Introduction
Methods and materials
Participants
Measurement of anatomical cross-sectional area
Measurement of maximal isometric voluntary knee extension strength
Voluntary activation
Torque–frequency relationship and contractile speed
Fatigue test
Statistical analysis
Results
Subject characteristics
Male non-smokers | Male smokers | Female non-smokers | Female smokers | |
---|---|---|---|---|
n
| 22 | 19 | 23 | 21 |
Age (years) | 38.1 ± 17.8 (21–73) | 37.0 ± 18.4 (18–72) | 42.4 ± 20.4 (19–72) | 37.5 ± 17.4 (18–66) |
Body mass (kg) | 77 ± 9 (63–95) | 77 ± 12 (62–99) | 66 ± 3 (53–83)** | 74 ± 12 (56–96)** |
BMI (kg m−1) | 24 ± 2 (22–29) | 24 ± 3 (18–30) | 24 ± 3 (19–29) | 27 ± 4 (22–34) |
FVC (L) | 5.4 ± 1.0 (3.6–7.3) | 5.1 ± 1.3 (3.6–7.2) | 3.6 ± 0.7 (2.5–4.8)** | 3.7 ± 0.8 2.4–5.3)** |
FEV1 (L) | 4.3 ± 1.0 (2.8–6.1) | 4.0 ± 0.9 (2.6–5.6) | 3.0 ± 0.6 (2.0–3.9)** | 2.9 ± 0.8 (1.5–4.2)** |
%FEV1pred
| 99.3 ± 13.2 (78.7–125.5) | 91.0 ± 11.5 (81.0–111.8) | 101.2 ± 14.7 (76.4–127.8) | 92.0 ± 19.5 (47.6–119.9) |
FEV1/FVC (%) | 78.7 ± 6.6 (60.2–91.6) | 78.0 ± 9.4 (66.4–93.4) | 81.7 ± 4.8 (71.9–88.6) | 77.9 ± 10.5 (51.7–93.0) |
Physical activity level | 8.2 ± 1.4 (6.0–10.8) | 8.3 ± 1.4 (5.6–12.0) | 8.1 ± 1.2 (5.8–9.5) | 8.1 ± 1.4 (5.8–10.5) |
Muscle strength, size and voluntary activation level
Male non-smokers | Male smokers | Female non-smokers | Female smokers | |
---|---|---|---|---|
VA (%) | 85.9 (3.0) | 92.0 (2.3)†
| 88.1 (2.2) | 90.0 (3.3)†
|
MVC (Nm) | 286 (21) | 280 (18) | 190 (12)** | 204 (15)** |
MTC (Nm) | 330 (18) | 300 (19) | 213 (12)** | 219 (15)** |
ACSA (cm2) | 72 (2) | 65 (3) | 53 (2) | 52 (2) |
FF10/FF100
| 31.3 (1.4) | 31.4 (3.0) | 33.3 (1.5)* | 38.0 (2.0)* |
MRR50 (s−1) | −15.1 (0.3) | −16.0 (0.7) | −12.7 (0.4)** | −12.9 (0.8)** |