Fatigue and exhaustion in chronic hypobaric hypoxia: influence of exercising muscle mass

1994 ◽  
Vol 76 (2) ◽  
pp. 634-640 ◽  
Author(s):  
B. Kayser ◽  
M. Narici ◽  
T. Binzoni ◽  
B. Grassi ◽  
P. Cerretelli
Keyword(s):  
Hypobaric Hypoxia ◽  
Vastus Lateralis ◽  
Lactate Concentration ◽  
Exercise Bout ◽  
Vastus Lateralis Muscle ◽  
O2 Uptake ◽  
Before And After ◽  
Leg Exercise ◽  
Muscle Groups ◽  
Forearm Exercise

Exhaustive dynamic exercise with large muscle groups in chronic hypobaric hypoxia may be limited by central (nervous) rather than peripheral (metabolic) fatigue. Six males [32 +/- 4 (SD) yr] at sea level (SL) and after 1-mo acclimatization at 5,050 m (HA) performed exhaustive dynamic forearm exercise at a constant absolute load, requiring regional maximum aerobic power at SL, and exhaustive cycle exercise at prevailing maximal O2 uptake (HA approximately equal to 80% SL). Exhaustion time (t(ex)), blood O2 saturation (SaO2), and heart rate (HR) were measured during each exercise bout. Before and after both arm and leg exercise, lactate concentration ([La]), PO2, PCO2, and pH were measured in arterialized blood samples. Integrated electromyogram activity (IEMG) and mean (MPF) and centroid (CPF) power frequencies of the EMG power spectrum during exercise were calculated for forearm flexors and vastus lateralis muscle. t(ex) for forearm exercise at the same absolute load was the same at SL and HA. Similar increases of IEMG (+214% at SL vs. +172% at HA) and decreases of CPF (-13% at SL vs. -16% at HA) and MPF (-22% at SL vs. -21% at HA) were observed. By contrast, at HA, for similar t(ex), leg exercise had to be performed at the same relative (i.e., prevailing maximal O2 uptake) but lower absolute load (approximately equal to 80% of SL).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of previous exercise with arms or legs on metabolism and performance in exhaustive exercise

1975 ◽  
Vol 38 (5) ◽  
pp. 763-767 ◽  
Author(s):  
J. Karlsson ◽  
F. Bonde-Petersen ◽  
J. Henriksson ◽  
H. G. Knuttgen
Keyword(s):  
Blood Lactate ◽  
Vastus Lateralis ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Exercise Bout ◽  
Creatine Phosphate ◽  
The Body ◽  
Exhaustive Exercise ◽  
Leg Exercise ◽  
Muscle Groups

The ability of additional muscles to perform after certain other muscles of the body had been exercised to exhaustion was studied in three male subjects. Exhaustive exercise was performed in two series: series L-A, a bout of leg exercise preceded a bout of arm exercise; series A-L, arm preceded leg (6-min recovery between bouts). Biopsies were taken during the course of each experiment from both the deltoideus and vastus lateralis muscles for determination of ATP, creatine phosphate, lactate, and pyruvate. Exhaustive exercise led to marked elevations in lactate and decreases in ATP and CP in exercised muscle and marked increases in blood lactate concentration. Similar changes, especially in lactate, were observed during and after the first exercise bout in nonexercised muscle. When arm or leg exercise was performed as the second bout, decreases in performance time were observed as compared to performance as the initial bout. It is suggested that the performance potential of muscle is decreased because of internal changes elicited by elevated blood lactate and/or blood H+ concentrations brought about by other muscle groups previously exercised to exhaustion.

Muscle glycogen availability and temperature regulation in humans

1989 ◽  
Vol 66 (1) ◽  
pp. 72-78 ◽  
Author(s):  
L. Martineau ◽  
I. Jacobs
Keyword(s):  
Skeletal Muscle ◽  
Muscle Glycogen ◽  
Temperature Regulation ◽  
Vastus Lateralis ◽  
Water Immersion ◽  
Vastus Lateralis Muscle ◽  
Glycogen Concentration ◽  
Exercise Regimen ◽  
Before And After ◽  
Muscle Groups

The effects of intramuscular glycogen availability on human temperature regulation were studied in eight seminude subjects immersed in 18 degrees C water for 90 min or until rectal temperature (Tre) decreased to 35.5 degrees C. Each subject was immersed three times over a 3-wk period. Each immersion followed 2.5 days of a specific dietary and/or exercise regimen designed to elicit low (L), normal (N), or high (H) glycogen levels in large skeletal muscle groups. Muscle glycogen concentration was determined in biopsies taken from the vastus lateralis muscle before and after each immersion. Intramuscular glycogen concentration before the immersion was significantly different among the L, N, and H trials (P less than 0.01), averaging 247 +/- 15, 406 +/- 23, and 548 +/- 42 (SE) mmol glucose units.kg dry muscle-1, respectively. The calculated metabolic heat production during the first 30 min of immersion was significantly lower during L compared with N or H (P less than 0.05). The rate at which Tre decreased was more rapid during the L immersion than either N or H (P less than 0.05), and the time during the immersion at which Tre first began to decrease also appeared sooner during L than N or H. The results suggest that low skeletal muscle glycogen levels are associated with more rapid body cooling during water immersion in humans. Higher than normal muscle glycogen levels, however, do not increase cold tolerance.

Assessment of cancer prevention effect of exercise

2021 ◽  
pp. 1-6
Author(s):  
Reza Vafaee ◽  
Mostafa Rezaei Tavirani ◽  
Sina Rezaei Tavirani ◽  
Mohammadreza Razzaghi
Keyword(s):  
Gene Expression ◽  
Cancer Prevention ◽  
Human Health ◽  
Expression Profiles ◽  
Vastus Lateralis ◽  
Gene Expression Profiles ◽  
Gene Expression Omnibus ◽  
Vastus Lateralis Muscle ◽  
Before And After ◽  
Exercise Training Intervention

There are many documents about benefits of exercise on human health. However, evidences indicate to positive effect of exercise on disease prevention, understanding of many aspects of this mechanism need more investigations. Determination of critical genes which effect human health. GSE156249 including 12 gene expression profiles of healthy individual biopsy from vastus lateralis muscle before and after 12-week combined exercise training intervention were extracted from gene expression omnibus (GEO) database. The significant DEGs were included in interactome unit by Cytoscape software and STRING database. The network was analyzed to find the central nodes subnetwork clusters. The nodes of prominent cluster were assessed via gene ontology by using ClueGO. Number of 8 significant DEGs and 100 first neighbors analyzed via network analysis. The network includes 2 clusters and COL3A1, BGN, and LOX were determined as central DEGs. The critical DEGs were involved in cancer prevention process.

Enhanced sarcoplasmic reticulum Ca2+ release following intermittent sprint training

2000 ◽  
Vol 279 (1) ◽  
pp. R152-R160 ◽  
Author(s):  
Niels Ørtenblad ◽  
Per K. Lunde ◽  
Klaus Levin ◽  
Jesper L. Andersen ◽  
Preben K. Pedersen
Keyword(s):  
Sarcoplasmic Reticulum ◽  
High Intensity ◽  
Vastus Lateralis ◽  
Ryanodine Receptors ◽  
Vastus Lateralis Muscle ◽  
Sprint Training ◽  
High Intensity Training ◽  
Before And After ◽  
Muscle Biopsies ◽  
Intensity Training

To evaluate the effect of intermittent sprint training on sarcoplasmic reticulum (SR) function, nine young men performed a 5 wk high-intensity intermittent bicycle training, and six served as controls. SR function was evaluated from resting vastus lateralis muscle biopsies, before and after the training period. Intermittent sprint performance (ten 8-s all-out periods alternating with 32-s recovery) was enhanced 12% ( P < 0.01) after training. The 5-wk sprint training induced a significantly higher ( P < 0.05) peak rate of AgNO3-stimulated Ca2+ release from 709 (range 560–877; before) to 774 (596–977) arbitrary units Ca2+ ⋅ g protein− 1 ⋅ min− 1(after). The relative SR density of functional ryanodine receptors (RyR) remained unchanged after training; there was, however, a 48% ( P < 0.05) increase in total number of RyR. No significant differences in Ca2+ uptake rate and Ca2+-ATPase capacity were observed following the training, despite that the relative density of Ca2+-ATPase isoforms SERCA1 and SERCA2 had increased 41% and 55%, respectively ( P < 0.05). These data suggest that high-intensity training induces an enhanced peak SR Ca2+ release, due to an enhanced total volume of SR, whereas SR Ca2+ sequestration function is not altered.

scholarly journals A Novel Method for Classification of Running Fatigue Using Change-Point Segmentation

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4729 ◽  
Author(s):  
Taha Khan ◽  
Lina E. Lundgren ◽  
Eric Järpe ◽  
M. Charlotte Olsson ◽  
Pelle Viberg
Keyword(s):  
Random Forest ◽  
Blood Lactate ◽  
Change Point ◽  
Vastus Lateralis ◽  
Lactate Concentration ◽  
Treadmill Running ◽  
Vastus Lateralis Muscle ◽  
Semg Signal ◽  
Novel Method

Blood lactate accumulation is a crucial fatigue indicator during sports training. Previous studies have predicted cycling fatigue using surface-electromyography (sEMG) to non-invasively estimate lactate concentration in blood. This study used sEMG to predict muscle fatigue while running and proposes a novel method for the automatic classification of running fatigue based on sEMG. Data were acquired from 12 runners during an incremental treadmill running-test using sEMG sensors placed on the vastus-lateralis, vastus-medialis, biceps-femoris, semitendinosus, and gastrocnemius muscles of the right and left legs. Blood lactate samples of each runner were collected every two minutes during the test. A change-point segmentation algorithm labeled each sample with a class of fatigue level as (1) aerobic, (2) anaerobic, or (3) recovery. Three separate random forest models were trained to classify fatigue using 36 frequency, 51 time-domain, and 36 time-event sEMG features. The models were optimized using a forward sequential feature elimination algorithm. Results showed that the random forest trained using distributive power frequency of the sEMG signal of the vastus-lateralis muscle alone could classify fatigue with high accuracy. Importantly for this feature, group-mean ranks were significantly different (p < 0.01) between fatigue classes. Findings support using this model for monitoring fatigue levels during running.

scholarly journals Effect of tapering after a period of high-volume sprint interval training on running performance and muscular adaptations in moderately trained runners

2018 ◽  
Vol 124 (2) ◽  
pp. 259-267 ◽  
Author(s):  
Casper Skovgaard ◽  
Nicki Winfield Almquist ◽  
Thue Kvorning ◽  
Peter Møller Christensen ◽  
Jens Bangsbo
Keyword(s):  
Oxygen Uptake ◽  
Short Duration ◽  
Vastus Lateralis ◽  
Interval Training ◽  
High Volume ◽  
Running Economy ◽  
Vastus Lateralis Muscle ◽  
Sprint Interval Training ◽  
Before And After ◽  
Trained Runners

The effect of tapering following a period of high-volume sprint interval training (SIT) and a basic volume of aerobic training on performance and muscle adaptations in moderately trained runners was examined. Eleven (8 men, 3 women) runners [maximum oxygen uptake (V̇o2max): 56.8 ± 2.9 ml·min−1·kg−1; mean ± SD] conducted high-volume SIT (HV; 20 SIT sessions; 8–12 × 30 s all-out) for 40 days followed by 18 days of tapering (TAP; 4 SIT sessions; 4 × 30 s all-out). Before and after HV as well as midway through and at the end of TAP, the subjects completed a 10-km running test and a repeated running test at 90% of vV̇o2max to exhaustion (RRT). In addition, a biopsy from the vastus lateralis muscle was obtained at rest. Performance during RRT was better ( P < 0.01) at the end of TAP than before HV (6.8 ± 0.5 vs. 5.6 ± 0.5 min; means ± SE), and 10-km performance was 2.7% better ( P < 0.05) midway through (40.7 ± 0.7 min) and at the end of (40.7 ± 0.6 min) TAP than after HV (41.8 ± 0.9 min). The expression of muscle Na+-K+-ATPase (NKA)α1, NKAβ1, phospholemman (FXYD1), and sarcoplasmic reticulum calcium transport ATPase (SERCA1) increased ( P < 0.05) during HV and remained higher during TAP. In addition, oxygen uptake at 60% of vV̇o2max was lower ( P < 0.05) at the end of TAP than before and after HV. Thus short-duration exercise capacity and running economy were better than before the HV period together with higher expression of muscle proteins related to Na+/K+ transport and Ca2+ reuptake, while 10-km performance was not significantly improved by the combination of HV and tapering. NEW & NOTEWORTHY Short-duration performance became better after 18 days of tapering from ~6 wk of high-volume sprint interval training (SIT), whereas 10-km performance was not significantly affected by the combination of high-volume SIT and tapering. Higher expression of muscle NKAα1, NKAβ1, FXYD1, and SERCA1 may reflect faster Na+/K+ transport and Ca2+ reuptake that could explain the better short-duration performance. These results suggest that the type of competition should determine the duration of tapering to optimize performance.

Carbohydrate Supplementation Attenuates Muscle Glycogen Loss during Acute Bouts of Resistance Exercise

2000 ◽  
Vol 10 (3) ◽  
pp. 326-339 ◽  
Author(s):  
G. Gregory Haff ◽  
Alexander J. Koch ◽  
Jeffrey A. Potteiger ◽  
Karen E. Kuphal ◽  
Lawrence M. Magee ◽  
...  
Keyword(s):  
Resistance Exercise ◽  
Body Mass ◽  
Muscle Glycogen ◽  
Vastus Lateralis ◽  
Placebo Treatment ◽  
Double Blind ◽  
Isokinetic Test ◽  
Before And After ◽  
Leg Exercise ◽  
Wet Weight

The effects of carbohydrate (CHO) supplementation on muscle glycogen and resistance exercise performance were examined with eight highly resistance trained males (mean ± SEM, age: 24.3 ± 1.1 years, height: 171.9±2.0 cm, body mass: 85.7 ± 3.5 kg; experience 9.9 ± 2.0 years). Subjects participated in a randomized, double blind protocol with testing sessions separated by 7 days. Testing consisted of an initial isokinetic leg exercise before and after an isotonic resistance exercise (IRT) session consisting of 3 leg exercises lasting ~39 min. Subjects consumed a CHO (1.0 g CHO ·kg body mass−1) or placebo treatment (PLC), prior to and every 10-min (0.5 g CHO ·kg body mass−1) during the IRT. Muscle tissue was obtained from the m vastus lateralis after a supine rest (REST) immediately after the initial isokinetic test (POST-ISO) and immediately after the IRT (POST-IRT). The CHO treatment elicited significantly less muscle glycogen degradation from the POST-ISO to POST-IRT (126.9 ± 6.5 to 109.7 ± 7.1 mmol·kg wet weight−1) compared to PLC (121.4±8.1 to 88.3±6.0 mmol·kg wet weight−1). There were no differences in isokinetic performance between the treatments. The results of this investigation indicate that the consumption of a CHO beverage can attenuate the decrease in muscle glycogen associated with isotonic resistance exercise but does not enhance the performance of isokinetic leg exercise.

Association Between Deoxygenated Hemoglobin Breaking Point, Anaerobic Threshold, and Rowing Performance

2019 ◽  
Vol 14 (8) ◽  
pp. 1103-1109
Author(s):  
Tiago Turnes ◽  
Rafael Penteado dos Santos ◽  
Rafael Alves de Aguiar ◽  
Thiago Loch ◽  
Leonardo Trevisol Possamai ◽  
...  
Keyword(s):  
Heart Rate ◽  
Anaerobic Threshold ◽  
Power Output ◽  
Vastus Lateralis ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Breaking Point ◽  
Vastus Lateralis Muscle ◽  
Incremental Test ◽  
Deoxygenated Hemoglobin

Purpose: To compare the intensity and physiological responses of deoxygenated hemoglobin breaking point ([HHb]BP) and anaerobic threshold (AnT) during an incremental test and to verify their association with 2000-m rowing-ergometer performance in well-trained rowers. Methods: A total of 13 male rowers (mean [SD] age = 24 [11] y and  = 63.7 [6.1] mL·kg−1·min−1) performed a step incremental test. Gas exchange, vastus lateralis [HHb], and blood lactate concentration were measured. Power output, , and heart rate of [HHb]BP and AnT were determined and compared with each other. A 2000-m test was performed in another visit. Results: No differences were found between [HHb]BP and AnT in the power output (236 [31] vs 234 [31] W; Δ = 0.7%), 95% confidence interval [CI] 6.7%), (4.2 [0.5] vs 4.3 [0.4] L·min−1; Δ = −0.8%, 95% CI 4.0%), or heart rate (180 [16] vs 182 [12] beats·min−1; Δ = −1.6%, 95% CI 2.1%); however, there was high typical error of estimate (TEE) and wide 95% limits of agreement (LoA) for power output (TEE 10.7%, LoA 54.1–50.6 W), (TEE 5.9%, LoA −0.57 to 0.63 L·min−1), and heart rate (TEE 2.4%, LoA −9.6 to 14.7 beats·min−1). Significant correlations were observed between [HHb]BP (r = .70) and AnT (r = .89) with 2000-m mean power. Conclusions: These results demonstrate a breaking point in [HHb] of the vastus lateralis muscle during the incremental test that is capable of distinguishing rowers with different performance levels. However, the high random error would compromise the use of [HHb]BP for training and testing in rowing.

Sparing effect of chronic high-altitude exposure on muscle glycogen utilization

1982 ◽  
Vol 52 (4) ◽  
pp. 857-862 ◽  
Author(s):  
A. J. Young ◽  
W. J. Evans ◽  
A. Cymerman ◽  
K. B. Pandolf ◽  
J. J. Knapik ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Free Fatty Acids ◽  
High Altitude ◽  
Muscle Glycogen ◽  
Vastus Lateralis ◽  
Venous Blood ◽  
Vastus Lateralis Muscle ◽  
Before And After ◽  
Glycogen Utilization ◽  
Sparing Effect

Substrate utilization during heavy [approximately 85% maximum O2 consumption (VO2max)] bicycle exercise was examined in eight low-altitude residents at sea level (SL) and after acute (2 h) and chronic (18 days) high-altitude (HA) exposure at 4,300 m. Mean VO2max was approximately 27% lower at acute HA than at SL and did not change significantly with continued HA exposure. Biopsies from the vastus lateralis muscle and venous blood samples were obtained before and after 30 min of exercise, whereas determinations of the respiratory exchange ratio (R) were made at 10-min intervals during each of the submaximal bouts. Resting levels of serum-free fatty acids at acute and chronic HA were, respectively, two and three times higher than SL but were unchanged with exercise. Exercise did not alter resting serum glycerol levels at SL or during acute HA, but during chronic HA resting glycerol levels were increased 11-fold. Although mean blood lactate concentrations following exercise at SL and acute HA were not significantly different, postexercise lactate concentrations were 87% lower after chronic HA. During exercise at SL and acute HA, muscle glycogen utilization and R were not different. At chronic HA, muscle glycogen utilization and R were 41 and 15% lower, respectively. These data suggest that after chronic HA exposure, increased mobilization and use of free fatty acids during exercise resulted in sparing of muscle glycogen.

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