Introduction
Methods
Participants and procedures
Assessment methods
Physical capacity
Occupational physical demands
Relative physical strain
Demographic, health-related, and work-related information
Data analysis
Results
Construction | Healthcare | |||||||
---|---|---|---|---|---|---|---|---|
Total n = 62 | ≤ 44 years n = 39 | ≥ 45 years n = 23 |
p
| Total n = 64 | ≤ 44 years n = 33 | ≥ 45 years n = 31 |
p
| |
n (%) | n (%) | n (%) | n (%) | n (%) | n (%) | |||
Gender | ||||||||
Male | 61 (98) | 38 (97) | 23 (100) | 0.629 | 14 (22) | 8 (24) | 6 (19) | 0.337 |
Female | 1 (2) | 1 (3) | 0 (0) | 50 (78) | 25 (76) | 25 (81) | ||
Level of physical demands (DOT) | ||||||||
Sedentary/light work | 16 (26) | 8 (21) | 8 (35) | 0.242 | 8 (13) | 5 (15) | 3 (10) | 0.709 |
Medium intensity work | – | – | – | 56 (87) | 28 (85) | 28 (90) | ||
Heavy work | 46 (74) | 31 (79) | 15 (65) | – | – | – | ||
General health | ||||||||
Very good to excellent | 28 (45) | 21 (54) | 7 (30) | 0.192 | 30 (47) | 14 (42) | 16 (52) | 0.568 |
Good | 26 (42) | 14 (36) | 12 (52) | 25 (39) | 13 (40) | 12 (38) | ||
Poor to fair | 8 (13) | 4 (10) | 4 (18) | 9 (14) | 6 (18) | 3 (10) | ||
BMI | ||||||||
Normal (< 25 kg/m2) | 25 (40) | 17 (44) | 8 (35) | 0.596 | 34 (53) | 20 (61) | 14 (45) | 0.316 |
Overweight (> 25 kg/m2) | 37 (60) | 22 (56) | 15 (65) | 30 (47) | 13 (39) | 17 (55) | ||
Shoulder pain | ||||||||
No pain—a little pain | 50 (85) | 32 (87) | 18 (82) | 0.715 | 40 (67) | 16 (53) | 24 (80) | 0.054 |
Moderate—severe pain | 9 (15) | 5 (13) | 4 (18) | 20 (33) | 14 (47) | 6 (20) | ||
Lower back pain | ||||||||
No pain—a little pain | 45 (74) | 30 (79) | 15 (65) | 0.368 | 40 (65) | 18 (56) | 22 (73) | 0.192 |
Moderate—severe pain | 16 (26) | 8 (21) | 8 (35) | 22 (35) | 14 (44) | 8 (27) | ||
Subjective work demands | ||||||||
Not at all—light | 15 (24) | 8 (21) | 7 (30) | 0.177 | 21 (33) |
14 (44)
|
7 (23)
|
0.013
|
Moderate—somewhat heavy | 31 (50) | 23 (58) | 8 (35) | 27 (43) |
8 (25)
|
19 (61)
| ||
Heavy—very, very heavy+ | 15 (26) | 8 (21) | 8 (35) | 15 (24) |
10 (31)
|
5 (16)
| ||
Preventative exercises | ||||||||
No | 21 (34) | 12 (31) | 9 (39) | 0.583 | 13 (20) | 7 (21) | 6 (19) | 1.000 |
Yes | 41 (66) | 27 (69) | 14 (61) | 51 (80) | 26 (79) | 25 (81) | ||
Leisure physical activity | ||||||||
Sedentary—some activity | 40 (71) | 22 (67) | 18 (78) | 0.385 | 38 (73) | 16 (64) | 22 (82) | 0.215 |
Regular—hard activity | 16 (29) | 11 (33) | 5 (22) | 14 (27) | 9 (36) | 5 (18) |
Construction | Healthcare | |||||||
---|---|---|---|---|---|---|---|---|
Total n = 62 | ≤ 44 years n = 39 | ≥ 45 years n = 23 |
p
| Total n = 64 | ≤ 44 years n = 33 | ≥ 45 years n = 31 |
p
| |
m (SD) | m (SD) | m (SD) | m (SD) | m (SD) | m (SD) | |||
Age (years) | 39.9 (13.4) |
31.0 (6.5)
|
55.1 (6.7)
| < 0.001 | 44.1 (9.9) |
36.3 (6.0)
|
52.5 (5.1)
| < 0.001 |
Weekly working hours | 37.8 (4.0) | 37.6 (5.0) | 38.2 (1.1) | 0.542 | 35.7 (4.2) | 35.7 (3.3) | 35.6 (5.0) | 0.919 |
Work ability (0–10) | 8.9 (1.5) | 8.5 (1.7) | 9.4 (0.8) | 0.054 | 8.8 (1.3) | 8.7 (1.2) | 8.9 (1.5) | 0.398 |
QPS job demands (1–5) | 3.0 (0.6) | 3.1 (0.5) | 2.9 (0.6) | 0.276 | 3.0 (0.7) | 3.0 (0.8) | 3.0 (0.7) | 0.814 |
QPS job control (1–5) | 3.2 (0.7) | 3.2 (0.7) | 3.3 (0.8) | 0.483 | 2.9 (0.8) | 3.0 (0.8) | 2.8 (0.7) | 0.454 |
Age inequality (1–5) | 2.1 (0.9) |
2.4 (0.8)
|
1.6 (0.7)
| < 0.001 | 2.1 (1.2) | 2.4 (1.4) | 1.8 (0.9) | 0.088 |
Physical capacity
Shoulder strength (kg) | Back strength (kg) | VO2max (L/min/kg) | |||||||
---|---|---|---|---|---|---|---|---|---|
n
| m (SD) |
p
|
n
| m (SD) |
p
|
n
| m (SD) |
p
| |
Construction | |||||||||
Male (n = 61) | |||||||||
≤ 44 years | 38 | 28.2 (6.9) | 38 | 48.4 (14.8) | 34 |
41.3 (12.2)
| |||
≥ 45 years | 23 | 28.2 (9.7) | 0.990 | 21 | 49.0 (17.5) | 0.879 | 22 |
33.1 (5.2)
|
0.001
|
Healthcare | |||||||||
Male (n = 14) | |||||||||
≤ 44 years | 8 | 24.2 (5.2) | 8 | 47.1 (23.0) | 7 | 38.7 (13.1) | |||
≥ 45 years | 6 | 24.4 (6.9) | 0.953 | 6 | 38.6 (13.8) | 0.440 | 6 | 26.7 (7.2) | 0.071 |
Female (n = 50) | |||||||||
≤ 44 years | 25 | 15.4 (3.6) | 24 | 30.2 (10.2) | 24 | 33.4 (9.0) | |||
≥ 45 years | 25 | 13.6 (4.4) | 0.108 | 25 | 26.9 (10.7) | 0.275 | 23 | 29.0 (5.1) | 0.091 |
Occupational physical demands
Age (year) | Construction | Healthcare | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
n (%) | Median | m (SD) | Min–max |
p
| n (%) | Median | m (SD) | Min–max |
p
| ||
Upper-arm elevation | |||||||||||
> 30° duration (% working day) | ≤ 44 | 37 (100) | 41.3 | 41.9 (11.6) | 22.4–82.1 | 0.907 | 30 (100) | 30.0 | 29.8 (12.5) | 10.0–56.4 | 0.291 |
≥ 45 | 22 (100) | 41.8 | 41.5 (16.3) | 5.3–79.5 | 31 (100) | 32.3 | 32.8 (8.7) | 11.7–48.2 | |||
> 30° frequency (#/h) | ≤ 44 | 37 (100) | 37.0 | 38.1 (14.0) | 15.6–62.5 | 0.900 | 30 (100) |
27.6
|
28.2 (9.1)
|
10.7–48.3
|
0.017
|
≥ 45 | 22 (100) | 37.6 | 36.4 (17.7) | 1.7–62.0 | 31 (100) |
35.1
|
35.9 (13.6)
|
15.9–81.1
| |||
> 60° duration (% working day) | ≤ 44 | 37 (100) | 7.6 | 8.6 (4.9) | 1.1–17.6 | 0.888 | 30 (100) |
2.9
|
3.2 (1.7)
|
1.3–8.5
|
0.039
|
≥ 45 | 22 (100) | 8.0 | 8.7 (6.1) | 0.5–21.0 | 31 (100) |
3.9
|
4.3 (2.3)
|
0.8–11.0
| |||
> 60° frequency (#/h) | ≤ 44 | 37 (100) | 8.7 | 9.8 (6.2) | 1.5–23.6 | 0.638 | 30 (100) |
3.6
|
4.1 (1.9)
|
1.5–8.7
|
0.045
|
≥ 45 | 22 (100) | 6.5 | 9.0 (6.7) | 0.1–22.3 | 31 (100) |
5.3
|
5.5 (2.7)
|
1.3–10.8
| |||
> 60° for > 10% working day (% working day) | ≤ 44 | 15 (41) | 13.1 | 13.8 (1.9) | 10.8–17.6 | 0.466 | 0 (0) | ||||
≥ 45 | 8 (36) | 14.6 | 15.3 (83.6) | 11.0–21.0 | 1 (3) | ||||||
Trunk flexion | |||||||||||
> 30° duration (% working day) | ≤ 44 | 33 (100) | 18.6 | 20.6 (10.2) | 2.7–50.8 | 0.314 | 30 (100) |
16.4
|
17.5 (8.1)
|
4.3–35.7
|
0.002
|
≥ 45 | 22 (100) | 16.1 | 17.9 (9.0) | 8.0–42.5 | 30 (100) |
25.0
|
24.4 (8.4)
|
3.2–44.8
| |||
> 30° frequency (#/h) | ≤ 44 | 33 (100) | 21.0 | 24.2 (13.6) | 3.3–65.2 | 0.236 | 30 (100) |
17.6
|
20.5 (8.9)
|
4.8–41.2
|
0.001
|
≥ 45 | 22 (100) | 17.2 | 20.2 (11.3) | 7.0–46.7 | 30 (100) |
27.7
|
30.9 (14.2)
|
5.0–71.3
| |||
> 60° duration (% working day) | ≤ 44 | 33 (100) | 9.0 | 8.7 (6.1) | 0.3–29.1 | 0.086 | 30 (100) |
3.5
|
4.7 (3.3)
|
0.7–12.8
|
0.008
|
≥ 45 | 22 (100) | 3.9 | 6.5 (6.5) | 0.7–26.7 | 30 (100) |
7.4
|
7.5 (4.3)
|
0.1–19.2
| |||
> 60 frequency (#/h) | ≤ 44 | 33 (100) | 9.2 | 10.4 (8.1) | 0.5–41.5 | 0.118 | 30 (100) |
4.2
|
5.3 (3.6)
|
1.1–14.5
|
0.002
|
≥ 45 | 22 (100) | 5.5 | 7.4 (6.0) | 0.7–20.4 | 30 (100) |
9.3
|
9.9 (6.2)
|
0.3–24.7
| |||
> 60° for > 10% working day (% working day) | ≤ 44 | 15 (45) | 10.9 | 13.6 (5.2) | 10.1–29.1 | 0.349 | 2 (7) | 11.9 | 11.9 (1.3) | 11.0–12.8 | |
≥ 45 | 5 (23) | 16.1 | 16.3 (5.9) | 10.2–26.7 | 7 (23) | 12.2 | 13.5 (2.8) | 11.3–19.2 | |||
Occupational physical activity | |||||||||||
Stand/move/walk (% working day) | ≤ 44 | 37 (100) | 76.5 | 71.1 (18.9) | 18.4–92.5 | 0.962 | 30 (100) | 62.1 | 60.3 (22.9) | 13.1–93.4 | 0.657 |
≥ 45 | 22 (100) | 80.4 | 63.6 (28.9) | 9.4–93.0 | 30 (100) | 67.1 | 63.9 (18.5) | 23.6–91.5 | |||
Stand/move/walk > 75% working day (% working day) | ≤ 44 | 22 (59) | 80.2 | 82.0 (5.6) | 75.2–92.5 | 0.200 | 11 (37) | 84.6 | 84.1 (4.9) | 75.5–93.4 | 0.657 |
≥ 45 | 13 (59) | 83.8 | 84.1 (4.6) | 76.1–93.0 | 10 (33) | 80.7 | 81.7 (5.2) | 75.9–91.5 |
Relative physical strain
Age (year) | Construction | Healthcare | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
n (%) | Median | m (SD) | Min–max |
p
| n (%) | Median | m (SD) | Min–max |
p
| ||
Upper trapezius muscle activity | |||||||||||
> 15% sEMGmax (% working day) | ≤ 44 | 21 (100) |
3.9
|
5.4 (4.2)
|
0.7–13.2
|
0.004
| 27 (100) |
3.4
|
6.0 (5.4)
|
0.8–17.2
|
0.018
|
≥ 45 | 18 (100) |
8.3
|
12.7 (10.1)
|
1.4–36.1
| 29 (100) |
11.3
|
11.9 (10.0)
|
0.9–32.3
| |||
Muscular rest (% working day) | ≤ 44 | 21 (100) |
17.8
|
21.7 (12.4)
|
2.3–55.5
|
0.003
| 27 (100) | 9.5 | 12.7 (11.6) | 1.1–39.1 | 0.594 |
≥ 45 | 18 (100) |
9.6
|
12.3 (9.3)
|
2.9–40.9
| 29 (100) | 11.5 | 12.2 (7.8) | 0.4–29.4 | |||
Median load (%sEMGmax) | ≤ 44 | 21 (100) |
2.0
|
2.3 (1.3)
|
0.4–4.9
|
0.005
| 27 (100) | 2.8 | 3.6 (2.3) | 0.8–9.3 | 0.166 |
≥ 45 | 18 (100) |
3.9
|
4.5 (2.7)
|
1.2–10.0
| 29 (100) | 3.5 | 4.4 (2.6) | 1.0–9.6 | |||
Peak load (%sEMGmax) | ≤ 44 | 21 (100) |
10.1
|
10.6 (4.1)
|
4.9–18.0
|
0.004
| 27 (100) |
10.0
|
11.0 (4.3)
|
5.8–17.8
|
0.019
|
≥ 45 | 18 (100) |
13.8
|
16.8 (8.2)
|
7.8–40.0
| 29 (100) |
15.9
|
15.4 (7.1)
|
5.7–33.1
| |||
Freq. > 63% sEMGmax (#/h) | ≤ 44 | 19 (90) |
3.8
|
6.4 (6.5)
|
0.3–20.8
|
0.033
| 25 (93) |
1.5
|
3.6 (4.5)
|
0.2–14.8
|
0.014
|
≥ 45 | 17 (94) |
11.1
|
36.2 (72.1)
|
0.1–302.4
| 29 (100) |
4.9
|
13.7 (26.7)
|
0.3–121.7
| |||
Erector spinae muscle activity | |||||||||||
> 15% sEMGmax (% working day) | ≤ 44 | 14 (100) | 7.5 | 9.5 (7.5) | 1.6–24.5 | 0.212 | 15 (100) |
6.5
|
10.4 (11.0)
|
0.4–37.3
|
0.019
|
≥ 45 | 8 (100) | 14.3 | 20.3 (17.8) | 1.3–53.4 | 13 (100) |
19.6
|
22.9 (14.1)
|
2.4–44.8
| |||
Muscular rest (% working day) | ≤ 44 | 14 (100) | 9.0 | 14.2 (13.0) | 2.7–47.8 | 0.110 | 15 (100) |
12.4
|
16.0 (13.7)
|
1.6–47.4
|
0.025
|
≥ 45 | 8 (100) | 2.7 | 8.3 (11.0) | 0.1–30.5 | 13 (100) |
4.1
|
5.9 (5.0)
|
1.2–16.6
| |||
Median load (%sEMGmax) | ≤ 44 | 14 (100) | 3.5 | 3.5 (1.8) | 0.6–5.7 | 0.238 | 15 (100) |
3.1
|
3.6 (2.9)
|
0.6–10.4
|
0.007
|
≥ 45 | 8 (100) | 6.4 | 6.6 (5.2) | 1.1–16.3 | 13 (100) |
5.9
|
7.2 (3.4)
|
2.7–12.5
| |||
Peak load (%sEMGmax) | ≤ 44 | 14 (100) | 13.2 | 14.2 (4.9) | 8.1–23.6 | 0.212 | 15 (100) |
12.5
|
14.1 (8.4)
|
4.2–33.1
|
0.013
|
≥ 45 | 8 (100) | 17.6 | 20.3 (11.6) | 7.0–44.7 | 13 (100) |
20.5
|
22.9 (9.7)
|
8.0–42.1
| |||
Freq. > 63% sEMGmax (#/h) | ≤ 44 | 11 (79) | 1.9 | 8.2 (13.5) | 0.1–45.8 | 0.525 | 11 (73) | 1.7 | 11.7 (25.1) | 0.2–84.0 | 0.051 |
≥ 45 | 6 (75) | 5.2 | 54.6 (123.3) | 1.2–306.2 | 12 (92) | 6.2 | 66.7 (74.9) | 0.9–254.0 | |||
%HRR | |||||||||||
Average %HRR | ≤ 44 | 29 (100) | 34.0 | 33.2 (10.4) | 15.2–54.5 | 0.097 | 30 (100) | 23.9 | 25.5 (5.7) | 17.9–36.8 | 0.079 |
≥ 45 | 17 (100) | 28.5 | 29.2 (5.6) | 21.8–44.3 | 26 (100) | 30.1 | 29.1 (8.6) | 13.7–45.7 | |||
> 33% HRR (% working day) | ≤ 44 | 29 (100) | 55.2 | 49.5 (34.1) | 1.8–93.5 | 0.054 | 30 (100) | 12.0 | 21.4 (21.2) | 0.4–64.7 | 0.071 |
≥ 45 | 17 (100) | 26.2 | 31.1 (18.9) | 6.8–75.0 | 26 (100) | 35.5 | 35.4 (26.8) | 0.04–84.6 |
Sensitivity analyses
Association between capacity and demands in relation to age
Construction (n = 62) | Arm elevation > 60° (% working day)a | Trunk flexion > 60° (% working day)b | Occupational physical activity (% working day)c |
---|---|---|---|
Exp(b) (95% CI) | b (95% CI) | Sqrt(b) (95% CI) | |
n = 59 | n = 53 | n = 55 | |
Crude model | |||
Capacity indicator | 1.00 (0.96–1.04) | 0.04 (− 0.10 to 0.18) | − 3.66 (− 9.19 to 7.60) |
Age | |||
≤ 44 years | 1.00 | 0.00 | 0.00 |
≥ 45 years | 0.14 (0.03–0.68) | − 6.72 (− 17.60 to 4.15) | − 89.59 (− 124.96 to 20.95) |
Capacity indicator × age |
1.07 (1.01–1.12)
| 0.11 (− 1.00 to 0.33) |
15.21 (3.38–21.24)
|
Adjusted model | |||
Capacity indicator | 1.01 (0.98–1.04) | 5.83 (− 1.97 to 8.47) | |
Age | |||
≤ 44 years | 1.00 | 0.00 | |
≥ 45 years | 0.45 (0.13–1.60) | − 14.54 (− 66.13 to 62.85) | |
Capacity indicator × age | 1.03 (0.98–1.07) | 4.52 (− 9.97 to 11.84) | |
Level of work demands | |||
Sedentary/light work | 1.00 | 0.00 | |
Heavy work |
3.43 (2.30–5.11)
|
69.69 (63.48–75.39)
|
Healthcare (n = 64) | Arm elevation > 60° (% working day)a | Trunk flexion > 60° (% working day)b | Occupational physical activity (% working day)c |
---|---|---|---|
Exp(b) (95% CI) | b (95% CI) | Sqrt(b) (95% CI) | |
n = 61 | n = 59 | n = 56 | |
Crude model | |||
Capacity indicator | 0.99 (0.96–1.03) | − 0.02 (− 0.11 to 0.07) | − 5.92 (− 11.23 to 7.48) |
Age | |||
≤ 44 years | 1.00 | 0.00 | 0.00 |
≥ 45 years | 0.81 (0.34–1.92) | 3.54 (− 1.52 to 8.59) | 40.34 (− 68.06 to 88.81) |
Capacity indicator × age | 1.03 (0.98–1.08) | − 0.03 (− 0.18 to 0.12) | − 6.38 (− 15.54 to 12.65) |