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.
PMID: 11207014 DOI: 10.1053/rmed.2000.0966

STUDY OBJECTIVES: To investigate the effects of high-intensity inspiratory muscle training (IMT) on inspiratory muscle function (IMF), diaphragm thickness, lung function, physical work capacity (PWC), and psychosocial status in patients with cystic fibrosis (CF).
DESIGN: Twenty-nine adult patients with CF were randomly assigned to three groups. Two groups were required to complete an 8-week program of IMT in which the training intensity was set at either 80% of maximal effort (group 1; 9 patients) or 20% of maximal effort (group 2; 10 patients). A third group of patients did not participate in any form of training and acted as a control group (group 3; 10 patients).
INTERVENTIONS: In all patients, baseline and postintervention measures of IMF were determined by maximal inspiratory pressure (Pimax), and sustained Pimax (SPimax); pulmonary function, body composition, and physical activity status were also determined. In addition, diaphragm thickness was measured at functional residual capacity (FRC) and total lung capacity (TLC) [TDIcont], and the diaphragm thickening ratio (TR) was calculated (TR = thickness during Pimax at FRC/mean thickness at FRC). Subjects also completed an incremental cycle ergometer test to exhaustion and two symptom-related questionnaires, prior to and following training.
RESULTS: Following training, significant increases in Pimax and SPimax (p < 0.05), TDIcont (p < 0.05), TR (p < 0.05), vital capacity (p < 0.05), TLC (p < 0.05), and PWC (p < 0.05) were identified, and decreases in anxiety scores (p < 0.05) and depression scores (p < 0.01) were noted in group 1 patients compared to group 3 patients. Group 2 patients significantly improved Pimax and SPimax (both p < 0.05) only with respect to group 3 patients. No significant differences were observed in group 3 patients.
CONCLUSION: An 8-week program of high-intensity IMT resulted in significant benefits for CF patients, which included increased IMF and thickness of the diaphragm (during contraction), improved lung volumes, increased PWC, and improved psychosocial status.

BACKGROUND: Little is known about the opinions or perceived benefits of an inspiratory muscle training intervention in patients with cystic fibrosis and their multidisciplinary team.
OBJECTIVE: The aim of this qualitative study was to examine patients' and multidisciplinary teams' views on inspiratory muscle training to inform and tailor future interventions.
METHODS: Individual, semistructured interviews were conducted to evaluate participants' perspectives of a 4-week inspiratory muscle training intervention. In this study, 8 of 13 individuals involved in the inspiratory muscle training program (5 children aged 11-14 years; 2 physiotherapists; and 1 respiratory physician) participated. Interviews were transcribed verbatim, analyzed using thematic analyses, and then coded into relevant themes.
RESULTS: Four key themes emerged: acceptability, facilitators, barriers, and recommendations. While fun, enjoyment, and improved perceived physical ability were reported by children and their multidisciplinary team following the inspiratory muscle training program, the multidisciplinary team identified factors such as time and cost as key barriers.
CONCLUSIONS: A short inspiratory muscle training program was perceived to have positive effects on the physical ability and psychosocial health of children with cystic fibrosis. These findings highlight the importance of obtaining participants' and multidisciplinary teams' perceptions and recommendations to ensure the efficacy and optimal design of future inspiratory muscle training protocols.
KEYWORDS: cystic fibrosis; health perceptions; inspiratory muscle training; mobile phone; pediatrics; qualitative
PMID: 31518290 PMCID: PMC6715104 DOI: 10.2196/11189

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.
PMID: 1424851 DOI: 10.1378/chest.102.5.1357

Weiner et al. (1992) have reported improvements in lung function, asthma symptoms and reductions in usage of medication following six months of pressure threshold inspiratory muscle training (IMT). Where interventions require compliance with a programme of training, it is important that patients perceive benefits rapidly if compliance is to be maintained. We examined the changes induced by 3 weeks of IMT in mild/moderate asthmatics. Using a single-blind, control design, 18 subjects (10 male) with stable, mild/moderate asthma were randomised to two groups matched for sex and forced vital capacity (FVC). Both groups used a pressure threshold inspiratory muscle trainer (POWERbreathe®). Nine used a protocol which has proven effective in our hands (30 breaths @ ~50% maximum inspiratory pressure (MIP), twice daily), whilst the remainder used a protocol known to be ineffective (60 breaths @ ~20% MIP, twice daily). Lung function, MIP and maximum expiratory pressure (MEP), and exertional dyspnoea were assessed at baseline and after 3 weeks of IMT. Dyspnoea was measured at 1 min intervals during an incremental cycle test to volitional fatigue using a modified Borg scale. A mean Borg score was calculated pre- and post-IMT. Perceptual changes were assessed using a questionnaire. Statistical comparisons were made by repeated measures ANOVA; significance was set at P<0.05. Post-training the IMT group exhibited significant increases in MIP (109 to 121 cmH2O, P<0.004) and peak expiratory flow rate (510 to 551 litres.min-1, P<0.05), as well as a 12.4% reduction in exertional dyspnoea (P<0.006). FVC and forced expiratory volume in 1 sec showed non-significant improvements (4.5% and 8.6%, respectively). The IMT group also reported a significant increase in their motivation to perform exercise (P<0.03). There were no statistically significant changes in the control group. The data are consistent with those of Weiner et al. (1992) and confirm their hypothesis that improvements in MIP and lung function translate into a reduction in exertional dyspnoea. In addition, the data suggest that where appropriate training regimens are used, these changes are observed within 3 weeks of commencement of IMT and lead to an increase in patients’ motivation to take exercise. Reference Weiner et al. (1992). Chest 102 (5): 1357-1361.