Exercise capacity and handgrip strength following dumbbell-assisted diaphragmatic breathing training in patients with bronchiolitis obliterans syndrome after allogeneic hematopoietic stem cell transplantation: a prospective single-arm study

BackgroundBronchiolitis obliterans syndrome (BOS) is a severe complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and is associated with impaired exercise capacity. Feasible rehabilitation strategies for this population remain limited.ObjectivesTo evaluate changes in functional exercise capacity and handgrip strength following a 12-week dumbbell-assisted diaphragmatic breathing training program in patients with BOS after allo-HSCT and to explore associations of these changes with selected baseline characteristics.MethodsThis prospective, single-center, single-arm pre–post interventional study included 31 patients with BOS after allo-HSCT. Participants completed a 12-week dumbbell-assisted diaphragmatic breathing training program. Six-minute walk distance (6MWD) and bilateral handgrip strength were assessed at baseline and week 12. Within-participant changes were evaluated using paired tests according to the distribution of change scores. Associations with selected baseline characteristics were examined in exploratory analyses.ResultsFollowing the 12-week intervention, mean 6MWD increased from 406.3 m at baseline to 425.9 m at week 12, corresponding to a mean within-participant increase of 19.6 m (95% CI: 9.3–29.9 m; p < 0.001). Mean bilateral handgrip strength increased from 23.2 kg to 25.0 kg, corresponding to a mean increase of 1.8 kg (95% CI: 1.3–2.3 kg; p < 0.001). The change in 6MWD did not differ significantly between women and men (p = 0.282), whereas the increase in handgrip strength was greater in women than in men (p = 0.021). Baseline heart-rate response during the 6MWT and supplemental oxygen requirement were not clearly associated with the magnitude of functional change. No serious training-related adverse events were observed.ConclusionsTwelve weeks of dumbbell-assisted diaphragmatic breathing training was associated with improvements in 6MWD and handgrip strength in patients with BOS after allo-HSCT. However, the single-arm design precludes causal attribution of these improvements to the intervention, and the exploratory subgroup findings should be interpreted cautiously. Larger controlled studies are needed to establish efficacy and characterize potential differences in response.