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 coughReflex cough (R1)Reflex cough (R2)p value
*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.
Normalised EMG activity
Rectus abdominis68.2 (16.8)73.8 (37.4)60.6 (30.8)
Int/ext oblique54.1 (21.1)79.7 (41.6)51.7 (28.4)
Intercostal/diaphragm62.3 (18.1)184.0 (411.3)169.4 (342.0)
Deltoid24.3 (22.5)78.6 (120.6)83.7 (100.6)
Pectoralis major55.6 (28.9)136.6 (309.7)183.5 (392.2)
Trapezius60.7 (34.2)96.4 (92)81.2 (73.4)
Latissimus dorsi67.2 (33.1)122.9 (236.2)132.7 (245.8)
EMG burst duration (ms)
Rectus abdominis311 (69)213 (63)171 (63)
Int/ext oblique313 (52)231 (66)173 (50)
Intercostal/diaphragm318 (58)215 (52)197 (57)
Deltoid218 (84)182 (59)177 (75)
Pectoralis major260 (107)213 (81)187 (54)
Trapezius218 (82)166 (83)151 (79)
Latissimus dorsi283 (75)207 (56)184 (67)
Mean expiratory muscles314 (60)220 (60)180 (57)0.001
Mean accessory muscles245 (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