Characteristics of included studies
| Study | Population | Exercise training | Rehabilitation program | Outcomes |
| Anardottir8 | 60 patients with COPD (15% male, mean FEV1 33% predicted, mean age 65 years) | I: cycling at ≥80% of Ppeak (3 min) and 30–40% of Ppeak (3 min). C: cycling at ≥65% of Ppeak | Sessions of 39 min, 2×/week for 16 weeks; breathing exercises, relaxation exercises, resistance training | IET, endurance exercise test, 12MWT, CRQ, SF-36, HAD |
| Coppoolse9 | 21 male patients with COPD (mean FEV1 37% predicted, mean age 65 years) | I: cycling at 90% of Ppeak (1 min) and 45% of Ppeak (2 min) 3 days/week plus continuous cycling at 60% of Ppeak 2 days/week. C: cycling at 60% of Ppeak | Sessions of 30 min, 5×/week for 8 weeks; education, relaxation exercises, physiotherapy | IET, CWR |
| Mador10 | 41 patients with COPD (mean FEV1 45% predicted, mean age 72 years) | I: cycling or treadmill at 150% of continuous target for 1 min and 75% of target for 2 min. C: cycling at 50% Ppeak and at 80% of 6MWT average speed on treadmill | Sessions of 20–40 min, 3×/week for 8 weeks; education, calisthenics | IET, 6MWT, CWR, CRQ, quadriceps fatigability |
| Nasis20 | 42 patients with COPD (79% male, mean FEV1 42% predicted, mean age 66 years) | I: cycling at 100% Ppeak (30 s) and 45% of Ppeak (30 s) for 40 min; MTI 126±4% of Ppeak; mean dyspnoea 3.0±0.4; mean leg discomfort 2.9±0.5. C: cycling at≥60% Ppeak for 30 min; MTI 76±5% of Ppeak; mean dyspnoea 3.5±0.4; mean leg discomfort 3.5±0.5 | Sessions of 30–40 min, 3×/week for 10 weeks; education, breathing exercises | IET, 6MWT, BODE index |
| Puhan11 | 98 patients with COPD (66% male, mean FEV1 34% predicted, mean age 69 years) | I: cycling at 50% of Ppeak on steep-ramp test* (20 s) and 10% of Ppeak (40 s); mean dyspnoea after 20 min 3.6±1.0. C: cycling at ≥70% of Ppeak; mean dyspnoea after 20 min 3.6±1.3 | Sessions of 25 min, 5×/week, for 3 weeks; breathing exercises, education, relaxation exercises | CRQ, HAD, 6MWT, unintended breaks, IET |
| Varga13 | 71 patients with COPD (78% male, mean FEV1 55% predicted, mean age 64 years) | I: cycling at 90% of Ppeak (2 min) and 50% of Ppeak (1 min) for 30 min with 7.5 min warm-up/cool down at 50% of Ppeak; MTI 161.6±50.6kJ. C: 80% of Ppeak; MTI 199.8±74.8 kJ† | Sessions of 45 min, 3×/week for 8 weeks | IET, activity questionnaire |
| Vogiatzis15 | 36 patients with COPD (83% male, mean FEV1 45% predicted, mean age 68 years) | I: cycling at 100% Ppeak (30 s) and 45% of Ppeak (30 s) weeks 1–4, at 120% weeks 5–8 and at 140% weeks 9–12; MTI 124±3% Ppeak. C: cycling at 50% Ppeak weeks 1–4, at 60% weeks 5–8 and at 70% weeks 9–12; MTI 67±1% Ppeak | Sessions of 40 min, 2×/week for 12 weeks; education, breathing exercises, psychological support, relaxation exercises | IET, CRQ |
| Vogiatzis16 | 19 patients with COPD (84% male, mean FEV1 40% predicted, mean age 66 years) | I: 100% of Ppeak (30 s) and 45% of Ppeak (30 s) weeks 1–3, at 120% weeks 4–6 and at 140% weeks 7–10; MTI 124±15% Ppeak; mean dyspnoea 73±9%; mean leg fatigue 60±8%. C: cycling at 60% of Ppeak weeks 1–3, at 70% weeks 4–6 and at 80% weeks 7–10; MTI 75±5% Ppeak; mean dyspnoea 83±10%; mean leg fatigue 87±13% | Sessions of 45 min, 3×/week for 10 weeks; breathing exercises, education, psychological support, relaxation exercises | Muscle biopsies, IET |
C, continuous training group; COPD, chronic obstructive respiratory disease; CRQ, Chronic Respiratory Questionnaire; CWR, constant work rate test; FEV1, forced expiratory volume in 1 s; HAD, Hospital Anxiety and Depression scale; I, interval training group; IET, incremental exercise test; MTI, mean training intensity; Ppeak, peak exercise capacity; SF-36, Short Form-36.
↵* 50% of peak exercise capacity determined by a steep ramp test corresponds to 90–100% of normal maximum exercise capacity.
↵† Also included a self-paced group.