Table 2 Comparison of mean (SD) EMG activity, burst duration (ms), and burst onset pre‐cough (ms) between reflex cough and the comparable quintile of voluntary cough flow rate.
| Voluntary cough | Reflex cough (R1) | Reflex cough (R2) | p value | |
|---|---|---|---|---|
| Normalised EMG activity | ||||
| Rectus abdominis | 68.2 (16.8) | 73.8 (37.4) | 60.6 (30.8) | |
| Int/ext oblique | 54.1 (21.1) | 79.7 (41.6) | 51.7 (28.4) | |
| Intercostal/diaphragm | 62.3 (18.1) | 184.0 (411.3) | 169.4 (342.0) | |
| Deltoid | 24.3 (22.5) | 78.6 (120.6) | 83.7 (100.6) | |
| Pectoralis major | 55.6 (28.9) | 136.6 (309.7) | 183.5 (392.2) | |
| Trapezius | 60.7 (34.2) | 96.4 (92) | 81.2 (73.4) | |
| Latissimus dorsi | 67.2 (33.1) | 122.9 (236.2) | 132.7 (245.8) | |
| EMG burst duration (ms) | ||||
| Rectus abdominis | 311 (69) | 213 (63) | 171 (63) | |
| Int/ext oblique | 313 (52) | 231 (66) | 173 (50) | |
| Intercostal/diaphragm | 318 (58) | 215 (52) | 197 (57) | |
| Deltoid | 218 (84) | 182 (59) | 177 (75) | |
| Pectoralis major | 260 (107) | 213 (81) | 187 (54) | |
| Trapezius | 218 (82) | 166 (83) | 151 (79) | |
| Latissimus dorsi | 283 (75) | 207 (56) | 184 (67) | |
| Mean expiratory muscles | 314 (60) | 220 (60) | 180 (57) | 0.001 |
| Mean accessory muscles | 245 (87) | 192 (70) | 175 (69) | 0.02 |
| Mean difference (exp−acc)* | 68 (47) | 27 (44) | 6 (31) | 0.005 |
| EMG burst onset (ms) | ||||
| Rectus abdominis | −104 (25) | −92 (26) | −90 (29) | |
| Int/ext oblique | −115 (30) | −96 (29) | −94 (29) | |
| Intercostal/diaphragm | −110 (35) | −101 (28) | −95 (28) | |
| Deltoid | −65 (51) | −87 (44) | −97(44) | |
| Pectoralis major | −76 (34) | −109 (42) | −101 (34) | |
| Trapezius | −79 (34) | −73 (33) | −84 (41) | |
| Latissimus dorsi | −89 (35) | −84 (40) | −81 (33) | |
| Mean expiratory muscles | −110 (32) | −96 (28) | −93 (29) | 0.107 |
| Mean accessory muscles | −77 (39) | −88 (40) | −90 (38) | 0.762 |
| Mean difference (exp−acc)* | 44 (34) | 8 (24) | 2 (27) | 0.0001 |
*Comparisons in individual subjects corrected for the quintile of flow rate for voluntary cough. Eight of the 10 subjects had a pair of reflex coughs allowing a second reflex cough to be averaged.