scholarly journals Severity of arterial hypoxaemia affects the relative contributions of peripheral muscle fatigue to exercise performance in healthy humans

2007 ◽  
Vol 581 (1) ◽  
pp. 389-403 ◽  
Author(s):  
Markus Amann ◽  
Lee M. Romer ◽  
Andrew W. Subudhi ◽  
David F. Pegelow ◽  
Jerome A. Dempsey
Keyword(s):  
Muscle Fatigue ◽  
Exercise Performance ◽  
Healthy Humans ◽  
Peripheral Muscle

Effect of respiratory muscle fatigue on subsequent exercise performance

1991 ◽  
Vol 70 (5) ◽  
pp. 2059-2065 ◽  
Author(s):  
M. J. Mador ◽  
F. A. Acevedo
Keyword(s):  
Oxygen Consumption ◽  
Visual Analogue Scale ◽  
Muscle Fatigue ◽  
Exercise Performance ◽  
Analogue Scale ◽  
Inspiratory Muscle ◽  
Respiratory Effort ◽  
Respiratory Muscle Fatigue ◽  
Subsequent Performance ◽  
Inspiratory Muscle Fatigue

The purpose of this study was to determine whether induction of inspiratory muscle fatigue might impair subsequent exercise performance. Ten healthy subjects cycled to volitional exhaustion at 90% of their maximal capacity. Oxygen consumption, breathing pattern, and a visual analogue scale for respiratory effort were measured. Exercise was performed on three separate occasions, once immediately after induction of fatigue, whereas the other two episodes served as controls. Fatigue was achieved by having the subjects breathe against an inspiratory threshold load while generating 80% of their predetermined maximal mouth pressure until they could no longer reach the target pressure. After induction of fatigue, exercise time was reduced compared with control, 238 +/- 69 vs. 311 +/- 96 (SD) s (P less than 0.001). During the last minute of exercise, oxygen consumption and heart rate were lower after induction of fatigue than during control, 2,234 +/- 472 vs. 2,533 +/- 548 ml/min (P less than 0.002) and 167 +/- 15 vs. 177 +/- 12 beats/min (P less than 0.002). At exercise isotime, minutes ventilation and the visual analogue scale for respiratory effort were larger after induction of fatigue than during control. In addition, at exercise isotime, relative tachypnea was observed after induction of fatigue. We conclude that induction of inspiratory muscle fatigue can impair subsequent performance of high-intensity exercise and alter the pattern of breathing during such exercise.

scholarly journals Does cerebral blood flow & oxygenation limit maximal exercise performance in healthy humans?

2010 ◽  
Vol 24 (S1) ◽  
Author(s):  
Zafeiris Louvaris ◽  
IOANNIS VOGIATZIS ◽  
ATHANASOPOULOS DIMITRIS ◽  
ANDRIANOPOULOS VASILIS ◽  
ALEXOPOULOS PANAGIOTIS ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Exercise Performance ◽  
Maximal Exercise ◽  
Healthy Humans

scholarly journals Acute ibuprofen ingestion does not attenuate fatigue during maximal intermittent knee extensor or all-out cycling exercise

2019 ◽  
Vol 44 (2) ◽  
pp. 208-215 ◽  
Author(s):  
Paul T. Morgan ◽  
Anni Vanhatalo ◽  
Joanna L. Bowtell ◽  
Andrew M. Jones ◽  
Stephen J. Bailey
Keyword(s):  
Exercise Performance ◽  
Power Output ◽  
Knee Extensor ◽  
Cycling Performance ◽  
Similar Rate ◽  
Cycle Ergometer ◽  
Knee Extensors ◽  
Mean Power ◽  
Healthy Humans ◽  
The Mean

Recent research suggests that acute consumption of pharmacological analgesics can improve exercise performance, but the ergogenic potential of ibuprofen (IBP) administration is poorly understood. This study tested the hypothesis that IBP administration would enhance maximal exercise performance. In one study, 13 physically active males completed 60 × 3-s maximal voluntary contractions (MVCs) of the knee extensors interspersed with 2-s passive recovery periods, on 2 occasions, with the critical torque (CT) estimated as the mean torque over the last 12 contractions (part A). In another study, 16 active males completed two 3-min all-out tests against a fixed resistance on an electronically braked cycle ergometer, with the critical power estimated from the mean power output over the final 30 s of the test (part B). All tests were completed 60 min after ingestion of maltodextrin (placebo, PL) or 400 mg of IBP. Peripheral nerve stimulation was administered at regular intervals and electromyography was measured throughout. For part A, mean torque (IBP: 60% ± 13% of pre-exercise MVC; PL: 58% ± 14% of pre-exercise MVC) and CT (IBP: 41% ± 16% of pre-exercise MVC; PL: 40% ± 15% of pre-exercise MVC) were not different between conditions (P > 0.05). For part B, end-test power output (IBP: 292 ± 28 W; PL: 288 ± 31 W) and work done (IBP: 65.9 ± 5.9 kJ; PL: 65.4 ± 6.4 kJ) during the 3-min all-out cycling tests were not different between conditions (all P > 0.05). For both studies, neuromuscular fatigue declined at a similar rate in both conditions (P > 0.05). In conclusion, acute ingestion of 400 mg of IBP does not improve single-leg or maximal cycling performance in healthy humans.

Right Atrial Pacing Increases Maximal Heart Rate But Does Not Alter Vo2Max Or Maximal Exercise Performance In Healthy Humans

2011 ◽  
Vol 43 (Suppl 1) ◽  
pp. 163
Author(s):  
Gregers Munch ◽  
Magnus Christensen ◽  
Niels Secher ◽  
Jesper H. Svendsen ◽  
José González-Alonso ◽  
...  
Keyword(s):  
Heart Rate ◽  
Exercise Performance ◽  
Maximal Exercise ◽  
Right Atrial ◽  
Atrial Pacing ◽  
Maximal Heart Rate ◽  
Healthy Humans

Plyometric Training Does Not Affect Central and Peripheral Muscle Fatigue Differently in Prepubertal Girls and Boys

2010 ◽  
Vol 22 (4) ◽  
pp. 547-556 ◽  
Author(s):  
Albertas Skurvydas ◽  
Marius Brazaitis
Keyword(s):  
Muscle Fatigue ◽  
Central Fatigue ◽  
Quadriceps Muscle ◽  
Voluntary Activation ◽  
Peripheral Fatigue ◽  
Plyometric Training ◽  
Peripheral Muscle ◽  
Before And After ◽  
Voluntary Contractions ◽  
Prepubertal Girls

The aim of the study was to evaluate the effect of plyometric training (PT) on central and peripheral (muscle) fatigue in prepubertal girls and boys. The boys (n = 13, age 10.3 ± 0.3 years) and girls (n = 13, age, 10.2 ± 0.3 years) performed continuous 2-min maximal voluntary contractions (MVCs) before and after 16 high-intensity PT sessions. PT comprised two training sessions per week of 30 jumps in each session with 20 s between jumps. The greatest effect of PT was on excitation–contraction coupling, (twitch force increased by 323% in boys and 21% in girls) and height of a counter–movement jump (increased by 37% in boys and 38% in girls). In contrast, the quadriceps voluntary activation index, central activation ratio, and MVC did not change significantly after PT. The thickness of the quadriceps muscle increased by 9% in boys and 14% in girls after PT. In conclusion, boys and girls demonstrated similar changes in indicators of central fatigue (50–60% decrease) and peripheral fatigue (45–55% decrease) after MVC before and after PT.

scholarly journals The Role of Central and Peripheral Muscle Fatigue in Postcancer Fatigue: A Randomized Controlled Trial

2015 ◽  
Vol 49 (2) ◽  
pp. 173-182 ◽  
Author(s):  
Hetty Prinsen ◽  
Johannes P. van Dijk ◽  
Machiel J. Zwarts ◽  
Jan Willem H. Leer ◽  
Gijs Bleijenberg ◽  
...  
Keyword(s):  
Randomized Controlled Trial ◽  
Muscle Fatigue ◽  
Controlled Trial ◽  
Randomized Controlled ◽  
Peripheral Muscle ◽  
Postcancer Fatigue

Factors contributing to increased muscle fatigue with β-blockers

1991 ◽  
Vol 69 (2) ◽  
pp. 254-261 ◽  
Author(s):  
R. S. McKelvie ◽  
N. L. Jones ◽  
G. I. F. Heigenhauser
Keyword(s):  
Muscle Fatigue ◽  
Exercise Performance ◽  
Cycle Ergometer ◽  
Metabolic Effects ◽  
High Dose ◽  
Exercise Tests ◽  
Significant Difference ◽  
Ergometer Exercise ◽  
The Relationship ◽  
Male Subjects

β-Adrenoceptor blockers are widely used clinically and can be classified as nonselective (β1 and β2) or selective (β1). Impairment of exercise performance is a well-known side effect of this group of drugs. This paper reviews mechanisms that could potentially be responsible for this impairment. In addition to cardiovascular and metabolic effects, β -blockade inhibits Na+–K+ ATPase pumps controlling ion movement between muscle and plasma and thus may contribute to muscle fatigue through this mechanism. To investigate the relationship between the change in plasma [K+] and exercise performance, we studied healthy male subjects taking propranolol. Eight subjects performed maximal incremental cycle ergometer exercise tests during control (no drug), low dose (LD) (40 mg daily), and high dose (HD) (265 ± 4.3 (SE) mg daily) of propranolol. The control plasma [K+] (5.8 ± 0.12 mequiv./L) during exercise was significantly lower than either the LD (6.4 ± 0.05 mequiv./L) or HD (6.1 ± 0.16 mequiv./L) values. There was no significant difference between plasma [K+] for the LD and HD of propranolol. However, maximum oxygen uptake was reduced only while taking the HD of propranolol. Six of the subjects also performed three 30-s bouts of high intensity exercise on an isokinetic cycle ergometer while taking the LD and HD of propranolol. There was no significant difference between doses for the increase in plasma [K+] (LD, 7.8 ± 0.35 mequiv./L vs. HD, 7.6 ± 0.36 mequiv./L) during exercise. However, exercise performance was significantly reduced during HD compared with LD. These results suggest that the increases in plasma [K+] with propranolol did not play a direct significant role in the reduced performance observed during the HD.Key words: exercise, potassium, performance, lactate.

scholarly journals Association between peripheral muscle strength, exercise performance, and physical activity in daily life in patients with Chronic Obstructive Pulmonary Disease

2014 ◽  
Vol 9 ◽  
Author(s):  
Anne-Kathrin Rausch-Osthoff ◽  
Malcolm Kohler ◽  
Noriane A. Sievi ◽  
Christian F. Clarenbach ◽  
Arnoldus J.R. Van Gestel
Keyword(s):  
Physical Activity ◽  
Chronic Obstructive Pulmonary Disease ◽  
Muscle Strength ◽  
Pulmonary Disease ◽  
Exercise Performance ◽  
Daily Life ◽  
Handgrip Strength ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
Peripheral Muscle

Background: Resistance training of peripheral muscles has been recommended in order to increase muscle strength in patients with Chronic Obstructive Pulmonary Disease (COPD). However, whether peripheral muscle strength is associated with exercise performance (EP) and physical activity in daily life (PADL) in these patients needs to be investigated. The aim of this study is to evaluate whether strength of the quadriceps muscle (QS) is associated with EP and daily PADL in patients with COPD. Methods: We studied patients with COPD (GOLD A-D) and measured maximal isometric strength of the left QS. PADL was measured for 7 days with a SenseWear-Pro® accelerometer. EP was quantified by the 6-minute walk distance (6MWD), the number of stands in the Sit-to-Stand Test (STST), and the handgrip-strength. Univariate and multivariate analyses were used to examine possible associations between QS, PADL and EP. Results: In 27 patients with COPD with a mean (SD) FEV1 of 37.6 (17.6)% predicted, QS was associated with 6MWD, STST, and handgrip-strength but not with PADL. Multiple linear regression analyses showed that QS was independently associated with the 6MWD (β = 0.42, 95% CI 0.09 to 0.84, p = 0.019), STST (β = 0.50, 95% CI 0.11 to 0.86, p = 0.014) and with handgrip-strength (β = 0.45, 95% CI 0.05 to 0.84, p = 0.038). Conclusions: Peripheral muscle strength may be associated with exercise performance but not with physical activity in daily life. This may be due to the fact that EP tests evaluate patients’ true abilities while PADL accelerometers may not.

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