Overall results of the meta-analysis using the fixed effect model
| Outcome measure | Studies n | Weighted averaged effect-size | Natural units | 95% CI | Z-statistic | Homogeneity Q-statistic | Studies needed# n |
| Inspiratory muscle strength PI,max | 15 | 0.56 | 10.5 cmH2O | 0.35–0.77 | 5.27* | 16.83 | ≥77 |
| Inspiratory muscle endurance MVV | 4 | 0.21 | 2.8 L·min−1 | −0.29–0.70 | 0.82 | 1.38 | |
| Inspiratory muscle endurance s | 7 | 0.41 | 154.2 s | 0.14–0.68 | 2.94** | 6.67 | ≥14 |
| Inspiratory muscle endurance cmH2O | 4 | 1.16 | 10.3 cmH2O | 0.67–0.15 | 4.67* | 5.39 | ≥10 |
| Functional exercise capacity 6- or 12MWD | 8 | 0.22 | 48.1 m | −0.05–0.48 | 1.58 | 2.58 | |
| Laboratory exercise capacity V′O2,max | 5 | 0.04 | −0.04 L·min−1 | −0.36–0.29 | −0.24 | 2.50 | |
| Laboratory Exercise capacity V′E,max | 5 | 0.03 | −1.5 L·min−1 | −0.03–0.35 | 0.16 | 5.49 | |
| Dyspnea-Borg exercise-related | 5 | −0.55 | −1.5 | −0.90–0.19 | −3.10** | 3.69 | ≥10 |
| Dyspnoea-TDI rest | 2 | 2.3 | 2.7 | 1.44–3.15 | 5.28** | 4.14 | ≥14 |
CI: confidence interval
PI,max: maximum static inspiratory alveolar pressure
MVV: maximal voluntary ventilation
6- or 12MWD: 6- or 12-min walking distance
V′O2,max: maximal oxygen consumption
V′E,max: maximal minute ventilation
TDI: transitional dyspnoea index
#: studies needed for p>0.05
**: p<0.01
***: p<0.001