Chart 1. Studies included for review, effects, assessment measurements and methodological quality according to the PEDro scale, Salvador, 2017.

Author, year	Population	Intervention	Follow-up	Outcome	Assessment	Results	PEDro score
Telles et al., 200917	291 professional computer users	Intervention (n=146): yoga program Control (n=145): usual recreational activities	2 months	Musculoskeletal discomfort and low back flexibility	Musculoskeletal disorders were assessed with the Nordic Musculoskeletal Questionnaire; flexibility testing	Group intervention exhibited significant reduction of musculoskeletal discomfort (p<0.01) and improved low back flexibility (p<0.001)	5/10
Kamioka et al., 201118	88 female caregivers in nursing homes	Intervention (n=44): stretching exercises based on the MacKenzie method and orientation on posture Control (n=44): orientation on exercise	12 weeks	Low back pain	Low back pain was assessed on Visual Analogue Scale (VAN)	Improvement in intervention group was not significant; no changes on VAS. However, the control group exhibited higher scores (p=0.068)	5/10
Del Pozo-Cruz et al., 201219	100 office workers	Intervention (n=50): physical training program combined with orientation on posture by means of online videos Control (n=50): orientation per e-mail	9 months	Low back pain	Low back pain episodes; functional disability by means of the Roland-Morris Disability Questionnaire	The scores on the Roland-Morris Disability Questionnaire improved for the intervention group (95%CI -8.41--6.31) and became poorer for the control group (95%CI 0.71-2.65)	7/10
Alexandre et al., 200120	56 nursing professionals	Intervention (n=27): strength and flexibility exercising program combined with educational program for posture Control (n=29): lecture on spine anatomy and patient transfer techniques	4 months	Backache	Low back pain was assessed with a pain intensity VAS. Use of medications and frequency of backache were assessed through a questionnaire	Reduced use of medications (p=0.0002), frequency of pain in home activities (p=0.000) and pain intensity (p=0.008) in group intervention	4/10
Pillastrini et al., 200921	71 nursery school teachers	Intervention (n=35): program to reinforce lumbar extension and strengthen the primary stabilizers of the spine + orientation on low back pain Control (n=36): ergonomic brochure	3 weeks	Neck and low back pain	Physical ability was measured by means of the Roland-Morris Disability Questionnaire and the Oswestry Disability Index. Pain intensity was assessed with VAS	Significant improvement of neck pain (p=0.0246), perceived pain on VAS (62.9%) and physical capacity (37.2%) in group intervention	8/10
Horneij et al., 200122	282 nursing aides and assistant nurses	Intervention 1 (n=90): individual physical training program Intervention 2 (n=93): group stress management program Control (n=99): orientation on environment changes and health	18 months	Backache and interference with work	Musculoskeletal disorders were assessed with the Nordic Musculoskeletal Questionnaire	Group intervention 1 reported less interference of spine discomfort (especially on the low back area) with work compared to the control group (p=0.02). Group intervention 2 did not exhibit any difference compared to the control group (p=0.057)	4/10
Anema et al., 200723	196 workers	Intervention 1 (n=96): workplace assessment and changes and case management Intervention 2 (n=100): orientation on usual care	8 weeks	Return to work and functional status	Workplace assessment and length of sick leaves. Functional status was assessed through a questionnaire	Intervention 1 was associated with better return-to-work outcomes and improved functional status compared to intervention 2 (HR=1,7; 95%CI 1.2-2.3; p=0.002).	7/10
Ewert et al., 200924	169 nurses	Intervention 1 (n=86): warming up, strengthening, stretching and aerobic exercises Intervention 2 (n=83): segmental stabilization exercises, psychological and ergonomic orientation	13 weeks	Backache and interference with work	Pain interference and intensity were measured by means of the West Haven-Yale Multidimensional Pain Inventory and Short Form-36	There was not any statistically significant difference between the groups. Both programs had small to moderate effects. For pain interference, the effect size of intervention 1 was 0.58 and 0.47 for intervention 2	6/10
Nassif et al., 201125	75 workers	Intervention (n=37): muscle strength, flexibility and endurance training sessions Control (n=38): no direct intervention	6 months	Low back pain and flexibility	Pain-related parameters were assessed by means of questionnaires and scales. Pain intensity was assessed on VAS. Physical assessment based on tests	Reduction of pain-related parameters (p<0.025) and pain intensity in group intervention compared to the control group (1.8 vs. 0.51) and improved flexibility (p<0.0001)	4/10
Elfering et al., 201326	54 office workers	Intervention (n=27): vibration training Control (n=27): same training starting 4 weeks later	4 weeks	Musculoskeletal pain and body balance	Musculoskeletal pain was assessed with the Nordic Musculoskeletal Questionnaire. Body balance was assessed by means of the clinical test of sensory integration of balance (CTSIB)	Musculoskeletal pain significantly decreased among the participants who reported low back pain (p<0.05). Body balance was significantly increased (p<0.05)	5/10
Jakobsen et al., 201527	200 healthcare workers from 3 hospitals	Intervention (n=111): supervised high-intensity strength training with resistance bands and kettlebells at the workplace Control (n=89): exercise at home during leisure time	10 weeks	Musculoskeletal pain, muscle strength and use of analgesics	Pain was assessed on VAS. Pain areas were defined based on the Nordic Musculoskeletal Questionnaire. Muscle strength testing. Use of analgesics was assessed through a questionnaire	Pain intensity, back muscle strength and use of analgesics improved in group intervention (p<0.05). Difference between groups was -0.7 for pain intensity (95%CI -0.1--0.3), 5.5 for back muscle strength (95%CI 2.0-9.0) and -0.4 days for use of analgesics (85%CI -0.7-0.2)	7/10
Mayer et al., 201528	96 firefighters	Intervention (n=54): supervised exercise targeting the back and core muscles while on duty in addition to usual physical activity Control (n=42): usual physical activity	24 weeks	Low back pain, muscle strength and endurance	Muscle strength and resistance were assessed by means of the Biering-Sorensen and plank tests	Group intervention had 12% greater (p=0.021) back muscle endurance and 21% greater (p=0.0006) core muscle endurance compared to the control group	7/10
Kim et al., 201529	53 workers	Intervention (n=27): core muscle strengthening program (CORE) Control (n=26): hot-packs and transcutaneous electrical nerve stimulation	2 months	Musculoskeletal pain, range of motion and proprioception	Resting and movement-induced pain were assessed on VAS. Pressure pain was assessed with pressure algometer. Active range of pain-free motion was assessed with inclinometer. Proprioception assessment	The intensity of resting (35.6±5.9 mm) and movement-induced (39.4-9.1 mm) pain significantly decreased in group intervention. Significant improvement of the pressure pain threshold (quadratus lumborum: 2.2±0.7 kg/cm2), active range of motion and proprioception (p<0.05)	5/10
Brandt et al., 201530	13 US Airforce helicopter crewmembers	Intervention (n=6): core strengthening exercises Control (n=7): usual exercising regimen	12 weeks	In-flight low back pain and functional disability	Self-reported pain severity and disability were assessed with Numerical Pain Rating Scale - NPRS and the Modified Oswestry Low Back Pain Disability Index (MODI)	The average score on NPRS significantly decreased in group intervention and increased in the control group (-1.8 vs. +0.1 points). The mean score on MODI significantly decreased in group intervention and increased in the control group (-4.8 vs. +1.7 points)	4/10
Macedo, 201131	50 workers	Intervention (n=29): workplace fitness program with emphasis on stretching, relaxation and ludic activities Control (n=21): did not participate in the fitness program	8 months	Musculoskeletal pain	Pain topography was assessed with the Nordic Musculoskeletal Questionnaire. Pain intensity was assessed with VAS	Group intervention exhibited significant low back pain improvement (p=0.001)	5/10