Respiratory muscle fatigue was first described in 1977. Inspiratory muscle relaxation rates are known to slow following induction of fatigue. Inspiratory muscle fatigue was induced by threshold loading at 80 percent of (Maximum Inspiratory Pressure) Pimax until the subjects were unable to generate the target pressure. Inspiratory muscle fatigue (IMF) is proposed to negotiation exercise performance, probably via a respiratory muscle metaboreflex that impairs blood flow to working muscles, thereby accelerating the progress of fatigue in these muscles. Respiratory muscle fatigue revealed that a maximal inspiratory load of 50% could quickly fatigue both the inspiration and expiration muscles. Increased inspiratory muscle work may induce fatigue of the respiratory muscles, as well as of the non-respiratory muscles by central alterations at spinal and supraspinal level. Also there is an association between respiratory muscle dysfunction and physical performance in older adults. The abnormalities of respiratory movements may be dependable clinical signs of inspiratory muscle fatigue, mostly when accompanied by tachypnea and hypercapnia. Fatigue is distinguished from weakness, a decrease in force generation that is static and not reversible by rest, though muscle weakness may be a susceptibility to muscle fatigue. This study will contribute to determine the effects of respiratory muscle fatigue on balance and functional mobility with healthy older adults. To further understand this relationship, a battery of tests (considered as gold standard) will be performed after induced inspiratory muscles fatigue.
The aim of study was to evaluate the effects of inspiratory induced muscle fatigue on functional mobility of older adults. Though, limited literature exists regarding inspiratory muscle fatigue and its consequences on functional activities of daily living and balance. Yet, it is not clear how improvement in inspiratory muscle strength is related with improvement in functional mobility.