Baseline characteristics
The baseline characteristics of the study population are presented in Table 2. No significant difference between the four groups was observed in height, weight, body mass index, and age. There was a significant difference in seniority between the SWU group and the CONTROL group (p < 0.05). Effect size for the difference in seniority was 0.72, which was categorized as medium.
Table 2
Baseline characteristics of the study population
Participants | CONTROL | HWU | SWU | DWU |
demographics |
Gender: female (%) | 26,67 | 40,00 | 14,81 | 20,00 |
Height (cm) | 172.60 (10.60) | 172.28 (8.06) | 171.48 (8.69) | 171.24 (7.99) |
Weight (kg) | 76.73 (8.85) | 75.28 (14.09) | 77.00 (14.10) | 71.68 (10.64) |
BMI (kg/m2) | 25.82 (2.86) | 25.34 (4.19) | 26.20 (4.63) | 24.54 (4.03) |
Age (years) | 37.27 (11.05) | 39.96 (11.21) | 39.93 (11.83) | 35.00 (11.87) |
Seniority (years) | 8.87 (8.01) | 14.40 (11.19) | 17.56 (11.57) * | 10.88 (10.03) |
Values are presented as mean (standard deviation)
* p < 0.05 the difference with the CONTROL group
The perceived pain intensity at baseline (during the 3 last months and at T0) for the fifteen pain locations are presented in supplementary material (see Additional file 2). Only the lower back area was concerned by pain > 2 on the 0–10 scale during the 3 last months for the four groups.
The perceived pain intensity for the lower back area is presented in Table 3. There was no significant difference in interaction between the four groups and times of measurement. There was a group effect as pain intensity was significantly higher in the CONTROL group (p < 0.05). There was also a time effect as firstly, the mean pain during the last 3 months was higher than at T0, T1 and T2 (p < 0.05) but there was no significant difference between the mean pain during the last 3 months and T3 and T4. Secondly, pain at T4 was higher than T0 (p < 0.05), and pain at T3 and T4 were higher than T1 (p < 0.05).
Table 3
Perceived pain intensity at the low back
Pain at the Low Back | CONTROL | HWU | SWU | DWU |
3 last months | 3.60 (3.27) | 2.56 (3.12) | 2.04 (2.58) | 2.32 (2.98) |
T0 | 1.87 (2.85) | 0.72 (1.99) | 0.96 (1.72) | 0.88 (1.83) |
T1 | 1.87 (3.14) | 0.56 (1.56) | 0.59 (1.37) | 0.64 (1.60) |
T2 | 2.80 (3.32) | 0.84 (1.80) | 1.07 (1.64) | 0.88 (1.59) |
T3 | 3.07 (2.74) | 1.16 (2.06) | 1.56 (2.15) | 1.72 (2.41) |
T4 | 3.31 (3.47) | 1.93 (2.40) | 1.95 (1.84) | 1.68 (2.63) |
Values are presented as mean (standard deviation)
All measurements are on a 0–10 scale
The work performance results are presented in Table 4. No significant difference was observed in interaction between groups and times of measurement. There was a significant difference between groups as performance in DWU was higher than CONTROL group (p < 0.05). No significant different was observed between groups in total work performance.
Table 4
Work performance at T2, T3, T4, and total work performance.
Work performance | CONTROL | HWU | SWU | DWU |
T2 | 150.40 (80.11) | 154.32 (70.68) | 156.67 (86.55) | 159.20 (50.71) |
T3 | 140.40 (72.22) | 148.60 (60.49) | 165.67 (95.21) | 177.18 (51.22) |
T4 | 145.20 (56.02) | 157.36 (66.54) | 151.67 (78.73) | 172.24 (62.30) |
Total | 436.00 (203.34) | 460.28 (191.27) | 474.00 (251.21) | 508.64 (151.40) |
Values are presented as mean (standard deviation)
All measurements are in number of pruned vines
* p < 0.05 the difference with the CONTROL group
Results obtained for the physical capacities are presented in Table 5. No significant difference between the four groups was observed for the handgrip test. There was a significant difference between groups as the mean FTF score was better in the DWU group than the others groups (p < 0.05). There were significant differences between groups for the back scratch tests. The mean score in Right Back Scratch was better in CONTROL and DWU than SWU (p < 0.05). The mean score in Left Back Scratch was significantly better in CONTROL, HWU and DWU than SWU (p < 0.05).
The VMRT results are presented in Table 5. No significant difference in interaction between groups and time of measurement were observed in the mean error VMRT, the mean time VMRT, and the total time VMRT. There was a significant difference between times of measurement. Time and mean time were significantly higher at T4 than T1 (p < 0.05). Mean error was significantly higher at T0 than T1 and T4 (p < 0.05).
Table 5
Handgrip, Fingertip-to-floor, Back scratch, and Visuo-Motor Reaction Time tests results
Outcomes | Time of measurement | CONTROL | HWU | SWU | DWU |
Handgrip Strength (kg) | T0 | 42.17 (11.33) | 39.50 (9.59) | 42.90 (11.14) | 43.64 (9.53) |
T1 | 42.40 (10.96) | 40.06 (10.27) | 43.80 (12.78) | 43.72 (9.22) |
T4 | 43.65 (12.92) | 42.14 (9.64) | 45.40 (11.92) | 45.00 (9.58) |
Fingertip-to-floor (cm) | T0 | 19.90 (10.21) | 24.20 (12.36) | 23.07 (10.64) | 14.40 (10.14) |
T1 | 19.13 (10.46) | 21.36 (12.54) | 20.26 (10.48) | 12.88 (9.13) |
T4 | 16.33 (7.41) | 20.14 (10.75) | 19.00 (10.08) | 11.24 (9.41) |
Right Back Scratch (cm) | T0 | 9.07 (15.93) | 9.48 (11.22) | 14.07 (13.14) | 6.00 (10.48) |
T1 | 6.53 (11.26) | 7.12 (11.88) | 12.41 (13.61) | 5.72 (11.35) |
T4 | 6.13 (10.08) | 8.00 (11.39) | 13.81 (14.23) | 5.16 (10.80) |
Left Back Scratch (cm) | T0 | 9.93 (12.98) | 14.84 (14.07) | 21.70 (11.99) | 11.44 (10.95) |
T1 | 8.73 (13.01) | 12.72 (12.60) | 19.15 (11.49) | 10.76 (11.54) |
T4 | 8.60 (13.74) | 13.64 (12.00) | 19.33 (12.26) | 11.08 (11.10) |
Mean Error VMRT (number) | T0 | 3.13 (2.61) | 4.50 (5.64) | 6.00 (7.75) | 4.92 (4.23) |
T1 | 2.27 (3.20) | 1.17 (1.61) | 2.52 (2.99) | 2.52 (2.82) |
T4 | 2.60 (3.02) | 2.60 (2.81) | 2.30 (3.38) | 3.08 (2.25) |
Mean Time VMRT (s) | T0 | 0.73 (0.19) | 0.69 (0.10) | 0.68 (0.09) | 0.66 (0.08) |
T1 | 0.67 (0.12) | 0.65 (0.07) | 0.66 (0.08) | 0.64 (0.08) |
T4 | 0.71 (0.13) | 0.70 (0.13) | 0.73 (0.14) | 0.68 (0.09) |
Total Time VMRT (s) | T0 | 50.02 (11.30) | 51.02 (8.22) | 49.66 (5.65) | 48.71 (4.86) |
T1 | 48.10 (7.55) | 48.01 (4.48) | 48.58 (4.94) | 47.13 (4.94) |
T4 | 50.37 (8.35) | 50.95 (7.76) | 52.87 (8.79) | 47.32 (11.14) |
Values are presented as mean (standard deviation)
* p < 0.05 the difference
The heart rate results are presented in Table 6. A T0, there were no significant difference between the four groups. For the three intervention groups, the heart rate at T1 was higher than T0 (p < 0.001). For the CONTROL group, the heart rate at T1 was similar to T0. The heart rate at T1 was significantly higher in the HWU group and DWU group than the heart rate at T1 in the CONTROL group (p < 0.001). Effect size for the difference was 1.3 for both the HWU group and the DWU group, which was categorized as large. For the DWU group, the heart rate at T1 was significantly higher than the heart rate at T1 in the SWU group (p < 0.001). Effect size for the difference was 0.9, which was categorized as large. For the CONTROL group, the heart rate was significantly higher at T2, T3, and T4 than T0 (p < 0.001) and T1. For the intervention groups, the heart rate at T2, T3, and T4 was significantly higher than the heart rate at T0. For the intervention groups, there was no significant difference in the heart rate at T2, T3, and T4.
The RHR results are presented in Table 6. At T1, the RHR in the DWU group was higher than the CONTROL, HWU, and SWU groups (p < 0.001). Effect size for the differences was 5.0 for the CONTROL group, 1.48 for the HWU group, and 1.89 for the SWU group which were all categorized as large. There was no significant difference in the RHR between the CONTROL, HWU, and SWU groups at T1. The RHR was significantly higher at T2 and T4 than at T1 for the CONTROL group (p < 0.05). In the DWU, the RHR was higher at T2 and T4 than at T1 in the CONTROL group (p < 0.05).
Table 6
Heart Rate and Relative Heart Rate
Time of measurement | CONTROL | HWU | SWU | DWU |
HR (bpm) | RHR (%) | HR (bpm) | RHR (%) | HR (bpm) | RHR (%) | HR (bpm) | RHR (%) |
T0 | 65,50 (6,27) | 0 (0) | 70,42 (9,66) | 0 (0) | 64,44 (8,05) | 0 (0) | 62,41 (5,90) | 0 (0) |
T1 | 78,22 (6,09) | 10.97 (4.29) | 93,15 (11,00) ***, ††† | 20.47 (8.12) | 88,33 (8,67) *** | 20.65 (6.25) | 101,31 (12,82) ***, †††, ΔΔΔ | 32.48 (11.33) ●●● |
T2 | 95,07 (7,12) ***, ††† | 25.64 (7.20) ● | 95,47 (11,67) ***, ††† | 19.07 (17.99) | 90,97 (8,39) ***, ††† | 23.12 (5.48) | 91,62 (9,45) ***, ††† | 24.40 (6.86) ● |
T3 | 93,84 (6,67) ***, †† | 24.52 (7.40) | 96,56 (13,11) ***, ††† | 19.71 (19.58) | 90,08 (8,88) ***, ††† | 22.44 (7.04) | 89,78 (8,89) ***, † | 23.11 (6.26) |
T4 | 99,32 (7,74) ***, ††† | 28.52 (7.17) ● | 95,59 (13,77) ***, ††† | 18.89 (22.37) | 88,89 (8,30) *** | 22.41 (6.70) | 92,84 (8,72) ***, †† | 25.14 (7.81) ● |
Values are presented as mean (standard deviation)
* p < 0.05, ** p < 0.01, *** p < 0.001 the difference with T0 in HR
† p < 0.05, †† p < 0.01, ††† p < 0.001 the difference with CONTROL group at T1 in HR
Δ p < 0.05, ΔΔ p < 0.01, ΔΔΔ p < 0.001 the difference with SWU group at T1 in HR
● p < 0.05, ●● p < 0.01, ●●●p < 0.001 the difference with CONTROL group at T1in RHR
The NASA TLX results are presented in Table 7. No significant difference between the four groups was observed in the physical demand, temporal demand, effort, and frustration items. There was a significant difference in mental demand between the SWU group and the DWU group (p < 0.05). Effect size for the difference was 0.79, which was categorized as medium. There was a significant difference in performance between the SWU group and the CONTROL group (p < 0.05). Effect size for the difference was 0.81, which was categorized as large. There was a significant difference between CONTROL and DWU groups in the NASA TLX global score (p < 0.05). Effect size for the difference was 0.80, which was categorized as large.
Results obtained for the readiness to work and work quality are presented in Table 7. Readiness to work was higher in the HWU group (p < 0.01) and the DWU group (p < 0.05) than the CONTROL group. Effect size for the difference was 0.9 for the HWU group, which was categorized as large and 0.79 for the DWU group which was categorized as medium. There was a significant difference in work quality between the SWU group and the CONTROL group (p < 0.05). Effect size for the difference was 0.83 which was categorized as large.
Table 8
NASA TLX, Readiness to work and work quality results
Work perceptions | CONTROL | HWU | SWU | DWU |
NASA TLX (0-100) | Mental Demand | 39.33 (26.04) | 33.60 (17.77) | 38.15 (24.66) | 21.60 (20.55) † |
Physical Demand | 46.00 (17.65) | 37.60 (23.32) | 41.85 (21.31) | 33.20 (18.19) |
Temporal Demand | 43.33 (29.44) | 33.6 (20.39) | 40.37 (26.38) | 27.6 (19.85) |
Performance | 37.33 (15.34) | 32.00 (23.09) | 21.11 (18.67) * | 26.00 (18.71) |
Effort | 47.33 (19.44) | 39.60 (20.10) | 41.85 (20.76) | 34.80 (12.29) |
Frustration | 17.33 (17.51) | 19.60 (24.75) | 24.81 (26.07) | 17.20 (23.72) |
Global Score | 38.44 (14.13) | 32.67 (14.90) | 34.69 (14.68) | 26.73 (13.38) * |
Perceptions (0–10) | Readiness to work | 6.40 (2.47) | 8.72 (1.49) ** | 7.93 (2.76) | 8.36 (1.22) * |
Work Quality | 7.20 (1.15) | 7.76 (1.01) | 8.37 (1.28) * | 7.84 (0.80) |
Values are presented as mean (standard deviation)
* p < 0.05, ** p < 0.01 the difference with the CONTROL group
† p < 0.05 the difference with the SWU group