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Table 1 Characteristics of the participants completing the study

From: Chronic obstructive pulmonary disease does not impair responses to resistance training

  COPD Healthy Sex-adjusted estimated difference
COPD – Healthy (95% CI) P-value
General
 Participants, completing (no. ♂/♀) / dropouts† (no.) 20 (12/8) / 2 58 (21/37) / 2
 Age (years) 69 ± 5 (range, 60–79) 67 ± 4 (range, 57–78) 2 (0, 5) 0.049*
 Height (cm) 171 (10) 170 (10) −3 (−6, 0) 0.056
 Body mass (kg) 73 (18) 76 (16) −7 (−14, 0) 0.061
 Body mass index (kg. m2) 25 (5) 26 (5) −2 (−4, 1) 0.237
 Pack-years (no.) 30 (16) 6 (10) 23 (17, 29)  < 0.001*
 GOLD grade (no. of grade II/III) 15/5
 COPD Assessment Test™ score (0–40) 16.6 (6.8)
 Self-reported conception of health (0–10) 4.9 (1.2) 6.7 (1.6) − 1.7 (− 2.5, − 0.7) 0.001*
Physical activity level
 Household work (kcals.week−1) 1754 (2062) 1866 (2201) − 164 (− 1322, 995) 0.779
 Recreational activities (kcals.week−1) 2512 (2619) 2654 (1841) 188 (− 862, 1237) 0.723
 Total activity (kcals.week−1) 4266 (4036) 4520 (2837) 24 (− 1657, 1704) 0.978
Pulmonary function
 FVC (L) 3.2 (0.9) 3.6 (0.9) − 0.7 (− 1.0, − 0.4)  < 0.001*
 FVC (% predicted) 97 (19) 112 (16) − 13 (− 22, − 4) 0.003*
 FEV1 (L. sec−1) 1.5 (0.4) 2.7 (0.7) − 1.4 (− 1.6, − 1.2)  < 0.001*
 FEV1 (% predicted) 57 (11) 104 (16) − 47 (− 55, − 39)  < 0.001*
 FEV1/FVC (%) 47 (8) 75 (6) − 28 (− 31, − 24)  < 0.001*
 PEF (L. sec−1) 5.0 (1.6) 7.7 (2.1) − 3.4 (− 4.1, − 2.7)  < 0.001*
Pulmonary medication
 B2-agonists (no.) 17/20
 Muscarinic agonists (no.) 15/20
 Medication containing both b2-agonist and glucocorticoid (no.) 10/20
Body composition
 Total lean mass (kg) ♂, 53 (4); ♀, 36 (6) ♂, 60 (5); ♀, 41 (4) − 6 (− 9, − 4)  < 0.001*
 Whole-body bone mineral density (g. cm2) ♂, 1.2 (0.1); ♀, 1.0 (0.2) ♂, 1.3 (0.1); ♀, 1.1 (0.1) − 0.1 (− 0.2, − 0.0) 0.007*
 Total fat mass (kg) ♂, 26 (10); ♀, 27 (15) ♂, 26 (9); ♀, 25 (10) 1 (− 5, 7) 0.703
 Visceral fat (kg) ♂, 1.9 (1.3); ♀, 1.0 (0.7) ♂, 1.7 (1.0); ♀, 0.8 (0.7) 0.2 (− 0.3, 0.7) 0.412
Lower−-body muscle strength
 1RM leg press (kg) ♂, 121 (35); ♀, 82 (21) ♂, 152 (27); ♀, 124 (25) − 36 (− 47, − 26)  < 0.001*
 1RM knee extension (kg) ♂, 21 (4); ♀, 11 (4) ♂, 31 (5); ♀, 16 (3) − 7 (− 9, − 5)  < 0.001*
 Peak torque knee extension 60° . sec−1 (Nm) ♂, 127 (34); ♀, 80 (25) ♂, 160 32); ♀, 101 (16) − 27 (− 36, − 17)  < 0.001*
 Peak torque knee extension 180° . sec−1 (Nm) ♂, 83 (25); ♀, 47 (17) ♂, 102 (23); ♀, 62 (11) − 19 (− 28, − 9)  < 0.001*
 Peak torque knee extension 240° . sec−1 (Nm) ♂, 68 (20); ♀, 38 (14) ♂, 84 (20); ♀, 50 (9) − 15 (− 20, − 9)  < 0.001*
 Lower-body muscle strength factor (AU) ♂, 0.5 (0.1); ♀, 0.3 (0.1) ♂, 0.6 (0.1); ♀, 0.4 (0.1) − 0.1 (− 0.2, − 0.1)  < 0.001*
Lower-body muscle mass measures
 Leg lean mass (kg) ♂, 18 (2); ♀, 12 (3) ♂, 20 (2); ♀, 14 (2) − 3 (− 4, − 2)  < 0.001*
 M. vastus lateralis thickness (mm) ♂, 20 (3); ♀, 18 (5) ♂, 22 (3); ♀, 20 (3) − 2 (− 3, − 1) 0.002*
 M. rectus femoris thickness (mm) ♂, 13 (4); ♀, 10 (3) ♂, 16 (4); ♀, 15 (4) − 4 (− 5, − 2)  < 0.001*
 Lower-body muscle mass factor (AU) ♂, 0.6 (0.1); ♀, 0.5 (0.1) ♂, 0.7 (0.1); ♀, 0.6 (0.1) − 0.1 (− 0.2, − 0.1)  < 0.001*
Endurance measures
 Maximal power output one-legged cycling (W) ♂, 73 (13); ♀, 48 (17) ♂, 148 (28); ♀, 108 (21) − 67 (− 77, − 58)  < 0.001*
 Maximal power output two-legged cycling (W) ♂, 118 (38); ♀, 75 (32) ♂, 252 (48); ♀, 167 (32) − 113 (− 134, − 92)  < 0.001*
 Maximal oxygen consumption (mL O2. kg−1. min−1) ♂, 20 (5); ♀, 16 (5) ♂, 35 (7); ♀, 28 (6) − 14 (− 18, − 10)  < 0.001*
 6 min step test (maximal number of steps) ♂, 123 (35); ♀, 115 (44) ♂, 208 (41); ♀, 196 (38) − 83 (− 105, − 61)  < 0.001*
 1 min sit-to-stand test (maximal number) ♂, 21 (5); ♀, 21 (6) ♂, 30 (5); ♀, 29 (5) − 9 (− 12, − 6)  < 0.001*
 nrepetitions at 50% of 1RM knee extensionpre study ♂, 19 (5); ♀, 17 (5) ♂, 23 (6); ♀, 20 (7) − 4 (− 6, − 1) 0.005*
 One-legged endurance performance factor (AU) ♂, 0.2 (0.0); ♀, 0.2 (0.0) ♂, 0.4 (0.1); ♀, 0.3 (0.1) − 0.2 (− 0.2, − 0.1)  < 0.001*
 Whole-body endurance performance factor (AU) ♂, 0.4 (0.1); ♀, 0.3 (0.1) ♂, 0.7 (0.1); ♀, 0.6 (0.1) − 0.3 (− 0.3, − 0.2)  < 0.001*
  1. COPD, participants diagnosed with chronic obstructive pulmonary disease; Healthy, healthy control participants; ♂, males; ♀, females; †, dropouts during the training period; *study clusters are significantly different from each other (p < 0.05); GOLD, Global Initiative for Chronic Obstructive Lung Disease; pack-years, (number of cigarettes smoked per day/20) × number of years smoked; FVC, forced vital capacity; FEV1, forced expiratory volume in one second; PEF, peak expiratory flow; 1RM, one repetition maximum; Nm, newton-meter; AU, arbitrary units. Data mainly presented as mean (SD), and sex-adjusted estimated mean differences between study clusters (95% CI). For core outcome domains, i.e. lower-body muscle strength, lower-body muscle mass, one-legged endurance performance and whole-body endurance performance, factors were calculated. Briefly, each factor was calculated using multiple singular outcome measures, where each of these variables were normalized to the participant with the highest value recorded during the study, resulting in individual scores ≤ 1. Thereafter, outcome domain factors were calculated as the mean of the normalized values for each variable for each subject (see Additional file 1: Table S1 for complete overview over calculations and composition of each factor)