TABLE 2

Incremental limb-loading characteristics (n=36)

	Healthy (n=13)	Mild ILD (n=10)	Severe ILD (n=13)	p-value
Knee-extensor loading
Peak torque N·m	162±50	137±44	104±32	ns
Protocol length min	12±2	10±3	10±2	ns
Maximal % MVIC achieved	58.5±13	52.5±15	50.0±10	ns
Total work performed J	6328±2515	4911±2211	3368±1330	0.006^#
Start S_pO₂ %	97±1	97±2	98±2	ns
End S_pO₂ %	97±1	95±3	95±4	ns
End HR beats per min	90±12	92±9	101±14	0.03^#
End dyspnoea	1.6±1	1.5±1	3.3±1	0.005^#
End leg fatigue	4±2	3±1	3.5± 1	ns
Elbow-flexor loading
Peak torque N·m	60±19	57±18	40±18	ns
Protocol length min	10.5±1	8.8±2	7.2±2	0.0003^¶
Maximal % MVIC achieved	52.3±7	44.1±11	36.2±10	ns
Total work performed J	3003±1212	2514±911	1446±811	0.001^¶
Start S_pO₂ %	97±2	97±2	98±2	ns
End S_pO₂ %	97±1	96±2	97±2	ns
End HR beats per min	85±11	88±8	94±11	ns
End dyspnoea	1.5±1	1.5±1	3.2±1	0.01^¶
End arm fatigue	4±2	2.5±2	3.5±1	ns

Data are presented as mean±sd unless otherwise stated. ILD: interstitial lung disease; MVIC: maximal voluntary isometric contraction; S_pO₂: arterial oxygen saturation measured by pulse oximetry; HR: heart rate; ns: not significant. ^#: knee-extensor loading: the healthy group had a higher total work than the mild and severe ILD groups; the severe ILD group had a higher end HR and Borg dyspnoea score than the healthy and mild ILD groups. ^¶: elbow-flexor loading: the severe ILD group had a lower protocol length and total work than the mild ILD and healthy groups, and a higher end Borg dyspnoea score.