Limitation to exercise performance at altitude – where is peripheral muscle fatigue important?

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.

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

Pediatric Exercise Science ◽

10.1123/pes.22.4.547 ◽

2010 ◽

Vol 22 (4) ◽

pp. 547-556 ◽

Cited By ~ 5

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.

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

Journal of Pain and Symptom Management ◽

10.1016/j.jpainsymman.2014.06.020 ◽

2015 ◽

Vol 49 (2) ◽

pp. 173-182 ◽

Cited By ~ 19

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

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Factors contributing to increased muscle fatigue with β-blockers

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y91-039 ◽

1991 ◽

Vol 69 (2) ◽

pp. 254-261 ◽

Cited By ~ 5

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.

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

Multidisciplinary Respiratory Medicine ◽

10.4081/mrm.2014.372 ◽

2014 ◽

Vol 9 ◽

Cited By ~ 1

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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Mechanism of Dyspnea during Exercise in Children with Corrected Congenital Heart Disease

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph19010099 ◽

2021 ◽

Vol 19 (1) ◽

pp. 99

Author(s):

Mehdi Chlif ◽

Mohamed Mustapha Ammar ◽

Noureddine Ben Said ◽

Levushkin Sergey ◽

Said Ahmaidi ◽

...

Keyword(s):

Congenital Heart Disease ◽

Oxygen Consumption ◽

Heart Disease ◽

Exercise Test ◽

Exercise Performance ◽

Congenital Heart ◽

Isometric Force ◽

Surgical Correction ◽

Time To Exhaustion ◽

Peripheral Muscle

This study will evaluate cardiorespiratory and peripheral muscle function and their relationship with subjective dyspnea threshold after the surgical correction of congenital heart disease in children. Thirteen children with surgically repaired congenital heart disease were recruited. Each participant performed an incremental exercise test on a cycle ergometer until exhaustion. Gas exchanges were continuously sampled to measure the maximal aerobic parameters and ventilatory thresholds. The functional capacity of the subjects was assessed with a 6 min walk test. At the end of the exercise test, isokinetic Cybex Norm was used to evaluate the strength and endurance of the knee extensor muscle in the leg. Dyspnea was subjectively scored with a visual analog scale during the last 15 s of each exercise step. Oxygen consumption measured at the dyspnea score/VO2 relationship located at the dyspnea threshold, at which dyspnea suddenly increased. Results: The maximal and submaximal values of the parameters describing the exercise and the peripheral muscular performances were: VO2 Peak: 33.8 ± 8.9 mL·min−1·kg−1; HR: 174 ± 9 b·min−1; VEmax: 65.68 ± 15.9 L·min−1; P max: 117 ± 27 W; maximal voluntary isometric force MVIF: 120.8 ± 41.9 N/m; and time to exhaustion Tlim: 53 ± 21 s. Oxygen consumption measured at the dyspnea threshold was related to VO2 Peak (R2 = 0.74; p < 0.01), Tlim (R2 = 0.78; p < 0.01), and the distance achieved during the 6MWT (R2 = 0.57; p < 0.05). Compared to the theoretical maximal values for the power output, VO2, and HR, the surgical correction did not repair the exercise performance. After the surgical correction of congenital heart disease, exercise performance was impeded by alterations of the cardiorespiratory function and peripheral local factors. A subjective evaluation of the dyspnea threshold is a reliable criterion that allows the prediction of exercise capacity in subjects suffering from congenital heart disease.

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Effect of peripheral muscle fatigue during the testing of handgrip strength

Fisioterapia em Movimento ◽

10.1590/0103-5150.027.003.ao11 ◽

2014 ◽

Vol 27 (3) ◽

pp. 407-412

Author(s):

Alex de Andrade Fernandes ◽

Ciro José Brito ◽

Breno Cesar Vieira ◽

João Carlos Bouzas Marins

Keyword(s):

Muscle Fatigue ◽

Handgrip Strength ◽

Mean Value ◽

Physical Work ◽

Dominant Hand ◽

Baseline Measure ◽

Peripheral Muscle ◽

Final Sample ◽

Hand Dynamometer ◽

The Mean

Introduction Muscle fatigue is a phenomenon associated with physical work. It is common in endurance sports, physical fitness tests and daily activities. Some tests can be directly affected by the effect of peripheral muscle fatigue, including the handgrip strength (HGS) test, which is considered baseline measure for assessing the functionality of the hand. Objectives a) verify the effect of peripheral muscle fatigue (between trials) during the testing of HGS, with a 60-second recovery interval; b) to analyze whether there is a difference in considering the mean value obtained in three trials or the best result as the final result. Materials and methods The final sample comprised 1,279 men. We followed the standard methodology and used a hydraulic hand dynamometer. Results There were statistically significant differences (P < 0.05) in the dominant hand among all the trials: first (46.5 ± 8.6 Kgf), second (46.4 ± 8.5 Kgf) and third (46.1 ± 8.6 Kgf); and also in the non-dominant hand: first (44.9 ± 8.4 Kgf), second (44.5 ± 8.3 Kgf) and third (44.0 ± 8.3 Kgf). We also found statistically significant differences (P < 0.05) between the two ways of considering the final result. For the dominant hand, the mean of the three attempts was 46.3 ± 8.3 Kgf and the best result was 48.1 ± 8.5 Kgf, whereas for the non-dominant hand, these results were 44.5 ± 8.2 Kgf and 46.0 ± 8.2 kgf, respectively. Conclusion Peripheral muscle fatigue directly interferes in the final result. A significant reduction in strength levels occurs in course of the assessment. The best result is frequently obtained at the first trial, which indicates that the highest value obtained should be considered as the final result.

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