Simultaneous potentiation and fatigue in quadriceps after a 60-second maximal voluntary isometric contraction

1991 ◽  
Vol 70 (2) ◽  
pp. 726-731 ◽  
Author(s):  
R. W. Grange ◽  
M. E. Houston
Keyword(s):  
Isometric Contraction ◽  
Recovery Period ◽  
Lactate Concentration ◽  
Fold Increase ◽  
Quadriceps Muscle ◽  
Muscle Performance ◽  
Light Chains ◽  
Maximal Voluntary Isometric Contraction ◽  
Muscle Lactate ◽  
Isometric Twitch

Potential mechanisms of fatigue (metabolic factors) and potentiation (phosphate incorporation by myosin phosphorylatable light chains) were investigated during recovery from a 60-s maximal voluntary isometric contraction (MVC) in the quadriceps muscle of 12 subjects. On separate days before and for 2 h after the 60-s MVC, either a 1-s MVC or electrically stimulated contractions were used as indexes to test muscle performance. Torque at the end of the 60-s MVC was 57% of the initial level, whereas torques from a 1-s MVC and 50-Hz stimulation were most depressed in the immediate recovery period. At this time, muscle biopsy analyses revealed significant decreases in ATP and phosphocreatine and a 19-fold increase in muscle lactate. Conversely, isometric twitch torque and torque from a 10-Hz stimulus were the least depressed of six contractile indexes and demonstrated potentiation of 25 and 34%, respectively, by 4 min of recovery (P less than 0.05). At this time, muscle lactate concentration was still 16 times greater than at rest. An increased phosphate content of the myosin phosphorylatable light chains (P less than 0.05) was also evident both immediately and 4 min after the 60-s MVC. We conclude that the 60-s MVC produced marked force decreases likely due to metabolic displacement, while the limited decline in the twitch and 10-Hz torques and their significant potentiation suggested that myosin phosphorylation may provide a mechanism to enhance contractile force under conditions of submaximal activation during fatigue.

Myosin phosphorylation, twitch potentiation, and fatigue in human skeletal muscle

1990 ◽  
Vol 68 (7) ◽  
pp. 908-913 ◽  
Author(s):  
Michael E. Houston ◽  
R. W. Grange
Keyword(s):  
Recovery Period ◽  
Lactate Concentration ◽  
Muscle Metabolism ◽  
Light Chains ◽  
Maximal Voluntary Isometric Contraction ◽  
Myosin Phosphorylation ◽  
Twitch Force ◽  
Twitch Potentiation ◽  
Phosphate Incorporation

Twitch tension and phosphate incorporation into the phosphorylatable light chains (P-light chains) of myosin were studied during a 10-min recovery period following a 10- or 60-s maximal voluntary isometric contraction (MVC) in 18 subjects. Analysis of muscle biopsy samples obtained before, immediately after, 1 min, and 10 min following the 10-s MVC revealed that the 10-s MVC produced a modest but transient metabolic displacement from rest, a 35% decrease in phosphocreatine, and a threefold elevation in lactate concentration. Immediately after the 60-s MVC, ATP was decreased by 20%, phosphocreatine decreased by 84%, and lactate was elevated by 15-fold. Lactate remained elevated over the 10-min recovery period. Twitch force was maximally potentiated following the 10-s MVC and declined to rest by 10 min of recovery. Twitch force was 0.66 of rest value immediately after the 60-s MVC, then increased over the next 4 min to reach a potentiated value 21% greater than rest, before declining. Significant phosphate incorporation into P-light chains was observed immediately after both contractions, but dephosphorylation to rest values at the end of recovery was only noted for the 60-s condition. These results demonstrate an inconsistent relationship between twitch tension enhancement and P-light chain phosphorylation in the in vivo human model.Key words: myosin phosphorylation, human muscle, metabolism, fatigue.

Lactate as substrate for glycogen resynthesis after exercise

1987 ◽  
Vol 62 (6) ◽  
pp. 2237-2240 ◽  
Author(s):  
R. W. Stevenson ◽  
D. R. Mitchell ◽  
G. K. Hendrick ◽  
R. Rainey ◽  
A. D. Cherrington ◽  
...  
Keyword(s):  
Muscle Glycogen ◽  
Recovery Period ◽  
Control Level ◽  
Lactate Concentration ◽  
Perfusion Medium ◽  
Muscle Lactate ◽  
Arterial Lactate ◽  
Medium Flow ◽  
Flow Through ◽  
Lactate Levels

Muscle glycogen levels in the perfused rat hemicorpus preparation were reduced two-thirds by electrical stimulation plus exposure to epinephrine (10(-7) M) for 30 min. During the contraction period muscle lactate concentrations increased from a control level of 3.6 +/- 0.6 to a final value of 24.1 +/- 1.6 mumol/g muscle. To determine whether the lactate that had accumulated in muscle during contraction could be used to resynthesize glycogen, glycogen levels were determined after 1–3 h of recovery from the contraction period during which time the perfusion medium (flow-through system) contained low (1.3 mmol/l) or high (10.5 or 18 mmol/l) lactate concentrations but no glucose. With the low perfusate lactate concentration, muscle lactate levels declined to 7.2 +/- 0.8 mumol/g muscle by 3 h after the contraction period and muscle glycogen levels did not increase (1.28 +/- 0.07 at 3 h vs. 1.35 +/- 0.09 mg glucosyl U/g at end of exercise). Lactate disappearance from muscle was accounted for entirely by output into the venous effluent. With the high perfusate lactate concentrations, muscle lactate levels remained high (13.7 +/- 1.7 and 19.3 +/- 2.0 mumol/g) and glycogen levels increased by 1.11 and 0.86 mg glucosyl U/g, respectively, after 1 h of recovery from exercise. No more glycogen was synthesized when the recovery period was extended. Therefore, it appears that limited resynthesis of glycogen from lactate can occur after the contraction period but only when arterial lactate concentrations are high; otherwise the lactate that builds up in muscle during contraction will diffuse into the bloodstream.

Metabolic intermediates and lactate diffusion in active dog skeletal muscle

1976 ◽  
Vol 231 (3) ◽  
pp. 766-771 ◽  
Author(s):  
TE Graham ◽  
DG Sinclair ◽  
CK Chapler
Keyword(s):  
Skeletal Muscle ◽  
Gastrocnemius Muscle ◽  
Lactate Concentration ◽  
Arterial Occlusion ◽  
Fold Increase ◽  
Major Influence ◽  
Muscle Lactate ◽  
Metabolic Intermediates ◽  
Anesthetized Dogs ◽  
Resting Muscle

The concentration of several metabolic intermediates, blood flow (Q), oxygen uptake (VO2), and lactate release (La) were measured in the gastrocnemius muscle of anesthetized dogs. Muscle lactate concentration increased from 1.6 to 2.7 mumol/g wet wt (P less than 0.05) during 0.5-5 min of contractions at 5 twitches/s but was not different from the contralateral resting muscle at 15, 30, or 60 min. Glycerophosphate increased from 0.35 to 0.70 mumol/g wet wt (P less than 0.05) during 0.5-5 min of activity, whereas muscle pyruvate decreased from 0.09 to 0.07 mumol/g wet wt (P less than 0.05). The concentration of NAD did not change in 9 of 11 experiments during contractions, despite a 12- to 15-fold increase in La. Significant decreases in NAD were observed when Q was compromised by arterial occlusion during contractions. No demonstrable relationship existed between La and either the muscle lactate concentration or muscle-venous lactate concentration gradient. Q was positively correlated with both La and muscle lactate during the first 5-15 min of activity. We conclude that increased La or increased lactate concentration in muscle need not be associated with hypoxia and that Q has a major influence on La.

Effect of endurance training on activators of glycolysis in muscle during exercise

1994 ◽  
Vol 76 (2) ◽  
pp. 846-852 ◽  
Author(s):  
C. Duan ◽  
W. W. Winder
Keyword(s):  
Endurance Training ◽  
Blood Lactate ◽  
Lactate Concentration ◽  
Lactate Production ◽  
Blood Lactate Concentration ◽  
Quadriceps Muscle ◽  
Muscle Lactate ◽  
Cyclic Monophosphate ◽  
Lactate Levels ◽  
Exercise Induced

Endurance training attenuates exercise-induced increases in blood lactate at the same submaximal work rate. Three intramuscular compounds that influence muscle lactate production were measured in fasted non-trained (NT) and endurance-trained (T) rats. The T rats were subjected to a progressive endurance-training program. At the end of the program (11 wk), they were running 2 h/day at 31 m/min up a 15% grade 5 days/wk. NT and T rats were fasted for 24 h and then anesthetized (pentobarbital, iv) at rest or after running for 30 min at 21 m/min (15% grade). Blood lactate levels were significantly lower in the T rats than in the NT rats after 30 min of running (2.3 +/- 0.2 vs. 3.9 +/- 0.2 mM). The lower blood lactate concentration was accompanied by lower plasma epinephrine (2.8 +/- 0.4 vs. 6.0 +/- 0.8 nM), adenosine 3′, 3′,5′-cyclic monophosphate (0.36 +/- 0.02 vs. 0.50 +/- 0.03 pmol/mg), mg), glucose 1,6-diphosphate (26 +/- 2 vs. 40 +/- 5 pmol/mg), and fructose 2,6-diphosphate (3.2 +/- 0.2 vs. 4.3 +/- 0.3 pmol/mg) in white quadriceps muscle in T than in NT rats. Red quadriceps muscle glucose 1,6-diphosphate and adenosine 3′,5′-cyclic monophosphate were also lower in T than in NT rats. These adaptations may be responsible in part for the lower exercise-induced blood lactate in fasted rats as a consequence of endurance training.

Torque potentiation and myosin light-chain phosphorylation in human muscle following a fatiguing contraction

1991 ◽  
Vol 69 (2) ◽  
pp. 269-273 ◽  
Author(s):  
Michael E. Houston ◽  
R. W. Grange
Keyword(s):  
Light Chain ◽  
Human Subjects ◽  
Lactate Concentration ◽  
Human Muscle ◽  
Contractile Element ◽  
Light Chains ◽  
Phosphate Content ◽  
Maximal Voluntary Isometric Contraction ◽  
Muscle Torque ◽  
Isometric Muscle

Indices of electrically stimulated and maximal voluntary isometric muscle torque and the phosphate content of myosin phosphorylatable light chains (P light chains) were studied during recovery following a 60-s maximal voluntary isometric contraction (MVC) in 21 human subjects. Analysis of muscle biopsy samples revealed that immediately after the 60-s MVC there were significant decreases in ATP (−15%) and phosphocreatine (−82%), and lactate concentration increased by 17-fold. All indices of muscle torque production were reduced by the 60-s MVC, but the twitch torque and torque at 10 Hz were relatively less reduced compared with the torque at 20 and 50 Hz or a 1-s MVC. Between 3 and 6 min of recovery, twitch torque and torque at 10 Hz stimulation were significantly potentiated, reaching peak values of 125 and 134%, respectively, compared with rest. Phosphate content of the fast and two slow P light chains was significantly increased over rest levels immediately after and 4 min after the 60-s MVC. These results suggest that myosin P light-chain phosphorylation could provide a mechanism to increase human muscle torque under conditions of submaximal contractile element activation following fatigue.Key words: fatigue, human, muscle, torque, myosin phosphorylation.

Ultrasound Imaging of the Vastus Intermedius and Vastus Medialis Oblique Thickness for Assessment of Early Torque Development During Knee Extension

2020 ◽  
Vol 10 (7) ◽  
pp. 1557-1561
Author(s):  
Jaeho Yang ◽  
Yong Woo An ◽  
Eunwook Chang
Keyword(s):  
Isometric Contraction ◽  
Muscle Thickness ◽  
Peak Torque ◽  
Quadriceps Muscle ◽  
Knee Extension ◽  
Vastus Medialis ◽  
Maximal Voluntary Isometric Contraction ◽  
Rate Of Torque Development ◽  
Vastus Intermedius ◽  
Torque Development

The purpose of this study was to investigate relationships between knee extension torque (rate of torque development and peak torque) and quadriceps muscle thickness in healthy males and females. Thirty-six recreationally active and healthy individuals participated in the study. Portable ultrasound was used to image the dominant side of each quadriceps muscle (rectus femoris, vastus intermedius, vastus lateralis, vastus medialis, vastus medialis oblique). After muscle thickness measurement, participants performed knee extension maximal voluntary isometric contraction. Rate of torque development was calculated from 0 to 50 (RTD50) and 0 to 200 (RTD200) milliseconds after onset of torque generation and peak torque was defined as maximum torque during maximal voluntary isometric contraction trials. A higher RTD50 value was found to be associated with greater vastus intermedius and vastus medialis oblique thicknesses, and a higher RTD200 with the thickness of all quadriceps muscles (p < 0.05). Finally, vastus medialis and vastus medialis oblique thicknesses were associated with a higher peak torque (p < 0.05). According to these results, the findings suggest to coaches that vastus intermedius and vastus medialis oblique thicknesses are critical to torque development during the early phase of knee extension contraction (RTD50), which is essential for executing athletic tasks and preventing injuries.

scholarly journals Eccentrically-Induced Fatigue in Voluntary Muscle Performance: the Effect of Muscle Length and Contraction Type

2018 ◽  
Vol 3 (82) ◽  
Author(s):  
Albertas Skurvydas ◽  
Marius Brazaitis ◽  
Sigitas Kamandulis ◽  
Dalia Mickevičiene ◽  
Diana Karanauskienė
Keyword(s):  
Muscle Fatigue ◽  
Eccentric Exercise ◽  
Isometric Contraction ◽  
Muscle Length ◽  
Quadriceps Muscle ◽  
Muscle Performance ◽  
Significant Difference ◽  
Isokinetic Torque ◽  
Contraction Type ◽  
Torque Development

Research  background  and  hypothesis.  We  hypothesized  that  eccentric  exercise  (EE)  would  induce  muscle fatigue and damage, which are dependent not only on muscle length tested but and on contraction type (eccentric vs. concentric vs. isometric) as well.Research aim was to test the hypothesis.Research methods. Healthy untrained men (mean  ±  SD: age = 24.8  ±  3.7 years, n = 10) performed 10 series of 12 repetitions of eccentric knee contractions at 160 deg/s. The maximal voluntary isometric contraction force (MVC) of the quadriceps muscle, the maximal rate of torque development (RTD) and isokinetic torque at 30 deg/s were established before and after EE. All measures were performed at different knee angles. Besides, the EMG of the quadriceps muscle was measured.Research results showed a significant change in absolute values of RTD after EE (before EE: 3695 ± 803 N∙m/s and 2360 ± 695 N∙m/s at SL and LL respectively; after EE: 2574 ± 843 N∙m/s and 1517 ± 476 N∙m/s at SL and LL respectively). A significant difference between EMG (rms) in MVC was found after EE at LL and SL, i. e. in v.lateralis 0.32 ± 0.12 mV and 0.24 ± 0.1 mV and in r.femoris 0.25 ± 0.11 mV and 0.17 ± 0.07 mV respectively. All criteria of voluntary performance changed significantly after EE except for R TD, i.e. it increased after EE.Discussion and conclusions. We observed more changes in isokinetic torque at shorter muscle length after eccentric exercise-induced muscle fatigue and damage. The changes in MVC and RTD after eccentric exercise did not depend on the length of the muscle tested. Besides, relative RTD did not change after exercise.Keywords: eccentric, concentric and isometric contraction; muscle fatigue and damage; muscle length, muscle force; rate of muscle torque development.

Muscle performance and metabolism in maximal isokinetic cycling at slow and fast speeds

1985 ◽  
Vol 59 (1) ◽  
pp. 132-136 ◽  
Author(s):  
N. L. Jones ◽  
N. McCartney ◽  
T. Graham ◽  
L. L. Spriet ◽  
J. M. Kowalchuk ◽  
...  
Keyword(s):  
Lactate Concentration ◽  
Creatine Phosphate ◽  
Muscle Performance ◽  
Muscle Lactate ◽  
Glycolytic Intermediates ◽  
Before And After ◽  
Exercise Muscle ◽  
Type Of Exercise ◽  
Rate Limiting ◽  
Muscle Biopsies

To provide a description of the metabolic changes in muscle during maximal dynamic exercise, muscle biopsies were obtained in five healthy subjects before and after 30 s of isokinetic exercise at two pedaling frequencies (60 and 140 rpm) associated with contrasting fatigue characteristics. Higher peak power was attained at 140 rpm (1,473 + 185 W) (mean +/- SE) than at 60 rpm (1,122 +/- 70 W), but the decline in power during 30 s (fatigue index) was greater at 140 rpm (61.6 +/- 3.2 vs. 21.5 +/- 2.4%), total work in 30 s being similar (18.1 +/- 1.10 vs. 20.1 +/- 1.10 kJ). Changes in the concentration of muscle metabolites were similar; creatine phosphate concentration fell to approximately 50% of resting values, and the glycolytic intermediates glucose 6-phosphate, fructose 6-phosphate, and fructose 1,6-biphosphate increased up to 30-fold. Muscle lactate concentration ([La-]) was 29.0 +/- 3.98 and 31.0 +/- 4.31 mmol/kg wet wt immediately postexercise at 140 and 60 rpm, respectively. Even after only 10 s exercise (n = 2), large increases were measured in glycolytic intermediates and [La-]. In the two subjects, muscle [La-] increased to 17.2 and 15.1 mmol/kg at 140 rpm and to 14.3 and 14.2 mmol/kg at 60 rpm. In this type of exercise, glycogenolysis is activated very rapidly at both pedal speeds; the changes in glycolytic intermediates were consistent with rate-limiting steps at the phosphofructokinase and pyruvate dehydrogenase reactions. The greater fatigue at the higher speed is not accompanied by different biochemical changes than at 60 rpm.

scholarly journals A novel device for detecting anaerobic threshold using sweat lactate during exercise

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuta Seki ◽  
Daisuke Nakashima ◽  
Yasuyuki Shiraishi ◽  
Toshinobu Ryuzaki ◽  
Hidehiko Ikura ◽  
...  
Keyword(s):  
Lactate Threshold ◽  
Ventilatory Threshold ◽  
Recovery Period ◽  
Lactate Concentration ◽  
Continuous Increase ◽  
Mean Values ◽  
Additional Information ◽  
Novel Device ◽  
Mean Differences ◽  
Lactate Sensor

AbstractThe lactate threshold (LT1), which is defined as the first rise in lactate concentration during incremental exercise, has not been non-invasively and conveniently determined in a clinical setting. We aimed to visualize changes in lactate concentration in sweat during exercise using our wearable lactate sensor and investigate the relationship between the lactate threshold (LT1) and ventilatory threshold (VT1). Twenty-three healthy subjects and 42 patients with cardiovascular diseases (CVDs) were enrolled. During exercise, the dynamic changes in lactate values in sweat were visualized in real-time with a sharp continuous increase up to volitional exhaustion and a gradual decrease during the recovery period. The LT1 in sweat was well correlated with the LT1 in blood and the VT1 (r = 0.92 and 0.71, respectively). In addition, the Bland–Altman plot described no bias between the mean values (mean differences: − 4.5 and 2.5 W, respectively). Continuous monitoring of lactate concentrations during exercise can provide additional information for detecting the VT1.

Which common NIRS variable reflects muscle estimated lactate threshold most closely?

2006 ◽  
Vol 31 (5) ◽  
pp. 612-620 ◽  
Author(s):  
Lixin Wang ◽  
Takahiro Yoshikawa ◽  
Taketaka Hara ◽  
Hayato Nakao ◽  
Takashi Suzuki ◽  
...  
Keyword(s):  
Lactate Threshold ◽  
Near Infrared ◽  
Ventilatory Threshold ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Oxygenation Index ◽  
Muscle Lactate ◽  
Tissue Oxygenation Index ◽  
The Mean ◽  
Tissue Hemoglobin

Various near-infrared spectroscopy (NIRS) variables have been used to estimate muscle lactate threshold (LT), but no study has determined which common NIRS variable best reflects muscle estimated LT. Establishing the inflection point of 2 regression lines for deoxyhaemoglobin (ΔHHbi.p.), oxyhaemoglobin (ΔO2Hbi.p.), and tissue oxygenation index (TOIi.p.), as well as for blood lactate concentration, we then investigated the relationships between NIRS variables and ventilatory threshold (VT), LT, or maximal tissue hemoglobin index (nTHImax) during incremental cycling exercise. ΔHHbi.p. and TOIi.p. could be determined for all 15 subjects, but ΔO2Hbi.p. was determined for only 11 subjects. The mean absolute values for the 2 measurable slopes of the 2 continuous linear regression lines exhibited increased changes in 3 NIRS variables. The workload and VO2 at ΔO2Hbi.p. and nTHImax were greater than those at VT, LT, ΔHHbi.p., and TOIi.p.. For workload and VO2, ΔHHbi.p. was correlated with VT and LT, whereas ΔO2Hbi.p. was correlated with nTHImax, and TOIi.p. with VT and nTHImax. These findings indicate that ΔO2Hb strongly corresponds with local perfusion, and TOI corresponds with both local perfusion and deoxygenation, but that ΔHHb can exactly determine deoxygenation changes and reflect O2 metabolic dynamics. The finding of strongest correlations between ΔHHb and VT or LT indicates that ΔHHb is the best variable for muscle LT estimation.

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