristopher Mendes de Souza ◽  
Ricardo Dantas De Lucas ◽  
Luiz Guilherme Antonacci Guglielmo ◽  
Benedito Sérgio Denadai
Keyword(s):  
Muscle Fatigue ◽  
Time Course ◽  
Slow Component ◽  
Peak Torque ◽  
Fixed Amount ◽  
Prior Exercise ◽  
Before And After ◽  
Priming Exercise ◽  
Male Subjects ◽  
Exercise In Humans

We hypothesized that prior exercise would attenuate the muscle fatigue accompanied by oxygen uptake slow-component (V̇O2SC) behavior during a subsequent very-heavy (VH)-intensity cycling exercise. Thirteen healthy male subjects performed tests to determine the critical power (CP) and the fixed amount of work above CP ([Formula: see text]) and performed 6 square-wave bouts until 3 or 8 min, each at a work rate set to deplete 70% [Formula: see text] in 8 min, with a maximal isokinetic effort before and after the conditions without (VHCON) and with prior exercise (VHEXP), to measure the cycling peak torque decrement. The V̇O2SC magnitude at 3 min (VHCON = 0.280 ± 0.234, VHEXP = 0.116 ± 0.109 L·min−1; p = 0.04) and the V̇O2SC trajectory were significantly lower for VHEXP (VHCON = 0.108 ± 0.042, VHEXP = 0.063 ± 0.031 L·min−2; p < 0.01), leading to a V̇O2SC magnitude at the eighth minute that was significantly lower than VHCON (VHCON = 0.626 ± 0.296 L·min−1, VHEXP = 0.337 ± 0.179; p < 0.01). Conversely, peak torque progressively decreased from pre-exercise to 3 min (Δtorque = 21.5 ± 7.7 vs. 19.6 ± 9.2 Nm) and to 8 min (Δtorque = 29.4 ± 15.8 vs. 27.5 ± 12.0 Nm) at VHCON and VHEXP, respectively, without significant differences between conditions. Regardless of the condition, there was a significant relationship between Δtorque and the V̇O2SC (R2: VHCON = 0.23, VHEXP = 0.25; p = 0.01). Considering that “priming” effects on the V̇O2SC were not accompanied by the muscle force behavior, these findings do not support the hypothesis of a “causal” relationship between the time-course of muscle fatigue and V̇O2SC.

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.

scholarly journals Influence of heating and cooling on muscle fatigue and recovery

Medicina ◽  
2008 ◽  
Vol 44 (9) ◽  
pp. 687 ◽  
Author(s):  
Irina Ramanauskienė ◽  
Albertas Skurvydas ◽  
Saulė Sipavičienė ◽  
Žibuoklė Senikienė ◽  
Vitas Linonis ◽  
...  
Keyword(s):  
Creatine Kinase ◽  
Blood Serum ◽  
Muscle Contraction ◽  
Muscle Fatigue ◽  
Kinase Activity ◽  
Creatine Kinase Activity ◽  
Knee Extensors ◽  
Contraction Force ◽  
Heating And Cooling ◽  
Muscle Cooling

The aim of the present study was to establish the influence of muscle heating and cooling on knee flexors and extensors during fatiguing exercise. The participants of the study were 10 healthy males aged 19–23 years. The participants of the study were tested with the isokinetic dynamometer. Control measurements were done before the load as well as 10 min, 30 min, 60 min, and 24 h after the load. The participants performed concentric exercise bouts: 50 knee extensions and flexions at the fixed speed of 180°/s, when femoral muscles before concentric load were of normal temperature, were heated or cooled. Creatine kinase activity in blood serum was estimated 1 h before the load and 24 h after it. Internal temperature of the muscle quadriceps femoris after muscle heating for 45 min increased to 39.5±0.2°C (P<0.001) and after muscle cooling for 30 min decreased to 32.5±0.3°C (P<0.05) as compared to baseline temperature (before heating – 36.9±0.1°C, before cooling – 36.8±0.2°C). Creatine kinase activity in blood serum 24 h after concentric load was significantly increased as compared to control values. Passive muscle warming increased muscle contraction force of knee extensors, but did not cause any changes either in the rate of muscle fatigue or in the rate of muscle recovery. Muscle cooling did not decrease muscle contraction force and did not increase muscle fatigue resistance. The findings of this study showed that both, muscle warming and muscle cooling, brought about a decrease in an indirect parameter of muscle damage – the amount of creatine kinase 24 h after concentric load.

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 Motoneuron excitability of the quadriceps decreases during a fatiguing submaximal isometric contraction

2018 ◽  
Vol 124 (4) ◽  
pp. 970-979 ◽  
Author(s):  
Harrison T. Finn ◽  
David M. Rouffet ◽  
David S. Kennedy ◽  
Simon Green ◽  
Janet L. Taylor
Keyword(s):  
Motor Evoked Potentials ◽  
Femoral Nerve ◽  
Silent Period ◽  
Knee Extension ◽  
Voluntary Contraction ◽  
Knee Extensors ◽  
Cortical Input ◽  
Motoneuron Excitability ◽  
Before And After ◽  
Voluntary Contractions

During fatiguing voluntary contractions, the excitability of motoneurons innervating arm muscles decreases. However, the behavior of motoneurons innervating quadriceps muscles is unclear. Findings may be inconsistent because descending cortical input influences motoneuron excitability and confounds measures during exercise. To overcome this limitation, we examined effects of fatigue on quadriceps motoneuron excitability tested during brief pauses in descending cortical drive after transcranial magnetic stimulation (TMS). Participants ( n = 14) performed brief (~5-s) isometric knee extension contractions before and after a 10-min sustained contraction at ~25% maximal electromyogram (EMG) of vastus medialis (VM) on one ( n = 5) or two ( n = 9) days. Electrical stimulation over thoracic spine elicited thoracic motor evoked potentials (TMEP) in quadriceps muscles during ongoing voluntary drive and 100 ms into the silent period following TMS (TMS-TMEP). Femoral nerve stimulation elicited maximal M-waves (Mmax). On the 2 days, either large (~50% Mmax) or small (~15% Mmax) TMS-TMEPs were elicited. During the 10-min contraction, VM EMG was maintained ( P = 0.39), whereas force decreased by 52% (SD 13%) ( P < 0.001). TMEP area remained unchanged ( P = 0.9), whereas large TMS-TMEPs decreased by 49% (SD 28%) ( P = 0.001) and small TMS-TMEPs by 71% (SD 22%) ( P < 0.001). This decline was greater for small TMS-TMEPs ( P = 0.019; n = 9). Therefore, without the influence of descending drive, quadriceps TMS-TMEPs decreased during fatigue. The greater reduction for smaller responses, which tested motoneurons that were most active during the contraction, suggests a mechanism related to repetitive activity contributes to reduced quadriceps motoneuron excitability during fatigue. By contrast, the unchanged TMEP suggests that ongoing drive compensates for altered motoneuron excitability. NEW & NOTEWORTHY We provide evidence that the excitability of quadriceps motoneurons decreases with fatigue. Our results suggest that altered intrinsic properties brought about by repetitive activation of the motoneurons underlie their decreased excitability. Furthermore, we note that testing during voluntary contraction may not reflect the underlying depression of motoneuron excitability because of compensatory changes in ongoing voluntary drive. Thus, this study provides evidence that processes intrinsic to the motoneuron contribute to muscle fatigue of the knee extensors.

Behavior of coactive muscles during fatigue

1993 ◽  
Vol 74 (1) ◽  
pp. 170-175 ◽  
Author(s):  
J. A. Psek ◽  
E. Cafarelli
Keyword(s):  
Time Course ◽  
Vastus Lateralis ◽  
Biceps Femoris ◽  
Close Correlation ◽  
Voluntary Contraction ◽  
Knee Extensors ◽  
Emg Activity ◽  
Short Period ◽  
Force Time ◽  
Knee Flexors

Coactivation is antagonist muscle activity that occurs during voluntary contraction. Recently, we showed that the extent of coactivity in the knee flexors decreases after a short period of resistance training of the knee extensors (8). The purpose of the present experiment was to study the time course of coactivation in the knee flexors during fatigue of the knee extensors. Ten male subjects performed repeated submaximal static leg extensions in a low-intensity long-duration and a high-intensity short-duration fatigue protocol until they could no longer produce the required force [time limit of endurance (Tlim)]. Maximal voluntary contraction (MVC), submaximal force, and surface electromyographic (EMG) activity were measured periodically. Vastus lateralis EMG increased progressively during fatigue of the extensor muscles (P < 0.05), resulting in a 38% change from control at Tlim. Biceps femoris EMG, which was our measure of coactivation, also increased by approximately 60% at Tlim in each protocol (P < 0.05). These observations lead us to conclude that a small but significant force loss during repeated static contractions to Tlim is due to an increase in antagonist activity. Moreover, the close correlation between the antagonist and agonist EMG supports the notion of a "common drive" to both motoneuron pools (10).

Sedentary time is not independently related to postural stability or leg strength in women 50–67 years old

2015 ◽  
Vol 40 (11) ◽  
pp. 1123-1128 ◽  
Author(s):  
Taura Willoughby ◽  
Jennifer L. Copeland
Keyword(s):  
Physical Activity ◽  
Sedentary Behaviour ◽  
Postural Stability ◽  
Muscular Strength ◽  
Sedentary Time ◽  
Peak Torque ◽  
Knee Extensors ◽  
Lower Body ◽  
Wear Time ◽  
Leg Strength

Most research on sedentary behaviour has focused on cardiometabolic outcomes and markers of metabolic dysfunction, while neuromuscular outcomes have received less attention. The objective of the present study was to determine whether sedentary time is negatively associated with laboratory-based measures of lower body muscular strength and postural stability in middle-aged women. Forty-nine women (56.6 ± 4.1 years) participated in the study. Participants wore an ActiGraph GT3X accelerometer for 7 days to quantify sedentary time and physical activity. Following a familiarization session, assessments of lower body muscular strength and postural stability were performed. Peak torque of knee extensors and flexors was assessed using an isokinetic dynamometer. Postural stability was assessed using computerized dynamic posturography and a composite equilibrium score (CES) was calculated. Participants spent 9.4 ± 1.3 h per day (65% of wear time) sedentary and 28.2 ± 17.3 min per day (3.3% of wear time) in moderate to vigorous physical activity (MVPA). Postural stability and relative peak torque of the knee flexors were significantly associated with time spent sedentary (r = –0.35, p = 0.01 and r = –0.31, p = 0.03, respectively). Multiple linear regression analyses showed that after adjusting for MVPA, sedentary time was not significantly related to either CES or peak torque of the knee extensors or flexors. In contrast to our hypothesis, postural stability and leg strength were not independently related to sedentary time. While sedentary behaviour may be an important risk factor for cardiometabolic disease, the present results suggest MVPA may be more important to neuromuscular outcomes.

scholarly journals Exercise-Induced Muscle Damage and Recovery in Young and Middle-Aged Males with Different Resistance Training Experience

Sports ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 132 ◽  
Author(s):  
John Fernandes ◽  
Kevin Lamb ◽  
Craig Twist
Keyword(s):  
Resistance Training ◽  
Muscle Damage ◽  
Peak Power ◽  
Time Course ◽  
Voluntary Contraction ◽  
Voluntary Activation ◽  
Knee Extensors ◽  
Middle Aged ◽  
Training Experience ◽  
Exercise Induced

This study compared the time course of recovery after a squatting exercise in trained young (YG; n = 9; age 22.3 ± 1.7 years) and trained (MT; n = 9; 39.9 ± 6.2 years) and untrained (MU; n = 9; age 44.4 ± 6.3 years) middle-aged males. Before and at 24 and 72 h after 10 × 10 squats at 60% one-repetition maximum (1RM), participants provided measurements of perceived muscle soreness (VAS), creatine kinase (CK), maximal voluntary contraction (MVC), voluntary activation (VA), and resting doublet force of the knee extensors and squatting peak power at 20% and 80% 1RM. When compared to the YG males, the MT experienced likely and very likely moderate decrements in MVC, resting doublet force, and peak power at 20% and 80% 1RM accompanied by unclear differences in VAS, CK, and VA after the squatting exercise. MU males, compared to MT, experienced greater alterations in peak power at 20% and 80% 1RM and VAS. Alterations in CK, MVC, VA, and resting doublet force were unclear at all time-points between the middle-aged groups. Middle-aged males experienced greater symptoms of muscle damage and an impaired recovery profile than young resistance trained males. Moreover, regardless of resistance training experience, middle-aged males are subject to similar symptoms after muscle-damaging lower-body exercise.

Sign in / Sign up

Export Citation Format

Share Document