NCT07561112

Brief Summary

This study investigates the long-term effects of implementing a passive back-support exoskeleton during manual order-picking work in a real-world warehouse environment. Work-related musculoskeletal disorders, particularly low back pain, are common among logistics workers due to frequent lifting, repetitive movements, and awkward postures. Although laboratory studies suggest that occupational exoskeletons can reduce biomechanical load, evidence from long-term, real-world workplace implementations remains limited. The RELAX project is an 18-month controlled in-field intervention study conducted in two departments of a Danish warehouse. Approximately 90 full-time warehouse workers will participate. Workers in the intervention department will use a passive back-support exoskeleton during manual order-picking tasks, while workers in the control department will continue their work as usual. The primary outcomes include sickness absence, employee turnover, perceived work intensity, and musculoskeletal discomfort. Secondary outcomes include productivity, user acceptance of the exoskeleton, and cost-effectiveness of the intervention. Outcomes will be assessed through company records, repeated questionnaires, and focus-group interviews over the 18-month period. By combining longitudinal quantitative outcomes with qualitative process evaluation, the study aims to determine whether long-term use of a passive back-support exoskeleton can improve worker well-being and reduce work-related musculoskeletal burden without negatively affecting productivity. The results may inform workplace policies and future implementation of occupational exoskeletons in physically demanding industries.

Trial Health

63
Monitor

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
90

participants targeted

Target at P50-P75 for not_applicable

Timeline
40mo left

Started Aug 2026

Longer than P75 for not_applicable

Geographic Reach
1 country

1 active site

Status
not yet recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

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Study Timeline

Key milestones and dates

First Submitted

Initial submission to the registry

April 20, 2026

Completed
11 days until next milestone

First Posted

Study publicly available on registry

May 1, 2026

Completed
3 months until next milestone

Study Start

First participant enrolled

August 1, 2026

Expected
6 months until next milestone

Primary Completion

Last participant's last visit for primary outcome

January 31, 2027

2.8 years until next milestone

Study Completion

Last participant's last visit for all outcomes

October 31, 2029

Last Updated

May 1, 2026

Status Verified

April 1, 2026

Enrollment Period

6 months

First QC Date

April 20, 2026

Last Update Submit

April 24, 2026

Conditions

Work-Related Musculoskeletal Disorders

Keywords

Occupational ExoskeletonsMusculoskeletal DisordersManual Materials HandlingErgonomicsAssistive TechnologyWarehouse

Outcome Measures

Primary Outcomes (2)

  • 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. Adapted from Kim et al., 2019.

    Reported at baseline, Month 3, Month 6, Month 9, Month 12, Month 15, and Month 18.

  • 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.

    Reported at baseline, Month 3, Month 6, Month 9, Month 12, Month 15, and Month 18.

Secondary Outcomes (3)

  • Sickness Absence

    Reported at baseline, Month 3, Month 6, Month 9, Month 12, Month 15, and Month 18.

  • Employee Turnover

    Time-to-event. Reported as the timepoint (in months) from baseline, when the resignation occurs.

  • Productivity

    Weekly during the 18-month intervention (Baseline to month 18).

Other Outcomes (3)

  • Exoskeleton evaluation / User acceptance

    Reported at baseline, Month 3, Month 6, Month 9, Month 12, Month 15, and Month 18.

  • Process evaluation

    Reported at baseline, Month 3, Month 6, Month 9, Month 12, Month 15, and Month 18.

  • Exoskeleton use

    Weekly during the 18-month intervention (Baseline to month 18).

Study Arms (2)

Exoskeleton group

EXPERIMENTAL

Group receiving intervention

Device: Use of an occupational passive back-exoskeleton

Control Group

NO INTERVENTION

Group receiving no intervention

Interventions

Use of an occupational passive back-exoskeletonDEVICE

Use of the IX Back AIR (SuitX by Ottobock) for 18 months during daily order picking tasks

Exoskeleton group

Eligibility Criteria

Age18 Years - 65 Years
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64), Older Adult (65+)

You may qualify if:

  • age 18-65 years at enrolment
  • full-time employment in the current work department
  • no major pain or injuries affecting daily work tasks

You may not qualify if:

  • anthropometric characteristics preventing adequate fit of the exoskeleton
  • part-time employment
  • pregnancy or anticipated prolonged absence from work during the study period (standard vacation not included)
  • If a participating worker from either the intervention or control group transfers to another department within the company during the intervention period for reasons unrelated to the intervention, the participant will be excluded from the study. Such cases will be classified as dropouts and the corresponding data will be reported as lost to follow-up.

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Aalborg University

Aalborg, 9000, Denmark

Location

Related Publications (16)

  • 1) J De Kok. Work-related musculoskeletal disorders: prevalence, costs and demographics in the EU European Risk Observatory Report. European Agency for Safety and Health at Work (2019) EU OSHA.

    BACKGROUND

  • 2) S Skals, R Bláfoss, MS Andersen, M De Zee, LL Andersen. Manual material handling in the supermarket sector. Part 1: Joint angles and muscle activity of trapezius descendens and erector spinae longissimus, Applied Ergonomics. 92 (2020) 103340.

    BACKGROUND

  • 3) JN Katz. Lumbar disc disorders and low-back pain: socioeconomic factors and consequences, JBJS. 88 (2006) 21-24.

    BACKGROUND

  • 4) MS. Popova, SP Nikolova, & SI Filkova. Demographic and Occupational Determinants of Work-Related Musculoskeletal Disorders: A Cross-Sectional Study. Journal of Functional Morphology and Kinesiology (2025) 10(2), 137.

    BACKGROUND

  • 5) D Hoy, C Bain, G Williams, L March, P Brooks, F Blyth, ... & R Buchbinder. A systematic review of the global prevalence of low back pain. Arthritis & rheumatism (2012) 64(6), 2028-2037.

    BACKGROUND

  • 6) S Toxiri, MB Näf, M Lazzaroni, J Fernández, M Sposito, T Poliero, et al. Back-Support Exoskeletons for Occupational Use: An Overview of Technological Advances and Trends, IISE Transactions on Occupational Ergonomics and Human Factors. 7 (2019) 237.

    BACKGROUND

  • 7) H Kazerooni, W Tung, M Pillai. Evaluation of Trunk-Supporting Exoskeleton, Proceedings of the Human Factors and Ergonomics Society Annual Meeting. 63 (2019) 1080.

    BACKGROUND

  • 8) S Crea, P Beckerle, M De Looze, K De Pauw, L Grazi, T Kermavnar, et al., Occupational exoskeletons: A roadmap toward large-scale adoption. Methodology and challenges of bringing exoskeletons to workplaces, Wearable Technology 2 (2021) e11.

    BACKGROUND

  • 9) J Howard, VV Murashov, BD Lowe, M Lu. Industrial exoskeletons: Need for intervention effectiveness research, American Journal Industrial Medicine 63 (2020) 201-208.

    BACKGROUND

  • 10) SE Kranenborg, C Greve, MF Reneman, CC Roossien. Side-effects and adverse events of a shoulder- and back-support exoskeleton in workers: A systematic review, Applied Ergonomics 111 (2023) 104042.

    BACKGROUND

  • 11) J Theurel, K Desbrosses. Occupational exoskeletons: overview of their benefits and limitations in preventing work-related musculoskeletal disorders. IISE Transactions on Occupational Ergonomics and Human Factors. 7 (2019) 264-280.

    BACKGROUND

  • 12) MA Nussbaum, BD Lowe, M De Looze, C Harris-Adamson, M Smets. An Introduction to the Special Issue on Occupational Exoskeletons, IISE Transactions on Occupational Ergonomics and Human Factors. 7 (2020) 153.

    BACKGROUND

  • 13) M Bär, B Steinhilber, MA Rieger, T Luger. The influence of using exoskeletons during occupational tasks on acute physical stress and strain compared to no exoskeleton - A systematic review and meta-analysis, Applied Ergonomics. 94 (2021) 103385.

    BACKGROUND

  • 14) S Madinei, S Kim, JH Park, D Srinivasan & MA Nussbaum. A novel approach to quantify the assistive torque profiles generated by passive back-support exoskeletons (2022) Journal of Biomechanics, 145, 111363.

    BACKGROUND

  • 15) S Kim, MA Nussbaum, M Smets, S Ranganathan. Effects of an arm-support exoskeleton on perceived work intensity and musculoskeletal discomfort: An 18-month field study in automotive assembly, American Journal Industrial Medicine 64 (2021) 905-914.

    BACKGROUND

  • 16) A. Hedge, S. Morimoto, S., & Mccrobie, D. (1999). Effects of keyboard tray geometry on upper body posture and comfort. Ergonomics, 42(10), 1333-1349.

    BACKGROUND

MeSH Terms

Conditions

Musculoskeletal Diseases

Study Officials

  • Pascal Madeleine, Professor

    Aalborg University

    STUDY DIRECTOR

Central Study Contacts

Lasse S. Jakobsen, PhD

CONTACT

0045 72332998lsja@hst.aau.dk

Pascal Madeleine, Professor

CONTACT

0045 99408833pm@hst.aau.dk

Study Design

Study Type
interventional
Phase
not applicable
Allocation
NON RANDOMIZED
Masking
NONE
Purpose
PREVENTION
Intervention Model
PARALLEL
Model Details: This is a controlled parallel-group workplace intervention study conducted over 18 months. Two comparable warehouse departments will be followed simultaneously: one department will implement a passive back-support exoskeleton during regular work tasks, while the other will continue usual practice without exoskeleton use. Allocation occurs at department level and is not randomized. All eligible full-time employees in both departments will be invited to participate and will be observed throughout the study period. Outcomes will be assessed repeatedly during follow-up using questionnaires and company records, allowing comparison of changes over time between the intervention and control groups under real-world working conditions.
Sponsor Type
OTHER
Responsible Party
PRINCIPAL INVESTIGATOR
PI Title
PostDoc researcher

Study Record Dates

First Submitted

April 20, 2026

First Posted

May 1, 2026

Study Start (Estimated)

August 1, 2026

Primary Completion (Estimated)

January 31, 2027

Study Completion (Estimated)

October 31, 2029

Last Updated

May 1, 2026

Record last verified: 2026-04

Data Sharing

IPD Sharing
Will share
Shared Documents
STUDY PROTOCOL, SAP, ICF
Time Frame
The Study Protocol and Informed Consent Form (ICF) will be made publicly available prior to initiation of the intervention. The Statistical Analysis Plan (SAP) will be made available prior to conducting the statistical analyses and before completion of the intervention. All data will be made publicly available through scientific publications or supplementary materials upon completion of the study.
Access Criteria
All supporting materials and scientific publications will be published open access.

Locations

DK(1)