***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Little information is available about the effects of inspiratory muscle training in patients with cystic fibrosis ( CF ) . In this study the effects of inspiratory-threshold loading in patients with CF on strength and endurance of the inspiratory muscles , pulmonary function , exercise capacity , dyspnoea and fatigue were evaluated . Sixteen patients were assigned to one of two groups using the minimization method : eight patients in the training group and eight patients in the control group . The training was performed using an inspiratory-threshold loading device . Patients were instructed to use the threshold trainer 20 min a day , 5 days a week for 6 weeks . Patients in the training group trained at inspiratory threshold loads up to 40 % of maximal static inspiratory pressure ( Pimax ) and patients in the control group got ' sham ' training at a load of 10 % of Pimax . No significant differences were found among the two groups in gender , age , weight , height , pulmonary function , exercise capacity , inspiratory-muscle strength and inspiratory-muscle endurance before starting the training programme . Mean ( SD ) age in the control group was 19 ( 5.5 ) years , mean ( SD ) age in the training group was 17 ( 5.2 ) years .  Mean FEV1 in both groups was 70 % predicted , mean inspiratory-muscle strength in both groups was above 100 % predicted . All patients except one , assigned to the training group , completed the programme . After 6 weeks of training , mean inspiratory-muscle endurance ( % Pimax ) in the control group increased from 50 % to 54 % ( P = 0.197 ) ; in the training group mean inspiratory muscle endurance ( % Pimax ) increased from 49 % to 66 % ( P = 0.003 ) . Statistical analysis showed that the change in inspiratory-muscle endurance ( % Pimax ) in the training group was significantly higher than in the control group ( P = 0.012 ) . After training , in the training group there was a tendency of improvement in Pimax with an increase from 105 to 123 % predicted , which just fell short of statistical significance ( P = 0.064 ) . After training no significant differences were found in changes from baseline in pulmonary function , exercise capacity , dyspnoea and fatigue . It is concluded that low-intensity inspiratory-threshold loading at 40 % of Pimax was sufficient to elicit an increased inspiratory-muscle endurance in patients with CF We examined the effects of ventilatory muscle endurance training on resting breathing pattern in 12 C6-C7 traumatic quadriplegics at least 1 year post-injury . All subjects had complete motor loss below the lesion level . Subjects were r and omly assigned to a training ( N = 6 ) , or a control group ( N = 6 ) . Baseline tests included measurement of resting ventilation and breathing pattern using mercury in rubber strain gauges for 20 minutes in a seated position ; maximum inspiratory mouth pressure ( MIP ) at FRC , and sustainable inspiratory mouth pressure for 10 minutes ( SIP ) ; lung volumes , and arterial blood gases ( ABG 's ) . The training protocol consisted of breathing through an inspiratory resistor equivalent to 85 % SIP for 15 minutes twice daily , 5 days a week for 8 weeks . Both trainers and controls attended the lab every 2 weeks for re assessment of MIP and SIP and the inspiratory resistance was increased in the training group as SIP increased . At the end of 8 weeks , baseline tests were repeated . All subjects had normal ABG 's . There was a significant increase in mean MIP and SIP in both the control group ( 30 % ± 19 % and 31 % ± 18 % respectively ) , and in the training group ( 42 % ± 24 % and 78 % ± 49 % respectively ) . Although the absolute values for both MIP and SIP were greater in the training group than in the control group , the differences were not significant . The alterations in resting breathing pattern were also the same in both groups . Mean frequency decreased significantly in the control group ( 20.2/minute to 16.9/minute ) and , while insignificant , the change in frequency in the training group was the same , 19.4/minute to 16.4/minute . Mean tidal volume ( Vt ) increased 18.2 % of baseline Vt in the control group and 17.0 % baseline in the trainers , result ing in no change in minute ventilation . As MIP and SIP increased similarly in both groups , the data from the control and trainers was pooled and timing changes re-evaluated pre- and post- study . A significant decrease in mean Ti/Ttot was observed , while no change in Vt/ Ti was found . We concluded that the testing procedure itself provided the stimulus result ing in a significant increase in MIP and SIP . The addition of training did not increase MIP and SIP further . The increased MIP and SIP result ed in a slower and deeper breathing pattern and a significantly shorter Ti/Ttot in both trainers and control subjects Whether , and to what extent , beta 2-agonists protect against respiratory muscle overloading and breathlessness during bronchoconstriction remains to be defined in patients with asthma . In a double blind placebo-controlled study , 100 micrograms of fenoterol were administered to six stable asthmatics before a bronchial provocation test , performed by inhaling doubling concentrations of histamine from a Devilbiss 646 nebulizer . We recorded breathing pattern ( tidal volume VT , inspiratory time TI , total time of the respiratory cycle TTOT ) , inspiratory capacity ( IC ) , dynamic pleural pressure swing ( Pplsw ) , total lung resistance ( RL ) and FEV1 . VT was expressed both in actual values and as % of IC . Changes in VT ( % IC ) during histamine inhalation reflected changes in dynamic end-inspiratory lung volume ( EILV ) . Pplsw was expressed as % of maximal ( the most negative in sign ) pleural pressure , obtained under control conditions during a sniff manoeuvre ( Pplsn ) . Pplsw ( % Pplsn ) is an index of inspiratory muscle effort . The test ended when the concentration of histamine which caused a decrease in FEV1 of > or = 40 % post-saline was reached . Dyspnoea rating was scored by a modified Borg scale . At the ultimate degree of bronchoconstriction ( UDB ) with histamine : ( i ) decrease in FEV1 was similar after placebo and fenoterol , while increase in RL was lower after fenoterol ( P < 0.005 ) ; ( ii ) VT(%IC ) increased less after fenoterol ( P < 0.027 ) ; ( iii ) increases in Pplsw ( % Pplsn ) was lower after fenoterol ( P < 0.001 ) ; ( iv ) delta Borg ( from saline ) was lower ( P < 0.01 ) after fenoterol ; ( v ) differences in delta Borg , from placebo to fenoterol , related to concurrent changes in VT(%IC ) ( r2 = 0.67 ) . In conclusion , at UDB 100 micrograms of fenoterol produced a beneficial effect on the degree of inspiratory muscle loading and breathlessness , an effect greater than it would be expected from measuring FEV1 alone BACKGROUND Men and women respond differently to asthma . PATIENTS AND METHODS Maximal inspiratory mouth pressure ( P(Imax ) ) , beta(2)-agonist consumption , and perception of dyspnea ( POD ) were measured in 22 women and 22 men with mild persistent-to-moderate asthma . Next , the women were r and omized into two groups : those who received inspiratory muscle training and those who received sham training . The training ended when the P(Imax ) of the training group was equal to that of the male subjects . POD was then measured once again . RESULTS Baseline P(Imax ) was significantly lower ( p < 0.01 ) while POD and mean daily beta(2)-agonist consumption were significantly higher in the female subjects . P(Imax ) reached the level of the male subjects at the end of the 20th week of training . The increase in the P(Imax ) was associated with a statistically significant decrease in mean daily beta(2)-agonist use and in POD to a similar level as in male subjects . CONCLUSIONS POD and mean daily beta(2)-agonist consumption in asthmatic women are significantly higher , and the P(Imax ) significantly lower , than that of their male counterparts . When the P(Imax ) of female subjects following training is equal to that in male subjects , the differences in POD and mean daily beta(2)-agonist consumption disappear BACKGROUND It is well documented that the perception of dyspnea ( POD ) , subjectively reported by patients , is related to the activity and strength of the inspiratory muscles , and influences the use of ' as needed ' beta2-agonists . STUDY OBJECTIVE To investigate the relationship among the increase in inspiratory muscle strength after specific inspiratory muscle training , beta2-agonist consumption and the POD in patients with persistent , mild to moderate asthma . METHODS Inspiratory muscle strength , daily beta2-agonist consumption and the POD were measured in 30 patients with mild to moderate asthma . Patients were then r and omly assigned to two groups : one group received specific inspiratory muscle training until an increase of more than 20 cm H2O was reached , and one group was a control group and received sham training .  Inspiratory muscle strength , the POD and daily beta2-agonist consumption were assessed during and after the training period . RESULTS There was no good correlation between the baseline maximal inspiratory pressure and the POD , or between the baseline maximal inspiratory pressure and the mean daily beta2-agonist consumption . However , there was a significant correlation between the POD and the mean daily beta2-agonist consumption . The increase in inspiratory muscle strength after the inspiratory muscle training was closely correlated with the decrease in the POD ( P<0.001 ) and the decrease in beta2-agonist consumption ( P<0.001 ) . CONCLUSIONS The present study shows that , in patients with mild to moderate , persistent asthma , there is a correlation between the POD and the mean daily beta2-agonist consumption . When the inspiratory muscles are strengthened , there is a significant decrease in the POD and in beta2-agonist consumption In patients with asthma , the respiratory muscles have to overcome the increased resistance while they become progressively disadvantaged by hyperinflation . We hypothesized that increasing respiratory muscle strength and endurance with specific inspiratory muscle training ( SIMT ) would result in improvement in  asthma symptoms in patients with asthma . Thirty patients with moderate to severe asthma were recruited into 2 groups ; 15 patients received SIMT ( group A ) and 15 patients were assigned to the control group ( group B ) and got sham training in a double-blind group-comparative trial . The training was performed using a threshold inspiratory muscle trainer . Subjects of both groups trained five times a week , each session consisted of 1/2-h training , for six months . Inspiratory muscle strength , as expressed by the PImax at RV , increased significantly , from 84.0 + /- 4.3 to 107.0 + /- 4.8 cm H2O ( p < 0.0001 ) and the respiratory muscle endurance , as expressed by the relationship between Pmpeak and PImax from 67.5 + /- 3.1 percent to 93.1 + /- 1.2 percent ( p < 0.0001 ) , in patients of group A , but not in patients of group B. This improvement was associated with significant improvements compared with baseline for asthma symptoms ( nighttime asthma , p < 0.05 ; morning tightness , p < 0.05 ; daytime asthma , p < 0.01 ; cough , p < 0.005 ) , inhaled B2 usage ( p < 0.05 ) , and the number of hospital ( p < 0.05 ) and sick-leave ( p < 0.05 ) days due to asthma . Five patients were able to stop taking oral/IM corticosteroids while on training and one in the placebo group . We conclude that SIMT , for six months , improves the inspiratory muscle strength and endurance , and results in improvement in asthma symptoms , hospitalizations for asthma , emergency department contact , absence from school or work , and medication consumption in patients with asthma BACKGROUND It has been known for many years that there are variations between asthmatic patients in terms of their perception of breathlessness during airway obstruction . STUDY OBJECTIVE To investigate the relationship between beta(2)-agonist consumption and the score of perception of dyspnea , in mild asthmatics , and the relationship between the effect of specific inspiratory muscle training ( SIMT ) on the score of perception of dyspnea and beta(2)-agonist consumption in " high perceivers . " METHODS Daily beta(2)-agonist consumption was assessed during a 4-week run-in period in 82 patients with mild asthma . Patients with a mean beta(2)-agonist consumption of > 1 puff/d ( " high consumers " ) then were r and omized into two groups : one group of patients received SIMT for 3 months ; the other group of patients was assigned as a control group and received sham training .  Inspiratory muscle strength and perception of dyspnea were assessed before patients entered the study , following the 4-week run-in period , and after completing the training period . RESULTS Following the 4-week run-in period , 23 high-consumer patients ( mean [ + /- SEM ] beta(2)-agonist consumption , 2.7 + /- 0.4 puffs/d ) were detected . The mean Borg score during breathing against resistance was significantly higher ( p < 0.05 ) in the patients with high beta(2)-agonist consumption than in the subjects with low mean beta(2)-agonist consumption . Following SIMT , the mean maximal inspiratory pressure increased significantly from 94.1 + /- 5.1 to 109.7 + /- 5.2 cm H(2)O ( 
    Output:
    
Therefore it is not possible to confirm whether this increase seen with PI(max ) translates into any measurable clinical benefit .
REVIEW ER 'S CONCLUSIONS Currently there is insufficient evidence to suggest that inspiratory muscle training provides any clinical benefit to patients with asthma .