Effect Of Inspiratory Muscle Work On Peripheral Fatigue Of Locomotor Muscles In Healthy Humans

“The work of breathing required during maximal exercise compromises blood flow to limb locomotor muscles and reduces exercise performance. This study asked if force output of the inspiratory muscles affected exercise-induced peripheral fatigue of locomotor muscles.”

Conclusion:

“Peripheral fatigue of locomotor muscles resulting from high-intensity sustained exercise is, in part, due to the accompanying high levels of respiratory muscle work.”

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The Influence Of Inspiratory Muscle Work History And Specific IMT Upon Human Limb Muscle Fatigue

“The purpose of this study was to assess the influence of the work history of the inspiratory muscles upon the fatigue characteristics of the plantar flexors. It was hypothesized that under conditions where the inspiratory muscle metaboreflex has been elicited, plantar flexors fatigue would be hastened due to peripheral vasoconstriction.”

Conclusion:

“The data are the first to provide evidence that the inspiratory muscle metaboreflex accelerates the rate of calf fatigue during plantar flexors, and that inspiratory muscle training attenuates this effect.”

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Repeated Abdominal Exercise Induces Respiratory Muscle Fatigue

“Prolonged bouts of hyperpnea or resisted breathing are known to result in respiratory muscle fatigue, as are primarily non respiratory exercises such as maximal running and cycling… Sit-up training has been used to increase respiratory muscle strength, but no studies have been done to determine whether this type of non-respiratory activity can lead to respiratory fatigue. The purpose of the study was to test the effect of sit-ups on various respiratory muscle strength and endurance parameters.”

Conclusion:

“After a one-time fatiguing sit-up exercise bout there is a reduction in respiratory muscle strength (MIP, MEP) and endurance (incremental breathing test duration) but not spirometric pulmonary function.”

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Changes In Respiratory Muscle And Lung Function Following Marathon Running In Man

“Respiratory muscle fatigue has been reported following short bouts of high-intensity exercise, and prolonged, moderate-intensity exercise… However, links to functionally relevant outcomes such as breathing effort have been lacking. This study examined dyspnoea and leg fatigue during a treadmill marathon in nine experienced runners.”

Conclusion:

“Results confirm that prolonged moderate-intensity exercise induces inspiratory muscle fatigue. Furthermore, they suggest that the relative intensity of inspiratory muscle work during exercise makes some contribution to leg fatigue.”

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Respiratory Muscle Training Improves Swimming Endurance In Divers

“The purpose of this study was to determine if two different respiratory muscle training (RRMT) protocols enhance respiratory function and swimming performance in divers.”

Conclusion:

“Results indicated that respiratory muscle fatigue is a limiting factor for underwater swimming performance, and that targeted respiratory muscle training (RRMT > ERMT (endurance)) improves respiratory muscle and underwater swimming performance.”

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Resistive Respiratory Muscle Training Improves And Maintains Endurance Swimming Performance In Divers

“In comparison to exercise on land, respiratory work during underwater exercise is increased due to the hydrostatic pressure differences across the chest as well as increased flow resistive respiratory work.”

“It has recently been shown in healthy individuals that ventilatory limitations may cause a reduction of maximal exercise performance on land. The weakened exercise capacity has been attributed to a reduction in locomotor muscle oxygen transport secondary to diminished locomotor muscle blood flow. In several studies on land, respiratory muscle fatigue has been reported as a contributing factor to reduced maximal and endurance exercise performance. These same factors may also limit exercise performance in divers.

Conclusion:

“The major findings of the present study were that 30 minutes of resistance respiratory muscle training carried out three or five days per week for four weeks substantially improved fin swimming endurance (at 70-75%V. O ) and that similar improvements in respiratory muscle performance were obtained.”

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Occurrence of Core Muscle Fatigue During High-Intensity Running Exercise and its Limitation to Performance

“The purpose of this study was to investigate the occurrence of core muscle fatigue during high-intensity running exercise and its limitation to exercise performance. A secondary aim was to investigate whether respiratory muscle work performed during intense running periods, would contribute to core muscle fatigue.”

Conclusion:

“Core muscle function in endurance runners subsequent to intense running to exhaustion was impaired with fatigue. With the preceded core muscle fatigue workout, the endurance capacity for performing intense running was reduced. In mimicking the respiratory responses recorded during intense running while the runners were standing upright and free from whole-body exercise, core muscle function decreased.

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Inspiratory Muscle Training Attenuates The Human Respiratory Muscle Metaboreflex

“Researchers of this study hypothesized that inspiratory muscle training (IMT) would attenuate the sympathetically mediated heart rate and mean arterial pressure increases normally observed during fatiguing inspiratory muscle work.”

Conclusion:

“Findings demonstrate that 5 weeks of resistive inspiratory muscle training is capable of increasing inspiratory muscle strength and attenuating the time-dependent rise in mediated heart rate and mean arterial pressure that occurs with resistive inspiratory work in healthy males.”

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Development Of Respiratory Muscle Contractile Fatigue In The Course Of Hyperpnoea

“This study assessed the development of inspiratory and expiratory muscle fatigue during normocapnic hyperpnoea.”

Conclusion:

“During hyperpnoea, contractile fatigue of the diaphragm and abdominal muscles develops long before task failure and may trigger an increased recruitment of rib cage muscles.”

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Respiratory Muscle Training in Healthy Humans: Resolving the Controversy

“An overview of the literature that rationalizes contradictory findings about respiratory muscle training in healthy people.”

Conclusion:

“It is likely that the ergogenic effect of respiratory muscle training (RMT) has a multifactorial etiology that may include:

  1. The direct effect of RMT upon respiratory muscle fatigue
  2. RMT’s indirect effects upon improving blood flow distribution to limb locomotor muscles in heavy exercise
  3. RMT’s direct and indirect effect upon the intensity with which both respiratory and peripheral efforts are perceived.”

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