The Impact of Back-supporting Exoskeletons for Manual Order Picking in Danish Warehouses - The RELAX Project

Perceived Work Intensity

Assessed using two 10-point Likert-scale questions on 1) how much they exert themselves during a shift and 2) how exhausted they feel at the end of a shift.

Musculoskeletal Discomfort

Assessed using the Cornell Musculoskeletal Discomfort Questionnaire (CMDQ), completed monthly by workers as part of the questionnaire battery. The questionnaire includes three questions on 1) how often they experienced discomfort during the last workweek (1-5, 5 being worst), 2) how uncomfortable it was (1-3, 3 being worst), and 3) if the discomfort interfered with their ability to work (1-3, 3 being worst). All questions will be answered for separate body regions. Analyses will primarily focus on reports of back discomfort.

Sickness Absence

Measured as the number of days of sick leave per month as reported by the company. To assess whether sick leave was related to musculoskeletal issues, the questionnaire will include the question: "Have you had any sick leave related to musculoskeletal discomfort within the last month?"

Employee Turnover

Measured as the number of monthly resignations in the respective department as reported by the company.

Productivity

Productivity is a key performance indicator monitored by the company reported in packages per hour for each individual worker. In this study productivity will be reported as a weekly average.

Exoskeleton evaluation / User acceptance

Evaluations of the exoskeleton will be conducted using a 6-item 10-point Liker-Scale questionnaire: Q1: What is your perception of the overall fit and comfort of the exoskeleton when performing your job? Q2: What is your perception of the thermal comfort typically (and/or feelings of sweatiness) when using the exoskeleton? Q3: What is your perception of balance (or any sense of imbalance) while using the exoskeleton? Q4: Do you feel that your range of motion was at all limited while using the exoskeleton? Q5: When using the exoskeleton to perform your job, how do you think this affected your overall safety? Q6: Overall, does using the exoskeleton positively or negatively affect your performance? Additionally, the questionnaire will include the open-ended questions: Q7: What do you most like about the exoskeleton? Q8: What do you least like about the exoskeleton? Q9: If you could change anything about the exoskeleton, what would you change?

Process evaluation

A process evaluation will be conducted to support interpretation of the intervention outcomes and to document implementation fidelity, user acceptance, and contextual factors influencing exoskeleton use. Process evaluation data will be collected every 6th month throughout the 18-month intervention period. Qualitative process data will be collected through repeated focus-group interviews with workers from the intervention group and with relevant stakeholders. The interviews will explore experiences with BSE use, integration into daily work routines, perceived benefits and drawbacks, and organizational factors affecting implementation.

Exoskeleton use

During the intervention period, workers will report daily exoskeleton use using operational logs. Specifically, usage will be recorded through a stamp system each time the exoskeleton is used. In this study exoskeleton use will be reported as a weekly average.