Inspiratory muscle training in chronic airflow limitation: comparison of two different training loads with a threshold device

Abstract

I In ns sp pi ir ra at to or ry y m mu us sc cl le e t tr ra ai in ni in ng g i in n c ch hr ro on ni ic c a ai ir rf fl lo ow w l li im mi it ta at ti io on n: : c co om mp pa ar ri is so on n o of f t tw wo o d di if ff fe er re en nt t t tr ra ai in ni in ng g l lo oa ad ds s w wi it th h a a t th hr re es sh ho ol ld ABSTRACT: The usefulness of inspiratory muscle training (IMT) in chronic airflow limitation (CAL) patients is a controversial issue, mainly due to differences in the training load. To further evaluate this aspect, we studied the effect of the magnitude of the load using a threshold pressure trainer.Ten CAL patients (5 males, 5 females), 67±2 yrs (mean±SEM) and forced expiratory volume in one second (FEV 1 ) 36±2% pred, were trained for 30 min a day using a load of 30% of their maximal inspiratory mouth pressure (PImax) (Group 1). Another 10 CAL patients (5 males, 5 females), 73±2 yrs and FEV 1 37±2% pred), were trained using only 12% of their PImax (Group 2). Training was assessed by PImax, inspiratory muscle power output (IMPO), sustainable inspiratory pressure (SIP), maximal inspiratory flow rate (VImax), pattern of breathing during loaded breathing, Mahler's dyspnoea score, and the 6 min walking distance (6MWD).After 5 weeks of training, Group 1 exhibited significant increments in: PImax (34±11%); IMPO (92±16%); SIP (36±9%); and VImax (34±13%). Dyspnoea was also reduced, and the 6MWD increased by 48±22 m. We observed no significant changes in Group 2. During loaded breathing, Group 1 showed a significant increment in tidal volume (VT) and mean inspiratory flow (VT/TI), and a reduction in inspiratory time (TI). In Group 2, VT and VT/TI also increased significantly, but the breathing frequency increased with a reduction of expiratory time. When comparing both groups after training, significant differences in PImax, IMPO, VImax and dyspnoea were observed, with no significant changes in the other parameters.We conclude that, in patients with chronic airflow limitation, inspiratory muscle training with a high enough load improves inspiratory muscle strength and power output, reduces dyspnoea, and makes the pattern of breathing adequate during loaded breathing. These changes may allow patients to cope better with increased loads imposed by physical effort and exacerbation of symptoms.

Role of inspiratory capacity on exercise tolerance in COPD patients with and without tidal expiratory flow limitation at rest

“…Assessment of FL may also provide a useful guide for rehabilitation in COPD patients: in patients without FL, rehabilitation based on exercise should be particularly beneficial, while in patients with FL administration of bronchodilators and inspiratory muscle training should be preferable in order to decrease the prevailing hyperinflation [26,27] and to increase the working capacity of the inspiratory muscles [28,29].…”

Efeitos de programa de exercícios físicos direcionado ao aumento da mobilidade torácica em pacientes portadores de doença pulmonar obstrutiva crônica

“…Apesar da distinção na localização da mobilidade observada no nosso estudo e no de Kakizaki et al, (10) ambos mostram diminuição da dispnéia, efeito este que já foi previamente descrito com o treinamento da endurance muscular e respiratória. (7,8,19,20) Os programas de reabilitação tradicionais (7,8) têm mostrado sucessivamente que o condicionamento físico aeró-bio não modifica a função pulmonar e, conseqüentemente, é amplamente aceito na literatura que a função pulmonar não é alterada pela reabilitação pulmonar. Kakizaki et al (10) mostraram que o alongamento dos músculos respirató-rios da caixa torácica levou a aumento da CVF.…”

Effect of inspiratory muscle training with an intermediate load on inspiratory power output in COPD

“…Using an intermediate resistive load, TZELEPIS et al [3] trained normal subjects and found an increment in both PI,max and V 'I, which is indicative of an improvement in PO. In a previous study we reported an increment in POmax after 5 weeks of IMT with an intermediate inspiratory threshold load in patients with COPD [4]. In the present study, we have also evaluated PO for each of the loads during an incremental threshold loading test, prior to and after IMT with both 10% and 30% PI,max.…”

“…Peak PI,max was measured once a week and PO on two occasions. After this period, the patients in Groups 1 and 2 were assigned by a random and double blind fashion, for training with either 30% or 10% of peak PI,max, according to LARSON et al [5] and to our previous experience [4]. The last level corresponds to the minimal load of the training device.…”

“…We have recently demonstrated that in patients with chronic obstructive pulmonary disease (COPD), IMT using an intermediate threshold load (30% of maximal inspiratory pressure (PI,max)) increases the maximal inspiratory muscle power output (POmax) [4]. Our hypothesis is that this increase in POmax depends on the breathing pattern used for training at a particular load, and hence on the level of flow and pressure developed during the training manoeuvres.…”