Chart 2.

Characteristics of studies in the category: different types of guidance and instruments to facilitate implementing guidance

Authors (year)	Sample (n)	Study design	Objective	Analytical instrument	Intervention	Outcome
Bazazan et al.16 (2019)	188 male office workers (operatives from a petrochemical control room) allocated to an intervention group (91) or a control group (97)	Randomized controlled clinical trial	To examine the effect of a posture correction-based intervention on musculoskeletal symptoms and fatigue	NMQ: musculoskeletal symptoms; MFI-20: Multidimensional Fatigue Questionnaire; RULA: to assess posture	Use of biofeedback to transmit communication via an audible and vibration alert to help workers to improve their posture when working	The low-cost device proved of considerable benefit for improving posture and reducing musculoskeletal symptoms and fatigue.
Ailneni et al.20 (2019)	19 workers: 10 women and 9 men	Quasi-experimental study	To evaluate the effect of a wearable posture sensor on posture and on physical demands on the head and neck during office work	Anthropometric measurements, reflective markers on several parts of the body, the floor, the chair, the table edge, and the laptop; infrared cameras: movement capture	Participants performed typing tasks with and without the sensor, sitting and standing up and were allowed to adjust their workstations during the experiment using a psychophysical method	The wearable sensor reduced postural stress on the neck. The effect was more significant when using the standing workstation compared to the sitting workstation.
Yoo & Park21 (2013)	12 workers (men)	Quasi-experimental study	To investigate the difference in kinematics of the neck and trunk segments as well as muscular activation between conditions with and without posture related auditory cueing	Surface electromyography: to measure the activity of the erector spine and upper trapezius; ultrasonic three-dimensional movement; CMSMS: to capture kinematic data, record angles of front and trunk during work, in the sagittal plane	A posture related auditory cueing (PAC) program, that played a cue consisting of a beep followed by a spoken postural correction suggestion at 300 second intervals	The auditory cueing program was positive for preventing unhealthy postures in the workplace and was recommended for practical use in the workplace.
Levanon et al.17 (2012)	66 workers (23 men and 43 women) allocated to a group with biofeedback (22) or a group without biofeedback (23) and control group without intervention (21)	Randomized controlled clinical trial	To test the efficacy of a workplace intervention for reducing musculoskeletal complaints among computer workers.	NMQ: to assess pain symptoms; RULA: to assess risk factors of posture and forced effort of arms, trunk, and legs; DCSQ: for psychosocial assessment of psychological demands, attitudes, and support in the workplace; SEMG: to report muscle activity	Three intervention programs: ergonomic intervention, including biofeedback and surface electromyography, intervention without biofeedback, and a control group	The interventions were effective for reducing workers’ musculoskeletal complaints and pain. The intervention with biofeedback had no unique contribution in comparison to other groups.

CMSMS = ultrasonic movement analysis system; DCSQ = Swedish Demand Control and Support Questionnaire; SEMG = surface electromyography; MFI-20 = Multidimensional Fatigue Inventory; NMQ = Nordic Musculoskeletal Questionnaire; RULA = Rapid Upper Limb Assessment.